Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed Jan 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 32N. 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... Caribbean Gale Warning: High pressure north of the area will continue to support strong to near gale force winds over the south-central Caribbean through the latter part of the week. Nocturnal pressure fluctuations will cause these winds to pulse to gale force within 90 nm off the coast of Colombia this morning, and again, this evening. 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 details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Sierra Leone near 07N12W to 02N20W. The ITCZ continues from 02N20W to 01N49W. Scattered showers are noted from 01N to 06N between 16W and 28W. GULF OF MEXICO... A surface ridge extends 1031 mb high pressure over Arkansas across the Gulf of Mexico. This is supporting moderate to locally fresh E winds south of 25N, with 4 to 6 ft seas, and gentle to moderate E to SE winds north of 25N with 1 to 3 ft seas. Relatively warm, moist SE flow over cooler shelf waters along the north Texas coast are supporting the potential for sea fog this morning. A surface trough is analyzed in the Bay of Campeche near 18N93W to 22N96W. Elsewhere, no significant weather is observed. For the forecast, the ridge will extend across the northern Gulf Through Fri. A trough will form off the west coast of the Yucatan Peninsula tonight, supporting brief pulses of fresh to strong winds. A cold front will move over the northern Gulf Sat and become stationary into Sat night. The western part of the front will begin to lift north as a warm front late Sat night through Sun, while the rest of the front dissipates as Atlantic high pressure builds westward across the area through Sun night. CARIBBEAN SEA... A tight gradient due to high pressure north of the area is supporting moderate to fresh NE winds in the eastern and central and winds to gale force continue north of Colombia through mid morning. Fresh trade winds persist over the eastern Caribbean. Seas are 8 to 13 ft over the southwest Caribbean due in part to NE to E swell. Seas are reaching 8 ft off Belize and Quintana Roo due to the long fetch of fresh NE winds from the Cuban coast. 5 to 7 ft seas are noted elsewhere. Regional radar suggests scattered showers persist in the trade wind flow across the eastern Caribbean. For the forecast, high pressure north of the area is supporting Fresh to strong winds and building seas over the southeast and south-central Caribbean, with winds pulsing to gale force off the coast of Colombia tonight. Fresh to strong northeast winds are also expected in the lee of eastern Cuba through tonight. Winds and seas diminish Thu through Sat as the high pressure weakens, although strong winds will persist off Colombia that could reach near gale force Thu night. ATLANTIC OCEAN... West of 60W: A cold front reaches from 30N48W to 25N60W, then is stationary to the southern Bahamas. Scattered showers are noted along the front and scattered moderate north of 28N. Farther west, a surface ridge extending west to east along roughly 28N is supporting moderate to fresh NE winds with 5 to 7 ft seas in open waters south of 25N, and gentle to moderate winds and 4 to 6 ft seas north of 25N, except 2 to 5 ft north of the northern Bahamas and off the northeast Florida coast. No significant shower activity is evident. For the forecast, a stationary front extending from near 24N65W to the Turks and Caicos will dissipate tonight. A new cold front will move southward into waters between northeastern Florida and Bermuda. The main portion of this front will lift to the northeast of the area Thu, leaving a trailing stationary segment to dissipate along 27N by Thu evening. This front will be followed by yet another cold front that will move southward across the waters between Bermuda and NE Florida late Fri, reach from near 31N60W to 27N70W and to West Palm Beach, Florida Sat night, then begin to weaken as it reaches the far southern waters late Sun. High pressure will build over the area in the wake of this front. Farther east, a 1025 mb high pressure centered near 27N30W is supporting moderate to fresh NE to E trade winds south of 25N where seas are 7 to 9 ft in a mix of N swell and shorter period wind waves. NW swell is reaching as far south as 30N between 45W and 65W, but 4 to 6 ft seas are noted elsewhere north of 25N. A sharp upper trough reaches from the Canary Islands to near 09N41W. Upper divergence southeast of the upper trough is supporting moderate showers within 480 nm to the southeast of the upper trough.