452 AXNT20 KNHC 211205 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 AM EDT Tue Aug 21 2018 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave has its axis extending from 05N36W to 13N36W to 19N54W, moving westward at 10-15 kt. Scattered moderate convection is noted from 08N to 10N between 25W and 32W. A tropical wave over the eastern Caribbean has its axis along 63W/64W south of 19N, moving westward at 15 to 20 kt. Scattered moderate convection trails the wave within 30 nm of a line from 11N59W to 11N62W. A western Caribbean tropical wave has its axis extending along 83W and south of 20N, moving westward at 10-15 kt. Only isolated showers and thunderstorms are noted within 60 nm east of the wave. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from coast of Senegal near 14N16W to 10N20W, then to 08N40W. The intertropical convergence zone continues westward to the mouth of the Orinoco River near 09N61W. No significant convection is noted. ...DISCUSSION... GULF OF MEXICO... Weak ridging reaches across the northern Gulf of Mexico along roughly 27N, maintaining light to gentle breezes and 1 to 3 ft seas. Gentle to moderate easterly flow is noted elsewhere south of the ridge. Latest NWS mosaic radar display shows isolated showers and thunderstorms across much of the eastern part of the gulf, mainly due to a weak trough over that area. Scattered to numerous showers and thunderstorms are active along the coast of Mexico in the far southwest Gulf, related to the normal evening/overnight trough that sets up off Yucatan and moves westward, but also largely enhanced by an upper low centered over the southwest Gulf. The Yucatan surface trough will persist each afternoon, then drift westward across the southwest gulf waters during the overnight hours accompanied by a fresh east to southeast wind shift with the trough dissipating along 96W during the late mornings. Otherwise, high pressure ridging will remain across the northern gulf waters, with the associated gradient producing gentle to moderate anticyclonic flow. CARIBBEAN SEA... The pressure gradient across the area will maintain fresh to strong winds over the south central Caribbean off the coast of Colombia and across the Gulf of Venezuela through Thu. Moderate to fresh trades will continue elsewhere through Thu. The tropical wave along 83W will move across the rest of the western Caribbean tonight. The tropical wave along 63W/64W will move across the central Caribbean late Tue through Wed night and enter the eastern part of the central Caribbean Thu. ATLANTIC OCEAN... Over the western Atlantic, a surface trough is analyzed from near 30N72W to 24N76W in the central Bahamas, supported in part by an upper trough over the same area. Another trough extends from 32N57W to 27N67W, and another one from near 32N42W to 24N51W. Scattered showers and isolated thunderstorms are north of 23N between 59W and 75W. The subtropical ridge is displaced slightly north to along 31N, north of the troughs. High pressure ridging will continue over the basin through the next several days. The trough extending across the central Bahamas will continue westward through this evening. Scattered showers and isolated thunderstorms along and near the trough will affect mainly the western and northwestern sections of the Bahamas through tonight. Farther east, 1027 mb ridging is centered near 34N41W, supporting generally moderate north to northeast winds north of 20N. Saharan dust and associated dry air noted mainly east of 50W is inhibiting convection from developing across the eastern and central Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre