000 AXNT20 KNHC 190425 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Thu Dec 19 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 0000 UTC surface analysis and satellite imagery through 0355 UTC. ..MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through the coast of Liberia near 06N10W and extends westward to 05N19W. The ITCZ stretches from 05N19W to 04N35W to NE Brazil near 00N50W. Scattered moderate convection is observed from 03N to 05N and between 30W and 40W. ...GULF OF MEXICO... A cold front is moving across the NW Gulf of Mexico, extending from south-central Louisiana to southern Texas. No significant convection is noted with this boundary. A few showers are evident in the central Gulf along a weak surface trough, while generally dry conditions prevail elsewhere. A recent scatterometer satellite pass and surface observations indicate that fresh northerly winds are found behind the frontal boundary. Seas in these waters are 3-5 ft. Fresh northerly winds are also found in the SW Gulf waters, especially south of 25N and west of 90W, along with seas of 3-5 ft. Elsewhere, moderate or weaker winds and slight seas are prevalent. For the forecast, the aforementioned front entering the northwestern Gulf of Mexico will progress southeastward overnight before dissipating on Thu. Fresh to locally strong N to NE winds will occur along and behind the front. Elsewhere, moderate N winds will prevail through Thu to the west of a trough extending from 28N89W into the Yucatan Peninsula. Another strong cold front will enter the northern Gulf of Mexico Fri night and progress southward through the weekend before dissipating late Sun. Fresh to locally strong N winds and a modest increase seas will occur along and behind this front Fri night in the northern Gulf. Moderate NE winds will then occur across the basin on Sat. Looking ahead, building high pressure will shift slowly eastward across the eastern United States late Sat through Mon, leading to moderate to locally fresh NE to E winds across most of the basin into early next week. ...CARIBBEAN SEA... A surface trough over the Yucatan peninsula and divergence aloft result in scattered showers and isolated thunderstorms off Yucatan and in the Gulf of Honduras. A few showers are also seen near the Dominican Republic. Elsewhere, much drier conditions prevail. A broad subtropical ridge over the central Atlantic extends in the Caribbean Sea, forcing fresh to strong over much of the central and eastern portions of the basin. The strongest winds are found in the south-central Caribbean, off NW Colombia. Seas in these waters are 7-10 ft, with the highest seas occurring in the water passages of the Leeward Islands. In the rest of the Caribbean, moderate or weaker winds and slight to moderate seas are prevalent. For the forecast, fresh trade winds will continue across the eastern, central and southwestern Caribbean as well as through the Atlantic Passages through Fri as a strong pressure gradient between high pressure in the northern Atlantic and the Colombian low prevails. Winds will pulse to strong speeds offshore of Colombia and Venezuela tonight and again Thu night. Seas of 4 to 7 ft will prevail over the aforementioned areas, with locally rough seas of 8 to 9 ft occurring near strong winds in the south-central Caribbean. Elsewhere, gentle to moderate NE winds and seas of 2 to 4 ft are expected in the northwestern basin through Thu. Looking ahead, high pressure building over the Gulf of Mexico this weekend will lead to generally moderate to locally fresh E to NE winds across the basin through the weekend. ...ATLANTIC OCEAN... A few showers and isolated thunderstorms are noted north of the NW Bahamas due to divergence aloft. The remainder of the SW North Atlantic, west of 55W, is dominated by a strong subtropical ridge over the central Atlantic. A recent scatterometer satellite pass captured fresh to strong easterly winds over much of the basin, especially between 55W and 77W. Rough seas are occurring in the area described, peaking around 13 ft near 22N62W. Farther east, a 1021 mb low pressure system is centered near 30N38W and a cold front extends south from this low to 19N42W. Scattered showers and isolated thunderstorms are evident ahead of the frontal boundary to within 120 nm. Strong to locally near gale-force winds are noted on satellite-derived wind data north of 29N and between 34W and 40W. Gale-force wind gusts are likely occurring with the strongest convection. Mariners should use caution. The rest of the central and eastern Atlantic are under the influence of the aforementioned subtropical ridge. Fresh to locally strong NE-E winds are present north of 20N and east of 55W. Rough seas are noted in these waters. Mainly fresh NE-E winds and moderate to rough seas are observed south of 20N and west of 50W. Elsewhere, moderate or weaker winds and moderate seas are prevalent. For the forecast W of 55W, a wide swath of fresh NE to SE winds will occur through Thu for areas north of 15N and west of 55W as a tight pressure gradient prevails between high pressure in the central Atlantic, a decaying cold front in the tropical Atlantic and the Colombian low. Strong E to NE winds will occur tonight through Thu morning from 18N to 27N east of 67W. Very rough seas of 12 to 13 ft will occur near the area of strongest winds. Rough seas in excess of 8 ft will prevail north of 15N through the end of the work week before seas begin to slowly subside from north to south late Thu through early Sat. South of 15N, moderate to locally fresh trades and rough seas will prevail through Thu before winds diminish to moderate speeds on Fri. A cold front will move off the coast of the southeastern United States late Thu and stall, then enter the NW zones off of Florida Fri, and reach from 31N71W to western Cuba by Sat morning. Fresh to strong N to NW winds will occur behind the front. Looking ahead, widespread fresh to locally strong NE winds and rough seas will redevelop across areas north of 20N early next week. $$ Delgado