000 AXNT20 KNHC 161745 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Mar 16 2023 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 1750 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning and Significant Swell Event: A cold front extends from 31N53W to Punta Rucia, Dominican Republic to the NW Caribbean where it starts to dissipate. A small area of gale force northerly winds prevails behind the front in the region from 22N to 24N between 62W and 64W. The front will continue to move SE and reach from 20N55W through the northern Leeward Islands by Fri morning. Strong to gale-force NW winds will shift eastward immediately behind the front and through the SE waters through tonight. Large N swell accompany this front, with seas of 12 ft or greater spreading southward to 22N and E of 69W by this evening. Currently, peak seas of 13-16 ft are N of 26N between 55W and 70W. Seas behind the front are not expected to subside below 12 ft until Sun as the front moves E of 35W. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and Offshore Waters Forecast at https://www.nhc.noaa.gov/marine/offshores.php for more details on these events. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Africa near 06N10W then continues SW to near 03N17W. The ITCZ extends from 03N18W to 00N27W to 01S34W. Scattered moderate convection is noted from 07S to 04N between 26W and 50W. ...GULF OF MEXICO... High pressure across the eastern U.S is building across the Gulf, behind a weakening cold front that currently extends across the NW Caribbean. In the far western Gulf, lower pressures are developing ahead of the next cold front. The pressure gradient between the ridge and lower pressure along Mexico and coastal waters is producing fresh to locally strong return flow W of 92W. The strongest winds within this region are N of Tampico and W of 94W where seas are in the 7 to 9 ft range. Moderate SE winds dominate the remainder basin along with seas of 4 to 6 ft, except for fresh E winds in the Straits of Florida. For the forecast, fresh to strong return flow will spread to the entire Gulf tonight, ahead of the next cold front. This front will move into the NW Gulf Fri morning, reaching from Apalachee Bay, Florida to the central Bay of Campeche Sat morning. Brief gale- force N winds are expected behind the front offshore of the upper Mexican waters Fri afternoon, shifting to offshore Veracruz Fri night. The front will then stall and weaken across the SE Gulf, and sink slowly SE across the Yucatan Channel Mon night. ...CARIBBEAN SEA... High pressure of 1025 mb located over South Carolina extends a ridge axis southward into the NW Caribbean just to the N of a dissipating cold front that extends across the Windward Passage to 19N85W. The pressure gradient between these two features is supporting fresh to strong NE to E winds in the Windward Passage and offshore waters of the NW Caribbean N of 18N where seas are in the 5 to 8 ft range. Another surface ridge extends from the E central Atlantic to the Lesser Antilles offshore waters, which is supporting a weak pressure gradient ahead of the front as well as resulting in gentle to moderate trade winds and seas to 6 ft across the remainder Caribbean. For the forecast, surface ridging extending near the Lesser Antilles will shift NE through the weekend, as a cold front sinks S-SE across the northern basin. The front will reach from the northern Leeward Islands to the central Caribbean along 17N Fri morning, then become aligned E to W along 15N Sat before gradually dissipating by Sun. Strong winds will follow the front, locally higher in Atlantic passages, with large N swell spreading through Atlantic passages early Fri through Sat. Another front is expected to move slowly SE through the SE Gulf Sun and stall across the Yucatan Channel Mon night. ...ATLANTIC OCEAN... A cold front extends from 31N53W to the Turks and Caicos Islands to far eastern Cuba. Gale force winds are already occurring in a narrow band just behind the front over the SE Bahamas and likely extends eastward behind to front to near 69W. New large N swell is following this system. Please, see the Special Features section for more information. Seas of 8 to 11 ft are found behind the front and E of 76W, and 12 ft and greater to the N of 27N. A wide band of multi-layer clouds with embedded showers and isolated thunderstorms is associated with the front, and it is affecting most of the SE Bahamas and the Turks and Caicos Islands, including also the Old Bahama Channel. A second cold front stretches from 31N21W to 24N40W. A narrow band of mainly low clouds with possible showers is related to the front. Gentle to moderate NW winds and seas of 9 to 13 ft in NW swell are behind the front. A 1021 mb high pressure is located between the fronts near 29N39W. This feature dominates most of the east and central Atlantic. Mainly moderate NE to E trades are blowing across the tropical Atlantic, with seas of 7 to 9 ft in NW to N swell prevailing E of the Lesser Antilles. For the forecast W of 55W, the cold front will continue moving SE and reach from 20N55W through the northern Leeward Islands by Fri morning. Strong to gale-force NW winds immediately behind the front will exit the SE Bahamas this morning, and shift across the SE waters through tonight. Large N swell will accompany this front, with seas of 12 ft or greater will spreading to 22N and E of 73W. Another cold front is expected to move off NE Florida late Sat, with fresh to strong southerly winds ahead of it Fri evening through Sat. The new front is expected to reach from 31N72W to S Florida late Sun before stalling. $$ Ramos