[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152316
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Apr 16 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.

...SPECIAL FEATURES...

Eastern Caribbean Ashfall Advisory: An Ashfall Advisory has been
reissued for La Soufriere Volcano on the island of St. Vincent
near 13.3N 61.2W. Latest forecast indicates that the ash cloud is
now moving N and then NNE toward Dominica. Intermittent volcanic
ash emissions are expected through 16/0900Z. The volcano remains
in a state of unrest. Additional eruptions and ash plumes are
possible. Mariners transiting the nearby waters should exercise
caution, and are encouraged to report volcanic ash to the
National Hurricane Center by calling 305-229-4424.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic ocean through the coast
of west Africa near 12N16W and continues SW to 08N18W. The ITCZ
continues from 08N18W to 02N30W to the coast of South America
near 02N51W. Scattered moderate convection is seen from 04N-05N
between 11W-20W, from 02N-05N between 20W-31W, and from 00N-04N
W of 37W to the coast of South America.

GULF OF MEXICO...

Strong to severe thunderstorms were noted this morning over the
northern Gulf waters ahead of a cold front that now extends from
the Florida Panhandle to near Corpus Christi, Texas. Currently,
some shower activity is occurring over the NE Gulf. Scatterometer
data provided observations of strong to minimal gale force winds
near the coast of Louisiana in association with the above
mentioned convective activity. Fresh SE winds are seen west of the
Yucatan Peninsula. Seas are 3-5 ft across the basin, but locally
higher seas are possible in thunderstorms. The front will stall
and weaken along 27N tonight. Areas of smoke and haze in the
western Gulf may reduce visibilities.

A stronger cold front will move into the NW Gulf on Sat, with
strong northerly winds and building seas expected across the
western Gulf this weekend. Gale force winds are possible near the
central coast of Mexico Sat night with seas building up to 11 or
12 ft. The front will stall from central Florida to the Bay of
Campeche Sun night through early next week.

CARIBBEAN SEA...

An Ashfall Advisory is in effect for La Soufriere volcano on the
island of St. Vincent. See the special features section above
for details.

Weak ridging dominates Cuba and the NW Caribbean, with mainly
fair weather and moderate E trades. Showers and thunderstorms
continue to flare up over Costa Rica and Panama and regional
coastal waters. Farther east, the tail end of an Atlantic
stationary front reaches the Lesser Antilles over Guadeloupe,
where some low level clouds with possible showers are noted.
The most recent satellite derived wind data show fresh to locally
strong NE winds just south of Dominican Republic and downwind to
near 14N. Moderate to fresh trades cover the remainder of the
east and central Caribbean, with gentle to moderate E to SE
winds over the NW Caribbean. Seas are 4-7 ft over the central
Caribbean and 2-5ft elsewhere.

A stationary front northeast of the Windward Islands will continue
to weaken tonight. Moderate to fresh trade winds, locally strong,
will prevail across the Caribbean through Sun. Fresh to strong
SE winds are expected in the NW Caribbean this weekend, and then
again Tue night. Fresh to strong trade winds will prevail across
the central Caribbean Sun night through early next week.

ATLANTIC OCEAN...

An Ashfall Advisory remains in effect for La Soufriere Volcano
on the island of St. Vincent. Please refer to the Special
Features section above for more details.

West of 65W: A weak pressure gradient dominates the waters W of
65W under the influence of a 1017 mb high pressure located near
26N65W. The latest ASCAT pass shows fresh to strong SW winds to
the east of northern Florida, mainly north of 29N between 76W-
81W ahead of a frontal boundary that crosses the state of
Georgia. Scattered showers are seen mainly north of central
Florida. For the forecast, a cold front will move east of
northern Florida into the northern waters by early Fri, then
stall north of the Bahamas this weekend into early next week.

East of 65W: A pair of cold fronts are moving across the central
Atlantic waters. The primary cold front extends from 31N40W to
near Guadeloupe, in the Lesser Antilles. The second cold front
enters the forecast waters near 31N46W and continues SW to near
21N60W. This front is dissipating. Scattered moderate convection
is noted ahead of the first front, particularly N of 20N E of
front to 40W. Moisture associated with the primary front will
lift northward and will continue to affect the Leeward Islands on
Fri.

The remainder of the Atlantic forecast area is under the influence
of 1022 mb high pressure located just south the Azores. The
pressure gradient between this system and lower pressure over
west Africa is resulting in fresh trade winds from 10N-20N E of
35W based on scatterometer data. By Fri night into Sat, the
trade wind flow will increase some between 35W and 50W as high
pressure builds toward the NE Caribbean.

$$
GR
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