090 AXNT20 KNHC 190439 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1239 AM EDT Sun Aug 19 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 07N-18N along 25W, moving W at 10 kt. The wave is in a strong deep layer environment and is being affected by dry and dust air intrusion in the lower levels as depicted in GOES-16 water vapor and enhanced IR imagery. Scattered moderate convection is from 05N-09N between 16W-25W. A tropical wave is in the central Atlc with axis extending from 06N-18N along 42W, moving W at 15 kt. The wave is entering a low deep layer wind shear environment, however, it is being severely affected by Saharan dry air and dust that is hindering convection at this time. A tropical wave is in the E Caribbean with axis extending from 08N-18N along 66W, moving W at 15 kt. Both CIRA LPW and GOES-16 water vapor imagery show the northern wave environment being affected by low level dry air, which is limiting precipitation over the Leeward Islands. Scattered showers are, however, over portions of the Windward Islands. A tropical wave is in the western Caribbean with axis extending from 08N-20N along 82W, moving W at 15 kt. The wave is in a moderate to strong deep layer wind shear environment and in a mostly a dry enviromnent. Shallow moisture in the northern wave environment and diffluent wind aloft support scattered showers and tstms from 17N-21N between 76W-81W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of W Africa near 14N16W to 07N23W to 09N41W. The ITCZ begins near 09N43W and continues to 09N61W. Besides the convection mentioned in the tropical waves section, scattered showers are within 120 nm of the ITCZ. ...DISCUSSION... GULF OF MEXICO... A 1020 mb high is centered over the W Atlantic near 30N68W. A ridge axis extends W from the high to E Texas producing 10 kt SE return flow over the Gulf of Mexico. Widely scattered moderate convection is over the N Gulf N of 29N between 83W-90W. A surface trough is over the Yucatan Peninsula from 20N90W to 17N92W. Scattered moderate convection is over the Yucatan Peninsula, S Mexico , and the E Bay of Campeche. An upper level low is centered over W Cuba near 23N83W producing nocturnal thunderstorms over S Florida, and W Cuba. Expect surface ridging to prevail across the basin through Wed. Also expect showers over the N Gulf to continue through Sun. CARIBBEAN SEA... Two tropical waves are over the Caribbean Sea. See above. Scattered moderate convection is noted over Hispaniola, N Venezuela, N Colombia, Panama, Costa Rica, E Nicaragua, and E Honduras. Otherwise, surface ridging extending from the Atlantic to the northern half of the basin, continues to support fresh to strong winds in the south-central Caribbean. In addition, expect showers and convection to persist over the SW Caribbean for the next several days. ATLANTIC OCEAN... Two tropical waves are over the tropical Atlantic. See above. A 1020 mb high is centered over the W Atlantic near 30N68W. Widely scattered moderate convection is over the N Bahamas. A surface trough is over the central Atlantic from 32N50W to 26N60W. Scattered showers are within 90 nm of the trough. A 1026 mb high is over the Azores near 39N26W producing ridging and fair weather over the E Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa