000 AXNT20 KNHC 222317 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Oct 23 2021 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... The axis of a tropical wave is along 45W, south of 17N and it is moving W at 10-15 kt. Scattered moderate convection is observed from 05N to 10N and between 45W and 50W. The axis of a tropical wave is along 60W/61W, south of 17N and it is moving W at 10-15 kt. Scattered showers are noted near Trinidad and Tobago, and over parts of eastern Venezuela and Guyana. The axis of a tropical wave is along 72W, south of 21N, extending from Hispaniola to W Venezuela, and it is moving W at 10-15 kt. The wave is enhancing some shower activity over Hispaniola and W Venezuela, including Lake Maracaibo. The axis of a tropical wave is along 80W, south of 21N, extending from the central Cuba to Panama, and it is moving W at 10-15 kt. Convection has flare-up over much of Cuba due to the tropical wave combined with a diffluent pattern aloft. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of The Gambia near 13N17W to 07N24W. The ITCZ continues from 07N24W to 05N40W to 04N51W. Scattered moderate convection is noted within 60 nm of the ITCZ between 25W and 33W. GULF OF MEXICO... Scattered showers and thunderstorms are observed across the southern portion of the Gulf of Mexico, southern Florida and the Florida Keys. Abundant low level moisture combined with a diffluent pattern aloft supports this convective activity. The rest of the Gulf, especially N of 25N, is under a drier airmass that is suppressing the development of showers and thunderstorms. A frontal boundary drapes across the northern Gulf states. A weak ridge dominates the basin producing mainly gentle to moderate winds. Seas S of 25N are 3-4 ft, with the highest seas occurring in the Florida Straits, and 1-3 ft elsewhere. For the forecast, the frontal boundary draped across the northern Gulf of Mexico will press southward across the eastern Gulf through Sat. The front is expected to stall later on Sat and will linger across the southern Gulf before dissipating by Sun night. Moderate to fresh winds are expected across the NW Gulf on Sat into Sun. Gentle to moderate winds will prevail elsewhere through early next week. CARIBBEAN SEA... Three tropical waves are moving westward across the Caribbean. Please, the Tropical Waves section for details. The most recent scatterometer data provided observations of moderate to locally fresh trades across the east and central Caribbean, with mainly gentle to moderate winds over the NW Caribbean. Seas are generally 3-6 ft S of 18N E of 80W, and 1-3 ft elsewhere. Moderate to fresh winds are E of the Lesser Antilles, with seas of 8 to 10 ft based on altimeter data. A diffluent pattern aloft continues to support the development of showers and thunderstorms over Cuba, Jamaica, northern Central America, and the Yucatan Peninsula. Shallow moisture embedded in the trade wind flow is noted elsewhere producing isolated to scattered passing showers. For the forecast, high pressure N of the area will support fresh to locally strong trades E of the Windward Islands through the weekend. Moderate to fresh winds are expected over the south- central Caribbean with winds reaching locally strong in the Venezuela basin through Sun. Winds are expected to become moderate to fresh across the central Caribbean from Mon through Wed with gentle to moderate tradewinds prevailing elsewhere. ATLANTIC OCEAN... A large area of showers and thunderstorms is present over the SW N Atlantic, including the Bahamas and SE Florida. A surface trough is analyzed from 30N70W to the SE Bahamas while another trough is over SE Florida. Upper diffluence is helping to induce this convective activity. The most recent scatterometer data show fresh winds in association with the convection. A frontal trough extends from 31N42W to 26N59W. Scattered showers are near the trough axis. The rest of the Atlantic forecast waters are under the influence of a ridge with a 1028 mb high pressure located N of area near 36N51W, and another 1026 mb high pressure situated S of the Azores near 35N27W. A stationary front is noted just N of the Canary Islands. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Continues ash emission is noted with small column height. Medium to high volcanic ash concentration in the vicinity of the volcano. Marine and aviation interests should monitor this ongoing situation by reading the Volcanic Ash Advisory issued by Meteo- France, at http://vaac.meteo.fr/volcanoes/la-palma/. For the forecast, a trough off the southeast Florida coast will support convection across the region through Sat. A cold front will move off the SE U.S. coast tonight. The front will push southward toward South Florida on Sat and stall through Sun. Moderate to locally fresh winds will develop north of the boundary on Sun off the Florida coast. Expect showers and thunderstorms along this boundary through the weekend. $$ GR