897 AXNT20 KNHC 121752 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Aug 12 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 1200 UTC surface analysis and satellite imagery through 1735 UTC. ...SPECIAL FEATURES... Tropical Depression Fred is positioned north of E Cuba near 21.0N 74.9W at 12/1800 UTC or 105 nm W of Great Inagua Island, moving WNW at 12 kt. Estimated minimum central pressure is 1013 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Seas are reaching as high as 7 ft off the north coast of Cuba and the eastern and central Bahamas. Numerous moderate to isolated strong thunderstorms are active over the eastern semicircle of Fred, affecting the central and eastern Bahamas and Hispaniola, extending to the northern Caribbean. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT1.shtml for more details. A strong tropical wave over the central Atlantic is producing disorganized showers and thunderstorms, mainly to the west of the center. A recent scatterometer satellite pass depict a small area of low pressure along the northern part of the wave and strong to near gale-force winds near the center. Environmental conditions are expected to become more conducive for additional development, and a tropical depression is likely to form by the weekend while moving generally westward at about 20 mph across the tropical Atlantic. This system is expected to reach portions of the Leeward Islands late Saturday or early Sunday, and interests there should monitor its progress. ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 56W, south of 20N and it is moving W at 15-20 kt. Recent scatterometer satellite data and visible imagery show a broad surface curvature associated with this wave. Fresh to locally strong NE winds is noted from 17N to 22N and between 51W and 57W. Scattered showers are noted where the wave interacts with the ITCZ from 08N to 10N between 54W and 56W. A Caribbean tropical wave has its axis along 76W, south of 16N and it is moving W at around 15 kt. No significant showers or thunderstorms are noted with this tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea near 10N15W to 07N20W to 10N38W to 10N46W. The ITCZ continues from 10N47W to 09N55W and then from 09N57W to the mouth of the Orinoco River in NE Venezuela near 09N61W. Scattered moderate convection is noted within 200 nm of the coast of Africa from 04N to 10N and north of the monsoon trough between 27W and 31W. Scattered moderate convection is also found south of the ITCZ to the NE coast of South America, W of 43W. Scattered moderate convection is noted north of the ITCZ, between 57W and the Windward Islands. ...GULF OF MEXICO... An upper level trough is supporting scattered showers and isolated thunderstorm across the northern Gulf of Mexico, mainly between 84W and 93W. A surface trough is located in the central Bay of Campeche along 94W and south of 22N. Scattered moderate convection is noted near the trough axis. The rest of the basin enjoys fairly tranquil weather conditions. South of 25N, gentle to moderate E-SE breezes and 2-4 ft seas prevail in the basin, while light to gentle E-SE breezes and 1-3 ft seas are prevalent elsewhere. For the forecast, Tropical Depression Fred is near 20.9N 74.4W 1013 mb at 11 AM EDT moving WNW at 12 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred is expected to move across the eastern Straits of Florida as a tropical storm by Fri night, enter the far southeast Gulf of Mexico on Sat, and move northward along the far eastern Gulf into early next week. Meanwhile, moderate to fresh E winds will pulse off the northwest Yucatan Peninsula into the Bay of Campeche tonight and Fri night in association with a trough that forms late in the day. Elsewhere, gentle to moderate winds and slight seas will persist through the period. ...CARIBBEAN SEA... Aside from the convection affecting Hispaniola and surrounding waters due to Tropical Depression Fred, fairly tranquil weather conditions prevail across the Caribbean Sea. Moderate to fresh trades are found E of 75W with seas of 5-7 ft. Gentle to moderate trades prevail in the rest of the basin. Seas are 3-5 ft in the SW Caribbean and 1-3 ft in the NW Caribbean and Gulf of Honduras. For the forecast, Tropical Depression Fred is near 20.9N 74.4W 1013 mb at 11 AM EDT moving WNW at 12 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred is expected to remain north of the Caribbean, and will not have in major impact on the basin. Moderate to occasionally fresh winds will persist across most the eastern and central Caribbean as Fred continues to move away from the area and high pressure builds to the north. Light to gentle breezes and slight seas will persist elsewhere. Looking ahead, a fairly strong tropical wave will move into the Windward Islands by Sat night, and into the north central Caribbean by Mon. Breezy winds with showers can be expected. ...ATLANTIC OCEAN... A surface trough in the W Atlantic extends from 31N69W to the eastern Bahamas near 23N74W. The trough and tropical moisture being propelled northward by the circulation of Fred are interacting with an upper level low near 29N64W and another one near Florida, resulting in scattered moderate to isolated strong convection from 23N to 29N and between 65W to 79W. Another surface trough extends from 27N45W to 20N48W and it not producing any significant convection. Outside of the deep tropics, the rest of the basin enjoys fairly tranquil weather conditions. Moderate to fresh easterlies and 6-8 ft seas are present S of 25N, while gentle to moderate easterlies are 3-6 ft seas prevail in the rest of the basin. For the forecast, Tropical Depression Fred is near 20.9N 74.4W 1013 mb at 11 AM EDT moving WNW at 12 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will move to 21.8N 76.2W this evening, 22.8N 78.3W Fri morning, then strengthen to a tropical storm near 23.8N 79.9W Fri evening. Fred will cross the eastern Straits of Florida and into the far southeast Gulf of Mexico by Fri night. Elsewhere, mostly moderate E to SE winds and moderate seas will persist between Fred and the Bermuda-Azores high farther to the northeast in the north central Atlantic. $$ DELGADO