047 AXNT20 KNHC 191708 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Sep 19 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 Peter is centered near 17.6N 56.5W at 19/1500 UTC or 380 nm E of the Northern Leeward Islands moving WNW at 15 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peter is under strong SW wind shear, displacing the convection well to the NE of the center. Numerous moderate to isolated strong convection is observed from 16N to 22N and between 50W and 55W. Peter is producing up to 13 ft seas near the center. A gradual decrease in forward speed is is expected through Tuesday. A turn to the northwest is expected to occur by Wednesday. On the forecast track, the center of Peter is expected to pass well north of the Leeward Islands on Monday and Tuesday. Heavy rain and large swells are expected to impact the N Leeward Islands, Virgin Islands and Puerto Rico. Interests across these areas should monitor this system closely. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Offshore Waters Forecasts at https://www.nhc.noaa.gov/marine/offshores.php for more details. Tropical Depression Seventeen is centered near 13.2N 28.8W at 19/1500 UTC or 275 nm WSW of the southernmost Cabo Verde Islands moving NNW at 12 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Strong easterly wind shear is affecting the tropical depression, causing the convection to be displaced to the west of the center. Scattered moderate to isolated strong convection is noted from 10N to 16N and between 28W and 33W. Seas near the center are up to 9 ft. A motion toward the northwest is forecast to begin by tonight and continue through Tuesday. The depression is likely to become a tropical storm tonight or Monday. By Tuesday, environmental conditions are expected to become less conducive for development, and the system is forecast to begin a slow weakening trend. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT2.shtml. For sea conditions near this system, please read the Meteo-France High Seas Forecast at: http://weather.gmdss.org/II.html ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 30W, south of 19N, and it is moving W near 10 kt. The convection in the vicinity of the wave is mainly associated with T.D. Seventeen. ...MONSOON TROUGH/ITCZ... A monsoon trough extends across the Mauritania coast at 18N16W through T.D. Seventeen, and to 06N42W. The ITCZ then continues from 06N43W to 09N48W. Numerous moderate to strong convection is occurring S of the monsoon trough along the coast of Senegal, Gambia, Guinea-Bissau and Guinea in association with a tropical wave that is nearing the African coast. Scattered moderate convection is also found from 04N to 08N and between 37W and 41W. The E Pacific monsoon trough protrudes into the SW Caribbean Sea and it is causing scattered showers and thunderstorms within 80 nm of the N coast of Panama and NW Colombia. ...GULF OF MEXICO... A surface trough continues in the N Gulf, extending from the Big Bend area of Florida to NE Texas, paralleling the southern coast of Louisiana. A few showers and isolated thunderstorms are noted near the trough axis. Another surface trough is located in the W Bay of Campeche, resulting in scattered moderate convection from 21N to 24N and between 95W to the coasts of Veracruz and Tamaulipas. The rest of the basin enjoys fairly tranquil weather conditions. Moderate to locally fresh SE winds are observed in the E Bay of Campeche, while gentle to moderate anticyclonic winds are noted elsewhere. Seas of 1-3 ft are found in the Gulf. For the forecast, weak high pressure will extend across the eastern and central Gulf of Mexico through the early part of the week. This pattern will support continued gentle to moderate winds and mostly slight seas across the Gulf through Tue. Looking ahead, a weak cold front may move into the northwest and north- central Gulf by mid week. ...CARIBBEAN SEA... A few showers are noted in the vicinity of the waters surrounding Jamaica, but this activity appears to be weakening. Satellite- derived wind data depict fresh to strong winds in the area, likely due to strong downdrafts. The rest of the Caribbean Sea enjoys fairly dry weather conditions. A recent scatterometer satellite pass indicate fresh to locally strong trades off the coast of NW Colombia and south of Hispaniola, especially off the Barahona peninsula. Moderate to locally fresh trades are prevalent in the rest of the Caribbean Sea. Seas of 4-7 ft are found in the central and SW Caribbean, while 2-4 ft prevail elsewhere in the basin. For the forecast, Tropical Storm Peter near 17.6N 56.5W 1007 mb at 1500 UTC moving WNW at 15 kt. Maximum sustained winds 40 kt gusts 50 kt. Peter is expected to continue WNW and reach near 19.3N 58.8W tonight, and near 20.2N 61.1W Mon afternoon, then veer more NW through Tue, then turn northward toward Bermuda throughout the rest of the week. As this occurs, trade winds over the south- central Caribbean will diminish over the next several days. Look for associated squalls and thunderstorms to begin affecting the Leeward Islands and adjacent waters today. ...ATLANTIC OCEAN... Please read the Special Features section above for details on Tropical Storm Peter E of the Leeward Islands and Tropical Depression Seventeen WSW of the Cabo Verde Islands. The surface trough over the N Gulf of Mexico spills into the Atlantic waters off the NE coast of Florida, resulting in scattered moderate convection from 27N to 32N and between 76W and the coasts of Florida and Georgia. An upper level low near 23N64W is interacting with a surface trough that extends from 26N59W to 19N60W, causing scattered moderate to isolated strong convection from 22N to 26N and betwen 58W and 62W. A convergent wind flow is resulting in a few showers and isolated thunderstorms along 66W from 22N to 31N. The rest of the tropical Atlantic is dominated by a strong subtropical ridge anchored near the Azores, maintaining fairly tranquil weather conditions. Recent scatterometer satellite data show strong to near-gale winds to the N of the center of T.S. Peter from 18N to 21N and between 54W and 58W. Moderate to locally fresh winds prevail across the rest of the tropical Atlantic. Seas are 3-6 ft W of 60W and 5-8 ft E of 60W. The Cumbre Vieja volcano in the island of La Palma in the Canary Islands erupted around 1410 UTC. The ash plume is expected to remain below 5000 ft and drift SE, causing a reduction in visibility. Mariners should exercise caution. For the forecast west of 60W, Tropical Storm Peter near 17.6N 56.5W 1007 mb at 1500 UTC moving WNW at 15 kt. Maximum sustained winds 40 kt gusts 50 kt. Peter is expected to continue WNW with little change in strength, reaching near 19.3N 58.8W tonight, near 20.2N 61.1W Mon afternoon, then veer more NW and reach near 22.5N 66.3W Tue evening, and 23.8N 67.0W Wed morning. Peter will then move more northward in the general direction of Bermuda through Sat. Elsewhere west of 70W, gentle to moderate winds and slight to moderate seas will persist over open waters through the early part of the week, with swell to 8 ft associated with the tropical storm reaching the waters east of 72W by Wed. $$ DELGADO