000 AXNT20 KNHC 161052 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sat Sep 16 2023 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1050 UTC. ...SPECIAL FEATURES... Post-Tropical Cyclone Lee is centered near 41.8N 66.0W at 16/0900 UTC or 200 nm SSW of Halifax Nova Scotia, moving N at 22 kt. Estimated minimum central pressure is 965 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Scattered moderate convection in the form of rain bands is N of 39N between 55W and 75W. A northward motion but at a slower forward speed is expected later today, and the center of Lee is forecast to reach western Nova Scotia around midday. Lee is then expected to turn toward the north-northeast and northeast and move across Atlantic Canada tonight and Sunday. Lee is expected to be at or just below hurricane strength when it reaches Nova Scotia later today. Weakening is forecast tonight and Sunday while Lee moves across Atlantic Canada. Tropical Storm Margot is centered near 35.0N 38.3W at 16/0900 UTC or 570 nm WSW of the Azores, moving SW at 6 kt. Estimated minimum central pressure is 990 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Scattered moderate convection is from 32N to 35N between 37W and 42W. Margot is expected to continue to make a slow clockwise loop during the next day or two. A faster northeastward to eastward motion is forecast by early next week. Additional weakening is forecast during the next day or so, though Margot may re-intensify some by early next week. Tropical Depression Fifteen is centered near 17.9N 45.3W at 16/0900 UTC or 930 nm ENE of the Lesser Antilles, moving NNW at 12 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are 12 ft. Numerous moderate isolated strong convection is from 18N to 24N between 42W and 49W. A general northwest or north-northwest motion is expected to continue for the next few days. Strengthening is expected during the next few days, and the depression is forecast to become a tropical storm later today and it could become a hurricane by early next week. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC Forecast/Advisories and Public Advisories at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 31W, from 02N o 14N, moving westward 5 knots to 10 knots. Scattered moderate convection is from 07N to 14N between 30W and 35W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from 14N17W to 11N25W to 12N35W. For convection details, see the Tropical Waves section. ...GULF OF MEXICO... A weak pressure gradient prevails in the region, thus maintaining light to gentle variable winds around a center of high pressure of 1016 mb near 26N86W. Seas are slight basin-wide. Otherwise, middle to upper level diffluent flow support isolated showers along the northern gulf offshore waters. For the forecast, surface ridging across the northern Gulf will dominate the basin through early Sun, supporting mainly light to gentle variable winds along with slight seas. A weak cold front is forecast to move off New Orleans and Mississippi into the NE Gulf Sun morning followed by N to NW moderate winds and isolated to scattered showers. The front is forecast to move E of the area by Sun night. A weak surface ridge will develop afterward, supporting gentle to moderate NE to E winds through Tue. Otherwise, winds will pulse to moderate to fresh W-NW of the Yucatan Peninsula this evening and Sun evening. ...CARIBBEAN SEA... Scattered showers are ongoing in the Leeward Islands, between Jamaica and E Cuba, and in the Panama and Costa Rica offshore waters. Otherwise, moderate to fresh winds prevail in the central Caribbean along with moderate seas. Gentle to moderate E winds and slight seas are elsewhere. For the forecast, northerly swell affecting the NE Caribbean Passages will gradually subside today, then is forecast to build again Mon through Wed due to Tropical Depression Fifteen, which is forecast to remain well NE of the area. Otherwise, moderate to fresh trades will prevail across the Central Caribbean while gentle to moderate winds will dominate elsewhere through the forecast period. ...ATLANTIC OCEAN... Please, read the Special Features section, for details on Tropical Depression Fifteen. For the forecast W of 55W, Tropical Depression Fifteen will strengthen to a tropical storm near 19.6N 46.4W this afternoon, move to 21.5N 48.3W Sun morning, 23.1N 49.8W Sun afternoon, 24.5N 51.3W Mon morning, strengthen to a hurricane near 25.9N 53.0W Mon afternoon, and 27.2N 55.1W Tue morning. Fifteen will change little in intensity as it moves near 31.0N 58.4W early Wed. High pressure will prevail across the waters through the weekend. Otherwise, a weak cold front is forecast to move off the SE U.S. coast early next week with new high pres building down behind it. $$ Ramos