000 AXNT20 KNHC 311101 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 701 AM EDT WED AUG 31 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 0600 UTC surface analysis and satellite imagery through 1030 UTC. ...SPECIAL FEATURES... Hurricane Gaston is centered near 33.4N 50.2W at 31/0900 UTC or about 740 nm east of Bermuda and about 1160 nm west of the Azores moving northeast at 8 kt. Estimated minimum central pressure is 956 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Scattered to numerous moderate convection is from 32N-35N between 48W-53W. See latest NHC Forecast/Advisory under the AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. Tropical Depression Eight is centered near 34.8N 74.3W at 31/0900 UTC or about 65 nm east-southeast of Cape Hatteras North Carolina moving northeast at 4 kt. Estimated minimum central pressure is 1011 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate convection is sheared to the northeast of the center, from 34N-37N between 72W-74W. See latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT3/WTNT33 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. Tropical Depression Nine is centered near 24.5N 88.1W at 31/0900 UTC or about 350 nm south-southwest of Apalachicola Florida and about 370 nm southwest of Tampa Florida drifting north at 2 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Numerous strong convection is from 22N-25N between 86W-89W. Scattered moderate to strong convection also from 21.5N-24N between 83W-86W. See latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends across the Cabo Verde Islands from 10N26W to 1010 mb low pressure near 15N25W to 19N24W, moving west at 15-20 kt. The gradient between the low pressure and ridging to the north is enhancing northeast winds across the eastern Atlantic north of 15N and east of 30W. The embedded circulation is drawing rich deep layer moisture northward across the eastern Cabo Verde Islands, possibly bringing a few showers to the region. The system is also interning dry Saharan air and dust to the north and west of the islands, limiting convection. Another tropical wave extends from 10N40W to 19N40W moving west at 15-20 kt. The wave coincides with mid level troughing between 35W-40W that shows up well on satellite derived high density winds, on the leading edge of a well defined plume of deep layer moisture. No significant deep convection is occurring with the wave at this time. The tropical wave follows another mid level trough centered around 50W. Model depictions indicate the tropical wave will dampen out over the next 24 to 36 hours between the more developed wave to the east and the troughing near 50W, which is expected to move across the Leeward Islands through late Thursday. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 10N29W to 08N35N to 08N40W. The intertropical convergence zone axis extends from 08N40W to 11N47W to 10N553W. Convergence of southwest flow into the monsoon trough is supporting scattered moderate convection within 60 nm of a line from 06N30W to 10N20W. Convergent trade wind flow into the ITCZ is supporting scattered moderate convection with 120 nm either side of the axis between 45W and 55W. ...DISCUSSION... GULF OF MEXICO... Tropical Depression Nine continues to develop over the south central Gulf this morning. Current buoy data along with a recent scatterometer pass indicated a broad area of strong winds over much of the eastern Gulf around T.D. Nine, but with the strongest areas of showers and thunderstorms confined to the south central Gulf around the center of T.D Nine and over the warmer waters of the loop current. Scattered showers and thunderstorms persist over the northeast Gulf as well, assisted by convergence of persistent fresh to strong northeast to east winds. T.D. Nine is expected to approach the Big Bend region of Florida reaching the coast by Thursday night. It will cross portions of northern Florida and southern Georgia and into the SW North Atlc region by Friday. CARIBBEAN SEA... An upper level ridge axis extends from over T.D. Nine centered in the south central Gulf of Mexico southeastward to the central Caribbean. The ridging is providing an overall diffluent environment aloft in support of scattered showers and thunderstorms across much of the Caribbean north of 15N and west of 80W. Training showers and thunderstorms continue to impact portions of central and western Cuba where heavy rainfall has been reported for the past couple of days. Scattered moderate to strong convection is also impacting the northern portions of the Yucatan peninsula. The subtropical ridge is building over the western Atlantic, allowing trade wind flow to increase across the south central Caribbean. ...HISPANIOLA... An upper low remains in place north of Hispaniola near 23N69W. Subsident northerly flow on the west side of the upper low has been suppressing convection since late Monday, but scattered showers and thunderstorms will again appear over the higher terrain in the interior later this afternoon. ATLANTIC OCEAN... Aside from active tropical cyclones...scattered showers and thunderstorms are noted over the Bahamas on the periphery of T.D. Nine centered in the Gulf of Mexico, and elsewhere west of 70W due to an upper low center near 23N69W, and Elsewhere the remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by a 1027 mb high centered near 35N25W. For additional information please visit http://www.hurricanes.gov/marine $$ CHRISTENSEN