000 AXNT20 KNHC 181041 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1215 UTC Wed Dec 18 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 0600 UTC surface analysis and satellite imagery through 1030 UTC. ..MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near 07N12W and extends to 05N18W. The ITCZ continues from 05N18W to 06N51W. Scattered moderate convection is occurring from 02N to 05N between 25W to 32W and from 05N to 07N between 43W and 54W. ...GULF OF MEXICO... A surface trough extends from 28N89W southward through the Yucatan Peninsula into the northwestern Caribbean, and isolated showers and thunderstorms are occurring near the trough axis. Moderate to locally fresh E winds are noted to the east of this trough. A second trough extends from the Big Bend of Florida to 27N83W, with no significant convection surrounding this trough. Elsewhere, gentle to moderate E to SE winds prevail. For the forecast, moderate to locally fresh E winds will occur this morning to the east of a trough in the central Gulf. Winds will diminish through this morning, and gentle to moderate winds will prevail across the basin through this afternoon. A cold front will move into the northwestern Gulf of Mexico this evening, and fresh to locally strong N winds will occur along and behind the front. The front will dissipate Thu morning over the central basin. High pressure will build over the central United States on Fri, leading to moderate N to NE winds across the Gulf. Looking ahead, gentle to moderate E winds and slight to moderate seas are anticipated for this weekend. ...CARIBBEAN SEA... A surface trough extends from the central Gulf of Mexico southeastward to 17N86W in the northwestern Caribbean. Scattered moderate convection is noted surrounding the southern portion of the trough, from 18N to 21W west of 85W. Elsewhere, the tight pressure gradient between high pressure in the central Atlantic and building low pressure over Colombia is leading to fresh trades over the central, eastern and southwestern Caribbean. Locally strong NE winds are occurring off the coast of Colombia, and locally rough seas of 8 to 9 ft are likely in this area. Gentle to moderate NE to E winds and 2 to 4 ft seas are noted in the northwestern basin, and waters near Costa Rica and Panama. Moderate to fresh E winds and seas of 4 to 6 ft prevail elsewhere in the Caribbean Sea. For the forecast, moderate to fresh trade winds will persist over the central, eastern and southwestern Caribbean through Fri morning. Winds will pulse to strong speeds each night off the coast of Colombia and Venezuela. Strong NE winds are also expected downwind of Hispaniola and through the Atlantic Passages into early Thu. Seas of 4 to 7 ft will prevail across the aforementioned areas, with locally rough seas prompted by strong winds off the coast of Colombia through late this week. A long period NE swell will produce rough seas through the Atlantic Passages through Fri before seas diminish. Elsewhere, gentle to locally moderate NE winds and seas of 3 to 5 ft are expected in the northwestern Caribbean through Fri. Looking ahead, building high pressure over eastern Mexico will lead to generally moderate to locally fresh E to NE winds across the basin this weekend. ...ATLANTIC OCEAN... A cold front extends from 31N28W to 23N56W. Fresh to locally strong NE to E winds are occurring to the north of this front. Locally very rough seas to 12 ft are occurring near the western portion of the front. Elsewhere, fresh with locally strong NE to ENE winds and 8 to 11 ft seas are present north of 20N between 50W and the Florida coast/Bahamas. South of 20N, moderate to locally fresh trades and seas of 6 to 8 ft prevail. For the forecast W of 55W, the strong pressure gradient between high pressure in the central Atlantic and troughing over western Florida and the Gulf of Mexico will continue to support fresh E winds across areas north of the Greater Antilles today, with strong winds anticipated over the southeastern Bahamas. Farther east, a cold front analyzed from 31N28W to 23N56W will progress slowly southwestward through Thu, producing widespread fresh E winds both ahead and behind the front, with strong winds occurring along the front. Rough seas associated with these features will occur 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. Very rough seas in excess of 12 ft will be possible along and behind the aforementioned cold front. Elsewhere, fresh trade winds and rough seas will prevail south of 15N through Thu before winds diminish to moderate speeds on Fri. A cold front will move off the coast of the southeastern United States late tonight into Thu and extend from near 31N74W to SE Florida Fri morning, and from 31N67W to eastern Cuba by Sat morning. Fresh to locally strong N to NW winds will occur behind the front. $$ ADAMS