000 AXNT20 KNHC 301817 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 217 PM EDT Thu Jul 30 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 1200 UTC surface analysis and satellite imagery through 1800 UTC. ...SPECIAL FEATURES... AS of 30/1500 ITC, Tropical Storm Isaias is centered near 18.1N 68.9W, or about 50 nm SW of Punta Cana, Dominican Republic, moving NW at 20 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained winds is 50 kt with gusts to 60 kt. Scattered moderate to strong convection extends out 200 nm from the center in the NE Quadrant and 300 nm SW quadrant. Tropical storm force winds extend outward up to 310 nm to the north of the center. ASCAT pass shows winds of 35-40 kt in the NE quadrant in the area between 66W-71W. These winds are currently affecting Hispaniola, the Mona Passage and western PR. The highest seas are expected on the Atlantic Ocean side north of 20N-24N, with peak seas of 13 to 20 ft in NE to E swell. Heavy rain may lead to life-threatening flash flooding and mudslides, as well as river flooding over Puerto Rico and Hispaniola today into Fri. On the forecast track, the center of Isaias will move over Hispaniola today and move near the Southeastern Bahamas by tonight or early Friday. Isaias is forecast to be near the Central Bahamas Friday evening and approach the Northwest Bahamas or southern Florida Saturday. 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 located about 200 nm southeast of the Cabo Verde Islands is analyzed along 20W, south of 19N with a 1011 mb low pressure well depicted by the latest ASCAT. Scattered moderate to isolated strong convection is noted from 08N-14N between 19W-24W. Some development of this system is possible during the next day or two and a low chance of formation in the next 5 days. An Atlantic tropical wave is along 40W from 20N southward, moving W at 20 kt. Scattered showers are seen from 03N-08N between 36W-43W. A Caribbean Sea tropical wave is along 82W from 19N southward, moving W at 20 kt. Scattered showers are near western Panama and eastern Costa Rica where the wave axis meets the east Pacific monsoon trough. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Mauritania near 15N16W to 11N26W to 11N36W. Scattered moderate convection extends about 180 nm to the south of the monsoon trough. GULF OF MEXICO... A ridge extends across the Gulf supporting gentle to moderate E winds and 2 to 4 ft seas across the basin, except for moderate 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 showers and thunderstorms over the western Gulf. 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 Tropical Storm Isaias, currently located over the eastern Caribbean. This system may approach the Florida Straits and far southeast Gulf by Sat and Sun. CARIBBEAN SEA... ASCAT data shows moderate winds in the western and the southwestern Caribbean. Scattered moderate convection is noted along the coast of Belize and the Gulf of Honduras. North of 17N to the coast of Cuba, moderate to fresh winds are noted. Scattered moderate to strong convection north of 14N and east of 74W is associated to T.S. Isaias. See details about T.S. Isaias above. Scatterometer indicates fresh to strong southeast winds north of 13N and east of 68W. Moderate SE winds are noted along the Lesser Antilles with scattered showers near the area. Tropical Storm Isaias will move over Hispaniola to 19.7N 71.4W this evening, 21.4N 74.2W Fri morning, 23.0N 76.5W Fri evening, 24.6N 78.2W Sat morning, 26.2N 79.4W Sat evening, and 28.0N 79.9W Sun morning. Isaias will change little in intensity as it moves to near 31.5N 79.1W early Mon. Tropical storm conditions will continue for portions of the Dominican Republic and Haiti through tonight, including the Windward Passage. ATLANTIC OCEAN... An 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 from 31N to 29N and some isolated activity over the Florida Panhandle. A 1023 mb high centered near 31N59W extends across the Atlantic where ASCAT pass indicates broad area of light winds north of 27N. A surface trough is present near 28N50W to 17N51W. Scattered showers are in the vicinity of the trough. Convection related to T.S. Isaias is south of 22N between 64W-72W. Tropical Storm Isaias will change little in intensity as it moves over Hispaniola today and move near the Southeastern Bahamas tonight Isaias is forecast to be near the Central Bahamas Friday evening and approach the Northwest Bahamas or southern Florida Saturday. Tropical storm conditions and very large seas are expected over a large portion of the SW North Atlantic waters as the center of Isaias approaches the SE Bahamas. Isaias is forecast to be near the Central Bahamas Fri night and approach the NW Bahamas or southern Florida Fri night and Sat. $$ Torres