[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211100
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
700 AM EDT Tue Apr 21 2020

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 0600 UTC surface analysis and satellite imagery through
1045 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends southwestward from the coast of
Sierra Leone near 08N13W to 05N16W and to 01N22W, where an
overnight scatterometer pass indicates that it transitions to
the ITCZ and continues to 01N33W, to 00N38W and to 00N50W.
Scattered moderate to isolated strong convection is within
240 nm south of the ITCZ between 33W-41W. Scattered moderate
convection is within 240 nm southeast of the trough between
the coast of Liberia and 12W. Similar activity is north of the
ITCZ within 60 nm of line from 03N32W to 04N38W and to 04N43W,
and within 60 nm north of the trough between 20W-22W.

A large area of scattered moderate to isolated strong convection
is noted well to the south of the monsoon trough from 07S to 02S
and between 14W-22W.

GULF OF MEXICO...

As of 21/0900 UTC, a cold front extends from Naples, Florida to
24N89W. NWS mosaic radar imagery shows scattered showers along
the front east of 84W. Moderate southwest winds are ahead of the
front over the SE Gulf. The northern Gulf is under the influence
of weak surface high pressure ridging as 1014 mb high is analyzed
just southeast of Louisiana. The associated gradient is providing
for gentle winds over the waters north of 27N and east of 93W.
Gentle to moderate winds are west of 93W.

Large areas of smoke, some in the dense category, are observed
over the just about the entire south-central and SW Gulf sections.
Surface visibility reduction is estimated at 4 nm in these
sections of the Gulf.

The forecast calls for the cold front to exit the area this
afternoon. The next cold front is forecast to approach the NW Gulf
late Wed night into Thu morning. Fresh to strong southerly winds
are forecast to develop ahead of the front over the western half
of the Gulf by tonight. The front will reach from the western
Florida panhandle to near 26N92W by Thu night, then from Apalachee
Bay to the central Gulf and stationary to eastern Mexico early
Fri. This front is expected to shift east of the area Fri night.
Scattered showers and thunderstorms may precede this front. Yet
another cold front is expected to emerge off the Texas coast and
over NW Gulf late Fri night into early Sat.

CARIBBEAN SEA...

A surface ridge extends from near 24N60W to Cuba. Overnight
scatterometer data revealed moderate to fresh trade winds across
the eastern Caribbean east of 75W. Mainly fresh east to southeast
trade winds are in the Gulf of Honduras and in the south-central
Caribbean section. Moderate winds are elsewhere. Aside from
isolated showers over the Leeward Islands, most of the basin is
dry due to strong subsidence from persistent deep-layer ridging.

The forecast calls for the fresh trade winds in the south-
central Caribbean and in the Gulf of Honduras to increase to
strong speeds at night through Wed night, then change little
through Sat as stronger high pressure builds north of the area.
Elsewhere, gentle to moderate trade winds will increase to
moderate to fresh speeds beginning on Thu and continue through
Sat. The fresh trade winds in the eastern Caribbean will change
little through the end of the week.

ATLANTIC OCEAN...

As of 21/0900 UTC, a cold front approaching Bermuda stretches
southwestward to 32N66W, to West Palm Beach and to Naples,
Florida. A vigorous mid-level trough is passing over the front
near 70W. This feature is significantly contributing to the
longevity of a rather impressive solid line, about 180 nm wide,
of numerous strong thunderstorms containing frequent lightning.
The line extends 300 nm to the east of front north of about 27N.
Scattered showers and thunderstorms are seen within 180 nm east of
the front from 24N to 27N. Overnight Ascat data shows strong
southwest winds east of the front to about 65W and north of 27N.
The Ascat pass shows fresh northwest to north winds west of the
front to near 78W. A surface ridge extends from 25N60W to Cuba. It
is maintaining rather tranquil conditions over the southeastern
and central Bahamas.

The forecast calls for the aforementioned cold front to reach
from near 31N70W to the NW Bahamas and to South Florida around
or shortly after daybreak this morning, then reach from near
32N68W to the Central Bahamas and to along the coast of Cuba this
evening. The front will reach from near 28N65W to the SE Bahamas
and to eastern Cuba early Wed, then weaken as it moves east of the
forecast waters Wed night. Fresh to strong southwest winds will
precede the front mainly north of 27N. Another cold front is
forecast to move over the northwest part of the offshore waters
Thu night. Strong to possibly near gale force southerly winds will
precede the front and are expected over the waters north of the
Bahamas from Thu morning through Fri morning. Scattered showers
and thunderstorms may accompany this front. High pressure will
build in behind the front.

Farther east, a ridge extends from a 1025 mb high near 34N22W to
28N32W, then to a 1024 mb high near 27N42W and to 25N60W. A 1023
mb high center is north of the area at 33N47W. In between the
1023 and 1024 mb high centers, a dissipating cold front is
analyzed from near 32N38W to 30N48W. Moderate to fresh southwest
winds are within 120 nm southeast of this front, north of 30N and
east of 38W. These winds are diminishing with time. A warm front
extends from 32N28W northwestward to a triple point at 36N31W.
Areas of rain along with embedded scattered showers and possible
isolated thunderstorms are observed north of 30N between 22W-30W.
Scattered showers and isolated thunderstorms are north of 29N
between 30W-34W.

Patches of low-level clouds quickly moving westward in the trade
wind flow are present from 07N to 23N and west of 25W. Isolated
showers are possible with these clouds.

$$
Aguirre
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