209 AXNT20 KNHC 131807 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1800 UTC. ...SPECIAL FEATURES... Tropical Depression Fred is moving along the northern coast of Cuba at 22.3N 78.9W at 13/1800 UTC or about 245 nm southeast of Key West, Florida. It is moving WNW at 10 kt with an 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 9-12 ft range. Latest satellite imagery depict most of the convection over the eastern quadrant of Fred, affecting portions of Cuba, Jamaica and the Bahamas. Fred is expected to continue moving along or near the north coast of central Cuba through tonight, be near the Florida Keys on Saturday, and move near or west of the west coast of the Florida peninsula Saturday night and Sunday. Little change in strength is expected today. After that, slow strengthening is expected, and Fred could become a tropical storm again tonight or Saturday. 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. Potential Tropical Cyclone Seven is located at 15.3N 50.3W at 13/1800 UTC or about 1245 nm east of the Leeward Islands. It is moving W at 18 kt with an estimated minimum central pressure of 1010 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Wave heights with this system are in the 7-9 ft range. The disturbance is producing a large area of showers and thunderstorms, mainly to the west of the center. On the forecast track, the system is expected to approach the Leeward Islands on Saturday, move over the Leeward Islands Saturday night and Sunday, and then be near the Virgin Islands and Puerto Rico Sunday night and Monday. Gradual strengthening is forecast during the next couple of days, and the disturbance is expected to become a tropical storm by Saturday. 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. ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 23W, south of 21N, and it is moving W at 10-15 kt. No significant convection is associated to this wave. Another Atlantic tropical wave has its axis along 48W, south of 21N, and it is moving W at around 15 kt. Please see the Special Features for information on Potential Tropical Cyclone Seven for information on the convection near this wave. A Caribbean tropical wave has its axis along 63W, south of 23N, and it is moving W at around 15-20 kt. Scattered moderate convection is noted within 150 nm E of the wave axis from 19N to 23N. Scattered moderate convection is also noted near the wave axis in the SE Caribbean. Another Caribbean tropical wave has its axis along 81W, south of 16N, extending into the E Pacific Ocean. It is moving W at 10 to 15 kt. Scattered showers and isolated thunderstorms are noted between the wave axis and the NW coast of Colombia from 08N to 12N. ...MONSOON TROUGH/ITCZ... THe monsoon trough extends across the coast of Sierra Leone near at 09N13W to 10N19W and to 07N32W. The ITCZ then continues from 07N33W to near 07N39W. Scattered moderate convection is noted from 03N to the monsoon trough and between the coast of Africa to 25W. ...GULF OF MEXICO... Upper level forcing over the N Gulf of Mexico is enhancing the development of scattered showers and thunderstorms, especially within 150 nm of the coasts of Louisiana and SE Texas. A weak trough over the central Bay of Campeche extending from 17N92W to 21N94W is generating isolated moderate convection within 70 nm of the coast of Veracruz. Gentle to moderate easterly breezes and 1-3 ft prevail across the Gulf. For the forecast, Tropical Depression Fred near 22.3N 78.4W 1013 mb at 11 AM EDT moving WNW at 10 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will move to 23.0N 79.7W this evening, strengthen to a tropical storm near 24.2N 81.3W Sat morning, 25.6N 82.5W Sat evening, 27.2N 83.6W Sun morning, 28.7N 84.6W Sun evening, and inland to 30.2N 85.4W Mon morning. Fred will weaken to a tropical depression while moving inland over 33.0N 86.5W on early Tue. ...CARIBBEAN SEA... Aside from the convection associated to Fred and to the waves described in the Tropical Waves section, the rest of the basin enjoys fairly tranquil weather conditions. E of 79W, moderate to fresh trades and seas of 4-6 ft prevail. Gentle to moderate trades and seas of 2-4 ft are prevalent elsewhere in the Caribbean Sea. For the forecast, Potential Tropical Cyclone Seven near 15.3N 49.3W 1010 mb at 11 AM EDT moving W at 18 kt. Maximum sustained winds 30 kt gusts 40 kt. Seven will move to 15.7N 52.0W this evening, 16.2N 55.9W Sat morning, 16.7N 59.6W Sat evening, 17.2N 63.0W Sun morning, 17.8N 66.0W Sun evening, and inland to 18.4N 68.7W Mon morning. Seven will change little in intensity as it moves to 20.0N 73.5W by early Tue. ...ATLANTIC OCEAN... A trough extends from 31N74W to the NW Bahamas and an upper level low is located over SW Florida, resulting in scattered showers near the trough axis and off NE Florida, mainly within 70 nm of the coast. A weak trough extends from a low pressure system near 36N33W to 29N45W and it is only producing a few showers near the trough axis. Tranquil weather conditions are prevalent across the rest of the tropical Atlantic under a broad Bermuda-Azores ridge. South of 25N, moderate to fresh easterly breezes and 5-7 ft seas prevail. North of 25N, gentle to moderate winds and 3-7 ft are prevalent. For the forecast west of 65W, Potential Tropical Cyclone Seven near 15.3N 49.3W 1010 mb at 11 AM EDT moving W at 18 kt. Maximum sustained winds 30 kt gusts 40 kt. Seven will move to 15.7N 52.0W this evening, 16.2N 55.9W Sat morning, 16.7N 59.6W Sat evening, 17.2N 63.0W Sun morning, 17.8N 66.0W Sun evening, and inland to 18.4N 68.7W Mon morning. Seven will change little in intensity as it moves to 20.0N 73.5W by early Tue. $$ DELGADO