000 AXNT20 KNHC 120544 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 25W/26W, from 16N southward, moving westward from 5 knots to 10 knots. Precipitation: isolated moderate to locally strong is within 300 nm to the southeast of the monsoon trough between 20W and 31W. An Atlantic Ocean tropical wave is along 50W, from 17N southward, moving westward about 10 knots. Precipitation: widely scattered moderate to isolated strong is from 06N to 10N between 47W and 53W. A Caribbean Sea tropical wave is along 78W, from 20N southward, moving westward from 15 knots to 20 knots. The tropical wave is moving through the westernmost sections of Jamaica. The monsoon trough is along 10N from 74W in Colombia beyond Costa Rica. Precipitation: numerous strong is within 90 nm to 180 nm to the south of the monsoon trough between 76W and 82W, and within 180 nm to the south of the monsoon trough between 83W and 86W. Isolated moderate to locally strong is within 520 nm to the west of the tropical wave from 14N northward. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal areas of SW Senegal, to 12N20W, 09N30W, 08N39W, and 08N42W. The ITCZ continues from 08N42W, to 06N53W at the coast of French Guiana. Precipitation: scattered moderate to strong from 10N to 15N between the coast of Africa and 20W. Isolated moderate to locally strong is elsewhere from 14N southward from 60W eastward. ...GULF OF MEXICO... A surface ridge passes through the NW Bahamas and Lake Okeechobee in south Florida, toward the upper Texas Gulf coast and SW Louisiana. Upper level cyclonic wind flow covers the Gulf of Mexico from the east central sections into the SW corner. Precipitation: widely scattered moderate to isolated strong is in the Isthmus of Tehuantepec of southern Mexico. Mostly moderate anticyclonic wind flow covers the western half of the Gulf of Mexico. Some fresh SE winds are from 26N southward from 90W westward. Gentle or slower winds are elsewhere. The sea heights are reaching 4 feet off the coast of NE Mexico; 3 feet from the coastal waters of the middle Texas Gulf coast into the west central Gulf; 1 foot in the NE corner of the area; and 2 feet elsewhere. 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... Please, read the SPECIAL FEATURES section, for details about the 78W tropical wave and the nearby precipitation. Upper level cyclonic wind flow covers the area that is from 10N northward between 60W and 70W. Precipitation: isolated moderate is in the area of the upper level cyclonic wind flow. The sea heights range from 6 feet to 9 feet from Hispaniola and Jamaica southward between the Mona Passage and 78W. The comparatively highest sea height of 9 feet is along 74W in the coastal waters/offshore waters of Colombia. The sea heights: range from 3 feet to 4 feet in the Venezuela coastal waters/offshore waters; 5 feet in the coastal waters/offshore waters of Puerto Rico; range from 3 feet to 4 feet from Jamaica southward between 78W and 80W; 2 feet elsewhere in the western Caribbean Sea waters. The exception is for 1 foot in the eastern coastal waters/offshore waters of Honduras. Strong easterly winds are from 18N southward between 72W and 78W. Moderate and fresh NE winds are in the eastern one-third of the area. Moderate or slower winds have been in the western one-third of the area. 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. ...ATLANTIC OCEAN... The GFS model for 500 mb and for 700 mb shows that an inverted trough and cyclonic wind flow cover the area that is from Cuba northward between 70W and 80W. Precipitation: scattered moderate to widely scattered strong is from Cuba to 28N between 70W and 80W, and on the Caribbean Sea side of Cuba for 300 nm to the south of Cuba. A Caribbean Sea tropical wave is moving through the westernmost sections of Jamaica. A surface trough passes through 31N42W, to 23N57W. Precipitation: widely scattered moderate to isolated strong is from 19N northward between 50W and 62W. Upper level cyclonic wind flow covers the area that is from 20N northward between 50W and 62W. A surface ridge extends from a 1023 mb high pressure center that is near 30N59W, through 28N66W, across the NW Bahamas and Lake Okeechobee in south Florida, toward the upper Texas Gulf coast and SW Louisiana. Strong NE winds are within 240 nm on either side of 24N33W 31N13W. Fresh NE winds are within 240 nm to 360 nm on either side of the rest of the line 32N13W 27N27W 19N38W 14N49W 16N60W. Mostly fresh to moderate southerly winds are from the monsoon trough/ITCZ southward. Moderate or slower winds are in the remainder of the Atlantic Ocean. The sea heights range from 7 feet to 11 feet from 30W eastward. The comparatively highest sea heights range from 9 feet to 11 feet from 18N northward. The sea heights range from 3 feet to 6 feet in the remainder of the Atlantic Ocean. A new outbreak of Saharan dust was in the eastern Atlantic Ocean on Friday. The Saharan Air Layer tracking product from CIMSS was indicating that African dust was reaching the eastern Caribbean Sea. 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 to Tue. Fresh to strong winds will pulse off Hispaniola during the late afternoons and early evenings through Tue. $$ mt/al