000 AXNT20 KNHC 162120 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Mar 17 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Caribbean Sea Gale Warning: The pressure gradient from 1025 mb high pressure well north of the area combined with 1008 mb low pressure over northern Colombia will support gale-force winds within 90 nm north-northwest of the Caribbean coast of Colombia late tonight through early Wed. Seas are expected to build 8 to 12 ft, peaking around sunrise Wed. Another round of gale-force winds is forecast for the same area Wed night, with similar conditions possible again Thu night. Fresh to near gale-force winds will persist elsewhere and otherwise in the south-central Caribbean through the upcoming weekend. Gulf of Mexico Gale Warning: A cold front is forecast to enter the northwest Gulf of Mexico on Wed. Minimal gale-force winds will occur across the Veracruz region in the wake of the front by Thu. The gale-force winds will end by Wed night and the cold front will exit the southeast Gulf on Fri. Seas will peak around 8-10 ft in and near the area of gale-force winds late Thu afternoon and early Thu evening before subsiding as the winds diminish. Please read the latest NWS High Seas Forecast from the National Hurricane Center at the website: www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details on both Gale Warnings. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea near 10N15W to 03N24W. The ITCZ continues from 03N24W to 00N39W. Scattered moderate and isolated strong convection is noted from 00N-06N between 20W-29W. Scattered moderate convection is noted from 02N-07N between 07W-13W offshore of Sierra Leone and Liberia. GULF OF MEXICO... See the Special Features section above for more information on the Gale Warning over the southwest Gulf of Mexico. Weak surface ridging prevails across the Gulf of Mexico anchored by 1025 mb high pressure in the Atlantic Ocean west-northwest of Bermuda. Mainly moderate to locally fresh return SE-S flow was noted by earlier scatterometer data. Available surface observations indicate seas of mainly 3-5 ft across the basin, locally to 6 ft in the central Gulf. Some isolated showers and thunderstorms were noted in the northern Gulf in modest and moist southwesterly flow aloft. Fresh to locally strong southerly winds will develop over the western and central Gulf by tonight into Wed ahead of the next cold front forecast to reach the northwest Gulf of Wed. This front will exit the southeast Gulf on Fri. Later in the weekend, fresh to strong winds and building seas are expected in the NE Gulf as a strong high pressure settles over the Carolinas. CARIBBEAN SEA... See the Special Features section above for more information on the Gale Warning over the south-central Caribbean Sea. Otherwise, the pressure gradient due to 1025 mb high pressure well north of the area west-northwest of Bermuda and 1008 mb low pressure over northern Colombia is supporting fresh to strong winds south of Hispaniola, and across the approach and through the Windward Passage. Mainly moderate to fresh trades prevail elsewhere per earlier scatterometer data. Seas of 4-7 ft prevail outside of the south-central Caribbean Sea, except 3-6 ft in the northwest Caribbean. Scattered showers are occurring in the eastern Caribbean Sea near the Leeward Antilles, as well as in the southwest Caribbean and in the northwest Caribbean across Nicaragua and Honduras and adjacent waters. Fresh to strong winds are forecast to persist in the Windward Passage tonight and south of Hispaniola tonight through Thu night. Fresh to strong E-SE winds are expected in the Gulf of Honduras tonight through Wed night. Mainly moderate to fresh trades will dominate the remainder of the basin. A decaying cold front is forecast to enter the far northwest Caribbean Fri night with little fanfare. ATLANTIC OCEAN... An elongated cold front stretches from deep low pressure well north of the area in the east-central Atlantic through 32N42W to 22N55W to 22N69W, with the tail of the front curving and extending northwest as a dissipating stationary front to just northeast of the central Bahamas near 26N76W. A pre-frontal trough is noted within 120-240 nm southeast-south of the front. Scattered showers are noted ahead of both features. Earlier gale- force winds that were occurring north of 28N and west of the cold front to 60W have diminished to fresh to strong, however very large seas in fresh northerly swell continue to propagate through the central Atlantic waters, up to around 25 ft near 31N55W per earlier altimeter data. The outer edge of this large swell is impacting the waters west of 65W where seas of 8-12 ft are found north of the front between 65W-73W, with seas of 4-7 ft elsewhere west of 65W and east of the Bahamas. High pressure of 1025 mb is located west-northwest of Bermuda near 33N70W. Mainly gentle winds are found north of the decaying frontal boundary and west of 65W, except moderate to locally fresh within about 120 nm north-northeast of the boundary. Meanwhile a tight pressure gradient is noted offshore of the Carolinas with 1017 mb low pressure noted near Cape Lookout, North Carolina. This low is along a stationary front which reaches southwest-west across Georgia and an area of fresh to strong winds is north of 30N between 75W-80W. The weakening frontal boundary will continue to wash out west of 65W tonight into early Wed. The large and long period northerly swell behind the front, and associated with the deep low pressure system well north of the area, will reach the Atlantic passages east of La Mona passage by early Wed morning. The next cold front is expected to push off the Florida coast on Thu night. Fresh to strong southerly winds are expected ahead of this front through Fri. By the weekend, strong winds and building seas are expected to impact the coast of Florida as a strong high pressure settles over the Carolinas. $$ Lewitsky