000 AXNT20 KNHC 221715 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Oct 22 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 1800 UTC. ...SPECIAL FEATURES... Hurricane Tammy is centered near 19.1N 63.0W at 22/1500 UTC or 50 nm N of Anguilla, moving NW at 8 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Hurricane-force winds extend outward up to 20 nm from the center and tropical-storm-force winds extend outward up to 120 nm. Seas of 12 ft or greater extend out up to 180 nm, especially N of the center where peak seas are near 25 ft. Tammy is moving toward the northwest and this general motion is expected today. A turn toward the north is expected tonight, followed by a north-northeast or northeast motion on Tuesday. Little change in strength is forecast during the next few days. Numerous moderate to strong convection is noted within 60 nm of center. Tammy is slowly pulling away from the northern Leeward Islands. However, there is still a trailing area of showers and thunderstorms that will likely cause heavy rain across portions of the Windward and Leeward Islands throughout the day. These rains may produce isolated flash and urban flooding, along with isolated mudslides in areas of higher terrain. Swells generated by Tammy will continue to affect portions of the Lesser Antilles during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. Please read the latest HIGH SEAS FORECAST issued by National Hurricane Center at web-site https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Hurricane Tammy Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Southwestern Caribbean Sea (AL95): Showers and thunderstorms have become better organized in association with a low pressure system located over the southwestern Caribbean Sea. Gradual development of this system is possible, and a tropical depression could form before the system moves inland over Nicaragua by early Tuesday. Regardless of development, this system could produce heavy rains over portions of Central America during the next couple of days. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone development through 48 hours, and also through 7 days. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. Gale Warning E of 35W: A 998 mb low pressure located over the eastern Atlantic near 36N09W continues to support gale force winds over the marine zones called Madeira and Agadir in the Meteo-France High Seas Forecast area. For more details, refer to the Meteo-France High Seas Forecast listed on their website https://wwmiws.wmo.int ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of southern Senegal near 12.5N17W, and continues SW to near 11N25W. The ITCZ extends from 11N22W to 08N35W to 11N49W. Scattered moderate to isolated strong convection is from 06N to 10N between 25W and 35W. Similar convective activity is noted from 09N to 11N between 48W and 61W. The latter is just behind a surface trough that extends from 15N50W to 07N54W. ...GULF OF MEXICO... High pressure of 1017 mb centered over the NE Gulf near 28N85W dominates most of the basin producing mainly light to gentle anticyclonic flow and seas of 1 to 2 ft, with the exception of gentle to moderate southerly return flow and seas of 2 to 4 ft W of 94W. Narrow lines of low-level clouds are moving N over the western Gulf under the influence of the southerly flow. For the forecast, a cold front will skirt the far NE Gulf tonight. High pressure will build toward the region from the north in the wake of the front, leading to increasing E winds. Fresh to locally strong winds and building seas are expected Mon into Thu. ...CARIBBEAN SEA... Please read the SPECIAL FEATURES section for details about Hurricane Tammy and Invest AL95. A surface trough extends from the Cayman Islands to a 1008 mb low pressure centered near 11N81.5W. Numerous showers, with embedded thunderstorms are W of the through, more concentrated over the Cayman Islands. An outer rain band of Hurricane Tammy continues to impact the Lesser Antilles and the eastern Caribbean E of 65W. Outside of Tammy, gentle to moderate N to NE winds are W of the above mentioned trough, with light to gentle winds in the central and eastern Caribbean. Seas are generally 3 to 5 ft over the eastern Caribbean, and 2 to 4 ft elsewhere. For the forecast, Hurricane Tammy will continue to move away from the NE Caribbean. It will reach 20.1N 63.6W this evening, 21.4N 63.9W Mon morning, 22.3N 63.5W Mon evening, 23.0N 62.9W Tue morning, 23.6N 62.0W Tue evening, and 24.5N 61.0W Wed morning. Tammy will change little in intensity as it moves to near 27.5N 60.5W early Thu. A weak cold front will move into the northwest Caribbean later today, then stall from eastern Cuba to near Cozumel Island, Mexico Tue. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for details about Hurricane Tammy as well as gale conditions in the far eastern Atlantic. A cold front extends from 31N62W across the central Bahamas to the coast of central Cuba near 22N78W. A band of showers with isolated thunderstorms is related to the front. Gentle to moderate winds follow the front with seas of 6 to 8 ft based on a recent altimeter pass. In the tropical Atlantic, a surface trough extends 15N50W to 07N54W. An area of fresh winds persists near the northern end of the trough, particularly from 14N to 18N between 45W and 51W based on scatterometer data. Seas of 7 to 9 ft are noted within these winds. In the east Atlantic, a cold front extends from the coast of Western Sahara near 23N16W to 22N30W to 28N43W. A band of mainly low clouds and possible showers is associated with the front. Moderate northerly winds are observed in the wake of the front, increasing to fresh to strong between the Canary and the Madeira Islands. Seas behind the front increase rapidly due to swell generated from storm conditions to the north. Seas greater than 12 ft are currently reaching the Canary Islands. Seas of 8 to 12 ft dominate most of the waters N of 23N and E of 34W. For the forecast, Hurricane Tammy will move to 20.1N 63.6W this evening, 21.4N 63.9W Mon morning, 22.3N 63.5W Mon evening, 23.0N 62.9W Tue morning, 23.6N 62.0W Tue evening, and 24.5N 61.0W Wed morning. Tammy will change little in intensity as it moves to near 27.5N 60.5W early Thu. The aforementioned cold front will slide east and gradually dissipate into tonight. A second cold front will move off Florida tonight, then move eastward across the northern portions of the waters early this week. Looking ahead, high pressure building in the wake of the front combined with the impacts of Hurricane Tammy will bring an increase in winds and seas across the forecast area Mon night through Thu. $$ GR