000 AXNT20 KNHC 121759 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sat Aug 12 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 29W from west of the Cabo Verde Islands at 16N southward, and moving west around 15 kt. Scattered moderate convection is noted from 07N to 10N between 24W and 33W. A western Atlantic tropical wave is relocated to 59W near Barbados from 20N southward, based on 12Z sounding data from Guadeloupe and Barbados. It is moving west around 15 kt. Widely scattered showers and isolated thunderstorms are noted near the Lesser Antilles. A western Caribbean tropical wave is near 82W from near the Cayman Islands southward, and moving west around 20 kt. Scattered showers and isolated thunderstorms are occurring over southern Cuba and nearby waters, and across the southwestern Caribbean Sea. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through the coast of Gambia, then extends southwestward across 10N27W to 07N34W. Besides the convection related to the tropical wave mentioned in the above section, scattered to numerous moderate convection is seen from 07N to 13N between the Guinea/Sierra Leone coast and 24W. An ITCZ continues westward from 07N34W to 07N46W. Widely scattered showers are found near and up to 90 nm south of the ITCZ. ...GULF OF MEXICO... A surface trough is triggering widely scattered showers at the Bay of Campeche. Otherwise, a broad surface ridge along with a 1017 mb high at the northeastern Gulf are dominating much of the region. Light to gentle winds and seas of 1 to 2 ft are present over the eastern and north-central Gulf, including the Florida Straits. Gentle to moderate E to SSE winds and 2 to 4 ft seas prevail elsewhere in the Gulf, including the Bay of Campeche. For the forecast, a trough will move off the Yucatan Peninsula each night, supporting fresh winds off northwest Yucatan. Elsewhere, the high and related ridge over the northern Gulf will support mostly gentle to moderate winds and slight seas across the region into mid week. ...CARIBBEAN SEA... An upper-level low in the eastern basin near 16N68W is producing widely scattered showers and isolated thunderstorms from Curacao northward to Puerto Rico. Refer to the Tropical Waves section above for additional weather in the Caribbean Basin. The Atlantic Ridge to the north near 28N continues to sustain a trade-wind regime across much of the basin, except near Costa Rica and Panama. Fresh to strong ENE to E winds and seas of 6 to 9 ft exist across the central basin. Gentle to moderate E to ESE winds and 2 to 4 ft seas are noted at the northwestern basin, including the Gulf of Honduras. Light to gentle monsoonal winds and seas at 3 to 6 ft in moderate easterly swell are present near Costa Rica and Panama. Moderate to fresh easterly winds and 4 to 7 ft seas prevail for the rest of the basin. For the forecast, fresh to strong winds and rough seas over the south-central Caribbean will expand across much of the central and southwest Caribbean through late today as the Atlantic Ridge strengthens. Except for fresh to strong winds over the Gulf of Honduras Sun night, these winds and seas will diminish slightly into early next week over most of the basin as a trough moving into the Bahamas weakens the ridge. Looking ahead, winds and seas will increase again over the south-central Caribbean as the Atlantic Ridge strengthens again. ...ATLANTIC OCEAN... A surface trough is causing scattered showers and isolated thunderstorms at the Great Bahama Bank, and the central and northwest Bahamas. An upper-level trough runs northward from near the Windward Passage to south of Bermuda. Interaction with convergent southerly winds is causing scattered moderate convection north of 27N between 67W and the Georgia-Florida coast. Another surface trough extends southwestward from the north- central Atlantic across 31N44W to northeast of Puerto Rico near 22N63W. This feature is generating widely scattered moderate convection from 21N to 28N between 57W and 65W. Refer to the Monsoon Trough/ITCZ and Tropical Waves sections at the beginning for additional convection in the Atlantic Basin. An Atlantic Ridge extends southwestward from a 1026 mb high near 35N35W across 31N60W to near the central Bahamas. This ridge is supporting light to gentle winds and seas of 4 to 6 ft in moderate northerly swell north of 27N between 45W and the Georgia-Florida coast. For the eastern Atlantic, moderate to fresh with locally strong NNE to NE trades and seas of 7 to 10 ft dominate north of 21N between the Africa coast and 45W, including the Canary Islands. For the tropical Atlantic, gentle to moderate with locally fresh NE to E trades and 5 to 7 ft seas are evident from 10N to 20N between 32W and the Lesser Antilles. Near the Cabo Verde Islands, light to gentle monsoonal winds with seas at 4 to 6 ft are noted from 10N to 21N between the central Africa coast and 32W. Gentle to moderate southerly winds and seas of 6 to 8 ft in moderate southerly swell prevail for the remainder of the Atlantic Basin. For the forecast W of 55W, the Atlantic Ridge will lift northward today ahead of the surface trough moving westward toward the Bahamas through early next week. Expect moderate to fresh easterly winds south of 24N following the trough Sun to Tue. Fresh to strong winds will pulse off Hispaniola during the late afternoons and early evenings through Tue. $$ Forecaster Chan