000 AXNT20 KNHC 310603 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT Fri Jul 31 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...SPECIAL FEATURES... ISAIAS has become a hurricane. The center of Hurricane ISAIAS, at 31/0600 UTC, is near 20.6N 72.7W. This position also is about 39 nm/70 km to the SE of Great Inagua Island in the Bahamas. ISAIAS is moving NW, or 305 degrees, 16 knots. The estimated minimum central pressure is 992 mb. The maximum sustained wind speeds are 70 knots with gusts to 85 knots. Precipitation: scattered to numerous strong is from 100 nm to 250 nm of the center in the SE semicircle, in much of the Dominican Republic and its coastal waters to the NE of the Hispaniola; similar precipitation also is between the northern coast of Haiti and the SE Bahamas near 22N between 71W and 74W. A squall line is racing toward the WNW about 30 knots, near 24N76W in the Bahamas. This is the leading edge of the tropical storm-force winds that are around the periphery of ISAIAS. The center of ISAIAS will move near or on top of the Southeastern Bahamas overnight. ISAIAS is forecast to be near the Central Bahamas on Friday night, and move near or on top of the Northwestern Bahamas, and near South Florida on Saturday. Little change in strength is forecast during the next 48 hours. Hurricane-force winds extend outward up to 26 nm/45 km from the center, and tropical storm-force winds extend outward up to 210 nm/390 km from the center. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml, and the Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml, for more details. An Atlantic Ocean tropical wave is along 20W/22W, from 21N southward, moving westward 10 knots. A 1009 mb low pressure center is along the tropical wave, near 13.5N. Precipitation: widely scattered moderate to isolated strong is within 540 nm of the center in the SW quadrant. The low pressure center has a small window of opportunity in order to become a tropical depression through Friday, while it moves northward 10 mph, before the environmental conditions become less conducive for development. The chance of formation into a tropical cyclone, during the next 48 hours, is medium. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 42W/43W, from 22N southward, moving W 20 knots. Precipitation: any nearby precipitation is in the monsoon trough. A Caribbean Sea tropical wave is along 85W/86W, from 20N southward, moving W 20 knots. The wave is passing through parts of Honduras, Nicaragua, and the westernmost sections of Costa Rica. Precipitation: isolated moderate to locally strong is within 60 nm of the coast of Honduras, along the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal near 16N17W, to 14N20W to 13N30W, 10N40W, and 08N50W. Precipitation: widely scattered moderate to isolated strong is within 360 nm to south of the monsoon trough between 30W and 51W. Isolated moderate is elsewhere from 20N southward from 60W eastward, including within 430 nm to the west of the 42W/43W tropical wave from 09N to 17N. GULF OF MEXICO... Upper level cyclonic wind flow covers the SW corner of the Gulf of Mexico, associated with an upper level inverted trough. Precipitation: scattered moderate to strong in a few clusters, is from 21N southward between the western sections of the Yucatan Peninsula and the coast of Mexico that is along 97W/98W. A surface ridge passes through central Florida, to a 1018 mb high pressure center that is near 27N88W, to the coast of Mexico along 25N. Broad surface anticyclonic wind flow spans the entire area. Tropical Storm Isaias is centered near 20.5N 71.9W 999 mb at 11 PM EDT moving NW at 16 kt. Maximum sustained winds 50 kt gusts 60 kt. Weak high pressure in the NE Gulf of Mexico will drift westward during the weekend. Isaias is forecast to move NW to the Central Bahamas on Friday evening and night, and then veer more NNW toward the NW Bahamas, and near SE Florida on Saturday. Isaias is expected to move N, then NE, across the W Atlantic Ocean, and remain to the east of the Gulf of Mexico through the weekend. CARIBBEAN SEA... A Caribbean Sea tropical wave is along 85W/86W, from 20N southward, moving W 20 knots. The wave is passing through parts of Honduras, Nicaragua, and the westernmost sections of Costa Rica. Precipitation: isolated moderate to locally strong is within 60 nm of the coast of Honduras, along the tropical wave. The monsoon trough is along 08N/10N, from Colombia along 74W westward, to the coastal waters of Central America from Nicaragua southward. Precipitation: isolated moderate is from 13N southward from 75W westward, in the SW corner of the Caribbean Sea. Tropical Storm Isaias near 20.5N 71.9W 999 mb at 0300 UTC moving NW at 16 kt. Maximum sustained winds 50 kt gusts 60 kt. Isaias will continue NW and reach the central Bahamas near 23.5N 76.1W Fri evening; then continue NNW through the NW Bahamas and near SE Florida and reach hurricane strength near 26.7N 79.0W on Sat evening, before moving N and away from the region through Monday. Tropical storm conditions and large seas will prevail tonight in the Windward Passage. Fresh to strong wind flow will persist to the south of Hispaniola into Friday. ATLANTIC OCEAN... A surface ridge extends from a 1022 mb high pressure center that is near 32N58W, toward central Florida. Broken to overcast multilayered clouds and other precipitation covers the Atlantic Ocean from 20N to 28N between 63W and 80W, away from Hurricane ISAIAS. Tropical Storm Isaias near 20.5N 71.9W 999 mb at 0300 UTC moving NW at 16 kt. Maximum sustained winds 50 kt gusts 60 kt. Isaias will continue NW and reach the central Bahamas near 23.5N 76.1W Fri evening; then continue NNW through the NW Bahamas and near SE Florida and reach hurricane strength near 26.7N 79.0W Sat evening; then turn more N and reach 30.0N 79.5W Sun evening, before exiting to the NNE Mon and Tue. Very large seas in SE swell are expected in a large section of the SW North Atlantic Ocean, to the west of 70W, and through the Bahamas waters from tonight through Friday, as the center of Isaias moves across the SE Bahamas late tonight. $$ mt