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Atlantic Tropical Weather Discussion

AXNT20 KNHC 110514

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sun Apr 11 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 
0440 UTC.


East Atlantic Gale Warning: A recent ASCAT pass from around 
09/2200 UTC shows gale force SW winds from 28N-31N between 
30.5W-33W. These gales are occurring on the SE side of a large 
990 mb low pressure system centered near 36N45W. Seas are likely 
11-14 ft in the area of gale force winds. The MeteoFrance 
forecast indicates that the winds there will diminish below gale 
force soon.

Windward Islands Ashfall Advisory: La Soufriere volcano on the 
island of Saint Vincent near 13.3N 61.2W continues to undergo 
major eruptions. Satellite imagery shows the volcanic ash plume 
spreading well to the east and northeast of St. Vincent, roughly 
in an area from 10N-17N between 40W-62W, which includes 
Barbados. Violent volcanic eruptions may occur suddenly without 
warning. Volcanic ash may be reaching the ocean surface 
east-northeast of St. Vincent. Mariners should exercise caution, 
and report volcanic ash or floating debris to the National 
Weather Service by calling 305-229-4424. 


The monsoon trough extends southward from the coast of 
Guinea-Bissau near 12N16W to 04N23W. The ITCZ continues from 
04N23W to 02N35W to 01N48W. Isolated moderate convection is seen 
from 04S-04N between 18W-39W. Scattered moderate convection is 
noted from 05N-08N between 45W-57W.


A cluster of strong thunderstorms is located from 23N-26N 
between 81W-85W, including portions of the Florida Keys, as of 
11/0400 UTC. Wind gusts to 35 kt and frequent lightning are 
occurring. These storms are likely to weaken significantly 
within the next couple of hours, by 11/0700 UTC. A new cluster 
of strong to severe thunderstorms is expected to develop south 
of the Florida Panhandle around sunrise this morning. Expect 
these storms to persist over the NE Gulf of Mexico through the 
morning hours and into the afternoon, mainly north of 27N and 
east of 88W. The main hazards associated with these storms are 
likely to be wind gusts of 35-45 kt and frequent lightning. The 
storms will propagate toward the E-SE during the day.

Elsewhere over the Gulf, a stationary front currently extends 
from Lafayette Louisiana to Brownsville Texas. A surface trough 
is from 29N91W to a 1002 mb low near 21N96W. Scattered showers 
are seen from 26N-28N between 88W-92W. A recent ASCAT pass shows 
fresh E-SE winds over the east-central Gulf, with gentle to 
moderate winds elsewhere. Seas are 3-6 ft across the basin. 
Fresh southerly winds will prevail across the most of the basin 
this morning to the east of the stationary front. The front will 
move E as a cold front later today, then will stall again and 
weaken from the Florida panhandle to northern Mexico by Sun 


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

A recent ASCAT pass shows that fresh trades are occurring over 
most of the Caribbean Sea. Similar wind speeds will persist 
through the weekend. Seas are 3 to 6 ft. Scattered moderate 
thunderstorms are seen over NW Honduras and the Gulf of 
Honduras. No major precipitation areas are seen elsewhere over 
the basin. 


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

A line of scattered moderate showers and tstorms is weakening 
early this morning to the east of Florida as it moves eastward, 
from 26.5N-32N between 76W-79W. A recent ASCAT pass shows fresh 
to locally strong S winds occurring with these storms. A second 
cluster of showers and storms extends from the Dry Tortugas to 
Miami. This cluster will also weaken significantly during the 
next couple of hours. A third cluster of strong to severe 
tstorms is expected to develop in the NE Gulf of Mexico this 
morning. The storms will cross Florida and move into the 
Atlantic this afternoon. Expect wind gusts of 35-45 kt and 
frequent lightning this afternoon, especially in the waters 
extending offshore between Daytona Beach and West Palm Beach 
Florida. Outside of the thunderstorms, expect fresh southerly 
winds in the Bahamas and east of Florida today as a cold front 
approaches the western Atlantic. The front will move across 
Florida on Mon, then extend from 30N60W to 21N75W on Tue. Seas 
will build to 8 to 9 ft in the vicinity of the front. 

A large occluded gale-force low pressure system north of the 
area centered near 36N45W is producing a large area of strong 
westerly winds north of 26N between 30W-58W. Seas are 11-16 ft 
in this area. Northerly swell from this system, with seas in 
excess of 8 ft, is affecting most of the central Atlantic north 
of 21N between 26W-63W.

A 1019 mb high is centered near 30N69W. Gentle anticyclonic 
winds are found between 63W-72W. A surface trough extends over 
the central Atlantic from 25N37W to 16N53W. Upper-level 
diffluence to the east of the northeastern portion of the 
surface trough is enhancing scattered moderate showers and 
isolated tstorms from 20N-32N between 20W-40W. A 1018 mb high is 
centered near the Canary Islands.