[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221127
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Jul 22 2023

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1115 UTC.

...SPECIAL FEATURES...

Tropical Storm Don is centered near 38.3N 49.6W at 22/0900 UTC or
about 530 nm SSE of Cape Race, Newfoundland moving NW at 12 kt.
Estimated minimum central pressure is 998 mb. Maximum sustained
wind speed is 50 kt with gusts to 60 kt. Satellite imagery shows
numerous moderate convection confined within 75 nm of the center
in the SE quadrant and within 60 nm of the center in the NE
quadrant. This convection denotes a wide convective band that
just about wraps around the system's center. Don is forecast to
turn to the north later today, followed by a turn to the
northeast on Sun. Some slight strengthening is possible today.
however, weakening is forecast to begin by tonight or on
Sun morning. Don is expected to become a post-tropical cyclone on
Sun or Sun night.

Please read the latest HIGH SEAS
FORECAST issued by National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S.
Don Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Central Tropical Atlantic (AL95):
A 1012 mb low pressure is in the central tropical near 12N41W in
the central Atlantic. Easterly wind shear is displacing deep
convection within 180 nm west of the system center. This
convection consist of the numerous moderate to isolated strong
type from 11N to 13N between 42W-45W. Newly formed isolated
moderate convection is within 30 nm of 12N42W. Fresh, to at times
strong, northeast to east winds are north of the low along with
seas of 4-7 ft. Although environmental conditions are only
marginally conducive, some additional gradual development is
anticipated and this system will likely become a tropical
depression by early next week while it moves westward across the
tropical Atlantic. Interests in the Lesser Antilles should
monitor the progress of this system. The disturbance has a medium
chance of development over the next 48 hours. Refer to the latest
Tropical Weather Outlook at www.hurricanes.gov for more details.

Gale Warning E of 35W:
The strong pressure gradient between a 1030 mb high pressure near
the Azores and lower pressures over NW Africa has induced fresh to
near gale-force northerly winds in the eastern Atlantic, mainly
north of 17N and east of 25W. The strongest winds are present off
the coast of Morocco and Western Sahara and in the water passages
of the Canary Islands. Seas in the affected area are 6-10 ft.
Meteo-France is forecasting frequent gusts to gale force and rough
to very rough seas in the Agadir and Canarias Marine Zones until
23/0300 UTC. Please read the High Sea Forecast and Warning at
https://wwmiws.wmo.int for more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has its axis along 31W/32W from
05N to 19W. It is moving westward at 10-15 kt. Isolated showers
and thunderstorms are within 240 nm west and 120 nm east of the
wave from 06N to 12N.

A central Caribbean tropical wave has its axis along 81W and south
of 19N. It is moving westward at 10-15 kt. The interaction
between the wave axis and the eastern Pacific monsoon trough is
producing scattered showers and a few thunderstorms along the
coast of southern Costa Rica and along the coast of northern
Panama.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis reaches the Atlantic through the coast of
Mauritania near 19N16W. It continues southwestward to 11N23W, then
to 13N34W to the SPECIAL FEATURES low pressure near 12N41W and to
09N47W. Scattered moderate convection is from 04N to 11N and east
of 24W to the coast of Africa.

...GULF OF MEXICO...

A trough is over the Bay of Campeche from 22N92W to 19N93W.
Isolated showers and thunderstorms are presently over the central
and western sections of the Bay of Campeche. Weak high pressure
dominates the Gulf waters, with the associated gradient
resulting in moderate or weaker winds and 1-3 ft seas.

For the forecast, weak high pressure centered near the eastern Gulf
will remain remain dominate into early next week. This will
support mainly gentle to moderate winds, except over the eastern
Bay of Campeche where winds will be enhanced by a thermal trough
that will emerge off the Yucatan Peninsula during the overnight
hours.

...CARIBBEAN SEA...

Divergence aloft in the western Caribbean Sea in combination
with plenty of available tropical moisture support scattered
moderate to isolated strong convection, mainly west of west of 84W
and south of 21N. The remainder of the Caribbean Sea is under the
influence of a subtropical ridge positioned near the Azores. Dry
Saharan dust covers most of the eastern and central Caribbean,
resulting in drier conditions, above normal daily temperatures and
reduced visibility.

The pressure gradient between the ridge and lower pressures in NW
South America continue to sustain fresh to strong easterly trade
winds in the central Caribbean. Overnight partial ASCAT data
depicts some of these winds. The strongest winds are in the
south-central Caribbean. In the remainder of the basin, moderate
or weaker winds prevail. Wave heights are in the 8-11 ft range
over the central Caribbean and much lower in the 2-6 ft range
elsewhere.

For the forecast, the aforementioned pressure gradient
will maintain strong trades across the central Caribbean through
tonight. Winds should diminish slight to fresh to strong Sun
through Tue night. Fresh to locally strong trades will develop
over the Gulf of Honduras Sun through Mon. Low pressure, AL95,
well east of the region is forecast to move into Atlantic waters
E of the Lesser Antilles early next week, possibly as a tropical
cyclone. Expect increasing wind and seas over these waters in
association with this low pressure system.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section for information on
Tropical Storm Don in the north-central Atlantic, gale winds in
the eastern Atlantic, and INVEST 95L in the central Atlantic.

An upper-level trough between Bermuda and Puerto Rico is
producing scattered showers and thunderstorms north of 22N and
between 61W-67W. The rest of the tropical Atlantic is under the
dominance of a 1030 mb subtropical ridge centered near the Azores.
A large outbreak of Saharan dust (SAL) continues to propagate
across the central and eastern Atlantic suppressing the
development of showers and thunderstorms.

Numerous moderate convection, aided by a broad upper-level
trough, is just north of the discussion area west of 74W. This
activity is shifting eastward, and should remain quite active
through at least this evening.

The pressure gradient between the aforementioned ridge that
extends into the SW Atlantic and lower pressures over the eastern
United States is leading to moderate to fresh southwest to west
winds north of 27N and west of 66W. Seas over these waters are
4-7 ft. Moderate easterly winds and 2-4 ft seas are noted between
the SE Bahamas, northern Hispaniola and NE Cuba. Elsewhere west of
55W, light to gentle anticyclonic winds and slight seas prevail.
Over the remainder of the tropical Atlantic moderate or weaker
winds and slight to moderate seas are prevalent.

For the forecast west of 55W, weak high pressure of 1016 mb
centered near 24N67W will change little through the weekend.
Fresh trades just north of Hispaniola and over the Windward
Passage will diminish tonight. Elsewhere across forecast waters,
winds will be moderate or weaker into next week.

$$
Aguirre
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