000 AXNT20 KNHC 300438 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Thu Dec 30 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 cold front reaching from the eastern Azores to the central Atlantic near 20N47W will stall and dissipate west of 35W through early Thu morning. A second, reinforcing cold front moving across the north central Atlantic will move across the waters north of 25N and east of 50W through Thu night, accompanied by winds to minimal gale force near 31N39W Thu afternoon. Very rough seas to 18 ft will also accompany the front in NW swell, with swell to 8 ft reaching as far south as 22N east of 55W through Thu night. Winds will diminish through Fri as the front stalls along 27N. Seas to 12 ft will linger through Fri north of 22N between 35W and 55W. ...Caribbean Gale Warning... High pressure centered northeast of the Bahamas will build through Fri, supporting fresh to strong trade winds across the central Caribbean Sea through Sun, with winds pulsing to minimal gale force off Colombia Thu night, with seas to 14 ft. Gale force winds are expected to pulse once again on Fri night. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more information. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic from the coast of Sierra-Leone near 08N13W to 07N16W. The ITCZ continues from 07N16W to 03N30W to 01N47W near the coast of NE Brazil. Scattered moderate convection is noted from 01N to 05N along the length of the ITCZ. ...GULF OF MEXICO... The gradient between high pressure in the western Atlantic and lower pressure over eastern Mexico is supporting moderate to locally fresh SE to S winds across the majority of the Gulf. Seas are predominately 5 to 7 ft across the basin, with the exception of 2-4 ft seas in the SE Gulf. For the forecast, the surface high pressure centered NE of the central Bahamas will remain nearly stationary through Sun and support moderate to locally fresh return flow across the central and western basin, increasing to fresh to strong Fri night as the pressure gradient increases ahead of a strong cold front forecast to come off the coast of Texas Sat evening. Strong to near gale force northerly winds will follow this front, with gale conditions affecting the NW and SW basin on Sun/Mon. The front is forecast to move east of the gulf Mon morning. Winds and seas associated with the front will gradually subside through Mon night. ...CARIBBEAN SEA... Please see the Special Features section for details about the gale warning in effect for the Caribbean. A 1022 mb high pressure centered north of the area is supporting fresh to strong trade winds with seas of 5 to 8 ft across the central Caribbean. Fresh NE to E winds are noted across the eastern part of the basin, including the Anegada passage where a shear line is analyzed. Seas in this area range from 4 to 6 ft. Elsewhere, moderate E to SE winds and 3 to 5 ft seas are observed. Water vapor satellite imagery reveals a very dry airmass stretching across the basin, thus, no significant shower or thunderstorm activity is evident at this time. For the forecast, the high pressure centered NE of the central Bahamas will remain nearly-stationary through Sun, supporting moderate to fresh trade winds across the Caribbean, except for locally strong winds in the Gulf of Honduras, central Caribbean and portions of the SW basin. Gale force winds are expected off Colombia Thu night and Fri night. ...ATLANTIC OCEAN... Please see the Special Features section for details about the gale warning in effect for the Atlantic. A 1022 mb high pressure located northeast of the central Bahamas near 26N67W dominates the weather over the western Atlantic. This is generating mostly light to gentle anticyclonic flow and 3 to 5 ft seas west of 65W. Moderate SW winds are observed off the northeast Florida coast in a recent scatterometer pass, along with moderate E winds south of 22N. Farther east, a surface trough is analyzed from 31N43W to 28N46W along with a cold front that extends from 31N26W to 20N47W in the central and eastern Atlantic. A scatterometer pass this evening reveals strong winds within 140 nm of either side of the trough axis. Satellite derived winds also observe fresh westerly winds behind the cold front with strong SW winds extending 300 nm ahead of the front north of 24N. Scattered moderate convection is observed within 300 nm east of the front north of 24N. Significant wave heights of 12-14 ft area noted from 26N to 31N between 30W and 50W with 8 ft seas extending as far south as 17N in the central Atlantic. The subtropical ridge extends from high pressure over the Iberian Peninsula to 28N20W. Gentle to moderate NE winds and 5 to 7 ft seas are observed south of the ridge. For the forecast west of 65W, the high pressure centered NE of the central Bahamas will remain nearly-stationary through early Sun. The high pressure will weaken and move east Sun ahead of a strong cold front moving off the northeast Florida coast late Sun night. Strong to near gale force winds and building seas associated with the front will affect the offshore waters N of 26N Sun and Mon. $$ Nepaul