466 AXNT20 KNHC 221643 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Fri Oct 22 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 1200 UTC surface analysis and satellite imagery through 1635 UTC. ...TROPICAL WAVES... The axis of a tropical wave is along 44W, south of 17N and it is moving W at 10-15 kt. Scattered moderate convection is observed from 05N to 10N and between 39W and 50W. The axis of a tropical wave is along 59W, south of 17N and it is moving W at 10-15 kt. A broad surface curvature is evident on visible satellite imagery. Scattered showers are noted from the coasts of NE Venezuela and Guyana to 12N and between 55W and 63W. The axis of a tropical wave is along 70W, south of 21N, extending from the Dominican Republic to W Venezuela, and it is moving W at 10-15 kt. No deep convection is associated with this wave. The axis of a tropical wave is along 78W, south of 21N, extending from the E Cuba to Panama, and it is moving W at 10-15 kt. Scattered moderate to isolated strong convection is found where the wave interacts with the E Pacific monsoon trough, mainly from the coast of Panama to 13N and between 75W to 83W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of The Gambia near 13N17W to 07N22W. The ITCZ continues from 07N22W to 07N33W and 07N44W. Another segment of the ITCZ continues from 07N46W to 04N51W. Scattered moderate convection is noted within 60 nm of the ITCZ from 32W to 39W. GULF OF MEXICO... Scattered moderate to isolated strong convection is observed across the southern portion of the Gulf of Mexico, extending from SW Florida to the W Bay of Campeche, mainly as a result of divergence aloft and a surface trough present along 94W, from 17N to 23N. The rest of the Gulf, especially N of 25N, is under a dry airmass that is suppressing the development of showers and thunderstorms. A cold front drapes across the N Gulf, from the Florida panhandle to SE Texas, but it is not producing any significant convection. A weak pressure gradient results in moderate or weaker winds across the basin. 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, a cold front entering the northern Gulf of Mexico will continue to press southward across the eastern Gulf through Sat. The front is expected to stall later on Sat and will linger through early next week. Moderate to fresh winds are expected across the NW Gulf on Sat into Sun. Gentle to moderate winds will prevail in the western through early next week. CARIBBEAN SEA... Divergence aloft and a surface trough along the coast of the Yucatan peninsula result in scattered moderate convection in the Gulf of Honduras. The rest of the Caribbean Sea enjoys fairly tranquil weather conditions due in part to the dry Saharan airmass moving through the region. The modest pressure gradient between the 1028 mb ridge over the NW Atlantic and lower pressures in South America allow for fresh to locally strong trades E of 76W according to the latest scatterometer satellite data and synoptic observations. The strongest winds are found near the Lesser Antilles. Moderate or weaker trades are prevalent in the remainder of the Caribbean. Seas of 5-8 ft are occurring E of 75W and 2-5 ft elsewhere. A recent altimeter wave data show seas of 8 ft in the SE Caribbean. For the forecast, high pressure N of the area will support fresh to locally strong trades E of the Windward Islands through the weekend. Winds are expected to become moderate across the central Caribbean early next week. Moderate to fresh winds are expected over the south-central Caribbean with winds reaching locally strong in the Venezuela basin through Sun. Gentle to moderate tradewinds will prevail elsewhere. ATLANTIC OCEAN... A large area of showers and isolated thunderstorms is present over the western tropical Atlantic. The combination of a surface trough between Florida and the NW Bahamas and divergence aloft results in scattered moderate convection from 22N to 27N and between 73W and the coast of Florida. The storm activity is also affecting a good portion of the Bahamas island chain. Farther east, two other surface troughs, extending from 30N70W to 24N73W, and 30N45W to 26N59W, are producing widely scattered showers and isolated thunderstorms from 22N to 30N and between 47W and 71W. Recent scatterometer satellite data show fresh winds in association with the convection. The rest of the tropical Atlantic enjoys fairly tranquil weather conditions. A weak surface trough along 41W, from 20N to 24N, is only producing a few shallow showers, but its signature was quite evident on scatterometer data. An expansive 1028 mb subtropical ridge dominates the North Atlantic and the pressure gradient between this feature and lower pressures in South America result in fresh to strong trades from 06N to 19N and between 35W and the Lesser Antilles as observed on recent satellite-derived wind data. Fresh NE winds are also occurring E of 30W and from 20N to 30N. Seas of 7-10 ft are found E of 60W, with the highest seas occurring E of the Lesser Antilles and well W of the Canary Islands. Seas of 4-7 ft prevail elsewhere in the basin. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. 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, high pressure will move east of the area tonight as a weak cold front moves off the SE U.S. coast. The front will stall near the northern Bahamas through early next week. Moderate to locally fresh winds will develop north of the boundary Sat night into Sun off the central Florida coast. Expect showers and thunderstorms along this boundary. $$ DELGADO