[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091750
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Mon Aug 9 2021

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
1700 UTC.

...SPECIAL FEATURES...

Showers and thunderstorms associated with the area of low pressure
located about 100 miles east-northeast of Barbados continue to show
signs of organization. However, recent satellite wind data indicates
that the system currently lacks a well-defined center.
Environmental conditions are expected to remain conducive for
additional development, and a tropical depression is likely to form
later today or tonight while the low moves west-northwestward at 10
to 15 mph. The disturbance is forecast to move through portions
of the Lesser Antilles tonight, then move near the Virgin Islands
and Puerto Rico on Tuesday, and Hispaniola on Wednesday. Tropical
storm watches or warnings could be required this afternoon with
shorter-than-normal lead times for portions of the Lesser
Antilles, the Virgin Islands, and Puerto Rico. In addition, heavy
rains and flooding are likely for the Leeward Islands, Virgin
Islands, and Puerto Rico. Interests in those areas should monitor
the progress of this system. Fresh to strong winds with seas of
7-10 ft are analyzed near and south of the low pressure center.
This system has a high chance of becoming a tropical cyclone
during the next 48 hours. Please refer to Tropical Weather Outlook
at www.hurricanes.gov and the High Seas Forecast issued by the
National Hurricane Center at www.nhc.noaa.gov/MIAHSFAT2.html for
more information.

...TROPICAL WAVES...

An eastern Atlantic tropical wave recently moved off the coast of
Africa, and is currently analyzed along 18W from 22N southward.
Scattered showers are noted from 09N to 14N east of 24W.

The axis of a tropical wave is near 36W from 21N southward,
moving W at 10-15 kt. No convection is noted with the tropical
wave at this time.

The axis of a tropical wave is near 54/55W from 24N southward,
moving W at 10 to 15 kt. Scattered moderate to isolated strong
convection is noted from 11N to 15N between 55W an 60W.

The axis of a tropical wave is near 72W from 21N southward,
moving W at 10-15 kt. Scattered moderate convection is noted from
15N to the Caribbean coast of Hispaniola between 69W and 73W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through Mauritania near 20N16W to 13N30W
to 09N46W. The ITCZ then continues from 09N46W to 10N53W. Aside
from convection described above in the Special Features and
Tropical Waves sections, scattered moderate convection is
observed near the ITCZ from 06N to 10N between 46W and 52W.

...GULF OF MEXICO...

As of 1500 UTC, 1021 mb high pressure is centered in the NE Gulf
near 29N87W. Ridging from this and the subtropical high dominates
the Gulf waters, supporting quiescent conditions. Scattered
moderate convection is noted from 24N to 25N between 84W and 89W. Light
anticyclonic winds are observed in the NE Gulf near the high
center. Gentle to moderate E to SE winds are found elsewhere in
the Gulf. Seas are 3-5 ft in the NW Gulf, 2-4 ft in the SW and
central Gulf, and 1-3 ft in the E Gulf.

For the forecast, moderate to fresh E winds will pulse off the NW
Yucatan Peninsula into the Bay of Campeche each night through Tue
night in association with a diurnal trough. Elsewhere, a weak
surface ridge along 27N will dominate the Gulf waters today, and
drift northward to along 29N-30N Tue through Thu.

...CARIBBEAN SEA...

Please see the Special Features section for information on a low
pressure system with a high chance of developing into a tropical
cyclone.

High pressure prevails north of the area. Scattered moderate
convection, likely enhanced by the East Pacific Monsoon Trough,
is noted over the Isthmus of Panama and the SW Caribbean, from 07N
to 10N between 78W and 82W. Fresh to locally strong trades were
observed by the scatterometer over the south central Caribbean.
Moderate to fresh trades prevail elsewhere in the basin, except
in the NW Caribbean where trades are gentle to moderate. Seas are
5-7 ft near the Lesser Antilles, 4-6 ft in the central Caribbean,
3-5 ft in the SW Caribbean, and 2-4 ft in the NW Caribbean.

For the forecast, fresh to strong trade winds will pulse over the
south-central Caribbean tonight and Tue night. A strong tropical
wave with very active weather across the tropical Atlantic waters
today will move across the Lesser Antilles tonight and across the
NE Caribbean early Tue through Wed. 1010 mb surface low pres near
13N57.5W associated with this system is moving W-NW 12 kt and
expected to develop into a Tropical Depression later today or
tonight. Caribbean interests should closely monitor this system.
This low will likely move near or across Hispaniola Wed.

...ATLANTIC OCEAN...

Please see the Special Features section for information on a low
pressure system with a high chance of developing into a tropical
cyclone.

The subtropical highs centered near 34N45W and 36N35W dominates
the tropical Atlantic. Light to gentle E to SE winds prevail over
the waters north of 23N and west of 57W, with moderate to locally
fresh trades from 15N to 23N, and gentle to moderate trades south
of 15N across the basin. Seas are 2-5 ft north of 22N and west of
65W, and generally 4-7 ft elsewhere in the discussion waters
outside of the area described in the Special Features section.

For the forecast W of 65W, the Atlc surface ridge associated with
the Bermuda-Azores high will persist with axis N of the area for
the next several days. A strong tropical wave with very active
weather is expected to move across the SE Atlantic waters tonight,
across the NE Caribbean and adjacent Atlantic waters Tue and Tue
night, and reach the SE Bahamas Wed night. A 1010 mb surface low
associated with this system is moving W-NW 12 kt and is likely to
develop into a Tropical Depression later today or tonight. This
system is expected to move near or across Hispaniola on Wed.

$$
Mahoney
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