000 AXNT20 KNHC 180455 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Thu Nov 18 2021 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 0444 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: Gale-force NW-N winds will develop offshore of Veracruz Fri afternoon behind a cold front that will move through the basin. Seas will build to around 15 ft with the gale-force winds. Conditions should diminish below gale-force by Fri evening. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more information. ...MONSOON TROUGH/ITCZ... The monsoon trough remains mostly confined to the African continent, reaching the Atlantic through the coast of Sierra Leone near 08N13W and extending to 06N15W. The ITCZ extends from 06N15W to 02N24W to 04N34W, then resumes west of a surface trough from 04N42W to 02N49W. The surface trough extends from 09N35W to 01N41W. Scattered moderate to isolated strong convection is noted from the equator to 11N and between 22W to 41W. GULF OF MEXICO... Please see the Special Features section above for details on a Gale Warning in effect near Veracruz, Mexico. The Gulf of Mexico is in the southwestern periphery of a 1029 mb high pressure system located near Bermuda. A prominent cold front sliding SE over the central United States is transporting tropical moisture northward into the basin, combined with divergence aloft results in scattered showers over most of the eastern half of the Gulf, mainly E of 91W and N of 24N. A recent scatterometer satellite pass show fresh to locally strong E winds over SE Gulf waters, including the Florida Straits. The rest of the Gulf enjoys fairly tranquil weather conditions and moderate or weaker winds. Seas of 4-6 ft are present in the NW and SE Gulf waters, while 1-3 ft seas prevail elsewhere. For the forecast, a cold front moving into coastal Texas will enter the northwest Gulf early Thu. Strong winds and rough seas will follow the front over the western Gulf, reaching gale force off Veracruz Fri. The front will stall from near Tampa Bay, Florida to 24N95W to Veracruz by Sat, then start to dissipate. Looking ahead, another front will move into the northwest Gulf early Mon, and reach from southwest Florida to the southwest Gulf by late Mon night. CARIBBEAN SEA... A surface trough extends from the Yucatan peninsula to N Honduras, across the Gulf of Honduras. Plenty of tropical moisture in the NW Caribbean and divergence aloft allows for scattered showers and isolated thunderstorms to affect the waters W of 84W. The rest of the basin enjoys fairly tranquil weather conditions. The modest pressure gradient between the strong subtropical ridge near Bermuda and lower pressures across N South America result in fresh to strong trades across the central Caribbean, including the Windward and Mona Passages, and the NW Caribbean N of 20N. A recent scatterometer satellite pass depict a small area of near- gale force winds within 100 nm of the Barahona peninsula in southern Hispaniola. Moderate to locally fresh trades are prevalent elsewhere. Seas of 6-9 ft are found in the central, SW and NE Caribbean Sea, with the highest seas occurring offshore southern Hispaniola. Seas of 2-5 ft prevail elsewhere. For the forecast, fresh NE winds persist in a broad swath from the northeast Caribbean into the southwest Caribbean. Winds and seas will diminish through Fri as high pressure north of the area shifts east, ahead of a cold front moving into the Gulf of Mexico and western Atlantic. Winds and seas further diminish early next week, ahead of a second cold front moving through the Gulf late Mon and Mon night. ATLANTIC OCEAN... A cold front enters the tropical Atlantic near 31N49W and extends to 24N67W, where it transitions to a shear line that continues across the central Bahamas. A few shallow showers are noted near the frontal boundary. Fresh to locally strong winds are occurring north of the cold front and shear line, extending to 30N. Fresh to locally strong trades are also present S of 22 and W 55W, with the strongest winds occurring between Haiti and Great Inagua in the SE Bahamas, at the entrance of the Windward Passage. Seas of 6-10 ft are present to the W of the cold front and shear line, with the highest seas occurring N of 29N and between 50W and 58W. Farther east, a 1012 mb low pressure is near 24N33W. A weakening surface trough associated with the low pressure extends from the low to 22N40W. No deep convection is seen in association with the low pressure or associated trough. Fresh to locally strong mainly easterly winds are observed N of 28N and between 22W and 29W. Seas are 5-8 ft prevail in the central and E tropical Atlantic. Moderate or weaker winds and fairly tranquil weather conditions are present elsewhere. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Marine and aviation interests should monitor this ongoing situation by reading the Volcanic Ash Advisory issued by Meteo-France, at http://vaac.meteo.fr/volcanoes/la-palma/. For the forecast, a shear line extends along 25N into the central Bahamas. Fresh to strong NE to E winds are evident a couple of hundred miles to the north of this line. The shear line will dissipate Thu in advance of a cold front that will move off the NE Florida coast. The front will stall from Bermuda to central Florida Sat, then lift north again Sun ahead of a stronger front moving off the northeast Florida coast late Mon. The second front will reach from Bermuda to eastern Cuba by Tue night. $$ DELGADO