290 AXNT20 KNHC 111757 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed Aug 11 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 1705 UTC. ...SPECIAL FEATURES... Tropical Storm Fred is centered near 18.5N 70.5W at 11/1800 UTC or 30 mi W of Santo Domingo, Dominican Republic. Fred is currently making landfall. The maximum sustained wind speed is 40 kt with gusts to 50 kt. Fred is moving WNW at 14 kt and the estimated minimum central pressure is 1006 mb. Numerous moderate and scattered strong convection is noted within 60 nm NW and 180 nm SE semicircles of Fred. Fred will move across Hispaniola today and tonight, with the mountainous terrain expected to weaken the system to a tropical depression later today. Fred is forecast to emerge off the NW coast of Hispaniola as a tropical depression during the overnight hours. The system is forecast to re-intensify to tropical storm strength Thursday and continue on a WNW track near the north coast of Cuba Thu and Fri, approaching the Florida Straits Fri night. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across portions of Hispaniola today. 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 on Fred. ...TROPICAL WAVES... An Atlantic tropical wave has its axis at 32W, south of 20N, and it is moving W at around 15 kt. The northern part of the wave is embedded in a dry environment, suppressing the development of convection. Scattered moderate convection is noted west of southern part of the wave axis, enhanced by the monsoon trough, from 08N to 14N and between 33W and 38W. This is a disturbance that the National Hurricane Center is tracking for possible tropical development over the next few days. Please see the latest Tropical Weather Outlook from the National Hurricane Center for more information. Another Atlantic tropical wave has its axis at 47W, south of 21N, and moving W at 10-15 kt. This wave is also embedded in an environment of dry air, suppressing the development of convection. A Caribbean tropical wave has its axis at 69W, south of TS Fred, and moving W at around 15 kt. This wave is enhancing the development of showers and thunderstorms over west-central Venezuela and E Colombia. Another Caribbean tropical wave has its axis at 87W, south of 22N, and it is moving W at around 15 kt. Scattered moderate convection is noted within 60 nm of the wave axis in the NW Caribbean Sea. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea-Bissau near 12N16W to 09N25W to 11N37W to 08N48W. The ITCZ then continues from 08N49W to the coast of Guyana near 07N58W. Scattered moderate convection is noted within 200 nm of the coast of Sierra Leone. Scattered moderate to isolated strong convection is also found within 200 nm north of the monsoon trough between 48W and 55W. ...GULF OF MEXICO... The W ridge axis of the subtropical ridge is positioned north of the Gulf of Mexico, allowing for gentle to moderate E-SE winds across the basin. A surface trough is located in the central Bay of Campeche, extending from 22N92W to 17N93W. Isolated moderate convection is noted west of the trough axis. Scattered moderate convection is also found in the N Gulf, within 200 nm of the coasts of SE Louisiana, Mississippi and Alabama. Scattered showers are also noted from 24N to 27N and between 90W and 93W. Seas are 3-4 ft S of 25N and 1-3 ft in the rest of the basin. For the forecast, moderate to fresh E winds will pulse off the NW Yucatan Peninsula into the Bay of Campeche tonight and Thu night in association with a diurnal trough. Elsewhere, a weak surface ridge will prevail along 30N through Thu. Tropical Storm Fred near 18.2N 69.7W 1006 mb at 11 AM EDT moving WNW at 14 kt. Maximum sustained winds 40 kt gusts 50 kt. Fred is expected to move across the Straits of Florida Fri night as a tropical storm, into the SE Gulf of Mexico Sat, and move NW along the far E Gulf through the weekend. ...CARIBBEAN SEA... Please see the Special Features section for further details on Tropical Storm Fred. Outside of Tropical Storm Fred, the only other area of significant convection is found in the SW Caribbean Sea. The E Pacific monsoon trough extends into the Caribbean Sea across S Costa Rica and W Panama. Scattered moderate convection is noted within 100 nm of the coasts of SE Nicaragua, Costa Rica, Panama and NW Colombia. Recent scatterometer satellite data show moderate to fresh trades prevailing in the rest of the central Caribbean. However, there is a localized area of fresh to strong winds in the Windward Passage between Cuba and Haiti. Gentle to moderate trades are prevalent elsewhere in the basin. Seas in the south-central Caribbean are 6-8 ft, while 4-6 ft are found in the north-central Caribbean and 2-4 ft elsewhere. For the forecast, gentle to moderate winds will prevail across most of the basin through the rest of the week. Fresh winds will prevail near the coast of Colombia Thu and Fri. Tropical Storm Fred near 18.2N 69.7W 1006 mb at 11 AM EDT moving WNW at 14 kt. Maximum sustained winds 40 kt gusts 50 kt. Fred is expected to be near or over Hispaniola this afternoon and evening, move near the Turks and Caicos Islands and the southeastern Bahamas on Thursday. Weakening is expected later today and tonight as the center of Fred crosses Hispaniola. ...ATLANTIC OCEAN... Please see Special Features section above for more on Tropical Storm Fred. The broad Bermuda-Azores subtropical ridge dominates the tropical Atlantic. Tropical moisture being propelled northward by the circulation of Fred is interaction with an upper level low near 29N64W, resulting in scattered moderate convection from 21N to 31N and between 58W and 69W. The rest of the basin enjoys fairly tranquil weather conditions. Light to gentle easterlies and seas of 3-5 ft prevail N of 27N. Gentle to moderate easterlies are prevalent elsewhere N of 20N, along with 5-7 ft seas. Over the deep tropics S of 20N, gentle to moderate winds prevail N of 10N, and light to gentle winds are prevalent S of 10N. Seas are in the 5-7 ft range N of 10N and 4-5 ft S of 10N. For the forecast W of 65W, Atlc surface ridge associated with the Bermuda- Azores high will persist with axis N of the area for the next several days. Tropical Storm Fred near 18.2N 69.7W 1006 mb at 11 AM EDT moving WNW at 14 kt. Maximum sustained winds 40 kt gusts 50 kt. Fred is expected to be near or over Hispaniola this afternoon and evening, move near the Turks and Caicos Islands and the southeastern Bahamas on Thursday, and move near or north of the northern coast of central Cuba on Friday. Weakening is expected later today and tonight as the center of Fred crosses Hispaniola. Slow re-intensification is expected beginning Thursday night. $$ DELGADO