000 AXNT20 KNHC 190507 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Fri Nov 19 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 0455 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A cold front extends from SE Louisiana to Tamaulipas, Mexico. Gale-force NW-N winds are forecast to develop offshore of Veracruz this afternoon as strong high pressure strengthens behind the front. Peak seas of around 12 ft are expected with the gale-force winds. Winds in the region are forecast to diminish to below gale-force late tonight as the high pressure shifts eastward allowing the pressure gradient to slacken. The cold front will reach the SE Gulf this weekend, becoming stationary from near Naples, Florida to the Bay of Campeche. 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. It reaches the Atlantic through the coast of Guinea- Bissau near 12N16W and extends to 08N17W. The ITCZ then continues from 08N17W to 05N25W to 07N36W. A surface trough is just west of the ITCZ along a position from near 09N39W to 03N44W. The ITCZ resumes near 06N45W to 04N51W. Scattered moderate to isolated strong convection is found from 03N to 16N and E of 46W. GULF OF MEXICO... Please see the Special Features section above for details on a Gale Warning that is in effect for waters near Veracruz, Mexico. A cold front continues to move across the NW Gulf of Mexico, extending from SE Louisiana to Tamaulipas. Scattered moderate convection is noted in the W Gulf, mainly from 22N to 27N and W of 95W. Recent scatterometer satellite data and surface observations show strong to near-gale force NE winds behind the frontal boundary. The strongest winds are occurring within 100 nm of the Texas and SW Louisiana coasts. Seas of 6-9 ft are also found in the described area, with the highest seas occurring off Tampico. Plenty of tropical moisture ahead of the front and divergence aloft result in a large area of cloudiness and widespread shallow showers affecting most of the Gulf, especially E of 90W. Satellite-derived wind data depict fresh to strong NE winds N of 21N and the cold front and W of 87W. Moderate or weaker winds prevail elsewhere. Seas of 3-6 ft are found in the SE Gulf and Bay of Campeche, while seas of 1-3 ft are prevalent in the NE Gulf. For the forecast, the aforementioned front will continue to move across the northern and western Gulf through Fri, then stall from near Naples, Florida, to the Bay of Campeche this weekend, before dissipating. Strong winds, with frequent gusts to gale force, and rough seas follow the front. Winds are expected to reach gale force off Veracruz, Mexico on Fri. Looking ahead, another cold front will move into the northwest Gulf early Mon, and move south of the basin Tue. High pressure will build over the northern Gulf in the wake of the front. CARIBBEAN SEA... The favorable upper level dynamics that led to multiple days of unsettled weather in the NW Caribbean Sea have shifted northward, allowing for a much drier weather pattern to return to the region. A surface trough extends from the SE Gulf to Guatemala and divergence aloft is enhancing the development of convection in the area, with a couple of showers spilling over into the Caribbean waters off NE Yucatan. A few showers are also present in the SW Caribbean, mainly within 100 nm of the coast of Nicaragua. The rest of the basin enjoys fairly tranquil weather conditions. A recent scatterometer satellite pass show fresh to locally strong trades in the central and NE Caribbean Sea, with the strongest winds occurring offshore NW Colombia. Strong trades are also noted within 100 nm to the south of Hispaniola. Moderate or weaker trades prevail elsewhere. Seas of 4-7 ft are found in the SW, central and E Caribbean, while 2-4 ft are prevalent in the rest of the basin. For the forecast, fresh to locally strong 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 will further diminish early next week, ahead of a stronger cold front moving through the Gulf of Mexico Mon. The stronger front will reach the Yucatan Channel by late Mon night and extend from eastern Cuba to the Gulf of Honduras by late Tue. ATLANTIC OCEAN... A large area of showers and isolated thunderstorms affects the western tropical Atlantic, mainly N of 24N and W of 74W. This is associated with a surface trough that extends from 24N to 30N along 80W and divergence aloft thanks to the upper level trough that covers most of the eastern United States. A recent scatterometer satellite pass show fresh to locally strong cyclonic winds across the NW Bahamas and off SE Florida, likely associated with the storms in the area. Farther east, a cold front enters the basin near 31N42W and quickly transitions into a shear line near 30N44W that stretches southwestward to near the central Bahamas. Isolated showers are noted near the shear line. Satellite-derived wind data indicate that fresh to strong NE-E winds are found behind the shear line. Fresh NE-E winds are noted between the shear line the islands of the NE Caribbean Sea. Seas of 6-10 ft are found W of the shear line, with peak seas higher than 8 ft occurring N of 25N and between 44W and 57W. A weak surface trough is located 300 nm E of the Leeward Islands along 57W and a few showers are observed east of the trough axis. Farther east, a weakening surface trough extends from 26N34W to 23N33W to 16N42W and the trough is devoid of any significant convection. The rest of the basin enjoys fairly tranquil weather conditions, with moderate or weaker winds and seas of 3-6 ft. 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 from 22N65W into the central Bahamas. Fresh to strong NE to E winds and rough seas are evident a couple of hundred miles to the north of this line. The shear line will dissipate through tonight in advance of a cold front that will move off the NE Florida coast Fri. The front will stall along roughly 28N this weekend, before lifting north ahead of a strong cold front that will move off the northeast Florida coast Mon. The second front will reach from Bermuda to eastern Cuba by late Tue. $$ DELGADO