000 AXNT20 KNHC 202320 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Dec 20 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A 1012 mb extratropical low in the central Gulf of Mexico is producing northerly gale force winds. The low should deepen and steadily move northeastward and reach the Florida peninsula on Tue. Gale force N winds and seas of 10 to 13 ft are anticipated to continue in the W semicircle of the low, but are likely to only cover a limited region. As the low crosses Florida, it will drag a cold front across the SE Gulf by Tue night. Strong to near gale NW winds behind the front will quickly diminish on Wed. Please refer to the latest High Seas Forecast issued by the National Hurricane Center, at the following website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. Atlantic Gale Warning: The low pressure over the central Gulf of Mexico will move northeastward to offshore NE Florida and Georgia by late Tue. Strong southerly winds are expected ahead of the low and E of Florida by early Tue afternoon. Near the low, strong to gale force SW to W winds are expected mainly over waters N of 27N W of 70W Tue through Wed. Marine conditions will gradually improve from W to E across the waters N of 27N W of 65W on Thu. Please refer to the latest High Seas Forecast issued by the National Hurricane Center, at the following website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. Eastern Atlantic Gale Warning E of 35W: Gale-force winds are forecast by Meteo France in the zone named IRVING, located W of the Madeira Islands. These winds are associated with a low pressure system spinning between the Madeira and the Azores Islands. The forecast indicates westerly force 8 (Beaufort wind scale) in northern Irving with severe gusts. For more details, refer to the Meteo-France High Seas Forecast listed on their website: www.meteofrance.com/previsions-meteo-marine/bulletin/ grandlarge/metarea2 ...MONSOON TROUGH/ITCZ... The ITCZ extends from the coast of Sierra Leone near 08N13W to 05N30W to the coast of Brazil near 02N51W. Scattered moderate convection is noted from 04N-07N between 16W-23W. Similar convection is also seen from 02N-04N between 30W-33W. ...GULF OF MEXICO... A Gale Warning is in effect for the Gulf of Mexico. Please, see the Special Features section for details. Hazardous marine conditions are associated with a deepening low pressure system located over the central Gulf of Mexico near 25N91W. A cold front stretches from the low center across the eastern Bay of Campeche into SE Mexico. Gale force N winds are on the W semicircle of the low while fresh to strong winds follow the front. An area of showers and thunderstorms is within about 240 nm NE quadrant of low center affecting the waters from 24N to 26N between 86W and 91W. Strong storms are possible within this area. Elsewhere, abundant cloudiness dominates most of the Gulf waters with low clouds baking up against the Sierra Madre Mountains. For the forecast in the Gulf region, please refer to the Special Features section for more information. ...CARIBBEAN SEA... The E Pacific monsoon trough is triggering scattered showers and isolated thunderstorms over Panama and regional waters. Elsewhwere, patches of low level moisture, embedded in the trade wind flow, are observed producing isolated to scattered passing showers. One of this patch of moisture is approaching the Leeward Islands and is expected to move across the islands tonight increasing the likelihood of showers. As high pressure moves eastward N of area, the trade winds have diminished. Gentle to moderate winds dominate most of the basin with mainly light winds in the lee of Cuba. For the forecast, as high pressure remains weak and centered well northeast of the Caribbean, the tradewinds will only reach moderate to fresh over the S central Caribbean and tropical N Atlantic with gentle to moderate winds elsewhere for the next several days. A cold front will move through the Yucatan Channel Tue, then reach from E Cuba to Nicaragua by Thu morning, before stalling. Fresh N winds can be expected behind this front. Large N to NE swell will continue in the tropical N Atlantic into Tue. ...ATLANTIC OCEAN... A Gale Warning is in effect for the SW N Atlantic, N of 27N and E of Florida. Please, see the Special Features section for details. A cold front extends from near Bermuda to the NW Bahamas, then continues as a stationary front across the Straits of Florida. Some shower activity is along the frontal boundary. The most recent satellite derived wind data indicate fresh NE winds N of 27N and W of the front. Fresh SW winds are also noted N of 30N and SE of the front between 55W and 70W. E of the front, high pressure of 1020 mb centered near 26N46W dominates the remainder of the Atlantic forecast area. A surface trough is analyzed from 31N20W to 25N31W. For the forecast W of 65W, the above mentioned frontal boundary will begin to retreat northward by early Tue as a warm front. Low pressure over the central Gulf of Mexico will move northeastward to offshore NE Florida and Georgia by late Tue. High pressure will follow the low center with improving marine conditions. $$ GR