000 AXNT20 KNHC 200525 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0505 UTC. ..SPECIAL FEATURES... Central Atlantic Significant Swell Event: A surface trough stretches from 17N55W to 26N60W. Meanwhile, a robust high pressure system of 1053 mb is positioned near 47N31W. The pressure gradient between these features is supporting fresh to near gale-force easterly winds north of 25N and between 41W and 61W. Seas of 12-20 ft are present north of 21N and between 30W and 65W. The highest seas are occurring near 31N54W. The ridge will slide eastward and weaken in the next couple of days, allowing the winds to diminish and seas to subside, decreasing below 12 ft Thu. 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 enters the Atlantic through the coast of Liberia near 07N11W and continues to 05N14W. The ITCZ stretches from 05N14W to 02N33W to 03N51W. No deep convection is noted near the ITCZ. ...GULF OF MEXICO... An expansive 1032 mb high pressure system over the eastern United States extends southwestward, encompassing the Gulf of Mexico. No deep convection is noted across the basin. Fresh to strong NE winds are found in the SE Gulf and Florida Straits. Seas in these waters are 5-7 ft. Moderate to locally fresh easterly winds and seas of 4-7 ft are prevalent in the remainder of the eastern Gulf, east of 90W. Moderate or weaker winds and 2-4 ft seas prevail elsewhere. For the forecast, a broad ridge centered over the Ohio Valley extends SE into the western Atlantic, behind a stalling cold front across the central Caribbean. This pattern will support moderate to fresh NE winds over the E Gulf tonight. The high pressure will shift eastward into the eastern U.S. through Thu, causing fresh winds to veer E, with strong winds developing in the Florida Straits and adjacent waters through Fri. SE return flow is expected to develop Sat through Sun. ...CARIBBEAN SEA... A stationary front extends from Haiti to the Panama and Colombia border near 8.5N77W. A few showers are noted near this boundary. The pressure gradient between the strong ridge well north of the islands and the frontal boundary result in fresh to strong northerly winds in the waters west of the front. Seas in these waters are 7-10 ft south of 18N and 4-7 ft elsewhere. Gentle to light winds and moderate seas are prevalent in the rest of the Caribbean Sea. 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 through Wed night before gradually dissipating. 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, pulsing to strong each night. ...ATLANTIC OCEAN... Please read the Special Features section for information about the Significant Swell event in the north-central Atlantic. A stationary front remains draped across the southwestern tropical Atlantic, extending from 31N67W to the Turks and Caicos Islands and then to Hispaniola. Scattered moderate to isolated strong convection is evident north of 26N and between the frontal boundary and 62W. The pressure gradient between the a strong ridge over the eastern United States and the stationary front sustain fresh to strong northerly winds, primarily west of the front. Seas in these waters are 8-13 ft. The highest seas are found near 31N69W. Divergence aloft is supporting isolated to scattered showers and isolated thunderstorms from 15N to 26N and between 37W and 51W. The remainder of the tropical Atlantic is dominated by broad ridging. The weak low pressure system in the central Atlantic has weakened into a surface trough that extends from 17N55W to 26N60W. The pressure gradient between the 1053 mb high pressure near 47N31W and lower pressures associated with the aforementioned trough sustain fresh to near gale-force easterly winds north of 25N and between 41W and 61W. This is supporting the very rough seas discussed in the Special Features section. Farther east, fresh to strong easterly winds and seas of 8-12 ft are present east of 35W. Moderate or weaker winds and moderate seas prevail elsewhere. For the forecast W of 55W, strong high pressure will build into the western Atlantic behind the SW tropical Atlantic 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 will move SE and reach from 31N61W to central Hispaniola Wed evening, from 28N55W to the N Mona Passage Thu evening, then gradually dissipate. Winds and seas will slowly subside Fri night and Sat as high pressure weakens.. $$ Delgado