000 AXNT20 KNHC 202349 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT WED JUL 20 2016 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...TROPICAL WAVES... Tropical wave in the east Tropical Atlantic extends along 20W from 11N-21N moving west near 15 kt over the past 6 hours. Wave coincides with a well defied 700 mb trough as depicted in the global models and within a highly amplitude surge of moisture as seen on the SSMI Total Precipitable Water imagery. No associated deep convection. Tropical wave in the west Tropical Atlantic extends along 60W from 10N-18N moving west-northwest near 20 kt over the past 12 hours. Wave coincides with a weak 700 mb trough as depicted in the global models and within a surge of moisture as seen on the SSMI Total Precipitable Water imagery. No associated deep convection. Tropical wave in the Caribbean extends along 79W/80W from 13N- 22N moving west near 25 kt over the past 24 hours. Wave coincides with a well defined 700 mb trough as depicted in the global models and within a surge of moisture as seen on the SSMI Total Precipitable Water imagery. No associated deep convection. Tropical wave in the south Gulf of Mexico extends along 94W/95W from 21N across Mexico into the east Pacific region moving west 15 to 20 kt over the past 24 hours. Wave precedes a 700 mb trough as depicted in the global models and is embedded within a broad area of moisture as seen on the SSMI Total Precipitable Water imagery. Scattered showers and isolated thunderstorms are south of 22N between 94W-97W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends across Africa into the east Tropical Atlantic near 19N16W and continues south of the Cape Verde Islands along 10N30W to 7N42W where the ITCZ begins and continues to South America near 6N55W. Scattered moderate to isolated strong convection is within 60 nm of line from 9N24W to inland over Africa near 12N16W. Clusters of scattered moderate to isolated strong convection are from 6N-9N between 28W-37W. ...DISCUSSION... GULF OF MEXICO... A large upper ridge anchored over south Arkansas covers the north Gulf of Mexico north of 25N with a ridge axis extending southwest to West Palm Beach, Florida. A cutoff upper low is in the south Gulf near 22N94W covering the remainder of the Gulf south of 25N with an upper trough axis extending east to the Yucatan Channel. A diurnal surface trough is inland over the west coast of the Yucatan peninsula generating scattered showers and isolated thunderstorms within 60 nm along the coast south of 21N east of 92W. Diffluence aloft between the upper level features is generating scattered showers and isolated thunderstorms from 23N-26N between Florida and Mexico and from 26N-29N between 86W-92W. Isolated showers and thunderstorms are possible across the remainder of the Gulf this evening. A surface ridge covers the north Gulf anchored by a 1022 mb high over northeast Louisiana. The surface ridge will persist through the end of the week. CARIBBEAN SEA... An inverted upper trough extends from east Panama through the Windward Passage into the southwest Atlantic to near 24N70W. An upper ridge is anchored over the Virgin Islands covering the east Caribbean and providing difflunce aloft to generate scattered showers and isolated thunderstorms north of 12N to over the Lesser and Greater Antilles between 60W-69W. Afternoon/evening scattered showers and isolated thunderstorms have developed inland over Hispaniola, Jamaica, and Cuba again this evening. These showers are moving west-northwest into the Caribbean waters. The remainder of the Caribbean is under fair skies this evening. The tight pressure gradient between the west Atlantic surface ridge and the lower pressure over South America is producing fresh to strong trade winds across the south- central Caribbean that will continue through the end of the week. The tropical wave will move into the east Caribbean tonight and into the central Caribbean by Saturday. ...HISPANIOLA... Afternoon scattered showers and isolated thunderstorms are moving from the Dominican Republic to over Haiti covering most of the island this evening. Thursday will usher in additional moisture with the tropical wave and could give the island more showers and thunderstorms Thursday night into Friday. ATLANTIC OCEAN... The upper trough dips south over the the far west Atlantic to 25N between 75W-80W supporting a surface trough that extends from 31N73W to the north Bahama Islands near 26N78W. Scattered showers and isolated thunderstorms are north of 30N between 62W- 75W. The inverted upper trough extends from the Caribbean through the Windward Passage 24N70W. A cutoff upper ridge is anchored near 26N68W and is providing difflunce aloft to generate isolated showers and thunderstorms from 23N-26N between 75W-80W. Afternoon scattered showers and isolated thunderstorms are inland and within 60 nm along the north coast of Hispaniola between 67W in the Mona Passage to 71W. Otherwise, high pressure dominates the remainder of the Atlantic with a surface ridge extending from a 1028 mb high in the north-central Atlantic near 35N44W to 31N57W then continuing west to inland over the southeast CONUS. The west Atlantic surface trough will persist through Friday. The surface ridge over the west Atlantic will shift east ahead of a weak frontal boundary approaching from the north that will dissipate through Friday off the northeast Florida coast. For additional information please visit http://www.hurricanes.gov/marine $$ PAW