000 AXNT20 KNHC 211804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 34W from 19N southward, and moving westward at 5 to 10 kt. Scattered moderate convection is noted from 07N to 10N between 33W and 36W. A western Caribbean tropical wave is near 80W from the Cayman Islands southward across central Panama to the East Pacific. It is moving westward around 15 kt. Scattered showers and isolated thunderstorms are occurring near the Cayman Islands, and along the coast of Nicaragua, Costa Rica and Panama. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through the Mauritania coast near Nouakchott, then extends southwestward across 12N30W to 10N43W. An ITCZ continues westward from 10N43W to north of Guyana near 09N58W. Scattered moderate convection is noted south of the trough from 07N to 11N between the Guinea/Sierra Leone coast and 23W, and near the trough from 07N to 10N between 36W and 42W. Widely scattered moderate convection is noted up to 70 nm along either side of the ITCZ between 51W and 58W. ...GULF OF MEXICO... A surface trough reaches northeastward from near Corpus Christi, Texas to beyond New Orleans, Louisiana. An upper-level trough runs northeastward from a low near Tampico, Mexico to beyond the Texas/Louisiana coastal border. Interaction between these features is triggering scattered showers and isolated thunderstorms across the northwestern, north-central and southwestern Gulf, including the Bay of Campeche. A modest 1018 mb high over the northeastern Gulf supports light to gentle winds and 1 to 2 ft seas there. Gentle to moderate ESE to S winds with seas at 2 to 4 ft prevail for the rest of the Gulf. For the forecast, the aforementioned high and related ridge will remain across the northeastern and southwestern Gulf over the next several days. It will support gentle to moderate E to SE winds and slight seas. Pulsing moderate to fresh winds are expected near and northwest of the Yucatan Peninsula during the evening and nighttime hours due to local effects. Scattered to numerous showers and thunderstorms are expected over the Straits of Florida and the southeastern Gulf tonight and Mon as the northern portion of a tropical wave moves across the area. ...CARIBBEAN SEA... Refer to the Tropical Waves section for convection in the Caribbean Sea. A large 1026 mb Bermuda High near 32N59W sustains a trade-wind pattern across much of the basin. Tighter gradient between this feature and lower pressure over northern Colombia is causing fresh to strong easterly winds and seas of 7 to 9 ft at the central basin. Light to gentle winds with 2 to 4 ft seas in E swell are present near Costa Rica, Panama and northwestern Colombia. Gentle to moderate ENE to ESE winds and seas at 3 to 6 ft prevail elsewhere in the Caribbean Basin, including the Gulf of Honduras, Windward and Mona Passages. For the forecast, the aforementioned tropical wave will move through the western basin tonight and Mon. High pressure from the central Atlantic will build in its wake, with increasing fresh to strong winds and building seas, possibly peaking to 11 or 12 ft over the south-central basin early on Mon. The trade winds and associated seas will diminish slightly on Tue, then increase across the eastern and central basin through midweek. ...ATLANTIC OCEAN... An upper-level trough extends southwestward from a low southwest of Bermuda near 29N68W to another upper-level low near central Cuba. Divergent winds between these lows are coupling with a surface trough over the central Bahamas to produce scattered showers and thunderstorms from 22N to 27N between 72W and 79W, including the central Bahamas and Great Bahama Bank. Divergent winds related to another upper- level low near 30N24W are inducing isolated thunderstorms north of 26N between 32W and 39W. Refer to the Tropical Waves and Monsoon Trough/ITCZ sections for additional weather in the Atlantic Basin. Fresh with locally strong SE winds and 5 to 7 ft seas are evident near the southeast and central Bahamas. Otherwise, a combination of the 1026 mb Bermuda High and 1025 mb Azores High is supporting gentle to moderate ENE to SSE winds and seas of 4 to 6 ft exist north of 20N between 30W and the Florida-Georgia coast. Near the Canary Islands, moderate to fresh with locally strong NNE to NE winds and seas at 6 to 8 ft are noted north of 20N between the northwest Africa coast and 30W. Farther south from 08N to 20N between the central Africa coast and 30W, gentle to moderate with locally fresh W to NW to N winds with 4 to 7 ft seas are present, including the Cabo Verde Islands. For the tropical Atlantic from 10N to 20N between 30W and the Lesser Antilles, gentle to moderate NE to E winds and seas of 4 to 6 ft are observed. Gentle to moderate with locally fresh southerly winds and seas at 3 to 6 ft in mixed moderate swells prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, the Bermuda-Azores high combo will continue to dominate the Atlantic over the next several days. The related pressure gradient will support moderate to fresh easterly winds south of 25N, with winds pulsing to strong during the late afternoons and evenings off the northern coast of Hispaniola through at least midweek. The northern portion of a tropical wave combined with an upper-level low near central Cuba is resulting in scattered to numerous showers and thunderstorms over portions of the Bahamas and the waters between the central Bahamas and Cuba. This convective activity will continue to shift westward across the Bahamas, western Cuba, and the Great Bahama Bank today, reaching the Straits of Florida tonight. Some of the stronger thunderstorms may produce strong gusty winds and rough seas. $$ Chan