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 night.


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.

$$ Hagen