000 AXNT20 KNHC 150607 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sun Aug 15 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... The remnants of Fred are in the SE Gulf of Mexico, off the NW coast of Cuba, near 23.8N 84.3W at 0300 UTC, or about 110 nm W-NW of Havana, Cuba. It is moving WNW at 8 kt with an estimated minimum central pressure at 1012 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt occurring in squalls N and NE of the center. Wave heights with the remnants of Fred are in the 8-10 ft range. Latest satellite imagery shows scattered showers and thunderstorms from W Cuba northward to the Florida Keys. Fred is expected to gradually turn toward the northwest today, then north tonight and Monday with some strengthening. This will bring Fred or its remnants into the E central Gulf tonight and Monday, and move inland over the northern Gulf coast Monday night. Fred is expected to redevelop into a tropical depression later today and then a tropical storm near 26.8N 86.9W late tonight or early Monday. 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 NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Storm Grace is over the Lesser Antilles near 16.8N 62.4W at 0300 UTC or about 145 nm E-SE of St. Croix. It is moving WNW at 17 kt, with an estimated minimum central pressure of 1010 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Wave heights with this system are in the 9-12 ft range. Despite being a small tropical storm, interaction with a mid-level trough near 16N64W is producing numerous showers and scattered thunderstorms to the W and SW of the center, over the Leeward Islands and E Caribbean Sea. Grace is forecast to move toward the west-northwest with a gradual decrease in forward speed during the next several days. This will bring Grace very close to the Virgin Islands later today and Puerto Rico tonight, then over the Dominican Republic and Haiti on Monday and Monday night, and then between the southeastern Bahamas and Cuba on Tuesday. Some strengthening is forecast through tonight. Grace is likely to weaken while it moves over Hispaniola Monday and Monday night. 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 NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... An Atlantic tropical wave is along 23W from 19N southward and moving W at 10 to 15 kt. Scattered moderate convection is noted from 06N to 09N and between 19W and 26W. Another Atlantic tropical wave is near 40W from 20N southward and moving W at 20 to 25 kt. Scattered moderate convection is seen from 06N to 08N between 37W and 43W. A Caribbean tropical wave is along 72W from 25N southward across Haiti into NW Venezuela, and moving W at 15 to 20 kt. Recent scatterometer satellite data continue to depict a broad surface trough, especially on the northern portion of the wave. Aided by an upper-level trough SW of Bermuda near 28N67W, scattered showers and isolated thunderstorms are present from 22N to 25N between 66W and 73W, and also S of Hispaniola from 15N to 17N between 70W and 74W. Another tropical wave is near 88W from 19N southward across the Yucatan Peninsula and Guatemala into the E Pacific, and moving W near 15 kt. Numerous moderate to strong convection is flaring up along the S coast of Guatemala and El Salvador. ...MONSOON TROUGH/ITCZ... A monsoon trough exits along the coast of Mauritania near 20N16W through a low pressure centered near 12N22W to 06N40W. The ITCZ then continues from 06N40W to 05N53W over N French Guiana. Numerous moderate to isolated strong convection is noted near and S of the monsoon trough from 10N to 17N between the African coast and 19W. Scattered moderate convection is found near the low from 10N to 14N between 20W and 25W, and also near the monsoon trough from 01N to 07N between 27W and 36W. Scattered moderate to isolated strong convection is seen N of the ITCZ from 06N to 09N between 48W and 56W, N of French Guiana and Suriname. ...GULF OF MEXICO... Refer to the Special Features section for information on the remnants of Fred. An upper level low over the NE Gulf near 29N85W is triggering scattered showers and isolated thunderstorms over the NE Gulf including the Big Band area and central W coast of Florida. Moderate to locally fresh S to SE winds and seas of 3 to 6 ft are expected near these thunderstorms. Gentle to moderate NE to E winds and seas at 2 to 4 ft prevail for the rest of the Gulf. For the forecast, the remnants of Fred near 23.8N 84.3W 1012 mb at 11 PM EDT or 0300 UTC moving WNW at 8 kt. Maximum sustained winds 30 kt gusts 40 kt. Fred will move to near 25.3N 85.7W Sun morning with maximum sustained winds 35 kt gusts 45 kt, to near 26.8N 86.9W Sun evening, to near 28.3N 87.8W Mon morning with maximum sustained winds 45 kt gusts to 55 kt, to near 29.7N 88.0W Mon evening, and weaken to a depression inland near 31.4N 87.9W Tue morning. Fred will dissipate late on Wed. Tropical Storm Grace currently entering the far eastern Caribbean Sea is forecast to move near the northern coast of Cuba and Straits of Florida Wed and Wed night and into the southeastern Gulf of Mexico Thu and Thu night. ...CARIBBEAN SEA... Refer to the Special Features section for information on Tropical Storm Grace and the Tropical Waves section for convection in the Caribbean Basin. Convergent trade winds are producing scattered showers and a few thunderstorms N of Colombia and Panama. Moderate with locally fresh trades and seas of 4 to 6 ft are present S central and SE Caribbean, while gentle to moderate trades and seas of 3 to 4 ft prevail across the rest of the basin. For the forecast, Tropical Storm Grace near 16.8N 62.4W 1010 mb at 11 PM EDT or UTC 0300 moving WNW at 17 kt. Maximum sustained winds 35 kt gusts 45 kt. Grace will move to near 17.3N 64.6W Sun morning, inland over Puerto Rico near 18.1N 67.0W Sun evening, inland over the eastern Dominican Republic near 18.7N 69.1W Mon morning, inland over the Dominican Republic near 19.3N 70.9W Mon evening, then over water near 20.2N 73.2W Tue morning with maximum sustained winds 35 kt gusts 45 kt and to near 21.2N 75.8W Tue evening. Grace will change little in intensity as it moves across the Straits of Florida to near 23.7N 81.0W by late Wed and into the southeastern Gulf of Mexico thereafter. ...ATLANTIC OCEAN... Refer to the Special Features section for information on Tropical Storm Grace. An upper-level low SE of Bermuda near 30N56W is causing scattered showers and a few thunderstorms N of 27N between 51W and 57W. Divergent flow E and SE of an upper-level low of the NE Gulf is coupling with convergent SE winds to trigger scattered showers and isolated thunderstorms over SE Florida and off the Florida-Georgia coast. For additional convection across the Atlantic Basin, please read the Tropical Waves and Monsoon Trough/ITCZ sections above. The persistent Atlantic ridge over the N Atlantic continues to support light to gentle winds and seas at 2 to 4 ft N of 24N between 31W and 73W. Moderate with locally fresh NE to SE winds and seas of 5 to 7 ft are found N of 19N between the NW African coast and 31W, and also N of 20N between 73W and the Florida- Georgia coast. Gentle to moderate trades and seas of 4 to 6 ft are evident from 10N to 20N between the African coast and the Lesser Antilles. Mainly gentle SE to SW winds and seas of 4 to 5 ft prevail across the remainder of the basin. For the forecast west of 65W, Tropical Storm Grace near 16.8N 62.4W 1010 mb at 11 PM EDT or 0300 UTC moving WNW at 17 kt. Maximum sustained winds 35 kt gusts 45 kt. Grace will move to near 17.3N 64.6W Sun morning, inland over Puerto Rico near 18.1N 67.0W Sun evening, inland over the eastern Dominican Republic near 18.7N 69.1W Mon morning, inland over the Dominican Republic near 19.3N 70.9W Mon evening, then over water near 20.2N 73.2W Tue morning with maximum sustained winds 35 kt gusts 45 kt and to near 21.2N 75.8W Tue evening. Grace will change little in intensity as it moves across the Straits of Florida to near 23.7N 81.0W by late Wed and into the southeastern Gulf of Mexico thereafter. Otherwise, high pressure will persist across the area through the period. $$ Chan