814 AXNT20 KNHC 102319 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Aug 11 2023 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 2300 UTC. ...SPECIAL FEATURES... Gale Warning E of 35W: The pressure gradient between a 1024 mb high pressure located north of the Madeira Islands and lower pressures in NW Africa supports gale force winds, with severe gusts in the water passages between the Canary Islands. Latest scatterometer data confirmed the presence of these winds. Meteo- France has a Gale Warning in effect until 11/0600 UTC. For more details, refer to the Meteo-France High Seas Forecast listed on their website https://wwmiws.wmo.int ...TROPICAL WAVES... An eastern Atlantic tropical wave is located near 25W, south of 17N, and is moving westward at around 10 kt. Scattered moderate convection is noted ahead of the wave axis from 06N to 09N between 25W and 28W. A central Atlantic tropical wave is located near 40W, south of 17N, and is moving westward at around 10 kt. Scattered showers are near the southern end of the wave axis. A tropical is moving across the eastern Caribbean with axis along 68W south of 20N, moving W at 15 to 20 kt. The wave is helping to induce numerous showers and thunderstorms over Hispaniola and regional waters, as well as over western Venezuela. A second tropical wave is moving across the central Caribbean. Its axis is along 79W south of 21N, moving W at 10 kt. The wave appears to enhance convection over eastern Cuba, Jamaica and the Cayman Islands. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near Dakar, Senegal and continues SW then westward to 11N20W to 08N35W to 08N47W. The ITCZ extends from 08N47W to 10N60W. Please refer to the Tropical Waves section above for convection in the area. GULF OF MEXICO... A ridge dominates the Gulf waters producing gentle to moderate winds with the exception of moderate to locally fresh E winds just N of the Yucatan Peninsula. Seas are 3-4 ft W of 90W and 1-3 ft E of 90W. Scattered showers and thunderstorms are noted over the NE Gulf and northern Florida while numerous showers with embedded thunderstorms are occurring over central and south Florida where a diffluent pattern aloft is noted. For the forecast, surface ridging across the Gulf will support gentle to moderate winds over most of the basin during the next several days. Moderate to fresh winds will pulse over the western Gulf with slight to moderate seas. A thermal trough will move off the Yucatan Peninsula each night and produce fresh to strong winds off NW Yucatan. CARIBBEAN SEA... Satellite derived wind data provide observations of moderate to fresh winds over the NE and central Caribbean, in the Windward Passage and in the Gulf of Honduras. Gentle to moderate winds prevail elsewhere. Seas are 3-5 ft across the E and central Caribbean and 2-4 ft over the NW Caribbean. Late this afternoon, convection has flared up mainly over Hispaniola, eastern Cuba and Jamaica due to the passage of a couple of tropical waves. For the forecast, moderate to fresh winds will prevail in the central and eastern Caribbean as a tropical wave moves across the area through Fri, locally strong in the south-central portion. Light to gentle winds can be expected for the western part of the basin. On Fri night through Tue night, fresh to strong winds and moderate seas will expand across the central Caribbean, while moderate to fresh winds and moderate seas prevail elsewhere. ATLANTIC OCEAN... A ridge dominates most of the Atlantic forecast waters with a 1024 mb high pressure located N of the Madeira Islands near 37N15W, and a second and weaker high pressure center of 1019 mb situated near 27N61W. A stationary front is between these high pressure centers and extends from 31N40W to 26N52W. A few showers are near the southern end of the frontal boundary. An upper-level low over the SE Bahamas is generating scattered showers and thunderstorms. Similar convective activity is NE of Hispaniola affecting mainly the waters from 19N to 23N between 66W and 70W. Saharan dust is noted over most of the tropical Atlantic reaching the NE Caribbean based on the Saharan Air Layer tracking product from CIMSS. Moderate to locally fresh NE winds are evident over the Cabo Verde Islands while gentle to moderate trades are noted over the remainder of the tropical Atlantic. Light to gentle winds are associated with the aforementioned ridge. Seas are 6-8 ft E of 22W, and 4 to 6 ft elsewhere E of the Bahamas. For the forecast W of 55W, the subtropical ridge axis will continue to be situated near 28N through the weekend and into early next week. The northern portion of a tropical wave is expected to move across the southeastern waters through Fri. This will increase winds fresh to locally strong with moderate seas across the region, including the Bahamas. Moderate to fresh winds will resume on Sat. Winds will pulse fresh to locally strong north of Hispaniola during the evenings Sat through Tue. $$ GR