000 AXNT20 KNHC 192141 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Dec 20 2023 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ..SPECIAL FEATURES... Central Atlantic Gale Warning: A 1011 mb low near 23N57W is steadily moving westward, while a broad surface ridge extends southwestward from a massive 1050 mb high over the north-central Atlantic to near 27N64W. The pressure gradient between these features is supporting gale force winds N of 28N between 48W and 54W. Seas over this area are in excess of 20 ft. As the low tracks farther westward and weakens this evening, winds are expected to decrease below gale force. Very Rough Seas across the Western and Central Atlantic: The pressure gradient responsible for the gale force winds discussed above is supporting a large area of strong to gale force winds, which extend N of the discussion area. These winds are generating large ENE to E swell across the central and western Atlantic. Seas greater than 12 ft associated with this swell is covering the waters N of a line from 31N34W to 20N55W to 31N70W. Seas are peaking near 21 ft in the area of gale force winds discussed above. Seas will gradually subside over the next few days, decreasing below 12 ft Thu night. Please read the latest NWS High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details on the Gale Warning and Very Rough Seas. ...MONSOON TROUGH/ITCZ... The monsoon trough remains over the African Continent. The ITCZ extends from 03N19W to 01N33W to 05N51W. Scattered moderate convection is noted from 06N to 19N between 20W and 30W. ...GULF OF MEXICO... A dissipating cold front extends from Central Florida to the central Gulf. Gentle to moderate winds prevail over much of the Gulf, except for gentle winds over the SW Gulf. Seas are in the 4-6 ft range E of 90W, and 2-4 ft W of 90W. For the forecast, strong high pressure will shift eastward across the central U.S. and into the eastern U.S.through Thu, causing fresh winds to veer E, with some strong winds developing in the Florida Straits and adjacent waters through Fri. SE return flow is expected to develop Sat. ...CARIBBEAN SEA... The southern portion of a stationary front extends from the Windward Passage to near 11N77W. Fresh to strong winds, and seas of 7-10 ft prevail S of 18N and west of the front, with moderate winds, and seas of 4-6 ft, N of 18N and W of the front. Gentle to moderate winds, and seas of 4-5 ft are noted over the Caribbean waters E of the front. For the forecast, high pressure will build SE across the western Atlantic through Fri. This will force the N portion of the front to drift SE across Hispaniola tonight before gradually dissipating Wed. Fresh to strong N winds behind the front will become N to NE tonight through Wed then veer NE Wed night through Thu night, with strongest winds in the lee of Cuba and through the Windward Passage. At the same time, fresh trades are expected in the south- central Caribbean, including the Gulf of Venezuela, increasing to strong each night. ...ATLANTIC OCEAN... Please read the Special Features section for information about the Gale Warning and Very Rough Seas. A stationary front enters the waters near 31N67W, and extends SW to the Windward Islands. Scattered moderate convection is noted within 240 nm east of the front. Strong to near gale force winds are N of 29N within 150 nm east of the front. A reinforcing front extends from 31N72W to central Florida. Moderate to fresh winds, and seas of 8-10 ft are west of this front. Moderate winds are noted between the fronts, with seas in the 8-11 ft range. Another stationary front enters the discussion waters near 31N37W to 26N57W. Gales north of this front are discussed above. Low pressure of 1011 mb is centered near 23N57W, with limited convection. Outside of the area of gale force winds, fresh to near gale winds are found N of 25N between 40W and 60W. Fresh to strong winds are noted from 20N to 25N and E of 27W. Gentle to moderate winds prevail elsewhere. Outside of the area of 12 ft seas discussed above, seas greater than 8 ft cover much of the discussion waters N of 18N and W of 20W. Seas in the 6-8 ft range are noted elsewhere. For the forecast W of 55W, strong high pressure will build into the western Atlantic behind the front through early Thu, causing the fresh to strong N winds to continue, before gradually diminishing to moderate to fresh Thu night and Fri. The front to move SE as a cold front and reach from 31N61W to central Hispaniola Wed evening, and from 22N60W to NW of Puerto Rico Thu evening. Winds and seas will slowly subside Fri night and Sat as high pressure weakens. $$ AL