000 AXNT20 KNHC 121024 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Mon Jul 12 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1010 UTC. ...TROPICAL WAVES... An Atlantic tropical wave is along 36W from 12N southward and moving W at 15 to 20 kt. Scattered moderate convection is seen from 07N to 10N between 35W and 37W. Another weaker Atlantic tropical wave is near 47W from 11N southward and moving W near 15 kt. No significant convection is found near this wave. A robust Caribbean tropical wave extends from Haiti to northeast Colombia, moving W at 10 to 15 kt. Aided by upper- level divergent winds, scattered to numerous showers and thunderstorms are present across the Turks and Caicos Islands, Dominican Republic and the northeastern Caribbean south of Puerto Rico and the Virgin Islands. Another Caribbean tropical wave over Honduras, Nicaragua and Costa Rica is moving W at 10 to 15 kt. No significant convection is observed over the Caribbean associated with this tropical wave. This wave is entering the E Pacific and will be included in the Pacific Discussion. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the African coast near the Senegal/Guinea-Bissau border at 12N16W to 08N30W to 07N35W. The ITCZ then continues from 07N35W to 07N45W. In addition to the convection listed in the Tropical Wave section, scattered moderate to isolated strong convection is evident near the monsoon trough from 06N to 14N between 15W and 30W, and from Scattered moderate convection is evident from 07N to 10N between 40W and 45W. ...GULF OF MEXICO... A surface ridge extends west-southwestward from northern Florida across the northern Gulf to South Texas. This pattern is supporting mostly gentle to moderate E to SE winds over the basin, except for fresh NE to E winds over the eastern Bay of Campeche and off the west coast of the Yucatan Peninsula. Seas are 2 to 4 ft in most areas, except 3 to 5 ft in the eastern Bay of Campeche. A few showers and thunderstorms are noted over the Straits of Florida, and over the warmer Loop Current of the south-central Gulf. No other significant shower or thunderstorm activity is evident at this time across. For the forecast, the gentle to moderate SE winds will persist across most of the Gulf, south of the surface ridge. The ridge will lift just north of the area through today, maintaining gentle to moderate winds and slight to moderate seas through Fri. The exception will be fresh to occasionally strong winds off the northwest Yucatan Peninsula and eastern Bay of Campeche during overnight hours through mid week, related to the surface trough that forms during the late afternoon each day. ...CARIBBEAN SEA... Please refer to the Tropical Waves section above for details on convection in the basin. Scatterometer data from 0430 UTC depicted fresh to strong trade winds across the south-central Caribbean, as well as over the Gulf of Honduras and into the northern approaches of the Windward Passage, where concurrent altimeter data showed wave heights near 8 ft. Maximum seas are estimated to be 9 ft in the south-central Caribbean, mainly off the coast of Colombia, and to 8 ft over the eastern Caribbean where fresh tradewinds follow the tropical wave moving across the basin. Moderate E to SE winds and 3 to 5 ft seas are noted over the northwest Caribbean. In addition to the convection mentioned in the Tropical Wave section, scattered moderate to isolated strong convection is ongoing off eastern Panama. For the forecast, the tropical wave reaching from Haiti to northeast Colombia will move quickly across the central Caribbean through today, and then move west of the basin into mid week. High pressure centered north of the region will build in the wake of the tropical wave, supporting strong tradewinds and building seas into Wed, including strong nocturnal NE winds across the Windward Passage Tue night into Wed. Winds and seas will diminish through Fri. ...ATLANTIC OCEAN... Please see the Tropical Waves and Monsoon Trough/ITCZ sections above for information on convection across the basin. A surface ridge extends from the central Atlantic across Bermuda to the central Florida coast. This pattern is supporting mostly moderate to fresh tradewinds south of 25N west of 35W with 6 to 9 ft seas, and gentle to moderate E to SE winds north of 25N west of 35W with 3 to 5 ft seas over open waters. Strong E winds are noted of Hispaniola toward the approaches to the Windward Passage, with seas near 8 ft. Divergence aloft associated with an upper low now centered over Grand Bahama Island is supporting clusters of scattered moderate to isolated strong convection over the Cay Sal area of the Bahamas and across the southern Bahamas and Turks and Caicos Islands. For the forecast, the surface ridge will lift northward to along 32N through Tue. The tropical wave over Haiti will move quickly westward across the central Caribbean and bring a surge in wind and waves to the Atlantic waters north of Hispaniola and Cuba and across the Turks and Caicos Islands and southern Bahamas late today and Tue. Strong winds will continue to pulse off Hispaniola and into the Windward Passage Tue night into Wed. Winds and seas will diminish across the region through Fri as the high pressure weakens. Farther east, north of 27N east of 35W, fresh to strong NE winds and 5 to 8 ft seas are following a westward moving trough analyzed from 25N to 30N between 35W and 38W. South of 27N east of 35W gentle to moderate N to NE breezes and 3 to 5 ft seas are evident. $$ Christensen