000 AXNT20 KNHC 131138 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Fri Aug 13 2021 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 1030 UTC. ...SPECIAL FEATURES... Tropical Depression Fred is centered near the coast of eastern Cuba at 22.0N 76.7W at 13/0900 UTC or about 520 nm east-southeast of Key West, Florida. It is moving WNW at 9 kt with estimated minimum central pressure at 1013 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Wave heights with Fred are in the 8-10 ft range. Satellite imagery shows that the center of Fred is exposed once again as it is out running its deep convection of the scattered to moderate type intensity that is occurring from 18N to 21N between 74W-77W including portions of eastern Cuba. Similar convection is within 30 nm of a line from 16N77W to 18N76W. Scattered moderate convection is north of eastern Cuba to 25N between 72W-77W including the southeastern and central Bahama Islands. Fred is forecast to turn toward the northwest or Sat. On this forecast track, Fred is expected to move along or just north of eastern and central Cuba through tonight, be near the Florida Keys on Sat, and near the west coast of Florida on Sun. From today into Mon, 3 to 7 inches of rain are anticipated across the Keys, southern and central Florida north towards the Big Bend, with isolated maximum totals of 10 inches. 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 Fred NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A small area of low pressure with a pressure of 1010 mb is near 15N47W or about 870 nm east of the Lesser Antilles. It is producing clusters of scattered moderate convection within 240 nm to its west. An overnight ASCAT data pass suggested that the low pressure is elongated in an east to west fashion, with the strong winds of 20-25 kt present over its eastern section. Despite this, environmental conditions are expected to gradually become more conducive for additional development and a tropical depression is likely to form within the next couple of days. This system is forecast to move generally westward at about 20 mph across the tropical Atlantic, reaching portions of the Leeward Islands Sat night, and Virgin Islands on Sun. Interests in these locations should monitor the progress of this disturbance. This system has a high chance of tropical cyclone formation during the next 48 hours. Please read the latest NHC Tropical Weather Outlook at hurricanes.gov for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 20W from 03N to 21N, moving westward around 10 kt. The wave marks the leading edge of deep atmospheric moisture. Scattered moderate to isolated strong convection is seen east of the wave to the coast of Africa and from 06N to 10N. A central Atlantic tropical wave is west of the Special Features low pressure along 49W from 03N to 20N. It is moving westward near 15 kt. Scattered moderate convection is within 120 nm either side of the axis from 03N to 09N. Another tropical wave is along 59W/60W south of 23N to South America. It is moving westward also near 15 kt. Scattered moderate convection is within 120 nm west of the wave from 19N to 22N. This wave will move across the Lesser Antilles and into the eastern Caribbean Sea today. A Caribbean tropical wave has its axis along 80W south of 16N to across central Panama into the E Pacific Ocean. It is moving westward at 10 to 15 kt. Scattered showers and thunderstorms are noted within 120 nm east of the wave from 14N to 16N. ...MONSOON TROUGH/ITCZ... THe monsoon trough extends across the coast of Africa near the Senegal-Gambia border at 14N16W to 08N21W and to 06N31W. The ITCZ then continues from 06N31W to near 07N40W. Aside from convection mentioned above with the tropical wave along 20W, scattered moderate convection is seen within 180 nm north of the ITCZ between 32W-36W. ...GULF OF MEXICO... An upper-level trough is over the eastern Gulf. It is helping to trigger scattered showers and isolated thunderstorms over the central and southern across the eastern Gulf and over South Florida. Locally fresh winds and seas up to 4 ft are expected near heavier showers and stronger thunderstorms. Otherwise a ridge of high pressure over the N Gulf near 29N87W is promoting gentle to moderate ENE to ESE winds and seas of 2 to 3 ft across most of the Gulf. For the forecast, Tropical Depression Fred along the north coast of Cuba near 22.0N 76.7W 1013 mb at 5 AM EDT moving WNW at 9 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will strengthen to a tropical storm near 22.6N 78.4W this afternoon with maximum sustained winds 35 kt gusts 45 kt, reach near 23.6N 80.2W late tonight, near 24.8N 81.5W Sat afternoon with maximum sustained winds 40 kt gusts 50 kt, to near 26.4N 82.5W late Sat night, to near 28.1N 83.7W early Sun afternoon with maximum sustained winds 45 kt guts 55 kt, to near 29.6N 84.6W late Sun night and weaken to a tropical depression as it moves inland to near 32.5N 85.8W by late Mon night. Expect hazardous marine conditions over most of the eastern Gulf Sat through Mon. Otherwise, gentle to moderate winds and slight seas will persist through the period. ...CARIBBEAN SEA... Refer to the Special Features section for information on Tropical Depression Fred, and the Tropical Waves section for convection in the basin. Gentle to moderate trades and seas at 3 to 5 ft are seen across the central and E basin. Gentle trades and seas of 1 to 3 ft prevails for the rest of the basin. For the forecast, Tropical Depression Fred near the north coast of Cuba will strengthen to a tropical storm today and move into the Gulf of Mexico Sat. Fresh to locally strong winds will persist across most the eastern and central Caribbean through Fri, becoming light to gentle during the weekend. Light to gentle winds and slight seas will persist elsewhere. Low pressure located well east of the Lesser Antilles is expected to reach portions of the Leeward Islands Sat night, and the Virgin Islands Sun as a possible tropical cyclone. Expect strong gusty winds along with scattered to numerous showers and thunderstorms with this system. ...ATLANTIC OCEAN... Refer to the Special Features section for details on Tropical Depression Fred and an area of low pressure in the central Atlantic near 14N45W. Two upper-level lows, one is S of Bermuda near 28N63W and another one is over northern Florida near 29N83W. They are triggering scattered showers and isolated thunderstorms from 25N to 29N between 58W and 65W, and over S Florida and the NW Bahamas. For additional convection across the Atlantic Basin, refer to the Monsoon Trough/ITCZ section above. A ridge of high pressure stretching west-southwestward from the N central Atlantic across Bermuda to N Florida. Light to gentle winds and seas at 2 to 4 ft dominate N of 25N between 24W and 69W. Moderate to fresh trades and seas of 4 to 6 ft are evident from 10N and 25N between the African coast and the Lesser Antilles, and also N of 19N between 69W and the Florida-Georgia coast. Mainly gentle to moderate winds and seas of 4 to 6 ft seas prevail for the rest of the basin. For the forecast west of 65W, Tropical Depression Fred near 22.0N 76.7W 1013 mb at 5 AM EDT is moving WNW at 9 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will strengthen to a tropical storm near 22.6N 78.4W this afternoon with maximum sustained winds 35 kt gust 45 kt, reach near 23.6N 80.2W late tonight and across the rest of the Straits of Florida and to the eastern Gulf of Mexico Sat. Numerous squalls and thunderstorms associated over the far southwest part will gradually shift westward through Sat. The northern part of a tropical wave will move across the far southern waters today through late Sun. Low pressure located well east of the Lesser Antilles is pressure is expected to reach portions of the Leeward Islands Sat night and the Virgin Islands Sun as a possible tropical cyclone. Expect strong gusty winds along with scattered to numerous showers and thunderstorms with this system. $$ Aguirre