000 AXNT20 KNHC 170628 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Tue Dec 17 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 0500 UTC. ...SPECIAL FEATURES... Western Atlantic Significant Swell Event: Residual NE swell persists across the central Atlantic. It is sustaining seas of 12 to 14 ft north of 27N between 44W and 60W. Fresh to strong NE to ENE winds are occurring over this area. The swell will slowly decay tonight and Tuesday, allowing for seas to subside below 12 ft by Tue evening. 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. ...MONSOON TROUGH/ITCZ... A monsoon trough stays mostly over the Africa Continent. An ITCZ extends westward from 06N16W through 03N35W to 05N48W. Widely scattered moderate convection is found up to 50 nm along either side the ITCZ. ...GULF OF MEXICO... A surface trough over northern and central Florida is triggering scattered showers and isolated strong thunderstorms over southern Florida and the Florida Straits. Otherwise, a surface ridge runs southwestward from a 1028 mb high over northern Georgia to just south of Tampico, Mexico. Gentle ENE to SE winds and seas of 3 to 5 ft are present at the western Gulf, west of 94W. Moderate to fresh NE to ESE winds and 4 to 7 ft seas prevail for the rest of the Gulf. For the forecast, moderate to fresh E to NE winds will prevail through early Wed in the central and eastern Gulf, with moderate to locally fresh SE winds occurring in the western Gulf. Thereafter, gentle to moderate winds and slight to moderate seas are expected through Wed afternoon. Looking ahead, a weak cold front will enter the northwestern Gulf Wed evening, and fresh to strong N to NW winds will occur along and behind the front. The front will weaken and dissipate over the central Gulf by early Thu. Building high pressure over the south-central United States will lead to moderate N to NE winds and slight to moderate seas across the Gulf Thu through Sat. ...CARIBBEAN SEA... A surface trough curves southwestward from the southeast Bahama across eastern Cuba to offshore from the coastal border of Honduras and Nicaragua. Widely scattered showers and isolated thunderstorms are occurring over the Windward Passage and northwestern basin, including the Gulf of Honduras. Moderate to fresh NE to E winds and seas at 4 to 7 ft are found at the northwestern and central basin, including the Windward Passage and waters near the ABC Islands. Gentle NE to E winds and 3 to 5 ft seas prevail elsewhere in the Caribbean Sea. For the forecast, a strong pressure gradient between high pressure over the northwestern Atlantic and the aforementioned surface trough will continue to support moderate to locally fresh NE winds across the northwestern basin through Tue morning before winds diminish. As this same trough slowly progresses northwestward through midweek, a low pressure will strengthen over northwestern Colombia. In response, moderate to fresh trade winds will develop over the central and eastern Caribbean by early Tue and continue through Fri. Strong NE winds will occur at times off the coast of Colombia and Venezuela, through the Mona, Windward and Atlantic Passages and in the lee of Hispaniola and Puerto Rico, with the strongest winds occurring at night. Locally rough seas will develop in areas of strong wind. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section above for information on the significant swell event. A cold front curves westward from near the Azores across 31N38W to 28N56W, then continues northwestward as a stationary front to 31N62W. Scattered showers are occurring up to 60 nm north, and 100 nm south of this boundary. Convergent trades are triggering scattered showers and isolated thunderstorms just east of the Lesser Antilles. The northeastern end of a surface trough is causing similar conditions from the southeast Bahamas northward to near 25N. Refer to the Monsoon Trough/ITCZ section for additional convection in the Atlantic Basin. For the western Atlantic including the Bahamas, fresh to strong ENE to E winds and seas of 8 to 10 ft are present north of 20N between 60W and the Georgia/Florida coast. For the central Atlantic south of the Large NE Swell, gentle to moderate ENE to E winds and seas at 8 to 9 ft are evident from 20N to 27N between 35W and 60W. In the Tropical Atlantic from 04N to 20N between 35W and the Lesser Antilles, moderate with locally fresh NE to E winds and 8 to 9 ft seas exist. Gentle to moderate SE winds and seas of 6 to 8 ft in mixed moderate swells prevail for the remainder of the Atlantic Basin west of 35W. For the forecast W of 55W, the tight pressure gradient between strengthening high pressure in the northwestern Atlantic and troughing extending from the southeastern Bahamas into central Cuba will continue to support widespread fresh E to NE winds and rough seas north of the Greater Antilles through Tue. Elsewhere, a cold front in the central Atlantic will progress southward through Wed, producing fresh to strong winds for areas north of 20N through Thu. South of 20N, moderate to fresh trades will prevail through late this week. 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. $$ Chan