000 AXNT20 KNHC 281714 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Tue Dec 28 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... ...Atlantic Gale Warning... A large area of low pressure dominates most of the Atlantic Ocean N of 31N and E of 60W. The associated cold front enters the forecast waters near 31N38W and continues SW to near 24N50W, then westward to 23N60W to 25N71W. The latter part of the front is dissipating, and it is expected to transition to a shearline late today. A recent scatterometer pass provides observations of gale force winds ahead of the front near 31N35W while an altimeter pass indicates sea heights of 20-22 ft behind the front near 31N44W. Fresh to strong winds are noted per satellite derived winds data on either side of the front mainly N of 27N. The front will move southwest through Wed, with gale force winds lifting NE of the area early this afternoon when the gale warning is forecast to expire. Seas will gradually subside accordingly, although 8 to 14 ft seas will persist north of 20N and east of 60W through tonight. 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 extends from the coast of Liberia near 06N10W to 05N20W. The ITCZ continues from 05N20W to 04N30W to 02N40W to the coast of NE Brazil near 02N51W. No significant convection is evident at this time. ...GULF OF MEXICO... High pressure of 1021 mb located E of Florida extends a ridge across Florida into the Gulf waters. The pressure gradient between this system and lower pressures over Texas supports moderate to locally fresh SE to S winds and seas of 2-4 ft over the eastern half of the Gulf, and fresh to locally strong S winds with seas of 4-6 ft over the western half of the Gulf. Patches of low level moisture are moving N across parts of Gulf under a southerly wind flow. Visible satellite imagery shows a well defined swirl of low clouds over the SE Gulf. For the forecast, the ridge extending from the western Atlantic into the Gulf will support moderate to fresh winds across the central and western Gulf through Wed. The ridge will shift eastward, allowing gentle to moderate winds and slight to moderate seas across the entire basin Thu as a weak frontal boundary stalls and dissipates along the Texas coast. Looking ahead, southeast to south winds are expected to increase over the western Gulf by late Fri as low pressure moves into the Central Plains. A strong cold front associated with this low pressure may reach the Texas coast late Sat night. ...CARIBBEAN SEA... High pressure of 1021 mb situated E of Florida dominates the pattern across the Caribbean Sea. The most recent scatterometer passes indicate the presence of fresh to strong northeast winds with seas of 7 to 9 ft off the coast of Colombia, with moderate to locally fresh trades and seas of 5-7 ft across the remainder of the south-central Caribbean. Elsewhere, mainly moderate trades prevail with seas of 3-5 ft. A surface trough is analyzed over the Leeward Islands. Patches of low level clouds with possible showers are near the trough axis affecting the NE Caribbean. This area of moisture will move westward over the eastern Caribbean through Wed. Elsewhere, low- topped trade wind showers are noted. For the forecast, high pressure located N of the Caribbean Sea near the NW Bahamas will strengthen through Thu, supporting fresh to strong trade winds across mainly the central Caribbean through Sat. ...ATLANTIC OCEAN... Please see the Special Features section above for details about the Gale Warning in the Atlantic, forecast to expire at 18Z. High pressure is building over the waters west of 65W in the wake of the above mentioned cold front moving over the central Atlantic. This is supporting mainly light to gentle winds, with the exception of gentle to moderate winds S of 22N. Similar wind speeds are also noted per scatterometer data N of 30N between 70W-77W due to the presence of a low pressure moving eastward N of the area. Farther east, the Atlantic ridge extends from 1026 mb high pressure near Morocco, southeastward to 20N40W, supporting light to gentle winds along the ridge axis. Moderate to fresh trade winds and seas of 4 to 7 ft prevail across the tropical Atlantic south of the ridge axis. For the forecast west of 65W, high pressure currently located E of Florida will shift eastward and strengthen northeast of the Bahamas through Sat. This will support fresh to locally strong NE-E winds across the Atlantic S of 22N W of 70W including Approaches to the Windward Passage. $$ GR