325 AXNT20 KNHC 161802 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 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 1200 UTC surface analysis and satellite imagery through 1740 UTC. ...SPECIAL FEATURES... ...WESTERN ATLANTIC OCEAN SIGNIFICANT SWELL EVENT... Large NE swell is persisting in the western Atlantic Ocean. The swell has been generated by earlier northern Atlantic Ocean gale-force winds. Rough to very rough seas have been from 24N northward between 64W and the Bahamas, and from 27N northward between 78W and the Florida coast. Strong NE winds are in this area. The swell will decay slowly today. The sea heights will subside, to less than 12 feet, by this evening, per the latest wave model guidance. Rough seas, in general, are elsewhere from 20N northward from 50W westward. An Atlantic Ocean surface trough is from SE Cuba to 26N between 73W and 74W. Expect for the next 24 hours or so: strong to near gale-force NE to N winds, and rough to very roughs seas, from 23N northward between 70W and the Bahamas. Strong NE to E winds, and rough seas in NE swell, from 22N northward between 60W and 70W. Fresh or slower winds, and rough seas, are elsewhere from 21N northward from 60W westward. Precipitation: scattered moderate to isolated strong is from 24N to 28N between 70W and 75W. Please, refer to the latest High Seas Forecast, and the latest Offshore Waters Forecast, that are issued by the National Hurricane Center, at the website: https://www.nhc.noaa.gov/text/MIAHSFAT2.html, and https://www.nhc.noaa.gov/marine/offshores.php, for details. ...METEO-FRANCE MARINE ZONES GALE-FORCE WIND WARNING FROM 35W EASTWARD... The METEO-FRANCE marine forecast consists of gale-force winds that will be slowing down in the western half of the marine zone MADEIRA, to less than gale-force, during the afternoon hours of today. A surface trough is along 31N26W 28N30W 26N36W. Rough to very rough seas, in general, are from 17N northward between 31N14W 27N20W 17N28W and 17N48W 31N58W. Strong SE winds are from 27N to 30N from 20W eastward. Strong and faster southerly winds are elsewhere from 30N northward between 15W and 31N26W 34N23W cold front. Please, refer to the Meteo-France High Seas Warning/Forecast, at the website: https://wwmiws.wmo.int, for details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the Prime Meridian along 05N, to 06N14W. The ITCZ continues from 06N14W, to 05N25W 03N35W, to the coast of Brazil close to 02N51W. Precipitation: scattered moderate to isolated strong is from 01N to 08N between 22W and 53W. ...GULF OF MEXICO... Broad surface anticyclonic wind flow covers the entire area. Strong NE winds, and rough seas, are from 26N southward from 88W eastward. The forecast is for those strong winds to slow down to fresh or slower winds in about 12 hours or so. Moderate to fresh surface anticyclonic wind flow, and slight to moderate seas, are in the remainder of the Gulf of Mexico. Strong high pressure over the eastern United States 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 today, thereafter, gentle to moderate winds and slight to moderate seas are expected through Wed. Looking ahead, a weak cold front will reach the NW Gulf of Mexico 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... An Atlantic Ocean surface trough passes through SE Cuba, to NW Jamaica, to 17N80W. A second and a separate NW to SE oriented surface trough is along the coast of Honduras that is between 85W and 86W, to the coast of the Yucatan Peninsula close to 20N87W. Strong NE winds are from 19N northward between 80W and 87W. Rough seas are from 20N northward from 85W westward including in the Yucatan Channel. The wind speeds are forecast to be fresh or slower in about 12 hours or so. Fresh NE winds are elsewhere from 16N80W 18N85W 20N87W northward from 80W westward. Moderate NE winds are from 70W eastward, and from 13N northward between 70W and 80W. Moderate to fresh NE to E winds are from 13N southward between 70W and 80W. Moderate seas are elsewhere from Honduras northward from 80W westward. Slight to moderate seas are in the remainder of the Caribbean Sea. The monsoon trough is along 08.5N to 10N, between 74W in Colombia, and beyond southern Costa Rica, and into the Pacific Ocean. The 24-hour rainfall totals in inches, for the period that ended at 16/1200 UTC, are: 1.85 in Guadeloupe; 0.26 in San Juan in Puerto Rico; and 0.04 in Trinidad. This information is from the Pan American Temperature and Precipitation Tables/MIATPTPAN. 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 16N80W will drift westward across the central Caribbean today, likely reaching the NW Caribbean on Tue. 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 through Thu. ...ATLANTIC OCEAN... Please, read the SPECIAL FEATURES section, for details about the western Atlantic Ocean Significant Swell Event. Please, read the SPECIAL FEATURES section, also, for information about the METEO- FRANCE marine zone MADEIRA. The METEO-FRANCE marine forecast consists of gale-force winds, slowing down in the western half of the marine zone MADEIRA, to less than gale-force, during the afternoon hours of today. The 24-hour rainfall totals in inches, for the period that ended at 16/1200 UTC, are: 0.05 in Nassau in the Bahamas; and 0.03 in Freeport in the Bahamas. This information is from the Pan American Temperature and Precipitation Tables/ MIATPTPAN. A cold front passes through 31N46W, to 30N50W and 30N57W. Strong to near gale-force NE winds, and rough to very rough seas, are from 29N north between 50W and 60W. Fresh or slower winds, and rough seas in N to NE swell, are elsewhere from 16N northward and to the east of 48W and within 90 nm to the southeast of the cold front. Moderate to fresh winds cover much of the rest of the Atlantic Ocean. Moderate seas are in the remainder of the Atlantic Ocean. A tight pressure gradient between strong high pressure over the eastern Seaboard and a trough along 73W that crosses the SE Bahamas and the eastern tip of Cuba 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. $$ mt/gr