981 AXNT20 KNHC 202208 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Jul 21 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 2200 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 31W from 20N southward, and moving westward at 15 to 20 kt. No significant convection is noted near this tropical wave. A central Caribbean tropical wave is near 77W from eastern Cuba and Jamaica southward into eastern Panama. It is moving westward at near 20 kt. Scattered showers and thunderstorms are occurring between Jamaica and eastern Cuba. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through the coast of Mauritania near 19N16W, then extends southwestward to 09N50W. An ITCZ continues westward from 09N50W to 10N60W. Saharan dust is suppressing any significant convection. ...GULF OF MEXICO... A surface trough reaches across the northwest Gulf from Vermilion Bay, Louisiana, to off South Padre Island, Texas. Scattered showers and thunderstorms are active west of the trough, over much of the northern Gulf. The Atlantic ridge extends westward across Florida into the eastern Gulf. This pattern is supporting light to gentle breezes and slight seas across the basin. For the forecast, the ridge will remain in place across the Gulf waters over the next several days. It will support gentle to locally moderate E to SE winds and slight seas. Pulsing moderate to fresh winds are expected near and to the northwest of the Yucatan Peninsula during the evening and night hours due to local effects. Scattered to numerous showers and thunderstorms are expected over the Straits of Florida Sun night as a tropical wave passes to the south. ...CARIBBEAN SEA... The Atlantic high pressure is building over the eastern Caribbean following through tropical wave that extends from Jamaica to eastern Panama. This pattern is supporting fresh to strong trade winds off northwest Venezuela and northeast Colombia. Moderate to fresh trade winds are noted elsewhere over the eastern and central Caribbean. Gentle to moderate E winds are noted elsewhere over the basin. Combined seas are 5 to 7 ft in the central Caribbean, and 3 to 5 ft elsewhere. For the forecast, the tropical wave will move through the western Caribbean tonight through Mon afternoon. High pressure from the central Atlantic will continue to build in its wake, with fresh to strong winds and building seas, possibly peaking to 10 ft over the south-central Caribbean on Mon. The trade winds and associated seas will diminish slightly on Tue, then increase across the eastern and central Caribbean for the remainder of the forecast period. ...ATLANTIC OCEAN... An upper-level trough reaches southwestward from a low southeast of Bermuda near 30N66W across the central Bahamas to central Cuba. Divergent winds related these features are enhancing scattered showers and isolated thunderstorms along an associated surface trough moving through the southern Bahamas and Turks/Caicos Islands. At the surface, the pattern is dominated by 1028 mb high pressure centered near 32N57W. The gradient between the high pressure and the surface trough is supporting fresh to strong E to SE winds on the north coast of Hispaniola. Gentle to moderate E to SE winds are noted elsewhere across the basin west of 35W. Combined seas are 6 to 8 ft in E swell across Atlantic waters from 10N to 25N between 50W and 75W, 4 to 6 ft elsewhere west of 35W. Gentle to moderate NE winds persist east of 35W, except for fresh to strong winds off northwest Africa and the Canary Islands, with mostly 4 to 6 ft combined seas. For the forecast west of 55W, the Atlantic surface ridge will continue to dominate the Atlantic forecast waters through the weekend, then lift north to near 30N early next week. The related pressure gradient will support moderate to fresh easterly winds south of 26N, with winds pulsing to strong during the late afternoons and evenings off the northern coast of Hispaniola into next week. Numerous thunderstorms over the waters south of 25N between 68W and 74W are associated with an upper-level low and a surface trough while the northern portion of a tropical wave is over eastern Cuba. These features along with the thunderstorm activity will continue to shift westward reaching the waters between the Bahamas and Cuba, including the Straits of Florida late Sun into Mon. Some of the thunderstorms may produce strong gusty winds and rough seas. $$ Christensen