NASA/TP—2014–218200

On the Sizes of the North Atlantic Basin

Tropical Cyclones Based on 34- and 64-kt

Wind Radii Data, 2004 –2013

Robert M. Wilson

Marshall Space Flight Center, Huntsville, Alabama

September 2014
	




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i

NASA/TP—2014 –218200

On the Sizes of the North Atlantic Basin

Tropical Cyclones Based on 34- and 64-kt

Wind Radii Data, 2004 –2013

Robert M. Wilson

Marshall Space Flight Center, Huntsville, Alabama

National Aeronautics and

Space Administration

Marshall Space Flight Center • Huntsville, Alabama 35812

September 2014
ii

Available from:

NASA STI Information Desk

Mail Stop 148

NASA Langley Research Center

Hampton, VA 23681–2199, USA

757–864–9658

This report is also available in electronic form at

<http://www.sti.nasa.gov>
iii

TABLE OF CONTENTS

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

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

3. SUMMARY ........................................................................................................................ 30

APPENDIX ............................................................................................................................. 33

REFERENCES ....................................................................................................................... 35
iv

LIST OF FIGURES

1. Yearly variation of (a) LIS(L34WR), (b) <L34WR>, (c) LIS(L34WA), 

(d) <L34WA>, (e) LIS(A34WA), and (f) <A34WA> for the interval 

2004–2013 ................................................................................................................... 17

2. Yearly variation of (a) LIS(L64WR), (b) <L64WR>, (c) LIS(L64WA), 

(d) <L64WA>, (e) LIS(A64WA), and (f) <A64WA> for the interval 

2004–2013 ................................................................................................................... 19

3. Yearly variation of the (a) total 34WA, (b) total 64WA, and (c) ratio 

(total 64WA/total 34WA) for the interval 2004–2013 ................................................... 20

4. Yearly variation of (a) <ONI>, (b) <SOI>, (c) <AMO>, (d) <MLCO2>, 

 and (e) <GLOTI> for the interval 2004–2013 ............................................................ 22

5. Scatterplots of ratio versus (a) <ONI>, (b) <SOI>, and (c) <MLCO2> ..................... 27

6. Scatterplots of (a) NH, (b) NSD, (c) LIS(L34WR), and (d) total 34WA 

versus <AMO> ........................................................................................................... 28

7. Scatterplot of <A64WA> versus <MLCO2> .............................................................. 29
v

LIST OF TABLES

1. Listing of North Atlantic basin tropical cyclones (2004–2013) including 

34- and 64-kt wind radii (in nmi) and areal data .......................................................... 3

2. Distributions ............................................................................................................... 15

3. Yearly counts and averages of NTC, NH, 34- and 64-kt wind radii and wind 

areas from HURDAT2 dataset, and selected climate-related factors for 

the interval 2004 –2013 ................................................................................................ 23

4. Yearly variation of total tropical cyclone wind areas (nmi2) for the interval 

2004 –2013 ................................................................................................................... 24

5. Summary of statistics based on comparison of tropical cyclone parameters 

and specific climate-related factors .............................................................................. 25

6. HURDAT2 data for Alex during the 2004 hurricane season, with comments .............. 34
vi
vii

LIST OF ABBREVIATIONS, ACRONYMS, SYMBOLS, AND DESIGNATORS

A34WA average 34-kt wind area for a tropical cyclone (nmi2)

<A34WA> mean yearly A34WA for all tropical cyclones in a season (nmi2)

A64WA average 64-kt wind area for a tropical cyclone (nmi2)

<A64WA> mean yearly A64WA for all tropical cyclones in a season (nmi2)

ACE accumulated cyclone energy (104 kt2)

AMO Atlantic Multidecadal Oscillation (index)

<AMO> mean yearly AMO

CO2 carbon dioxide 

DOY day of year

FHD first hurricane day

FMHD first major hurricane day

FSD first storm day

GLOTI Global Land-Ocean Temperature Index (°C)

<GLOTI> mean yearly GLOTI

H hurricane

HISACE highest individual storm ACE

HISPDI highest individual storm PDI

HURDAT hurricane database (original version)

HURDAT2 hurricane database (newer version)

L34WA largest 34-kt wind area (nmi2)
viii

LIST OF ABBREVIATIONS, ACRONYMS, SYMBOLS, AND DESIGNATORS (Continued)

<L34WA> mean yearly L34WA

L34WR largest 34-kt wind radius (nmi)

<L34WR> mean yearly L34WR

L64WA largest 64-kt wind area (nmi2)

<L64WA> mean yearly L64WA

L64WR largest 64-kt wind radius (nmi)

<L64WR> mean yearly L64WR

LIS largest individual storm

LIS(L34WA) largest individual storm of L34WA

LIS(L34WR) largest individual storm of L34WR

LIS(L64WA) largest individual storm of L64WA

LIS(L64WR) largest individual storm of L64WR

LISNSD largest individual storm of NSD

LOS length of season (days)

LP lowest pressure (mb)

<LP> mean yearly LP for all tropical cyclones in a season

LHD last hurricane day

LMHD last major hurricane day

LSD last storm day

MH major hurricane

MLCO2 Mauna Loa carbon dioxide (index)

<MLCO2> mean yearly MLCO2

NH number of hurricanes
ix

LIST OF ABBREVIATIONS, ACRONYMS, SYMBOLS, AND DESIGNATORS (Continued)

NHD number of hurricane days

<N. Lat.> mean yearly north latitude for all tropical cyclones in a season (degrees)

NMH number of major hurricanes

NMHD number of major hurricane days

NSD number of storm days

NTC number of tropical cyclones

NTCA net tropical cyclone activity (index)

NTS number of tropical storms

NUSLFH number of U.S. land-falling hurricanes

ONI Oceanic Niño Index

<ONI> mean yearly ONI

PDI power dissipation index (106 kt3)

PWS peak wind speed (kt)

<PWS> mean yearly PWS

SOI Southern Oscillation Index

<SOI> mean yearly SOI

SS substorm

total 34WA sum of the 34-kt wind areas for all tropical cyclones in a season

total 64WA sum of the 64-kt wind areas for all tropical cyclones in a season

total ACE sum of ACE for all tropical cyclones in a season

total NHD sum of NHD for all tropical cyclones in a season

total NMHD sum of NMHD for all tropical cyclones in a season

total NSD sum of NSD for all tropical cyclones in a season
x

LIST OF ABBREVIATIONS, ACRONYMS, SYMBOLS, AND DESIGNATORS (Continued)

total PDI sum of PDI for all tropical cyclones in a season

TS tropical storm

U.S. United States

USLFH U.S. land-falling hurricane

UT universal time

<W. Long.> mean yearly west longitude for all tropical cyclones in a season (degrees)
xi

NOMENCLATURE

a y-intercept

b slope

cl confidence level

r coefficient of correlation

r2 coefficient of determination

sd standard deviation 

se standard error of estimate

x independent variable

y dependent variable
xii
1

TECHNICAL PUBLICATION

ON THE SIZES OF THE NORTH ATLANTIC BASIN TROPICAL CYCLONES 

BASED ON 34- AND 64-KT WIND RADII DATA, 2004 –2013

1. INTRODUCTION

 At the end of the 2012 North Atlantic basin hurricane season, the National Hurricane Center retired the older HURDAT dataset and initiated a newer version called HURDAT2. The newer 

version reformatted the original HURDAT data and included additional data, in particular, the 

34-, 50-, and 64-kt wind radii (in nautical miles) by quadrant (northeast, southeast, southwest, and 

northwest). Presently, this tropical cyclone wind radii dataset is available only for the most recent 

interval 2004 –2013.1,2

 The purpose of this Technical Publication is (1) to examine the distributions of the 34- and 

64-kt wind radii data to determine the sizes of the wind areas for individual tropical cyclones and 

for each year during the interval 2004 –2013; (2) to determine if there are any discernible trends (i.e., 

statistically important) in the tropical cyclone wind radii and areal data during this very brief 10-year 

period; and (3) to determine the effects, if any, of specific climate-related factors3 on the tropical 

cyclone wind radii and areal data (e.g., the Oceanic Niño Index (ONI), the Southern Oscillation 

Index (SOI), the Atlantic Multidecadal Oscillation (AMO) index, the Mauna Loa Carbon Dioxide 

(MLCO2) index, and the Global Land-Ocean Temperature Index (GLOTI)).
2

2. RESULTS AND DISCUSSION

 Table 1 provides a listing of the tropical cyclones that occurred in the North Atlantic basin 

during the interval 2004 –2013. Included in the listing are some 164 tropical cyclones, of which 77 

became hurricanes (34 of the 77 hurricanes became major or intense hurricanes) and 17 struck the 

United States (U.S.) coastline with hurricane-force winds (≥64 kt). The table gives the name of each 

tropical cyclone; the class of the tropical cyclone at greatest strength, i.e., substorm (SS), tropical 

storm (TS), hurricane (H), and major hurricane (MH); the first storm day (FSD), i.e., the first day 

the tropical cyclone attained a 1-min sustained peak wind speed of at least 34 kt and the tropical 

cyclone was not classified as ‘extratropical’; the last storm day (LSD), i.e., the last day the tropical 

cyclone had a 1-min sustained peak wind speed of at least 34 kt and the tropical cyclone was not 

classified as extratropical; the genesis location, i.e., the onset location of the tropical cyclone in terms 

of its N. latitudinal and W. longitudinal position on the FSD; the group descriptor, i.e., the general 

area where the storm had its onset, where group 1 is the region of the Gulf of Mexico; group 2, the 

Caribbean Sea; group 3, the east coast near the U.S.; group 4, the lower N. Atlantic basin/Cape Verdi 

area; and group 5, the open N. Atlantic basin farther away from the U.S.; the peak wind speed (PWS) 

in kt; the lowest pressure (LP) in mb; the power dissipation index (PDI) in units of 106 kt3; the accumulated cyclone energy (ACE) in units of 104 kt2; the largest 34-kt wind radius (L34WR) in nmi; 

the largest 34-kt wind area (L34WA) in nmi2; the average 34-kt wind area (A34WA) in nmi2, i.e., the 

average area of the tropical cyclone during its lifetime based on each of the 6-hr time measurements 

at 0000, 0600, 1200, and 1800 universal time (UT); the largest 64-kt wind radius (L64WR) in nmi; 

the largest 64-kt wind area (L34WA) in nmi2; the average 64-kt wind area (A64WA) in nmi2, i.e., the 

average area of the tropical cyclone during its lifetime based on each of the 6-hr time measurements 

at 0000, 0600, 1200, and 1800 UT; the number of storm days (NSD), i.e., the number of days that 

the tropical cyclone had a sustained 1-min PWS of at least 34 kt and the storm was not classified as 

extratropical; the number of hurricane days (NHD), i.e., the number of days that the tropical cyclone 

had a sustained 1-min PWS of at least 64 kt and the storm was not classified as extratropical; the 

number of major hurricane days (NMHD), i.e., the number of days that the tropical cyclone had 

a sustained 1-min PWS of at least 96 kt and the storm was not classified as extratropical; and the 

identification of those storms that were U.S. land-falling hurricanes (USLFH), i.e., those storms that 

struck the U.S. coastline with at least minimal hurricane-force winds, identifying the states that were 

struck and the class of the storm at landfall, where classes 1 and 2 mean the tropical cyclone struck 

the U.S. with minimal hurricane-force winds, 64 –95 kt, and classes 3 through 5 mean the tropical 

cyclone struck the U.S. with major hurricane-force winds, ≥96 kt.

 At the bottom of each yearly tabular listing are the yearly summaries identifying totals, peak 

parametric values, mean parametric values, and the net tropical cyclone activity (NTCA), described 

as a percentage relative to the 1950–2000 average. For the 34- and 64-kt wind radii and areas, the LIS 

value simply means the ‘largest individual storm’ value and the values within the symbols <> mean 

the average of the yearly 34- and 64-kt wind radii and areas. Also included is the length of season 

(LOS), i.e., the inclusive elapsed time in days between the day of year (DOY) associated with the 

FSD for the first tropical cyclone of the yearly season and the DOY associated with the LSD for the 

last tropical cyclone of the yearly season.
3

Table 1. Listing of North Atlantic basin tropical cyclones (2004–2013) including 34-and 6

 wind radii (in nmi) and areal data.

2004&

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Alex MH 08/01 08/06 31.6 79.2 3 105 957 9.5 11.4 300 150,816 54,430 50 3,691 2,728 5.00 Bonnie TS 08/09 08/12 22.5 87.6 1 55 1,001 1.2 2.6 60 5,400 3,524 – – – 3.25 Charley MH 08/10 08/14 12.9 65.3 2 125

(130)

 947

 (941)

 9.0 10.6 100 21,559 14,775 50 2,847 1,234 4.75 

Danielle H 08/14 08/20 12.6 24.2 4 95 964 9.5 12.1 120 31,455 15,611 25 1,787 1,318 6.75 Earl TS 08/14 08/15 10.5 53.5 4 45 1,009 0.3 0.8 90 10,780 9,614 – – – 1.25 Frances MH 08/25 09/07 11.5 39.8 4 125 937

 (935)

48.0 45.9 175 76,537 48,968 85 14,883 7,484 12.50 

Gaston H 08/28 09/01 31.3 78.2 3 65 986

 (985)

 1.3 2.7 120 17,671 7,653 10 157 157 3.25 

Hermine TS 08/29 08/31 31.1 69.8 3 50 1,002 0.5 1.3 125 12,272 5,959 – – – 2.00 Ivan MH 09/03 09/23 9.7 30.3 4 145 910 83.5 70.4 250 130,572 50,556 100 21,795 9,262 14.75 Jeanne MH 09/14 09/27 16.4 62.6 2 105 951

 (950)

18.4 24.2 180 73,062 27,747 60 10,446 4,232 13.00 

Karl MH 09/16 09/24 11.2 32.1 4 125 938 28.5 28.4 350 324,468 107,362 90 14,844 8,823 8.25 Lisa H 09/20 10/03 13.5 35.4 5 65 987 6.3 12.2 200 88,357 18,655 20 628 628 11.75 Matthew TS 10/08 10/10 24.1 94.2 1 40 997 0.4 1.0 150 25,525 19,994 – – – 1.75 Nicole SS 10/10 10/11 31.0 66.3 3 45 986 0.5 1.2 300 204,204 85,973 – – – 1.75 Otto TS 11/29 12/02 29.6 47.9 5 45 996 0.8 1.9 275 130,082 51,701 – – – 3.00 Summary: NTC = 15, NTS = 6, NH = 9, NMH = 6, NUSLFH = 5, PWS = 145, <PWS> = 82.3, LP = 910, <LP> = 971.2, <N. Lat.> = 20.0, <W. Long.> = 57.8, Total PDI = 217.7, Total ACE = 226.7, T

= 45.50, Total NMHD = 22.25, HISPDI = 83.5, HISACE = 70.4, LISNSD = 14.75, NTCA = 231.4%, FSD = 214, LSD = 337, LOS = 124, LIS(L34WR) = 350, <L34WR> = 186, LIS(L34WA) LIS(A34WA) = 107,362, <A34WA> = 34,835, LIS(L64WR) = 100, <L64WR> = 54, LIS(L64WA) = 21,795, <L64WA> = 7,898, LIS(A64WA) = 9,262, <A64WA> = 3,985

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

	

			^ = the Hurricane Center did not make USLF, but did produce hurricane force winds over land.
4 Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2005

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Arlene TS 06/09 06/11 18.2 83.9 2 60 990

 (989)

 1.3 2.6 140 39,625 18,593 – – – 2.75 

Bret TS 06/29 06/29 20.0

(19.9)

95.8

(95.7)

1 35 1,005

(1,002)

 0.1 0.4 30 2,827 2,566 – – – 0.75 

Cindy H 07/05 07/06 25.1 90.2 1 65 992

 (991)

 0.8 1.5 90 19,792 13,188 20 628 628 1.50 

Dennis MH 07/05 07/11 13.0 65.9 2 130 930 19.4 18.8 200 79,502 37,830 55 4,359 2,548 5.75 Emily MH 07/12 07/21 11.0 46.8 4 140 929 35.7 32.9 140 40,762 24,089 60 6,244 2,764 9.25 Franklin TS 07/22 07/29 25.7 75.9 3 60 997 3.2 6.7 140 25,525 11,349 – – – 8.00 Gert TS 07/24 07/25 20.8 95.0 1 40 1,005 0.2 0.5 75 17,671 11,167 – – – 1.00 Harvey TS 08/03 08/08 29.5 68.6 3 55 994 2.6 5.4 120 26,704 13,589 – – – 5.75 Irene H 08/07 08/18 20.2 45.0 5 90 970 8.9 13.1 360 207,109 21,065 30 1,335 988 8.75 Jose TS 08/22 08/23 19.6 95.0 1 45

 (50)

1,001

 (998)

 0.2 0.4 40 3,534 2,068 – – – 0.75 

Katrina MH 08/24 08/30 24.5 76.5 3 150 902 22.1 20.0 200 105,950 37,211 90 21,049 8,814 6.00 Lee TS 08/31 08/31 29.0 50.4 5 35 1,006 0.1 0.2 60 5,655 5,655 – – – 0.50 Maria MH 09/02 09/10 21.1 49.4 5 100 962 10.3 14.3 225 119,282 50,270 75 13,254 3,969 8.00 Nate H 09/06 09/10 28.4 66.6 3 80 979 4.7 7.2 240 89,064 39,448 60 7,069 1,944 4.75 Ophelia H 09/07 09/17 27.9 78.8 3 75 976 9.8 15.7 150 53,564 30,270 45 4,595 2,544 10.75 Philippe H 09/17 09/23 13.5 54.9 4 70 985 3.3 6.0 120 23,326 10,143 15 353 353 5.75 Rita MH 09/18 09/25 22.2 72.3 3 155 897

 (895)

29.5 25.1 180 74,534 42,027 75 14,510 7,952 6.50 

Stan H 10/02 10/04 19.5 87.2 2 70 977 1.3 2.4 100 19,615 11,962 15 707 619 2.50 Unnamed SS/TS 10/04 10/05 35.9 28.5 5 45 997 0.2 0.5 90 12,723 11,427 – – – 0.75 Tammy TS 10/05 10/06 27.3 79.7 3 45 1,001 0.3 0.8 230 74,318 42,243 – – – 1.25 Vince H 10/08 10/10 32.9 20.6 5 65 988 1.4 2.7 70 15,394 9,768 15 707 707 2.75 Wilma MH 10/17 10/25 16.9 79.6 2 160 882 45.7 38.9 375 236,601 83,037 90 16,454 11,588 8.75 Alpha TS 10/22 10/23 16.5 68.5 2 45 998 0.3 0.7 45 3,809 2,307 – – – 1.00 Beta MH 10/27 10/30 11.0 81.3 2 100 962 4.8 6.5 60 9,582 5,534 15 707 707 3.75 Gamma TS 11/15 11/20 14.3 66.0 2 45 1,002 0.4 1.1 90 12,723 9,036 – – – 2.25 Delta TS 11/22 11/28 30.7 40.5 5 60 980 3.1 6.0 275 188,986 77,132 – – – 5.75 
5

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2005

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Epsilon H 11/29 12/08 31.5 49.2 5 75 981 8.3 13.4 130 41,783 24,430 35 1,787 905 9.25 Zeta TS 12/30 01/06 24.2 36.1 5 55 994 3.1 6.3 175 52,524 24,547 – – – 7.00 Summary: NTC =28, NTS = 13, NH = 15, NMH = 7, NUSLFH = 5, PWS = 160, <PWS> = 76.8, LP = 882, <LP> =974.4, <N. Lat.> = 22.5, <W. Long.> = 66.0, Total PDI = 221.1, Total ACE = 250.1, T

= 49.50, Total NMHD = 17.50, HISPDI = 45.7, HISACE = 38.9, LISNSD = 10.75, NTCA = 278.4%, FSD = 160, LSD = 371, LOS = 212, LIS(L34WR) = 375, <L34WR> = 148, LIS(L34WA) LIS(A34WA) = 83,037, <A34WA> = 23,998, LIS(L64WR) = 90, <L64WR> = 46, LIS(L64WA) = 21,049, <L64WA> = 6,251, LIS(A64WA) = 11,588, <A64WA> = 3,135

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).
6

2006

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Alberto TS 06/11 06/14 22.5 86.3 1 60 995 1.4 2.8 200 51,915 30,201 – – – 3.25 Unnamed TS 07/17 07/18 40.0 65.1 3* 45 998 0.3 0.6 60 2,827 2,827 – – – 1.00 Beryl TS 07/18 07/21 33.0 73.3 3 50 1,000 1.0 2.3 120 22,462 14,384 – – – 3.00 Chris TS 08/01 08/03 16.8 58.9 4 55 1,001 1.0 2.2 70 7,697 4,638 – – – 2.50 Debby TS 08/23 08/26 14.9 28.1 4 45 999 1.0 2.3 90 6,362 4,484 – – – 3.25 Ernesto H 08/25 09/01 13.7 65.8 2 65 985 2.8 5.7 125 24,544 8,898 10 79 79 7.00 Florence H 09/05 09/12 16.8 46.1 4 80 974 5.9 9.6 360 319,500 136,439 90 14,137 5,966 7.75 Gordon MH 09/11 09/20 20.9 56.3 5 105 955 18.3 22.2 200 56,784 25,585 70 3,848 1,794 9.50 Helene MH 09/14 09/24 12.9 31.9 4 105 955 19.4 24.3 350 320,541 93,303 100 20,577 6,584 10.75 Isaac H 09/28 10/02 27.4 54.0 5 75 985 4.0 6.5 225 80,012 33,817 35 2,376 1,495 4.75 Summary: NTC = 10, NTS = 5, NH = 5, NMH = 2, NUSLFH = 0, PWS = 105, <PWS> = 68.5, LP = 955, <LP> = 984.7, <N. Lat.> = 21.9, <W. Long.> = 56.6, Total PDI = 55.1, Total ACE = 78.5, Tot

Total NMHD = 2.00, HISPDI = 19.4, HISACE = 24.3, LISNSD = 10.75, NTCA = 85.0%, FSD = 162, LSD = 275, LOS = 114, LIS(L34WR) = 360, <L34WR> = 180, LIS(L34WA) = 320,541= 136,439, <A34WA> = 35,458, LIS(L64WR) = 100, <L64WR> = 61, LIS(L64WA) = 20,577, <L64WA> = 8,203, LIS(A64WA) = 6,584, <A64WA> = 3,184

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

* = means it belongs in the group, even though it does not fall within the areal bounds as given above.

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).
7

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2007

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Andrea SS/TS 05/09 05/10 30.8 78.7 3 50 1,001 0.4 0.9 175 56,176 25,137 – – – 1.25 Barry TS 06/01 06/02 23.6 85.7 1 50 997 0.3 0.8 80 12,017 10,309 – –- – 1.00 Chantal TS 07/31 08/01 37.1 65.5 3 45 994 0.3 0.7 175 36,776 26,517 – – – 1.00 Dean MH 08/14 08/22 11.8 38.3 4 150 907

 (905)

40.8 35.2 240 80,052 43,579 60 6,597 4,132 8.50 

Erin TS 08/15 08/16 25.8 94.0 1 35 1,003 0.1 0.4 75 4,418 3,888 – – – 0.75 Felix MH 09/01 09/05 12.1 59.4 4 150 930

 (929)

22.1 18.0 100 21,382 12,372 40 3,004 1,473 4.25 

Gabrielle TS 09/08 09/10 30.1 71.8 3 50 1,004 0.6 1.5 125 24,544 10,267 – – – 2.25 Humberto H 09/12 09/13 27.8 95.1 1 80 985 1.1 1.8 50 4,909 3,001 15 177 177 1.50 Ingrid TS 09/13 09/15 13.7 46.7 4 40 1,002 0.5 1.3 45 4,771 3,788 – – – 2.50 Jerry TS 09/23 09/24 36.2 46.1 5 35 1,003 0.2 0.7 90 19,969 16,700 – – – 1.50 Karen H 09/25 09/29 10.3 37.0 4 65 988 1.9 3.6 180 62,380 27,743 50 3,220 2,680 4.00 Lorenzo H 09/27 09/28 20.6 95.1 1 70 990 0.9 1.5 60 4,948 3,770 20 785 785 1.00 Melissa TS 09/29 09/30 14.5 27.4 4 35 1,005 0.2 0.5 60 9,189 9,189 – – – 1.00 Noel H 10/28 11/02 16.3 71.6 2 70 980 3.1 5.6 300 151,975 46,403 60 7,069 3,701 5.50 Olga TS 12/11 12/12 18.4 64.7 2 50 1,003 0.6 1.3 300 94,739 64,686 – – – 1.75 Sample: NTC = 15, NTS = 9, NH = 6, NMH = 2, NUSLFH = 1, PWS = 150, <PWS> = 65.0, LP = 907, <LP> = 986.1, <N. Lat.> = 21.9, <W. Long.> = 65.1, Total PDI = 73.1, Total ACE = 73.8, Total 

Total NMHD = 6.00, HISPDI = 40.8, HISACE = 35.2, LISNSD = 8.50, NTCA = 98.6%, FSD = 129, LSD = 346, LOS = 218, LIS(L34WR) = 300, <L34WR> = 130, LIS(L34WA) = 151,975, <= 64,686, <A34WA> = 20,490, LIS(L64WR) = 60, <L64WR> = 41, LIS(L64WA) = 7,069, <L64WA> = 3,475, LIS(A64WA) = 4,132, <A64WA> = 2,158

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).
8

2008#

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Arthur TS 05/31 06/01 17.5 87.5 2 40 1,004 0.3 0.8 225 55,469 37,961 – – – 1.50 Bertha MH 07/03 07/20 13.1 24.0 4 105

(110)

 955

 (952)

20.1 28.4 200 78,461 31,110 45 4,064 1,340 17.00 

Cristobal TS 07/19 07/23 32.4 78.8 3 55 998 1.8 3.7 110 15,158 10,490 – – – 4.00 Dolly H 07/20 07/24 17.8 83.6 2 85 967

 (963)

3.3 5.4 150 53,014 35,445 30 1,649 1,099 4.50 

Edouard TS 08/04 08/05 28.1 88.5 1 55 996 0.8 1.7 60 10,073 5,341 – – – 2.00 Fay TS 08/15 08/23 18.5 68.8 2 60 986 3.5 7.3 150 40,762 17,415 – – – 8.25 Gustav MH 08/25 09/02 15.1 69.6 2 125

(135)

 943

 (941)

16.0 18.2 220 104,929 31,511 70 8,639 4,685 8.00 

Hanna H 08/28 09/07 20.1 58.6 5 75 977 5.6 10.4 275 133,066 57,904 40 2,513 2,068 9.75 Ike MH 09/01 09/14 17.3 38.4 4 125 935 37.7 39.2 240 133,596 57,883 110 23,110 7,332 13.00 Josephine TS 09/02 09/05 12.7 23.2 4 55 994 1.4 3.1 150 25,525 15,741 – – – 3.75 Kyle H 09/25 09/29 22.0 69.4 3 75 984 3.4 5.4 210 83,193 42,283 75 9,759 5,366 4.00 Laura TS 09/29 10/01 37.0 47.0 5 50 994 1.1 2.2 270 168,546 118,320 – – – 2.25 Marco TS 10/06 10/07 18.9 93.7 1 55 998 0.7 1.3 15 707 436 – – – 1.25 Nana TS 10/12 10/13 16.0 37.1 5 35 1,004 0.2 0.5 100 12,272 8,929 – – – 1.00 Omar MH 10/14 10/18 14.5 69.6 2 115 958 7.2 9.3 135 29,158 20,546 40 1,865 1,139 4.50 Paloma MH 11/06 11/09 14.8 82.1 2 125 944 8.9 9.2 120 24,190 11,805 25 1,963 1,333 3.50 Summary: NTC = 16, NTS = 8, NH = 8, NMH = 5, NUSLFH = 3, PWS = 125, <PWS> = 77.2, LP = 935, <LP> = 977.3, <N. Lat.> = 19.7, <W. Long.> = 63.7, Total PDI = 112.0, Total ACE = 146.1, T

Total NMHD = 7.50, HISPDI = 37.7, HISACE = 39.2, LISNSD = 17.00, NTCA = 161.8%, FSD = 152, LSD = 314, LOS = 163, LIS(L34WR) = 275, <L34WR> = 164, LIS(L34WA) = 168,54= 118,320, <A34WA> = 31,445, LIS(L64WR) = 110, <L64WR> = 54, LIS(L64WA) = 23,110, <L64WA> = 6,695, LIS(A64WA) = 7,332, <A64WA> = 3,045

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

	

			

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).
9

2009&

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Ana TS 08/12 08/16 14.4 33.3 4 35 1,003 0.3 0.9 60 5,655 4,090 – – – 1.75 Bill MH 08/15 08/24 11.2 34.5 4 115 943 25.3 26.5 275 162,067 82,425 100 16,513 7,188 8.75 Claudette TS 08/16 08/17 28.2 84.2 1 50 1,005 0.3 0.7 80 6,538 5,002 – – – 1.00 Danny TS 08/26 08/29 24.6 70.1 3 50 1,006 0.9 2.0 180 57,432 40,203 – – – 2.75 Erika TS 09/01 09/03 16.7 57.3 4 45 1,004 0.5 1.3 200 49,087 28,765 – – – 2.00 Fred MH 09/08 09/12 11.7 25.4 4 105 958 8.1 9.9 105 22,266 14,556 25 1,649 1,242 4.75 Grace TS 10/04 10/06 38.5 29.5 5 55 986 1.0 2.0 45 4,771 4,374 – – – 2.00 Henri TS 10/06 10/08 16.1 50.5 4 45 1,005 0.5 1.2 90 9,189 4,396 – – – 2.00 Ida H 11/04 11/10 11.4 81.8 2 90 975 5.7 8.1 175 53,014 21,389 30 1,237 639 5.00 Summary: NTC = 9, NTS = 6, NH = 3, NMH = 2, NUSLFH = 0, PWS = 115, <PWS> = 65.6, LP = 943, <LP> = 987.2, <N. Lat.> = 19.2, <W. Long.> = 51.8, Total PDI = 42.6, Total ACE = 52.6, Tota

Total NMHD = 3.50, HISPDI = 25.3, HISACE = 26.5, LISNSD = 8.75, NTCA = 68.6%, FSD = 224, LSD = 314, LOS = 91, LIS(L34WR) = 275, <L34WR> = 134, LIS(L34WA) = 162,067, <= 82,425, <A34WA> = 22,800, LIS(L64WR) = 100, <L64WR> = 52, LIS(L64WA) = 16,513, <L64WA> = 6,466, LIS(A64WA) = 7,188, <A64WA> = 3,023

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

	

			

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).
10

2010#

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Alex H 06/26 07/01 16.7 84.9 2 90

 (95)

 948

 (946)

 4.9 7.7 180 75,477 28,108 50 3,024 1,859 5.75 

Bonnie TS 07/23 07/23 23.1

(23.0)

75.9

(75.7)

3 40 1,005 0.1 0.4 75 7,599 4,955 – – – 0.75 

Colin TS 08/03 08/07 13.7 46.6 4 50 1,006

(1,005)

 1.1 2.8 120 19,262 10,398 – – – 4.75 

Danielle MH 08/22 08/30 11.8 33.1 4 115 942 18.0 21.1 270 182,369 61,160 75 10,073 4,936 8.75 Earl MH 08/25 09/04 14.3 29.7 4 125 927 26.7 27.7 220 112,783 55,927 80 12,959 8,342 10.50 Fiona TS 08/30 09/03 14.9 47.7 4 55 998 1.4 3.1 120 20,499 12,620 – – – 4.25 Gaston TS 09/01 09/01 12.7 35.0 4 35 1,005 0.1 0.2 35 962 962 – – – 0.50 Hermine TS 09/06 09/07 21.8 95.1 1 55

 (60)

 990

 (989)

 0.8 1.6 90 13,744 10,516 – – – 1.75 

Igor MH 09/08 09/21 13.8 23.3 4 135 924 44.5 41.9 400 414,298 124,817 90 16,081 9,488 12.25 Julia MH 09/12 09/20 13.1 22.1 4 120 948 13.0 15.5 210 72,276 32,565 30 2,042 1,728 8.00 Karl MH 09/14 09/18 18.1 83.6 1 110 956 4.9 6.3 90 20,420 7,903 20 982 652 3.50 Lisa H 09/21 09/26 16.8 31.9 4 75 982 2.1 4.1 50 5,184 4,336 10 236 236 4.75 Matthew TS 09/23 09/25 13.9 76.2 2 50 998 0.7 1.5 150 33,399 16,859 – – – 2.00 Nicole TS 09/28 09/29 20.4 83.0 1 40 995 0.3 0.7 300 141,372 98,960 – – – 1.25 Otto H 10/06 10/10 22.6 67.8 3 75 976 3.4 5.4 190 48,066 35,039 30 1,374 1,178 3.75 Paula H 10/11 10/15 14.4 82.5 2 90 981 5.6 7.5 50 7,108 5,518 20 844 436 4.00 Richard H 10/21 10/25 16.7 80.6 2 85 977 3.1 5.0 90 15,001 8,699 15 511 358 4.25 Shary H 10/29 10/30 26.8 63.0 3 65 989 1.2 2.1 90 16,454 14,297 10 79 79 1.75 Tomas H 10/29 11/07 9.8 55.3 4 85 982 7.6 11.9 150 40,252 19,017 30 1,414 762 8.75 Summary: NTC = 19, NTS = 7, NH = 12, NMH = 5, NUSLFH = 0, PWS = 135, <PWS> = 78.7, LP = 924, <LP> = 975.2, <N. Lat.> = 16.6, <W. Long.> = 58.8, Total PDI = 139.5, Total ACE = 166.5, 

= 38.50, Total NMHD = 11.00, HISPDI = 44.5, HISACE = 41.9, LISNSD = 12.25, NTCA = 230.9%, FSD = 177, LSD = 311, LOS = 135, LIS(L34WR) = 400, <L34WR> = 152, LIS(L34WALIS(A34WA) = 124,817, <A34WA> = 29,087, LIS(L64WR) = 90, <L64WR> = 38, LIS(L64WA) = 16,081, <L64WA> = 4,135, LIS(A64WA) = 9,488, <A64WA> = 2,505

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

	

			

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).
11

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2011#

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Arlene TS 06/28 06/30 20.7 93.5 1 55 993 0.9 1.9 120 25,211 16,973 – – – 2.25 Bret TS 07/18 07/21 27.5 78.1 3 60 995 1.5 3.3 60 8,207 5,994 – – – 4.00 Cindy TS 07/20 07/22 33.4 57.0 5 60 994 1.2 2.3 90 13,607 11,430 – – – 2.50 Don TS 07/27 07/30 22.0 86.7 1 45 997 0.7 1.6 60 4,084 3,644 – – – 2.50 Emily TS 08/02 08/07 14.9 61.4 2 45 1,003 1.0 2.1 100 15,099 10,061 – – – 3.25 Franklin TS 08/13 08/13 37.6 61.1 3 40 1,004 0.1 0.3 60 4,084 4,084 – – – 0.50 Gert TS 08/14 08/16 27.7 62.3 3 55 1,000 0.9 1.9 60 7,952 5,675 – – – 2.25 Harvey TS 08/19 08/22 15.9 83.4 2 55 994 0.7 1.5 70 3,848 2,341 – – – 2.00 Irene MH 08/21 08/28 15.0 59.0 4 105 942 15.4 18.8 280 132,732 76,721 80 13,980 7,168 8.00 Jose TS 08/27 08/28 27.9 63.4 3 40 1,006 0.3 0.8 45 3,181 2,163 – – – 1.50 Katia MH 08/30 09/10 11.0 29.6 4 120 942 22.5 27.0 250 149,697 56,515 80 12,959 5,597 11.50 Unnamed TS 09/01 09/02 37.4 63.7 3 40 1,002 0.3 0.8 60 5,655 5,367 – – – 1.50 Lee TS 09/02 09/05 27.2 91.4 1 50 986 0.7 1.8 250 95,622 67,860 – – – 2.75 Maria H 09/07 09/16 11.9 37.5 4 70 983 4.8 9.2 300 133,596 38,149 60 2,827 2,278 9.00 Nate H 09/07 09/11 20.3 92.9 1 65 994 2.3 4.4 120 28,451 18,212 40 1,257 1,257 4.25 Ophelia MH 09/21 10/03 12.5 39.7 4 120 940 15.9 18.7 220 71,079 49,913 40 3,142 1,907 9.75 Philippe H 09/24 10/08 11.1 26.1 4 80 976 9.3 15.9 90 19,969 12,150 30 2,042 1,066 13.75 Rina MH 10/24 10/28 16.0 81.9 2 100 966 8.2 10.1 100 22,934 14,591 25 1,433 853 4.75 Sean TS 11/08 11/11 27.7 69.8 3 55 982 1.9 3.7 330 185,197 92,686 – – – 3.75 Summary: NTC = 19, NTS = 12, NH = 7, NMH = 4, NUSLFH = 1, PWS = 120, <PWS> = 66.3, LP = 940, <LP> =9,842, <N. Lat.> = 22.0, <W. Long.> = 65.2, Total PDI = 88.6, Total ACE = 126.1, T

Total NMHD = 4.50, HISPDI = 22.5, HISACE = 27.0, LISNSD = 13.75, NTCA = 144.9%, FSD = 179, LSD = 315, LOS = 137, LIS(L34WR) = 330, <L34WR> = 140, LIS(L34WA) = 185,19= 92,686, <A34WA> = 26,028, LIS(L64WR) = 80, <L64WR> = 51, LIS(L64WA) = 13,980, <L64WA> = 5,377, LIS(A64WA) = 7,168, <A64WA> = 2,875

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

	

			
12Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2012

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Alberto TS 05/19 05/22 32.5 77.3 3 50 995 0.8 1.9 60 5,105 3,560 – – – 3.00 Beryl TS 05/26 05/30 32.3 75.0 3 60 992 1.2 2.5 120 23,562 17,335 – – – 3.00 Chris H 06/18 06/22 38.0 61.3 3 75 974 2.3 4.1 80 12,488 10,011 20 785 602 3.75 Debby TS 06/23 06/26 25.5 87.6 1 55 990 1.3 2.9 220 72,021 46,272 – – – 3.75 Ernesto H 08/02 08/10 13.0 53.6 4 85 973 5.4 9.2 140 35,893 17,872 30 1,100 904 7.75 Florence TS 08/04 08/06 14.1 28.6 4 50 1,002 0.7 1.5 70 8,954 5,370 – – – 2.00 Gordon H 08/16 08/20 30.5 55.4 5 95 965 6.4 8.6 110 29,060 17,709 30 2,042 1,737 4.75 Helene TS 08/07 08/18 20.3 95.9 1 40 1,004 0.1 0.3 30 707 668 – – – 0.50 Isaac H 08/21 08/30 15.2 53.1 4 70 965 6.1 10.8 200 83,331 50,571 60 5,655 4,668 9.25 Joyce TS 08/23 08/23 14.8 41.1 4 35 1,006 0.1 0.2 180 50,894 36,757 – – – 0.50 Kirk H 08/29 09/02 24.0 44.5 5 90 970 5.3 7.7 120 17,122 8,215 15 609 454 5.00 Leslie H 08/30 09/11 13.8 42.6 4 70 968 7.8 16.3 270 157,629 56,940 30 2,121 1,033 12.00 Michael MH 09/04 09/11 26.2 43.0 5 100 964 13.5 16.7 70 13,352 7,765 20 1,119 792 7.50 Nadine H 09/12 10/03 17.5 44.8 4 80 978 15.6 26.3 350 170,746 58,199 40 2,278 1,283 20.75 Oscar TS 10/03 10/05 18.2 41.8 4 45 994 0.6 1.5 180 40,841 35,863 – – – 2.00 Patty TS 10/11 10/13 25.4 72.2 3 40 1,005 0.4 1.1 60 5,498 3,475 – – – 2.00 Rafael H 10/12 10/17 14.7 62.7 2 80 969 5.0 7.4 270 137,837 52,143 60 6,205 3,283 5.00 Sandy H 10/22 10/29 12.7 78.7 2 100 940 12.8 16.1 480 541,296 209,563 180 43,118 15,908 7.50 Tony TS 10/24 10/25 26.5 49.6 5 45 1,000 0.5 1.2 90 12,174 7,674 – – – 1.75 Summary: NTC = 19, NTS = 9, NH = 10, NMH = 1, NUSLFH = 2^, PWS = 100, <PWS> = 66.6, LP = 940, <LP> = 981.8, <N. Lat.> = 21.9, <W. Long.> = 58.4, Total PDI = 85.9, Total ACE = 136.3, 

Total NHD = 29.75, Total NMHD = 0.25, HISPDI = 15.6, HISACE = 26.3, LISNSD = 20.75, NTCA = 124.1%, FSD = 140, LSD = 303, LOS = 164, LIS(L34WR) = 480, <L34WR> = 163, L74,658, LIS(A34WA) = 209,563, <A34WA> = 33,998, LIS(L64WR) = 180, <L64WR> = 49, LIS(L64WA) = 43,118, <L64WA> = 6,503, LIS(A64WA) = 15,908, <A64WA> = 3,066

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).

^ = the Hurricane Center did not make USLF, but did produce hurricane-force winds over land.
13

Table 1. Listing of North Atlantic basin tropical cyclones (2004 –2013) including 34- and 64-kt 

 radii (in nmi) and areal data (Continued).

2013

Name Class FSD LSD

Genesis Location

N. Lat. W. Long. Group PWS LP PDI ACE L34WR L34WA A34WA L64WR L64WA A64WA NSD 

Andrea TS 06/05 06/07 25.1 86.6 1 55 992 0.9 1.9 120 33,301 19,978 – – – 2.00 Barry TS 06/19 06/20 19.5 94.0 1 40 1,003 0.4 0.9 70 7,226 5,388 – – – 1.25 Chantal TS 07/07 07/10 9.3 41.4 4 55 1,003 1.1 2.5 80 12,881 7,751 – – – 3.25 Dorian TS 07/24 07/27 13.5 27.1 4 50 1,002 1.1 2.6 60 9,582 3,787 – – – 3.50 Erin TS 08/15 08/18 14.1 24.6 4 40 1,006 0.6 1.5 60 7,618 3,273 – – – 3.00 Fernand TS 08/25 08/26 18.9 95.1 1 50 1,001 0.4 0.9 30 2,827 2,251 – – – 0.75 Gabrielle TS 09/10 09/13 29.0 65.0 3 55 1,003 0.8 1.7 100 17,750 11,318 – – – 2.50 Humberto H 09/09 09/18 13.3 22.4 4 80 979 5.3 8.9 200 81,132 33,353 40 2,985 2,469 8.00 Ingrid H 09/13 09/16 19.3 95.1 1 75 983 3.2 5.2 90 13,430 9,615 30 1,021 609 3.50 Jerry TS 09/30 10/03 27.2 46.8 3 45 1,005 0.7 1.9 60 6,440 4,168 – – – 3.50 Karen TS 10/03 10/05 21.5 86.8 1 55 998 1.2 2.6 120 24,347 14,751 – – – 2.75 Lorenzo TS 10/21 10/23 28.2 55.6 5 45 1,000 0.7 1.6 60 8,168 7,163 – – – 2.50 Melissa TS 11/18 11/21 29.1 53.4 5 55 980 1.7 3.5 270 153,388 96,245 – – – 3.50 Unnamed SS 12/05 12/07 32.4 27.5 5 45 997 0.6 1.5 300 134,225 55,842 – – – 2.25 Summary: NTC = 14, NTS = 12, NH = 2, NMH = 0, NUSLFH = 0, PWS = 80, <PWS> = 53.2, LP = 979, <LP> = 996.6, <N. Lat.> = 21.5, <W. Long.> = 58.7, Total PDI = 18.7, Total ACE = 37.2, Tot

Total NMHD = 0.0, HISPDI = 5.3, HISACE = 8.9, LISNSD = 8.00, NTCA = 46.5%, FSD = 156, LSD = 341, LOS = 186, , LIS(L34WR) = 300, <L34WR> = 116, LIS(L34WA) = 153,388, <L= 96,245, <A34WA> = 1,963, LIS(L64WR) = 40, <L64WR> = 35, LIS(L64WA) = 2,985, <L64WA> = 2,003, LIS(A64WA) = 2,469, <A64WA> = 1,509

Notes:

Group 1 (Gulf of Mexico area): 18.0° N.–30.0° N., 80.0° W.–99.9° W., and 15.0° N.–19.9° N., 90.0° W.–94.9° W.Group 2 (Caribbean Sea area): 10.0° N.–19.9° N., 60.0° W.–89.9° W.Group 3 (East coast area): 20.0° N.–39.9° N., 60.0° W.–79.9° W.Group 4 (Lower N. Atlantic–Cape Verdi area): 5.0° N.–19.9° N., 15.0° W.–59.9° W.Group 5 (Open N. Atlantic area): 20.0° N.–46.0° N., 15.0° W.–59.9° W.PDI = sum of wind speed cubed (in units of 10×106 kt3).

ACE = sum of wind speed squared (in units of 10×104 kt2).
14

 As an example, the HURDAT2 dataset shows that the first tropical cyclone for the 2004 

hurricane season (Alex) had its onset at 1800 UT on August 1, marking its FSD and also the FSD 

for the 2004 hurricane season (DOY 214). The onset location at FSD was 31.6° N. and 79.2° W., 

occurring in the general region classified as group 3, the east coast near the U.S. The PWS = 105 kt 

and LP = 957 mb occurred on August 5 at 0000 and 0600 UT, classifying it as an MH. The LSD for 

Alex occurred on August 6 at 1200 UT (DOY 219). Hence, its lifetime as a tropical cyclone spanned 

20 time measurements or 5 days (NSD; 4 time measurements equals 1 day). During its lifetime, Alex 

had at least minimal hurricane-force winds for 13 time measurements or 3.25 days (NHD), and it 

had major hurricane-force winds (PWS ≥96 kt) for 3 time measurements or 0.75 days (NMHD). 

Although the hurricane’s center did not actually make a direct U.S. landfall, Alex did produce minimal hurricane-force winds over North Carolina; hence, it is classified as an USLFH and marked 

with the symbol ^. Its PDI (i.e., the sum of the peak 1-min sustained wind speeds cubed over its 

lifetime) measured 9.5 (×106 kt3) and its ACE (i.e., the sum of the peak 1-min sustained wind speeds 

squared over its lifetime) measured 11.4 (×104 kt2). The L34WR for Alex measured 300 nmi (from 

August 5 at 1200 UT through August 6 at 1200 UT) and the L34WA during its lifetime measured 

150,816 nmi2 (on August 5 at 1200 UT). The A34WA (based on the 20 time measurements) measured 

54,430 nmi2. The L64WR for Alex measured 50 nmi (from August 4 at 0600 UT through August 6 

at 0600 UT), the L64WA measured 3,691 nmi2 (from August 5 at 0000 UT through August 5 at 1200 

UT) and the A64WA measured 2,728 nmi2. (The appendix describes the methodology employed here 

for determining the areal values, using Alex as an example.)

 Continuing the example, the 2004 hurricane season had NTC = 15, NTS = 6, NH = 9, 

NMH = 6, and NUSLFH = 5. Also, it had PWS = 145 kt (Ivan) and LP = 910 mb (Ivan); mean PWS 

(<PWS>) equal to 82.3 kt and mean LP (<LP>) equal to 971.2 mb for the 15 tropical cyclones; 

mean latitudinal (<N. Lat.>) and longitudinal (<W. Long.>) onset positions equal to 20.0° N. and 

57.8° W., respectively, for the 15 tropical cyclones; and total PDI and total ACE (i.e., the sum of all 

yearly individual storm PDI and ACE values) equal to 217.7 (×106 kt3) and 226.7 (×104 kt2), respectively. Because the LSD of the yearly hurricane season occurred on December 2 (DOY 337), the LOS 

for the 2004 hurricane season measures 124 days (i.e., LOS equals the inclusive elapsed time between 

FSD for Alex and LSD for Otto). The total NSD, total NHD, and total NMHD measure 93.00, 

45.50, and 22.25 days, respectively. The highest individual storm PDI (HISPDI) and highest individual storm ACE (HISACE) measure 83.5 (×106 kt3; Ivan) and 70.4 (×104 kt2; Ivan), respectively. The 

longest individual storm in the number of storm days (LISNSD) measures 14.75 days (Ivan). Finally, 

the NTCA for the 2004 hurricane season measures 231.4%, meaning that it is more than double 

the mean NTCA for the base period 1950 –2000. (The values for PWS and LP contained inside the 

parentheses are the actual PWS and LP values for the storms as recorded in the HURDAT2 dataset; 

however, because these values occurred at times other than the 0000, 0600, 1200, or 1800 UT time 

fiduciaries, they were not used in the computation of <PWS> or <LP>.)

 Because this study deals primarily with the 34- and 64-kt wind radii as reported in the 

HURDAT2 dataset associated with the 164 tropical cyclones, including the 77 tropical cyclones that 

attained hurricane strength during the interval 2004 –2013, most of the data presented in table 1 will 

not be discussed. Instead, the data are shown here merely for completeness.3–6
15

 Table 2 gives the distributions of the (a) L34WR, (b) L34WA, (c) A34WA, (d) L64WR, 

(e) L64WA, and (f) A64WA. All distributions have rightward tails, with hurricane Sandy being the 

largest individual tropical cyclone in all distributions. For the 164 tropical cyclones that occurred in 

the interval 2004 –2013, the largest single grouping for L34WR is L34WR = 50–99 nmi (50/164 = 30%), 

with 135 of the 164 tropical cyclones (82%) having L34WR <300 nmi. The two largest tropical 

cyclones in terms of L34WR are Igor (2010) and Sandy (2012), having largest 34-kt wind radii of 

400 and 480 nmi, respectively.

Table 2. Distributions.

L34WR (n = 164) L34WA (n = 164) A34WA (n = 164)

Range

(nmi) Frequency

Range

(nmi2) Frequency

Range

(nmi2) Frequency

 0–49 10 0–49,999 99 0–24,999 102

 50–99 50 50,000–999,999 30 25,000–49,999 32

 100–149 33 100,000–149,999 15 50,000–74,999 16

 150–199 20 150,000–199,999 10 75,000–99,999 9

 200–249 22 200,000–249,999 4 100,000–124,999 3

 250–299 13 250,000–299,999 1 125,000–149,999 1 (Florence, 2006)

 300–349 8 300,000–349,999 3 150,000–174,999 –

 350–399 6 350,000–399,999 – 175,000–199,999 –

 400–449 1 (Igor, 2010) 400,000–449,999 1 (Igor, 2010) 200,000–224,999 1 (Sandy, 2012)

 450–499 1 (Sandy, 2012) 450,000–499,999 –

500,000–549,999 1 (Sandy, 2012)

L64WR (n = 77) L64WA (n = 77) A64WA (n = 77)

Range

(nmi) Frequency

Range

(nmi2) Frequency

Range

(nmi2) Frequency

 0–24 18 0–4,999 51 0–2,499 48

 25–49 26 5,000–9,999 8 2,500–4,999 13

 50–74 15 10,000–14,999 10 5,000–7,499 8

 75–99 13 15,000–19,999 3 7,500–9,999 6

 100–124 4 20,000–24,999 4 10,000–12,499 1 (Wilma, 2005)

 125–149 – 25,000–29,999 – 12,500–14,999 –

 150–174 – 30,000–34,999 – 15,000–17,499 1 (Sandy, 2012)

 175–199 1 (Sandy, 2012) 35,000–39,999 –

 40,000–44,999 1 (Sandy, 2012)

 For L34WA, the largest single grouping is L34WA <50 × 103 nmi2, accounting for 99 of the 

164 tropical cyclones (60%). Again, the two largest tropical cyclones in terms of L34WA are Igor 

(2010) and Sandy (2012), having the largest 34-kt wind area of about 414 × 103 and 541 × 103 nmi2, 

respectively.

 For A34WA, the largest single grouping is A34WA <25 × 103 nmi2, accounting for 102 of 

the 164 tropical cyclones (62%). The two largest tropical cyclones in terms of A34WA are Florence (2006) and Sandy (2012), having the largest average 34-kt wind area of about 136 × 103 and 

210 × 103 nmi2, respectively.
16

 For the 77 hurricanes during the interval 2004 –2013, the largest single grouping for L64WR is 

L64WR = 25– 49 nmi (26/77 = 34%), with 72 of 77 (94%) having L64WR <100 nmi. The largest storm 

in terms of L64WR is hurricane Sandy (2012), having the largest 64-kt wind radius of 180 nmi.

 For L64WA, the largest single grouping is L64WA <5 × 103 nmi2, accounting for 51 of the 77 

hurricanes (66%). Again, the largest storm in terms of L64WA is hurricane Sandy (2012), having the 

largest 64-kt wind area of about 43 × 103 nmi2.

 For A64WA, the largest single grouping is A64WA <2.5 × 103 nmi2, accounting for 48 of the 

77 hurricanes (62%). The two largest hurricanes in terms of A64WA are hurricanes Wilma (2005) 

and Sandy (2012), having the largest average 64-kt wind area of about 12 × 103 and 16 × 103 nmi2, 

respectively.

 Figure 1 depicts the yearly variation of (a) LIS(L34WR), (b) <L34WR>, (c) LIS(L34WA), 

(d) <L34WA>, (e) LIS(A34WA), and (f) <A34WA> for the interval 2004 –2013. Concerning 

LIS(L34WR), its mean measures about 345 nmi, having sd = 64 nmi and extremes of about 275 nmi in 

2008 (Hanna) and 2009 (Bill) and 480 nmi in 2012 (Sandy). Concerning <L34WR>, its mean measures 

about 151 nmi, having sd = 22 nmi and extremes of 116 nmi in 2013 and 186 nmi in 2004. Although, 

to the eye, a downward trend in <L34WR> is suggested between 2004 and 2013, the inferred regression (not shown) is found to be only of marginal statistical importance (confidence level cl >90%). 

Concerning LIS(L34WA), its mean measures about 266 × 103 nmi2, having sd = 132 × 103 nmi2 and 

extremes of 152 × 103 nmi2 in 2007 (Noel) and 54 × 103 nmi2 in 2012 (Sandy). Concerning <L34WA>, 

its mean measures about 60 × 103 nmi2, having sd = 19 × 103 nmi2 and extremes of about 37 × 103

nmi2 in 2013 and 89 × 103 nmi2 in 2006. Concerning LIS(A34WA), its mean measures about 

112 × 103 nmi2, having sd = 41 × 103 nmi2 and extremes of about 65 × 103 nmi2 in 2007 (Olga) and 

210 × 103 nmi2 in 2012 (Sandy). Concerning <A34WA>, its mean measures about 26 × 103 nmi2, having 

sd = 10 × 103 nmi2 and extremes of about 2 × 103 nmi2 in 2013 and 35 × 103 nmi2 in 2004.
17

2000 2005 2010 2015

Year

500

0

200

150

100

5105

105

105

5104

LIS(L34WR) <L34WR> <L34WA>

(a)

(b)LIS(L34WA) LIS(A34WA) <A34WA>

(c)

(d)

(e)

(f)

104

3105

2105

105

5104

104

mean=344.5 nmi

sd=63.7 nmi

mean=151.3 nmi

sd=22.3 nmi

mean=265,837.7 nmi2

sd=132,308.2 nmi2

mean=60,103.9 nmi2

sd=19,157.0 nmi2

mean=111,558.0 nmi2

sd=40,706.2 nmi2

mean=26,010.2 nmi2

sd=9,961.3 nmi2

Sandy

Igor

Sandy

Igor

Sandy

Igor

Karl

Laura Florence

Florence

Wilma

Hanna Bill

Noel

Olga

Figure 1. Yearly variation of (a) LIS(L34WR), (b) <L34WR>, (c) LIS(L34WA), 

 (d) <L34WA>, (e) LIS(A34WA), and (f) <A34WA> for the interval 

 2004–2013.
18

 Similarly, figure 2 depicts the yearly variation of (a) LIS(L64WR), (b) <L64WR>, 

(c) LIS(L64WA), (d) <L64WA>, (e) LIS(A64WA), and (f) <A64WA> for the interval 2004 –2013. 

Concerning LIS(64WR), its mean measures about 95 nmi, having sd = 37 nmi and extremes of about 

40 nmi in 2013 (Humberto) and 180 nmi in 2012 (Sandy). Concerning <L64WR>, its mean measures about 48 nmi, having sd = 8 nmi and extremes of 35 nmi in 2013 and 61 nmi in 2006. Again, 

although to the eye there possibly appears a downward trend in <L64WR> between 2004 and 2013, 

the inferred regression (not shown) is found to be only of marginal statistical importance. Concerning LIS(L64WA), its mean measures about 19 × 103 nmi2, having sd = 11 × 103 nmi2 and extremes 

of 3 × 103 nmi2 in 2013 (Humberto) and 43 × 103 nmi2 in 2012 (Sandy). Concerning <L64WA>, its 

mean measures about 6 × 103 nmi2, having sd = 2 × 103 nmi2 and extremes of about 2 × 103 nmi2 in 

2013 and 8 × 103 nmi2 in 2006. Concerning LIS(A64WA), its mean measures about 8 × 103 nmi2, having sd = 4 × 103 nmi2 and extremes of about 2 × 103 nmi2 in 2013 (Humberto) and 16 × 103 nmi2 in 2012 

(Sandy). Concerning <A64WA>, its mean measures about 3 × 103 nmi2, having sd = 0.7 × 103 nmi2

and extremes of about 2 × 103 nmi2 in 2013 and 4 × 103 nmi2 in 2004.
19

200

150

100

50

100

50

5104

104

15103

104

5103

104

5103

5103

0

2000 2005 2010 2015

Year

LIS(L64WR) <L64WR> <L64WA>

(a)

(b)LIS(L64WA) LIS(A64WA) <A64WA>

(c)

(d)

(e)

(f)

mean=95.0 nmi

sd=36.6 nmi

mean=48.1 nmi

sd=8.1 nmi

mean=18,627.7 nmi2

sd=10,803.4 nmi2

mean=5,700.6 nmi2

sd=1,966.2 nmi2

mean=8,111.9 nmi2

sd=3,777.8 nmi2

mean=2,848.5 nmi2

sd=666.0 nmi2

Sandy

Sandy

Sandy

Ike

Igor

Wilma

Humberto

Humberto

Humberto

Figure 2. Yearly variation of (a) LIS(L64WR), (b) <L64WR>, (c) LIS(L64WA),

 (d) <L64WA>, (e) LIS(A64WA), and (f) <A64WA> for the interval 2004–2013.
20

 Figure 3 displays the yearly variation of the (a) total 34WA, (b) total 64WA, and (c) ratio 

(i.e., total 64WA/total 34WA) for the interval 2004–2013. For total 34WA, its mean measures about 

174 × 106 nmi2, having sd = 141 × 106 nmi2 and extremes of 4.6 × 106 nmi2 in 2013 and 423 × 106 nmi2 in 

2010. For total 64WA, its mean measures about 3 × 106 nmi2, having sd = 3× 106 nmi2 and extremes of 

0.04 × 106 nmi2 in 2013 and 9 × 106 nmi2 in 2005. For ratio, its mean measures 0.017, having sd = 0.008 

and extremes of 0.034 in 2004 and 0.008 in 2013. Interestingly, during the brief 10-year interval of 

2004 –2013, there possibly exists an apparent decrease in ratio over time, as given by the inferred 

regression equation y = 4.338 – 0.002x, having a coefficient of correlation r = –0.847, a coefficient of 

determination r2 = 0.717, a standard error of estimate se = 0.006, and cl >98%. Hence, presuming the 

validity of the inferred regression, the year 2014 hurricane season is suggested to have a ratio of total 

64-kt wind area to total 34-kt wind area equal to about 0.005 ± 0.006 (the ±1 se prediction interval). 

(The yearly total 34-kt wind area is found by multiplying the <A34WA> by the total number of timetagged measurements, equal to 4 times NSD, then multiplying this quantity by the NTC. Similarly, 

the yearly total 64-kt wind area is found by multiplying the <A64WA> by the total number of timetagged measurements, equal to 4 times NHD, then multiplying this quantity by the NH.)

2000 2005 2010 2015

Year

500

10

5

0

0.05

0

Total 34WA (

0

106 nmi2) (a) Total 64WA(

106 nmi2) Ratio

(b)

(c)

mean=173.914106 nmi2

sd=141.244106 nmi2

mean=3.157106 nmi2

sd=2.974106 nmi2

mean=0.017

sd=0.008

y = 4.338 – 0.002x

r = –0.847, r 2 = 0.717

se = 0.006, cl > 98%

y

Figure 3. Yearly variation of the (a) total 34WA, (b) total 64WA, and (c) ratio 

 (total 64WA/total 34WA) for the interval 2004–2013.
21

 Figure 4 plots the yearly variation of several climate-related factors for the interval 2004 –2013, 

including (a) <ONI>, (b) <SOI>, (c) <AMO>, (d) <MLCO2>, and (e) <GLOTI>. For <ONI>, 

large positive values tend to be associated with the occurrences of warm (El Niño-like) events and 

large negative values tend to be associated with the occurrences of cool (La Niña-like) events. For 

<SOI>, the opposite is true, with large positive values tending to be associated with the occurrences 

of cool (La Niña-like) events and large negative values tending to be associated with the occurrences 

of warm (El Niño-like) events. Hence, the years 2004 –2006 and 2009 tend to be associated with 

warming in the Niño 3.4 region of the Pacific Ocean, while the years 2007–2008 and 2010–2011 

tend to be associated with cooling. The mean (and sd) values of <ONI> and <SOI> for the interval 

2004 –2013 measure –0.16 °C (0.41 °C) and 2.5 (6.4), respectively, with extremes of about 0.44 °C 

in 2004 and –0.73 °C in 2011 for <ONI> and –4.8 in 2004 and 13.3 in 2011 for <SOI>. For the first 

6 months of the year 2014, ONI has averaged about –0.3 °C, and for the first 7 months of the year 

2014, SOI has averaged about 0.9, both values indicative of neutral El Niño-Southern Oscillation 

conditions, although El Niño is strongly anticipated to occur during the Northern Hemisphere fall 

and early winter by the Climate Prediction Center and the International Research Institute for Climate and Society.7 (ONI and SOI are computed as anomalies relative to specific based periods.)

 For <AMO> and <GLOTI>, they both appear to be rather flat in terms of yearly value 

during the interval 2004 –2013, averaging about 0.199 °C (0.093 °C) and 0.583 °C (0.057 °C), respectively. The <AMO> is presently in the warm phase, having entered the warm phase about 1995 and 

being especially warm in 2010 (0.358 °C). The <GLOTI> has remained positive in value continuously since 1977. For the first 7 months of 2014, AMO has averaged about 0.023 °C and for the first 

6 months of 2014, GLOTI has averaged about 0.647 °C.

 For <MLCO2>, it has continuously risen in value every year since its first measurement in 

1959. During the interval 2004 –2013, it has risen from 377.49 ppm in 2004 to 396.48 ppm in 2013. 

The value for <MLCO2> is expected to be >398 ppm in 2014 and >400 ppm in 2015. (For the first 

7 months of 2014, MLCO2 has averaged about 399.78 ppm.)
22

1

0.5

0

–0.5

–1

15

10

5

0

–5

<ONI> <SOI> <AMO> <MLCO2> <GLOTI>

(a)

(b)

(c)

(d)

(e)

0.5

400

350

1.0

0.5

0

2000 2005 2010 2015

Year

mean=–0.16 °C

sd=0.41 °C

mean=2.5

sd=6.4

mean=0.199 °C

sd=0.093 °C

mean=0.583 °C

sd=0.057 °C

396.48 ppm

377.49 ppm

Warm

0

Figure 4. Yearly variation of total tropical cyclone wind areas (nmi2) for the interval 

 2004 –2013.
23

 For convenience, table 3 is included to provide the yearly values, means and sds for the tropical 

cyclone parameters NTC, NH, NSD, NHD, LIS(L34WR), <L34WR>, LIS(L34WA), <L34WA>, 

LIS(A34WA), <A34WA>, LIS(L64WR), <L64WR>, LIS(L64WA), <L64WA>, LIS(A64WA), and 

<A64WA> and for the climate-related parameters <ONI>, <SOI>, <AMO>, <MLCO2>, and 

<GLOTI> for the interval 2004 –2013. Also, table 4 is included to provide the yearly variations, 

means and sds for the 34- and 64-kt wind areas in nmi2 for the interval 2004 –2013 and table 5 

is included to provide the results of linear regression analysis based on comparisons of each of 

the tropical cyclone parameters, including total 34WA, total 64WA, and the ratio total 64WA/total 

34WA, against each of the climate-related factors.

Table 3. Yearly counts and averages of NTC, NH, 34- and 64-kt wind radii and wind 

 areas from HURDAT2 dataset, and selected climate-related factors for

 the interval 2004 –2013.

Year NTC NH NSD NHD

LIS

(L34WR) <L34WR>

LIS

(L34WA) <L34WA>

LIS

(A34WA) <A34WA>

2004 15 9 93.00 45.50 350 186 324,468 86,851 107,362 34,835

2005 28 15 131.50 49.50 375 148 236,601 57,219 83,037 23,998

2006 10 5 52.75 21.25 360 180 320,541 89,264 136,439 35,458

2007 15 6 37.75 12.25 300 130 151,975 39,216 64,686 20,490

2008 16 8 88.25 29.75 275 164 168,546 60,507 118,320 31,445

2009 9 3 30.00 12.00 275 134 162,067 41,113 82,425 22,800

2010 19 12 191.25 38.50 400 152 414,298 66,659 124,817 29,087

2011 19 7 89.75 26.00 330 140 185,197 48,958 92,686 26,028

2012 19 10 101.75 29.75 480 163 541,296 74,658 209,563 33,998

2013 14 2 42.25 3.25 300 116 153,388 36,594 96,245 1,963

 sum 164 77

mean 16.4 7.7 85.83 26.78 344.5 151.3 265,837.7 60,103.9 11,558.0 26,010.2

sd 5.4 4.0 49.38 15.04 63.7 22.3 132,308.2 19,157.0 40,706.2 9,961.3

Year

LIS

(L64WR) <L64WR>

LIS

(L64WA) <L64WA>

LIS

(A64WA) <A64WA> <ONI> <SOI> <AMO> <MLCO2> <GLOTI>

2004 100 54 21,795 7,898 9,262 3,985 0.44 –4.8 0.213 377.49 0.51

2005 90 46 21,049 6,251 11,588 3,135 0.08 –3.6 0.298 379.80 0.66

2006 100 61 20,577 8,203 6,584 3,184 0.13 –1.9 0.273 381.90 0.59

2007 60 41 7,069 3,475 4,132 2,158 –0.45 –0.6 0.148 383.76 0.62

2008 110 54 23,110 6,695 7,332 3,045 –0.69 10.2 0.146 385.59 0.49

2009 100 52 16,513 6,466 7,188 3,023 0.37 –0.2 0.047 387.37 0.59

2010 90 38 16,081 4,135 9,488 2,505 –0.33 9.8 0.358 389.85 0.66

2011 80 51 13,980 5,377 7,168 2,875 –0.73 13.3 0.110 391.63 0.54

2012 180 49 43,118 6,503 15,908 3,066 –0.06 –0.8 0.222 393.82 0.57

2013 40 35 2,985 2,003 2,469 1,509 –0.34 4.0 0.176 396.48 0.60

mean 95.0 48.1 18,627.7 5,700.6 8,111.9 2,848.5 –0.16 2.5 0.199 386.77 0.583

sd 36.6 8.1 10,803.4 1,966.2 3,777.8 666.0 0.41 6.4 0.093 6.20 0.057
24

Table 4. Yearly variation of total tropical cyclone wind areas (nmi2)

 for the interval 2004 –2013.

Year

Total 34WA 

(×106)

Total 64WA 

(×106)

Ratio

(total 64WA/

total 34WA)

2004 194.379 6.527 0.034

2005 353.443 9.311 0.026

2006 74.816 1.353 0.018

2007 46.410 0.634 0.014

2008 177.601 2.899 0.016

2009 24.624 0.435 0.018

2010 422.780 4.629 0.011

2011 177.537 2.093 0.012

2012 262.907 3.649 0.014

2013 4.644 0.039 0.008

mean 173.914 3.157 0.017

 sd 141.244 2.974 0.008

 From table 5, one finds that only three of the inferred regressions against <ONI> are considered to be of marginal statistical significance or better, with only one considered to be statistically 

important (cl >95%), ratio versus <ONI>. For comparisons against <SOI>, only one is considered 

to be statistically important, ratio versus <SOI>. For comparisons against <AMO>, eight of the 

inferred regressions against <AMO> are considered to be of marginal statistical significance or better, with four considered to be statistically important, including NH versus <AMO>, NSD versus 

<AMO>, LIS(L34WR) versus <AMO>, and total 34WA versus <AMO>. For comparisons against 

<MLCO2>, four of the inferred regressions are considered to be of marginal significance or better, 

with two considered to be statistically important, including <A64WA> versus <MLCO2> and ratio 

versus <MLCO2>. Lastly, for comparisons against <GLOTI>, only one inferred regression is considered to be of marginal statistical significance, <L64WR> versus <GLOTI>, with none considered 

to be statistically important.
25

Table 5. Summary of statistics based on comparison of tropical cyclone parameters 

 and specific climate-related factors.

Parameter

<ONI> <SOI>

a b rr2 se cl a b r r2 se cl

NTC 15.945 –2.881 –0.222 0.049 5.563 <90% 16.237 0.064 0.077 0.006 5.689 <90%

NH 7.753 0.334 0.035 0.001 4.241 <90% 7.798 –0.038 –0.061 0.004 4.234 <90%

NSD 83.576 –14.237 –0.119 0.014 52.003 <90% 80.134 2.241 0.291 0.084 50.116 <90%

NHD 28.092 8.338 0.230 0.053 15.528 <90% 27.539 –0.301 –0.128 0.016 15.822 <90%

LIS(L34WR) 349.455 31.359 0.204 0.042 66.100 <90% 349.794 –2.084 –0.210 0.044 66.018 <90%

<L34WR> 154.624 21.036 0.391 0.153 21.739 <90% 153.760 –0.968 –0.278 0.078 22.683 <90%

LIS(L34WA) 280,383.878 92,064.418 0.288 0.083 134,380.244 <90% 275,961.730 –3,985.839 –0.193 0.037 137,697.662 <90%

<L34WA> 63,227.236 19,767.951 0.427 0.183 18,369.956 <90% 62,461.825 –928.317 –0.310 0.096 19,315.851 <90%

LIS(A34WA) 112,937.770 8,732.724 0.089 0.008 43,004.727 <90% 112,124.011 –222.839 –0.035 0.001 43,148.945 <90%

<A34WA> 26,948.204 5,936.736 0.247 0.061 10,238.605 <90% 26,463.462 –178.450 –0.115 0.013 10,495.762 <90%

Total 34WA 171.613 –14.561 –0.043 0.002 149.675 <90% 164.786 3.594 0.163 0.027 147.809 <90%

LIS(L64WR) 98.674 23.255 0.263 0.069 37.442 <90% 97.608 –1.027 –0.180 0.032 38.179 <90%

<L64WR> 49.153 6.664 0.341 0.116 8.065 <90% 48.755 –0.258 –0.204 0.042 8.400 <90%

LIS(L64WA) 19,779.032 7,286.914 0.279 0.078 11,002.524 <90% 19,615.068 –388.728 –0.230 0.053 11,150.345 <90%

<L64WA> 6,099.417 2,524.160 0.532 0.283 1,766.264 >90% 5,983.000 –111.181 –0.362 0.131 1,943.926 <90%

LIS(A64WA) 8,547.747 2,758.526 0.302 0.091 3,819.372 <90% 8,444.899 –131.102 –0.222 0.049 3,906.788 <90%

<A64WA> 2,985.921 869.753 0.541 0.293 594.199 >90% 2,939.929 –35.996 –0.346 0.120 662.775 <90%

Total 64WA 3.502 2.182 0.304 0.092 3.005 <90% 3.488 –0.130 –0.280 0.079 3.027 <90%

Ratio 0.019 0.013 0.689 0.475 0.006 >95% 0.019 –0.001 –0.645 0.416 0.007 >95%

Parameter

<AMO> <MLCO2>

a b rr2 se cl a b r r2 se cl

NTC 10.879 27.728 0.481 0.231 5.004 <90% 39.603 –0.060 –0.069 0.005 5.697 <90%

NH 1.959 28.836 0.672 0.452 3.143 >95% 93.853 –0.223 –0.345 0.119 4.098 <90%

NSD 7.543 393.181 0.742 0.551 35.113 >98% 178.041 –0.238 –0.030 0.001 52.185 <90%

NHD 7.755 95.527 0.592 0.351 12.856 >90% 528.235 –1.297 –0.535 0.286 13.701 <90%

LIS(L34WR) 255.403 447.500 0.655 0.430 50.993 >95% –167.880 1.325 0.129 0.017 66.669 <90%

<L34WR> 132.156 96.153 0.403 0.162 21.623 <90% 947.661 –2.059 –0.573 0.329 19.334 >90%

LIS(L34WA) 91,754.726 874,349.441 0.616 0.380 110,527.347 >90% –520,377.387 2,032.777 0.095 0.009 139,695.169 <90%

<L34WA> 36,982.054 116,131.823 0.565 0.320 16,761.621 >90% 594,788.313 –1,382.439 –0.448 0.200 18,169.743 <90%

LIS(A34WA) 81,499.004 150,974.365 0.346 0.120 40,511.539 <90% –696,501.038 2,089.255 0.318 0.101 40,928.694 <90%

<A34WA> 20,083.159 29,769.164 0.279 0.078 10,147.039 <90% 331,146.093 –788.936 –0.491 0.241 9,202.648 <90%

Total 34WA –42.149 1,085.197 0.716 0.513 104.523 >98% 1,179.989 –2.601 –0.114 0.013 148.766 <90%

LIS(L64WR) 84.987 50.290 0.128 0.016 38.491 <90% 59.653 0.091 0.015 – 39.036 <90%

<L64WR> 51.296 –16.053 –0.185 0.034 8.432 <90% 298.328 –0.647 –0.496 0.246 7.496 <90%

LIS(L64WA) 13,453.581 25,987.538 0.224 0.050 11,166.760 <90% 60,165.789 –107.398 –0.062 0.004 11,437.033 <90%

<L64WA> 5,450.570 1,255.799 0.060 0.004 2,081.767 <90% 80,605.699 –193.669 –0.611 0.373 1,651.042 >90%

LIS(A64WA) 4,946.995 15,896.056 0.392 0.154 3,685.720 <90% 25,192.225 –44.162 –0.073 0.005 3,996.658 <90%

<A64WA> 2,730.907 590.624 0.083 0.007 704.014 <90% 30,353.645 –71.115 –0.662 0.439 529.032 >95%

Total 64WA –0.636 19.052 0.597 0.357 2.529 >90% 99.827 –0.250 –0.521 0.272 2.708 <90%
26

Table 5. Summary of statistics based on comparison of tropical cyclone parameters 

 and specific climate-related factors (Continued).

Parameter

<GLOTI>

a b rr2 se cl

NTC –1.281 30.328 0.323 0.105 5.398 <90%

NH –3.306 18.879 0.271 0.073 4.085 <90%

NSD –59.241 248.826 0.289 0.084 50.143 <90%

NHD 28.266 –2.558 –0.010 – 15.953 <90%

LIS(L34WR) 171.923 296.015 0.267 0.071 65.076 <90%

<L34WR> 247.561 –165.113 –0.425 0.181 21.380 <90%

LIS(L34WA) 120,788.856 248,797.332 0.108 0.012 139,515.333 <90%

<L34WA> 109,695.069 –85,062.040 –0.255 0.065 19,648.969 <90%

LIS(A34WA) 190,012.946 –134,571.091 –0.190 0.036 42,392.160 <90%

<A34WA> 60,302.374 –58,820.196 –0.339 0.115 9,941.056 <90%

Total 34WA –229.774 692.433 0.281 0.079 143.766 <90%

LIS(L64WR) 196.400 –173.928 –0.273 0.074 37.340 <90%

<L64WR> 95.807 –81.830 –0.580 0.337 6.987 >90%

LIS(L64WA) 47,590.671 –49,679.196 –0.264 0.070 11,052.931 <90%

<L64WA> 14,558.971 –15,194.461 –0.443 0.196 1,869.400 <90%

LIS(A64WA) 7,303.005 1,387.470 0.021 – 4,006.105 <90%

<A64WA> 5,887.444 –5,212.597 –0.449 0.202 631.254 <90%

Total 64WA –1.303 7.650 0.148 0.022 3.120 <90%

Ratio 0.035 –0.031 –0.230 0.053 0.008 <90%

 Figure 5 displays the scatterplots of ratio versus (a) <ONI>, (b) <SOI>, and (c) <MLCO2>. 

From figure 5(a) and (b), one finds that when <ONI> (<SOI>) is of positive (negative) value, the 

ratio of total 64-kt wind area to total 34-kt wind area usually is higher (lower) than when <ONI> 

(<SOI>) is of negative (positive) value. Thus, if an El Niño (warm event) should occur in the Northern Hemisphere fall-early winter during the year 2014, one expects the <ONI> (<SOI>) to be of 

positive (negative) value and the ratio to be larger (smaller) than about 0.016. While an El Niño 

was highly anticipated by the Climate Prediction Center and the International Research Institute 

for Climate and Society in earlier forecasts (May 8, 2014, June 5, 2014, and July 10, 2014), the most 

recent forecast (August 7, 2014)7 has reduced the chance of an El Niño from 80% to 65%. If El Niño 

neutral conditions continue to prevail, this suggests a lower ratio of total 64-kt wind area to total 

34-kt wind area for the year 2014 (≤0.016). Of the three correlations shown in figure 5, the strongest (r = –0.85) is the one against <MLCO2>. Since the yearly atmospheric concentration of CO2

continues to grow, based on <MLCO2>, one expects that the ratio of total 64-kt wind area to total 

34-kt wind area for the year 2014 will be of lower value (≤0.012). (Again, through June 2014, ONI 

averages about –0.3 °C, while through July 2014, SOI averages about 0.9 and MLCO2 averages about 

399.78 ppm.)
27

y

y

y

Cool Warm

<ONI>

<SOI>

<MLCO2>

Ratio

r=0.69

r=–0.64

r=–0.85

0.05

0

0

0

Ratio

0.05

 –1 –0.5 0 0.5 1

–10 –5 0 5 10 15 

375 380 385 390 395 400

(a)

(b)Ratio

0.05

(c)

Figure 5. Scatterplots of ratio versus (a) <ONI>, (b) <SOI>, and (c) <MLCO2>.
28

y

y

y

NH

(a)NSD

(b)

r=0.72

r=0.66

r=0.74

Sandy

r=0.67

20

15

10

5

0

200

150

100

50

0

500

450

400

350

300

250

LIS(L34WR)

Total 

34WA

(c)

(d)

500

0

0 0.1 0.2 0.3 0.4 0.5

<AMO>

y

Figure 6. Scatterplots of (a) NH, (b) NSD, (c) LIS(L34WR), and (d) total 34WA 

 versus <AMO>.

 Figure 6 shows the scatterplots of (a) NH, (b) NSD, (c) LIS(L34WR), and (d) total 34WA 

versus <AMO>. From the plots, one finds that warmer <AMO> tends to be associated with larger 

NH, NSD, LIS(L34WR), and total 34WA than cooler <AMO>. Of the four scatterplots, the one 

having the strongest correlation is the one between total 34WA and <AMO> (r = 0.72). Hence, 

dependent upon the value for <AMO> in the year 2014, yearly values for NH, NSD, LIS(L34WR), 

and total 34WA will be either above (below) their mean values if <AMO> ≥ 0.195 oC (or <0.195 oC). 

Presently, lower values for these parameters are expected. (Again, through July 2014, AMO averages 

about 0.023 oC.)
29

 Figure 7 depicts the scatterplot of <A64WA> versus <MLCO2>. Assuming <MLCO2> 

= 398.48 ppm in 2014, one estimates <A64WA> for the 2014 hurricane season to be ≤2,545 nmi2.

 As noted above, through July 2014, MLCO2 is averaging about 399.98 ppm. Monthly values 

are expected to slightly decrease during the last 5 months of the year, due to seasonal effects, thereby 

causing the yearly <MLCO2> to be slightly smaller than 399.98 ppm. If the last 5 months of the 

year average higher (lower) than 396.38 ppm, then <MLCO2> for 2014 will be greater (smaller) than 

398.48 ppm, suggesting that the estimated value for <A64WA> will be slightly lower (higher). <A64WA>

<MLCO2>

4,000

3,000

2,000

1,000

0

r=–0.66

y

375 380 385 390 395 400

Figure 7. Scatterplot of <A64WA> versus <MLCO2>.
30

3. SUMMARY

 The HURDAT2 database now includes estimates of the 34-, 50-, and 64-kt wind radii (by 

quadrant), where the 34- and 64-kt wind radii, respectively, show the extent of the tropical storm 

and hurricane-force winds from the center of circulation of the tropical cyclone. Knowledge of these 

radii then allows for the estimation of the actual sizes of the individual tropical cyclones. Unfortunately, the HURDAT2 database only covers the very brief 10-year interval 2004–2013.

 During the interval 2004 –2013, some 164 tropical cyclones are observed to have formed in 

the North Atlantic basin, of which 77 became hurricanes. This study has examined the 34- and 64-kt 

wind radii associated with these tropical cyclones to determine the sizes of their 34- and 64-kt wind 

fields. Also, this study has examined the distributions of the 34- and 64-kt wind radii and areas and 

examined possible trends in the radii and areas, especially in comparison against selected climaterelated factors.

 Interesting is that hurricane Sandy (2012) stands out as being the largest individual storm 

that occurred in the North Atlantic basin during this timeframe, both in terms of its 34- and 64-kt 

wind radii and wind areas, having maximum 34- and 64-kt wind radii, maximum wind areas and 

average wind areas each more than 2 standard deviations larger than the corresponding means. Also, 

in terms of the largest yearly total 34-kt wind area (i.e., the sum of all individual storm wind areas 

during the year), the year 2010 stands out as being the largest (about 423 × 106 nmi2, compared to the 

mean of about 174 × 106 nmi2), surpassing the year 2005 (35 × 106 nmi2) that had the largest number 

of individual storms (28 tropical cyclones, with 15 becoming hurricanes), although in terms of the 

largest yearly total 64-kt wind area, the year 2005 stands out as being the largest (about 9 × 106 nmi2, 

compared to the mean of about 3 × 106 nmi2). Additionally, the ratio of total 64-kt wind area to total 

34-kt wind area has decreased over time, from 0.034 in 2004 to 0.008 in 2013.

 Regarding the distributions of the 34- and 64-kt wind radii and areas, the following was 

found:

 (1) For the 164 tropical cyclones during the interval 2004 –2013, the largest single grouping for 

L34WR is L34WR = 50–99 nmi (50/164 = 30%), with 135 of the 164 tropical cyclones (82%) having 

L34WR <300 nmi.

 (2) The two largest tropical cyclones in terms of L34WR are Igor (2010) and Sandy (2012), 

having the largest 34-kt wind radii of 400 and 480 nmi, respectively.

 (3) The largest single grouping for L34WA is L34WA <50 × 103 nmi2, accounting for 99 of the 

164 tropical cyclones (60%).

 (4) The two largest tropical cyclones in terms of L34WA are Igor (2010) and Sandy (2012), 

having the largest 34-kt wind area of about 414 × 103 and 541 × 103 nmi2, respectively.
31

 (5) The largest single grouping for A34WA is A34WA <25 × 103 nmi2, accounting for 102 of 

the 164 tropical cyclones (62%).

 (6) The two largest tropical cyclones in terms of A34WA are Florence (2006) and Sandy 

(2012), having the largest average 34-kt wind area of about 136 × 103 and 210 × 103 nmi2, respectively.

 (7) For the 77 hurricanes during the interval 2004 –2013, the largest single grouping for 

L64WR is L64WR = 25– 49 nmi (26/77 = 34%), with 72 of 77 (94%) having L64WR <100 nmi.

 (8) The largest storm in terms of L64WR is hurricane Sandy (2012), having the largest 64-kt 

wind radius of 180 nmi.

 (9) The largest single grouping for L64WA is L64WA <5 × 103 nmi2, accounting for 51 of the 

77 hurricanes (66%).

 (10) The largest storm in terms of L64WA is hurricane Sandy (2012), having the largest 64-kt 

wind area of about 43 × 103 nmi2.

 (11) The largest single grouping for A64WA is A64WA <2.5 × 103 nmi2, accounting for 48 of 

the 77 hurricanes (62%).

 (12) The two largest hurricanes in terms of A64WA are hurricanes Wilma (2005) and Sandy 

(2012), having the largest average 64-kt wind area of about 12 × 103 and 16 × 103 nmi2, respectively.

 Regarding comparisons against selected climate-related factors, the following was found:

 (1) The ratio of total yearly 64-kt wind area to total yearly 34-kt wind area appears to possibly be related to the phasing of the El Niño-Southern Oscillation, as described by <ONI> (r = 0.69; 

cl >95%) and/or <SOI> (r = 0.64; cl >95%), and especially <MLCO2> (r = –0.85; cl >95%).

 (2) NH, NSD, LIS(L34WR), and total 34WA all appear to be related to <AMO> (r ≥0.66; 

cl >95%).

 (3) <A64WA> appears to be related to <MLCO2> (r = –0.66; cl >95%).
32
33

APPENDIX

 The wind fields associated with tropical cyclones are rarely symmetrical. Usually, one quadrant of the tropical cyclone has the more extensive wind field. This is readily seen in the HURDAT2 

time measurements for Alex, the first tropical cyclone for the 2004 hurricane season, as shown in 

table 6. Clearly, the FSD for Alex occurred on August 1 at 1800 UT when its 1-min sustained PWS 

attained 35 kt and the storm was designated TS. Its onset location and LP at FSD measured 31.6° 

N. and 79.2° W. and 1,009 mb, respectively. At onset the 34-kt winds extended outwards from its 

center of circulation some 50 nmi in the SE and SW quadrants. Since the area of the wind field for 

each quadrant is computed as π/4 times the radius squared, the 34-kt wind area at FSD is computed 

to be π/4 times (02 + 502 + 502 + 02) nmi2, which equals 3,927 nmi2 (A34WA). The largest 34-kt wind 

area occurred on August 5 at 1200 UT measuring 150,816 nmi2 (= π/4(802 + 3002 + 3002 + 752)). The 

sum of the 20 individual time measurements of 34-kt wind areas equals 1,088,601 nmi2, thus yielding the average 34-kt wind area per time measurement as 54,430 nmi2 (= 1,088,601/20 nmi2/20). 

(The largest 34-kt wind area tropical cyclone for the year 2004, however, was Karl, which occurred 

September 16–24, 2004. It is classified as MH and has L34WR = 350 nmi, L34WA = 324,468 nmi2, 

and A34WA = 107,362 nmi2; see tables 1 and 3.)

 The total 34-kt wind area for the year is simply the sum of all the individual 34-kt wind areas 

for the tropical cyclones occurring during the year. Hence, the total 34-kt wind area for a hurricane 

season is equal to the average wind area per tropical cyclone per time measurement (<A34WA>) 

times the number of tropical cyclones (NTC) per year times the number of time measurements 

(= 4 × NSD). For the 2004 hurricane season, the total 34-kt wind area is computed to be 194.379 × 106

nmi2 (= 34,835 nmi2 per tropical cyclone × 15 tropical cyclones × 4 time measurements per day × 93.00 

storm days).

 For the 64-kt wind area, Alex attained hurricane force winds on August 3 at 0600 UT, marking its first hurricane day (FHD). At FHD, Alex had 64WA = 942 nmi2 (= π/4(202 + 202 + 202 + 02)). 

Its largest 64-kt wind area occurred on August 5 at 0000 UT through August 5 at 1200 UT, measuring 3,691 nmi2. The sum of the 13 individual time measurements of 64-kt wind areas equals 

35,458 nmi2, thus yielding the average 64-kt wind area per time measurement as 2,728 nmi2. (The 

largest 64-kt wind area hurricane for the year 2004 was Ivan, which occurred September 3–23, 2004, 

and is classified as MH and has L64WR = 100 nmi, L64WA = 21,795 nmi2, and A64WA = 9,262 nmi2.)

 The total 64-kt wind area for the year is simply the sum of all the individual 64-kt wind areas 

occurring during the year. Hence, the total 64-kt wind area for a hurricane season is equal to the 

average wind area per hurricane per time measurement (<A64WA>) times the number of hurricanes 

(NH) per year times the number of time measurements (= 4 × NHD). For the 2004 hurricane season, 

the total 64-kt wind area is computed to be 6.527 × 106 nmi2 (=3,985 nmi2 per hurricane × 9 hurricanes × 4 time measurements per day × 45.50 hurricane days).

 Inspection of table 6 shows that Alex became a major hurricane on August 5 at 0000 UT 

(FMHD) and continued as an MH through August 5 at 1200 UT (LMHD).
34

Wind Radii (nmi)

34 kt 50 kt 64 kt

Date UT Class

Lat.

(° N.)

Long.

(° W.) PWS LP NE SE SW NW NE SE SW NW NE SE SW NW 

07/31/2004 1800 TD 30.3 78.3 25 1,010 – – – ––––––––– 08/01/2004 0000 TD 31.0 78.8 25 1,009 – – – ––––––––– 08/01/2004 0600 TD 31.5 79.0 25 1,009 – – – ––––––––– 08/01/2004 1200 TD 31.6 79.1 30 1,009 – – – ––––––––– 08/01/2004 1800 TS 31.6 79.2 35 1,009 – 50 50 – – – – – – – – – 

08/02/2004 0000 TS 31.5 79.3 35 1,007 – 50 50 – – – –––––– 08/02/2004 0600 TS 31.4 79.4 40 1,005 60 90 90 – – – –––––– 

08/02/2004 1200 TS 31.3 79.0 50 992 75 90 60 20 30 30 –––––– 

08/02/2004 1800 TS 31.8 78.7 50 993 75 90 50 30 30 30 20 20 – – – – 08/03/2004 0000 TS 32.4 78.2 60 987 75 90 50 30 30 30 20 20 – – – – 08/03/2004 0600 HU 33.0 77.4 70 983 75 90 50 40 30 30 30 20 20 20 20 – 08/03/2004 1200 HU 34.2 76.4 85 974 75 90 50 40 30 50 30 20 20 20 20 – 08/03/2004 1800 HU 35.3 75.2 85 972 90 90 75 50 60 50 30 30 30 30 20 15 08/04/2004 0000 HU 36.0 73.7 80 974 80 100 75 50 40 50 40 20 15 40 30 15 08/04/2004 0600 HU 36.8 72.1 80 973 60 120 75 75 40 75 50 50 20 50 30 15 08/04/2004 1200 HU 37.3 70.2 85 973 60 120 75 75 40 75 50 50 20 50 30 15 08/04/2004 1800 HU 37.8 68.3 95 965 90 150 125 75 50 75 50 50 25 50 25 15 08/05/2004 0000 HU 38.5 66.0 105 957 80 150 125 75 50 80 60 50 30 50 30 20 08/05/2004 0600 HU 39.5 63.1 105 957 80 225 200 75 50 80 60 50 30 50 30 20 08/05/2004 1200 HU 40.8 59.6 100 962 80 300 300 75 50 80 60 50 30 50 30 20 08/05/2004 1800 HU 42.7 55.0 90 970 75 300 300 75 50 75 50 30 25 50 25 – 08/06/2004 0000 HU 44.5 49.3 75 978 75 300 300 75 50 75 50 30 25 50 25 – 08/06/2004 0600 HU 46.1 44.2 65 984 75 300 300 75 50 75 50 30 25 50 25 – 08/06/2004 1200 TS 47.0 37.5 50 987 75 300 300 75 50 75 50 30 – – – – 08/06/2004 1800 EX 47.4 32.7 30 992 –––––––––––– Mean 

Notes: TD = tropical depression TS = tropical storm HU = hurricane EX = extratropical

Table 6. HURDAT2 data for Alex during the 2004 hurricane season, with comments.
35

REFERENCES

1. Landsea, C.; Franklin, J.; and Beven, J.: The Revised Atlantic Hurricane Database (HURDAT2), 

National Hurricane Center, <http://www.nhc.noaa.gov/data/hurdat/hurdat2-format-atlantic.pdf>,

April 2014.

2. National Hurricane Center, <http://www.nhc.noaa.gov/data/hurdat/hurdat2-1851-2013-052714.

txt>, July 2014.

3. Wilson, R.M.: “Statistical Aspects of Tropical Cyclone Activity in the North Atlantic Basin, 

1945–2010,” NASA/TP—2012–217465, Marshall Space Flight Center, Huntsville, AL, 272 pp., 

August 2012.>

4. Wilson, R.M.: “Statistical Aspects of North Atlantic Basin Tropical Cyclones during the Weather 

Satellite Era, 1960–2013: Part 1,” NASA/TP—2014–218196, Marshall Space Flight Center, 

Huntsville, AL, 82 pp., July 2014.

5. Wilson, R.M.: “Statistical Aspects of North Atlantic Basin Tropical Cyclones during the Weather 

Satellite Era, 1960–2013: Part 2,” NASA/TP—2014–218198, Marshall Space Flight Center, 

Huntsville, AL, 90 pp., July 2014.

6. Wilson, R.M.: “On the Relationship Between the Length of Season and Tropical Cyclone Activity in the North Atlantic Basin During the Weather Satellite Era, 1960–2013,” NASA/TP—2014–

218199, Marshall Space Flight Center, Huntsville, AL, 28 pp., August 2014.

7. National Centers for Environmental Prediction, <http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf>, August 2014. 
36

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On the Sizes of the North Atlantic Basin Tropical Cyclones

Based on 34- and 64-kt Wind Radii Data, 2004 –2013

Robert M. Wilson

George C. Marshall Space Flight Center

Huntsville, AL 35812

National Aeronautics and Space Administration

Washington, DC 20546–0001

Unclassified-Unlimited

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Availability: NASA STI Information Desk (757–864–9658)

Prepared by the Science and Exploration Research Office, Science and Mission Systems Office

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Technical Publication

NASA/TP—2014–218200

tropical cyclones, size distributions, North Atlantic basin, climate

01–09–2014

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NASA

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At end of the 2012 hurricane season the National Hurricane Center retired the original HURDAT dataset and replaced it with the newer version HURDAT2, 

which reformatted the original data and included additional information, in particular, estimates of the 34-, 50, and 64-kt wind radii for the interval 2004 –2013. 

During the brief 10-year interval, some 164 tropical cyclones are noted to have formed in the North Atlantic basin, with 77 becoming hurricanes. Hurricane 

Sandy (2012) stands out as being the largest individual storm that occurred in the North Atlantic basin during the 2004 –2013 timeframe, both in terms of its 

34- and 64-kt wind radii and wind areas, having maximum 34- and 64-kt wind radii, maximum wind areas, and average wind areas each more than 2 standard 

deviations larger than the corresponding means. In terms of the largest yearly total 34-kt wind area (i.e., the sum of all individual storm 34-kt wind areas during the year), the year 2010 stands out as being the largest (about 423 × 106 nmi2, compared to the mean of about 174 × 106 nmi2), surpassing the year 2005 

(353 × 106 nmi2) that had the largest number of individual storms (28). However, in terms of the largest yearly total 64-kt wind area, the year 2005 was the 

largest (about 9 × 106 nmi2, compared to the mean of about 3 × 106 nmi2). Interesting is that the ratio of total 64-kt wind area to total 34-kt wind area has 

decreased over time, from 0.034 in 2004 to 0.008 in 2013.

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