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35812
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i

NASA/TP—2009–215796

North Atlantic Basin Tropical Cyclone Activity 

in Relation to Temperature and DecadalLength Oscillation Patterns

Robert M. Wilson

Marshall Space Flight Center, Marshall Space Flight Center, Alabama

June 2009

National Aeronautics and

Space Administration

Marshall Space Flight Center • MSFC, Alabama 35812
ii

Available from:

NASA Center for AeroSpace Information

7115 Standard Drive

Hanover, MD 21076 –1320

443–757–5802

This report is also available in electronic form at

<https://www2.sti.nasa.gov>
iii

TABLE OF CONTENTS

1. INTRODUCTION ............................................................................................................. 1

2. RESULTS AND DISCUSSION ......................................................................................... 3

2.1 Tropical Cyclone Frequencies (1950–2008) .................................................................. 3

2.2 Latitudinal and Longitudinal Variation of Tropical Cyclones ..................................... 6

2.3 Peak Wind Speed and Lowest Pressure Variation ........................................................ 22

2.4 Effects of El Niño and La Niña ................................................................................... 26

2.5 First Differences in 10-yma Values of Tropical Cyclone Frequencies ........................... 28

2.6 First Differences in 10-yma Values of Latitudinal and Longitudinal

Genesis Locations ........................................................................................................ 31

2.7 First Differences in 10-yma Values of Peak Wind Speeds and Pressures ...................... 32

2.8 Temperature and Decadal-Length Oscillations ............................................................ 34

2.9 First Differences in 10-yma Values of <AT>, <ONI>, <SOI>, <NAO>, 

and <EA> ................................................................................................................... 38

2.10 Single- and Bi-Variate Fits ........................................................................................... 38

3. SUMMARY ........................................................................................................................ 46

APPENDIX ............................................................................................................................. 50

REFERENCES ....................................................................................................................... 73
iv

LIST OF FIGURES

 1. Yearly variation of (a) NTC, (b) NH, (c) NMH, (d) NUSLFH, and (e) NENM 

and NLNM for the interval 1950–2008. Also given is the frequency distribution 

for (a)–(d) .................................................................................................................... 4

 2. Yearly variation of (a) <LAT> and (b) <LONG> for the interval 1950–2008 ............. 16

 3. Yearly variation of the centroid location of North Atlantic basin tropical 

cyclones ....................................................................................................................... 18

 4. Map of the North Atlantic basin hurricane tracking chart, National 

Hurricane Center, Miami, FL ...................................................................................... 21

 5. Yearly variation of the number of tropical cyclones in selected geographical 

areas: (a) Group 1 (Gulf of Mexico), (b) group 2 (Caribbean Sea), (c) group 3 

(east coast), (d) group 4 (lower North Atlantic-Cape Verdi), and (e) group 5 

(open North Atlantic) .................................................................................................. 23

 6. Yearly variation of (a) PWS and (b) <PWS> for the interval 1950–2008 ..................... 24

 7. Yearly variation of (a) LP and (b) <LP> for the interval 1950–2008. Also given 

are the names of the most powerful tropical cyclones (LP≤ 925 mb) ............................ 25

 8. Yearly variation of the (a) low-latitude formation groups (2+4), (b) high-latitude 

formation groups (1+3+5), and (c) NENM for the interval 1950–2008 ...................... 29

 9. Yearly variation of the first differences of the 10-yma values of (a) NTC, 

(b) NH, (c) NMH, and (d) NUSLFH for the interval 1950–2002. Also given 

is the frequency distribution for (a)–(d) ....................................................................... 30

10. Yearly variation of the first differences of the 10-yma values of (a) <LAT> 

and (b) <LONG> for the interval 1950–2002 .............................................................. 32

11. Yearly variation of the first differences of the 10-yma values of (a) PWS, 

(b) <PWS>, (c) LP, and (d) <LP> for the interval 1950–2002 ...................................... 33

12. Yearly variation of the (a) <AT> and (b) <ONI> for the interval 1950–2008 .............. 35

13. Yearly variation of the (a) <SOI>, (b) <NAO>, and (c) <EA> for the interval 

1950–2008 .................................................................................................................... 37

14. Yearly variation of the first differences of the 10-yma values of (a) <AT>, 

(b) <ONI>, (c) <SOI>, (d) <NAO>, and (e) <EA> for the interval 1950–2002 .......... 39
v

LIST OF TABLES

 1. Summary of yearly values for North Atlantic basin tropical cyclones ......................... 7

 2. Summary of 10-yma values for North Atlantic basin tropical cyclones ....................... 9

 3. Poisson distributions for NTC, NH, NMH, and NUSLFH based 

on 1950–2008 statistics ................................................................................................. 11

 4. Frequency of U.S. land strikes by state ........................................................................ 12

 5. Listing of U.S. land-falling hurricanes ......................................................................... 12

 6. Proportion: NUSLFH/NH for 1950–2008 (based on GL) ........................................... 19

 7. Listing of EN and LN events based on ONI (ERSST.v3b) .......................................... 27

 8. Statistical aspects of EN and LN events based on ONI (ERSST.v3b) ......................... 27

 9. Inferred statistically important linear regressions (cl>95%) ........................................ 40

10. Inferred statistically important linear regressions (cl>95%), grouped by tropical 

cyclone parameter in descending order of r ................................................................. 41

11. Statistically important bi-variate correlations, grouped by tropical cyclone 

parameter in descending order of R ............................................................................. 42

12. Results of single-variate linear correlation analysis using the limited time 

interval 1990–2003 (n=14), grouped by tropical cyclone parameter 

in descending order of r ............................................................................................... 44

13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 ............... 50
vi

LIST OF ABBREVIATIONS AND ACRONYMS

2-mma 2-mo moving average

10-yma 10-yr moving average

<AT> average Armagh Observatory temperature

B before

cl confidence level

Class. classification

CSU Colorado State University

Dur duration

EA East Atlantic

<EA> average East Atlantic

EN El Niño

ENSO El Niño-Southern Oscillation

ERSST.v3b extended reconstructed sea surface temperature, version 3b

fd first difference

FSD first storm day

GL genesis location

H hurricane

LAT latitude

<LAT> average latitude

LN La Niña

LONG longitude

<LONG> average longitude

LP lowest pressure

<LP> average lowest pressure

M moderate

max maximum

MH major hurricane

MSFC Marshall Space Flight Center

NAO North Atlantic Oscillation
vii

LIST OF ABBREVIATIONS AND ACRONYMS (Continued)

<NAO> average North Atlantic Oscillation

NASA National Aeronautics and Space Administration

NENM number of El Niño months

NH number of hurricanes 

NLNM number of La Niña months

NMH number of major hurricanes

NNM number of neutral months

NOAA National Oceanic and Atmospheric Administration

NTC number of tropical cyclones

NUSLFH number of U.S. land-falling hurricanes 

ONI Oceanic Niño Index

<ONI> average Oceanic Niño Index

P proportion

PWS peak wind speed

<PWS> average peak wind speed

S strong

SNBR storm number (from best track data)

SOI Southern Oscillation Index

<SOI> average Southern Oscillation Index

SS subtropical storm

TS tropical storm

TSR tropical storm risk

U.S. United States

USLFH U.S. land-falling hurricane

W weak
viii

NOMENCLATURE

d first-difference deviation

f frequency

m mean

N number

P(r) probability of r events occurring using Poisson distribution

R coefficient of correlation for bi-variate fit

R×R coefficient of determination for bi-variate fit

r coefficient of linear correlation or number of events in Poisson distribution

r×r coefficient of determination

sd standard deviation

SE standard error of estimate for bi-variate fit

se standard error of estimate
1

TECHNICAL PUBLICATION

NORTH ATLANTIC BASIN TROPICAL CYCLONE ACTIVITY IN RELATION 

TO TEMPERATURE AND DECADAL-LENGTH OSCILLATION PATTERNS

1. INTRODUCTION

Previously, an extended forecast of the frequencies of tropical cyclone activity for the 2009 

North Atlantic basin hurricane season was given.1 Three conclusions resulting from that study were 

(1) continued increased activity exceeding long-term averages should be expected during the 2009 

hurricane season, (2) temperature now appears to be the principal driver of the increased activity and storm strength, especially during the current interval of high activity (1995–2008), and 

(3) near-record values are possible during the 2009 hurricane season, especially if warming continues 

unabated and El Niño (EN) does not recur. Based on the current high-activity interval, the central 

50% frequencies for numbers of tropical cyclones, hurricanes, and major (or intense) hurricanes were 

found to be, respectively, about 12–18, 6–10, and 3–5, with only a 5% chance of exceeding 23, 13, or 

7, respectively, during the 2009 hurricane season.

In the previous study, the role of decadal-length oscillation was examined using the Oceanic 

Niño Index (ONI), which is derived from the Extended Reconstructed Sea Surface Temperature, 

version 3 (ERSST.v3). The ONI is a 3-mo running mean of the sea-surface temperature anomalies 

of the Niño 3.4 region, located between 5° N. and 5° S. latitude and 120° W. and 170° W. longitude, 

and based on the 1971–2000 base period.2 It is updated monthly and has become the de facto means 

for defining the occurrences of warm EN and cold La Niña (LN) events. Because the ERSST.v3 data 

set has recently (in December 2008) been superseded by ERSST.v3b and will no longer be updated, 

it seems prudent to repeat the analyses using the newer ONI values. Also, it seems prudent to examine other indices, like the Southern Oscillation Index (SOI), the North Atlantic Oscillation (NAO) 

index, and the East Atlantic (EA) index, as well, for determining possible effects of decadal-length 

oscillation on the expected frequencies of North Atlantic basin tropical cyclones, especially for the 

upcoming 2009 hurricane season.

Additionally, in the previous study, the 2008 frequencies of North Atlantic basin tropical 

cyclone activity were taken directly from the yearend National Hurricane Center’s Tropical Cyclone 

Reports,3 which are found to differ slightly from the recently published Atlantic tracks file 1851–

2008.4 For example, whereas tropical cyclone Laura was described as a tropical storm having peak 

wind speed (PWS) equal to 50 kt in the yearend report, according to the best track file, it now is 

classified as a hurricane having PWS=70 kt. Other slight differences are also found for several of 

the other tropical cyclones as well. Because the best tracks data file was employed for the interval 

of 1950–2007, to be consistent, the analyses of the former study will be repeated here using the best 

tracks data including the year 2008.
2

In this NASA Technical Publication, the frequencies of North Atlantic basin tropical cyclones, 

hurricanes, major hurricanes, and U.S. land-falling hurricanes for the interval 1950–2008 are examined, hopefully, leading to a more refined prediction for the 2009 hurricane season. Also examined 

are PWS, average PWS (<PWS>), lowest pressure (LP), average LP (<LP>), and the genesis location (average latitude <LAT> and longitude <LONG>; i.e., the average latitudinal and longitudinal 

position of the yearly tropical cyclones when first attaining sustained winds of 34 kt or greater) of 

the tropical cyclones, as well as the first differences of their 10-year moving average (10-yma) values. 

Linear regression analyses between the 10-yma values of the aforementioned parameters against 

10-yma values of surface-air temperature as measured at the Armagh Observatory in Northern Ireland (<AT>) and against 10-yma values of ONI, SOI, NAO, and EA are also investigated, as well as 

bi-variate regression analyses using combinations of temperature and pressure indices. This study is 

a continuation of climate-related investigations that have been performed at Marshall Space Flight 

Center (MSFC) over the past decade concerning North Atlantic basin tropical cyclones, El NiñoSouthern Oscillation (ENSO), and other climate-related topics.1,5–18
3

2. RESULTS AND DISCUSSION

2.1 Tropical Cyclone Frequencies (1950–2008)

Figure 1 displays the yearly frequencies of North Atlantic basin tropical cyclones for the 

interval 1950–2008: (a) The number of tropical cyclones (NTC), (b) the number of hurricanes (NH), 

(c) the number of major hurricanes (NMH), (d) the number of U.S. land-falling hurricanes 

(NUSLFH), and (e) the number of El Niño and La Niña months (NENM and NLNM, respectively) based on the ONI values using ERSST.v3b. In figure 1(a)–(d), the thin, jagged line represents 

the actual yearly counts and the thick, smoothed line represents the 10-yma (or trend line). The 

total number of events is displayed for each grouping in the left portion of each subpanel. It should 

be noted that NH now numbers 371, as compared to 369 in the previous publication.1 The higher 

number reflects the change in status for Laura in 2008 (from tropical storm to hurricane) and for 

Keith in 1988 listed in the best tracks file as a tropical storm, yet having PWS=65 kt, thus making it 

a hurricane by the standard used in this study. (Namely, if the PWS during the best tracks window 

of observations meets or exceeds 64 kt, it will be counted as a hurricane, and if the PWS meets or 

exceeds 96 kt, it will be counted as a major hurricane.) Also displayed is a thin, horizontal line that 

represents the mean for the entire interval, and the standard deviation (sd), whose values appear to 

the right in each subpanel (a)–(d). Thus, for the interval 1950–2008, on average, there have been 10.8 

tropical cyclones, 6.3 hurricanes, 2.7 major hurricanes, and 1.6 U.S. land-falling hurricanes occurring 

in any given year (season).

To the extreme right of subpanels (a)–(d) are the frequency distributions. Hence, the primary 

modes are 8 and 11 for NTC, 4 for NH, 2 for NMH, and 1 for NUSLFH. Noticeable in each subpanel is that the parametric trend line (i.e., the 10-yma values) is now above the long-term average, 

beginning in the 1990s. The highest NTC (28) occurred in 2005, while the lowest (4) occurred in 1983. 

Similarly, the highest NH (15) occurred in 2005, while the lowest (2) occurred in 1983. The highest NMH (8) occurred in 1950, while no major hurricanes occurred in 1968, 1972, 1986, and 1994. 

The highest NUSLFH (6) occurred in 1985, 2004, and 2005, while no U.S. land-falling hurricanes 

occurred in 1951, 1962, 1973, 1978, 1981, 1982, 1990, 1994, 2000, 2001, and 2006. All distributions 

are rightward (or positively) skewed.

On the basis of the behavior of NMH, it can be argued that the overall interval of 1950–2008 

can be subdivided into two high-activity intervals (1950–1965 and 1995–2008) separated by one lowactivity interval (1966–1994). During the current high-activity interval, 12 of 14 years have had NTC 

above its long-term mean (10.8), averaging instead ≈14.9 per year (sd=4.7; range 8 to 28). Similarly, 

11 of 14 years have had NH above its long-term mean (6.3), averaging ≈8.1 per year (sd=3; range 3 

to 15), and 10 of 14 years have had NMH above its long-term mean (2.7), averaging ≈3.9 per year 

(sd=1.8; range 1 to 7). Eight of 14 years have had NUSLFH above its long-term mean (1.6), averaging 2.1 per year (sd=2; range zero to 6). Thus, the current high-activity interval has averaged ≈5.3 

additional tropical cyclones, ≈2.7 additional hurricanes, ≈2.3 additional major hurricanes, and ≈0.8 

additional U.S. land-falling hurricanes, as compared to the preceding low-activity interval.
4

1950 1960 1970 1980 1990 2000

30 20 10

0

5

10

12

6

0

6

12

(e)

(d)

(c)

Year

Frequency

NENM NLNM

 m = 2.7

sd = 2.0

 m = 1.6

sd = 1.5

10

10

5

5

NUSLFH

NUSLFH

16 14 12 10 8 6 4 2

0

5

10

Frequency

NMH

10 8 6 4 2

0

5

15

10

20

Frequency

NH

NMH

(b)

 m = 6.3

sd = 2.6

10

15

20

5

∑NH = 371

(a) 8 6 4 2

0

5

15

10

20

25

30

Frequency

NTC

NH NTC

 m = 10.8

sd = 4.0 10

15

20

25

30

5

∑NTC = 639

1950 – 2008

∑NMH = 159

∑NUSLFH = 95

∑NENM = 171

∑NLNM = 195

Figure 1. Yearly variation of (a) NTC, (b) NH, (c) NMH, (d) NUSLFH, and (e) NENM 

and NLNM for the interval 1950–2008. Also given is the frequency distribution 

for (a)–(d).
5

Concerning the occurrences of EN and LN (fig. 1(e)), overall, there have been 171 NENM 

and 195 NLNM, implying 342 ENSO-neutral months. Thus, about half the time, ENSO-neutral conditions have prevailed, while about one-quarter of the time each, an extreme in the ENSO cycle has 

occurred. During the current high-activity interval (1995–2008), there have been 81 ENSO-neutral 

months, 45 NLNM, and 42 NENM. During the first high-activity interval (1950–1965; actually the 

beginning of this supposed high-activity interval occurs before 1950), there were 94 ENSO-neutral 

months, 64 NLNM, and 34 NENM, while during the low-activity interval (1966–1994), there were 

167 ENSO-neutral months, 86 NLNM, and 95 NENM. Thus, during the combined high-activity 

intervals (of about the same length as the low-activity interval), there have been 175 ENSO-neutral 

months, 109 NLNM, and 76 NENM. It appears then that during high-activity intervals, there seems 

to be somewhat greater likelihood of having more LN months and fewer EN months, while during low-activity intervals, the reverse seems true. More will be said of EN and LN events in a later 

section.

Table 13 provides the basic information utilized in this study, spanning the interval 1945–

2008, so that 10-yma values can be constructed for interpretation (1950–2003). Because of its length, 

it is placed in the appendix to avoid interruption of the flow in the presentation of the results of 

this study. The table is arranged by year and storm number (SNBR) adapted from the aforementioned best tracks data.4 Given is the name of the tropical cyclone (otherwise, coded “unnamed”); 

its classification, where TS means tropical storm (i.e., 34 kt ≤ PWS < 64 kt), H means hurricane (i.e. 

64 kt ≤ PWS < 96 kt), and MH means major hurricane (i.e., PWS ≥96 kt); the first storm day (FSD, 

meaning the first calendar month/day in the best tracks data when the sustained wind speed equaled 

or exceeded 34 kt); the genesis location (GL) in terms of N. latitude and W. longitude (meaning the 

latitude and longitude of the tropical cyclone on FSD, expressed in degrees north and west, respectively); the group location (meaning the general area of the North Atlantic basin where the GL is 

located, where 1 refers to the Gulf of Mexico area, 2 refers to the Caribbean Sea area, 3 refers loosely 

to the east coastal area—north of Hispaniola and westward from just east of Bermuda, 4 refers to 

the lower North Atlantic basin-Cape Verdi area, and 5 is the open North Atlantic basin area); the 

PWS (meaning the peak wind speed in knots during the window of observations contained in the 

best tracks data); the LP (meaning the lowest pressure in millibars during the window of observations contained in the best track data); and the USLFH (meaning the state or states where the U.S. 

land-falling hurricane struck and the strength of the U.S. land-falling hurricane based on the SaffirSimpson hurricane scale.19 Occasionally, the term SS (for subtropical storm) is used in the classification column. However, based upon the reported PWS during the window of observations in the best 

track file, the term TS or H appears beside SS to show how the tropical cyclone was counted in this 

study. Concerning the USLFH column, it is important to remember that tropical cyclones classified 

as category 3 or higher strike the U.S. coast as major hurricanes (peak sustained winds in excess of 

95 kt). Only Camille in 1969 and Andrew in 1992 struck the U.S. coastline as category 5 tropical 

cyclones. The devastation of Katrina in 2005 (a category 3 storm at landfall) took the lives of about 

1,500 people and is the costliest hurricane to date, costing more than $84 billion in 2006 dollars; see 

http://www.nhc.noaa.gov/Deadliest_Costliest.shtml.20 The second costliest hurricane is Andrew in 

1992, costing more than $48 billion in 2006 dollars. For each year, a summary is provided, giving 

NTC, NH, NMH, NUSLFH, PWS, <PWS>, LP, <LP>, and the average GL of all tropical cyclones 

in the year, in terms of N. latitude and W. longitude.
6

Table 1 provides the record of yearly counts of NTC, NH, NMH, and NUSLFH that are 

plotted as the thin, jagged line in figure 1, and NLNM, NNM (i.e., the number of ENSO-neutral 

months), and NENM. It also provides yearly values of PWS and LP and yearly averages of <LAT>, 

<LONG>, <PWS>, <LP>, <ONI>, <AT>, <SOI>, <NAO>, and <EA> that will be plotted in 

later figures, and it provides the names of those tropical cyclones having PWS ≥140 kt during the 

interval of 1945–2008. Similarly, table 2 provides the record of yearly 10-yma values for each of the 

parameters that are plotted as the thick, smoothed lines in the appropriate figures (1950–2003).

Table 2 and figure 1 clearly show that the trend lines for NTC, NH, NMH, and NUSLFH 

are now above their long-term averages. In fact, for NTC, the value for 2003 (15.3) is more than 40% 

higher than the largest value seen in the 1950s (10.6 in 1952 and 1953) and ≈70% higher than the lowest value seen in the low-activity interval. For NH, its 2003 value (8.2) is ≈17% higher than its peak 

value in the 1950s (7 in 1951) and more than 60% higher than the lowest value seen in the low-activity 

interval. For NMH, its 2003 value (3.8) is comparable to the highest value seen in the 1950s (4 in 1953 

and 1954), which is also true for NUSLFH (2003, having a value of 2.2, and 1950 and 1951, having 

a value of 2.3), both being more than 140% higher than the lowest values seen in the low-activity 

interval. Comparisons for the other parameters will be discussed in later sections.

Table 3 shows the Poisson distributions1,21 for NTC, NH, NMH, and NUSLFH. The central 50% intervals are about 8–12 for NTC (actually 55.4%), 4–7 for NH (actually 57.5%), 1–3 for 

NMH (actually 64.7%), and 1–2 for NUSLFH (actually 58.1%). Concerning NUSLFH, while there 

is about a 20.2% probability of having no U.S. land-falling hurricanes during any given season, there 

is about a 21.5% probability of having 3 or more U.S. land-falling hurricanes.

Table 4 gives the frequency of U.S. land strikes by state for the three time intervals, 1950–

1965, 1966–1994, and 1995–2008, and for the entire interval 1950–2008. Clearly, the state of Florida 

has the highest number of land strikes, accounting for more than 28% of all land strikes. This is not 

unexpected owing to Florida’s long coastline and being a peninsula between the Gulf of Mexico and 

the North Atlantic Ocean. The number of strikes on Florida has actually increased with the passage 

of time, from 11 in the first interval to 21, so far, in the current interval. North Carolina, Louisiana, 

and Texas round out the top double-digit, land-struck states that together with Florida, account for 

two-thirds of all land strikes by hurricanes in the United States during the interval 1950–2008.

Although there were 95 U.S. land-falling hurricanes during 1950–2008, they accounted for 

159 separate land strikes. Many of the U.S. land-falling hurricanes obviously had multiple land 

strikes. For example, Donna in 1960 had eight land strikes as it went up the eastern seaboard. Table 5 

provides a convenient listing of U.S. land-falling hurricanes for 1945–2008. In 2008, there were three 

U.S. land-falling hurricanes, including Dolly, Gustav, and Ike.

2.2 Latitudinal and Longitudinal Variation of Tropical Cyclones

Figure 2 displays the yearly average latitudinal (fig. 2(a)) and longitudinal (fig. 2(b)) position of the combined tropical cyclones as determined from their GL values. Essentially, it maps 

the yearly variation of their centroid positions. The construction of the plots follows that of figure 1, with the thin, jagged lines representing the yearly averages and the thick, smoothed lines 
7

Table 1. Summary of yearly values for North Atlantic basin tropical cyclones.

Year NTC NH NMH NUSLFH

GL

PWS <PWS> LP <LP> <ONI> NLNM NNM NENM <AT> <SOI> <NAO> <EA> Comment <Lat> <Long>

1945 11 5 3 3 17.5 75.2 120 72.7 951 974.8 – – – – 10.29 4.59 – –

1946 6 3 1 1 23.1 82.6 115 63.3 975 977.0 – – – – 9.23 –6.71 – –

1947 9 5 2 3 19.2 72.4 140 73.3 947 969.7 – – – – 9.15 2.31 – – Unnamed

1948 9 6 4 3 19.1 68.4 115 78.9 963 983.5 – – – – 9.71 –1.17 – –

1949 13 7 3 3 19.2 66.2 130 74.6 954 979.7 – – – – 10.32 –1.11 – –

1950 13 11 8 3 19.7 62.1 160 100.4 955 964.0 –1.06 12 0 0 9.17 15.38 –0.12 0.14 Dog

1951 10 8 5 0 19.7 63.3 140 89.0 964 964.0 0.09 3 4 5 8.95 –0.69 –0.01 0.03 Easy

1952 7 6 3 1 16.4 63.9 130 92.9 934 976.7 –0.03 0 12 0 8.81 –2.28 –0.43 –0.25

1953 14 6 4 3 18.8 66.2 130 74.6 929 979.3 0.42 0 12 0 9.87 –6.80 –0.02 –0.27

1954 11 8 2 3 21.8 69.7 120 75.5 937 973.3 –0.63 9 3 0 9.15 4.08 0.00 –0.42

1955 12 9 6 3 18.6 60.0 150 92.1 914 951.4 –1.24 12 0 0 9.49 10.58 –0.40 –0.44 Janet

1956 8 4 2 1 22.0 79.4 120 73.8 954 986.9 –0.80 12 0 0 9.37 10.73 –0.04 –0.84

1957 8 3 2 1 23.6 75.7 135 72.5 945 979.0 0.69 1 2 9 9.83 –3.89 –0.20 –0.53

1958 10 7 5 1 17.8 59.8 140 89.5 934 977.0 0.61 0 6 6 9.45 –3.20 –0.59 0.20 Cleo

1959 11 7 2 3 24.5 75.9 120 71.4 950 987.4 –0.06 0 12 0 10.20 –0.04 0.35 0.11

1960 7 4 2 2 21.4 71.2 140 82.1 932 971.7 –0.19 0 12 0 9.44 3.83 –0.41 0.06 Donna; Ethel

1961 11 8 7 1 19.5 61.5 150 97.7 920 957.0 –0.23 0 12 0 9.58 0.80 0.04 0.45 Carla; Hattie

1962 5 3 1 0 22.7 57.4 100 75.0 968 974.8 –0.47 4 8 0 8.76 5.40 –0.34 –0.54

1963 9 7 2 1 19.7 60.1 125 81.1 944 979.1 0.40 1 5 6 8.57 –1.95 –0.42 –0.27

1964 12 6 6 4 19.8 62.9 135 82.1 941 972.0 –0.62 9 2 1 9.49 6.28 –0.04 –0.05

1965 6 4 1 1 22.8 63.5 135 76.7 941 973.3 0.64 1 4 7 8.82 –8.43 –0.13 –0.60

1966 11 7 3 2 20.9 57.4 130 74.1 929 983.6 0.26 0 8 4 9.38 –4.24 –0.33 –0.11

1967 8 6 1 1 20.1 56.3 140 79.4 923 976.0 –0.35 1 11 0 9.40 3.20 0.37 –0.33 Beulah

1968 8 5 0 1 27.1 72.9 75 63.8 965 986.1 –0.03 4 6 2 9.32 3.02 –0.94 –0.09

1969 18 12 5 2 24.0 65.5 165 80.0 905 979.4 0.69 0 2 10 8.93 –5.38 –0.06 –0.11 Camille

1970 10 5 2 1 24.4 74.1 110 72.5 945 986.0 –0.36 6 5 1 9.28 3.93 –0.25 0.27

1971 13 6 1 3 25.1 69.3 140 70.4 943 984.9 –0.95 12 0 0 9.72 10.95 0.01 –0.68

1972 7 3 0 1 32.2 67.5 90 65.0 944 982.6 0.84 1 3 8 8.74 –7.35 0.51 –0.41 Edith

1973 8 4 1 0 22.8 63.8 100 68.8 962 982.3 –0.64 8 1 3 9.33 7.28 –0.09 0.11

1974 11 4 2 1 24.7 69.5 130 67.7 928 990.1 –0.97 12 0 0 8.94 9.90 0.18 –0.33

1975 9 6 3 1 27.7 61.8 120 83.9 939 971.9 –1.14 12 0 0 9.69 13.60 –0.07 –0.46

1976 10 6 2 1 25.0 65.2 105 70.5 957 982.1 –0.15 5 3 4 9.33 1.11 0.19 –1.04
8

Year NTC NH NMH NUSLFH

GL

PWS <PWS> LP <LP> <ONI> NLNM NNM NENM <AT> <SOI> <NAO> <EA> Comment <Lat> <Long>

1977 6 5 1 1 28.1 77.4 150 79.2 926 982.2 0.45 0 6 6 8.92 –9.90 –0.34 0.37 Anita

1978 12 5 2 0 23.6 64.8 120 66.3 947 987.9 –0.15 0 11 1 9.21 –1.65 0.32 0.10

1979 9 6 2 3 20.5 63.2 150 76.1 924 977.4 0.16 0 12 0 8.35 –1.91 0.14 0.38 David

1980 11 9 2 1 23.8 54.1 165 83.2 899 976.1 0.14 0 12 0 9.11 –3.08 –0.41 0.05 Allen

1981 12 7 3 0 23.2 61.3 115 75.0 946 981.8 –0.32 0 12 0 9.09 1.80 –0.15 0.26

1982 6 2 1 0 23.8 70.7 115 71.3 950 983.2 0.95 0 4 8 9.43 –13.05 0.43 0.461983 4 3 1 1 28.6 75.9 100 72.5 963 985.5 0.47 0 6 6 9.77 –8.33 0.31 0.38

1984 13 5 1 1 25.3 63.0 115 61.9 949 988.8 –0.45 3 9 0 9.29 –0.11 0.25 –0.18

1985 11 7 3 6 25.2 71.6 125 78.2 920 977.4 –0.58 9 3 0 8.70 0.86 –0.18 0.36

1986 6 4 0 2 24.3 69.3 90 67.5 979 991.7 0.28 0 7 5 8.57 –2.38 0.50 0.51

1987 7 3 1 1 19.2 56.8 110 59.3 958 992.1 –1.29 0 0 12 9.07 –13.08 –0.12 0.28

1988 12 6 3 1 21.6 64.6 160 73.3 888 972.8 –0.83 8 2 2 9.65 7.82 –0.01 0.27 Gilbert

1989 11 7 2 3 18.1 56.8 135 78.6 923 976.5 –0.63 5 7 0 10.07 6.77 0.70 0.19

1990 14 8 1 0 19.7 52.2 105 65.4 956 986.9 0.25 0 12 0 9.93 –2.19 0.59 0.33

1991 8 4 2 1 27.4 62.2 115 68.1 946 980.6 0.80 0 4 8 9.42 –8.78 0.27 –0.11

1992 7 4 1 1 27.4 58.6 150 81.4 922 974.4 0.76 0 5 7 9.45 –10.38 0.58 0.25 Andrew1993 8 4 1 1 20.4 63.1 100 61.3 960 986.9 0.47 0 12 0 9.27 –9.47 0.18 –0.27

1994 7 3 0 0 18.3 62.1 95 65.0 972 989.6 0.62 0 4 8 9.32 –11.93 0.58 0.79

1995 19 11 5 2 18.8 61.7 130 76.3 919 973.4 0.08 4 5 3 10.22 –2.27 –0.08 –0.31

1996 13 9 6 2 16.2 62.3 125 80.4 933 971.1 –0.29 3 9 0 9.22 5.69 –0.21 0.10

1997 8 3 1 1 27.0 70.5 110 56.3 946 990.8 1.26 0 4 8 10.32 –11.67 –0.16 0.30

1998 14 10 3 3 19.2 57.5 155 83.2 905 971.4 0.09 6 1 5 10.09 –1.08 –0.48 0.93 Mitch

1999 12 8 5 3 17.5 64.1 135 91.3 921 964.7 –1.06 12 0 0 10.18 7.95 0.39 0.25

2000 15 8 3 0 20.8 62.2 120 71.3 941 979.5 –0.74 9 3 0 9.93 7.80 0.21 0.59

2001 15 9 4 0 22.2 63.4 125 75.6 934 979.5 –0.12 2 10 0 9.57 0.53 –0.18 0.75

2002 12 4 2 1 26.2 69.9 125 65.0 934 984.6 0.78 0 4 8 10.20 –6.10 0.04 0.85

2003 16 7 3 2 22.0 64.0 145 70.3 915 981.8 0.48 0 9 3 10.02 –3.14 0.10 0.84 Isabel

2004 15 9 6 6 19.7 57.4 145 82.3 912 971.7 0.56 0 5 7 10.21 –4.82 0.24 0.15 Ivan

2005 28 15 7 6 22.5 66.8 160 76.8 882 974.4 0.21 0 10 2 10.24 –3.63 –0.27 0.45 Emily; Katrina; Rita; Wilma

2006 10 5 2 0 21.9 56.6 105 68.5 955 981.2 0.25 0 7 5 10.43 –1.93 –0.21 0.84

2007 15 7 2 1 22.1 64.7 150 68.3 907 981.9 –0.30 4 7 1 10.59 1.45 0.17 0.45 Dean

2008 16 9 5 3 19.9 63.0 125 78.4 935 976.9 –0.56 5 7 0 9.78 10.17 –0.38 0.37

Table 1. Summary of yearly values for North Atlantic basin tropical cyclones (Continued).
9

Table 2. Summary of 10-yma values for North Atlantic basin tropical cyclones.

Year NTC NH NMH NUSLFH

GL

PWS <PWS> LP <LP> <AT> <ONI> <SOI> <NAO> <EA> <LAT> <LONG>

1950 10.4 6.7 3.7 2.3 19.5 68.2 131.5 80.5 949.1 973.0 9.43 – 1.06 – –

1951 10.5 7.0 3.9 2.3 19.5 67.3 133.3 82.0 946.2 972.4 9.39 – 2.23 – –

1952 10.6 6.9 3.9 2.2 19.7 67.3 133.3 82.5 945.0 973.3 9.43 – 2.79 – –

1953 10.6 6.9 4.0 2.0 19.8 67.1 134.3 83.0 943.5 973.5 9.45 – 2.38 – –

1954 10.5 6.9 4.0 1.9 20.0 67.1 135.0 83.3 941.8 973.5 9.44 – 2.33 – –

1955 10.1 6.6 3.6 1.9 20.4 68.1 133.5 82.3 940.5 974.3 9.44 –0.16 1.81 –0.16 –0.23

1956 9.9 6.2 3.4 1.9 20.5 68.4 133.0 81.8 937.1 974.3 9.49 –0.13 1.31 –0.17 –0.21

1957 9.8 6.1 3.4 1.9 20.8 68.0 132.0 81.3 936.6 973.9 9.52 –0.17 1.77 –0.17 –0.21

1958 9.5 6.0 3.2 1.7 21.1 67.4 130.3 80.7 939.1 973.8 9.45 –0.19 2.39 –0.18 –0.22

1959 9.3 5.9 3.3 1.7 21.1 66.7 130.8 81.4 940.0 973.7 9.40 –0.19 2.74 –0.20 –0.20

1960 9.0 5.6 3.3 1.6 21.2 66.6 130.8 81.0 941.6 974.7 9.38 –0.10 1.90 –0.19 –0.19

1961 8.9 5.5 3.1 1.6 21.3 65.6 130.5 80.2 941.7 975.7 9.35 0.05 0.20 –0.19 –0.16

1962 9.0 5.8 3.1 1.6 21.1 63.6 131.3 80.6 939.3 975.3 9.33 0.05 –0.19 –0.18 –0.12

1963 8.9 5.9 2.8 1.6 21.4 63.3 128.3 79.6 939.8 975.6 9.30 –0.03 0.48 –0.17 –0.12

1964 9.2 6.0 2.7 1.6 21.8 63.4 127.3 78.8 939.1 975.7 9.23 –0.03 0.52 –0.21 –0.15

1965 9.7 6.3 2.8 1.5 22.0 63.0 128.0 78.7 937.5 976.0 9.16 0.00 0.26 –0.22 –0.15

1966 9.9 6.2 2.5 1.5 22.4 63.6 126.0 76.9 939.3 978.1 9.16 –0.04 0.77 –0.21 –0.19

1967 10.1 6.1 2.2 1.7 23.1 64.4 125.0 75.0 939.2 979.9 9.17 –0.01 0.64 –0.17 –0.24

1968 10.2 6.0 2.1 1.7 23.8 65.1 123.3 73.9 938.9 980.5 9.20 0.00 0.46 –0.11 –0.22

1969 10.1 5.7 1.8 1.5 24.2 65.7 121.8 72.6 939.2 981.5 9.21 –0.07 1.11 –0.08 –0.21

1970 10.2 5.7 1.7 1.3 24.7 65.8 120.8 72.2 938.4 982.4 9.23 –0.18 2.39 –0.07 –0.22

1971 10.3 5.8 1.8 1.3 25.1 66.2 118.8 72.4 939.7 982.2 9.27 –0.29 3.76 –0.04 –0.26

1972 10.1 5.7 1.7 1.2 25.7 67.6 118.0 72.2 941.3 982.5 9.24 –0.27 3.37 –0.05 –0.27

1973 10.2 5.6 1.8 1.2 25.9 68.3 120.8 72.3 940.5 982.9 9.21 –0.23 2.48 –0.02 –0.23

1974 10.0 5.3 1.8 1.2 25.6 67.8 122.3 72.2 940.6 982.8 9.18 –0.26 2.42 0.05 –0.19

1975 9.6 5.2 1.6 1.2 25.4 66.7 124.3 72.6 939.2 982.2 9.14 –0.27 2.25 0.05 –0.18

1976 9.6 5.5 1.7 1.1 25.3 65.3 125.8 73.3 937.1 981.6 9.10 –0.21 1.44 0.04 –0.14

1977 9.5 5.5 1.9 0.9 24.7 65.0 125.8 73.9 937.5 981.5 9.11 –0.17 0.70 0.02 –0.05

1978 9.2 5.4 1.9 0.9 24.6 65.8 127.0 74.4 937.9 981.7 9.16 –0.11 –0.37 0.04 0.00

1979 9.1 5.4 1.9 0.9 24.9 66.1 126.3 74.3 939.0 981.8 9.20 –0.03 –1.65 0.06 0.02

1980 9.3 5.5 1.8 1.2 24.8 66.2 125.8 73.7 939.1 982.0 9.17 0.02 –2.79 0.06 0.07

1981 9.2 5.4 1.7 1.5 24.7 66.9 125.3 73.3 939.2 982.7 9.08 0.07 –3.60 0.07 0.19
10

Year NTC NH NMH NUSLFH

GL

PWS <PWS> LP <LP> <AT> <ONI> <SOI> <NAO> <EA> <LAT> <LONG>

1982 9.1 5.2 1.6 1.5 24.2 66.1 122.5 72.1 941.9 983.7 9.05 0.14 –3.93 0.10 0.26

1983 9.1 5.2 1.7 1.6 23.7 65.1 122.5 71.5 940.6 983.4 9.08 0.15 –3.62 0.09 0.27

1984 9.2 5.3 1.7 1.6 23.4 64.7 124.0 72.0 937.6 982.6 9.19 0.07 –2.71 0.10 0.27

1985 9.5 5.3 1.7 1.6 23.1 64.3 120.5 71.2 940.4 983.1 9.32 0.04 –2.23 0.18 0.27

1986 9.4 5.1 1.6 1.6 23.1 64.3 117.5 70.0 943.2 983.6 9.37 0.10 –2.72 0.25 0.27

1987 9.3 5.0 1.5 1.7 23.5 63.7 119.3 70.1 941.8 983.1 9.39 0.15 –3.11 0.28 0.24

1988 9.5 5.2 1.5 1.7 23.3 62.5 121.0 70.1 940.3 982.7 9.37 0.14 –3.04 0.28 0.20

1989 9.4 5.1 1.5 1.7 22.5 61.8 120.0 69.6 941.3 982.9 9.34 0.19 –3.69 0.29 0.21

1990 9.5 5.2 1.5 1.4 21.8 61.2 119.3 69.7 942.4 982.7 9.42 0.28 –4.43 0.31 0.23

1991 10.3 5.7 1.9 1.2 21.1 60.4 121.3 70.3 940.0 981.5 9.53 0.28 –4.19 0.28 0.17

1992 10.7 5.9 2.2 1.2 21.1 60.7 123.0 70.8 937.1 980.4 9.62 0.25 –3.71 0.25 0.15

1993 10.8 6.1 2.2 1.3 21.4 61.1 122.8 71.1 937.4 980.2 9.71 0.30 –4.09 0.22 0.19

1994 11.0 6.4 2.4 1.4 21.2 61.1 122.3 72.2 938.1 979.6 9.74 0.32 –4.47 0.18 0.22

1995 11.1 6.4 2.6 1.4 21.2 61.9 122.8 73.2 937.3 978.6 9.74 0.25 –3.91 0.15 0.24

1996 11.5 6.7 2.8 1.4 21.0 62.5 124.0 73.8 935.9 978.2 9.75 0.15 –2.95 0.11 0.30

1997 12.1 6.9 3.0 1.3 20.7 63.1 123.3 73.4 935.9 978.6 9.79 0.11 –2.27 0.06 0.37

1998 12.7 7.1 3.1 1.4 20.7 63.7 124.3 73.0 934.3 978.9 9.87 0.11 –1.74 0.03 0.45

1999 13.5 7.5 3.5 1.7 20.9 63.5 129.0 74.3 929.0 977.7 9.95 0.11 –1.07 0.00 0.48

2000 14.4 8.0 3.9 2.2 21.1 63.6 133.0 75.2 924.2 976.9 10.00 0.11 –0.78 –0.02 0.48

2001 14.7 8.0 3.8 2.3 21.6 63.5 133.5 74.7 923.4 977.5 10.06 0.14 –1.23 –0.03 0.56

2002 14.9 8.0 3.7 2.2 21.7 63.0 134.5 74.7 922.6 977.5 10.13 0.09 –0.95 –0.02 0.60

2003 15.3 8.2 3.8 2.2 21.4 62.9 135.0 75.0 922.1 977.3 10.13 –0.02 0.27 0.01 0.58

Table 2. Summary of 10-yma values for North Atlantic basin tropical cyclones (Continued).
11

Table 3. Poisson distributions for NTC, NH, NMH, and NUSLFH based on 1950–2008 statistics.

Events NTC (m=10.8) NH (m=6.3) NMH (m=2.7) NUSLFH (m=1.6)

r f P(r) f P(r) f P(r) f P(r)

0 0 0.00002 0 0.00184 4 0.06721 11 0.20190

1 0 0.00022 0 0.01157 14 0.18145 26 0.32303

2 0 0.00119 1 0.03644 17 0.24496 7 0.25843

3 0 0.00428 7 0.07653 9 0.22047 11 0.13783

4 1 0.01156 10 0.12053 2 0.14882 1 0.05513

5 1 0.02498 6 0.15187 6 0.08036 0 0.01764

6 4 0.04496 9 0.15946 4 0.03616 3 0.00470

7 6 0.06937 9 0.14352 2 0.01395

8 8 0.09365 6 0.11302 1 0.00471

9 3 0.11238 6 0.07911 0 0.00141

10 5 0.12137 1 0.04984 0 0.00038

11 8 0.11916 2 0.02855 0 0.00009

12 7 0.10724 1 0.01499 0 0.00002

13 4 0.08909 0 0.00726 0 0.00000

14 3 0.06873 0 0.00327

15 4 0.04949 1 0.00137

16 2 0.03340 0 0.00054

17 0 0.02122 0 0.00020

18 1 0.01273 0 0.00007

19 1 0.00724 0 0.00002

20 0 0.00391 0 0.00001

21 0 0.00201 0 0.00000

22 0 0.00099

23 0 0.00046

24 0 0.00021

25 0 0.00009

26 0 0.00004

27 0 0.00001

28 1 0.00001

29 0 0.00000

Note: m is the mean and P(r) is the probability of r events occurring.
12

Table 4. Frequency of U.S. land strikes by state.

State

Interval

1950–1965 1966–1994 1995–2008 Total Percent

AL 1 3 5 9 5.7

CT 2 3 0 5 3.1

FL 11 13 21 45 28.3

GA 0 2 0 2 1.3

LA 4 9 8 21 13.2

MA 2 1 0 3 1.9

MD 1 0 0 1 0.6

ME 3 2 0 5 3.1

MS 1 3 2 6 3.8

NC 8 6 8 22 13.8

NH 1 1 0 2 1.3

NY 2 4 0 6 3.8

RI 2 1 0 3 1.9

SC 4 3 2 9 5.7

TX 4 8 6 18 11.3

VA 1 0 1 2 1.3

Total 47 59 53 159 100.1*

*Total percent exceeds 100% because of roundoff error.

Table 5. Listing of U.S. land-falling hurricanes.

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP USLFH

1945 715 Unnamed MH 06/20 17.5 85.7 100 – FL1

719 Unnamed MH 08/24 19.4 94.0 120 966 TX2

723 Unnamed MH 09/12 19.0 56.6 120 951 FL3

1946 730 Unnamed MH 10/05 18.0 87.2 115 979 FL1

1947 734 Unnamed H 08/18 24.0 80.0 70 – TX1

735 Unnamed MH 09/04 14.5 20.1 140 947 FL4, LA3, MS3, FL2

739 Unnamed H 10/09 15.4 82.0 75 973 GA2, SC2, FL1

1948 745 Unnamed H 09/01 23.8 94.7 70 989 LA1

747 Unnamed MH 09/18 18.2 78.8 105 963 FL3, FL2

748 Unnamed MH 10/03 15.3 81.8 115 975 FL2

1949 750 Unnamed H 08/21 21.3 62.6 95 977 NC1

751 Unnamed MH 08/23 18.2 60.0 130 954 FL3

759 Unnamed MH 09/27 13.3 90.1 115 – TX2

1950 764 Baker MH 08/20 16.3 55.0 105 979 AL1

767 Easy MH 09/01 19.1 84.1 110 958 FL3

773 King MH 10/13 16.0 84.2 105 955 FL3

1952 787 Able H 08/24 16.4 51.2 90 998 SC1
13

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP USLFH

1953 794 Barbara H 08/11 22.8 73.9 95 987 NC1

796 Carol MH 08/31 10.6 37.7 130 929 ME1

800 Florence MH 09/23 16.9 75.8 110 968 FL1

1954 809 Carol H 08/25 25.1 75.5 85 976 NY3, CT3, RI3, NC2

811 Edna MH 09/04 19.3 62.8 105 – MA3, ME1

815 Hazel MH 10/05 12.4 59.2 120 937 SC4, NC4, MD2

1955 819 Connie MH 08/03 15.7 39.2 125 936 NC3, VA1

820 Diane MH 08/09 18.9 54.3 105 969 NC1

826 Ione MH 09/10 15.4 44.2 105 938 NC3

1956 836 Flossy H 09/22 22.2 89.8 80 980 LA2, FL1

1957 839 Audrey MH 06/25 21.6 93.3 125 946 TX4, LA4

1958 853 Helene MH 09/23 22.5 64.8 115 934 NC3

1959 859 Cindy H 07/07 31.5 77.1 65 – SC1

860 Debra H 07/23 27.5 93.1 75 984 TX1

863 Gracie MH 09/22 21.8 74.1 120 950 SC3

1960 871 Donna MH 08/30 10.3 26.9 140 932 FL4, NC3, NY3, FL2, CT2, RI2, MA1, NH1, ME1

872 Ethel MH 09/14 23.9 90.6 140 981 MS1

1961 876 Carla MH 09/05 16.3 82.7 150 931 TX4

1963 893 Cindy H 09/16 26.7 93.7 70 996 TX1

1964 903 Cleo MH 08/21 13.7 49.1 135 950 FL2

904 Dora MH 09/01 11.7 47.0 115 942 FL2

908 Hilda MH 09/29 22.0 84.2 130 941 LA3

909 Isbell MH 10/13 20.0 85.0 110 964 FL2, FL2

1965 913 Betsy MH 08/29 19.2 63.4 135 941 FL3, LA3

1966 917 Alma MH 06/06 18.1 84.2 110 970 FL2

925 Inez MH 09/24 14.8 48.7 130 929 FL1

1967 929 Beulah MH 09/07 13.9 60.8 140 923 TX3

1968 943 Gladys H 10/15 19.4 83.3 75 965 FL2, FL1

1969 946 Camille MH 08/14 19.4 82.0 165 905 LA5, MS5

950 Gerda MH 09/08 29.7 79.7 110 979 ME1

1970 964 Celia MH 08/01 23.3 85.8 110 945 TX3

1971 977 Edith MH 09/07 12.7 69.1 140 943 LA2

978 Fern H 09/08 26.9 92.6 80 978 TX1

979 Ginger H 09/10 27.7 66.1 95 959 NC1

1972 986 Agnes H 06/16 20.0 86.2 75 978 FL1, NY1, CT1

1974 1005 Carmen MH 08/30 17.0 67.4 130 928 LA3

1975 1015 Eloise MH 09/16 19.0 65.6 110 955 FL3, AL1

1976 1022 Belle MH 08/07 25.6 73.2 105 957 NY1

1977 1031 Babe H 09/03 27.6 88.5 65 995 LA1

1979 1049 Bob H 07/10 23.5 93.8 65 986 LA1

1051 David MH 08/26 11.6 42.2 150 924 FL2, FL2, GA2, SC2

1053 Frederic MH 08/30 11.5 36.0 115 943 AL3, MS3

1980 1057 Allen MH 08/02 11.0 42.8 165 899 TX3

Table 5. Listing of U.S. land-falling hurricanes (Continued).
14

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP USLFH

1983 1086 Alicia MH 08/15 27.2 91.0 100 963 TX3

1984 1094 Diana MH 09/08 28.5 77.4 115 949 NC2

1985 1104 Bob H 07/22 26.2 83.8 65 1002 SC1

1106 Danny H 08/14 23.7 87.8 80 988 LA1

1107 Elena MH 08/28 22.6 80.0 110 953 AL3, MS3, FL3

1109 Gloria MH 09/17 14.6 28.3 125 920 NC3, NY3, CT2, NH2, ME1

1112 Juan H 10/26 23.8 92.5 75 971 LA1

1113 Kate MH 11/15 21.1 63.8 105 954 FL2, GA1

1986 1115 Bonnie H 06/24 26.6 89.5 75 992 TX1

1116 Charley H 08/15 32.2 78.5 70 980 NC1

1987 1126 Floyd H 10/10 16.0 82.2 65 993 FL1

1988 1133 Florence H 09/07 22.7 90.2 70 983 LA1

1989 1141 Chantal H 07/31 25.4 91.0 70 984 TX1

1146 Hugo MH 09/11 12.5 29.2 135 923 SC4, NC1

1148 Jerry H 10/13 20.4 93.0 75 983 TX1

1991 1165 Bob MH 08/16 26.4 75.8 100 950 NY2, CT2, RI2, MA2

1992 1173 Andrew MH 08/17 12.3 42.0 150 922 FL5, FL4, LA3

1993 1183 Emily MH 08/25 28.0 60.4 100 960 NC3

1995 1198 Erin H 07/31 22.3 73.2 80 974 FL1, FL2

1208 Opal MH 09/30 21.1 88.5 130 919 FL3, AL1

1996 1214 Bertha MH 07/05 11.0 39.0 100 960 NC2

1218 Fran MH 08/27 14.6 44.9 105 946 NC3

1997 1230 Danny H 07/17 28.3 91.4 70 984 LA1, AL1

1998 1235 Bonnie MH 08/20 17.3 57.3 100 954 NC2

1238 Earl H 08/31 22.4 93.8 85 964 FL1

1240 Georges MH 09/16 10.6 31.3 135 937 FL2, MS2

1999 1249 Bret MH 08/19 19.8 94.7 125 944 TX3

1253 Floyd MH 09/08 15.3 48.2 135 921 NC2

1256 Irene H 10/13 18.5 83.4 95 960 FL1

2002 1301 Lili MH 09/23 12.1 54.6 125 940 LA1

2003 1304 Claudette H 07/07 13.2 59.8 75 982 TX1

1310 Isabel MH 09/06 13.9 32.7 145 915 NC2, VA1

2004 1318 Alex MH 08/01 31.6 79.2 105 957 NC1

1320 Charley MH 08/10 12.9 65.3 125 947 FL4, FL1, FL1, SC1, NC1

1323 Frances MH 08/25 11.5 39.8 125 937 FL2, FL1

1324 Gaston H 08/28 31.3 78.2 65 986 SC1

1326 Ivan MH 09/03 9.7 30.3 145 912 AL3, FL3

1327 Jeanne MH 09/14 16.4 62.6 105 951 FL3, FL1, FL1

Table 5. Listing of U.S. land-falling hurricanes (Continued).
15

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP USLFH

2005 1335 Cindy H 07/05 25.1 90.2 65 992 LA1

1336 Dennis MH 07/05 13.0 65.9 130 930 FL3, AL1

1343 Katrina MH 08/24 24.5 76.5 150 902 FL1, FL1, LA3, MS3, AL1

1347 Ophelia H 09/07 27.9 78.8 75 976 NC1

1349 Rita MH 09/18 22.2 72.3 155 897 FL1, LA3, TX2

1354 Wilma MH 10/17 16.9 79.6 160 882 FL3, FL2

2007 1378 Humberto H 09/12 27.8 95.1 80 985 TX1, LA1

2008 1389 Dolly H 07/20 17.8 83.6 85 964 TX1

1392 Gustav MH 08/25 15.1 69.6 125 943 LA2

1394 Ike MH 09/01 17.3 38.4 125 935 TX2, LA1

Table 5. Listing of U.S. land-falling hurricanes (Continued).
16

1950 1960 1970 1980 1990 2000

 m = 64.5 W

sd = 6.1

50

55

60

65

70

75

80

85

(b)

Year

<LONG>

 m = 22.3 N

sd = 3.4

15

20

25

30

35

(a)

1950–2008

<LAT>

Figure 2. Yearly variation of (a) <LAT> and (b) <LONG> for the interval 1950–2008.

representing their 10-yma values. For 1950–2008, <LAT> and <LONG> measures, respectively, 

about 22.3° N. and about 64.5° W. Values lying above the means suggest more tropical cyclones originating at higher northerly latitudes and more westerly longitudes (i.e., closer to the United States) 

than values lying below the means. It appears that the 1950s saw more tropical cyclones, on average, forming in the deeper tropics and closer to the United States than other times. Also, the 1970s 

apparently saw more tropical cyclones forming at higher northern latitudes and closer to the United 

States than other times. Since the 1990s, however, although there has been a return to deeper tropical 

latitudes, on average, the tropical cyclones appear to be forming farther away from the United States, 

based on <LONG>.
17

Figure 3 combines the two plots into a single plot of the centroid variation using the 10-yma 

values. The vertical and horizontal thin lines are the parametric means. The years 1950, 1960, 1970, 

1980, 1990, and 2000 are marked by filled circles. The year 2003 (the last 10-yma parametric value 

available year) is marked by a filled square. Time moves along the dotted line. Thus, the 1950s can 

be characterized as always being in the lower-left quadrant (meaning lower northerly latitude and 

more westerly longitude). The 1960s are seen to transition from the lower-left quadrant, first to the 

lower-right quadrant, then to the upper-left quadrant (meaning a lower northerly latitude and more 

westerly longitude, first transitioning to lower northerly latitude and less westerly longitude, then 

to more northerly latitude and less westerly longitude, and finally to more northerly latitude and 

more westerly longitude). The 1970s can be characterized as always being in the upper-left quadrant 

(meaning more northerly latitude and more westerly longitude). The 1980s are seen to transition 

from the upper-left quadrant to the lower-right quadrant (meaning a transition from more northerly latitude and more westerly longitude to lower northerly latitude and less westerly longitude). 

The 1990s through 2003 can be characterized as always being in the lower-right quadrant (meaning 

lower northerly latitude and less westerly longitude). It may be that the eastward drift in longitude 

associated with North Atlantic basin tropical cyclones might simply be related to better observations 

because of the use of satellites beginning in the 1970s. Certainly, the current high-activity interval, 

while reflecting a deeper tropics origin for tropical cyclones, which was also seen in the 1950s, remains 

several degrees farther eastward than was seen in the 1950s.

Table 6 gives the proportion of NUSLFH to NH based on GL, divided into 5° latitudinal and 

longitudinal bins. For convenience, across the bottom of the table, the proportions have been crudely 

grouped according to geographic areas. (See table 13 in the appendix.) For example, group 1, which 

covers the Gulf of Mexico area, marks the GL for 51 tropical cyclones that became hurricanes at 

some point in their development (in total, 132 tropical cyclones formed in the group 1 area, or about 

20.7% of the total). Of these 51 hurricanes, 27 struck the United States as a hurricane. Thus, 27/51, 

or 52.9% of the tropical cyclones that originated in the Gulf of Mexico area and that became hurricanes, struck the United States as hurricanes. The 27 U.S. land-falling hurricanes represent 28.4% 

of all NUSLFH (27/95), and the 51 tropical cyclones of group 1 that became hurricanes represent 

13.7% of all hurricanes (51/371).

Group 2 represents the Caribbean Sea area. Some 63 tropical cyclones originated in the 

Caribbean that later became hurricanes (in total, 86 tropical cyclones formed in the group 2 area, 

or ≈13.5% of the total). Of the 63, 21 struck the United States (33.3%) as hurricanes. Of the 95 U.S. 

land-falling hurricanes, group 2 accounts for 22.1%, and of the 371 hurricanes, group 2 accounts for 

17%.

Group 3 represents the eastern seaboard area. Some 83 tropical cyclones originated in this 

area that later became hurricanes (in total, 157 tropical cyclones formed in the group 3 area, or about 

24.6% of the total). Of the 83, 19 struck the United States (22.9%) as hurricanes. Of the 95 U.S. landfalling hurricanes, group 3 accounts for 20%, and of the 371 hurricanes, group 3 accounts for 22.4%.

Group 4 represents the lower North Atlantic-Cape Verde area. Some 125 tropical cyclones 

originated in this area that later became hurricanes (in total, 176 tropical cyclones formed 

in the group 4 area, about 27.5% of the total). Of the 125, 28 struck the United States (22.4%) 
18

70

1985 and 1986

1962 and 2000

1990

1960

1950

2003

1980 1970

69 68 67 66 65 64 63 62 61 60

2625242322212019

<10–yma W. LONG>

<10-yma N. LAT>

Figure 3. Yearly variation of the centroid location of North Atlantic basin tropical cyclones.
19

Table 6. Proportion: NUSLFH/NH for 1950–2008 (based on GL).

W. Longitude

N. Latitude

44.9–40.0 39.9–35.0 34.9–30.0 29.9–25.0 24.9–20.0 19.9–15.0 14.9–10.0 9.9–5.0 Total

99.9–95.0 1/1 0/2 1/3

94.9–90.0 7/7 7/15 1/1 15/23

89.9–85.0 2/5 6/13 0/2 8/20

84.9–80.0 1/3 2/4 9/20 0/7 12/34

79.9–75.0 4/8 5/10 1/2 2/5 0/2 12/27

74.9–70.0 0/3 0/8 1/7 4/8 0/1 0/2 5/29

69.9–65.0 0/7 1/9 0/3 3/5 3/7 7/31

64.9–60.0 0/1 0/5 1/5 2/7 3/7 1/5 7/30

59.9–55.0 0/3 0/2 0/3 0/4 0/4 2/9 2/7 4/32

54.9–50.0 0/3 0/3 0/4 2/8 1/9 3/27

49.9–45.0 0/1 0/4 0/1 0/5 1/6 4/15 5/32

44.9–40.0 0/1 0/1 0/2 1/3 3/11 4/18

39.9–35.0 0/1 0/2 2/5 4/13 6/21

34.9–30.0 0/1 0/1 0/4 2/12 1/1 3/19

29.9–25.0 0/1 0/1 3/11 3/13

24.9–20.0 0/1 0/1 0/2 0/7 0/11

19.9–15.0 0/1 0/1

Total 0/3 0/10 4/41 19/56 22/72 26/79 23/109 1/1 95/371

Group 1 (Gulf of Mexico area):* 27/51 (27/51=52.9%, 27/95=28.4%, 51/371=13.7%)

Group 2 (Caribbean Sea area):** 21/63 (21/63=33.3%, 21/95=22.1%, 63/371=17.0%)

Group 3 (East coast area):*** 19/83 (19/83=22.9%, 19/95=20.0%, 83/371=22.4%)

Group 4 (Lower N. Atlantic–Cape Verde area):† 28/125 (28/125=22.4%, 28/95=29.5%, 125/371=33.7%)

Group 5 (Open N. Atlantic area):‡ 0/49 (0/49=0.0%, 0/95=0.0%, 49/371=13.2%)

Total: 95/371

Notes:

 *18.0N–30.0N, 80.0W–99.9W and 15.0–19.9N, 90.0–94.9W

 **10.0N–19.9N, 60.0W–89.9W

***20.0N–39.9N, 60.0W–79.9W

 †5.0N–19.9N, 15.0W–59.9W

 ‡20.0N–44.9N, 15.0W–59.9W

as hurricanes. Of the 95 USLFH, group 4 accounts for 29.5%, and of the 371 hurricanes, group 4 

accounts for 33.7%.

Group 5 represents the open North Atlantic area. Some 49 tropical cyclones originated 

in this area that later became hurricanes (in total, 88 tropical cyclones formed in the group 5 area). 

Of the 49, none struck the United States as hurricanes, and of the 371 hurricanes, group 5 accounts 

for 13.2%.

Obviously, tropical cyclones that initially form in the Gulf of Mexico, Caribbean Sea, and 

along the eastern seaboard, and that become hurricanes, are the most worrisome, since as a single 

group, they account for more than 70% of the U.S. land-falling hurricanes. Katrina, although it 
20

formed in the group 3 area, moved westward across Florida and into the Gulf of Mexico before 

striking Louisiana, Mississippi, and Alabama. Andrew, the second costliest hurricane to strike the 

U.S. mainland, originated in the group 4 area, which contains the largest single grouping of tropical 

cyclones.

The importance of table 6 is that during the 2009 hurricane season (or any future season), 

should a tropical cyclone that later becomes a hurricane form in a particular latitudinal-longitudinal 

bin, an estimate can easily be made regarding the likelihood of it striking the United States. As an 

example, should a tropical cyclone that later becomes a hurricane form in the group 1 area, specifically, in the latitudinal-longitudinal bin of 25° N.–29.9° N., 90° W.–94.9° W. (an area just off the 

Texas-Louisiana coast), past experience has shown that this has previously occurred seven times and, 

in every case, the tropical cyclone struck the U.S. coastline as a hurricane.

Figure 4 is a map of the North Atlantic basin, included to assist the reader in more clearly 

visualizing the construction of table 6. Tracking charts are available online at <http://www.nhc.noaa.

gov/tracking_charts.shtml>.22

During the first high-activity interval 1950–1965, the variation by group, respectively, from 

1 to 5 was 38-19-29-49-19. For the low-activity interval 1966–1994, the variation in numbers was 

56-29-86-68-38. For the current high-activity interval 1995–2008, it has been 38-38-42-59-51. For 

the combined high-activity intervals, it has been 76-57-71-108-50. It appears then that during the 

high-activity intervals, there is a general increase in tropical cyclone frequency throughout the North 

Atlantic basin, as compared to the low-activity interval. Only for the group 3 area are there more 

tropical cyclones forming during the low-activity interval than in the combined high-activity intervals. Perhaps, this is somehow related to the occurrences of EN, since the low-activity interval has 

more EN months than the combined high-activity intervals (95 versus 76), and the effect of EN 

would be to hinder formation of tropical cyclones in the lower tropics (i.e., in groups 2 and 4), 

thereby, allowing only higher latitudinal tropical cyclones to form.

Figure 5 displays the yearly variation in the number of tropical cyclone formations by group 

for the interval 1950–2008. The thin, horizontal lines represent the long-term means for each group. 

Figure 5(a) shows the yearly variation for group 1 (the Gulf of Mexico area). Some 132 tropical 

cyclones formed in this region between 1950 and 2008, with no formations occurring only twice, 1962 

and 1992. The peak number of group 1 area formations measures 5 and has occurred twice, in 1957 

and 2003. In 2008, only two tropical cyclones formed in the group 1 area, Edouard (August 4) and 

Marco (October 6), both only of tropical storm strength.

Figure 5(b) shows the yearly variation for group 2 (Caribbean Sea area). Some 86 tropical 

cyclones formed in this region during the interval 1950–2008, with no formations occurring during 

13 years, 9 of which occurred during the low-activity interval. The last no-formation year for the 

group 2 area was 1997, an EN year. The number during the current high-activity interval appears to 

have increased (true for all groups, not just group 2, even when compared to the first high-activity 

interval). The highest yearly number to date is 7 in 2005. In 2008, 6 tropical cyclones formed in the 

group 2 area, Arthur (May 31), Dolly (July 20), Fay (August 15), Gustav (August 25), Omar (October 14), and Paloma (November 6).
21

105° W. 100° W. 95° W. 90° W. 85° W. 80° W. 75° W. 70° W. 65° W. 60° W. 55° W. 50° W. 45° W. 40° W. 35° W. 30° W. 25° W. 20° W. 15° W.

105° W. 100° W. 95° W. 90° W. 85° W. 80° W. 75° W. 70° W. 65° W. 60° W. 55° W. 50° W. 45° W. 40° W. 35° W. 30° W. 25° W. 20° W. 15° W.

5° N.10° N.15° N.20° N.25° N.30° N.35° N.40° N.45° N.50° N.

5° N.

10° N.15° N.20° N.25° N.30° N.35° N.40° N.45° N.50° N.

Figure 4. Map of the North Atlantic basin hurricane tracking chart, National Hurricane Center, 

Miami, FL.
22

Figure 5(c) shows the yearly variation for group 3 (the east coast area). Some 157 tropical 

cyclones formed in this area, with no formations only occurring 5 times: 1950, 1955, 1965, 1989, and 

1994. The peak highest yearly number to date is 7 in 2005. In 2008, 2 tropical cyclones formed in the 

group 3 area: Cristobal (July 19) and Kyle (September 25).

Figure 5(d) shows the yearly variation for group 4 (the lower North Atlantic-Cape Verdi 

area). Some 176 tropical cyclones formed in this area, with no formations occurring only 3 times: 

1972, 1977, and 1983, these years associated with the occurrence of EN. The highest yearly number 

to date is 9 in 1995, the start of the current high-activity interval. In 2008, 3 tropical cyclones formed 

in the group 4 area: Bertha (July 3), Ike (September 1), and Josephine (September 2).

Figure 5(e) shows the yearly variation for group 5 (the open North Atlantic area). Some 88 

tropical cyclones formed in this area, with no formations occurring 14 times, 5 times during the first 

high-activity interval, 7 during the low-activity interval, and only twice during the current highactivity interval. The highest yearly number is 8 in 2005, well above its long-term average. In 2008, 

3 tropical cyclones formed in the group 5 area: Hanna (August 28), Laura (September 26), and Nana 

(October 12).

2.3 Peak Wind Speed and Lowest Pressure Variation

Figure 6 displays the yearly variation of PWS (fig. 6(a)) and <PWS> (fig. 6(b)). Its construction follows that of figures 1 and 2. Based on the 10-yma trend line, PWS is found to be higher than 

its long-term average (127.3 kt) in the 1950s, lower in the 1960s–1980s, and higher once again in 

the 1990s and 2000s. In fact, the 10-yma value for 2003 (135 kt) is found to equal the previous high 

10-yma value in 1954. Between 1998 and 2003, the 10-yma value for PWS has been higher every year 

than the preceding yearly value, increasing from 123.3 kt in 1997 to 135 kt in 2003, an increase of 

≈9.5%. Seven of 14 years in the span of 1995–2008 had yearly PWS in excess of its long-term average, 

with the lowest yearly PWS being 105 kt in 2006, a year in which EN occurred during the months of 

August–December.

The trend line for <PWS> follows closely that of PWS, although values have not yet risen 

above the long-term average (75.4 kt) in the current epoch, with current values (75 kt in 2003) paling 

in comparison to those seen in the 1950s (83.3 kt in 1954). As with yearly PWS, only 7 of the past 

14 years have had yearly <PWS> in excess of the long-term average, with the lowest yearly <PWS> 

being 56.3 kt in 1997, also a year dominated by EN (May–December).

Figure 7 shows the yearly variation of LP (fig. 7(a)) and <LP> (fig. 7(b)). Its construction 

follows that of figures 1, 2, and 6. The trend line for LP has consistently been above the long-term 

average (931.7 mb) until the 1990s, hovering at ≈940 mb. Since 1997, however, the trend line has 

fallen from 935.9 to 922.1 mb (in 2003), indicating a strengthening. As with PWS and <PWS>, 7 of 

the past 14 years have had LP below the long-term average (remember, LP varies inversely with PWS, 

so strengthening is indicated by lower LP and higher PWS, and weakening is indicated by higher LP 

and lower PWS), with 8 tropical cyclones having LP ≤ 920 mb during the current epoch, the lowest 

being Wilma in 2005, holding the record at 882 mb. The names of the strongest tropical cyclones 

(those having LP ≤ 925 mb) appear on the chart. The year 2005 is the only year to have more than 

a single tropical cyclone having LP ≤ 925 mb (Katrina, Rita, and Wilma).
23

1950 1960 1970 1980 1990 2000

m = 2.7

sd = 1.6

 m = 3.0sd = 2.1

 m

mean = 1.5 sd = 1.4

= 1.5

sd = 1.5 m= 2.2sd = 1.3

1010

55

10

5

10

5

(a)

(b)

Group 1 area (132 tropical cyclones)

Group 2 area (86 tropical cyclones)

Group 3 area (157 tropical cyclones)Group 4 area (176 tropical cyclones)

Group 5 area (88 tropical cyclones)

(c)

(d)

(e)

5

Year

Number Number Number Number Number

Figure 5. Yearly variation of the number of tropical cyclones in selected geographical areas: (a) Group 1 (Gulf 

of Mexico), (b) group 2 (Caribbean Sea), (c) group 3 (east coast), (d) group 4 (lower North AtlanticCape Verdi), and (e) group 5 (open North Atlantic).
24

1950 1960 1970 1980 1990 2000

m = 75.4 kt

sd = 9.3

100

50 (b)

Year

<PWS> (kt)

m = 127.3 kt

sd = 20.6

150100

50 (a)

PWS (kt)

1950–2008

Figure 6. Yearly variation of (a) PWS and (b) <PWS> for the interval 1950–2008.
25

1950 1960 1970 1980 1990 2000

1,000

920900

Janet

1950–2008

Hattie Beulah

Camille

David

Allen

Gloria

Gilbert

Hugo

Andrew Opal

Mitch

Isabel

Ivan

Dean

Wilma (also Katrina-902; Rita-897)

980960940880950

(a)

(b)

Year

LP (mb) <LP> (mb) m= 931.7 mb sd = 41.9 m= 978.8 mb sd = 8.2

Figure 7. Yearly variation of (a) LP and (b) <LP> for the interval 1950–2008. Also given are the names 

of the most powerful tropical cyclones (LP≤ 925 mb).
26

The trend line for <LP> appears to follow the inverse of <PWS>, as is to be expected. Lower 

<LP> is seen in the 1950s, higher <LP> in the 1960s–1980s, and lower <LP> again in the 1990s and 

2000s, although the <LP> during the current epoch (977.3 mb in 2003) remains higher than was seen 

in the 1950s (972.4 mb in 1951). Seven of the past 14 years have had yearly <LP> below the longterm average (978.8 mb), of similar behavior to PWS, <PWS>, and LP.

It should be noted that yearly pressures (LP and <LP>) are not as reliably determined as 

PWS and <PWS>, especially for years prior to the 1970s. During the early record, many of the tropical cyclones in the best tracks file, while having measurements of wind speed, more often than not, 

have no pressure determinations. So, figure 6 should be viewed with some caution, especially for the 

early years.

2.4 Effects of El Niño and La Niña

The warm EN phase of the ENSO phenomenon has long been recognized as having a dampening effect on the frequency of North Atlantic basin tropical cyclones.23 While apparently true, 

determination of a generally accepted, consistent listing of EN (and LN) events has often been lacking, because of the different methodologies used in the past to define them.

The ONI, based on the ERSST.v3b (replacing the ERSST.v3 in December 2008),24 has now 

become the de facto means whereby ENSO conditions are described. As noted in the Introduction, 

the ONI is updated monthly and is available online.2 When the ONI has at least a 5-mo continuous value of 5 °C or warmer, an EN is said to be occurring, while when the ONI has at least a 5-mo 

continuous value of –5 °C or cooler, a LN is said to be occurring. All other times are said to be representative of ENSO-neutral conditions.

Table 7 is a listing of EN and LN events based on the ONI using ERSST.v3b. Although having the same number of events as was listed in the previous publication1 (17 EN and 13 LN events), 

the listing has subtly changed. Some events have different start and/or end dates and some events 

have different maximum ONI values (thereby affecting their strength classification—W=weak, 

M=moderate, and S=strong).

Table 8 summarizes specific characteristics of the 17 EN and 13 LN events. For example, 

using the ERSST.v3b data set, on average, the duration of an EN from beginning to end is ≈10 mo, 

having an sd of ≈4 mo, and a range of 5 to 19 mo. The recurrence rate (from the end of an old EN 

event to the start of a new EN event) averages ≈32 mo, having an sd of ≈18 mo, and a range of 3 to 

64 mo. The last EN event ended in January 2007, more than 2 yr ago, so based on the average recurrence rate, one might expect another EN to occur soon. During an EN event, on average, 8 tropical 

cyclones form in the North Atlantic basin during the event, having an sd of ≈3.5 and a range of zero 

to 15 in number; ≈4 hurricanes form, having an sd of ≈2, and a range of zero to 9; ≈1.5 major hurricanes form, having an sd of ≈2 and a range of zero to 6; and ≈1 hurricane strikes the U.S. coastline, 

having an sd of ≈1 and a range of zero to 6.

Likewise, on average, the duration of a LN event from beginning to end is ≈15 mo, having an 

sd of ≈11 mo and a range of 5 to 37 mo. The recurrence rate (from the end of an old LN event to 
27

Table 7. Listing of EN and LN events based on ONI (ERSST.v3b).

Start End

Dur 

(mo) max ONI <ONI>

Event 

Type Strength

Sums

NTC NH NMH NUSLFH

B01–1950 03–1951 >15 –1.7 –1.06 LN S 13 11 8 3

08–1951 12–1951 5 0.8 0.70 EN W 9 7 4 0

04–1954 01–1957 34 –2.0 –0.98 LN S 31 21 10 9

04–1957 06–1958 15 1.7 0.99 EN S 9 3 2 1

09–1962 01–1963 5 –0.7 –0.62 LN W 3 2 1 0

07–1963 01–1964 7 1.0 0.86 EN M 9 7 2 1

04–1964 01–1965 10 –1.2 –0.93 LN M 12 6 6 4

06–1965 04–1966 11 1.6 1.12 EN S 6 4 1 1

12–1967 04–1968 5 –0.9 –0.72 LN W 0 0 0 0

11–1968 06–1969 8 1.0 0.79 EN M 0 0 0 0

09–1969 01–1970 5 0.8 0.66 EN W 12 8 2 1

07–1970 01–1972 19 –1.3 –0.91 LN M 22 10 3 4

05–1972 03–1973 11 2.1 1.32 EN S 7 3 0 1

05–1973 05–1976 37 –2.1 –1.11 LN S 29 14 6 2

09–1976 02–1977 6 0.8 0.63 EN W 3 2 0 0

09–1977 01–1978 5 0.7 0.64 EN W 6 4 0 1

05–1982 06–1983 14 2.3 1.39 EN S 6 2 1 0

10–1984 09–1985 12 –1.1 –0.71 LN M 11 8 2 4

08–1986 02–1988 19 1.6 1.11 EN S 11 6 1 2

05–1988 05–1989 13 –1.9 –1.29 LN S 12 6 3 1

05–1991 07–1992 15 1.8 1.13 EN S 9 4 2 1

05–1994 03–1995 11 1.3 0.83 EN M 7 3 0 0

09–1995 03–1996 7 –0.7 –0.63 LN W 7 5 3 1

05–1997 05–1998 13 2.5 1.74 EN S 8 3 1 1

07–1998 06–2000 24 –1.6 –1.03 LN S 26 18 8 6

10–2000 02–2001 5 –0.7 –0.58 LN W 4 1 0 0

05–2002 03–2003 11 1.5 1.03 EN S 12 4 2 1

06–2004 02–2005 9 0.9 0.72 EN W 15 9 6 6

08–2006 01–2007 6 1.1 0.83 EN M 7 5 2 0

09–2007 05–2008 9 –1.4 –1.04 LN M 13 6 2 1

Table 8. Statistical aspects of EN and LN events based on ONI (ERSST.v3b).

Event Type Number Duration

Recurrence 

Rate* NTC NH NMH NUSLFH

EN 17 10.1 (4.2/5–19) 31.9 (18.3/3–64) 8.0 (3.5/0–15) 4.4 (2.4/0–9) 1.5 (1.6/0–6) 1.0 (1.4/0–6)

LN 13 15.0 (10.7/5–37) 43.2 (30.3/4–101) 14.1 (10.0/0–31) 8.3 (6.4/0–21) 4.0 (3.3/0–10) 2.7 (2.7/0–9)

*Means from the end of one event to the start of the next event of the same type.
28

the start of a new LN event) averages ≈43 mo, having an sd of ≈30 mo and a range of 4 to 101 mo. 

The last LN event ended in May 2008, so based on the average recurrence rate, one might not 

expect another LN to occur anytime soon. While true, the latest forecast is for ENSO-neutral to 

LN-like conditions to prevail during 2009.25 During a LN event, on average, 14 tropical cyclones 

form in the North Atlantic basin during the event, having an sd of ≈10 and a range of zero to 31; 

about 8 hurricanes form, having an sd of ≈6 and a range of zero to 21; ≈4 major hurricanes form, 

having an sd of ≈3 and a range of zero to 10; and ≈3 hurricanes strike the U.S. coastline, having 

an sd of ≈3 and a range of zero to 9. It is apparent then that while numbers of tropical cyclones, 

hurricanes, major hurricanes, and U.S. land-falling hurricanes tend to be depressed during an EN 

event, the opposite seems true for a LN event, usually having considerably higher frequencies in 

comparison.

Figure 8 displays the yearly number of tropical cyclone formations for the low-latitudinal 

groups 2 + 4 (fig. 8(a)) and high-latitudinal groups 1 + 3 + 5 (fig. 8(b)) (recall groups 1–5 previously 

mentioned in sec. 2.2) in relation to the yearly variation of NENM (fig. 8(c)). The thin, jagged line 

is the yearly mean; the thick, smoothed line is the 10-yma trend line; and the thin, horizontal line 

is the long-term average. While it appears true that most (10 of 15) EN peak years, including 1957, 

1965, 1972, 1977, 1982, 1987, 1991, 1994, 1997, and 2002, associate with reduced tropical cyclone 

formation in the lower latitudinal regions of the North Atlantic basin (using the long-term mean 

as the discriminator), some do not, including 1951, 1963, 1969, 2004, and 2006. Also, there is no 

apparent corresponding increase in the number of high-latitudinal tropical cyclones during most EN 

peak years (only 5 of 10 had increased numbers above the long-term average, including 1957, 1969, 

1972, 2002, and 2004). The trend lines for both the low- and high-latitudinal groups now exceed the 

long-term averages, the low-latitudinal group beginning after about 1990 and the high-latitudinal 

group after about 1998. Since 1995, 12 of 14 years have had numbers of tropical cyclones in the lowlatitudinal groups greater than its long-term mean and 10 of 14 years have had numbers of tropical cyclones in the high-latitudinal groups greater than its long-term mean. The average number of 

tropical cyclones since 1995 measures 6.9 for the low-latitudinal group (sd=2.9 and range of 1 to 12) 

and 7.6 for the high-latitudinal group (sd=4.1 and range of 2 to 19).

2.5 First Differences in 10-yma Values of Tropical Cyclone Frequencies

Previously, it was shown that the first differences in the 10-yma values of the tropical cyclone 

frequencies can be used to estimate the seasonal frequencies for the following season.1 The first difference is simply the difference between the following year’s 10-yma value and the current year’s 

10-yma value (recall that 10-yma values always lag real time by 5 yr, so the last available 10-yma is 

for the year 2003).

Figure 9 displays the first differences (fd) of the 10-yma values for (a) NTC, (b) NH, 

(c) NMH, and (d) NUSLFH. To the right is the frequency distribution for each first difference. 

Clearly, the largest grouping of first difference values closely bounds the innermost values (typically, values between ±0.1 and ±0.2). For example, 26 of 53 fd values (49.1%) of fd (NTC) lie within 

the range ±0.1 and 36 of 53 values (67.9%) lie within the range ±0.2. Because the seasonal value1

for 2009 (i.e., NTC (2009)) is equal to 20(X10-yma(–1)± d) –X(–5) –2∑X(i), where X10-yma(–1) is the 

10-yma value for NTC (2003), which equals 15.3; X(–5) is the value of NTC (1999), which equals 12; 
29

1950 1960 1970 1980 1990 2000

 m= 6.1

sd = 2.9

12

6

(c)

Year

NENM

10

15

20

5

(b)

High-Latitude Formation Groups (1+3+5)

Number

 m= 4.4

sd = 2.8

10

15

5

0

0

0

(a)

Low-Latitude Formation Groups (2+4)

Number

Figure 8. Yearly variation of the (a) low-latitude formation groups (2+4), (b) high-latitude 

formation groups (1+3+5), and (c) NENM for the interval 1950–2008.

and 2∑X(i) is twice the sum of NTC between the years 2000 and 2008, which equals 284, NTC (2009) 

is found to equal 10±20d. Presuming d=±0.1, NTC (2009) is computed to be 10±2, while presuming d=±0.2, NTC (2009) is computed to be 10±4. Because there is a 90.6% probability that d≥ –0.2, 

a lower limit of ≈6 can be established for NTC (2009) (i.e., there is only about a 10% probability that 

NTC (2009) <6). There is a 22.6% probability that d >0.2. Hence, there is about a 1 in 4 or 5 chance 

that NTC (2009) will exceed 14. The average d during the interval 1990–2002 is 0.45 (having sd=0.27 

and range = 0.1 to 0.9). Presuming d = 0.45, NTC (2009) is computed to be 19, well below the record 

number of 28 in 2005, yet equal in number to that seen in 1995, which marked the beginning of the 

current high-activity interval and is the second most prolific number of tropical cyclones in a season.
30

1950 1960 1970 1980 1990 2000

0.5

–0.5

0

(c)

(d)

Year

fd (NUSLFH)

fd (NUSLFH)

0.5

–0.5

0

(a)

(b)

fd (NMH)

0.5

–0.5

0

fd (NH)

0

0.5

1 1950–2003

–1

fd (NTC)

–0.5

fd (NTC) fd (NH) fd (NMH)

30 20 10 0

0.5

0–0.5

Frequency

15 10 20 5 0

0.50

–0.5

15 10 20 5 0

0.50

–0.5

15 10 20 5 0

10.50–0.5

–1

FrequencyFrequencyFrequency

P(±0.1): 26/53 = 49.1%P(±0.2): 36/53 = 67.9%P(>0.2): 12/53 = 22.6%P(<–0.2): 5/53 = 9.4%P(±0.1): 31/53 = 58.5%P(>0.1): 15/53 = 28.3%P(<–0.1): 7/53 = 13.2%P(±0.1): 34/53 = 64.2%P(>0.1): 10/53 = 18.9%P(<–0.1): 9/53 = 17.0%P(±0.1): 41/53 = 77.4%P(>0.1): 5/53 = 9.4%P(<–0.1): 7/53 = 13.2%

Figure 9. Yearly variation of the first differences of the 10-yma values of (a) NTC, (b) NH, (c) NMH, and (d) NUSLFH 

for the interval 1950–2002. Also given is the frequency distribution for (a)–(d).
31

For fd (NH), 31 of 53 fd values (58.5%) of fd (NH) lie within the range ±0.1, with a 28.3% 

probability of d >0.1 and a 13.2% probability of d <–0.1. Because NH (2009) = 10±20d, NH (2009) 

can be estimated to be ≈10±2 (using d=±0.1), inferring about an 87% probability that NH (2009) 

≥8. The average d during the interval 1990–2002 is 0.23 (having sd =0.17 and range of zero to 0.5). 

Presuming d=0.23, NH (2009)=14–15, which would be near the record number of 15 that was seen 

in 2005.

For fd (NMH), 34 of 53 fd values (64.2%) lie within the range ±0.1, with an 18.9% probability of d>0.1 and a 17% probability of d<–0.1. Because NMH (2009)=3±20d, NMH (2009) can be 

estimated to be about 3±2 (using d=±0.1), inferring about an 83% probability that NMH (2009) 

≥1. The average d during the interval 1990–2002 is 0.18 (having sd=0.17 and rangeof –0.1 to 0.4). 

Presuming d=0.18, NMH (2009)=6–7, which also is near the record number of 8 that was seen in 

1950.

For fd (NUSLFH), 41 of 53 fd values (77.4%) lie within the range ±0.1, with a 9.4% probability of d>0.1 and a 13.2% probability of d<–0.1. Because NUSLFH (2009) = 3±20d, NUSLFH 

(2009) can be estimated to be about 3±2 (using d=±0.1), inferring about a 90.6% probability that 

NUSLFH ≤5. The average d during the interval 1990–2002 is 0.06 (having sd=0.18 and rangeof –0.3 

to 0.5). Presuming d =0.06, NUSLFH (2009)=4, which is below the record number of 6 that was 

seen in 1985, 2004, and 2005.

2.6 First Differences in 10-yma Values of Latitudinal and Longitudinal Genesis Locations

Figure 10 shows the fd values for (a) <LAT> and (b) <LONG>. As before, for the first difference of the frequencies of tropical cyclones, fd (LAT) and fd (LONG) tend to be centrally located, 

with fd (LAT) having values that typically lie within ±0.5° about 86.8% of the time (46 of 53 seasons) and with fd (LONG) having values that typically lie within ±1° about 90.6% of the time (48 of 

53 seasons). For latitude and longitude, this implies that the 10-yma values for 2004 very probably 

will remain in the lower right quadrant of figure 3. For latitude, there is a 94.3% probability that the 

10-yma of latitude for 2004 will be southward of 21.9° N. For longitude, there is a 98.1% probability 

that the 10-yma for 2004 will be eastward of 63.9° W. Together, this suggests, perhaps, that a greater 

number of tropical cyclones might originate in the lower tropics and farther from the U.S. coastline 

(group 4).

For <LAT> (2009), its value is computed to be about 15.9±20d, or about 15.9±10° N., using 

d=±0.5°. Since yearly values of <LAT> have never fallen below 16.2° N. (1996) or above 32.2° N. 

(1972), this seems to suggest that <LAT> for 2009 will lie somewhere between 16.2° and 25.9° N. 

Based on the 1950–2008 yearly values, individual tropical cyclones have always originated between 

9° N. (Fran in 1990) and 43° N. (an unnamed storm in 1991).

Similarly, for <LONG> (2009), its value is computed to be about 57.9±20d, or about 57.9°

±2° W., using d=±1°. Since yearly values of <LONG> have never been eastward of 52.2° W. (1990) 

or more westward than 79.4° W. (1956), this seems to suggest that <LONG> for 2009 will lie between 

55.9° and 59.9° W., inferring that the yearly average will lie eastward of the mean longitude (64.5° W.). 

Based on the 1950–2008 yearly values, individual tropical cyclones have always originated between 

18.5° W. (an unnamed storm in 1988) and 97.4° W. (Amelia in 1978).
32

1950 1960 1970 1980 1990 2000

–2

–1.5

–1

–0.5

0

0.5

1

1.5

(b)

(a)

Year

–1

0

–0.5

0.5

1

 fd (<LAT>) fd (<LONG>)

P(±0.5): 46/53 = 86.8%

P(>0.5): 3/53 = 5.7%

P(<–0.5): 4/53 = 7.5%

P(±0.5): 26/53 = 49.1%

P(±1.0): 48/53 = 90.6%

P(>0.5): 13/53 = 24.5%

P(<–0.5): 14/53 = 26.4%

P(>1.0): 1/53 = 1.9%

P(<–1.0): 4/53 = 7.5%

Figure 10. Yearly variation of the first differences of the 10-yma values of (a) <LAT> 

and (b) <LONG> for the interval 1950–2002.

2.7 First Differences in 10-yma Values of Peak Wind Speeds and Pressures

Figure 11 displays the fd values for (a) PWS, (b) <PWS>, (c) LP, and (d) <LP>. As before, the 

distribution of fd values tends to be concentrated centrally. For fd (PWS), 29 of 53 seasons (54.7%) 

have values that lie within ±1 kt and 46 of 53 seasons (86.8%) have values that lie within ±2 kt. For 

fd (<PWS>), 44 of 53 seasons (83%) have values that lie within ±1 kt. For fd (LP), 24 of 53 seasons 

(45.3%) have values that lie within ±1 mb and 40 of 53 seasons (75.5%) have values that lie within 

±2 mb. For fd (<LP>), 48 of 53 seasons (90.6%) have values that lie within ±1 mb.
33

1950 1960 1970 1980 1990 2000

P(±1.0): 24/53 = 45.3%

P(±2.0): 40/53 = 75.5%

P(>1.0): 10/53 = 18.9%

P(<–1.0): 19/53 = 35.8%

P(>2.0): 4/53 = 7.5%P(<–2.0): 9/53 = 17.0%P(±1.0): 48/53 = 90.6%

P(>1.0): 2/53 = 3.8%P(<–1.0): 3/53 = 5.7%

5

–5

50

–5

50

–5

50

–5

0

(a)

(b)

(c)

(d)

Year

fd (PWS) fd (<PWS>) fd (LP) fd (<LP>)

P(±1.0): 29/53 = 54.7%

P(±2.0): 46/53 = 86.8%

P(>1.0) 14/53 = 26.4%

P(<–1.0): 10/53 = 18.9%

P(>2.0): 3/53 = 5.7%P(<–2.0): 4/53 = 7.5%P(±1.0): 44/53 = 83.0%

P(>1.0): 3/53 = 5.7%P(<–1.0): 6/53 = 11.3%

Figure 11. Yearly variation of the first differences of the 10-yma values of (a) PWS, (b) <PWS>, 

(c) LP, and (d) <LP> for the interval 1950–2002.
34

For PWS (2009), its computed value is 165±20d, suggesting a 92.5% probability that PWS 

during 2009 will exceed 125 kt (using d=±2). The average d during the interval 1990–2002 is 1.2 

(sd=1.6 and range of –0.7 to 4.7), meaning that if d=1.2 for 2003, then PWS (2009) would be 189 kt. 

The highest yearly PWS is 165 kt (Camille in 1969 and Allen in 1980) and the lowest yearly PWS is 

75 kt (Gladys in 1968). Therefore, it seems more plausible that PWS (2009) ≤165 kt, probably somewhere in the range of 125 to 165 kt.

For <PWS> (2009), its computed value is 95.7±20d, suggesting an 88.7% probability that 

<PWS> for 2009 will exceed 75.7 kt (using d=±1). The average d during the interval 1990–2002 is 

0.4 (sd=0.6 and range of –0.5 to 1.3), meaning that if d=0.4 for 2003, then <PWS> (2009) would be 

103.7 kt. The highest yearly <PWS> is 100.4 kt in 1950 and the lowest yearly <PWS> is 56.3 kt in 

1997. Therefore, it seems more plausible that <PWS> (2009) ≤100.4 kt, probably, somewhere in the 

range of 75.7 to 100.4 kt.

For LP (2009), its computed value is 891±20d, suggesting a 92.5% probability that LP during 2009 will fall below 931 mb (using d=±2). The average d during the interval 1990–2002 is –1.6 

(sd=1.8 and range of –5.3 to 0.7), meaning that if d=–1.6, then LP (2009) would be 899 mb. The 

lowest yearly LP is 882 mb (Wilma in 2005) and the highest yearly LP is 978 mb (Earl in 1986). 

Therefore, it seems more plausible that LP (2009) ≥899 mb, probably, somewhere in the range of 899 

to 931 mb. Only four tropical cyclones have had LP ≤902 mb. These include Gilbert – 888 mb in 1988 

and Katrina – 902 mb, Rita – 897 mb, and Wilma – 882 mb in 2005.

For <LP> (2009), its computed value is 958.3±20d, suggesting a 96.3% probability that 

<LP> for 2009 will fall below 978.3 mb (using d=±1). The average d during the interval 1990–2002 

is –0.4 (sd=0.6 and range of –1.2 to 0.6), meaning that if d=–0.4, then <LP> (2009) would be 

950.3 mb. The lowest yearly <LP> is 951.4 mb in 1955 and the highest yearly <LP> is 992.1 mb in 

1987. Therefore, it seems more plausible that <LP> (2009) ≥951.4 mb, probably, somewhere in the 

range of 951.4 to 978.3 mb.

2.8 Temperature and Decadal-Length Oscillations

Figure 12 shows the yearly variation of (a) the mean surface-air temperature as measured 

at the Armagh Observatory (Northern Ireland) (<AT>) and (b) the <ONI> based on ERSST.v3b 

for the interval 1950–2008, both measured in degrees Celsius and following the same construction 

used in previous figures. Concerning <AT> (fig. 12(a)), the trend line (i.e., 10-yma values, the thick, 

smoothed line) is relatively flat in the 1950s, having a value of about 9.4–9.5 °C (essentially, the 

mean value, 9.47 °C). Cooling occurs in the 1960s and 1970s, followed by a warming from the 1980s 

through the present. The trend line exceeds the mean beginning in 1991 and measures 10.13 °C in 

2002 and 2003, which is the highest 10-yma value ever seen in the Armagh Observatory surfaceair temperature data (extending back to 1844). Since 1995, 10 of 14 years have had yearly <AT> 

exceeding 10 °C, and since 1990, 13 of 19 years have been warmer than the mean temperature. For 

2008, <AT> fell below 10 °C, measuring 9.78 °C, which is the first time this has happened since 

2001. Monthly values of Armagh surface-air temperatures can be found online at <http://climate.

arm.ac.uk/scan.html>26 and monthly and yearly values can be found online at <http://climate.arm.

ac.uk.calibrated/airtemp/index.html>.27
35

1950 1960 1970 1980 1990 2000

–1.5

–1

–0.5

0.5

1

1.5

0

(b)

Year

mean = 9.47 °C

sd = 0.52

8

8.5

9

10

10.5

11

1950–2008

9.5

(a) <AT> (°C) <ONI> (°C)

Figure 12. Yearly variation of the (a) <AT> and (b) <ONI> for the interval 1950–2008.

Concerning <ONI> (fig. 12(b), its trend line typically was of negative value during the 1950s, 

near zero during the 1960s, of negative value again in the 1970s, and of positive value in the 1980s 

and 1990s. The trend line appears to have turned negative again in 2003. Since 1995, 8 of 14 years 

have had yearly <ONI> positive values, and since 1990, 13 of 19 years have had yearly <ONI> positive values. For 2007 and 2008, <ONI> values are –0.30 and –0.56, respectively. (<ONI>, as used 

here, is simply the average of the monthly ONI values for the year. As noted in the Introduction, 

monthly ONI values can be found online.2)
36

Figure 13 displays the yearly variation of three other possibly important indices: (a) <SOI>, 

(b) <NAO>, and (c) <EA>. The SOI is calculated from the monthly or seasonal fluctuations in the 

air pressure difference between Tahiti (French Polynesia) and Darwin (Australia). Sustained negative 

values of the SOI often indicate the occurrences of EN events, while sustained positive values often 

indicate the occurrences of LN events. The SOI monthly values can be found online at <http://www.

bom.gov.au/climate/glossary/soi.shtml>.28

The NAO is a prominent teleconnection pattern, one that consists of a north-south dipole of 

anomalies, with one center located over Greenland and the other of opposite sign spanning central 

latitudes of the North Atlantic Ocean between 35° N. and 40° N. The positive phase of the NAO 

reflects below-normal heights and pressure across the high latitudes of the North Atlantic Ocean 

and above-normal heights and pressure over the central Atlantic Ocean, the eastern United States 

and Western Europe, while the negative phase reflects an opposite pattern of heights and pressure 

over these regions. Both the positive and negative phases are associated with basin-wide changes in 

the intensity and location of the North Atlantic jet stream and storm track, and in large-scale modulations of the normal patterns of zonal and meridional heat and moisture transport.29 The NAO 

exhibits considerable interseasonal and interannual variability, and prolonged periods (of several 

months length) of both positive and negative phases of the pattern are common.

The EA is another prominent teleconnection pattern over the North Atlantic Ocean. It consists of a north-south dipole of anomaly centers spanning the North Atlantic Ocean from east to 

west. The positive phase of the EA pattern is associated with above-average surface temperatures 

in Europe in all months and below-average temperatures over the southern United States during 

January–May and the north-central United States during July–October. The EA pattern exhibits 

very strong multidecadal variability, with the negative phase prevailing during much of 1950–1976 

and the positive phase occurring during much of 1977–2008.30 Monthly values of the NAO and EA 

indices are available online at <ftp://ftp.cpc.ncep.noaa.gov/wd52dg/data/indices/tele_index.nh>.31

Concerning <SOI> (fig. 13(a)), the trend line generally was of positive value between 1950 

and 1977, turning negative in value in 1978 and remaining so until 2003 when its value became positive. The highest yearly positive value occurred in 1950 (15.38) and the most negative yearly value 

occurred in 1987 (–13.08). The value in 2008 was 10.17. Since 1995, 8 of 14 years have had yearly 

<SOI> negative values, and since 1990, 13 of 19 years have had yearly <SOI> negative values.

Concerning <NAO> (fig. 13(b)), the trend line was of negative value prior to 1974 and generally of positive value since 1974, although it appears highly likely to be on the precipice of turning 

negative once again. The highest yearly positive value occurred in 1989 (0.70) and the most negative 

yearly value occurred in 1968 (–0.94). The value in 2008 was –0.38. Since 1995, 8 of 14 years have had 

yearly <NAO> negative values, and since 1990, 8 of 19 years have had <NAO> negative values.

Concerning <EA> (fig. 13(c)), the trend line was of negative value prior to 1978 and has been 

of positive value since 1978. The highest yearly positive value occurred in 1998 (0.93) and the most 

negative yearly value occurred in 1976 (–1.04). The value in 2008 was 0.37. Since 1995, 13 of 14 years 

have had positive yearly <EA> values, and since 1990, 16 of 19 years have had positive yearly <EA> 

values.
37

1950 1960 1970 1980 1990 2000

–1

–0.5

0

0.5

1

(c)

Year

<EA>

–1

–0.5

0

0.5

1

(b)<NAO>

–15

–10

–5

0

5

10

15 1950–2008

(a)<SOI>

Figure 13. Yearly variation of the (a) <SOI>, (b) <NAO>, and (c) <EA> 

for the interval 1950–2008.
38

2.9 First Differences in 10-yma Values of <AT>, <ONI>, <SOI>, <NAO>, and <EA>

Figure 14 shows the fd values for (a) <AT>, (b) <ONI>, (c) <SOI>, (d) <NAO>, and 

(e) <EA>. For fd (<AT>), 39 of 53 fd values (73.6%) lie within the range ±0.05, with 18.9% probability of d>0.05 and a 7.5% probability of d<–0.05. Because <AT> (2009)=10.48±20d, <AT> 

(2009) can be estimated to be 10.48±1 °C (using d=±0.05), inferring about 92.5% probability that 

<AT> (2009) ≥9.48 °C. The average d during the interval 1990–2002 is 0.05 (sd=0.03 and range of 

zero to 0.09). Presuming d=0.05, <AT> (2009)=11.48 °C, which if true, would be a new record high 

at Armagh (the present record high is 10.59 °C in 2007, which is the highest yearly mean temperature 

at Armagh going back to 1844).

For fd (<ONI>), 32 of 48 fd values (66.7%) lie within the range ±0.05, with an equal 

number of fd values lying both above or below the central range (16.7% each). Because <ONI> 

(2009)=–0.46±20d, <ONI> (2009) can be estimated to be –0.46±1 °C (using d=±0.05), inferring 

about an 83.4% probability of <ONI> (2009) being either ≥ –1.46 °C or ≤0.54 °C. The average d during the interval 1990–2002 is –0.02 (sd=0.05 and range=–0.11 to 0.05). Presuming d=–0.02, <ONI> 

(2009)=–0.86 °C.

For fd (<SOI>), 26 of 53 fd values (49.1%) lie within the range ±0.5, with a 28.3% probability of d >0.5 and a 22.6% probability of d<–0.5. Because <SOI> (2009)=–3.21 ± 20d, <SOI> 

(2009) can be estimated to be –3.21±10 (using d=±0.5), inferring about a 77.4% probability of 

<SOI> (2009) being ≥ –13.21. The average d during the interval 1990–2002 is 0.36 (sd=0.51 and 

range=–0.45 to 1.22). Presuming d=0.36, <SOI> (2009) = 3.99.

For fd (<NAO>), 44 of 48 fd values (91.7%) lie within the range ±0.05, with an 8.3% probability of d >0.05 and 0% probability of d<–0.05. Because <NAO> (2009)=0.37±20d, <NAO> 

(2009) can be estimated to be 0.37±1 (using d=±0.05), inferring about a 100% probability of 

<NAO> (2009) being ≥ –0.63. The average d during the interval 1990–2002 is –0.02 (sd=0.02 and 

range=–0.05 to 0.03). Presuming d=–0.02, <NAO> (2009)=–0.03.

For fd (<EA>), 40 of 48 fd values (83.3%) lie within the range ±0.05, with a 14.6% probability 

of d>0.05 and a 2.1% probability of d<–0.05. Because <EA> (2009)=0.77±20d, <EA> (2009) can 

be estimated to be 0.77±1 (using d=±0.05), inferring about a 97.9% probability of <EA> (2009) 

being ≥ –0.23. The average d during the interval 1990–2002 is 0.03 (sd=0.04 and range=–0.06 to 

0.08). Presuming d=0.03, <EA> (2009)=1.37, which is higher than 0.93 in 1998, the previous high.

2.10 Single- and Bi-Variate Fits

Visual comparison of figures 1, 2, 6, and 7 against figures 12 and 13 and of figures 9–11 against 

figure 14 suggests possibly strong associations to exist between 10-yma values of the tropical cyclone 

parameters and, in particular, Armagh temperature, and perhaps some of the decadal-length oscillation parameters as well. Table 9 gives the results of linear regression analysis comparing 10-yma 

values of the parameters, grouped by the determining parameter (i.e., <AT>, <ONI>, <SOI>, 

<NAO>, and <EA>), arranged in decreasing order of the inferred coefficient of correlation (r), 

and limited to confidence levels (cl) >95% for the common interval 1955–2003. Some 26 correlations 

are identified. Interestingly, 9 of the 10 tropical cyclone parameters associate strongly with Armagh 
39

1950 1960 1970 1980 1990 2000

–0.10

–0.05

0

0.05

0.10

 –0.05

 –0.10

0

0.05

0.10

–1.5

–1.0

–0.5

0

0.5

1.0

1.5

(c)

(d)

(e)

Year

 fd (<EA>) fd (<NAO>) fd (<SOI>) fd (<AT>) fd (<ONI>)

P(±0.05): 44/48 = 91.7%

P(>0.05): 4/48 = 8.3%

P(<–0.05): 0/48 = 0.0%

P(±0.5): 26/53 = 49.1%

P(>0.5): 15/53 = 28.3%

P(<–0.5): 12/53 = 22.6%

–0.15

–0.10

–0.05

0

0.05

0.10

0.15

–0.10

–0.05

0

0.05

0.10

0.15

(b)

(a)

P(±0.05): 39/53 = 73.6%

P(>0.05): 10/53 = 18.9%

P(<–0.05): 4/53 = 7.5%

P(±0.05): 32/48 = 66.7%

P(>0.05): 8/48 = 16.7%

P(<–0.05): 8/48 = 16.7%

P(±0.05): 40/48 = 83.3%

P(>0.05): 7/48 = 14.6%

P(<–0.05): 1/48 = 2.1%

Figure 14. Yearly variation of the first differences of the 10-yma values of (a) <AT>, 

(b) <ONI>, (c) <SOI>, (d) <NAO>, and (e) <EA> for the interval 1950–2002.
40

Table 9. Inferred statistically important linear regressions (cl>95%).

Regression Equation r r×r se cl

NTC = –35.460 + 4.864<AT> 0.880 0.775 0.792 >99.9

NH = –16.127 + 2.348<AT> 0.851 0.725 0.464 >99.9

LP = 1,060.636 – 13.059<AT> –0.785 0.616 3.124 >99.9

NMH = –14.519 + 1.797<AT> 0.693 0.480 0.564 >99.9

<LAT> = 59.192 – 3.877<AT> –0.673 0.452 1.288 >99.9

NUSLFH = –3.973 + 0.583<AT> 0.537 0.288 0.277 >99.9

<LONG> = 96.090 – 3.344<AT> –0.460 0.212 1.918 >99.9

PWS = 63.986 + 6.530<AT> 0.409 0.167 4.358 >99.5

<LP> = 1,020.133 – 4.305<AT> –0.401 0.161 2.966 >99.5

<LONG> = 64.707 – 10.696<ONI> –0.824 0.679 1.247 >99.9

<LAT> = 22.730 – 4.830<ONI> –0.470 0.220 1.537 >99.9

<PWS> = 74.576 – 9.055<ONI> –0.410 0.168 3.406 >99.5

<LONG> = 65.027 + 0.618<SOI> 0.691 0.478 1.581 >99.9

<PWS> = 75.057 + 0.829<SOI> 0.545 0.297 3.129 >99.9

<PWS> = 74.765 – 19.852<NAO> –0.855 0.731 1.938 >99.9

<LP> = 979.389 + 14.173<NAO> 0.703 0.495 2.305 >99.9

PWS = 125.743 – 18.746<NAO> –0.625 0.390 3.773 >99.9

NMH = 2.443 – 2.719<NAO> –0.559 0.312 0.649 >99.9

<LONG> = 64.700 – 7.165<NAO> –0.525 0.276 1.874 >99.9

NTC = 10.100 + 4.093<EA> 0.659 0.435 1.255 >99.9

LP = 938.338 – 11.378<EA> –0.609 0.370 3.989 >99.9

<LONG> = 64.885 – 4.803<EA> –0.588 0.346 1.778 >99.9

NH = 5.897 + 1.512<EA> 0.488 0.238 0.729 >99.9

<PWS> = 74.850 – 6.162<EA> –0.444 0.197 3.348 >99.8

NUSLFH = 1.495 + 0.422<EA> 0.345 0.119 0.308 >98

<LAT> = 22.803 – 2.058<EA> –0.318 0.101 1.648 >95

surface air temperature. Only <PWS> fails to strongly associate with <AT>, although it is strongly 

associated with <NAO>.

Table 10 rearranges the 26 inferred correlations given in table 9 by tropical cyclone parameter 

in descending order of r. For NTC, two correlations are highly statistically important (cl>99.9%), the 

strongest being the one against the 10-yma of <AT>. Its r equals 0.880, inferring that the regression 

can explain about 77.5% of the variance in the 10-yma of NTC. <AT> also provides the strongest 

correlations for NH (r=0.851), NMH (r=0.693), NUSLFH (r=0.537), <LAT> (r=–0.673), and 

LP (r=–0.785). <ONI> provides the strongest correlation for <LONG> (r =–0.824), and <NAO> 

provides the strongest correlations for PWS (r=–0.625), <PWS> (r=–0.855), and <LP> (r=0.703).

Table 11 gives the results of bi-variate analysis for the interval 1955–2003 for the tropical cyclone parameters, using <AT> in combination with each of the other determining parameters (i.e., <ONI>, <SOI>, <NAO>, and <EA>), arranged by tropical cyclone parameter and in 
41

Table 10. Inferred statistically important linear regressions (cl>95%), grouped by tropical 

cyclone parameter in descending order of r.

Regression Equation r r×r se cl

NTC = –35.460 + 4.864<AT> 0.880 0.775 0.792 >99.9

NTC = 10.100 + 4.093<EA> 0.659 0.435 1.255 >99.9

(NTC: m = 10.345, sd = 1.652)

NH = –16.127 + 2.348<AT> 0.851 0.725 0.464 >99.9

NH = 5.897 + 1.512<EA> 0.488 0.238 0.729 >99.9

(NH: m = 5.988, sd = 0.825)

NMH = –14.519 + 1.797<AT> 0.693 0.480 0.564 >99.9

NMH = 2.443 – 2.719<NAO> –0.559 0.312 0.649 >99.9

(NMH: m = 2.404, sd = 0.775)

NUSLFH = –3.973 + 0.583<AT> 0.537 0.288 0.277 >99.9

NUSLFH = 1.495 + 0.422<EA> 0.345 0.119 0.308 >98

(NUSLFH: m = 1.520, sd =0.325)

<LAT> = 59.192 – 3.877<AT> –0.673 0.452 1.288 >99.9

<LAT> = 22.730 – 4.830<ONI> –0.470 0.220 1.537 >99.9

<LAT> = 22.803 – 2.058<EA> –0.318 0.101 1.648 >95

(<LAT>: m = 22.680, sd = 1.723)

<LONG> = 64.707 – 10.696<ONI> –0.824 0.679 1.247 >99.9

<LONG> = 65.027 + 0.618<SOI> 0.691 0.478 1.581 >99.9

<LONG> = 64.885 – 4.803<EA> –0.588 0.346 1.778 >99.9

<LONG> = 64.700 – 7.165<NAO> –0.525 0.276 1.874 >99.9

<LONG> = 96.090 – 3.344<AT> –0.460 0.212 1.918 >99.9

(<LONG>: m = 64.598, sd = 2.172)

PWS = 125.743 – 18.746<NAO> –0.625 0.390 3.773 >99.9

PWS = 63.986 + 6.530<AT> 0.409 0.167 4.358 >99.5

(PWS: m = 125.476, sd = 4.775)

<PWS> = 74.765 – 19.852<NAO> –0.855 0.731 1.938 >99.9

<PWS> = 75.057 + 0.829<SOI> 0.545 0.297 3.129 >99.9

<PWS> = 74.850 – 6.162<EA> –0.444 0.197 3.348 >99.8

<PWS> = 74.576 – 9.055<ONI> –0.410 0.168 3.406 >99.5

(<PWS>: m = 74.482, sd = 3.696)

LP = 1,060.636 – 13.059<AT> –0.785 0.616 3.124 >99.9

LP = 938.338 – 11.378<EA> –0.609 0.370 3.989 >99.9

(LP: m = 937.657, sd = 4.974)

<LP> = 979.389 + 14.173<NAO> 0.703 0.495 2.305 >99.9

<LP> = 1,020.133 – 4.305<AT> –0.401 0.161 2.966 >99.5

(<LP>: m = 979.592, sd = 3.207)
42

Table 11. Statistically important bi-variate correlations, grouped by tropical cyclone 

parameter in descending order of R.

Bi-variate Fit R R×R SE

NTC = –37.133 + 5.049<AT> + 0.098<SOI> 0.904 0.818 0.720

NTC = –39.378 + 5.282<AT> – 1.741<ONI> 0.893 0.797 0.761

NTC = –36.003 + 4.923<AT> – 0.857<NAO> 0.883 0.779 0.793

NTC = –31.797 + 4.471<AT> + 0.640<EA> 0.882 0.779 0.794

(NTC: m = 10.345, sd = 1.652)

NH = –17.432 + 2.490<AT> – 2.003<NAO> 0.933 0.870 0.304

NH = –17.735 + 2.526<AT> + 0.094<SOI> 0.888 0.789 0.387

NH = –19.048 + 2.660<AT> – 1.291<ONI> 0.883 0.779 0.396

NH = –19.357 + 2.695<AT> – 0.568<EA> 0.861 0.742 0.428

(NH: m = 5.988, sd = 0.825)

NMH = –16.620 + 2.025<AT> – 3.231<NAO> 0.953 0.908 0.240

NMH = –16.880 + 2.058<AT> + 0.138<SOI> 0.811 0.658 0.463

NMH = –23.567 + 2.768<AT> – 1.590<EA> 0.798 0.637 0.477

NMH = –18.503 + 2.222<AT> – 1.765<ONI> 0.770 0.593 0.505

(NMH: m = 2.404, sd = 0.775)

NUSLFH = –4.422 + 0.632<AT> – 0.685<NAO> 0.626 0.391 0.259

NUSLFH = –4.310 + 0.624<AT> + 0.066<SOI> 0.569 0.324 0.273

NUSLFH = –4.296 + 0.618<AT> – 0.055<EA> 0.537 0.289 0.280

NUSLFH = –4.345 + 0.623<AT> – 0.163<ONI> 0.537 0.289 0.280

(NUSLFH: m = 1.520, sd = 0.325)

<LAT> = 60.886 – 4.061<AT> + 2.587<NAO> 0.720 0.518 1.222

<LAT> = 69.282 – 4.960<AT> + 1.771<EA> 0.703 0.495 1.251

<LAT> = 54.061 – 3.330<AT> – 2.274<ONI> 0.698 0.488 1.260

<LAT> = 58.204 – 3.768<AT> + 0.058<SOI> 0.684 0.468 1.284

(<LAT>: m = 22.680, sd = 1.723)

<LONG> = 73.446 – 0.929<AT> – 9.998<ONI> 0.796 0.633 1.344

<LONG> = 86.564 – 2.292<AT> + 0.551<SOI> 0.757 0.572 1.451

<LONG> = 91.856 – 2.885<AT> – 6.450<NAO> 0.635 0.403 1.714

<LONG> = 72.111 – 0.771<AT> – 4.206<EA> 0.605 0.366 1.766

(<LONG>: m = 64.598, sd = 2.172)

PWS = 50.420 + 8.001<AT> – 20.771<NAO> 0.772 0.596 3.100

PWS = 49.444 + 8.136<AT> + 0.843<SOI> 0.583 0.340 3.963

PWS = 36.081 + 9.506<AT> – 12.328<ONI> 0.537 0.288 4.116

PWS = 19.223 + 11.331<AT> – 7.524<EA> 0.523 0.274 4.156

(PWS: m = 125.476, sd = 4.775)

<PWS> = 57.976 + 1.783<AT> – 20.321<NAO> 0.849 0.721 1.993

<PWS> = 1.798 + 7.796<AT> – 12.190<EA> 0.646 0.417 2.882

<PWS> = 55.943 + 2.034<AT> + 0.887<SOI> 0.568 0.322 3.108

<PWS> = 159.981 – 9.067<AT> – 11.485<ONI> 0.417 0.174 3.432

(<PWS>: m = 74.482, sd = 3.696)

LP = 1,076.797 – 14.783<AT> + 7.145<ONI> 0.896 0.802 2.260
43

Bi-variate Fit R R×R SE

LP = 1,064.874 – 13.519<AT> + 6.510<NAO> 0.864 0.746 2.562

LP = 1,067.178 – 13.782<AT> – 0.380<SOI> 0.812 0.659 2.967

LP = 1,046.571 – 11.550<AT> – 2.468<EA> 0.806 0.650 3.008

(LP: m = 937.657, sd = 4.974)

<LP> = 1,031.198 – 5.504<AT> + 15.525<NAO> 0.861 0.741 1.669

<LP> = 1,036.661 – 6.068<AT> + 7.324<ONI> 0.781 0.610 2.045

<LP> = 1,031.102 – 5.517<AT> – 0.639<SOI> 0.642 0.412 2.513

<LP> = 1,077.638 – 10.476<AT> + 10.103<EA> 0.615 0.379 2.582

(<LP>: m = 979.592, sd = 3.207)

descending order of the bi-variate coefficient of correlation (R). Slight improvements in the inferred 

fits are seen, as compared to the single-variate linear correlations (tables 9 and 10), except for 

<LONG>. For example, the best bi-variate fit for NTC is the one using both <AT> and <SOI>. It 

has an r=0.904 and se=0.720, as compared to the single-variate fit using <AT> alone, which has 

R=0.880 and SE=0.792. Similarly, the best bi-variate fits for NH and NMH use the combination 

of <AT> and <NAO>, and appear to greatly improve their estimates, as compared to the singlevariate fits using <AT> alone (from 0.851 to 0.933 and from 0.693 to 0.953, respectively). This suggests that the bi-variate fits might provide a means for improved forecasting of the frequencies of 

North Atlantic basin tropical cyclone activity during a season, provided good estimates for <AT>, 

<ONI>, <SOI>, <NAO>, and <EA> can be made. The combination of <AT> and <NAO> also 

provides improved correlation for NUSLFH, <LAT>, PWS, and <LP>; the combination of <AT> 

and <ONI> provides improved correlation for LP; and the single-variate fit using <ONI> alone 

seems to be the best for estimating <LONG>.

Previously, it was shown1 that the current high-activity interval has even stronger correlations 

when limited to just the last several years or so. The analysis is repeated here using a slightly longer 

interval (1990–2003) and using all the parameters (<AT>, <ONI>, <SOI>, <NAO>, and <EA>), 

not just <AT> and <ONI>. Table 12 gives the results of single-variate linear correlation analysis 

arranged like table 10. Plainly, limiting the analysis to just the last several years (i.e., the current highactivity interval) greatly strengthens all of the inferred correlations. Because the linear correlation 

analyses typically resulted in correlations having r>0.9, bi-variate analysis was eschewed.

Using the more limited interval 1990–2003, one finds that the correlation between NTC and 

<AT> is even more highly statistically important, having r=0.977 and se=0.488, than that found for 

the longer interval 1955–2003 (table 10), having r=0.880 and se=0.792, or than that derived using 

the best bi-variate correlation (table 11), having R=0.904 and SE=0.720. Presuming the validity of 

the inferred limited interval correlations for the 2004 10-yma estimated values, one might be able to 

better guess, in particular, the frequencies for the 2009 North Atlantic basin hurricane season, and 

possibly even for the values of the other tropical cyclone parameters (<LAT>, <LONG>, PWS, 

<PWS>, LP, and <LP>) as well.

Table 11. Statistically important bi-variate correlations, grouped by tropical cyclone 

parameter in descending order of R (Continued).
44

Table 12. Results of single-variate linear correlation analysis using the limited time interval 

1990–2003 (n=14), grouped by tropical cyclone parameter in descending order of r.

Regression Equation r r×r se cl

NTC = –72.326 + 8.622<AT> 0.977 0.955 0.488 >99.9

NTC = 15.214 + 1.140<SOI> 0.959 0.920 0.564 >99.9

NTC = 8.283 + 11.263<EA> 0.957 0.916 0.577 >99.9

NTC = 13.936 – 14.772<NAO> –0.933 0.870 0.717 >99.9

NTC = 15.217 – 16.343<ONI> –0.863 0.745 1.005 >99.9

(NTC: m = 12.321, sd = 1.921)

NH = –36.186 + 4.385<AT> 0.985 0.970 0.217 >99.9

NH = 7.709 – 7.725<NAO> –0.967 0.935 0.248 >99.9

NH = 8.296 + 0.564<SOI> 0.941 0.885 0.333 >99.9

NH = 4.869 + 5.564<EA> 0.937 0.878 0.354 >99.9

NH = 8.310 – 8.159<ONI> –0.854 0.729 0.521 >99.9

(NH: m = 6.864, sd = 0.969)

NMH = 3.576 – 6.314<NAO> –0.980 0.960 0.161 >99.9

NMH = –31.290 + 3.481<AT> 0.969 0.939 0.220 >99.9

NMH = 4.039 + 0.454<SOI> 0.939 0.882 0.273 >99.9

NMH = 1.302 + 4.417<EA> 0.922 0.850 0.315 >99.9

NMH = 4.053 – 6.592<ONI> –0.855 0.731 0.424 >99.9

(NMH: m = 2.886, sd = 0.782)

NUSLFH = 0.807 + 2.251<EA> 0.878 0.771 0.209 >99.9

NUSLFH = –14.563 + 1.648<AT> 0.857 0.734 0.218 >99.9

NUSLFH = 2.155 + 0.213<SOI> 0.822 0.676 0.247 >99.9

NUSLFH = 1.907 – 2.678<NAO> –0.777 0.604 0.274 >99.8

NUSLFH = 2.111 – 2.804<ONI> –0.680 0.462 0.319 >99

(NUSLFH: m = 1.614, sd = 0.419)

<LAT> = 21.114 + 0.525<ONI> 0.156 0.024 0.355 <90

<LAT> = 21.161 + 0.423<NAO> 0.151 0.023 0.348 <90

<LAT> = 21.118 + 0.249<EA> 0.119 0.014 0.347 <90

<LAT> = 21.181 – 0.010<SOI> –0.049 0.002 0.380 <90

<LAT> = 20.454 + 0.077<AT> 0.0.49 0.002 0.238 <90

(<LAT>: m = 21.207, sd = 0.341)

<LONG> = 63.311 – 9.248<NAO> –0.941 0.886 0.389 >99.9

<LONG> = 60.001 + 6.411<EA> 0.878 0.771 0.606 >99.9

<LONG> = 63.906 + 0.633<SOI> 0.858 0.736 0.633 >99.9

<LONG> = 64.044 – 9.844<ONI> –0.838 0.702 0.666 >99.9

<LONG> = 19.545 + 4.355<AT> 0.795 0.633 0.815 >99.8

(<LONG>: m = 62.300, sd = 1.192)

PWS = –105.796 + 23.641<AT> 0.939 0.882 2.028 >99.9

PWS = 134.102 + 3.078<SOI> 0.907 0.823 2.404 >99.9

PWS = 115.423 + 30.314<EA> 0.903 0.815 2.456 >99.9

PWS = 130.470 – 38.221<NAO> –0.846 0.716 3.037 >99.9
45

Regression Equation r r×r se cl

PWS = 133.783 – 42.284<ONI> –0.783 0.613 3.554 >99.9

(PWS: m = 126.293, sd = 5.482)

<PWS> = 74.551 – 14.582<NAO> –0.958 0.918 0.534 >99.9

<PWS> = –4.306 + 7.870<AT> 0.927 0.895 0.842 >99.9

<PWS> = 75.468 + 0.990<SOI> 0.865 0.748 1.003 >99.9

<PWS> = 69.462 + 9.747<EA> 0.861 0.741 0.984 >99.9

<PWS> = 75.603 – 14.936<ONI> –0.820 0.672 1.098 >99.9

(<PWS>: m = 72.957, sd = 1.848)

LP = 1,236.908 – 30.974<AT> –0.955 0.912 3.005 >99.9

LP = 922.587 – 4.040<SOI> –0.924 0.854 2.536 >99.9

LP = 947.085 – 39.739<EA> –0.918 0.843 2.905 >99.9

LP = 927.256 + 51.053<NAO> 0.877 0.769 3.585 >99.9

LP = 922.941 + 55.857<ONI> 0.802 0.643 4.393 >99.9

(LP: m = 932.836, sd = 7.064)

<LP> = 977.523 + 13.252<NAO> 0.939 0.882 0.759 >99.9

<LP> = 1,050.179 – 7.253<AT> –0.922 0.850 0.962 >99.9

<LP> = 976.743 – 0.878<SOI> –0.829 0.687 1.389 >99.5

<LP> = 981.969 – 8.361<EA> –0.797 0.635 1.291 >99.5

<LP> = 976.956 + 11.758<ONI> 0.669 0.448 1.328 >99

(<LP>: m = 978.971, sd = 1.713)

For NH, the best linear correlation is based on <AT>, having r=0.985 and se=0.217. For 

NMH, the best linear correlation is based on <NAO>, having r= –0.980 and se = 0.161. For NUSLFH, 

the best linear correlation is based on <EA>, having r=0.878 and se=0.209. For <LONG>, the best 

linear correlation is based on <NAO>, having r=–0.941 and se=0.389. For PWS, the best linear 

correlation is based on <AT>, having r=0.939 and se=2.028. For <PWS>, the best linear correlation is based on <NAO>, having r=–0.958 and se=0.534. For LP, the best linear correlation is 

based on <AT>, having r=–0.955 and se=3.005. For <LP>, the best linear correlation is based on 

<NAO>, having r=0.939 and se=0.759. None of the inferred correlations are statistically important 

for <LAT> during the limited interval 1990–2003.

Table 12. Results of single-variate linear correlation analysis using the limited time 

interval 1990–2003 (n=14), grouped by tropical cyclone parameter in 

descending order of r (Continued).
46

3. SUMMARY

As noted in the previous study,1 two groups provide extended forecasts in the month of December prior to the start of hurricane season, while the National Oceanic and Atmospheric Administration (NOAA) gives its official forecast in the month of May just before the start of hurricane season. 

The two groups giving the early estimates include the Colorado State University (CSU) team, given 

by P.J. Klotzbach and W.M. Gray, and the Tropical Storm Risk (TSR) team in the United Kingdom, 

given by M. Saunders and A. Lea. For the 2009 hurricane season, both teams have given initial 

estimates that call for increased activity exceeding long-term averages for NTC, NH, and NMH. 

In particular, the CSU team predicts that the 2009 hurricane season will see 14 tropical cyclones, 

7 hurricanes, and 3 major hurricanes,32 and the TSR team predicts that the 2009 hurricane season 

will see 10–19 tropical cyclones, 5–11 hurricanes, and 2–5 major hurricanes,33 essentially the ±1s 

spread about the mean for the current high-activity interval 1995–2008. (Note added in proof: In 

April 2009, the CSU team reduced its December 2008 estimates for the 2009 hurricane season, from 

14 to 12 tropical cyclones, from 7 to 6 hurricanes, and from 3 to 2 major hurricanes. Also, the TSR 

team slightly altered its estimates from 10 to 19 to about 11 to 19 tropical cyclones and from 5 to 11 to 

5 to 10 hurricanes, while keeping the same estimate of 2 to 5 major hurricanes.)

For the interval 1950–2008, on average, there have been about 11 tropical cyclones, 6 hurricanes, 2–3 major hurricanes, and 1–2 U.S. land-falling hurricanes. Based on Poisson statistics, the 

central 50% intervals correspond approximately to 8–12 for NTC, 4–7 for NH, 1–3 for NMH, and 

1–2 for NUSLFH using the entire interval 1950–2008, with a strong rightward (or positive) skew 

towards higher numbers. Instead, presuming a normal distribution and limiting oneself to the current high-activity interval 1995–2008, one projects the 90% prediction intervals to be about 7–23 for 

NTC, 3–13 for NH, 1–7 for NMH, and zero to 6 for NUSLFH, inferring only a 5% chance of having 

24 or more tropical cyclones, 14 or more hurricanes, 8 or more major hurricanes, and 7 or more U.S. 

land-falling hurricanes.

On the basis of the behavior of NMH, it can be argued that the overall interval 1950–2008 

can be subdivided into two high-activity intervals (1950–1965 and 1995–2008) separated by one lowactivity interval (1966–1994). During the current high-activity interval, 12 of 14 years have had NTC 

above its long-term mean (10.8), averaging ≈14.9 per year (range 8 to 28); 11 of 14 years have had 

NH above its long-term mean (6.3), averaging ≈8.1 per year (range 3 to 15); 10 of 14 years have had 

NMH above its long-term mean (2.7), averaging ≈3.9 per year (range 1 to 7); and 8 of 14 years have 

had NUSLFH above its long-term mean (1.6), averaging ≈2.1 per year (range zero to 6).

During the interval 1950–2008, there have been 171 NENM, 195 NLNM, and 342 NNM. During the current high-activity interval, there have been 42 NENM, 45 NLNM, and 81 NNM, where 

EN and LN events are determined using the ONI, based on the ERSST.v3b. During the interval 

1950–2008, there have been 17 EN and 13 LN events. Since May 1994, there have been 5 EN and 

4 LN events, including two strong EN events (May 1997–May 1998 and May 2002–March 2003) and 
47

one strong LN event (July 1998–June 2000). Since May 1994, the 5 EN events have averaged ≈10 mo 

in duration (range 6 to 13 mo), while the 4 LN events have averaged ≈11 mo in duration (range 5 to 

24 mo). During the interval 1950–2008, the recurrence rate for EN (from the end of one to the start 

of the next), on average, is ≈32 mo (range 3 to 64 mo) and the recurrence rate for LN is ≈43 mo (range 

4 to 101 mo). The last EN event ended in January 2007 and the last LN event ended in May 2008. 

Presently, NOAA forecasts continuing LN-like to ENSO-neutral conditions to prevail in 2009. If the 

prediction is true, then the frequency of tropical cyclones in the North Atlantic basin should be average to above average in number during the 2009 hurricane season. If, however, another EN should 

suddenly appear, then the frequency of tropical cyclones in the North Atlantic basin should be average to below average in number during the 2009 hurricane season. Of the 17 EN events determined 

by ONI during the interval 1950–2008, all have onsets between April and November, with the month 

of May having the most onsets of EN events. Interestingly, 5 of the 6 onsets for EN events occurring 

in May were associated with strong events, and 6 of 8 strong EN events had onsets in April and/or 

May (8 of 8 had onsets in April–August). On average, strong EN events persist ≈13.6 mo in duration, 

peaking ≈6.8 mo after onset. So, if a strong EN event should happen to appear beginning in mid2009, frequencies of tropical cyclones would be expected to be reduced in numbers, as compared to 

the averages of the current high-activity interval.

During any given season, the state of Florida stands better than a 28% chance of being struck 

somewhere along its coastline. Together, the states of Florida, North Carolina, Louisiana, and Texas 

have experienced about two-thirds of all previous land strikes by hurricanes in the United States 

during the interval 1950–2008. During 2008, three land-falling hurricanes struck the U.S. coastline, 

including Dolly (Texas), Gustav (Louisiana), and Ike (Texas and Louisiana).

By season’s end, the location of the 10-yma values for <LAT> and <LONG> for 2004 is 

expected to remain in the lower-right quadrant of figure 3, below about 22.1° N. and eastward of 

64.9° W. This suggests, perhaps, that greater production may occur from the group 4 area (lower 

North Atlantic-Cape Verdi area), an area that between 1950 and 2008 has accounted for about onethird of all tropical cyclones that became hurricanes and ≈30% of all U.S. land-falling hurricanes. 

Certainly, figure 8(a) suggests that tropical cyclones forming in the lower tropics are on the increase 

and will be a main contributor to this season’s NTC, provided EN is not a factor in the 2009 North 

Atlantic basin hurricane season.

The 10-yma of PWS has been higher than its long-term average (127.3 kt) every year between 

1998 and 2003 (the last available 10-yma year). In 2003, it measured 135 kt, a value equal to the 

previous high in 1954. The 10-yma of <PWS> for 2003 measures 75 kt, a value near its long-term 

average, but well below the peak <PWS> of 83.3 kt in 1954. If the current high-activity interval 

continues, it might be that 10-yma values of PWS and <PWS> will plateau or possibly continue to 

increase to even higher values. 

Similarly, since 1997, the 10-yma of LP has fallen from 935.9 mb to 922.1 mb, well below its 

long-term average of 931.7 mb. During the current high-activity interval, there have been 8 tropical 

cyclones having LP ≤920 mb, the lowest (and record holder) being 882 mb by Wilma in 2005. The 

year 2005 is the only year to have more than a single tropical cyclone having LP ≤920 mb (Katrina, 

Rita, and Wilma). The 10-yma of <LP> in 2003 (977.3 mb), while lower than its long-term average 
48

(978.8 mb), remains higher than was seen in the 1950s (972.4 mb in 1951). Again, presuming the continuation of the current high-activity interval, values of LP and <LP> might possibly bottom out or 

continue to decline to even lower (stronger) values.

First differences of the 10-yma frequencies of tropical cyclones allows for the crude prediction of the next season’s frequencies, provided the year is not a statistical outlier. Of the 53 fd values for NTC, about 50% fall within d=±0.1 and about 68% fall within d=±0.2. For the year 2009, 

presuming it will not be a statistical outlier year, NTC=10±2d, inferring about a 2 out of 3 chance 

that it will measure about 6–14. Because there is better than a 1 in 5 chance that d>0.2, NTC in 

2009 could be higher than 14. The average d during the interval 1990–2002 is 0.45, inferring that 

NTC could be as high as 19, if d for 2003 is 0.45. For the other tropical cyclone parameters, the year 

2009 should see about ≥8 NH, possibly as many as 15 if d for 2003 measures 0.23, the average d for 

1990–2002; ≥1 NMH, possibly as many as 7 if d for 2003 measures 0.18, the average d for 1990–2002; 

≤5 NUSLFH (there is only about a 10% chance of NUSLFH ≥6); 16.2° N. ≤ <LAT> ≤ 25.9° N.; 

55.9° W. ≤ <LONG> ≤ 59.9° W.; 125 kt ≤ PWS ≤ 165 kt; 75.7 kt ≤ <PWS> ≤ 100.4 kt; 899 mb ≤ LP 

≤ 931 mb; and 951.4 mb ≤ <LP> ≤ 978.3 mb.

Because <AT> and some of the decadal-length oscillation parameters bear strong resemblance 

to the variations of the tropical cyclone parameters, close correlation is expected and was, indeed, 

found, especially between the tropical cyclone parameters and <AT>. For example, the decreasing frequencies and weakening strengths of the tropical cyclones during the mid-1960s through the 

mid-1990s associates strongly with a cooling as described using <AT>, while the higher frequencies 

and stronger cyclones of the 1950s and now the mid-1990s through the present strongly associate 

with warmer temperatures. In particular, the 10-yma of <AT> exceeds its long-term average (9.47 

°C) beginning in 1991 and now measures 10.13 °C in 2002 and 2003, the highest 10-yma values 

ever recorded at Armagh Observatory (Northern Ireland) going back more than 150 yr. Since 1995, 

10 of 14 years have had yearly averages of <AT> exceeding 10 °C, and since 1990, 13 of 19 years have 

been warmer than the mean temperature. For 2008, Armagh surface air temperature fell below 10 °C 

(to 9.78 °C), the first such instance since 2001. 

Like the tropical cyclone parameters, first difference values of the 10-yma values of <AT> 

lie close to the central value of zero. For <AT>, 39 of 53 fd values (nearly 75%) lie within the range 

±0.05, with nearly a 1 in 5 chance of being >0.05. <AT> for 2009 is expected to be about 10.48

±1 °C, with better than a 90% probability that it will measure ≥9.48 °C. The average d during the 

interval 1990–2002 is 0.05, inferring <AT> = 11.48 °C, if d for 2003 is 0.05. Any yearly <AT> value 

above 10.59 °C (the highest yearly temperature in 2007) represents a new record high.

For the decadal-length oscillation parameters, values for 2009 are expected to be about 

–0.86 °C for ONI (presuming d=–0.02, the average d for the interval 1990–2002); 3.99 for <SOI> (presuming d=0.36, the average d for the interval 1990–2002); –0.03 for <NAO> (presuming d=–0.02, 

the average d for the interval 1990–2002); and 1.37 for <EA>, which is higher than its record high 

of 0.93 in 1998 (presuming d=0.03, the average d for the interval 1990–2002). For the 2009 parameters, there is >80% probability that ONI will be either ≥ –1.46 °C or ≤ 0.54 °C; >75% probability that 

<SOI>≥ –13.21; essentially a 100% probability that <NAO>≥ –0.63; and nearly 98% probability that 

<EA>≥–0.23.
49

Presuming d=±0.05 °C for <AT>, the 10-yma of <AT> for 2004 equals 10.13±0.05 °C. 

Using this value in the inferred statistically important linear regression best-fits for the limited time 

interval 1990–2003 (table 12) allows for the estimate of the frequencies of tropical cyclones, yielding 

10-yma expected values for 2004 of NTC, NH, NMH, and NUSLFH, respectively, equal to 15±0.4, 

8.2 ± 0.3, 4 ± 0.1, and 2.1 ± 0.1. The 10-yma value of NTC = 15, however, appears too low to be 

statistically meaningful, for it suggests a yearly value of ≈4 for NTC in 2009, which has only occurred 

once in the past 59 hurricane seasons (in 1983) and has a probability of occurrence based on Poisson statistics of only 1.7%; the value of 15.4, on the other hand, suggests NTC=12 in 2009, which is 

much more reasonable. This may indicate that the 10-yma value of <AT> for 2004 will be ≥10.18 °C, 

inferring a yearly <AT> ≥10.48 °C in 2009. The expected value of 8.2 ± 0.3 for the 10-yma of NH for 

2004 suggests a yearly value in 2009 of 10±6 for NH. Presuming the 10-yma of <AT> for 2004 to be 

≥10.18 °C, the 10-yma of NH ≥ 8.2±0.3 in 2004 and the expected yearly value of NH in 2009 would 

be ≥ 10±6. The expected value of 4±0.1 for the 10-yma value of NMH for 2004 suggests a yearly 

value in 2009 of 7±2 for NMH. Again, presuming the 10-yma of <AT> for 2004 to be ≥10.18 °C, the 

10-yma of NMH ≥ 4±0.1 in 2004 and the expected yearly NMH for 2009 ≥ 7±2. The expected value 

of 2.1±0.1 for the 10-yma value of NUSLFH for 2004 suggests a yearly value in 2009 of 1±3 for 

NUSLFH, inferring fewer than 4 U.S. land-falling hurricanes, possibly none. A larger 10-yma value 

for <AT> in 2004 would increase the likelihood of a greater number of U.S. land-falling hurricanes.

In conclusion, although difficult to reduce the uncertainties, it seems that 2009, more probably than not, will have seasonal frequencies of NTC, NH, NMH, and NUSLFH that will equal or 

exceed long-term averages, a conclusion supported by both temperature and decadal-length oscillation patterns. The biggest unknown is whether or not another EN event should make an unexpected 

appearance. Although NOAA’s current forecast is for continued LN-like to ENSO-neutral conditions to prevail in 2009, based on its recurrence rate, another EN event might soon appear, perhaps, 

either later this year or sometime next year. Also, presuming that EN does not recur in 2009, at least 

one tropical cyclone is expected to have PWS≥140±20 kt and LP possibly below 920 mb, especially, 

if yearly <AT> exceeds 10.48 °C in 2009.
50

APPENDIX

Table 13 is a listing of North Atlantic basin tropical cyclones for the interval 1945–2008.

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008.

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1945 715 Unnamed MH 06/20 17.5 85.7 2 100 – FL1

716 Unnamed TS 07/19 25.5 92.4 1 45 –

717 Unnamed TS 08/01 12.1 56.3 4 50 –

718 Unnamed TS 08/17 17.4 55.3 4 60 –

719 Unnamed MH 08/24 19.4 94.0 1 120 966 TX2

720 Unnamed TS 08/29 13.0 82.6 2 50 993

721 Unnamed TS 09/03 20.0 84.0 1 35 –

722 Unnamed TS 09/10 18.3 60.3 2 50 –

723 Unnamed MH 09/12 19.0 56.6 4 120 951 FL3

724 Unnamed H 10/02 15.3 80.3 2 85 982

725 Unnamed H 10/11 15.5 79.5 2 85 982

Summary: NTC = 11, NH = 5, NMH = 3, NUSLFH = 3

PWS = 120, <PWS> = 72.7, LP = 951, <LP> = 974.8

<N. Lat.> = 17.5, <W. Long.> = 75.2

1946 726 Unnamed TS 06/13 27.0 85.5 1 35 –

727 Unnamed H 07/05 29.0 79.0 2 70 –

728 Unnamed TS 08/25 20.5 93.2 1 35 –

729 Unnamed H 09/12 23.8 79.6 2 85 975

730 Unnamed MH 10/05 18.0 87.2 2 115 979 FL1

731 Unnamed TS 10/31 20.0 71.0 3 40 –

Summary: NTC = 6, NH = 3, NMH = 1, NUSLFH = 1

PWS = 115, <PWS> = 63.3, LP = 975, <LP> = 977.0

<N. Lat.> = 23.1, <W. Long.> = 82.6

1947 732 Unnamed TS 07/31 19.5 92.0 1 40 –

733 Unnamed H 08/09 13.7 74.6 2 95 –

734 Unnamed H 08/18 24.0 80.0 1 70 – TX1

735 Unnamed MH 09/04 14.5 20.1 4 140 947 FL4, LA3, MS3, FL2

736 Unnamed TS 09/07 27.9 85.0 1 40 –

737 Unnamed TS 09/20 18.6 78.1 2 50 989

738 Unnamed TS 10/06 22.0 77.0 3 45 –

739 Unnamed H 10/09 15.4 82.0 2 75 973 GA2, SC2, FL1

740 Unnamed MH 10/16 17.4 62.4 2 105 –
51

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

Summary: NTC = 9, NH = 5, NMH = 2, NUSLFH = 3

PWS = 140, <PWS> = 73.3, LP = 947, <LP> = 969.7

<N. Lat.> = 19.2, <W. Long.> = 72.4

1948 741 Unnamed TS 05/22 16.0 75.0 2 45 –

742 Unnamed TS 07/07 26.3 90.6 1 35 –

743 Unnamed MH 08/26 19.5 58.9 4 105 –

744 Unnamed TS 08/31 13.5 53.0 4 50 1,007

745 Unnamed H 09/01 23.8 94.7 1 70 989 LA1

746 Unnamed MH 09/04 14.3 19.7 4 115 –

747 Unnamed MH 09/18 18.2 78.8 2 105 963 FL3, FL2

748 Unnamed MH 10/03 15.3 81.8 2 115 975 FL2

749 Unnamed H 11/08 24.6 63.3 3 70 –

Summary: NTC = 9, NH = 6, NMH = 3, NUSLFH = 3

PWS = 115, <PWS> = 78.9, LP = 963, <LP> = 983.5

<N. Lat.> = 19.1, <W. Long.> = 68.4

1949 750 Unnamed H 08/21 21.3 62.6 3 95 977 NC1

751 Unnamed MH 08/23 18.2 60.0 2 130 954 FL3

752 Unnamed TS 08/30 11.9 55.8 4 45 –

753 Unnamed MH 09/03 18.4 65.0 2 110 –

754 Unnamed TS 09/03 23.7 89.0 1 40 1,008

755 Unnamed TS 09/05 27.3 40.4 5 40 –

756 Unnamed TS 09/13 15.5 33.7 4 50 –

757 Unnamed H 09/20 26.0 92.0 1 85 –

758 Unnamed H 09/21 16.2 62.5 2 70 –

759 Unnamed MH 09/27 13.3 90.1 P/1 115 – TX2

760 Unnamed H 10/12 18.1 78.6 2 90 –

761 Unnamed TS 10/13 21.8 49.2 5 50 –

762 Unnamed TS 11/03 17.8 82.0 2 50 –

Summary: NTC = 13, NH = 7, NMH = 3, NUSLFH = 3

PWS = 130, <PWS> = 74.6, LP = 954, <LP> = 979.7

<N. Lat.> = 19.2, <W. Long.> = 66.2

1950 763 Able MH 08/12 16.5 54.5 4 120 –

764 Baker MH 08/20 16.3 55.0 4 105 979 AL1

765 Charlie MH 08/21 13.1 24.0 4 100 –

766 Dog MH 08/30 15.2 55.3 4 160 –

767 Easy MH 09/01 19.1 84.1 2 110 958 FL3

768 Fox MH 09/08 15.6 40.1 4 120 –

769 George H 09/27 24.4 52.7 5 95 –

770 How TS 10/01 25.8 88.6 1 50 –

771 Item H 10/08 20.8 90.6 1 95 –

772 Jig MH 10/11 24.3 47.2 5 105 –

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
52

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

773 King MH 10/13 16.0 84.2 2 105 955 FL3

774 Unnamed TS 10/17 22.0 42.0 5 60 –

775 Love H 10/18 27.5 89.2 1 80 –

Summary: NTC = 13, NH = 11, NMH = 8, NUSLFH = 3

PWS = 160, <PWS> = 100.4, LP = 955, <LP> = 964.0

<N. Lat.> = 19.7, <W. Long.> = 62.1

1951 776 Able MH 05/16 31.0 75.3 3 100 –

777 Baker TS 08/02 22.0 54.3 5 50 –

778 Charlie MH 08/15 14.3 55.3 4 115 964

779 Dog MH 08/31 13.4 46.5 4 100 –

780 Easy MH 09/02 14.0 37.0 4 140 –

781 Fox MH 09/04 11.8 29.0 4 100 –

782 George TS 09/20 19.8 93.0 1 50 –

783 How H 10/01 26.1 86.8 1 95 –

784 Item H 10/13 16.2 80.2 2 70 –

785 Jig H 10/15 28.1 75.6 3 70 –

Summary: NTC = 10, NH = 8, NMH = 5, NUSLFH = 0

PWS = 140, <PWS> = 89.0, LP = 964, <LP> = 964.0

<N. Lat.> = 19.7, <W. Long.> = 63.3

1952 786 Unnamed TS 02/02 20.2 87.4 1 50 –

787 Able H 08/24 16.4 51.2 4 90 998 SC1

788 Baker MH 08/31 16.7 58.4 4 105 969

789 Charlie MH 09/23 16.8 67.6 3 105 993

790 Dog H 09/25 14.0 51.0 4 75 998

791 Easy H 10/07 15.5 51.0 4 95 968

792 Fox MH 10/21 15.0 80.7 2 130 934

Summary: NTC = 7, NH = 6, NMH = 3, NUSLFH = 1

PWS = 130, <PWS> = 92.9, LP = 934, <LP> = 976.7

<N. Lat.> = 16.4, <W. Long.> = 63.9

1953 793 Alice TS 05/25 14.4 81.8 2 60 997

794 Barbara H 08/11 22.8 73.9 3 95 987 NC1

795 Unnamed TS 08/28 21.7 82.6 1 50 985

796 Carol MH 08/31 10.6 37.7 4 130 929 ME1

797 Dolly MH 09/08 20.3 65.9 3 100 995

798 Edna MH 09/14 17.0 62.4 2 110 –

799 Unnamed TS 09/14 23.1 94.2 1 60 –

800 Florence MH 09/23 16.9 75.8 2 110 968 FL1

801 Gail H 10/02 13.5 37.0 4 70 –

802 Unnamed TS 10/03 20.3 79.0 3 60 –

803 Unnamed TS 10/05 18.7 40.2 4 60 –

804 Hazel TS 10/07 20.5 86.4 1 60 994

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
53

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

805 Unnamed TS 11/23 22.0 56.5 5 45 –

806 Unnamed TS 12/08 20.8 53.1 5 35 –

Summary: NTC = 14, NH = 6, NMH = 4, NUSLFH = 3

PWS = 130, <PWS> = 74.6, LP = 929, <LP> = 979.3

<N. Lat.> = 18.8, <W. Long.> = 66.2

1954 807 Alice H 06/24 22.0 94.0 1 70 –

808 Barbara TS 07/28 28.0 90.5 1 40 –

809 Carol H 08/25 25.1 75.5 3 85 976 NY3, CT3, RI3, NC2

810 Dolly H 08/31 20.9 68.4 3 85 –

811 Edna MH 09/04 19.3 62.8 2 105 – MA3,

812 Florence H 09/11 20.9 94.7 1 65 –

813 Gilda TS 09/24 14.1 76.8 2 60 –

814 Unnamed H 09/29 31.6 48.4 5 85 –

815 Hazel MH 10/05 12.4 59.2 4 120 937 SC4, NC4, MD2

816 Unnamed TS 11/17 23.8 44.5 5 45 –

817 Alice H 12/30 22.0 51.6 5 70 1,007

Summary: NTC = 11, NH = 8, NMH = 2, NUSLFH = 3

PWS = 120, <PWS> = 75.5, LP = 937, <LP> = 973.3

<N. Lat.> = 21.8, <W. Long.> = 69.7

1955 818 Brenda TS 07/31 27.5 88.4 1 60 –

819 Connie MH 08/03 15.7 39.2 4 125 936 NC3, VA1

820 Diane MH 08/09 18.9 54.3 4 105 969 NC1

821 Edith H 08/23 15.3 51.0 4 85 –

822 Unnamed TS 08/23 17.7 80.0 2 40 –

823 Flora H 09/02 19.0 31.1 4 90 967

824 Gladys H 09/04 21.5 94.6 1 80 –

825 Hilda MH 09/11 18.6 62.9 2 110 952

826 Ione MH 09/10 15.4 44.2 4 105 938 NC3

827 Janet MH 09/21 13.2 54.3 4 150 914

828 Unnamed TS 10/10 28.4 42.0 5 55 –

829 Katie MH 10/15 12.1 77.7 2 100 984

Summary: NTC = 12, NH = 9, NMH = 6, NUSLFH = 3

PWS = 150, <PWS> = 92.1, LP = 914, <LP> = 951.4

<N. Lat.> = 18.6, <W. Long.> = 60.0

1956 830 Unnamed TS 06/12 24.0 91.0 1 50 1,004

831 Anna H 07/26 20.8 93.5 1 70 991

833 Betsy MH 08/09 13.5 47.2 4 105 954

833 Carla TS 09/05 21.5 74.9 3 45 996

834 Dora TS 09/10 20.5 91.1 1 60 1,001

835 Ethel TS 09/12 25.4 74.3 3 60 999

836 Flossy H 09/22 22.2 89.8 1 80 980 LA2, FL1

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
54

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

837 Greta MH 11/02 28.1 73.5 3 120 970

Summary: NTC = 8, NH = 4, NMH = 2, NUSLFH = 1

PWS = 120, <PWS> = 73.8, LP = 954, <LP> = 986.9

<N. Lat.> = 22.0, <W. Long.> = 79.4

1957 838 Unnamed TS 06/08 26.2 87.8 1 60 –

839 Audrey MH 06/25 21.6 93.3 1 125 946 TX4, LA4

840 Bertha TS 08/08 27.0 88.9 1 60 998

841 Carrie MH 09/03 13.7 25.9 4 135 945

842 Debbie TS 09/07 23.9 89.8 1 35 –

843 Esther TS 09/17 23.7 92.8 1 45 1,000

844 Frieda H 09/22 27.8 66.5 3 70 992

845 Unnamed TS 10/23 24.7 60.7 3 50 993

Summary: NTC = 8, NH = 3, NMH = 2, NUSLFH = 1

PWS = 135, <PWS> = 72.5, LP = 945, <LP> = 979.0

<N. Lat.> = 23.6, <W. Long.> = 75.7

1958 846 Alma TS 06/14 21.7 95.0 1 45 997

847 Becky TS 08/11 17.0 35.5 4 50 –

848 Cleo MH 08/11 10.8 21.6 4 140 948

849 Daisy MH 08/24 25.2 73.6 3 110 935

850 Ella MH 08/30 14.0 59.6 4 100 1,009

851 Fifi H 09/05 12.2 49.8 4 80 1,000

852 Gerda TS 09/13 15.9 64.2 2 60 1,004

853 Helene MH 09/23 22.5 64.8 3 115 934 NC3

854 Ilsa MH 09/24 17.7 52.1 4 115 998

855 Janice H 10/05 20.9 81.5 1 80 968

Summary: NTC = 10, NH = 7, NMH = 5, NUSLFH = 1

PWS = 140, <PWS> = 89.5, LP = 934, <LP> = 977.0

<N. Lat.> = 17.8, <W. Long.> = 59.8

1959 856 Arlene TS 05/29 25.3 87.7 1 50 1,000

857 Beulah TS 06/16 22.0 95.6 1 60 987

858 Unnamed H 06/18 30.4 77.7 3 70 993

859 Cindy H 07/07 31.5 77.1 3 65 – SC1

860 Debra H 07/23 27.5 93.1 1 75 984 TX1

861 Edith TS 08/18 14.3 57.9 4 50 1,007

862 Flora H 09/10 22.0 46.0 5 65 994

863 Gracie MH 09/22 21.8 74.1 3 120 950 SC3

864 Hannah MH 09/28 26.9 51.2 5 110 959

865 Irene TS 10/07 27.1 88.9 1 50 1,001

866 Judith H 10/17 21.2 85.1 1 70 999

Summary: NTC = 11, NH = 7, NMH = 2, NUSLFH = 3

PWS = 120, <PWS> = 71.4, LP = 950, <LP> = 987.4

<N. Lat.> = 24.5, <W. Long.> = 75.9

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
55

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1960 867 Unnamed TS 06/23 24.7 96.3 1 40 1,002

868 Abby H 07/10 13.8 61.0 2 85 –

869 Brenda TS 07/29 31.5 81.5 3 50 –

870 Cleo H 08/17 24.4 75.5 3 80 –

871 Donna MH 08/30 10.3 26.9 4 140 932 FL4, NC3, NY3, FL2, CT2, 

RI2, MA1, NH1, ME1

872 Ethel MH 09/14 23.9 90.6 1 140 981 MS1

873 Florence TS 09/18 21.2 66.8 3 40 –

Summary: NTC = 7, NH = 4, NMH = 2, NUSLFH = 2

PWS = 140, <PWS> = 82.1, LP = 932, <LP> = 971.7

<N. Lat.> = 21.4, <W. Long.> = 71.2

1961 874 Anna MH 07/20 11.5 60.2 2 100 976

875 Betsy MH 09/02 13.3 41.7 4 120 945

876 Carla MH 09/05 16.3 82.7 2 150 931 TX4

877 Debbie MH 09/06 15.1 24.1 4 105 970

878 Esther MH 09/11 14.4 36.7 4 125 927

879 Unnamed TS 09/14 34.7 77.9 3 35 –

880 Frances MH 09/30 16.1 58.7 4 110 948

881 Gerda TS 10/19 31.5 71.5 3 60 987

882 Hattie MH 10/27 11.6 81.5 2 140 920

883 Jenny H 11/06 28.8 47.0 5 70 974

884 Inga TS 11/05 20.8 94.7 1 60 992

Summary: NTC = 11, NH = 8, NMH = 7, NUSLFH = 1

PWS = 150, <PWS> = 97.7, LP = 920, <LP> = 957.0

<N. Lat.> = 19.5, <W. Long.> = 61.5

1962 885 Alma H 08/27 30.6 79.7 3 85 986

886 Becky TS 08/28 19.5 23.3 4 35 –

887 Celia TS 09/12 16.4 48.7 4 60 995

888 Daisy H 10/02 21.8 63.2 3 95 968

889 Ella MH 10/15 25.0 72.1 3 100 950

Summary: NTC = 5, NH = 3, NMH = 1, NUSLFH = 0

PWS = 100, <PWS> = 75.0, LP = 968, <LP> = 974.8

<N. Lat.> = 22.7, <W. Long.> = 57.4

1963 890 Arlene H 08/02 11.5 46.0 4 90 969

891 Beulah MH 08/21 15.5 52.8 4 105 958

892 Unnamed TS 09/11 34.8 59.7 5 50 992

893 Cindy H 09/16 26.7 93.7 1 70 996 TX1

894 Debra H 09/21 19.9 47.9 4 65 999

895 Edith H 09/24 12.9 56.5 4 85 990

896 Flora MH 09/29 10.0 52.8 4 125 940

897 Ginny H 10/19 30.8 71.8 3 95 958

898 Helena TS 10/25 15.3 59.4 4 45 1,001

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
56

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

Summary: NTC = 9, NH = 7, NMH = 2, NUSLFH = 1

PWS = 125, <PWS> = 81.1, LP = 944, <LP> = 978.1

<N. Lat.> = 19.7, <W. Long.> = 60.1

1964 899 Unnamed TS 06/07 32.5 78.6 3 50 –

900 Unnamed TS 07/31 33.7 57.2 5 45 1,006

901 Abby TS 08/07 28.5 94.4 1 55 1,000

902 Brenda TS 08/08 32.4 64.9 3 45 1,006

903 Cleo MH 08/21 13.7 49.1 4 135 950 FL2

904 Dora MH 09/01 11.7 47.0 4 115 942 FL2

905 Ethel MH 09/04 18.0 37.0 4 100 969

906 Florence TS 09/08 21.4 29.4 5 40 –

907 Glayds MH 09/13 15.4 46.0 4 125 945

908 Hilda MH 09/29 22.0 84.2 1 130 941 LA3

909 Isbell MH 10/13 20.0 85.0 1 110 964 FL2, FL2

910 Unnamed TS 11/06 13.9 81.4 2 35 997

Summary: NTC = 12, NH = 6, NMH = 6, NUSLFH = 4

PWS = 135, <PWS> = 82.1, LP = 941, <LP> = 972.0

<N. Lat.> = 19.8, <W. Long.> = 62.9

1965 911 Unnamed TS 06/14 24.1 91.1 1 45 –

912 Anna H 08/21 32.4 51.8 5 80 –

913 Betsy MH 08/29 19.2 63.4 2 135 941 FL3, LA3

914 Carol H 09/17 12.4 30.7 4 85 974

915 Debbie TS 09/28 26.5 89.7 5 45 1,001

916 Elena H 10/14 22.0 54.1 5 70 977

Summary: NTC = 6, NH = 4, NMH = 1, NUSLFH = 1

PWS = 135, <PWS> = 76.7, LP = 941, <LP> = 973.3

<N. Lat.> = 22.8, <W. Long.> = 63.5

1966 917 Alma MH 06/06 18.1 84.2 1 110 970 FL2

918 Becky H 07/02 35.8 55.3 5 65 985

919 Celia H 07/14 21.3 61.8 3 70 995

920 Dorothy H 07/23 31.8 41.9 5 75 989

921 Ella TS 07/24 16.8 52.2 4 45 1,008

922 Faith MH 08/22 14.3 28.0 4 110 950

923 Greta TS 09/04 19.8 59.0 4 50 1,004

924 Hallie TS 09/21 21.5 95.4 1 45 997

925 Inez MH 09/24 14.8 48.7 4 130 929 FL1

926 Judith TS 09/28 12.2 51.2 4 45 1,007

927 Lois H 11/06 23.9 53.5 5 70 986

Summary: NTC = 11, NH = 7, NMH = 3, NUSLFH = 2

PWS = 130, <PWS> = 74.1, LP = 929, <LP> = 983.6

<N. Lat.> = 20.9, <W. Long.> = 57.4

1967 928 Arlene H 08/30 20.9 44.8 5 75 982

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
57

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

929 Beulah MH 09/07 13.9 60.8 2 140 923 TX3

930 Chloe H 09/08 22.7 38.0 5 95 958

931 Doria H 09/09 27.8 79.2 3 75 973

932 Edith TS 09/28 14.4 55.1 4 50 1,002

933 Fern H 10/02 21.5 93.0 1 75 987

934 Ginger TS 10/06 18.0 18.1 4 45 1,002

935 Heidi H 10/20 21.4 61.5 3 80 981

Summary: NTC = 8, NH = 6, NMH = 1, NUSLFH = 1

PWS = 140, <PWS> = 79.4, LP = 923, <LP> = 976.0

<N. Lat.> = 20.1, <W. Long.> = 56.3

1968 936 Abby H 06/02 21.4 84.8 1 65 965

937 Brenda H 06/21 30.9 76.3 3 65 990

938 Candy TS 06/23 26.4 96.6 1 60 999

939 Dolly H 08/12 35.0 71.3 3 70 985

940 Edna TS 09/15 15.8 34.9 4 55 1,005

941 ST1 SS(H) 09/16 34.8 67.6 3 70 979

942 Frances TS 09/26 33.2 68.2 3 50 1,001

943 Gladys H 10/15 19.4 83.3 1 75 965 FL2, FL1

Summary: NTC = 8, NH = 5, NMH = 0, NUSLFH = 1

PWS = 75, <PWS> = 63.8, LP = 965, <LP> = 986.1

<N. Lat.> = 27.1, <W. Long.> = 72.9

1969 944 Anna TS 07/27 11.2 36.0 4 60 1,002

945 Blanche H 08/11 32.5 71.1 3 75 997

946 Camille MH 08/14 19.4 82.0 1 165 905 LA5, MS5

947 Debbie MH 08/15 14.0 41.5 4 105 951

948 Eve TS 08/25 29.8 76.0 3 50 996

949 Francelia MH 08/30 14.3 72.2 2 100 973

950 Gerda MH 09/08 29.7 79.7 3 110 979 ME1

951 Holly H 09/15 12.7 48.5 4 75 984

952 Inga MH 09/21 16.7 50.2 4 100 964

953 Unnamed H 09/21 34.1 70.5 3 65 985

954 Unnamed TS 09/25 35.0 38.5 5 60 990

955 ST1 SS(TS) 09/29 24.0 85.7 1 50 996

956 Jenny TS 10/02 25.5 82.1 1 40 1,000

957 Kara H 10/09 27.2 73.3 3 90 978

958 Laurie H 10/19 21.5 89.5 1 90 973

959 Unnamed TS 10/29 32.0 44.5 5 60 990

960 Unnamed H 10/30 42.5 57.0 5 65 988

961 Martha H 11/21 10.3 81.0 2 80 979

Summary: NTC = 18, NH = 12, NMH = 5, NUSLFH = 2

PWS = 165, <PWS> = 80.0, LP = 905, <LP> = 979.4

<N. Lat.> = 24.0, <W. Long.> = 65.5

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
58

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1970 962 Alma H 05/20 15.5 82.5 2 70 993

963 Becky TS 07/20 23.3 86.4 1 55 1,003

964 Celia MH 08/01 23.3 85.8 1 110 945 TX3

965 Unnamed TS 08/18 37.0 72.5 3 60 992

966 Dorothy TS 08/19 12.8 50.7 4 60 996

967 Ella MH 09/10 22.0 89.0 1 110 967

968 Felice TS 09/15 26.5 86.5 1 60 997

969 Greta TS 09/26 22.7 76.2 3 45 1,005

970 Unnamed H 10/13 25.9 65.5 3 90 974

971 Unnamed H 10/21 34.8 45.8 5 65 988

Summary: NTC = 10, NH = 5, NMH = 2, NUSLFH = 1

PWS = 110, <PWS> = 72.5, LP = 945, <LP> = 986.0

<N. Lat.> = 24.4, <W. Long.> = 74.1

1971 972 Arlene TS 07/05 36.7 72.9 3 55 1,000

973 Unnamed H 08/05 40.5 58.5 5 75 974

974 Beth H 08/14 34.4 72.3 3 75 977

975 Chloe TS 08/20 14.3 63.5 2 55 1,004

976 Doria TS 08/27 29.2 77.2 3 55 993

977 Edith MH 09/07 12.7 69.1 2 140 943 LA2

978 Fern H 09/08 26.9 92.6 1 80 978 TX1

979 Ginger H 09/10 27.7 66.1 3 95 959 NC1

980 Heidi TS 09/12 29.2 74.0 3 55 996

981 Irene H 09/17 12.5 73.0 2 70 989

982 Janice TS 09/22 12.0 45.8 4 55 1,005

983 Kristy TS 10/20 33.5 52.8 5 45 992

984 Laura TS 11/14 16.6 82.5 2 60 994

Summary: NTC = 13, NH = 6, NMH = 1, NUSLFH = 3

PWS = 140, <PWS> = 70.4, LP = 943, <LP> = 984.9

<N. Lat.> = 25.1, <W. Long.> = 69.3

1972 985 Alpha SS(TS) 05/26 34.0 73.5 3 60 991

986 Agnes H 06/16 20.0 86.2 1 75 977 FL1, NY1, CT1

987 Betty H 08/24 37.2 56.2 5 90 976

988 Carrie TS 08/31 32.5 72.0 3 60 992

989 Dawn H 09/06 27.3 77.9 3 70 997

990 Charlie SS(TS) 09/20 39.5 59.0 5 60 944

991 Delta SS(TS) 11/02 34.7 48.0 5 40 1,001

Summary: NTC = 7, NH = 3, NMH = 0, NUSLFH = 1

PWS = 90, <PWS> = 65.0, LP = 944, <LP> = 982.6

<N. Lat.> = 32.2, <W. Long.> = 67.5

1973 992 Alice H 07/03 27.8 66.0 3 80 986

993 Alfa SS(TS) 07/31 35.0 72.5 3 40 1,005

994 Brenda H 08/18 21.2 86.0 1 80 977

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
59

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

995 Christine TS 08/28 10.5 30.0 4 60 996

996 Delia TS 09/03 24.0 88.0 1 60 986

997 Ellen MH 09/15 14.0 25.7 4 100 962

998 Fran H 10/09 30.7 62.3 3 70 978

999 Gilda TS 10/18 19.5 79.9 2 60 968

Summary: NTC = 8, NH = 4, NMH = 1, NUSLFH = 0

PWS = 100, <PWS> = 68.8, LP = 962, <LP> = 982.3

<N. Lat.> = 22.8, <W. Long.> = 63.8

1974 1000 ST1 SS(TS) 06/25 25.4 86.2 1 55 1,000

1001 ST2 SS(TS) 07/17 35.0 68.8 3 45 1,006

1002 ST3 SS(TS) 08/10 38.0 70.0 3 50 992

1003 Alma TS 08/13 10.1 52.0 4 55 1,007

1004 Becky MH 08/28 32.1 69.0 3 100 977

1005 Carmen MH 08/30 17.0 67.4 2 130 928 LA3

1006 Dolly TS 09/03 30.2 72.0 3 45 1,004

1007 Elaine TS 09/09 32.3 72.1 3 60 1,001

1008 Fifi H 09/16 17.0 77.8 2 95 971

1009 Gertrude H 09/28 10.8 51.8 4 65 999

1010 ST4 SS(TS) 10/06 23.8 77.0 3 45 1,006

Summary: NTC = 11, NH = 4, NMH = 2, NUSLFH = 1

PWS = 130, <PWS> = 67.7, LP = 928, <LP> = 990.1

<N. Lat.> = 24.7, <W. Long.> = 69.5

1975 1011 Amy TS 06/29 34.4 75.8 3 60 981

1012 Blanche H 07/26 32.2 74.6 3 75 980

1013 Caroline MH 08/29 23.1 92.6 1 100 963

1014 Doris H 08/28 33.3 46.3 5 95 965

1015 Eloise MH 09/16 19.0 65.6 2 110 955 FL3, AL1

1016 Faye H 09/19 20.0 39.0 5 90 977

1017 Gladys MH 09/24 13.5 40.4 4 120 939

1018 Hallie TS 10/26 32.5 78.7 3 45 1,002

1019 ST2 SS(TS) 12/09 41.6 42.9 5 60 985

Summary: NTC = 9, NH = 6, NMH = 3, NUSLFH = 1

PWS = 120, <PWS> = 83.9, LP = 939, <LP> = 971.9

<N. Lat.> = 27.7, <W. Long.> = 61.8

1976 1020 ST1 SS(TS) 05/23 26.3 89.0 1 45 994

1021 Anna TS 07/30 29.8 42.0 5 45 999

1022 Belle MH 08/07 25.6 73.2 3 105 957 NY1

1023 Candice H 08/18 33.4 67.5 3 80 964

1024 Dottie TS 08/19 25.0 81.7 1 45 999

1025 Emmy H 08/22 16.2 56.0 4 90 974

1026 Frances MH 08/28 14.7 45.3 4 100 963

1027 ST3 SS(TS) 09/14 31.0 81.2 3* 40 1,011

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
60

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1028 Gloria H 09/27 25.7 58.0 3 90 970

1029 Holly H 10/23 22.5 58.0 3 65 990

Summary: NTC = 10, NH = 6, NMH = 2, NUSLFH = 1

PWS = 105, <PWS> = 70.5, LP = 957, <LP> = 982.1

<N. Lat.> = 25.0, <W. Long.> = 65.2

1977 1030 Anita MH 08/30 26.8 89.8 1 150 926

1031 Babe H 09/03 27.6 88.5 1 65 995 LA1

1032 Clara H 09/08 35.1 71.7 3 65 993

1033 Dorothy H 09/27 30.9 65.8 3 75 980

1034 Evelyn H 10/14 30.9 64.9 3 70 994

1035 Frieda TS 10/17 17.2 83.9 2 50 1005

Summary: NTC = 6, NH = 5, NMH = 1, NUSLFH = 1

PWS = 150, <PWS> = 79.2, LP = 926, <LP> = 982.2

<N. Lat.> = 28.1, <W. Long.> = 77.4

1978 1036 ST1 SS(TS) 01/19 23.5 47.6 5 40 1,002

1037 Amelia TS 07/31 26.4 97.4 1 45 1,005

1038 Bess TS 08/06 23.9 94.0 1 45 1,005

1039 Cora H 08/08 14.0 43.2 4 80 980

1040 Debra TS 08/28 28.7 94.1 1 50 1,000

1041 Ella MH 08/30 27.3 63.1 3 120 956

1042 Flossie H 09/04 15.5 42.9 4 85 976

1043 Greta MH 09/14 12.5 67.5 2 115 947

1044 Hope TS 09/15 32.9 64.8 3 55 987

1045 Irma TS 10/04 35.1 31.5 5 45 1,001

1046 Juliet TS 10/08 18.8 58.7 4 45 1,006

1047 Kendra H 10/29 24.2 73.2 3 70 990

Summary: NTC = 12, NH = 5, NMH = 2, NUSLFH = 0

PWS = 120, <PWS> = 66.3, LP = 947, <LP> = 987.9

<N. Lat.> = 23.6, <W. Long.> = 64.8

1979 1048 Ana TS 06/22 14.2 54.7 4 50 1,005

1049 Bob H 07/10 23.5 93.8 1 65 986 LA1

1050 Claudette TS 07/17 17.8 60.3 2 45 997

1051 David MH 08/26 11.6 42.2 4 150 924 FL2, FL2, GA2, SC2

1052 Elena TS 08/30 26.8 91.8 1 35 1,004

1053 Frederic MH 08/30 11.5 36.0 4 115 943 AL3, MS3

1054 Gloria H 09/06 22.0 33.8 5 85 975

1055 Henri H 09/16 22.1 92.2 1 75 983

1056 ST1 SS(H) 10/24 35.0 64.0 3 65 980

Summary: NTC = 9, NH = 6, NMH = 2, NUSLFH = 3

PWS = 150, <PWS> = 76.1, LP = 924, <LP> = 977.4

<N. Lat.> = 20.5, <W. Long.> = 63.2

1980 1057 Allen MH 08/02 11.0 42.8 4 165 899 TX3

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
61

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1058 Bonnie H 08/14 14.7 37.3 4 85 975

1059 Charley H 08/21 34.0 68.0 3 70 989

1060 Danielle TS 09/05 29.4 93.4 1 50 1,004

1061 Earl H 09/05 17.8 26.7 4 65 985

1062 Frances MH 09/06 12.7 21.8 4 100 958

1063 Georges H 09/07 34.4 67.9 3 70 993

1064 Hermine TS 09/21 15.1 81.6 2 60 993

1065 Ivan H 10/04 35.6 24.6 5 90 970

1066 Jeanne H 11/09 20.8 85.1 1 85 986

1067 Karl H 11/25 36.0 46.0 5 75 985

Summary: NTC = 11, NH = 9, NMH = 2, NUSLFH = 1

PWS = 165, <PWS> = 83.2, LP = 899, <LP> = 976.1

<N. Lat.> = 23.8, <W. Long.> = 54.1

1981 1068 Arlene TS 05/07 19.0 80.6 2 50 999

1069 Bret TS 06/29 36.0 65.0 3 60 996

1070 Cindy TS 08/03 38.7 64.9 3 50 1,002

1071 Dennis H 08/08 11.3 31.3 4 70 995

1072 Emily H 09/01 29.9 69.7 3 80 966

1073 Floyd MH 09/04 19.0 64.0 2 100 975

1074 Gert H 09/08 15.6 60.6 2 90 988

1075 Harvey MH 09/12 19.4 56.3 4 115 946

1076 Irene MH 09/23 12.5 40.8 4 105 959

1077 Jose TS 10/30 27.7 46.6 5 45 998

1078 Katrina H 11/04 18.3 81.4 1 75 980

1079 ST3 SS(TS) 11/12 31.0 74.0 3 60 978

Summary: NTC = 12, NH = 7, NMH = 3, NUSLFH = 0

PWS = 115, <PWS> = 75.0, LP = 946, <LP> = 981.8

<N. Lat.> = 23.2, <W. Long.> = 61.3

1982 1080 Alberto H 06/03 22.8 85.0 1 75 985

1081 ST1 SS(TS) 06/18 28.7 82.8 1 60 984

1082 Beryl TS 08/28 13.9 22.7 4 63 989

1083 Chris TS 09/10 27.3 94.2 1 55 994

1084 Debby MH 09/14 23.5 71.9 3 115 950

1085 Ernesto TS 10/01 26.5 67.8 3 60 997

Summary: NTC = 6, NH = 2, NMH = 1, NUSLFH = 0

PWS = 115, <PWS> = 71.3, LP = 950, <LP> = 983.2

<N. Lat.> = 23.8, <W. Long.> = 70.7

1983 1086 Alicia MH 08/15 27.2 91.0 1 100 963 TX3

1087 Barry H 08/24 27.4 76.3 3 70 986

1088 Chantal H 09/11 31.6 63.3 3 65 994

1089 Dean TS 09/26 28.0 73.0 3 55 999

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
62

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

Summary: NTC = 4, NH = 3, NMH = 1, NUSLFH = 1

PWS = 100, <PWS> = 72.5, LP = 963, <LP> = 985.5

<N. Lat.> = 28.6, <W. Long.> = 75.9

1984 1090 ST1 SS(TS) 08/19 38.0 56.4 5 50 1,000

1091 Arthur TS 08/29 11.2 55.0 4 45 1,004

1092 Bertha TS 08/31 14.9 45.3 4 35 1,007

1093 Cesar TS 08/31 38.9 65.0 3 50 989

1094 Diana MH 09/08 28.5 77.4 3 115 949 NC2

1095 Edouard TS 09/14 20.5 96.2 1 55 998

1096 Fran TS 09/16 14.8 24.8 4 55 994

1097 Gustav TS 09/18 32.1 64.7 3 45 1,006

1098 Hortense H 09/23 29.2 59.1 5 65 993

1099 Isidore TS 09/26 24.7 77.0 3 50 999

1100 Josephine H 10/08 24.1 71.4 3 90 965

1101 Klaus H 11/06 17.0 66.7 2 80 971

1102 Lili H 12/12 34.5 60.5 3 70 980

Summary: NTC = 13, NH = 5, NMH = 1, NUSLFH = 1

PWS = 115, <PWS> = 61.9, LP = 949, <LP> = 988.8

<N. Lat.> = 25.3, <W. Long.> = 63.0

1985 1103 Ana TS 07/16 31.3 66.6 3 60 996

1104 Bob H 07/22 26.2 83.8 1 65 1,002 SC1

1105 Claudette H 08/11 34.0 74.0 3 75 980

1106 Danny H 08/14 23.7 87.8 1 80 988 LA1

1107 Elena MH 08/28 22.6 80.0 1* 110 953 AL3, MS3, FL3

1108 Fabian TS 09/16 26.0 66.5 3 55 994

1109 Gloria MH 09/17 14.6 28.3 4 125 920 NC3, NY3, CT2, NH2, ME1

1110 Henri TS 09/23 35.3 74.3 3 50 996

1111 Isabel TS 10/07 18.5 70.5 2 60 997

1112 Juan H 10/26 23.8 92.5 1 75 971 LA1

1113 Kate MH 11/15 21.1 63.8 3 105 954 FL2, GA1

Summary: NTC = 11, NH = 7, NMH = 3, NUSLFH = 6

PWS = 125, <PWS> = 78.2, LP = 920, <LP> = 977.4

<N. Lat.> = 25.2, <W. Long.> = 71.6

1986 1114 Andrew TS 06/06 29.7 77.5 3 45 999

1115 Bonnie H 06/24 26.6 89.5 1 75 992 TX1

1116 Charley H 08/15 32.2 78.5 3 70 980 NC1

1117 Danielle TS 09/07 11.2 55.8 4 50 1,000

1118 Earl H 09/11 22.4 51.6 5 90 979

1119 Frances H 11/19 23.9 62.9 3 75 1,000

Summary: NTC = 6, NH = 4, NMH = 0, NUSLFH = 2

PWS = 90, <PWS> = 67.5, LP = 979, <LP> = 991.7

<N. Lat.> = 24.3, <W. Long.> = 69.3

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
63

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1987 1120 Unnamed TS 08/09 27.3 94.0 1 40 1,007

1121 Arlene H 08/11 29.4 74.4 3 65 987

1122 Bret TS 08/18 15.1 26.0 4 45 1,000

1123 Cindy TS 09/07 24.6 39.3 5 45 1,000

1124 Dennis TS 09/10 10.8 25.0 4 45 1,000

1125 Emily MH 09/20 11.4 56.4 4 110 958

1126 Floyd H 10/10 16.0 82.2 2 65 993 FL1

Summary: NTC = 7, NH = 3, NMH = 1, NUSLFH = 1

PWS = 110, <PWS> = 59.3, LP = 958, <LP> = 992.1

<N. Lat.> = 19.2, <W. Long.> = 56.8

1988 1127 Alberto TS 08/07 41.5 69.0 3* 35 1,002

1128 Beryl TS 08/08 29.7 89.4 1 45 1,001

1129 Chris TS 08/28 28.2 80.0 3* 45 1,005

1130 Debby H 09/02 20.7 95.2 1 65 987

1131 Ernesto TS 09/03 35.2 53.1 5 55 994

1132 Unnamed TS 09/07 13.8 18.5 4 50 994

1133 Florence H 09/07 22.7 90.2 1 70 983 LA1

1134 Gilbert MH 09/09 14.5 60.1 2 160 888

1135 Helene MH 09/20 13.2 33.8 4 125 938

1136 Isaac TS 09/30 11.4 56.0 4 40 1,005

1137 Joan MH 10/11 10.1 45.0 4 125 932

1138 Keith TS(H) 11/20 17.8 84.5 2 65 945

Summary: NTC = 12, NH = 6, NMH = 3, NUSLFH = 1

PWS = 160, <PWS> = 73.3, LP = 888, <LP> = 972.8

<N. Lat.> = 21.6, <W. Long.> = 64.6

1989 1139 Allison TS 06/26 27.8 95.8 1 45 999

1140 Barry TS 07/11 17.7 48.2 4 45 1,005

1141 Chantal H 07/31 25.4 91.0 1 70 984 TX1

1142 Dean H 08/01 15.8 49.3 4 90 968

1143 Erin H 08/19 18.5 32.7 4 90 968

1144 Felix H 08/26 17.2 22.9 4 75 979

1145 Gabrielle MH 08/31 11.3 24.8 4 125 937

1146 Hugo MH 09/11 12.5 29.2 4 140 918 SC4, NC1

1147 Iris TS 09/18 11.9 53.2 4 60 1,001

1148 Jerry H 10/13 20.4 93.0 1 75 983 TX1

1149 Karen TS 11/30 20.8 84.2 1 50 1,000

Summary: NTC = 11, NH = 7, NMH = 2, NUSLFH = 3

PWS = 135, <PWS> = 78.6, LP = 923, <LP> = 976.5

<N. Lat.> = 18.1, <W. Long.> = 56.8

1990 1150 Arthur TS 07/24 10.5 56.8 4 60 995

1151 Bertha H 07/28 28.6 75.8 3 70 973

1152 Cesar TS 08/02 15.4 32.3 4 45 1,000

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
64

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1153 Diana H 08/05 16.6 83.6 2 85 980

1154 Edouard TS 08/03 39.2 23.3 5 40 1,003

1155 Fran TS 08/13 9.0 53.6 4 35 1,008

1156 Gustav MH 08/25 13.3 49.0 4 105 956

1157 Hortense TS 08/26 14.4 40.0 4 55 993

1158 Isidore H 09/05 10.4 33.8 4 80 979

1159 Josephine H 09/24 19.4 34.4 4 75 980

1160 Klaus H 10/03 16.2 59.6 4 70 985

1161 Lili H 10/06 36.0 44.0 5 65 987

1162 Marco TS 10/10 24.1 82.0 1 55 989

1163 Nana H 10/16 22.1 62.1 3 75 989

Summary: NTC = 14, NH = 8, NMH = 1, NUSLFH = 0

PWS = 105, <PWS> = 65.4, LP = 956, <LP> = 986.9

<N. Lat.> = 19.7, <W. Long.> = 52.2

1991 1164 Ana TS 07/04 36.2 70.7 3 45 1,000

1165 Bob MH 08/16 26.4 75.8 3 100 950 NY2, CT2, RI2, MA2

1166 Claudette MH 09/05 26.2 56.0 5 115 946

1167 Danny TS 09/08 10.3 35.0 4 45 998

1168 Erika TS 09/09 29.3 53.1 5 50 997

1169 Fabian TS 10/15 20.3 84.1 1 40 1,002

1170 Grace H 10/26 27.2 65.5 3 85 980

1171 Unnamed H 10/29 43.0 57.5 5 65 972

Summary: NTC = 8, NH = 4, NMH = 2, NUSLFH = 1

PWS = 115, <PWS> = 68.1, LP = 946, <LP> = 980.6

<N. Lat.> = 27.4, <W. Long.> = 62.2

1992 1172 ST1 SS(TS) 04/22 24.9 61.5 3 45 1,002

1173 Andrew MH 08/17 12.3 42.0 4 150 922 FL5, FL4, LA3

1174 Bonnie H 09/18 33.7 58.0 5 95 965

1175 Charley H 09/22 31.6 34.0 5 95 965

1176 Danielle TS 09/22 32.8 74.2 3 55 1,001

1177 Earl TS 09/29 29.7 79.3 3 55 990

1178 Frances H 10/22 26.6 61.2 3 75 976

Summary: NTC = 7, NH = 4, NMH = 1, NUSLFH = 1

PWS = 150, <PWS> = 81.4, LP = 922, <LP> = 974.4

<N. Lat.> = 27.4, <W. Long.> = 58.6

1993 1179 Arlene TS 06/19 25.9 95.9 1 35 1,000

1180 Bret TS 08/05 10.4 43.4 4 50 1,002

1181 Cindy TS 08/14 14.5 60.9 2 40 1,007

1182 Dennis TS 08/24 15.4 34.0 4 45 1,000

1183 Emily MH 08/25 28.0 60.4 3 100 960 NC3

1184 Floyd H 09/07 26.2 68.2 3 70 966

1185 Gert H 09/15 11.3 83.0 2 85 970

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
65

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1186 Harvey H 09/20 31.5 59.0 5 65 990

Summary: NTC = 8, NH = 4, NMH = 1, NUSLFH = 1

PWS = 100, <PWS> = 61.3, LP = 960, <LP> = 986.9

<N. Lat.> = 20.4, <W. Long.> = 63.1

1994 1187 Alberto TS 07/02 23.7 87.1 1 55 993

1188 Beryl TS 08/15 29.7 85.6 1 50 1,000

1189 Chris H 08/17 11.7 41.2 4 70 979

1190 Debby TS 09/10 13.7 60.2 2 60 1,006

1191 Ernesto TS 09/22 11.8 30.3 4 50 997

1192 Florence H 11/02 23.2 47.7 5 95 972

1193 Gordon H 11/10 14.6 82.7 2 75 980

Summary: NTC = 7, NH = 3, NMH = 0, NUSLFH = 0

PWS = 95, <PWS> = 65.0, LP = 972, <LP> = 989.6

<N. Lat.> = 18.3, <W. Long.> = 62.1

1995 1194 Allison H 06/03 19.3 85.7 2 65 982

1195 Barry TS 07/07 31.6 71.0 3 60 989

1196 Chantal TS 07/14 21.1 64.4 3 60 991

1197 Dean TS 07/30 28.6 94.0 1 40 999

1198 Erin H 07/31 22.3 73.2 3 80 974 FL1, FL2

1199 Felix MH 08/08 15.5 36.4 4 120 929

1200 Gabrielle TS 08/10 23.5 96.5 1 60 990

1201 Humberto H 08/22 13.7 34.3 4 95 968

1202 Iris H 08/22 13.3 50.6 4 95 957

1203 Jerry TS 08/23 26.4 79.7 2 35 1,002

1204 Karen TS 08/28 16.6 41.5 4 45 1,000

1205 Luis MH 08/29 11.6 29.0 4 120 935

1206 Marilyn MH 09/13 11.8 52.7 4 100 950

1207 Noel H 09/27 12.1 40.6 4 65 987

1208 Opal MH 09/30 21.1 88.5 1 130 919 FL3, AL1

1209 Pablo TS 10/05 10.2 37.5 4 50 994

1210 Roxanne MH 10/09 16.5 83.1 2 100 958

1211 Sebastien TS 10/21 16.0 55.1 4 55 1,001

1212 Tanya H 10/27 26.2 57.9 5 75 970

Summary: NTC = 19, NH = 11, NMH = 5, NUSLFH = 2

PWS = 130, <PWS> = 76.3, LP = 919, <LP> = 973.4

<N. Lat.> = 18.8, <W. Long.> = 61.7

1996 1213 Arthur TS 06/19 31.5 78.7 3 45 992

1214 Bertha MH 07/05 11.0 39.0 4 100 960 NC2

1215 Cesar H 07/25 12.1 68.1 2 70 990

1216 Dolly H 08/19 18.2 83.0 2 70 989

1217 Edouard MH 08/22 13.2 31.6 4 125 933

1218 Fran MH 08/27 14.6 44.9 4 105 946 NC3

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
66

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1219 Gustav TS 08/28 11.0 33.6 4 40 1,005

1220 Hortense MH 09/07 15.4 58.3 4 120 935

1221 Isidore MH 09/25 10.3 28.5 4 100 960

1222 Josephine TS 10/06 25.1 91.8 1 60 970

1223 Kyle TS 10/11 16.9 87.1 2 45 1,001

1224 Lili MH 10/16 17.5 83.8 2 100 960

1225 Marco H 11/19 13.8 80.9 2 65 983

Summary: NTC = 13, NH = 9, NMH = 6, NUSLFH = 2

PWS = 125, <PWS> = 80.4, LP = 933, <LP> = 971.1

<N. Lat.> = 16.2, <W. Long.> = 62.3

1997 1226 ST SS(TS) 06/01 33.2 75.3 3 45 1,003

1227 Ana TS 07/01 31.8 75.4 3 40 1,000

1228 Bill H 07/11 31.8 68.9 3 65 987

1229 Claudette TS 07/13 31.9 73.0 3 40 1,003

1230 Danny H 07/17 28.3 91.4 1 70 984 LA1, AL1

1231 Erika MH 09/03 12.3 47.1 4 110 946

1232 Fabian TS 10/05 26.3 63.1 3 40 1,004

1233 Grace TS 10/15 20.3 69.6 3 40 999

Summary: NTC = 8, NH = 3, NMH = 1, NUSLFH = 1

PWS = 110, <PWS> = 56.3, LP = 946, <LP> = 990.8

<N. Lat.> = 27.0, <W. Long.> = 70.5

1998 1234 Alex TS 07/29 13.3 36.8 4 45 1,002

1235 Bonnie MH 08/20 17.3 57.3 4 100 954 NC2

1236 Charley TS 08/21 26.0 94.5 1 60 1,001

1237 Danielle H 08/24 14.2 37.9 5 90 960

1238 Earl H 08/31 22.4 93.8 1 85 964 FL1

1239 Frances TS 09/09 24.2 95.5 1 55 990

1240 Georges MH 09/16 10.6 31.3 4 135 937 FL2, MS2

1241 Hermine TS 09/19 27.5 91.3 1 40 999

1242 Ivan H 09/20 16.0 32.6 5 80 975

1243 Jeanne H 09/21 11.0 19.4 4 90 969

1244 Karl H 09/24 33.2 60.7 3 90 970

1245 Lisa H 10/05 14.2 47.1 4 65 995

1246 Mitch MH 10/22 11.6 77.9 2 155 905

1247 Nicole H 11/24 27.9 29.1 5 75 979

Summary: NTC = 14, NH = 10, NMH = 3, NUSLFH = 3

PWS = 155, <PWS> = 83.2, LP = 905, <LP> = 971.4

<N. Lat.> = 19.2, <W. Long.> = 57.5

1999 1248 Arlene TS 06/12 28.3 57.5 5 50 1,006

1249 Bret MH 08/19 19.8 94.7 1 125 944 TX3

1250 Cindy MH 08/20 13.6 26.6 4 120 942

1251 Dennis H 08/24 22.4 70.0 3 90 962

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
67

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1252 Emily TS 08/24 11.5 53.8 4 45 1,005

1253 Floyd MH 09/08 15.3 48.2 4 135 921 NC2

1254 Gert MH 09/12 14.2 31.9 4 130 930

1255 Harvey TS 09/20 26.3 87.4 1 50 995

1256 Irene H 10/13 18.5 83.4 2 95 960 FL1

1257 Jose H 10/18 10.9 52.8 4 85 979

1258 Katrina TS 10/29 13.2 82.9 2 35 999

1259 Lenny MH 11/14 16.4 79.9 2 135 933

Summary: NTC = 12, NH = 8, NMH = 5, NUSLFH = 3

PWS = 135, <PWS> = 91.3, LP = 921, <LP> = 964.7

<N. Lat.> = 17.5, <W. Long.> = 64.1

2000 1260 Alberto MH 08/04 12.0 22.3 4 110 950

1261 Beryl TS 08/14 23.1 94.6 1 45 1,007

1262 Chris TS 08/18 16.2 55.4 5 35 1,009

1263 Debby H 08/20 13.3 46.8 4 75 993

1264 Ernesto TS 09/02 16.2 49.5 4 35 1,008

1265 Florence H 09/11 30.4 72.2 3 70 985

1266 Gordon H 09/16 22.5 86.7 1 70 981

1267 Helene TS 09/21 24.9 86.6 1 60 986

1268 Isaac MH 09/22 12.3 25.9 4 120 943

1269 Joyce H 09/26 11.5 31.9 4 80 975

1270 Keith MH 09/29 17.4 84.8 2 120 941

1271 Leslie TS 10/05 29.9 77.3 3 60 973

1272 Michael H 10/16 29.9 71.8 3 85 965

1273 Nadine TS 10/20 30.4 57.2 5 50 999

1274 ST SS(TS) 10/25 22.5 70.0 3 55 978

Summary: NTC = 15, NH = 8, NMH = 3, NUSLFH = 0

PWS = 120, <PWS> = 71.3, LP = 941, <LP> = 979.5

<N. Lat.> = 20.8, <W. Long.> = 62.2

2001 1275 Allison TS 06/05 27.5 95.0 1 50 1,002

1276 Barry TS 08/02 26.2 84.9 1 60 991

1277 Chantal TS 08/17 13.1 60.6 2 60 997

1278 Dean TS 08/22 17.9 64.3 2 60 994

1279 Erin MH 09/02 13.2 37.5 4 105 968

1280 Felix MH 09/11 18.6 47.7 4 100 962

1281 Gabrielle H 09/13 25.3 84.9 1 70 975

1282 Humberto H 09/22 27.9 66.3 3 90 970

1283 Iris MH 10/05 14.8 64.5 2 125 948

1284 Jerry TS 10/07 11.0 53.8 4 45 1,004

1285 Karen H 10/11 29.8 62.5 3 70 982

1286 Lorenzo TS 10/30 28.5 44.6 5 35 1,007

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
68

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1287 Michelle MH 11/01 15.8 83.1 2 120 934

1288 Noel H 11/04 33.9 50.4 5 65 986

1289 Olga H 11/24 29.3 50.3 5 80 973

Summary: NTC = 15, NH = 9, NMH = 4, NUSLFH = 0

PWS = 125, <PWS> = 75.6, LP = 934, <LP> = 979.5

<N. Lat.> = 22.2, <W. Long.> = 63.4

2002 1290 Arthur TS 07/15 35.5 73.3 3 50 992

1291 Bertha TS 08/05 29.3 89.2 1 35 1,008

1292 Cristobal TS 08/06 30.4 76.4 3 45 999

1293 Dolly TS 08/29 9.7 32.2 4 50 997

1294 Edouard TS 09/02 30.1 79.7 3 55 1,002

1295 Fay TS 09/06 27.8 93.9 1 50 998

1296 Gustav H 09/08 30.2 71.1 3 85 960

1297 Hanna TS 09/12 26.7 86.4 1 50 1,001

1298 Isidore MH 09/18 17.1 78.1 2 110 934

1299 Josephine TS 09/18 34.7 52.7 5 50 1,004

1300 Kyle H 09/21 30.4 51.6 5 75 980

1301 Lili MH 09/23 12.1 54.6 4 125 940 LA1

Summary: NTC = 12, NH = 4, NMH = 2, NUSLFH = 1

PWS = 125, <PWS> = 65.0, LP = 934, <LP> = 984.6

<N. Lat.> = 26.2, <W. Long.> = 69.9

2003 1302 Ana TS 04/19 33.8 67.6 3 50 994

1303 Bill TS 06/29 23.4 90.5 1 50 997

1304 Claudette H 07/07 13.2 59.8 4 75 982 TX1

1305 Danny H 07/17 32.5 55.2 5 65 1,001

1306 Erika H 08/14 26.4 83.3 1 60 988

1307 Fabian MH 08/28 15.0 36.2 4 125 939

1308 Grace TS 08/30 24.9 93.3 1 35 1,007

1309 Henri TS 09/05 27.7 85.1 1 50 997

1310 Isabel MH 09/06 13.9 32.7 4 145 915 NC2, VA1

1311 Juan H 09/25 28.4 62.0 3 90 969

1312 Kate MH 09/27 21.0 44.2 5 110 952

1313 Larry TS 09/30 21.2 92.5 1 55 993

1314 Mindy TS 10/10 19.1 68.8 2 40 1,002

1315 Nicholas TS 10/14 10.9 41.9 4 60 990

1316 Odette TS 12/04 13.3 75.7 2 55 993

1317 Peter TS 12/07 27.5 34.5 5 60 990

Summary: NTC = 16, NH = 7, NMH = 3, NUSLFH = 2

PWS = 145, <PWS> = 70.3, LP = 915, <LP> = 981.8

<N. Lat.> = 22.0, <W. Long.> = 64.0

2004 1318 Alex MH 08/01 31.6 79.2 3 105 957 NC1

1319 Bonnie TS 08/09 22.5 87.6 1 55 1,001

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
69

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1320 Charley MH 08/10 12.9 65.3 2 125 947 FL4, FL1, FL1, SC1, NC1

1321 Danielle H 08/14 12.6 24.2 4 95 964

1322 Earl TS 08/14 10.5 53.5 4 45 1,009

1323 Frances MH 08/25 11.5 39.8 4 125 937 FL2, FL1

1324 Gaston H 08/28 31.3 78.2 3 65 986 SC1

1325 Hermine TS 08/29 31.1 69.8 3 50 1,002

1326 Ivan MH 09/03 9.7 30.3 4 145 910 AL3, FL3

1327 Jeanne MH 09/14 16.4 62.6 2 105 951 FL3, FL1, FL1

1328 Karl MH 09/16 11.2 32.1 4 125 943

1329 Lisa H 09/20 13.5 35.4 5 65 990

1330 Matthew TS 10/08 24.1 94.2 1 40 997

1331 Nichole SS(TS) 10/10 30.0 65.2 3 45 986

1332 Otto TS 11/26 27.3 41.0 5 45 995

Summary: NTC = 15, NH = 9, NMH = 5, NUSLFH = 6

PWS = 145, <PWS> = 82.3, LP = 912, <LP> = 971.7

<N. Lat.> = 19.7, <W. Long.> = 57.4

2005 1333 Arlene TS 06/09 18.2 83.9 2 60 990

1334 Bret TS 06/29 20.0 95.8 1 35 1,005

1335 Cindy H 07/05 25.1 90.2 1 65 992 LA1

1336 Dennis MH 07/05 13.0 65.9 2 130 930 FL3, AL1

1337 Emily MH 07/12 11.0 46.8 4 140 929

1338 Franklin TS 07/22 25.7 75.9 3 60 997

1339 Gert TS 07/24 20.8 95.0 1 40 1,005

1340 Harvey TS 08/03 29.5 68.6 3 55 994

1341 Irene H 08/07 20.2 45.0 5 90 970

1342 Jose TS 08/22 19.6 95.0 1 45 1,001

1343 Katrina MH 08/24 24.5 76.5 3 150 902 FL1, FL1, LA3, MS3, AL1

1344 Lee TS 08/31 29.0 50.4 5 35 1,006

1345 Maria MH 09/02 21.1 49.4 5 100 962

1346 Nate H 09/06 28.4 66.6 3 80 979

1347 Ophelia H 09/07 27.9 78.8 3 75 976 NC1

1348 Philippe H 09/17 13.5 54.9 4 70 985

1349 Rita MH 09/18 22.2 72.3 3 155 897 FL1, LA3, TX2

1350 Stan H 10/02 19.5 87.2 2 70 977

1351 ST SS(TS) 10/04 35.9 28.5 5 45 997

1352 Tammy TS 10/05 27.3 79.7 3 45 1,001

1353 Vince H 10/08 32.9 20.6 5 65 988

1354 Wilma MH 10/17 16.9 79.6 2 160 882 FL3, FL2

1355 Alpha TS 10/22 16.5 68.5 2 45 998

1356 Beta MH 10/27 11.0 81.3 2 100 962

1357 Gamma TS 11/18 15.7 85.6 2 45 1,002

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
70

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1358 Delta TS 11/20 28.0 43.5 5 60 980

1359 Epsilon H 11/29 31.5 49.2 5 75 981

1360 Zeta TS 12/30 24.2 36.1 5 55 994

Summary: NTC = 28, NH = 15, NMH = 7, NUSLFH = 6

PWS = 160, <PWS> = 76.8, LP = 882, <LP> = 974.4

<N. Lat.> = 22.5, <W. Long.> = 66.8

2006 1361 Alberto TS 06/11 22.5 86.3 1 60 969

1362 Unnamed TS 07/17 40.0 65.1 3* 45 998

1363 Beryl TS 07/18 33.0 73.3 3 50 1,000

1364 Chris TS 08/01 16.8 58.9 4 55 1,001

1365 Debby TS 08/23 14.9 28.1 4 45 999

1366 Ernesto H 08/25 13.7 65.8 2 65 985

1367 Florence H 09/05 16.8 46.1 4 80 965

1368 Gordon MH 09/11 20.9 56.3 5 105 955

1369 Helene MH 09/14 12.9 31.9 4 105 955

1370 Isaac H 09/28 27.4 54.0 5 75 985

Summary: NTC = 10, NH = 5, NMH = 2, NUSLFH = 0

PWS = 105, <PWS> = 68.5, LP = 955, <LP> = 981.2

<N. Lat.> = 21.9, <W. Long.> = 56.6

2007 1371 Andrea SS(H) 05/06 35.5 74.0 3 65 998

1372 Barry TS 06/01 23.6 85.7 1 50 990

1373 Chantal TS 07/31 35.5 66.5 3 60 964

1374 Dean MH 08/14 11.8 38.3 4 150 907

1375 Erin TS 08/15 25.8 94.0 1 50 995

1376 Felix MH 09/01 12.1 59.4 4 150 930

1377 Gabrielle TS 09/08 30.1 71.8 3 50 1,004

1378 Humberto H 09/12 27.8 95.1 1 80 985 TX1, LA1

1379 Ingrid TS 09/13 13.7 46.7 4 40 1,002

1380 Jerry TS 09/23 36.2 46.1 5 35 1,003

1381 Karen H 09/25 10.3 37.0 4 65 988

1382 Lorenzo H 09/27 20.6 95.1 1 70 990

1383 Melissa TS 09/29 14.5 27.4 4 35 1,005

1384 Noel H 10/28 16.3 71.6 2 75 965

1385 Olga TS 12/10 18.3 61.8 2 50 1,003

Summary: NTC = 15, NH = 7, NMH = 2, NUSLFH = 1

PWS = 150, <PWS> = 68.3, LP = 907, <LP> = 981.9

<N. Lat.> = 22.1, <W. Long.> = 64.7

2008 1386 Arthur TS 05/31 17.5 87.5 2 40 1,004

1387 Bertha MH 07/03 13.1 24.0 4 105 955

1388 Cristobal TS 07/19 32.4 78.8 3 55 998

1389 Dolly H 07/20 17.8 83.6 2 85 963 TX1

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
71

Year SNBR Name Class. FSD

Genesis Location

N. Lat W. Long. PWS LP LP USLFH

1390 Edouard TS 08/04 28.1 88.5 1 55 997

1391 Fay TS 08/15 18.5 68.8 2 60 986

1392 Gustav MH 08/25 15.1 69.6 2 125 943 LA2

1393 Hanna H 08/28 20.1 58.6 5 75 977

1394 Ike MH 09/01 17.3 38.4 4 125 935 TX2, LA1

1395 Josephine TS 09/02 12.7 23.2 4 55 994

1396 Kyle H 09/25 22.0 69.4 3 75 984

1397 Laura H 09/26 39.0 35.0 5 70 991

1398 Marco TS 10/06 18.9 93.7 1 55 998

1399 Nana TS 10/12 16.0 37.1 5 35 1,004

1400 Omar MH 10/14 14.5 69.6 2 115 958

1401 Paloma MH 11/06 14.8 82.1 2 125 944

Summary: NTC = 16, NH = 9, NMH = 5, NUSLFH = 3

PWS = 125, <PWS> = 78.4, LP = 935, <LP> = 976.9

<N. Lat.> = 19.9, <W. Long.> = 63.0

Note: Group 1 (Gulf of Mexico area): 18.0N–30.0N, 80.0W–99.9W and 15.0N–19.9N, 90.0W–94.9W

Group 2 (Caribbean Sea area): 10.0N–19.9N, 60.0W–89.9W

Group 3 (East coast area): 20.0N–39.9N, 60.0W–79.9W

Group 4 (Lower N. Atlantic-Cape Verdi area): 5.0N–19.9N, 15.0W–59.9W

Group 5 (Open N. Atlantic area): 20.0N–44.9N, 15.0W–59.9W

	 P/1 means the tropical cyclone formed in the Pacific Ocean, then moved into the Gulf of Mexico.

* means it belongs in the group, even though it does not fall within the areal bounds as given above.

Table 13. Listing of North Atlantic basin tropical cyclones for the interval 1945–2008 (Continued).
72
73

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Standard Form 298 (Rev. 8-98)

Prescribed by ANSI Std. Z39-18

North Atlantic Basin Tropical Cyclone Activity in Relation

to Temperature and Decadal-Length Oscillation Patterns

Robert M. Wilson

George C. Marshall Space Flight Center

Marshall Space Flight Center, AL 35812

National Aeronautics and Space Administration

Washington, DC 20546–0001

Unclassified-Unlimited

Subject Category 47

Availability: NASA CASI (443–757–5802)

Prepared by the Science and Exploration Vehicle Office, Science and Mission Systems Office

M–1257

01–06–2009 Technical Publication

NASA/TP—2009–215796

tropical cyclone activity, North Atlantic basin, forecasting, global warming, decadal-length oscillations, Oceanic Oscillation 

Index, El Niño, La Niña, North Atlantic Oscillations, East Atlantic Index, Southern Oscillation Index, 2009 hurricane season

U U U UU 84

Yearly frequencies of North Atlantic basin tropical cyclones, their locations of origin, peak wind speeds, 

average peak wind speeds, lowest pressures, and average lowest pressures for the interval 1950–2008 are 

examined. The effects of El Niño and La Niña on the tropical cyclone parametric values are investigated. 

Yearly and 10-year moving average (10-yma) values of tropical cyclone parameters are compared against 

those of temperature and decadal-length oscillation, employing both linear and bi-variate analysis, and 

first differences in the 10-yma are determined. Discussion of the 2009 North Atlantic basin hurricane 

season, updating earlier results, is given.

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