000 AXNT20 KNHC 161045 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1215 UTC Mon Dec 16 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. ...SPECIAL FEATURES... Western Atlantic Significant Swell Event: Large NE swell generated by earlier strong gale winds across the northern Atlantic is persisting across the western Atlantic. It is sustaining seas of 12 to 16 ft north of 24N between 64W and the Bahamas, and also north of 27N between 78W and the Florida coast. Fresh to strong NE to E winds are occurring over this area. The swell will slowly decay today allowing for seas to subside below 12 ft by this evening per the latest wave model guidance. Please refer to the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFAT2.html and https://www.nhc.noaa.gov/marine/offshores.php for more detail. Eastern Atlantic Gale Warning: Meteo-France has issued Gale Warnings for their Marine Zones: IRVING, MADEIRA AND CANARIAS through 16/18Z. Please refer to the website: https://www.wwmiws.wmo.int/index.php/metareas/affiche/2 for more information. ...MONSOON TROUGH/ITCZ... The monsoon trough axis is mostly over Africa. The ITCZ extends west-southwestward from off the Sierra Leone coast at 06N14W through 05N30W to 04N40W and to near 02N47W. Numerous moderate to strong convection is seen within 60 nm of the ITCZ between 25W and 34W. Scattered moderate convection is within 60 nm north of the ITCZ between 34W and 40W ,and within 60 nm south of the ITCZ between 42W and 45W. ...GULF OF MEXICO... High pressure ridging stretches southwestward from the eastern United States to the eastern and central sections of the basin. The resultant gradient is allowing for fresh to strong NE to E winds along with seas of 6 to 9 ft to exist over the southeastern and east-central Gulf sections, including the Straits of Florida and Yucatan Channel. Generally, moderate E to SE winds are elsewhere, except for moderate to fresh NE to E winds over the NE part of the basin. Seas are 4 to 6 ft elsewhere, except for higher seas of 6 to 8 ft over the central part of the Gulf from 22N to 26N between 87W and 91W. For the forecast, the aforementioned high pressure will continue to support fresh to strong NE to E winds and moderate to rough seas over the eastern Gulf, including the Straits of Florida through Mon. Then, gentle to moderate winds and slight to moderate seas are expected through Wed. Looking ahead, a weak cold front will reach the northwestern Gulf by Wed night and dissipate over the northern Gulf by early Thu. High pressure in the wake of the front will bring gentle to moderate northerly winds and slight to moderate seas Thu through Sat. ...CARIBBEAN SEA... A trough is analyzed from near the southeastern Bahamas to low pressure of 1011 mb near the eastern tip of Cuba and continues to 15N77W. Scattered showers and thunderstorms with frequent lightning continue in the Windward Passage area, and also over the waters near Jamaica and the southwest part of Haiti. Convergent trade winds are causing isolated thunderstorms across the eastern basin, including waters near Puerto Rico and the Virgin Islands. Fresh to strong NE winds along with seas of of 5 to 7 ft are over the northwestern Caribbean. Gentle to moderate NE to E winds, with seas of 3 to 5 ft seas prevail elsewhere in the Caribbean Sea. Isolated showers and thunderstorms are moving westward are over the northwestern Caribbean near the Yucatan Channel. For the forecast, a strong pressure gradient will continue to induce fresh to strong NE winds in the lee of Cuba, and over the NW Caribbean through this morning. A trough that extends from near the southeastern Bahamas to the eastern tip of Cuba and to near 15N77W will drift westward across the central Caribbean through Tue, likely reaching the NW Caribbean on Wed. High pressure will build in the wake on the trough, and will enhance the trades to fresh to strong speeds over the central Caribbean mainly at night Mon through Thu. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section above for information on significant swell event. A trough extends from the Caribbean, from southeast of Jamaica near 15N77W northeastward to low pressure of 1011 mb near the eastern tip of Cuba, and continues northeastward to near 26N71W. Another trough is along a position from near 25N61W to 19N64W. Scattered showers and isolated thunderstorms are noted from 19N to 25N between 58W and 71W. Gentle to moderate E to SE winds along with seas of 7 to 10 ft in moderate to large mixed swell are noted from 20N to 24N between 55W and the Bahamas. In the central Atlantic, gentle N to NE to E winds and 8 to 11 ft seas in large northerly swell are found north of 20N between 35W and 64W. In the Tropical Atlantic from 04N to 20N between 35W and the Lesser Antilles, gentle to moderate NE to ENE winds under relatively weak high pressure along with seas of 5 to 8 ft in mixed moderate swell are present there. Gentle to moderate SE winds and seas of 4 to 6 ft in mixed moderate swell remain for the rest of the Atlantic Basin. For the forecast W of 55W, the tight pressure gradient between strong high pressure over the eastern U.S. Seaboard and the aforementioned 1011 mb low/surface trough will continue to support fresh to strong NE winds and very rough seas over most of the waters west of 65W. These conditions will slowly abate today into early this evening. Fresh to locally strong E winds will prevail E of the Bahamas through Wed as a ridge builds towards the western Atlantic. Looking ahead, the next cold front is forecast to move off the northeastern Florida coast Wed night, reach from near 32N71W to the central Bahamas by late Thu night and stall. A strong cold front may quickly merge with the stalled front late on Fri, followed by fresh to strong NW winds. $$ Aguirre