000 AXNT20 KNHC 160617 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Mon Dec 16 2024 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...SPECIAL FEATURES... Western Atlantic Large NE Swell: Large NE swell generated by earlier strong gale winds across the northern Atlantic is persisting across the western Atlantic. It is sustaining seas of 12 to 16 ft north of 24N between 64W and the Florida Coast/Bahamas. Fresh to strong ENE to E winds are also present in the area. As this swell steadily decays tonight and Monday, it should allow seas to subside below 12 ft by Monday evening. Please refer to the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFAT2.html and https://www.nhc.noaa.gov/marine/offshores.php for more detail. Eastern Atlantic Gale Warning: Meteo-France has issued Gale Warnings for their Marine Zones: IRVING, MADEIRA AND CANARIAS through 16/09Z to 16/18Z. Please refer to the website: https://www.wwmiws.wmo.int/index.php/metareas/affiche/2 for more information. ...MONSOON TROUGH/ITCZ... A monsoon trough lies mostly over the Africa Continent. An ITCZ extends west-southwestward from off the Sierra Leone coast at 06N14W through 05N30W to 02N47W. Scattered moderate convection is noted up to 110 nm along either side of the ITCZ west of 25W. ...GULF OF MEXICO... A broad surface ridge extends southwestward from a 1033 mb high over the southeastern U.S. to a 1019 mb high near Veracruz, Mexico. Fresh to strong NE to ENE winds and seas of 6 to 9 ft are present at the southeastern and east-central Gulf, including the Florida Straits and Yucatan Channel. Moderate to fresh ENE to SE winds and 4 to 6 ft seas are noted at the northeastern and northwestern Gulf. Gentle to moderate ENE to ESE winds with seas at 3 to 5 ft prevail for the rest of the Gulf. For the forecast, the aforementioned surface ridge will continue to support fresh to strong NE to E winds and moderate to rough seas over the eastern Gulf, including the Straits of Florida through Mon. Then, gentle to moderate winds and slight to moderate seas are expected through Wed. Looking ahead, a weak cold front will reach the northwestern Gulf by Wed night and dissipate over the northern Gulf by early Thu. High pressure in the wake of the front will bring gentle to moderate northerly winds and slight to moderate seas Thu through Sat. ...CARIBBEAN SEA... A surface trough reaches southward from a 1011 mb low near the eastern tip of Cuba to southeast of Jamaica at 15N76W. Scattered showers and isolated strong thunderstorms are occurring over the Windward Passage and waters near Jamaica and Haiti. Convergent trade winds are causing isolated thunderstorms across the eastern basin, including waters near Puerto Rico and the Virgin Islands. Fresh to strong NE winds and seas of 5 to 7 ft are evident at the northwestern basin. Gentle to moderate NE to E winds and 3 to 5 ft seas prevail elsewhere in the Caribbean Sea. For the forecast, a strong pressure gradient will continue to induce fresh to strong NE winds in the lee of Cuba, and over the northwestern basin through Mon morning. A surface trough over the western Atlantic waters extending into the Caribbean through Hispaniola will drift westward across the central basin through Tue, likely reaching the northwestern basin on Wed. High pressure will build in the wake on the trough, and produce fresh to strong trades over the central basin mainly at night Mon through Thu. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section at the beginning about large NE swell. A surface trough extends northeastward from a 1011 mb low near the eastern tip of Cuba to 27N68W. Scattered moderate convection is flaring up from 20N to 27N between 58W and 70W. Convergent trades are triggering similar convection near the northern Leeward Islands. Gentle to moderate E to SE winds and seas of 6 to 10 ft in moderate to large mixed swell are noted from 20N to 24N between 55W and the Great Bahama Bank. For the central Atlantic, gentle NNE to E winds and 7 to 11 ft seas in large northerly swell are found north of 20N between 35W and 55W/64W. In the Tropical Atlantic from 04N to 20N between 35W and the Lesser Antilles, gentle to moderate NE to ENE winds and seas at 5 to 8 ft in mixed moderate swells exist. Gentle to moderate SE winds and seas of 4 to 6 ft in mixed moderate swells prevail for the remainder of the Atlantic Basin. For the forecast W of 55W, the tight pressure gradient between strong high pressure over the eastern U.S. Seaboard and the aforementioned 1011 mb low/surface trough will continue to support fresh to strong NE winds and very rough seas over most of the waters west of 65W. These hazardous marine conditions will gradually diminish late tonight into Mon. Fresh to locally strong E winds will prevail east of the Bahamas through Wed as a ridge builds towards the western Atlantic. Looking ahead, the next cold front is forecast to move off the northeastern Florida offshore waters Wed night, reach from near 32N71W to the central Bahamas by late Thu night and then stall. A strong cold front may quickly merge with the stalled front late on Fri, followed by fresh to strong NW winds. $$ Chan