[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120512
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Mon Apr 12 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 0000 UTC surface analysis and satellite imagery through
0430 UTC.

...SPECIAL FEATURES...

Windward Islands Ashfall Advisory: La Soufriere volcano on the
island of Saint Vincent near 13.3N 61.2W is currently undergoing
frequent eruptions. Volcanic ash may be reaching the ocean
surface and low level visibility may be reduced. Mariners
traveling within the area 18N35W to 14N55W to 13N62W to 10N56W
to 06N37W to 18N35W are urged to exercise caution. The densest
ash is west of 48W. If mariners encounter volcanic ash or
floating volcanic debris, you are urged to report the
observation to the National Hurricane Center by calling
305-229-4424.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends southward from the coast of
Senegal near 13N17W to 05N21W. The ITCZ continues from 05N21W to
00N30W to 00N45W. Scattered moderate and isolated strong
convection is from 05S-02N between 18W-32W.

GULF OF MEXICO...

A weak cold front extends from a 1005 mb low pressure near
Apalachicola Florida to 26N90W to 25N95W, then stationary to a
1000 mb low pressure inland over Mexico near 25N101W. A recent
ASCAT pass shows gentle wind speeds on both sides of the front.
The cold front will stall out from central Florida to the Bay of
Campeche today and dissipate by tonight. A squall line oriented
east-west off the coast of Naples Florida is producing numerous
moderate and scattered strong convection from 25N-27.5N between
81W-86W, as of 0430 UTC. During the last 6 hours, the squall
line has been moving slowly southeastward at 10 kt while
changing little in intensity. It has been producing frequent
lightning and gusts to 40 kt. This activity is being enhanced by
an upper-level shortwave trough. Expect the thunderstorms over
the eastern Gulf to weaken later this morning. Scattered
moderate showers extend eastward from the squall line over South
Florida. Elsewhere, a weak surface trough is located in the SW
Gulf of Mexico with axis extending from 25N90W to 21N94W. Seas
are 3-5 ft across the Gulf of Mexico, except 1-3 ft in the
southern Bay of Campeche.

CARIBBEAN SEA...

See the Special Features section above for details on an Ashfall
Advisory issued for ongoing volcanic eruptions on St. Vincent.

The latest surface analysis depicts a rather weak pressure
gradient across the basin. A recent ASCAT pass shows fresh
trades over the central Caribbean and Gulf of Honduras, with
moderate winds elsewhere. Mainly fair weather conditions are in
place across the basin, except for a few scattered showers off
the coasts of Costa Rica and Panama. Wave heights are in the 4-6
ft range across most of the basin, except locally up to 7 ft in
the south-central Caribbean.

For the forecast, fresh southeast winds are expected over the
northwestern Caribbean through the 5-day forecast period, with
fresh to strong east to southeast winds in the Gulf of Honduras.
Winds will pulse to strong speeds over a small area near the
coast of Colombia during the afternoons and at night through
Thu. Elsewhere, generally moderate to fresh east winds will
change little through Fri night.

ATLANTIC OCEAN...

See the Special Features section above for details on an Ashfall
Advisory issued for ongoing volcanic eruptions on St. Vincent.

A surface trough extends from 30N74W to the N coast of Cuba near
23N79W. Upper-level diffluence to the east of Florida is
enhancing a cluster of moderate to strong thunderstorms
currently impacting the central Bahamas area, as of 0400 UTC.
This cluster of storms should weaken later this morning.
Scattered moderate showers and isolated tstorms are occurring
elsewhere west of 70W from 23N-32N. ASCAT shows fresh to locally
strong S to SW winds to the east of Florida, mainly north of 26N
extending to 70W. A 1016 mb high pressure is centered near
28N62W. The high extends a ridge axis to the SE Bahamas. ASCAT
shows moderate anticyclonic winds to the east of the SE Bahamas.
Seas are 6-8 ft north of the Bahamas between 70W-77W.

For the forecast west of 65W, fresh to strong southwest winds
east of Florida will shift eastward today ahead of a cold front
that will move off the southeastern U.S. coast this morning. The
front will reach from near 31N75W to east-central Florida by
late this morning and from near 31N70W to the central Bahamas to
east-central Cuba this evening. The front will move east of 65W
on Wed as weak high pressure builds in behind it over the
western Atlantic. Another cold front is expected to cross the
waters to the north and northeast of the Bahamas on Tue. Fresh
to strong southwest winds are expected to precede this front.

Farther east, a surface trough extends from 26N45W to 23N57W,
with isolated showers near its axis. Another surface trough
extends from 27N30W to 16N52W. Upper-level diffluence is
sparking scattered moderate showers and tstorms along and east
of this surface trough axis, mainly east of 42W from 20N-29N. A
recent ASCAT pass shows fresh to strong W winds north of 29N
between 30W-42W associated with a low pressure system north of
our discussion area. Seas are 10-12 ft in this area. Northerly
swell over the central Atlantic will diminish today as the low
moves NE and weakens. A 1020 mb high is located over the Canary
Islands. A surface ridge with light to gentle winds extends from
this high to 18N47W to 22N59W.

$$
Hagen
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