000 AXNT20 KNHC 211011 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Thu Dec 21 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... Atlantic Ocean Significant Swell Event: A cold front extends from 31N61W to Hispaniola. A 1032 mb high pressure is present in the eastern United States and a 1047 mb high pressure is centered near 45N25W. The strong pressure gradient due to these systems result in fresh to strong northerly winds west of the front and fresh to strong southerly winds east of the front to 45W and north of 25N. Rough to very rough seas prevail in these waters, peaking around 14 ft near 30N65W. The ridge will slide eastward and weaken during the next few days. The wind speeds will decrease and the sea heights will subside to less than 12 ft by Fri. Please read the latest NWS High Seas Forecasts, and the Offshore Waters Forecasts, that are issued by the National Hurricane Center, at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and www.nhc.noaa.gov/marine/offshores.php, for more details about the Very Rough Seas. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Nigeria near 04N06W and extends to 03N15W. The ITCZ extends from 03N15W to 01N50W. A few showers are observed near the ITCZ between 25W and 35W. ...GULF OF MEXICO... A scatterometer satellite pass from a few hours ago confirmed fresh to strong NE to E winds across the southeast Gulf. This pattern is being supported by strong 1032 mb high pressure centered over the southeast United States. Seas are estimated to be 6 to 8 ft in this area, just off northwest Cuba. Moderate E to SE winds and 4 to 6 ft seas are evident elsewhere. For the forecast, winds and seas will diminish through early next week as the high pressure shifts east, ahead of an approaching cold front. The cold front will move off the Texas coast Sun night, and reach from near Apalachicola, Florida to near Poza Rica, Mexico by Mon night. ...CARIBBEAN SEA... A stationary front stretches from southern Hispaniola near the border of Haiti and the Dominican Republic to near 15N78W, where it continues as a dissipate stationary front to near El Porvenir in eastern Panama. Recent scatterometer satellite data indicate a plume of fresh to strong NE winds across the Windward Passage. Fresh NE winds are also evident off the southern coast of Cuba, and off Colombia. Seas are likely 6 to 9 ft in these areas. Moderate NE winds and 4 to 6 ft seas are evident elsewhere. For the forecast, the aforementioned front will dissipate today. Building high pressure north of the area will bring a return to more typical E trade winds Fri through early next week. ...ATLANTIC OCEAN... Please, read the SPECIAL FEATURES section above for details about the Central Atlantic Ocean Significant Swell Event. A cold front extends from 31N60W and continues southwestward to north-central Dominican Republic. A pre-frontal trough is evident ahead of the front, anchored by a 1007 mb low pressure system near 24N58W. An associated upper trough moving across the same area is supporting scattered showers and isolated thunderstorms from 24N to 27N and between 55W and 57W. More information on these features can be found in the Special Features section. The rest of the Atlantic is dominated by broad ridging. The pressure gradient between the 1047 mb high pressure system near 45N25W and lower pressures in the deep tropics result in fresh to locally near gale-force easterly winds east of 40W, as noted in an earlier scatterometer satellite pass. A recent Altika altimeter satellite pass confirmed combined seas of 8 to 12 ft over the eastern Atlantic. For the forecast for waters west of 55W, the aforementioned front will shift east of region by late Fri, except for the southern portion of the front stalling across the northern Leeward Islands. Fresh to strong N to NE winds following the front will diminish through tonight. Northerly swell will linger into Sun. Looking ahead, winds and seas will increase Sun night and Mon from the central Bahamas to northeast Florida ahead of a cold front approaching from the west. $$ Christensen