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Atlantic Tropical Weather Discussion



442 
AXNT20 KNHC 212314
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Apr 22 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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Guinea near 11N15W
and continues SW to 03N22W. The ITCZ extends from 03N22W to 01N35W
to the coast of Brazil near 00N50W. Scattered moderate and isolated
strong convection is from 00N-06N between 10W-30W, from 00N-03N 
between 30W-36W, and from 00N-03N between 45W-49W.

GULF OF MEXICO...

A cold front extends from Naples, Florida southwestward to 
the eastern Bay of Campeche near 21N92W. Scattered showers with
embedded thunderstorms is ahead of the frontal boundary over the
SE Gulf. This convective activity is reaching the northern coast
of western Cuba. Another cold front extends from the Florida Big
Bend to just south of Brownsville, Texas. Cold air stratocumulus
clouds are noted behind the front, particularly W of 90W as seen
on visible satellite imagery. Fresh north to northeast winds 
follow the fronts. Winds and seas could be higher near tstms in
the SE Gulf. 

The first front will exit the SE Gulf this evening. The second 
cold front will reach from west-central Florida to the central 
Gulf by late tonight, then weaken early Thu as it reaches from 
southwest Florida to near 23N90W. Fresh to strong southerly 
return flow will develop over the western Gulf Fri, shift to the 
central Gulf early Sat and diminish late Sat as another cold 
front enters the far NW Gulf. This front will move across the 
rest of the Gulf waters through Sun night as it weakens. In its 
wake, high pressure will shift eastward across the Gulf region 
through Mon night. 

CARIBBEAN SEA...

The most recent satellite derived wind data provided observations
of fresh to strong trades over the south-central Caribbean, with
near-gale force winds within about 90 nm of the coast of Colombia.
Moderate to fresh trade winds were noted elsewhere, with the
exception of light and variable winds across the Windward Passage,
and an area of fresh easterly winds across the Leeward Islands
and regional waters, including the Anegada Passage. Seas are in
the 6-9 ft range over the south-central Caribbean, 4-6 ft elsewhere
over the eastern and central Caribbean, and 3-5 ft over the NW
part of the basin. Patches of low level moisture embedded in the
trade wind flow are currently reaching Puerto Rico and the US/UK
Virgin Islands producing isolated to scattered passing showers.

Fresh to strong trade winds over the central Caribbean will diminish
slightly late in the week as high pressure over the central Atlantic
shifts eastward, except near the coast of Colombia where these winds
will persist through the week. Seas are also forecast to subside
from 7-10 ft tonight to 5-7 ft by Fri night near the coast of 
Colombia.

ATLANTIC OCEAN...

W of 65W, a cold front extends from 31N70W to South Florida into
the Gulf of Mexico. Some shower activity is associated with the 
front, forecast to weaken as it reaches from near 31N67W to 
central Cuba by early Thu. At the same time, a second cold front 
that will move off the southeastern U.S. coast this evening will 
reach from near 31N70W to South Florida on Thu. The second front 
will merge with the remnants of the first front Thu afternoon, 
reaching from 31N65W to the Straits of Florida by Thu evening. 
The merging front will weaken as it moves across the waters NE of
the Bahamas through late Fri. Fresh to strong NW winds are 
expected in the wake of the second front tonight into early Thu 
morning with seas of 6-7 ft. High pressure will follow the 
merging front and will dominate the waters W of 65W Thu night 
through Sat. 

On Sat night, a stronger cold front is expected to approach the 
southeastern U.S. coast and move across the waters NE of the 
Bahamas through Mon night while weakening. Fresh to strong 
southerly winds will develop over the waters N of 27N and W of
70W Sat and Sat night. The forecast currently calls for southerly
winds of 20-30 kt, and building seas in the 8-9 ft range. These
marine conditions will shift eastward, covering mainly the area
N of 27N between 65W and 75W through Sun night. Scattered showers
and thunderstorms are possible ahead of this front.

Elsewhere E of 65W, a 1023 mb high is centered near 26N40W with 
the associated ridge covering the remainder of the Atlantic
forecast waters. A storm force 992 mb low pressure is located 
north of the area. The attendant cold front enters the forecast 
region near 31N40W and extends along 29N50W to 29N58W. Seas 
generated by this storm are currently reaching the northern 
forecast waters E of 55W, building seas to 8-12 ft in NW swell. 

$$
GR