000 AXNT20 KNHC 220014 CCA TWDAT Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 0005 UTC Mon Nov 22 2021 Corrected to include latest information on the Cumbre Vieja volcano 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 1800 UTC surface analysis and satellite imagery through 2345 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 Tue. North gale-force winds are expected north of 30N and just west of the front by late 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 axis passes through the coastal plains of Guinea-Bissau near 12N16W and continues southwestward to 09N20W, where latest scatterometer data indicates that it transitions to the ITCZ to 06N30W to 06N38W to 06N45W, and northwest to 10N49W to 11N54W and to the coast of Venezuela at 09N61W. Scattered moderate to isolated strong convection is within 60 nm south of the ITCZ between 30W-34W, and within 60 nm north of the ITCZ between 34W-37W. Scattered moderate convection is within 60 nm north of the ITCZ between 27W-29W. GULF OF MEXICO... High pressure ridging extends from a 1026 mb high that is located over northern Georgia southwestward to over southeastern Louisiana and to near 25N95W. Latest ASCAT data shows generally light to gentle northeast to east winds over the western half of the Gulf, and gentle to moderate northeast to east winds over the eastern half. Seas are in the 2-4 ft range, with the exception of the slightly higher seas of 3-5 ft over the eastern half of the Gulf. For the forecast, the aforementioned high pressure will gradually shift eastward tonight into Mon in response to a large upper-level trough that is over the mid-west section of the United States. This trough will drive a strong cold front over the NW Gulf early on Mon. The cold front will quickly move southeastward and exit the Gulf region by Mon evening. Fresh to strong northerly wind will be expected behind the front, mainly over the eastern and southern Gulf near Veracruz, Mexico late Mon into 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. 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. The GOES-E satellite imagery animation shows a surface disturbance near 70W. This feature has been tracking westward all day. Scattered showers are possible south of 15N between 67W-70W. Latest ASCAT pass over this feature indicates a northeast to southeast wind shift across it, with winds of gentle to moderate speeds. The eastern segment of the E Pacific monsoon trough extends eastward to just inland the coast northwestern Colombia. Scattered showers and isolated thunderstorms are confined to the southwestern Caribbean waters south of about 14N and west of 79W to Central America and over northern Colombia, where the activity is increasing. Isolated showers are possible elsewhere west of 78W. The latest ASCAT data also indicates gentle to moderate trades over just about the entire basin, except south of 15N and east of 80W where stronger trades of fresh speeds are present. Seas are in the range of 2-4 ft, except for slighter higher seas of 3-5 ft from 11N to 15N west of 72W. For the forecast, the gentle to moderate trades will continue across most of the basin through Mon night. A cold front will reach the Yucatan Channel by Mon evening, and extend from eastern Cuba to the Gulf of Honduras by Tue evening. Fresh to locally strong winds and building seas are expected across the western Caribbean, the Windward Passage and Mona Passage likely through Thu as high pressure builds to the north of the area in the wake of the front. ATLANTIC OCEAN...Corrected Please see the Special Features section above for details regarding an upcoming gale event. A shear line extends from near 31N56W to 28N68W and to just east of Stuart, Florida. Recent ASCAT data shows fresh to strong northeast to east winds north of this feature. Seas with these winds are in the 8-10 ft range. Scattered showers are within 120 nm north of the shear line between 71W-74W and between 77W-80W. Gentle to moderate east winds are south of the shear line. Upper-level cyclonic wind flow covers the Atlantic Ocean from 15N northward from 40W eastward. The large upper-level trough that is in this area is sustaining a cold front that extends from 31N32W to 23N35W to 21N46W and to 21N56W. A trough is about 225 nm to 350 nm to the SSE of the cold front. A post-frontal trough is about 150 nm to 270 nm to the northwest and north of the cold front. Broken to overcast multilayer clouds along with isolated showers and thunderstorms are seen from 10N to 15N between 40W and 60W, and north of 20N between Africa and the first surface trough. Similar activity is north of 20N between the cold front and 65W. Seas range from 8-12 ft north of 23N between 30W-40W. Seas range from 3-4 ft from the Cabo Verde Islands northward between Africa and the first surface trough. Seas range from 4-6 ft elsewhere south of 20N and east of 60W. Fresh to strong winds are from 27N northward between 15W and 43W. The wind speeds are moderate or slower elsewhere south of 20N and east of 60W. 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 remain over the northern forecast waters through tonight, before lifting north as warm front ahead of a strong cold front that will move off the northeast Florida coast on Mon. The next cold front will reach from near Bermuda to eastern Cuba late on Tue. Fresh to strong winds and building seas are expected on either side of the front beginning on Tue. Gale force winds are expected north of 30N and just west of the front by late Tue. $$ Aguirre