000 AXNT20 KNHC 190555 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Thu Oct 19 2023 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 0525 UTC. ...SPECIAL FEATURES... Tropical Storm Tammy is near 13.4N 54.2W at 2 AM EDT, and is moving west at 15 kt. Maximum sustained winds are 35 kt with gusts to 45 kt, and the minimum central pressure is 1006 mb. Peak seas are currently around 18 ft. Numerous moderate isolated strong convection is noted from 08N to 15N and between 50W and 55W. A turn toward the west-northwest is forecast by tonight, followed by a turn toward the northwest Friday night or Saturday. On the forecast track, the center of Tammy will move near or over the Leeward Islands Friday and Saturday. Additional strengthening is forecast during the next couple of days and Tammy could be near hurricane intensity by the end of the weekend. Swells generated by Tammy will begin affecting portions of the Lesser Antilles later today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. Heavy rains from Tammy will begin to affect the northern Windward and Leeward Islands on Friday, spreading into the British and U.S. Virgin Islands and Puerto Rico over the weekend. This rainfall may produce isolated flash and urban flooding, along with isolated mudslides in areas of higher terrain. 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 Tammy NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the tropical Atlantic through the coast of Guinea-Bissau near 12N16W and continues southwestward to 05N29W and then to 02N40W. The ITCZ extends from 02N40W to 02N50W. Numerous moderate to isolated strong convection is observed from 02N to 12N and between 17W and 33W. ...GULF OF MEXICO... The Gulf of Mexico remains under the influence of a 1020 mb high pressure system positioned over the Big Bend region of Florida. No deep convection is present across the basin due to a dry continental airmass. Moderate to fresh NE winds and seas of 2-4 ft are evident in the Florida Straits and the eastern Bay of Campeche. Elsewhere, moderate or weaker winds and 1-3 ft seas are prevalent. For the forecast, high pressure will continue to dominate the Gulf waters providing gentle to moderate anticyclonic winds through Thu night. A frontal system will bring fresh winds to the NE Gulf Fri and Fri night. Benign conditions will then return over the weekend as high pressure builds back in. ...CARIBBEAN SEA... Please see the Special Features section above for more details on Tropical Storm Tammy located east of the Lesser Antilles. A stationary front stretches from eastern Cuba to the Bay Islands and Belize. Scattered moderate convection is seen on satellite imagery within 150 nm to the east of the boundary. Moderate to locally strong northerly winds and seas of 4-7 ft are found behind the frontal boundary. A few showers and isolated thunderstorms are noted within 120 nm of the coasts of Nicaragua, Costa Rica and western Panama. No deep convection is affecting the remainder of the basin. Meanwhile, the pressure gradient between the ridge north of the islands and lower pressures in northern South America support fresh to strong easterly trade winds in the south-central Caribbean. Wave heights of 4-7 ft are present in the area described. Elsewhere, moderate or weaker winds and 2-4 ft seas prevail. For the forecast, Tropical Storm Tammy is near 13.0N 53.1W at 11 PM EDT, and is moving west at 15 kt. Maximum sustained winds are 35 kt with gusts to 45 kt, and the minimum central pressure is 1006 mb. Tammy will move to 13.2N 55.0W Thu morning, 13.7N 56.8W Thu evening, 14.3N 58.6W Fri morning, 15.4N 60.3W Fri evening, 16.8N 61.6W Sat morning, and 18.4N 62.5W Sat evening. Tammy will strengthen to a hurricane near 22.0N 63.4W late Sun. A stationary front extends from eastern Cuba to the Gulf of Honduras. The front should remain in place through tonight before dissipating on Thu. Fresh to locally strong NE winds and seas of 8 ft will persist over the NW Caribbean W of the front through tonight as high pressure builds over the area. ...ATLANTIC OCEAN... Please see the Special Features section above for more details on Tropical Storm Tammy located east of the Lesser Antilles. A stationary front enters the tropical Atlantic near 31N61W and continues southwestward to the SE Bahamas and NE Cuba. Just ahead of the frontal boundary, north of 24N, is a surface trough associated with the remnants of former tropical cyclone Sean. Scattered moderate to isolated strong convection is affecting the waters within 120 nm of the frontal boundary. A recent scatterometer satellite pass captured fresh to strong NE winds behind the aforementioned front. Seas in the area behind the front are 3-6 ft. Farther east, an upper level low in the NE Caribbean Sea contributing to divergence aloft and moisture associated with Tropical Storm Tammy result in scattered moderate to isolated strong convection from 15N to 24N and between 53W and 62W. Fresh to strong easterly winds and seas of 5-8 ft are occurring in the area described. The remainder of the tropical Atlantic is dominated by a 1023 mb high pressure system near 30N47W that suppresses the development of deep convection outside of the deep tropics. Moderate or weaker winds and moderate seas are prevalent in the central and eastern Atlantic outside of the influence of Tammy. For the forecast W of 55W, Tropical Storm Tammy is near 13.0N 53.1W at 11 PM EDT, and is moving west at 15 kt. Maximum sustained winds are 35 kt with gusts to 45 kt, and the minimum central pressure is 1006 mb. Tammy will move to 13.2N 55.0W Thu morning, 13.7N 56.8W Thu evening, 14.3N 58.6W Fri morning, 15.4N 60.3W Fri evening, 16.8N 61.6W Sat morning, and 18.4N 62.5W Sat evening. Tammy will strengthen to a hurricane near 22.0N 63.4W late Sun. A stationary front extends from 31N61W to eastern Cuba. The front will remain in place before dissipating Thu. High pressure will build over the area in the wake of the front. The next frontal system will move offshore the southeastern United States Fri night. Fresh to strong winds and rough seas are forecast north of 27N Fri night through Sat night with this system. $$ DELGADO