000 AXNT20 KNHC 252229 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Nov 26 2024 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 1800 UTC surface analysis and satellite imagery through 2220 UTC. ...SPECIAL FEATURES... Long-Period NW Swell in the Atlantic: Long-period NW swell with 12 ft seas continue to propagate across the north-central Atlantic subtropical waters in the wake of a stationary front that extends from 31N45W SW to the Windward Passage. The front will remain stationary while weakening and merging with a reinforcing cold front tonight into Tue. A second set of long-period NW swell will follow the reinforcing front and propagate across the north- central and northeastern Atlantic subtropical waters with 12-16 ft seas through Thu. Please read the latest HIGH SEAS FORECAST, that is issued by the National Hurricane Center, at the website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for details. Excessive Rainfall in the North Caribbean: The combination of an upper-level trough extending from the FL Peninsula into the Gulf of Honduras, a dissipating stationary front in the Windward Passage, and a surface trough extending from the Windward Passage southward to the coast of Panama where a 1010 mb surface low is also forming on the eastern extension of the East Pacific monsoon trough, all are favoring moisture convergence near the Haitian Peninsula. Numerous moderate to strong convection is occurring as a result. These features will be slow to move and evolve over the next 2-3 days, which will favor multiple rounds of heavy rain. Heavy precipitation looks to occur from Haiti into the Bahamas and Turks and Caicos today through early Wednesday, while Haiti and Jamaica may see heavy rain continue through Thursday. This extended period of heavy rain will increase risks for flash flooding as well as mudslides and landslides. This information was provided by the International Desks Team at WPC. Please refer to them and local meteorological agencies for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic from the coast of Sierra Leone near 08N13W and continues to 06N15W. The ITCZ then continues from 06N15W to 03N25W to 04N48W. Scattered moderate convection is ongoing from 04N to 08N between the west coast of Africa and 35W. ...GULF OF MEXICO... The subtropical ridge extends across the western Atlantic to 1022 mb high pressure centered over the Big Bend area of Florida. The ridge then extends to 1023 mb high pressure centered near Veracruz Mexico. Gentle to moderate S winds are noted over the western Gulf with 2 to 5 ft seas, and gentle to moderate NE to E winds are evident across the Straits of Florida where seas are 2 to 4 ft. Light breeze and slight seas are noted elsewhere. For the forecast, the ridge will prevail across the Gulf waters through Thu. Moderate to locally fresh southerly winds will persist over the western Gulf before diminishing briefly ahead of a weak cold front forecast to move off the coast of Texas tonight into Tue. The front will extend along the northern Gulf through Tue, then move NE of the area Tue night. Another cold front is expected to enter the NW Gulf waters by late Thu morning. Moderate to fresh southerly winds will once again develop over the western Gulf Tue night through Wed night ahead of the second front, which will reach from Cedar Key, Florida to near Tampico, Mexico early on Fri, and from the Straits of Florida to near Veracruz, Mexico Fri night. The front will exit the basin on Sat. Fresh to strong northerly winds and building seas will follow this front. Winds may briefly reach minimal gale force near the Veracruz area on Fri. ...CARIBBEAN SEA... Please see the Special Features section above for details on heavy rainfall affecting the Northern Caribbean. A surface trough extends from the Windward Passage southward to the coast of Colombia, near where a 1010 mb surface low is also forming on the eastern extension of the East Pacific monsoon trough north of Panama. Numerous moderate and isolated strong convection is occurring from 12N to 17N between 74W and 80W. Scattered moderate convection is also occurring across the SW Caribbean from 12N to 17N between 68W and 72W. Outside of convection, much of the Caribbean is under the influence of high pressure interacting with a developing low in the Caribbean, with fresh to strong E winds across the central Caribbean, moderate to fresh E winds in the eastern Caribbean, and gentle to moderate E winds across the western basin. Seas are moderate across much of the basin. For the forecast, a tightening pressure gradient between developing low pressure in the SW Caribbean and high pressure building over the SW N Atlantic will support fresh to strong NE winds in the Windward Passage, and fresh to strong NE to E winds across the central Caribbean today. Moderate to locally fresh trades are forecast basin-wide the remainder of the forecast period, except in the lee of eastern Cuba where fresh to locally strong NE winds are predicted beginning on Tue as a low pressure develops in the vicinity of the SE Bahamas. The low pressure will open up into a trough on Thu while winds diminishing in the lee of Cuba. ...ATLANTIC OCEAN... Please read the Special Features section for details about long period swell affecting the northern Tropical Atlantic. The subtropical ridge covers the region north of 15N, anchored by 1022 mb high pressure northeast of the Bahamas near 28N69W, and 1020 mb high pressure near 27N37W. The ridge is broken only by a frontal boundary reaching from the Azores to the Windward Passage, and the front is stationary south of 30N. Scattered showers and thunderstorms are active south of 25N between 65W and 75W, including Hispaniola, the southern Bahamas, and the Turks/Caicos Islands. Moderate to fresh trade winds are noted south of 22N west of 50W, with gentle to moderate trade winds farther east over the deep tropics. Mostly light to gentle breezes are noted elsewhere, under the influence of the subtropical ridge. The aforementioned NW swell of 8 to 12 ft is mainly west of the frontal boundary to 65W, north of 22N. Wave heights are 5 to 7 ft in a mix of swell elsewhere, except 2 to 5 ft north of the Bahamas. For the forecast west of 55W, the stationary front will remain nearly stationary through Tue, then lift northward on Wed as a low pressure develops over the SE Bahamas. The low pressure will open up into a trough over the central Bahamas and eastern Cuba on Thu while the front gradually dissipating. The next cold front will enter the NE Florida offshore waters Tue night before stalling and lifting N of the area late Wed. A stronger cold front is forecast to move offshore NE Florida on Fri. Fresh to strong winds and building seas are expected on either side of the front. $$ Christensen