000 AXNT20 KNHC 211741 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 UTC Sat Dec 21 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 1200 UTC surface analysis and satellite imagery through 1800 UTC. ..MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 01N09E and extends to 02N01W. The ITCZ continues from 02N01W to 03N51W. Widely scattered moderate convection is observed from 03N to 07N between 24W and 41W. ...GULF OF MEXICO... High pressure over the central US extends a ridge into the Gulf of Mexico, supporting moderate to fresh N to NE winds across much of the Gulf. Seas across the basin are generally 3-6 ft. For the forecast, expect moderate N to NE winds over the remainder of the Gulf today as high pressure builds modestly into the basin behind a cold front moving into the northwestern Caribbean. This high pressure centered over the central United States this morning extends southward into the NW Gulf, and will drift slowly eastward through the middle of next week, resulting in moderate E to SE winds late Sun into next week. ...CARIBBEAN SEA... A cold front extends from central Cuba to the Yucatan Peninsula, but no significant convection is noted with this boundary. Farther east, divergence aloft supports scattered moderate convection in the north-central Caribbean north of 14N between 70W and 80W. Scattered moderate to strong convection is also noted in the SW Caribbean waters, impacting coastal portions of Costa Rica and Panama. Moderate to fresh E to NE winds and moderate seas are noted through the basin. For the forecast, moderate to locally fresh N to NE winds will prevail across the western half of the Caribbean through Sun as a series of weakening cold fronts drift southward across the SE Bahamas and dissipate this weekend. Elsewhere, moderate to locally fresh trades are expected over the central and eastern Caribbean. Slight to moderate seas will dominate the basin this weekend. High pressure will build over the eastern United States and western Atlantic early next week in the wake of multiple cold fronts moving off the east coast. A strengthening pressure gradient between these features will lead to fresh to locally strong NE to E winds across much of the Caribbean Sun night through Wed, particularly through the Windward Passage. ...ATLANTIC OCEAN... A cold front extends from a low pressure system off Nova Scotia to the NW and central Bahamas and into northern Cuba. A surface trough extends from 31N65W to just north of Hispaniola. Divergence aloft is sustaining scattered moderate convection east of the surface trough to about 63W. Fresh to strong W-NW winds and seas of 6-9 ft are occurring behind the frontal boundary and north of the Bahamas. Meanwhile, fresh to locally strong SE-S winds are noted between 55W and 62W. Seas in the area described are also 6-9 ft. Elsewhere in the SW North Atlantic (west of 55W), moderate or weaker winds and moderate seas are prevalent. Farther east, a 1013 mb low pressure system centered near 32N43W extends a stationary front southward from a triple point axis near 38N43W, with the front then running from 38N43W to 30N37W to 18N52W. Scattered showers and isolated thunderstorms are found ahead of the frontal boundary to 28W and north of 23N. The pressure gradient between a 1043 mb high just north of the Azores and the aforementioned low, front and lower pressures in the deep tropics result in fresh to strong NE-E winds east of 40W and north of 20N. Seas in these waters are moderate to rough, peaking near 10 ft off Morocco. Moderate or weaker winds and moderate seas are prevalent elsewhere. For the forecast W of 55W, a cold front extends from 31N68W to the central Bahamas this morning, and will progress slowly eastward through early next week. Fresh NW winds and building seas will occur behind the front north of 27.5N and west of 68W through midday. Farther east, a broad ridge will drift eastward, leading to fresh S to SE winds along the periphery of the ridge, generally north of 20N and east of 65W through this evening. South of 20N, moderate to briefly fresh trades will prevail into the middle of next week. Looking ahead, widespread fresh to locally strong NE winds and rough seas will redevelop north of 20N by early Mon as strong high pressure builds across the western Atlantic and into the local region, behind the next cold front. $$ Adams