000 AXNT20 KNHC 271757 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 PM EDT TUE SEP 27 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... Tropical wave along 52W/53W from 6N-18N with a 1008 mb low along the wave near 11N53W moving west-northwest near 15 kt over the past 24 hours. Wave shows that it is well organized and a tropical depression or tropical storm could form later today or tonight. Scattered moderate to isolated strong convection is within 60/75 nm of a line from 12N50W to 15N52W. Scattered showers and isolated thunderstorms dot the area from 10N-17N between 49W-57W. Regardless of tropical development, heavy rains and strong gusty winds, possibly to tropical storm force, are expected to spread over portions of the Lesser Antilles beginning tonight and continuing into Wednesday. Please see the Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details. ...TROPICAL WAVES... Tropical wave in the east Tropical Atlantic extends along 23W- 24W from 3N-14N moving west near 25 kt over the past 24 hours. Wave coincides with a 700 mb global model low and trough and remains embedded within an area of moisture as seen on the Total Perceptible Water imagery. No associated deep convection is noted. Tropical wave in the Caribbean extends along 71W/72W from 10N- 19N moving west at 10 to 15 kt over the past 24 hours. Wave is trailing a weak 700 mb global model trough and remains embedded within an area of moisture as seen on the Total Perceptible Water imagery. Wave is beneath an upper trough partially masking the satellite signature. No associated deep convection is noted. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 14N17W then along 7N23W 8N34W to 10N42W. The ITCZ is again disrupted by the tropical wave in the special features above. Clusters of scattered moderate to isolated strong convection are from 5N-8N between 11W-15W, 3N-7N between 19W- 22W, within 150/180 nm north of the monsoon trough between 24W- 41W, and within 210/240 nm south of the monsoon trough 28W-42W. ...DISCUSSION... GULF OF MEXICO... An upper trough over the east CONUS is supporting a stationary front along the coast of southwest Louisiana and Texas. A surface trough is just offshore extending from 29N94W along 24N96W 21N96W into the Bay of Campeche to the coast of Mexico near 18N94W. Scattered to numerous showers and isolated thunderstorms are south of 28N west of 92W. This front and trough are beneath an upper ridge that is anchored over central Mexico and covers the Gulf west of 84W. An upper trough covers the Florida peninsula extending from the west Atlantic across Florida near Cape Canaveral to the Florida Keys generating scattered to numerous showers and scattered thunderstorms from 23N-26N east of 83W through the Straits of Florida and over the Florida Keys. The west Gulf surface trough will drift west and weaken through Wednesday night. A cold front will enter the north Gulf Thursday, becoming stationary from central Florida to the southwest Gulf Friday. CARIBBEAN SEA... The upper ridge over the Gulf of Mexico covers the far west Caribbean west of 80W. Isolated showers and thunderstorms dot the northwest Caribbean north of 20N between 80W-85W. An upper low north of the Hispaniola extends an upper trough through the Mona Passage along 15N70W to east Panama generating scattered showers and isolated thunderstorms north of 15N to over the Leeward/Virgin Islands between 61W-67W. The monsoon trough extends along 10N from over Colombia to across Costa Rica generating scattered showers and isolated thunderstorms south of 13N west of 77W. The tropical wave will continue west and move through the west Caribbean through Friday. The 1008 mb low along the tropical wave in the special features, is expected to become a tropical cyclone before it moves across the Windward Islands with Gale force winds north of the low as it crosses the Lesser Antilles. ...HISPANIOLA... Currently skies are mostly clear across the island this afternoon. The upper trough through the Mona Passage will shift west of the island by late Wednesday. Afternoon/evening showers and thunderstorms will continue through Wednesday. Thursday will bring an increase of moisture to the Dominican Republic when the tropical wave in the special features moves into the eastern Caribbean. This will increase the showers and thunderstorms especially across the south portion of the island through the end of the week. ATLANTIC OCEAN... The upper low is centered in the west Atlantic near 30N80W with an upper trough extending across Florida to over the Florida Keys and supporting a surface trough that extends from a 1012 mb low near 31N80W along 28N79W to over Florida near Fort Lauderdale. A second upper low is centered north of Hispaniola near 23N69W. Between these upper lows is wedged an upper ridge providing diffluence aloft to generate scattered showers and isolated thunderstorms from 22N-28N west of 71W and north of 28N between 70W-76W. A surface ridge covers the northwest and north/central Atlantic anchored by a 1024 mb high 36N60W. An upper trough extends over the north/central Atlantic to 30N supporting a cold front that extends through 32N43W to 30N50W becoming stationary to 50N58W where it dissipates to 29N58W. Scattered showers and possible isolated thunderstorms are within 120 nm of the front east of 56W. The remainder of the Atlantic east of the above front is dominated by a surface ridge anchored by a 1033 mb high east of the Azores. Winds and Seas will increase over the west Tropical Atlantic Wednesday then north of the Puerto Rico and Hispaniola on Friday as the low/tropical wave in the special features moves into the Caribbean. For additional information please visit http://www.hurricanes.gov/marine $$ PAW