000 AXNT20 KNHC 191745 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... Tropical Storm Tammy is centered near 13.6N 55.7W at 19/1500 UTC or 370 nm ESE of Guadeloupe, moving WNW at 13 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Peak seas are currently around 18 ft. Numerous moderate to isolated strong convection is noted from 07N to 15N and between 51W and 56W. A slower west- northwest motion is expected through tonight. A turn toward the northwest is forecast on Friday, and this motion should continue into the weekend. On the forecast track, the center of Tammy will move near or over the Leeward Islands Friday and Saturday. Gradual strengthening is expected during the next few days, and Tammy is forecast to be at or near hurricane intensity when it moves near the Leeward Islands. 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 near 10N14W and continues southwestward to 08.5N25W and then to 02N37W. The ITCZ extends from 02N37W to 01N47W. Numerous moderate to isolated strong convection is observed from 05N to 14.5N between 19W and 34W. ...GULF OF MEXICO... The Gulf of Mexico remains under the influence of a surface ridge anchored by a 1023 mb high pressure center over the Carolinas, which is providing E to SE gentle to moderate winds and slight seas basin-wide. For the forecast, high pressure extending from the Carolinas to the Texas coast will shift south through Sat ahead of a weak cold front expected to move into the northeast Gulf Fri night. The front will weaken as it moves slowly across the eastern Gulf into Mon, then stall and dissipate from southwest Florida to the north Texas coast by Sun night or early Mon. ...CARIBBEAN SEA... Please see the Special Features section above for more details on Tropical Storm Tammy located east of the Lesser Antilles. Tropical Storm Tammy is centered near 13.6N 55.7W at 19/1500 UTC moving WNW at 13 kt. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Estimated minimum central pressure is 1003 mb. The stationary front between eastern Cuba and the Gulf of Honduras it now dissipating. However, scattered moderate convection is depicted along the weakening front. Additionally, winds along the front are gentle to moderate, with seas 3 to 5 ft. The eastern end of the Eastern Pacific Monsoon Trough is producing scattered to numerous moderate to isolated strong convection in the offshore waters of Nicaragua, Costa Rica, and Panama. The pressure gradient between the Atlantic subtropical ridge and lower pressure in NW Colombia supports fresh to locally strong easterly trade winds in the south-central Caribbean and wave heights of 4-8 ft. Elsewhere, moderate or weaker winds and slight to moderate seas prevail. For the forecast, Tropical Storm Tammy is near 13.6N 55.7W at 11 AM EDT, and is moving west-northwest at 13 kt. Maximum sustained winds are 50 kt with gusts to 60 kt, and the minimum central pressure is 1003 mb. The center of Tammy will move to 14.0N 57.4W this evening, 14.8N 59.2W Fri morning, and 16.0N 60.9W Fri evening near Guadeloupe. Tammy is forecast to strengthen to a hurricane near 17.5N 62.1W Sat morning, continue across the northern Leeward Islands and reach 19.0N 62.8W Sat evening, then move north of the region through the early part of the week. Elsewhere, a weakening stationary front extending from eastern Cuba to the Gulf of Honduras will dissipate later today. Fresh to locally strong trade winds over the south-central and southwest Caribbean will diminish tonight. ...ATLANTIC OCEAN... Please see the Special Features section above for more details on Tropical Storm Tammy located east of the Lesser Antilles. Tropical Storm Tammy is centered near 13.6N 55.7W at 19/1500 UTC moving WNW at 13 kt. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Estimated minimum central pressure is 1003 mb. A stationary front extends from 31N60W to eastern Cuba supporting scattered showers in the southern Bahamas as well as Turks and Caicos. Ahead of the front and well to the NE of Puerto Rico, upper level diffluence supports a broad area of numerous moderate to scattered strong convection from 17N to 25.5N between 57.5W and 64W. The remainder subtropical Atlc is under the influence of a ridge supporting mainly gentle to moderate winds and moderate seas. For the forecast W of 55W, Tropical Storm Tammy is near 13.6N 55.7W at 11 AM EDT, and is moving west-northwest at 13 kt. Maximum sustained winds are 50 kt with gusts to 60 kt, and the minimum central pressure is 1003 mb. Tammy will move through the Leeward Islands through Sat, intensifying to hurricane strength by Sat morning. Tammy will reach 19.0N 62.8W Sat evening then continue to move north of the Leeward Islands to 20.5N 63.3W by Sun morning. Tammy will change little in intensity as it moves to the north- northeast across the waters east of 65W through the early part of the week. Elsewhere, a stationary front from 31N60W to eastern Cuba will weaken today before dissipating. 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. $$ KRV