000 AXNT20 KNHC 201249 TWDAT Tropical Weather Discussion...Update NWS National Hurricane Center Miami FL 1205 UTC Fri Aug 20 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 0900 UTC surface analysis and satellite imagery through 1200 UTC. Updated Special Features Section Below ...SPECIAL FEATURES... Grace is now a hurricane and centered near 20.6N 93.7W at 20/1200 UTC or 140 nm ENE of Veracruz Mexico moving W at 13 kt. Estimated minimum central pressure is 983 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Peak seas are currently 26 ft. Numerous moderate to strong convection is noted within near the center from 19N to 22N between 92W and 96W. Grace will move inland to 20.3N 97.4W Saturday morning, and weaken to a tropical storm near 19.8N 99.7W Sat afternoon, weaken to a remnant low near 19.4N 102.2W Sun morning, and dissipate Sun afternoon. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more details. Tropical Storm Henri is centered near 30.0N 73.7W at 20/1200 UTC or 325 nm SSE of Cape Hatteras North Carolina and moving WNW at 8 kt. Estimated minimum central pressure is 995 mb. Maximum sustained wind speed is 65 kt with gusts to 65 kt. Peak seas are currently 24 ft. Numerous moderate to isolated strong convection is noted from 28N to 31N between 72W and 75W. Henri will move to 31.0N 73.5W this afternoon, then north of the area to 33.0N 72.9W Sat morning, and strengthen to a hurricane well north of the area near 36.1N 71.8W Sat afternoon. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details. ...TROPICAL WAVES... A tropical wave is in the Atlantic Ocean along 32W south of 21N, moving W at 15 to 20 kt. Scattered moderate convection is noted from 06N to 15N between 30W and 40W. A tropical wave is in the Atlantic Ocean along 42W south of 21N, moving W at around 15 kt. Scattered moderate convection is noted from 06N to 11N between 40W and 50W. A tropical wave is in the far eastern Caribbean Sea along 63W south of 22N, moving W at 15 to 20 kt. Scattered showers and isolated thunderstorms are near the tropical wave axis, mainly from 12N to 17N between 59W and 66W. Moisture associated with this wave will continue to impact the eastern Caribbean and parts of the Lesser Antilles today. A tropical wave is in the Caribbean Sea along 75W south of 22N, moving W at 15 to 20 kt. Limited convection is over water however scattered showers and thunderstorms are noted over portions of northern Colombia and far northwest Venezuela, including the Lake Maracaibo region. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Mauritania near 18N16W to 13N30W to 10N51W. The ITCZ then extends from 10N51W to 10N61W. In addition to the convection associated with the tropical waves, scattered moderate convection is observed from 10N to 16N between the coast of Africa and 23W. The eastern Pacific monsoon trough extends into the southwest Caribbean Sea from near the Costa Rica-Panama border to northern Colombia. Scattered moderate and isolated strong convection is noted from 09N to 13N between 76W and 81W, and from 10N to 15N between 81W and 84W. ...GULF OF MEXICO... Refer to the Special Features section above for details on Tropical Storm Grace. Outside of the influence of Tropical Storm Grace, fairly tranquil weather conditions are observed across the Gulf of Mexico with 1018 mb high pressure analyzed near 29N87W. Light to gentle anticyclonic winds are in the northeast Gulf under the high along with seas of 2 to 4 ft, with worsening conditions elsewhere toward Grace. For the forecast, Grace will strengthen to a hurricane near 20.6N 95.2W this afternoon, move inland to 20.3N 97.4W Sat morning, and weaken to a tropical storm near 19.8N 99.7W Sat afternoon, weaken to a remnant low near 19.4N 102.2W Sun morning, and dissipate Sun afternoon. High pressure will build in the wake of Grace and prevail through early next week. ...CARIBBEAN SEA... Fresh to strong E-SE winds are noted in the Gulf of Honduras region early this morning due to a locally tight pressure gradient, along with seas of 5 to 8 ft. Mainly moderate to locally fresh trades prevail elsewhere along with seas of 3 to 6 ft, locally to 7 ft offshore of the northern coast of Colombia. Scattered showers and isolated thunderstorms are noted in the Caribbean from north of the A-B-C Islands to south of Puerto Rico and Hispaniola between 65W and 71W, with similar activity in the western Caribbean. For the forecast, moderate to fresh trade winds will dominate elsewhere, except for nightly pulsing locally fresh to strong winds in the Gulf of Honduras through Sat night, and also in the central Caribbean early next week. ...ATLANTIC OCEAN... Refer to the Special Features section above for details on Tropical Storm Henri. Tropical Storm Henri is the only source of deep convection noted across the tropical Atlantic as the basin remains under the control of a broad 1022 mb subtropical ridge anchored near 32N54W. Moderate to fresh N-NE winds are noted in the waters surrounding the Canary Islands and off the northwest coast of Africa. Seas in this region are in the 6 to 9 ft range. Another area of moderate to fresh easterlies is observed from 15N to 29N and between 35W and 65W. Seas across this area are mainly 5 to 7 ft, locally to 8 ft near 22.5N78W. Gentle to moderate winds prevail in the rest of the basin with seas of 3 to 6 ft. For the forecast west of 55W, Henri will move to 31.0N 73.5W this afternoon, then north of the area to 33.0N 72.9W Sat morning, strengthening to a hurricane well north of the area near 36.1N 71.8W Sat afternoon. Otherwise, moderate to fresh E to SE winds will prevail E and across the Bahamas Fri through Mon, except for fresh to locally strong winds at night north of Hispaniola and the approaches to the Windward Passage. $$ Chan