000 AXNT20 KNHC 191021 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A cold front extends from the Florida Panhandle to near Tampico, Mexico. The front will continue to move across the Gulf waters today, then stall from near Naples, Florida, to the Bay of Campeche this weekend, before dissipating. Strong northerly winds and rough seas follow the front. Winds are expected to reach minimal gale force off Veracruz, Mexico early this afternoon, with seas building to around 12 ft. Winds in the region are forecast to diminish to below gale-force tonight. 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 reaches the Atlantic through the coast of Sierra Leone and extends to 05N13W. The ITCZ continues from 05N13W to 03N20W to 06N33W, then resumes W of a surface trough near 07N45W to the coast of French Guiana near 05N53W. Scattered moderate to isolated strong convection can be found from 03N to 10N between 25W and 40W, and from 10N to 16N between 25W and 30W. 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 Gulf region and extends from the Florida Panhandle to near Tampico, Mexico. Recent scatterometer data show fresh to strong northerly winds behind the front. The strongest winds are occurring within 100 nm of the Texas and SW Louisiana coasts. Seas of 6-9 ft are found in the wake of the front, with the highest seas occurring off Tampico, Mexico. Fresh to locally strong NE winds are also noted ahead of the front, particularly N of 22N W of 90W. Moderate or weaker winds prevail elsewhere. Seas of 3-5 ft are noted in the SE Gulf and Bay of Campeche, while seas of 1-3 ft are prevalent in the NE Gulf. Scattered showers with embedded thunderstorms are seen ahead of the front, mainly in the W Gulf. Plenty of tropical moisture ahead of the front and a diffluent pattern aloft result in a large area of cloudiness over the eastern Gulf and the State of Florida. A band of showers and thunderstorms is over the SE Gulf, including the Yucatan Channel. Similar convective activity is also seen over the Straits of Florida. For the forecast, another cold front will enter the northwest Gulf early Mon, and move south of the basin Tue. Fresh to strong winds are expected behind the front. High pressure will build across the Gulf region in the wake of the front. CARIBBEAN SEA... Recent satellite-derived wind data show fresh to locally strong trades in the E and central Caribbean, 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 5-7 ft prevail in the south- central Caribbean, with 3-5 ft elsewhere, except in the lee of Cuba where seas of 1-3 ft are found. Scattered showers are thunderstorms are affecting the Caribbean plains of Nicaragua. A diffluent pattern aloft is helping to sustain this convective activity. Patches of low level moisture with embedded showers are observed elsewhere. For the forecast, the fresh to locally strong winds across the basin are forecast to diminish beginning today as high pressure north of the area shifts east, ahead of a cold front moving off NE Florida today. Winds and seas will further diminish early next week, ahead of a stronger cold front moving through the Gulf of Mexico Mon. The front will reach the Yucatan Channel by late Mon night and extend from eastern Cuba to the Gulf of Honduras by late Tue. Fresh to locally strong winds and building seas are expected in the behind the front. ATLANTIC OCEAN... Abundant cloudiness, with some shower and thunderstorm activity, affects the waters E of Florida to near 70W, including parts of the Bahamas. This is associated with a surface trough that extends E of Florida along 79W/80W and a diffluent pattern aloft. A recent scatterometer satellite pass shows the wind shift associated with the trough axis. A shear-line is analyzed from 31N39W to 27N50W to 22N68W. A few showers are along this feature. Satellite-derived wind data indicate that fresh to strong NE-E winds are found behind the shear line, with seas of 8-12 ft in NE swell based on altimeter data and buoys observations. A weak surface trough is located about 300 nm E of the Leeward Islands along 57W/58W. Shallow moisture with possible showers is associated with this trough. This could reach the Leeward Islands by tonight. Farther east, a surface trough extends from 31N35W to 19N40W. Scattered showers are near the northern end of the trough that is a reflection of an upper-level trough. A 1012 mb low pressure located E of the Madeira Islands near 33N12W is producing some shower activity. Northerly swell, generated by a low pressure system located N of area, will reach the forecast waters late on Sat, building seas to 10-14 ft roughly N of 29N between 25W and 40W by Sun morning. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been active for two months(since 19 September 2021). Medium ash concentration is noted in the vicinity of the volcano, low 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 W of 65W, a cold front will move off the NE Florida coast today, then remain across the northern forecast waters this weekend, before lifting north ahead of a stronger cold front that will move off the northeast Florida coast on Mon. The second front will reach from Bermuda to eastern Cuba by late Tue. Fresh to strong northerly winds and building seas are expected behind the fronts. $$ GR