AXNT20 KNHC 211010 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Thu Nov 21 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 0950 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A 1028 mb high pressure center is currently over extreme NE Mexico and is building southward and southeastward across the Gulf of Mexico, behind a cold front this has nearly exited the basin. The pressure gradient between the high and lower pressure along the cold front and across southeast Mexico is supporting fresh to strong northerly winds and very rough seas across most of the Gulf. Offshore of Veracruz, winds are peaking at strong to minimal gale-force, while seas have built to 9-12 ft. Winds offshore of Veracruz will diminish below gale-force in the next few hours as the cold front moves farther into the NW Caribbean and across central Cuba. Basin-wide, winds and seas will gradually subside from west to east late this morning through Fri. Please refer to the High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at websites: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more information. ...MONSOON TROUGH/ITCZ... Most of the monsoon trough remains over the African Continent. An ITCZ stretches westward from just offshore of northern Sierra Leone to 07N34W, then turns northwestward to 11.5N45W. Scattered moderate isolated strong convection is noted from 04N to 11N between the W coast of Africa and 33W. Scattered to locally numerous moderate to strong convection is noted from 06N to 15N between 35W and 43W. The eastern end of the East Pacific monsoon trough is triggering isolated showers and thunderstorms across the Caribbean waters of Panama and Colombia south of 12.5N. ...GULF OF MEXICO... Please read the Special Features section about a Gale Warning near Veracruz. A cold front has nearly cleared the basin overnight, and extends from the Upper Florida Keys across far western Cuba and into the NW Caribbean. Most of the significant convection occurring earlier tonight along and ahead of the front has shifted SE of the basin in recent hours. However, scattered light to moderate convection continues across much of the SW Gulf. North winds behind the front have diminished to moderate to fresh across NW portions to the west of 94W, while fresh to strong NW to N winds prevail over the rest of the Gulf, including the Bay of Campeche. Buoy observations across the basin indicate that seas have subsided to 4-6 ft across NW portions, but are generally 7-10 ft in northerly swell elsewhere across the Gulf, to the south of the northern coastal waters. For the forecast, the cold front sweeping across the basin will shift SE and exit the Gulf and Straits of Florida by sunrise. Minimal NW gale winds offshore Veracruz will also diminish below gale- force by sunrise. Fresh to strong N winds and building seas are expected elsewhere behind the front. High pressure building in the wake of the front will begin to weaken today, with marine conditions gradually improving from W to E through the end of the week. The high pressure will shift to the NE Gulf early Sun when gentle to moderate SE to S winds are expected over the eastern Gulf, and moderate to locally fresh SE to S return flow develops over the western Gulf. ...CARIBBEAN SEA... Convergent southeasterly winds to the south of the cold front over the Yucatan Channel and NW Caribbean are initiating scattered showers and thunderstorms ahead of the front from the Gulf of Honduras to west central Cuba. A modest surface trough is generating patchy showers between Jamaica and Haiti. Fresh NW winds and seas of 4 to 6 ft are present behind the cold front, across the waters of to the Yucatan Peninsula and Channel, and extend to the coastal waters of Belize. Light to gentle winds with 1 to 3 ft seas are noted north of Costa Rica and Panama. Gentle to moderate ENE to SE winds and seas at 3 to 4 ft prevail elsewhere in the Caribbean Sea. For the forecast, the cold front will continue moving southeastward and reach from central Cuba along 80W to the Gulf of Honduras by around sunrise, reach from eastern Cuba to near Cabo Gracias a Dios, Nicaragua by Fri morning, and from the Windward Passage to near the Costa Rica- Panama border Sat morning, where the front should stall and gradually dissipate. Fresh to strong N winds and building seas will follow the front through Sat before winds begin to veer NE to E through Sun and diminish slightly. ...ATLANTIC OCEAN... A cold front curves southwestward from the north-central Atlantic across 31N44W to 26N57W, then continues as a stationary front to 27.5N68W. Patchy showers are found up to 90 nm along either side of this boundary. To the southeast, a surface trough runs northeastward from near the northern Leeward Islands to 27N47W. Scattered showers and isolated thunderstorms are occurring up to 100 nm along either side of this feature. Farther east, convergent southerly winds are producing scattered moderate convection north of 24N between 38W and 42W. Across the Tropical Atlantic, another surface trough is inducing scattered moderate to strong convection from 06N to 15N between 35W and 50W. An upper-level low near 31N21W continues to trigger isolated thunderstorms near the Canary Islands. Refer to the Monsoon Trough/ITCZ section for additional weather in the Atlantic Basin. The northern portion of the cold front moving across the Gulf of Mexico has moved offshore of Florida and the SE U.S. overnight, and extends from 31N77W to central Florida near Ft Pierce. Moderate to fresh SW winds and seas at 4 to 7 ft are evident north of 28N between 68W and the front. Behind the front NW to W winds of 20 to 30 kt are spilling offshore of the SE U.S. coast and north Florida and over the offshore waters, where seas have built to 6-8 ft. Farther east near the cold/stationary front mentioned earlier, moderate SW to W winds and 6 to 11 ft seas in large NW swell dominate north of 26N between 35W and 75W. To the south, a 1016 mb high is centered near 24N69W, and extends an E to W ridge between the surface trough crossing 50W and the Bahamas. Gentle anticyclonic winds with 5 to 7 ft seas in moderate northerly swell prevail over these waters. Gentle to moderate with locally fresh southerly winds and 4 to 6 ft seas prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, the cold front has stalled across the NE offshore zones, along about 26N-27N, and will meander through Fri. The new cold front across the NW zones off of Florida is expected to reach from 31N74W to central Cuba this morning, from 31N68W to eastern Cuba by Fri morning, and from 31N61W to near the Windward Passage on Sat morning. Then, the front will stall in that general vicinity and gradually dissipate through the weekend. Expect fresh to strong winds and building seas on either side of the front N of 26N through Sat. $$ Stripling