000 AXNT20 KNHC 171756 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sat Apr 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: As of 1200 UTC, a cold front and an attendant 1008 mb low moved off the Texas coast into the Gulf of Mexico. The front will move southward across the basin bringing strong winds and building seas. An area of gale force northerly winds is expected to develop offshore of the Tampico area tonight, behind the front. Seas will build to 12 ft in that area, before winds and seas diminish beginning Sunday morning. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at the website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic ocean through the coast of Guinea-Bissau in West Africa near 10N15W and continues southwestward to 02N25W. The ITCZ continues from 02N25W to the coast of Brazil in South America near 00N47W. Scattered moderate to strong convection is seen 400 nm south of the monsoon trough between 10W-20W. Scattered showers are noted in the vicinity of the ITCZ. GULF OF MEXICO... Please see the Special Features section for details on the Gale Warning in effect for the west-central Gulf of Mexico. As of 1545 UTC, a nearly stationary front over the Florida Peninsula transitions to a warm front near 29N86W and connects with a 1010 mb low south of the Louisiana coast near 29N91W. To the southwest, a cold front extends southward to near Tampico, Mexico. Scattered showers and isolated thunderstorms are located behind the front extending from South Texas northeast to central Louisiana near 29N90W. In the Bay of Campeche, an area of low pressure is centered near 21N96W with a surface trough extending from 22N94W to 19N97W. Scattered showers are noted in the vicinity of the surface trough. Fresh to strong with few gusts to gale force winds are occurring along the Texas coast behind the front, with generally moderate SE winds elsewhere. Seas ranged between 2 to 6 ft across the basin. A cold front currently moving across the Texas coastal waters will reach from near Panama City, Florida to 23N95W to the far southwest Bay of Campeche by this evening. Winds will briefly reach gale force near Tampico, Mexico tonight west of the front. The front will stall from near Tampa Bay, Florida to the central Bay of Campeche by early next week. Looking ahead, reinforcing cool and dry air will push the front into the far southeast Gulf through mid-week. CARIBBEAN SEA... Current satellite imagery shows very little of ash cloud from the latest eruption of La Soufriere volcano on Saint Vincent yesterday morning. The ashfall advisory for the Caribbean waters west of the Windward Islands has been allowed to expire. Additional eruptions are possible at any time. The volcano remains in a continually active state, and additional eruptions and ash plumes are possible at any time. Mariners transiting the nearby waters should exercise caution, and are encouraged to report volcanic ash to the National Hurricane Center by calling 305-229-4424. Fresh trade winds prevail over the south-central and eastern Caribbean, with moderate trades in the north central Caribbean. Scatterometer data reveals an area of fresh to strong SE winds offshore of Honduras and Belize, with moderate SE winds elsewhere in the northwest Caribbean. Seas of 3-6 ft are over most of the basin, except near the Gulf of Honduras with seas near 8 ft and seas up to 7 ft north of Venezuela near the ABC Islands. For the forecast, a ridge extends along 23N through western Cuba. Fresh to strong SE winds will persist north of central Honduras through Sun, between the ridge and lower pressure over the southwest Gulf of Mexico. The ridge will shift east ahead of a weak front moving into the Gulf allowing trade winds to increase over mainly the south-central Caribbean early next week. ATLANTIC OCEAN... A slowing cold front extends from a 1010 mb low pressure near 31N73W to 29N76W, where it transitions to a stationary front to a second area of low pressure near Floridas Big Bend. Thunderstorms continue within 120 nm of the Florida coast, along this boundary. A cold front extends southwest to the low southwest of Bermuda and remains north of 29N. At this time, scattered showers are seen out to 100 nm on either side of the boundary. Winds are moderate and W to the W of 70W with seas 3-5 ft. Elsewhere, ridging from high pressure dominates supporting gentle to moderate anticyclonic flow north of 20N and west of 55W. Winds south of 20N are mainly fresh to locally strong southeasterlies with seas 6-8 ft. Seas north of 29N range from 7-9 ft. A surface trough is noted from 29N37W to 23N55W, with scattered moderate convection from 21N-26W between 45W to 56W. For the forecast, the boundary will fluctuate to the north and south over the waters between roughly Bermuda and northeast Florida through early next week, as a ridge persists across the central Bahamas. Looking ahead, the ridge will shift east by mid-week ahead of a slightly stronger frontal boundary moving off the southeast U.S. coast by late Wed. Torres/Christensen