645 AXNT20 KNHC 311739 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 UTC Tue Dec 31 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. ...SPECIAL FEATURES... Central Atlantic Significant Swell Event: A 991 mb low is centered north of the area near 37N40W. Strong winds cover the waters north of 22N east of 50W, with rough to very rough seas of 12 to 14 ft covering the waters north of 23N between 25W and 50W. The low pressure will move little over the next couple of days, and will support N swell of 12 to 14 ft north of 27N between 25W and 50W into Fri. For more details on the marine conditions, please refer to the latest NWS High Seas Forecast issued by the National Hurricane Center at the website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml ...MONSOON TROUGH/ITCZ... The monsoon trough remains inland over West Africa. The ITCZ extends from near 05N08W to 04N27W to 02N50W. Scattered moderate convection is noted along and within 100 nm of the ITCZ. ...GULF OF MEXICO... A cold front is entering the northwestern Gulf with moderate to fresh N winds behind the front. Meanwhile, a weak ridge extends from the western Atlantic to the west-central Gulf. Gentle to moderate S to SW winds are noted across the northwest Gulf, between the ridge and approaching cold front. Light to gentle breezes are noted elsewhere. Slight seas are also observed across the basin. For the forecast, a weakening cold front entering the northwestern Gulf of Mexico this morning will slowly progress southeastward across the basin through Wed before exiting the basin early Thu. Fresh to locally strong N to NE winds will occur behind the front off the coast of Texas this afternoon into early Thu, with fresh N winds developing across the northeastern Gulf tonight. Moderate to locally fresh NE to E winds will then cover much of the basin Wed into early Thu. Looking ahead, another cold front will enter the northwestern Gulf late Thu, and move southeastward through the basin into this weekend. Fresh to locally strong N to NE winds and moderate to locally rough seas will occur in the wake of the front. ...CARIBBEAN SEA... Scattered moderate convection is occurring in the SW Caribbean generally south of 17N and west of 76W, enhanced by the East Pacific monsoon trough entering the basin. Moderate to fresh E winds prevail in the central Caribbean with gentle to locally moderate E winds elsewhere. Seas are 3-6 ft in the central and eastern Caribbean, with seas of 1-4 ft across the rest of the basin. Large NE swell also persists in the northern Caribbean Passages. For the forecast, moderate to locally fresh trade winds and slight to moderate seas will occur across the basin through Wed. An increasing pressure gradient between ridging in the central Atlantic and a cold front moving southeastward through the Gulf of Mexico will lead to more widespread fresh NE winds across the Caribbean late Wed night through Fri morning. The cold front will enter the northwestern basin by early Thu and stall before dissipating Fri. Winds will pulse to strong speeds each night into Fri offshore of Colombia, through the Windward Passage, and downwind of Hispaniola and Cuba. Locally rough seas will be possible near strong winds. Looking ahead, fresh to strong NE winds will develop across the northwestern and north-central Caribbean on Sat ahead of a strong front moving through the western Atlantic and Gulf of Mexico. ...ATLANTIC OCEAN... Please see the Special Features section for details about the significant swell event in the central Atlantic. As described in the Special Features section, the main weather feature is the 991 mb low pressure southwest of the Azores. A cold front extends from near the low pressure to 20N40W, with a trough then extending to near 15N49W. Numerous showers and thunderstorms are active north of 23N between the front and 25W. In addition to the strong winds and rough to very rough seas over the central Atlantic, seas of 8 to 12 ft in N swell cover the waters north 15N between 26W and 55W. Elsewhere, fresh to strong E winds are occurring N of 17N between 25W and the west coast of Africa due to a strong pressure gradient between the low and high pressure over the NE Atlantic. The rest of the basin is dominated by ridging from both areas of high pressure in the NW and NE Atlantic, with gentle to moderate E winds and seas of 4-7 ft observed across much of the basin. For the forecast west of 55W, rough seas east of 60W generated by a strong storm system east of the area will slowly subside into this afternoon. Fresh SW winds will develop off the coast of Florida today ahead of a front moving off the east coast of the United States. Fresh to locally strong NW winds will occur behind the front tonight through Wed morning, generally north of 30N between 70W and 80W. The front will progress southeastward through Thu before weakening by late week. Looking ahead, a strong cold front will move off the coast of the southeastern United States on Fri, supporting strong to near gale-force winds and rough to very rough seas across most areas north of 27N into this weekend. $$ Adams