000 AXNT20 KNHC 292333 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 651 PM EDT Wed Jul 29 2020 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 2330 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Nine is centered near 16.4N 65.6W at 29/2100 UTC, or about 105 nm S of St. Croix, moving WNW at 20 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered strong convection extends out 300 nm from the center in the NE quadrant and 270 nm SW quadrant. Heavy rain may lead to life- threatening flash flooding over the Leeward Islands, Virgin Islands, Puerto Rico and the Dominican Republic today into Thu. ASCAT pass shows that tropical storm force winds of 35-40 kt exist in the NE quadrant in the area between 150-270 nm NE of the center. These winds are currently affecting the northern Leeward Islands, and will be spreading to the Virgin Islands. The highest seas this afternoon and evening are expected on the Atlantic Ocean side of the northern Leeward and Virgin Islands, with peak seas of 18 ft. PTC Nine is forecast to remain at tropical storm strength as it interacts with Hispaniola on Thursday, and Cuba and the Bahamas on Friday. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more details. ...TROPICAL WAVES... A tropical wave has been added to the analysis with axis along 20W from 03N-18N, moving W at 15 kt. Scattered moderate convection is from 05N to 16N east of 29W. A tropical wave is along 35W from 21N southward, moving W at 20 kt. Scattered moderate convection is seen from 03N-08N Between 32W-39W. A tropical wave is along 77W from 19N southward, moving W at 20 kt. Scattered moderate convection is near eastern Panama where the wave axis meets the east Pacific monsoon trough. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Mauritania near 18N16W to 10N30WW to 08N45W. The ITCZ continues from 08N45W to 09N53W. Scattered moderate convection is observed from 05N-13N between 23W-28W and from 02N-07N between 39W-48W. GULF OF MEXICO... A ridge extends across the northern Gulf supporting gentle to moderate E to SE winds and 2 to 4 ft seas across the basin, except for fresh winds and 3 to 5 ft seas off the west coast of the Yucatan peninsula. An upper-level low over NE Mexico is generating upper-level diffluence over the west-central Gulf, enhancing scattered moderate showers and tstorms over the w western Gulf, west of 95W. For the forecast, a ridge will dominate the Gulf waters through Fri, supporting mainly gentle to moderate return flow. Beyond that, much will depend on the track and intensity of Potential Tropical Cyclone Nine, currently located over the eastern Caribbean. This system may approach the Florida Straits and far southeast Gulf by Sat and Sun. CARIBBEAN SEA... Potential Tropical Cyclone Nine is currently affecting the eastern Caribbean, east of 60W and north of 13N. See Special Features section above for the current details on Nine. Several stations on Guadeloupe and Martinique reported 24-hour rainfall amounts ending at 29/1200 UTC between 3 and 4 inches. For the forecast, seas as high as 10-15 ft are forecast through tonight for portions of the NE Caribbean in the waters south of Puerto Rico. Tropical storm force winds are forecast to be in the Mona Passage tonight, near Hispaniola Thu, and in the Windward Passage late Thu and Thu night. The NW Caribbean should monitor the progress of Nine in case the track shifts farther south. Winds and seas will largely diminish over the eastern Caribbean Fri, except for an area of swell to at least 8 ft that will penetrate through the Mona Passage. Tropical storm conditions will continue across portions of the Leeward Islands, the U.S. and British Virgin Islands and Puerto Rico through tonight. These conditions are forecast to reach portions of the Dominican Republic and Haiti by late tonight or early Thursday. ATLANTIC OCEAN... A small upper-level trough off the SE coast of the U.S. is inducing upper-level divergence to the SE of the trough. This is enhancing scattered moderate convection east of Florida and north of the NW Bahamas, north of 26N between 77W-81W. A surface ridge extends across the Atlantic from a 1024 mb high near 31N59W. Convection related to PTC Nine is currently occurring south of 23N between 59W-67W. The ASCAT pass showed that winds over 25 kt associated with the circulation of PTC Nine were confined to areas south of 24N between 56W-66W at that time. Potential Tropical Cyclone Nine has max sustained winds of 40 kt gusts 50 kt. PTC Nine will move to 17.5N 68.1W Thu morning, inland to 19.2N 71.0W Thu afternoon, 20.9N 74.2W Fri morning, 22.3N 76.9W Fri afternoon, 23.6N 78.9W Sat morning, and inland to 25.5N 80.8W Sat afternoon. PTC Nine will move inland over 28.6N 82.1W Sun afternoon. Tropical storm conditions are expected to reach the southeastern Bahamas and Turks and Caicos Thursday afternoon. $$ Torres