UDC 551.515.23(261)"1972"
Atlantic Hurricane Season of 1972
R. H. SIMPSON and PAUL J. HEBERT-National Hurricane Center,
National Weather Service, NOAA, Miami, Fla.
ABSTRACT-A general overview of the 1972 hurricane
season in the North Atlantic is presented together with
detailed accounts of all named tropical cyclones.
1. GENERAL SUMMARY
The 1972 hurricane season was notable for a t least three
reasons. First, fewer tropical storms and hurricanes formed
in the Atlantic than in any season since 1930, despite the
fact that essentially the same number of hurricane seed-
lings were observed as in 1971 when above-normal storm
activity occurred. Only two tropical cyclones occurred in
1930 and only three in 1929. Secondly, in 1972 as in 1971,
most of the tropical cyclones developed in temperate
latitudes, Agnes being the only one to form in the Tropics.
There were no severe hurricanes, and only Betty had
sustained winds of more than minimal hurricane force.
Finally, 1972 will be remembered as the year of record
hurricane damage. Hurricane Agnes, following a 700-mi
overland excursion after its landfall in northwest Florida,
was responsible for the most damaging floods ever recorded
when excessive rains fell in Pennsylvania, Maryland, and
Virginia. Property damage in the United States attributed
to Agnes is estimated to be near $3.1 billion. However, less
than 120 lives were lost. Major damage occurred in
western Cuba due to torrential rains, and seven lives were
lost there.
In addition to the tropical cyclone activity, further
experience was gained during 1972 with small, circular,
hybrid cyclones, referred to in earlier articles as neuter-
canes (Simpson and Hope 1972, Simpson and Pelissier
1971). Aircraft reconnaissance provided details of circu-
lation, and other sources of information shed new light on
the structure and unstable energetics of these interesting,
elusive, but potentially dangerous marine storms. Some of
this information will be presented below.
Of more than casual interest are the circumstances that
led to such an inactive hurricane season. In 1971, with
about the same number of seedlings as in 1972 (Frank
1973), three times as many tropical storms formed (fig. 1).
One reason for the lack of storm activity may have been
the below-normal sea-surface temperatures in the region
from the Lesser Antilles to Africa during much of the
hurricane season. A typical example is given in figure 2.
During this period the sea-surface temperatures in the
extreme eastern Pacific were well above normal and
tropical cyclones occurred there in greater numbers, larger
sizes, and greater strength than normal. Figure 3 shows
the temperature anomalies for the figure 2 temperatures.
A second reason for inactivity was the persistently large
vertical shear of the horizontal wind in the customary
cyclogenetical areas of the Tropics during most of the
season, as shown in figure 4. I n contrast, however, the
shear was appreciably smaller and sea-surface tempera-
tures were more favorable for development in temperate
latitudes of the Atlantic (Gray 1967). The unusual shear
resulted mainly from strong west winds in the upper
troposphere, which maintained a high percentage of
steadiness.' Under these conditions, convective releases of
latent heat in tropical disturbances do not remain suffi-
ciently pooled in deep tropospheric columns to cause
falling surface pressure and systematic development of
mass circulation. Finally, the intertropical convergence
zone and its attendant vorticities did not migrate north-
ward +th the equatorial trough in the eastern Atlantic or
western Caribbean Sea as the season progressed. The
reasons for this are not clearly apparent from information
available, but some evidence suggests that this may have
been a response to circulation anomalies in the Southern
Hemisphere.
With the exception of Agnes, which developed from a
disturbance that moved eastward from the Yucatan
Peninsula on June 14, all of the 1972 tropical cyclones
developed in temperate latitudes from disturbances
located within br adjacent to a baroclinic circulation
environment. While three of the four named storms
reached hurricane intensity, they accounted for a total
of only 8 hurricane days. Except for 1970, which had only
7 hurricane days, this year had the lowest total in the last
three decades. The lowest pressure observed in any storm
during the season was 976 mb. I n storms other than
Agnes, four lives were lost and damage to property was
$1.78 million. Figure 5 shows the tropical cyclones of 1972,
and table 1 summarizes the statistics of these four storms.
Bulletins were issued on three small, circular hybrid
cyclones (neutercanes) and one larger subtropical cyclone.
These were identified in 1972 by names from the phonetic
alphabet for the f i s t time. Figure 6 shows the tracks of
these cyclones. Alfa, having its origin in a large-scale
(PalmBn type) cold Low, initially moved northeastward
off the Florida coast to near Hatteras, N.C., where its
progress was blocked by a developing high-pressure ridge.
As this cold Low system was displaced southwestward
by the ridge, an intense, small, low-pressure center de-
veloped rapidly, and, late on May 25, it attained winds of
gale force. The extremely small center moved inland just
1 During the annual NOAA hurricane review conIcre,nce in Novcmbcr 1972, R. C .
Gentry reported a steadiness of 2Wmb winds over the Caribbean of 85-90 percent in
August and September.
April 1973 / 323
24 1 I I I I I I I I I
1900
n
0 1920 i! I 1950 1960 19
YEARS
FIGURE 1.-Frequency of North Atlantic hurricanes (shaded) and tropical storms and hurricanes (unshaded) for the period 1900-72 and of
seedlings for the period 1968-72 (Frank 1973).
_, ..,. - -
P
FIQURE a.--Sea-surface temperature field (OF) for the North Atlantic and eastern North Pacific for the period Aug. 8-18, 1972. The 80F
isotherm indicates the Palmen threshold for hurricane development (Palmen 1948).
south of Brunswick, Ga., late on the 27th with sustained
winds of 45 k t affecting a very small area. The micro-
barograph trace for Alfa from Fernandina Beach, Fla.,
characteristic of a tropical storm, is presented in figure 7.
Bravo developed on August 22 in a region of frontolysis
as a very small cyclone, 3040 mi in diameter. It moved
slowly eastward, grew in size and strength, gradually
acquired the structure of a tropical cyclone, and later
became hurricane Betty. The reconnaissance of this system
on August 25 showed some progress in acquiring a typical
tropical structure. On this day, the ATS 3 satellite picture
(fig. 8) showed not only the expanding well-organized
circulation of Bravo, but also a secondary small neutercane
to the west that after less than a day of existence failed
to develop and disappeared.
Charlie, in contrast to the growth pattern of Bravo,
formed on September 19 as a very small, circular cyclone
moving initially northward, then rapidly evolved into a
near-record extratropical cyclone with minimum pressure
of 946 mb.
Delta developed in the mid-Atlantic from a cold Low,
meandered southwestward and southward from the 35 th
to 30th parallel, then eastward, gradually losing its
identity after 5 days.
324 I Vol. 101, No. 4 / Monthly Weather Review
FIGURE 3.-Sea-surface temperature anomalies for figure 2, based on an objective analysis (Jarvinen 1973) and monthly normals (1941-71)
from the Scripps Institution of Oceanography, La Jolla, Calif.
FIGURE 4.-NHC tropospheric mean wind shear field (60040 200-mb upper mean minus the 1000-to 600-mb lower mean) for the period
Aug. 15-Sept. 15, 1972.
All the midget cyclones were initially circular, and all
formed between the 30th and 40th parallels with different
metamorphosis of structure.
2. INDIVIDUAL STORMS
Hurricane Agnes, June 14-22
The life history of Agnes is most appropriately divided
into two parts-one, a June hurricane that developed,
strengthened, and moved to its landfall on the coast of
the Florida panhandle in close accord with climatological
-
expectancy, and the other, a dissipating tropical depres-
sion which, having moved inland, became rejuvenated
under the stimulus of a vigorous baroclinic environment.
The one unusual feature of Agnes in the Gulf of
Mexico-a circulation envelope 1,000 n.mi. in diameter,
making it one of the largest June hurricanes of record-
was maintained after the storm moved inland. The
enormous moisture supply and near-saturated conditions
in this large circulation were enhanced as the center
proceeded northward, making the difference between
what might have been a localized flooding condition and
the record-breaking floods that did occur.
April 1973 Simpson and Hebert 1 325
FIGURE 5.-Tracks of Atlantic tropical storms and hurricanes of 1972.
TABLE 1.-Summary of North Atlantic tropical
cyclone statistics, 1972
Maximum Lowest us.
wind (kt) (mb) ($millions) Nnmo Date sustained pressure damage Deaths
1. Agnes (H) June 14-22 75 977 3,097 U.S. 117
2. Betty (H) Aug. 22-Sept. 1 90 976
3. Carrie (T) Aug. 29-Sept. 5 60 992 1.78 U.S. 4
Cuba 7
4. Daw11 (H) Sept. 4-14 70 997
Hemispheric circulations and anomaly patterns during
June prior to Agnes progressed in a manner favoring
hurricane development in the western Caribbean Sea
(Hebert and Miller 1969). On the synoptic scale, banded
convection f i s t appeared over the northwestern Carib-
326 / Vol. 101, No. 4 / Monthly Weather Review
bean Sea on June 11. A fairly strong baroclinic zone was
established between the Yucatan and Florida peninsulas
during the next 3 days as a weakening polar front and
its associated upper trough moved to southern Florida
and the western Bahamas. As the trough moved eastward,
tropospheric wind shears over northern Yucatan and
adjacent waters decreased, and the convective warming
process led to localized pressure falls near Cozumel on the
14th. The strong depression that resulted moved east-
ward from the Yucatan peninsula on the 15th. Although
military reconnaissance aircraft reported squalls of 40 kt
and higher as early as the 14th, the ATS 3 film loops and
reconnaissance reports on the 15th revealed only a poorly
organized central area with no sustained winds of tropical
storm strength. However, the depression reached tropical
FIGURE 6.-Tracks of Atlantic subtropical cyclones of 1972.
storm strength while drifting eastward that night and was
named early on the 16th.
Satellite pictures on the 16th revealed an extension of
the disturbed weather area from the Agnes center east-
ward to Puerto Rico and northeastward more than 2,000
n.mi. into the Atlantic, associated with the lingering
shear line and trough extending to the northeast of the
storm center. With the growth of Agnes, a second orga-
nized convective system evolved within this extensive
belt of disturbed weather, initially about 450 n.mi.
south-southwest of Bermuda, and persisted as a strong
depression throughout most of the life cycle of Agnes.
Figure 9 is an ATS 3 picture made on the 17th showing
two well-defined circulation systems. The depression
developed gale-force winds in squalls, posing a grave
threat and causing considerable damage to some boats
involved in the biennial Newport to Bermuda Yacht Race.
On a larger scale, this depression served to enhance the
influx of moisture and saturated air into Agnes as the lat-
ter proceeded northward over land. As late as the 23d,
this extensive, persistent band of disturbed weather east
of Agnes spawned still another depression 1,000 n.mi.
east of Bermuda.
Agnes became a hurricane on the 18th with sustained
April 1973 / Simpson and Hebert / 327
surface winds of 75 kt reported by NOAA reconnaissance
aircraft late that day. The central pressure decreased to
978 mb in the Gulf of Mexico early on the 19th. An
unfavorable environment led to weakening before Agnes
made its initial landfall in early afternoon near Cape San
Blas, Fla. Military reconnaissancqeports indicated maxi-
mum sustained winds of 65 kt prior to landfall, but fur-
ther weakening occurred; the highest wind reported by a
land station was a gust to 48 kt at Apalachicola, Fla.
12 15 18 21 00
TIME E ST
FIGURE 7.-Fernandina Beach, Fla., barogram on May 27, 1972, as
subtropical cyclone Alfa moved inland just to the north.
Despite this, little doubt exists that sustained winds of
hurricane force were present offshore (not only recon-
naissance measurement but also storm tides of 6.4 ft above
normal observed at Apalachicola and 7.0 ft at Cedar Key,
Fla.) .
Agnes was reduced to depression strength as it turned
northeastward into Georgia on the 20th. However, as the
ridge of high pressure over the western Atlantic continued
to build, a major extratropical trough approached the
weakening depression. Agnes circulation experienced re-
newed acceleration as a result of a release of fresh energy
from baroclinic sources, and the central pressure again fell.
Early on the 21st, a secondary Low center developed west
of the old Agnes depression center. The two Lows then
moved in tandem. This complex syst,em again reached
tropical storm strength late on the 21st while the centers
were still over land in North Carolina. The secondary Low
center remained inland and ultimately became dominant,
but not before the Agnes center moved offshore near Nor-
folk, Va., that evening t o almost regain its previous
strength. Military reconnaissance flights reported maxi-
mum sustained winds of 60 kt on the 22d, and the lowest
central pressure recorded in Agnes (977 mb) was observed
just off the New Jersey coast. The two centers turned
northward and westward under the steering influence of a
cold Low that had developed over the lower Ohio valley.
The seaward center crossed the western tip of Long Island,
I
1
,
FIGURE 8.-Enlargement of ATS 3 satellite photograph for 1301 GMT, Aug. 25, 1972, showing subtropical cyclone Bravo and a secondary
smaller system to the southwest.
328 / Vol. 101, No. 4 / Monthly Weather Review
FIQURE 9.-Blowup of ATS 3 satellite photograph for 1331 GMT, June 17, 1972, showing hurricane Agnes and a largc convective system t.0
the east. that spawned R. tropical depression on the 18t.h.
N.Y., on the afternoon of the 22d and was absorbed that
night over Connecticut int,o the circulation of the clomina.nt
secondary Low cent.er, which had moved to northeastern
Pennsylvania.
Satellite pictures gave evidence that t,he primary rain
shield associated with Agnes as it crossed t,he Florida pan-
handle was t,ransport<ed int,o t,he Atlant.ic early on the 21st.
The radar at Athens, Ga., observed a rapid decline of prc-
cipitafion late on t,he Wth, and less t>ha.n 4 in. of rain fell
in Georgia during the passage of Agnes. With the forrna-
tion of the secondary low center on the 21st, however,
rainfall inland began to increase in response to baroclinic
releases of energy. Six to 10 in. of rain fell over North
Carolina and New York and 10-14 in. fell over broad areas
of Virginia, Ma.ryland, and Pennsylvania.
It is difficult, if not impossible, to determine how much
of the rainfall might have occurred separately from the
baroclinic syst,em had Agnes not been located to t,he east.
As in the case of hurricane Diane of 1955, the already
saturated soil and the effect of the topography were also
factors in producing the (1evastat)ing floods. Regardless of
the energy sources and circulation dynamics that caused
the floods, however, this devastation could not have
occurred without the extreme importations of moisture to
the area by the depression that had been hurricane Agnes.
Thus, the damage due to river floods, far exc.eeding the
combined losses from Camille in 1969 and Betsy in 1965-
previously t,he t,im most destructive storms of history-
must be charged to Agnes, t,he greatmest, nnt'ural disaster
of all t.imes in terms of dollar losses.
The only deaths and significant. damage not produced by
river floods occurred in Florida as a result. of tidal flooding,
tornadocs, and windst.orms. Tides of 3-5 ft. above norme.1
caused some damage from Fort, Myers t,o the Tampa Bay
area with more extensive damage around Apalachicola
and Cedar Key wit,h t,he 6- to 7-ft t,ides. Windstorms
around Lake Okeechobee. late on the 18th accounted for
six of t.he nine deat.hs in Florida. A t,otal of 15 tornadoes
occurred in Florida on t.hc 18th and 19th wit,h two addi-
tional torna,does in Georgia on the 19th.
Table 2 gives t,he mct,eorological tlsta associated direct,ly
wit.h Agnes a1 t>hough some rainfall amounts are included
from South Carolina northward. Detailed information on
t,he rainfall and river stages elsewhere can be fonnd in
climatic dat:a publications of t,he National Climatic
Center at Asheville, N.C.
Forecasts and warnings issued while Agnes was in the
Gulf of Mexico were unusually acciirat,e. The vector dis-
placement error for 24-hr predictions averaged about 50
n.mi., less than half the long-term average. The 24-hr
landfall error for the Florida coast:line was less than 15
n.mi., and the time of landfall wBs within 2 hr. The hur-
April 1973 f Simpson and Hebert 1 329
TABLE 2.-Hurricane Agnes, meteorological da!a, June 14-82, 1972
Pressure (in.) - Wind (mi/hr)
Low Time Fastest Time Ousts Time (EST) mile (EST) (EST)
Date Station
Highest tide Time Storm (It above (EST) rainfall Dates normal) (in.)
Cuba
Cape San Antonio
Isle of Pines
Florida
Apalachicola WSO
Big Pine Key
Cedar Key
Crestview FAA
Daytona Beach WSO
Everglades
Flamingo
Fort Myers WSO
Jacksonville WSO
Kennedy SIC
Key West WSO
Lakeland WSO
Miami WSMO
Naples
Orlando WSO
Panama City
Panama City FAA
Pensacola NAS
Pensacola WSO
St. Petersburg FAA
Tallahassee WSO
Tampa WSO
Tyndall AFB (Panama City)
West Palm Beach WSO
Alabama
Dothan FAA
Mobile WSO
Georgia
Albany FAA
Augusta WSO
Brunswick FAA
Macon WSO
Savannah WSO
South Carolina
Beaufort MCAS
Charleston WSO
Columbia WSO
Florence FAA
Greer WSO
Myrtle Beach
North Carolina '
Cape Hatteras WSO
Elizabeth City FAA
Greensboro WSO
Raleigh WSFO
Rocky Mount FAA
Wilmington WSO
Virginia
Chesapeake L/V
Langley AFB
Norfolk WSO
Richmond WSO
See footnotes a t end of table.
19 29. 15 1512
18 SSE 32
19
19 NE 39
19 29. 68 1656 E 29
18 SSE 42
18 29. 65 1630 SE 25
19 E 39
19 SSE 52
18 29. 59 0310 SE 43
18 SE 33
18 ESE 25
18
19
19 29. 167 1600
19 29. 44 1355
19 29.45 1700
19 29.27 1709
19 29.59 0600
19 29. 11 1458
18
19 29.588 0353
ESE 30
NNE 35
NE 40
NNE 35
NNW 23
S 29
S 31
SE 27
NE 40
E 32
20 29.26 2200 N 29
19 29. 59 1745 N 22
20 29.30 0555
20 29.32 1800 E 24
20 29.47 1558
20 29.40 1010 E 33
20 29.38 1800 E 3 7
21 29. 31 0200 SE 29
21 29. 30 0400
21 29. 30 0300 E 2 4
21 29.24 0400 WNW 23
21 29. 38 0200 E 21
21 29.23 0700 WNW 29
21 29.13 1755 WNW 37
21 29.'11 1758 SSE 23
21 29. 30 0700 NW 26
.21 29. 25 0956 N 24
21 29. 18 1358 NNW 23
21 29.20 1055 SE 26*
21 29. 12 2300
21 29.11 1855 NNW 35
21 29, 10 2000 NW 42
21 29. 14 1658 NW 31
1140
0958
1812237
0735
0955
0637
0330
0519
1828
2228
2013
0200
0700
0737
1556
0850
1757
1812057
0655
1632
19/2157
1457
19/2010
19/1537
19/1349
19/1941
19/2255
1354
20/0200
1136
2158
0600
0804
1256
1555
20/1038
22/0055
22/0037
1905
15.32 13-18
16.76 13-18
E 55* 0612 6. 4 1512 3. 40 18-20
SE 50 1200 1 .2 8.43 17-20
55t 7. 0 2. 31
E 45
SSE 56
SE 53
SE 56
SSE 69#
E 52
SE 55
SE 36
E 41
NNE 44
0312
0700
0955
0637
0330
0144
1816
1523
1928
0200
1.7$ 0057 4. 37 18-19
7. 30 17-20
2. 0 1. 89
3. 0 5. 55 17-19
2. 8 5.36 18-20
6. 27
4. 59
0. 92
8.97 17-20
5.28 18-19
1. 2 1430 6. 19 17-20
3. 4 3. 10
NNE 49 0648 2. 58 18-19
N 43 1423 1. 7 0658 2. 34 18-20
S 48 1455 4. 1 2. 79
SSE 46 1817 7. 17 18-20
SE 43* 18/2048 5. 0 1115 3.47 18-19
5. 66 18-19
1. 97 17-19
NE 53 0655
E 46 1632
N 43 19/2157 3. 93 19-21
N 35 1452 1 .3 0330 1. 08 19
E 35 19/1957
E 52 19/1056
NE 35 19/1555
E 48 19/1340
4.54 19-21
3. 70 19-21
8. 55 ,19-21
3. 18 19-20
3. 95 19-21
ESE 46 19/1901 0 4. 11 19-21
E 40 19/2234 7. 0** 3. 10 19-21
E 32 19/2254 4. 19 19-21
WNW 44 1354 3. 61 19-21
N 29 20/2156 5.89 19-21
NW46 1350 1. 57 19-21
WNW 62 2155
ssw 35 1159
NNW 30 0747
WSW 31 22/1555
NNW 35 1555
SE 37 20/1004
0.43 20-21
5. 43 19-21 .
2.92 19-21
3.11 20-21
2. 52 19-21
NW 54 22/0058 0. 57 22-23
NW 54 22/0032 1. 2 1730 0. 33 20-23
NW 32 1858 3.28 20-23
330 1 Vol. 101, No. 4 1 Monthly Weather Review
TABLE 2.-Concluded
Station Date
~~
Pressure (in.) Wind (ml/hr) Highest
Low Time Fastest Time Ousts Time normal) (in.)
tide Time Storm
(ft above (EST) rainfall Dates
(EST) mile (EST) (EST)
District of Columbia
Andrews AFB, Md.
Dulles Int'l. AP, Va.
Washington Nat'l. AP
Maryland
Assateague
Baltimore WSO
Kentmorr Marina
Ocean City CGS
Patuxent NAS
Salisbury FAA
Delaware
Dover AFB
Indian River Inlet CGS
Wilmington WSO
New Jersey
Atlantic City WSO
Trenton WSO
N::w York
JFK Int'l. AP WSO
LaGuardia Fld. WSO
New York City WSO
Connecticut
Hartford WSO
New Haven FAA
Rhode Island
Providence WSO
21 29.26 1855 NNW 29
21 29. 29 1555 NNW 25
21 29.23 2215 XW 43
22 sw 20
22 29.24 0042 NW 37
22 NW 50
22 29. 09 0400 W 52
21 29. 12 2358 NNW 25
22 29.07 0256 NNW 37
22 29. 12 0355 NW 46
22 . .29. 12 0500 NW 46
22 29.12 0807 NW 35
22 29. 01 0900 WNW 31
22 29. 00 1300 SW 29
22 28.98 1451 WSW 32
22 28.98 1454 N E 4 1
22 28.99 1450 NE 36
22 29. 00 1730 S 29
22 29. 00 1712 SSW 29
22 29. 11 1559 S 26
2230
1855
2317
1100
0116
0224
0730
22/0158
0700
0928
1100
1055
1255
2018
1651
0848
0843
1931
2047
1928
NNW 46 0209
N 50 1853
NW49 2203
SW 50 0800
NW39 0155
NW 63 0212
NNW 43 22/0257
NW57 0708
NW67 0918
NW 50 1200
WNW 51 1133
w 49 1227
wsw 47 1712
wsw 44 1747
NE 55 0839
S 4 6 1923
SW 40 1945
S 38 1923
4. 0
3.0 1500
1. 5
2-3
2.9$ 1300
3.ltt 1107
3.2 1700
5. 57
13.65
8. 16
3. 14
6. 41
3. 53
3. 83
3. 17
4. 94
2. 12
2. 51
1. 25
1. 22
1. 86
1. 62
0. 26
21-22
20-23
20-23
21-23
20-23
21-23
21-23
20-23
21-23
22-23
21-23
21-23
21-23
21-23
22-23
22
*More than one occurrence
tEstlmated
tAbove mean sea level
UAltimeter settlng
**Above mean low water
ricane warning area issued a t 1800 EDT on June 18 from
St. Marks to the Panama City Beaches was one of the
smallest of record. The forecast height and area of the
maximum storm surge verified quite well. The weakening
of the hurricane as it approached the coast did not verify
hurricane force winds, but the recorded storm tides more
than justified the hurricane warnings. Gale warnings with
Agnes were issued elsewhere in Florida from Key West
to Dry Tortugas and along most gulf coastal sections. As
the center reintensified over North Carolina, gale warn-
ings were issued on the 21st from Savannah, Ga., to
Block Island, R.I.
Less well-forecast was the reintensification of the
storm center while over land, the increased intensity of
rainfall, and the attendant record-breaking floods. For
such a disaster, the loss of life was low.
Hurricane Betty, August 22-September 1
The first evidence of the disturbance that was to develop
into hurricance Betty appeared on the 21st in satellite
ttBattery Park
#Upper limit of recorder
Note: Portions of the data in this table were furnished courtesy of Environmental Data
Servlce, NOAA (DeAngelis and Hodge 1972).
pictures as a bright convective ,area within an old frontal
zone about 250 n.mi. north-northwest of Bermuda. On
the 22d, the SS Visurgis (OETK) reported southerly
winds of 35 k t at 1200 GMT, backing to southeaster'y 35
k t a t 1500 GMT. The disturbance was designated sib-
tropical cyclone Bravo on the 23d as ship reports suggested
winds had reached gale force, and a closed circulation
was more evident on ATS 3 pictures. The small size of
some of these systems was revealed by the SS Dordrecht
(PDRW), which reported 3-hourly isallobaric changes of
7-10 mb with a closed 1016 mb isobar of less than 125
n.mi. in diameter. During this development period, the
northern portion of a middle tropospheric trough off the
east coast moved eastward, leaving a cold Low east of
the Georgia coast. Data from weather ship Hotel (38ON,
71OW) suggested a second residual cold pool embedded in
a broad warm ridge over the area. This second cold pool
appeared to be the initiating mechanism for the develop-
ment.
Bravo continued eastward with little change in intensity
April 1973 / Simpson and Hebert / 331
during the next 24 hr. By the morning of the 25th, however, of 45-50 k t and a central pressure of 1002 mb as the
a deepening high-level trough to the northwest together center came abreast of Cape Hatteras.
with a building ridge to the south and east had enhanced no further devel- the outflow mechanism and convective processes. Military opment occurred as the vertical shear of the horizontal
reconnaissance reports indicated that a transformation to lvind increased with time. on september 1, the central
a warm core system was in Propess. The pressure pressure rose to 1007 mb and the strongest sustained winds
had dropped to below 1000 mb with sustained were only 40 kt. These minds reached a maximum more
winds of 45 to 50 kt. The ss Fort d'Orleans (Ii'*HW) than 100 n.mi. north of the center and were probably more
passed near the center just before daybreak, reporting the result of the increasing pressure gradient in the squalls to 55 k t and a minimum Pressure of 997 mb with anticyclone north of the storm than of the energetics of a 3-hoUrlY fall of 12.3 mb at storm Carrie. On satellite pictures, the storm appeared to
northwest winds over Bravo delayed further intensifica- be "torn apart." Holvever, on September 2 Carrie gained
tion until late on the 26th when acceleration and intensifi- strength again with the approach of a neIv trough in the
cation took place in advance of another deepening trough. westerlies. Under the influence of baroclinic processes, it On the morning of the 27th, military reC0nnaiSSanCe air- began losing its tropical characteristics, and, by late
craft found a central pressure of 987 mb and maximum afternoon, a reconnaissance plane could find no evidence
sustained winds of 85 kt. The first satellite Picture of the of tropical properties, although the central pressure had
day clearly showed an eye, and reconnaissance reports dropped to 992 mb. The center finally crossed the coast
indicated a classic eyewall. At this time, subtropical near Eastport, fi/Iaine, on the morning of the 4th and
cyclone &avo became hurricane Betty in the north gradually weakened as it proceeded up the Gulf of
central Atlantic about 800 n.mi. west of the Azores. St. Lawrence.
Records indicate that this is the highest latitude a t which ~~l~ Ivarnings were issued from cape M ~~, N. J., to
a storm ever first became a hurricane. Steady deepening Eastport, fi/Iaine, as the storm moved northward. The
maximum sustained winds Of kt were reported late On the north on Cape Cod and the highest measured gust was
the 27th. 73 kt at Point Judith, R.I. Northerly gales of 45-55 kt
After the short-wave trough in the westerlies Passed were reported over most of Cape Cod, and four lives were
by the hurricane, unfavorable northerly winds aloft lost in that area as numerous small boats, especially at
restricted the outflow of warm air from Betty with Rockport, Mass., mere capsized. Gales of 35-45 k t also
subsequent weakening. As pressures built to the east of the occurred along the Maine coast. Heavy rains of 6-9 in.
center, deceleration took place. By the morning of the fell on Cape Cod with amounts of 2-4 in. recorded in the
30th, Betty turned back to the west, after coming within Boston, Mass., area on September 3. Most of the $1.78
150 n.mi. of the island of .Corvo in the Azores. Later that million damage associated with Carrie was in Massa-
day, winds dropped below hurricane force, and by late on chusetts, with lesser amounts elsewhere on the New
the 31st they were barely of tropical stoim strength. The England coast.
storm accelerated northward ahead of another approaching
trough and deepened to 998 mb, becoming extratropical Hurricane Dawn, September 4-14
about 500 n.mi. northwest of Corvo on the morning of
September 1. Military reconnaissance reports indicated
that maximum winds had increased to 70 kt.
No warnings other than marine were required and no
deaths or damage associated with Betty have been
reported.
Tropical Storm Carrie, August 29-September 5
The seedling disturbance from which Carrie orkinated
is not easily traceable. A strong disturbance moved off the
African coast on August 15, reached the Leeward Islands
on the 25th 8s a weak system, and then, under the influence
of an upper cold Low near Hispaniola, almost disappeared.
northwestward just off the southeast Florida coast, and
convection was increasing. From thermal winds on the
National Hurricane Center (NHC) shear chart, it ap-
peared to remain a cold-core system. The disturbance
a trough at higher latitudes. A closed circulation in lower
layers first appeared early on the 29th, and, on the 31st,
military reconnaissance aircraft reported sustained winds
332 / Vol. 101, No. 4 / Monthly Weather Review
D~~ to an unfavorable
took place until the lowest central pressure Of 976 mb and strongest wind reported along the coast \vas 60 kt from
Dawn was similar to Carrie in its origin, growth cycle,
and subsequent weakening under the influence of unfavor-
able baroclinic circulations. Carrie, however, survived these
unfavorable conditions while Dawn did not.
A strong tropical wave moved off the African coast on
August 28, gradually weakening as it crossed the Atlantic
a t a rapid pace. It reached the eastern Caribbean on
September 1. Here, it interacted with the semipermanent
upper tropospheric trough and its movement was retarded.
On September 2, upper air data sho\ved that the disturb-
ance had a warm core. As a trough at higher latitudes
moved into Nabama on September 4, the tropical disturb-
ance became stationary near the southeast Florida
similar to those that occurred during the development
of Carrie. Although tropospheric temperatures rose
over southeastern Florida, the wind shear in the vertical
sion resumed its northward movement On September 5,
intensification began, and Dawn became a named storm
the following day when a military reconnaissance aircraft
'
BY the 28th, the complex LOw remained had drifted coast and convection increased-a sequence of events
began moving northward on the 29th with the approach of also increased, inhibiting storm develoPment* The depres-
reported sustained winds of 50 k t near the center 200
n.mi. east of Cape Hatteras.
As Dawn moved northeastward on September 7,
the circulation in the westerlies to the north generated
a cold Low near Cape Hatteras. This Low profoundly
influenced the future course and development of Dawn,
which reached minimal hurricane strength on the 7th
and was subsequently diverted from its northeastward
course, first to the west and then to the south, due to
interaction with the cold Low. Maximum flight-level
winds observed were 70 k t late on the 7th, although the
lowest central pressure of 997 mb occurred on the morning
of the 8th.
In contrast to Carrie, which was steered rapidly into
New England under the influence of an approaching
trough in the westerlies, Dawn remained under the
influence of the cold Low, which did not relinquish its
grip until Dawn had been steered southward to the 32d
parallel. Thereafter, it moved westward to the Georgia
and South Carolina coasts, losing strength along the
way.
Dawn was a trivial hurricane with trivial consequences.
However, the influence of the rapidly developing cold
Low on its movement, which was not anticipated by
but none were reported on the mainland. No significant
damage or loss of life occurred with Dawn.
ACKNOWLEDGMENTS
Portions of this report are based on preliminary accounts of
individual storms prepared by NHC staff members G. B. Clark,
N. L. Frank, and J. M. Pelissier. Portions of the data in tables 1
and 2 were furnished by R. M. DeAngelis of EDS, NOAA.
REFERENCES
DeAngelis, Richard M., and Hodge, William T., Prelimirary
Climatic Data Report-Hurricane Agnes June 14-23 1972,
NOAA Technical Memorandum NOAA TM EDS NCC-1, National
Climatic Center, Asheville, N.C., Aug. 1972, 62 pp.
Frank, Neil L., Atlantic Tropical Systems of 1972, Monthly
Wcather Rcvzew, Vol. 100, No. 4, Apr. 1973, pp. 334-338.
Gray, William M.; Global View of the Origin of Tropical Dis
turbances and Storms, Atmospheric Science Papers No. 114,
Colorado State University, Fort Collins, Colo., Oct. 1967, 105 pp.
Hebert, Paul J., and Miller, Banner I., Hemispheric Circulation
and Anomaly Patterns Observed When Tropical Storms Reach
Hurricane Intensity, ESSA Technical Memorandum WBTM
SR-46, Weather Bureau, Southern Region, Fort Worth, Tex.,
May 1969, 9 pp.
Jarvinen, Brian R., Objectively Analyzed Sea-Surface Tempera-
tures and Anomalies,  NOAA Technical Memorandum, NWS
SR-70, Weather Service Southern Region, Fort Worth, Tex.,
>
any of the prediction techniques, resulted in the largeit
24-hr prediction errOrS in recent years, averaging 156
19737 PP.
Palmh, Erik H., On the Formation and Structure of Tropical
Hurricanes, Geophysics, No. 3, ~elsinki, Finland, 1948, pp.
n.mi. 26-38.
As Dawn turned toward the coast on September 8,
storm warnings were issued from Chincoteague Inlet,
to Morgans Inlet, NC*, and gale warnings
where from Cape May, N.J., to Cape Lookout, N-C.
Gales occurred along the outer banks of Cape Hatteras,
Simpson, R. H., and Hope, John R., Atlantic Hurricane Scason of
1971, Monlhly Feather Review, Vol. 100, NO. 4, Apr. 1972, pp.
Simpson, R. H., and Pelissier, Joseph M., Atlantic Hurricane
Season of 1970, Monthly Weather Rtwiew, Vol. 99, No. 4, Apr.
1971, pp. 269-277.
256-267.
[Received January 23, 19731
April 1973 Simpson and. Hebert 1 333