000 AXNT20 KNHC 201734 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Tue Aug 20 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 1630 UTC. ...TROPICAL WAVES... A newly analyzed tropical wave is off the Africa coast along 19W-20W, from 26N southward, and moving west 5 to 10 kt. Precipitable water animations suggest that the northern portion of the wave is along 20W, with a small cluster of moderate convection just ahead of it. The southern portion of the wave is still along the African coast. Scattered moderate convection is seen from 04N to 14N between 22W and the African coast. An Atlantic tropical wave is near 54W from 22N southward, and moving west around 15 kt. Recent ASCAT data suggests a broad surface trough in the vicinity along 57W-58W, south of 18W. No significant convection is associated with this wave. A Caribbean tropical wave is along 74W from the Windward Passage southward to the coast of Colombia, moving west around 15 kt. No convection and minimal cyclonic curvature are noted with this wave. A western Caribbean tropical wave has been relocated to 84W-85W from just south of the Yucatan Channel southward across Honduras and into the East Pacific, based on extended precipitable water animations. It is moving west at 15 kt. Weak surface troughing lingers from the Gulf of Honduras northward to the entrance to the Yucatan Channel. Widely scattered moderate convection dots the northwest Caribbean waters from 15N to 21N between 81W and 89W. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic at 23.5N16W, then runs southwestward across 15N28W to 16N34W to near 15N43.5W. Widely scattered moderate convection is noted near the trough from 09N to 12N between 25W and 43W. The eastern end of the East Pacific monsoon trough is generating scattered to numerous moderate to strong convection across the Caribbean waters Panama and Costa Rica from 11.5N southward and into the Eastern Pacific. ...GULF OF MEXICO... A weak cold front extends from the Florida Big Bend to near 27N90W, then becomes stationary to southwest Louisiana. Convection along the front has become insignificant in recent hours. To the south of the front, a surface trough, or convergence zone, extends from 27N82.5W to 23.5N94W Scattered moderate isolated strong convection with within 90 nm either side of this boundary between the central Florida coast and 91W. The Yucatan nocturnal trough has drifted westward to the central Bay of Campeche. Associated convection has ended along this feature. Weak cyclonic flow surrounds all of these features, producing mainly gentle to light winds and seas of 1 to 3 ft across most of the basin. Gentle to moderate SW to W winds prevail across the eastern and southeastern Gulf, south of the trough. Buoy observations show seas of 3 to 4 ft across the coastal waters in this area. For the forecast, the cold front over the NE Gulf will push E today while a stationary front will linger over the north-central Gulf through Thu. Showers and thunderstorms will persist over the Gulf during the next few days. Gentle to locally moderate winds and slight seas are expected through the end of the week. ...CARIBBEAN SEA... The Atlantic ridge extends from the NE Atlantic SW to the central Bahamas. This ridge extends north of the basin along 26N-27N, and continues to support a typical trade-wind regime across most of the Caribbean Sea. Refer to the Tropical Waves and Monsoon Trough/ITCZ sections for convection in the basin. A tight pressure gradient exists between the ridge, between the two tropical waves, and lower pressure over northwestern Colombia, and is sustaining fresh to strong ENE to E winds and seas of 7 to 1 ft across the south-central basin, per recent altimeter data. Moderate to fresh E winds and 5 to 7 ft seas are noted at the north-central basin. Light to gentle winds and seas at 1 to 3 ft exist at the lee of Cuba, and near Costa Rica and Panama. Gentle to moderate ENE to E winds and 3 to 5 ft seas prevail elsewhere in the Caribbean Sea, including the Gulf of Honduras. For the forecast, fresh to strong trades and moderate to rough seas will continue over the south-central basin through Wed as a strong pressure gradient between the Colombian low and a central Atlantic ridge persists. Elsewhere, moderate to locally fresh E to NE winds and slight to moderate seas are expected over the rest of the Caribbean this week. Light to gentle winds with slight seas will prevail over the NW Caribbean. ...ATLANTIC OCEAN... Please read the Ocean Prediction Center High Seas Forecast at website: https://www.ocean.weather.gov/shtml/NFDHSFAT1.php and advisories issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/cyclones/ for the latest information on recently downgraded Tropical Storm Ernesto in the north Atlantic. A surface trough, convergence zone, persists across the NW Atlantic waters, from offshore of central Florida near 29N79W to near 31N73W. Moderate S to SW winds extend from the trough southward to 24N. A deep-layered upper trough moving slowly southeastward across the east and southeastern U.S. is supporting scattered moderate isolated strong convection within 180 nm SE of the trough east of 78W. A well established TUTT extending along the southern boundary of the Atlantic ridge is combining with the ridge to maintain relatively fair weather across the basin, north of 20N. Refer to the Tropical Waves and Monsoon Trough/ITCZ sections for additional weather in the Atlantic Basin. A broad surface ridge extends southwestward from a 1028 mb Azores High near 44N27W to the central Bahamas. This ridge is maintaining gentle to moderate with locally fresh SE to SW winds with 4 to 5 ft seas 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 7 to 9 ft dominate north of 22N between the northwest Africa coast and 30W. Near the Cabo Verde Islands, light to gentle W to NW winds and seas of 4 to 6 ft in mixed moderate swells are present from 08N to 22N between the central Africa coast and 30W. For the tropical Atlantic from 08N to 20N between 30W and the Lesser Antilles, gentle to moderate NE to E winds and 5 to 7 ft seas exist. Gentle with locally moderate S to SW winds and seas of 5 to 7 ft in mixed moderate to large swells prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, moderate to locally fresh SW winds will occur off the coast of northeast Florida today before a weak cold front moves east of the region on Wed. Moderate to locally fresh trades and slight to moderate seas will occur across much of the basin this week. $$ Stripling