000 AXNT20 KNHC 130607 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0630 UTC. ...SPECIAL FEATURES... Tropical Depression Fred is centered near far E Cuba at 21.3N 75.1W at 13/0000 UTC or 450 nm ESE of Key West Florida. It is moving WNW at 7 kt with estimated minimum central pressure at 1013 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are currently 9 ft. Scattered to numerous moderate convection is seen over E Cuba and adjacent waters. Fred is forecast to strengthen to a tropical storm near E Cuba Fri morning before turning NW toward the Florida Keys on Fri night and Sat morning. Tropical Storm conditions and locally heavy rain are possible along the N coastline of E and central Cuba Fri and Fri night, Florida Keys on Saturday. 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. Satellite ASCAT scatterometer data and IR imagery tonight reveal the area of low pressure has drifted to near 14N45W about 920 nm E of the Lesser Antilles. This system remains to be disorganized with scattered moderate to isolated strong convection mainly to the W, mainly enhanced by a tropical wave in the vicinity. Despite this, environmental conditions are expected to be favorable for gradual development and it could become a tropical depression by this weekend near the Lesser Antilles. Please read the latest NHC Tropical Weather Outlook at hurricanes.gov for more details. ...TROPICAL WAVES... An Atlantic tropical wave is just offshore of the coast of Africa along 19W from 20N southward and moving W at 5 to 10 kt. Scattered moderate convection is noted from 04N to 08N between 15W and 22W. Another Atlantic tropical wave is near 44W from 20N southward and moving W near 15 kt. Scattered moderate and isolated strong convection is seen from 04N to 16N between 45W and 50W. A third Atlantic tropical wave is along 56W from 23N southward and moving W near 15 kt. Scattered moderate convection is present from 19N to 22N between 56W and 59W. This wave will approach the Lesser Antilles on Friday and increase the chance of showers and thunderstorms there. A Caribbean tropical wave is near 78W from 15N southward across E Panama into the E Pacific Ocean, and moving W at 10 to 15 kt. Scattered showers and isolated thunderstorms are occurring near and just S of Jamaica. ...MONSOON TROUGH/ITCZ... A monsoon trough extends across the coast of Africa near the Senegal-Gambia border at 14N16W to 08N19W to 06N29W. An ITCZ then continues from 06N29W to near 09N44W. Scattered moderate to isolated strong convection is found near the monsoon trough from 08N to 15N between the African coast and 16W. Scattered moderate convection is present N of the ITCZ from 06N to 11N between 28W and 35W. ...GULF OF MEXICO... An upper-level trough is over the E Gulf near 27N83W is triggering scattered showers and isolated thunderstorms across the E Gulf and S 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 is along the north coast of Cuba near 21.5N 75.6W 1013 mb at 11 PM EDT moving WNW at 8 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred is forecast to strengthen to a tropical storm early Fri and move across the Straits of Florida through Sat afternoon reaching the southeastern Gulf waters near 25.5N 82.1W Sat evening with maximum sustained winds 40 kt gusts 50 kt. Fred is forecast to reach near 27.2N 83.1W early Sun with maximum sustained winds 45 kt guts 55 kt, to near 29.1N 84.2W Sun evening and inland to near 31.8N 85.6W by Mon evening with maximum sustained winds 35 kt gusts 45 kt. Meanwhile, moderate to fresh east winds off the northwest Yucatan Peninsula are due to the typical Yucatan Peninsula trough that develops each afternoon. Elsewhere, 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 21.5N 75.6W 1013 mb at 11 PM EDT is moving WNW at 8 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will strengthen to a tropical storm near 22.2N 77.1W Fri morning with maximum sustained winds 35 kt gust 45 kt, move to near 23.0N 79.0W Fri evening and across the rest of the Straits of Florida reaching the southeastern Gulf of Mexico by Sat evening. Numerous squalls and thunderstorms will spread westward across most of Cuba through, with some of this activity possibly reaching the far northwestern Caribbean Sea. 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 breezes and slight seas will persist elsewhere. A tropical wave near 59W will cross the Lesser Antilles early Fri, then move across the eastern Caribbean through early Sat, the central Caribbean through late Sun and the western Caribbean early next week. Scattered showers and thunderstorms will accompany the wave. Low pressure located well east of the Lesser Antilles is pressure is expected to reach portions of the Leeward Islands late Sat or early Sun and the north-central Caribbean Mon 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 N 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 21.5N 75.6W 1013 mb at 11 PM EDT is moving WNW at 8 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will strengthen to a tropical storm near 22.2N 77.1W Fri morning with maximum sustained winds 35 kt gust 45 kt, move to near 23.0N 79.0W Fri evening, then intensify slightly as it moves to near 24.2N 80.6W Sat morning with maximum sustained winds 40 kt gusts 50 kt and maintain intensity as it moves across the rest of the Straits of Florida and to the southeastern Gulf of Mexico near 25.5N 82.1W Sat evening. Numerous squalls and thunderstorms associated with Fred over the far southern part west of 71W will gradually shift westward through Sat. The northern part of a tropical wave will move across the far southern waters Fri through late Sun. Low pressure located well east of the Lesser Antilles is pressure is expected to reach portions of the Leeward Islands late Sat or early Sun and the north-central Caribbean Mon as a possible tropical cyclone. Expect strong gusty winds along with scattered to numerous showers and thunderstorms with this system. $$ Chan