054 AXNT20 KNHC 190459 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Tue Dec 19 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 0000 UTC surface analysis and satellite imagery through 0455 UTC. ..SPECIAL FEATURES... Western Atlantic Gale Warning: A stationary cold front enters the basin near 31N69W and continues southwestward to the Windward Islands. A band of showers and thunderstorms persists along and ahead of the cold front to 65W. A 1050 mb high pressure system near 45N43W extends southwestward to the NE Caribbean. The pressure gradient between these features is supporting near-gale to gale force winds N of 26W and between 61W and the front. Seas are peaking near 16 ft in this area, with seas in excess of 12 ft covering the waters N of 25N between 60W and 73W. The front is forecast to reach from 31N69W to Haiti Tue morning, and from near Bermuda to the N coast of Hispaniola near 20N70W by Wed morning. Strong high pressure will build into the western Atlantic behind the front Tue night through early Thu to produce fresh to strong winds, gradually diminishing to moderate to fresh Thu through Fri. Central Atlantic Gale Warning: The pressure gradient between the aforementioned 1050 mb high centered near 45N43W and a 1011 mb low pressure center near 23N48W is supporting a large area of near-gale to gale force winds N of 24N between 43W and 57W. Seas over this area are peaking near 22 ft. Seas greater than 12 ft cover the waters N of 20N and between 38W and 60W. Numerous moderate to isolated strong convection is present from 14N to 24N and between 40W and 46W. The low will move westward, while the high center moves eastward over the next couple of days. This will loosen the pressure gradient, and diminish winds below gale force by the middle of the week. 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 both Gale Warnings. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic through the coast of Liberia near 05N09W and continues westward to 03N14W. The ITCZ extends from 03N14W to 03N33W and to 01N50W. Numerous moderate to isolated strong convection is observed from the ITCZ to 11N and between 21W and 35W. ...GULF OF MEXICO... A 1023 mb high pressure system positioned near the southern Texas coast allows for dry, continental air to filter across the Gulf of Mexico. No deep convection is noted in the basin. A recent scatterometer satellite pass captured moderate to fresh northerly winds over the eastern half of the Gulf of Mexico. Seas in these waters are 4-7 ft. Elsewhere, light to gentle winds and slight to moderate seas prevail. For the forecast, the aforementioned weather pattern will support fresh N winds over the E Gulf tonight. Stronger high pressure will shift eastward across the central U.S. and into the eastern U.S. Tue through Thu, to produce fresh to strong NE to E winds across the eastern Gulf, including the Straits of Florida, through early Fri. ...CARIBBEAN SEA... A stationary front extends from the entrance of the Windward Passage to near 13N77W. A few showers are seen on satellite imagery near this boundary, especially affecting SW Haiti. No deep convection is evident in the remainder of the Caribbean Sea. The pressure gradient between the aforementioned front and the ridge over the Gulf of Mexico sustain fresh to strong northerly winds west of 77W. The strongest winds are found within 90 nm of the coast of Nicaragua and NE Honduras. Seas are 7-10 ft south of 18N and between 77W and 85W and 4-7 ft in the rest of the Caribbean waters west of 77W. The highest seas are found in the SW Caribbean near 11N81W. In the remainder of the basin, moderate or weaker winds and moderate seas are prevalent. For the forecast, the front will remain nearly stationary on Tue, then drift SE across Hispaniola Wed before gradually dissipating late Wed. Fresh to strong winds behind this front will become N to NE Tue night through Wed night. High pressure will build SE across the western Atlantic Wed night through Fri to produce a broad area of fresh to strong NE winds in the lee of Cuba and the Windward Passage. At the same time, fresh to locally strong trades are expected in the south- central Caribbean, including the Gulf of Venezuela, mainly at night. ...ATLANTIC OCEAN... Please read the Special Features section for more on the ongoing Gale Warnings. Aside from the areas in the Special Features section, the pressure gradient between the ridge over the Gulf of Mexico and the frontal system off the eastern United States sustain fresh to strong NW winds north of 27N and west of 75W. Moderate or weaker winds are found in the remaining waters west of 70W. Aside from the 12 ft or greater seas west of 70W, 8-12 ft are prevalent north of the Bahamas and east of Florida. Aside from the area of gale force winds, fresh to near gale force winds are N of 20N and between 35W and 70W. Farther east, fresh to strong easterly winds are evident east of 33W and north of 13N. Moderate or weaker winds are present elsewhere in the basin. Aside from the area of 12 ft seas, seas greater than 8 ft cover the waters N of 18N and W of 35W. Seas of 8-11 ft are N of 20N and E of 35W. Elsewhere, seas of 5-8 ft prevail. For the forecast W of 55W, a western Atlantic cold front extends through 31N69W to the Windward Passage. SE to S gale-force winds are ahead of the front N of 26N and E of front to 66W, and will diminish below gale-force after midnight. Behind the front, fresh to strong W winds are noted N of 30N. A band of showers and thunderstorms persists along and ahead of the cold front to 65W. The front is forecast to reach from 31N69W to Haiti Tue morning, and from near Bermuda to the N coast of Hispaniola near 20N70W by Wed morning. Strong high pressure will build into the western Atlantic behind the front Tue night through early Thu to produce fresh to strong winds, gradually diminishing to moderate to fresh Thu through Fri. $$ Delgado