000 AXNT20 KNHC 220518 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Nov 22 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 0430 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A strong cold front is forecast to reach from near Bermuda to eastern Cuba by late Tue. Fresh to strong winds and building seas are expected on either side of the front beginning on Mon night. North gale-force winds are expected north of 30N and just west of the front by Tue. Seas are forecast to build to 10-15 ft with these winds. Please refer to the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Guinea-Bissau near 11N16W to 08N21W. The ITCZ continues from 08N21W to 04N37W to the coast of Brazil near 01N50W. Scattered moderate to strong convection is along the ITCZ from 01N to 09N between 24W and 40W. GULF OF MEXICO... High pressure ridging extends across most of the Gulf from a 1021 mb high over South Carolina. At 0300 UTC, a trough was analyzed in the NW Gulf from 29N94W to 23N90W. Isolated showers are noted near this feature. The latest ASCAT data shows mostly light to gentle winds across the western Gulf with gentle to moderate NE winds in the eastern Gulf. Seas are 2-4 ft across the basin. For the forecast, a cold front will enter the basin by early Mon and move quickly SE, exiting the Gulf region by Mon evening. Fresh to strong northerly winds are expected behind the front, mainly offshore Tampico, Mexico late Mon, and over the northeast Gulf Mon night into early Tue. High pressure is forecast to build in behind the front. Fresh southerly return flow will set up across the NW Gulf by the middle of the week ahead of the next cold front forecast to reach the Gulf waters by Thu night. Strong to near gale force winds are likely behind the front over the far western Gulf Thu night and Fri, with small pockets of gale force winds possible off the coast of Mexico. CARIBBEAN SEA... Broad-upper level anticyclonic wind flow covers the entire Caribbean Sea per upper-level wind data. Water vapor imagery depicts subsidence and resultant in rather stable atmospheric conditions over the central and eastern Caribbean, with only shallow moisture evident there. GOES-R satellite imagery indicated a trough in the east-central Gulf south of the Mona Passage from 17N68W to 09N69W. Isolated thunderstorms are noted within 90 nm of the trough. Scattered moderate convection is also noted in the SW Caribbean, S of 16N and W of 76W with the influence of the monsoon trough. Moderate to fresh winds are noted near the Colombia coast with light to gentle trades elsewhere. Seas in the western Caribbean are 1-3 ft with 3-5 ft in the central and eastern basin. For the forecast, mainly gentle to moderate trades will prevail across much of the Caribbean Sea through Mon. A cold front will reach the Yucatan Channel by Mon evening, and extend from eastern Cuba to eastern Honduras by late Tue. Fresh to locally strong N to NE winds and building seas are expected across the western Caribbean, the Windward Passage and Mona Passage likely through Thu as high pressure builds N of the area in the wake of the front. ATLANTIC OCEAN... Please see the Special Features section above for details regarding an upcoming gale event. A trough extends off the Florida coast from 31N80W to 25N80W. A shearline stretches across the central and western Atlantic from 31N53W to 28N66W to 27N79W. The combination of the shearline, trough and abundant moisture is leading to scattered moderate convection near the Florida coast and the northern Bahamas from 26N to 30N and W of 70W. Isolated thunderstorms are also noted across the Straits of Florida and southern Bahamas. Moderate to fresh easterly winds are noted north of the shearline near the Florida coast with light to gentle easterly winds elsewhere in the western Atlantic with seas 4-7 ft. In the central Atlantic, two troughs are noted from 27N54W to 21N54W and from 27N63W to 21N62W. Scattered showers are near these features. Moderate winds are along these two troughs, with gentle to moderate winds prevailing across the central Atlantic. Seas range 5-8 ft. A cold front extends across the eastern and central Atlantic from 31N19W to 22N30W to 20N47W. Scattered moderate convection is east of the front moving into western Africa, N of 14N and E of 21W. Moderate westerly winds are behind the front. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Medium ash concentration is in the vicinity of the volcano, while lower concentration is elsewhere. 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, the shear line will weaken as it lifts northward tonight. A strong cold front will move off the coast of northeast Florida by midday Mon. The cold front will reach from near Bermuda to eastern Cuba late on Tue. Fresh to near gale force winds and building seas are forecast on either side of the front beginning early Tue. Gale force N winds are expected just behind the front N of 30N and E of 75W Tue afternoon. The front will be accompanied by scattered showers and thunderstorms. In the wake of the front, high pressure will build near the Carolina coast Wed night through Thu night. $$ AReinhart