000 AXNT20 KNHC 302357 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 757 PM EDT TUE AUG 30 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. ...SPECIAL FEATURES... Hurricane Gaston is centered near 32.6N 51.9W at 30/2100 UTC or about 650 nm E of Bermuda and about 1255 nm W of the Azores moving ENE at 9 kt. Estimated minimum central pressure is 964 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Scattered to numerous moderate convection is from 30N-36N between 48W-54W. See latest NHC Forecast/Advisory under the AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. Tropical Depression Eight is centered near 34.4N 74.6W at 31/0000 UTC or about 70 nm SE of Cape Hatteras North Carolina moving NE 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 from 34N-36N between 73W-76W. 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 24.2N 87.7W at 31/0000 UTC or about 325 nm W of Key West Florida and about 300 nm WNW of Havana Cuba moving WNW at 4 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate and isolated strong convection is from 19N-26N between 79W-90W. Scattered moderate is elsewhere from 26N-29N between 78W-85W. 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... Tropical wave extends from 10N24W to 20N22W moving W at 15-20 kt. A 1009 mb low is centered along the wave axis near 16N where global models indicate a maximum 850 mb relative vorticity. In addition...the low and vorticity coincide with a 700 mb low and associated troughing that has emerged off the coast of West Africa. Isolated moderate convection is from 07N-17N between 16W-22W. Tropical wave extends from 08N34W to 18N37W moving W at 15-20 kt. The wave coincides with subtle 700 mb troughing between 35W-40W and a narrow and weak ribbon of 850 mb relative vorticity extending within the vicinity of the axis of the wave. No significant deep convection is occurring with the wave at this time. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from 10N25W to 08N31W to 10N42W to 09N44W. The Intertropical Convergence Zone axis extends from 09N44W to 08N54W. Scattered moderate and isolated strong convection is from 19N-22N between 15W-18W...and from 10N-12N between 42W-46W. Isolated moderate convection is from 04N-08N between 23W-44W...and from 08N-11N between 49W-62W. ...DISCUSSION... GULF OF MEXICO... The primary concern is Tropical Depression Nine centered in the SE and south-central Gulf waters this evening. The depression finds itself beneath an upper level anticyclonic circulation centered over the SE Gulf waters near 22N85W which will allow for gradual strengthening during the couple days. Farther W-NW as the overall synoptic pattern of weaker surface pressures continue across the basin...a surface trough extends from across southern Texas near Brownsville to 25N95W in the NW Gulf waters. Scattered showers and tstms are occurring across the NW Gulf waters N of 23N between 92W-99W. This convection is likely enhanced due to middle to upper level diffluence associated with an upper level anticyclonic circulation centered near 28N95W. Otherwise...by early Thursday...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 Tropical Depression Nine centered in the SE Gulf of Mexico waters SE to the central Caribbean near 15N73W. The ridging is providing an overall diffluent environment aloft in support of scattered showers and tstms occurring generally N of 19N between 76W-90W...including portions of Cuba and the Yucatan peninsula this evening. Farther south...weaker surface pressures are observed across much of Central America and given an overall diffluent flow regime over the region...isolated showers and tstms are occurring across inland portions of Central America and the SW Caribbean waters S of 15N W of 79W. Across the eastern Caribbean...isolated showers are noted on satellite imagery in the vicinity of 16N69W however much of eastern waters are under mostly fair skies this evening. Otherwise...moderate to fresh trades prevail E of 68W and are slightly stronger...fresh to strong...across the south-central Caribbean between 68W-78W. ...HISPANIOLA... Skies remain mostly fair this evening as northerly flow aloft is noted over the island on the southwestern periphery of an upper level low centered near 22N70W. Fair weather is expected to persist through Wednesday as the upper level low weakens and moves northward by the weekend. ATLANTIC OCEAN... Aside from active tropical cyclones...scattered showers and tstms are noted across the SW North Atlc waters on the NE periphery of Tropical Depression Nine centered in the SE Gulf of Mexico. The convection is generally S of 32N W of 75W...including the Bahamas and Florida peninsula. To the east...an upper level low is centered near 22N69W and supports isolated showers and tstms from 22N-28N between 66W-72W. Otherwise...the remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by a 1019 mb high centered near 25N59W and a stronger high at 1025 mb centered near 36N22W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN