000 AXNT20 KNHC 112320 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 24W from the Cabo Verde Islands southward, moving westward at 5 to 10 kt. Scattered moderate convection is noted where the wave meets the monsoon trough from 08N to 10N between 20W and 26W. A central Atlantic tropical wave is near 47W from 18N southward, moving westward around 10 kt. Scattered moderate to isolated strong convection is near the southern end of the wave axis from 05N to 07N between 46W and 49W. A tropical wave is over the central Caribbean and extends from eastern Cuba to northern Colombia. Its with axis is along 76W, moving westward at 15 to 20 kt. Numerous showers, with embedded thunderstorms, are occurring over eastern Cuba and Jamaica. Scattered showers and thunderstorms are over northern Colombia. Moisture associated with this system will spread over central Cuba and the Cayman Islands tonight into Sat. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near the Mauritania-Senegal border, then extends southwestward to 11N24W to 09N38W. the ITCZ continues from 09N38W to 09N58W. Clusters of moderate to isolated strong convection are affecting the coasts of Guinea Bissau, The Gambia and Senegal. ...GULF OF MEXICO... A ridge dominates the Gulf waters producing moderate to locally fresh SE to S winds over the western Gulf, and gentle to moderate winds over the eastern Gulf. A 1017 mb high pressure is analyzed over the NE Gulf, while a surface trough, likely associated with the sea breeze convergent, is helping to induce some convective activity over Florida. Seas are generally 1 to 3 ft across the basin, with the exception of 3-4 ft near and to the W of the Yucatan Peninsula and in the central Bay of Campeche. For the forecast, expect moderate to fresh SE winds overnight across the west-central Gulf between high pressure over the northeast Gulf and lower pressure over central Mexico. A trough will move off the Yucatan Peninsula each night supporting fresh to occasionally strong winds off northwest Yucatan. Elsewhere, the ridge over the northern Gulf will support mostly gentle to moderate winds and slight seas across the basin into mid week. ...CARIBBEAN SEA... Satellite derived wind data provide observations of fresh to strong winds over the central Caribbean from 12N to 16N, with moderate to fresh trades elsewhere. Seas are 6-8 ft with the strongest winds. In the east and western Caribbean, mainly gentle to moderate winds prevail. Seas are 3-5 ft elsewhere across the E and central Caribbean, and 1-3 ft over the NW Caribbean. Late this afternoon, convection has flared up mainly over eastern Cuba and Jamaica due to the presence of a tropical wave. For the forecast, fresh to strong winds over the south-central Caribbean will expand across much of the central and southwest Caribbean through late Sat as high pressure builds north of the area. 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 high pressure. Looking ahead, winds and seas will increase again over the south-central Caribbean as high pressure builds over the western Atlantic early next week. ...ATLANTIC OCEAN... A ridge dominates most of the Atlantic forecast waters with a 1027 mb high pressure located near the Azores. A second and weaker high pressure center of 1021 mb is situated SE of Bermuda near 29N61W. A frontal trough is between these high pressure centers and extends from 31N42W to 25N54W. A few showers are near the southern end of the trough. Numerous showers and thunderstorms are seen over the central Bahamas and parts of the Old Bahama Channel as well as over the waters NE of the Bahamas, particularly from 23N to 27N between 71W and 76W. An upper-level trough exiting Florida is helping to induce this convective activity. Moderate to fresh winds are just N of Hispaniola while gentle to moderate winds prevails elsewhere W of 35W. Seas area generally 3-5 ft, except 5-7 ft between 35W and 40W. Fresh to strong winds are E of 35W, including between the Canary Islands based on scatterometer data. Seas are 7-9 ft within these winds according to altimeter data. An area of fresh to strong southerly winds is noted south of the monsoon trough between 20W and 27W where seas are in the 8-11 ft range. A new outbreak of Saharan dust was noted over the eastern Atlantic on Fri, while the Saharan Air Layer tracking product from CIMSS indicates that African dust is reaching the eastern Caribbean. For the forecast W of 55W, the subtropical ridge extends along 28N and will lift northward through Sat ahead of a surface trough moving westward toward the Bahamas through early next week. Expect moderate to fresh easterly winds south of 24N following the trough Sun through Tue. Fresh to strong winds will pulse off Hispaniola during the late afternoons and early evenings through Tue. $$ GR