000 AXNT20 KNHC 262329 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Sep 26 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 1800 UTC surface analysis and satellite imagery through 2220 UTC. ...SPECIAL FEATURES... Tropical Storm Philippe is centered near 17.1N 51.3W at 2100 UTC, or 780 nm E of the Northern Leeward Islands, moving W at 11 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are around 20 ft near just north of the center. Philippe continues to struggle due to strong west-southwesterly shear associated with a mid- to upper-level low to its northwest. The low-level center was completely exposed and void of deep convection most of the afternoon, However, convection has developed over and near the center in the past few hours. Scattered to numerous moderate to strong convection is now seen within 30 nm W and 320 nm E of the center. A westward to west-northwestward motion is expected during the next few days as well as gradual weakening. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center, at the website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml. The latest NHC Forecast/Advisory and Public Advisory can be read at www.hurricanes.gov for more details. Invest Area (AL91): Showers and thunderstorms continue to show signs of organization in association with a broad area of low pressure located several hundred miles west-southwest of the Cabo Verde Islands. A mean center of this area of low pressure was estimated near 11N39W. Scattered to numerous moderate to strong convection is seen from 08N to 15N between 39W and 44W. Environmental conditions are forecast to be conducive for development, and a tropical depression is expected to form in the next day or two while the system moves west- northwestward across the central tropical Atlantic. Seas 8 to 15 ft are occurring on the north and east side of the low pressure. There is a high chance of formation through 48 hours. In anticipation of this tropical development, a gale warning has been issued for Wed along the path of this system. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center, at the website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more information on the gale warning. ...TROPICAL WAVES... A western Caribbean tropical wave is near 83W from 19N southward. Upper-level diffluence is enhancing scattered strong convection from 11.5N to 23N between 81W and 89W. These strong clusters of thunderstorms are producing outflow boundaries containing very strong wind gusts which have increased seas to 4 to 7 ft across much of the western Caribbean. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic along the west coast of Africa near 15N17W then reaches southwestward to near 07N24W. The ITCZ begins at 07N24W to 08N31W and resumes at 06.5N45W to 08N54W. Scattered moderate isolated strong convection is noted from 06N to 09.5N between 21W and 27W. ...GULF OF MEXICO... A broad surface trough extends southward from the western Florida Panhandle to just offshore of the northwestern Yucatan peninsula. Scattered thunderstorms are occurring along and to the east of the trough axis, over the eastern Gulf, and the Yucatan Peninsula and Channel. Only isolated thunderstorms are noted to the west of the trough axis. Outside of convection, gentle to moderate SE to S winds and seas of 2 to 3 ft are noted across the eastern Gulf, east of the trough axis. Gentle to moderate NE to N winds with 2 to 3 ft seas prevail for the rest of the Gulf. For the forecast, the surface trough over the east-central Gulf will drift slowly into the western Gulf through mid week and dissipate. Scattered showers and thunderstorms are expected along and to the east of the trough, over the eastern half of the Gulf, through Wed night. Meanwhile, weak high pressure will persist over the north-central and northeast Gulf. This pattern will support gentle to moderate NE to E winds and slight seas across the basin through the middle of the week. Winds may increase over the northern Gulf the end of the week into the weekend as high pressure ridging strengthens over the southeastern United States. ...CARIBBEAN SEA... Strong thunderstorms over the NW Caribbean earlier this afternoon have diminished in intensity, while numerous strong convection is presently occurring near the coasts of Nicaragua and Honduras. Fresh SE winds are assumed to still prevail across the NW Caribbean with seas of 4 to 7 ft. Moderate to locally fresh easterly trades prevail across much of the basin between 65W and 80W, where seas are 4-7 ft. Otherwise, gentle to moderate NE winds and 3-5 ft prevail in the eastern Caribbean. For the forecast, strong thunderstorms over portions of the western Caribbean this evening will continue to generate fresh to locally strong winds, and are expected to gradually diminish tonight. High pressure north of the area will support moderate to fresh trade winds across most of the eastern and central Caribbean into mid week, with fresh to strong pulses off northwest Venezuela and northeast Colombia mainly during the overnight and early morning hours through Wed morning. Tropical Storm Philippe is expected to maintain a west-northwest motion for the next few days and pass north of the northern Leeward Islands Fri through Sat. ...ATLANTIC OCEAN... Refer to the SPECIAL FEATURES section above for details on Tropical Storm Philippe and Invest AL91. A 1020 mb high pressure is centered near 32N74W. Weak ridging in this area is producing winds gentle or weaker over the western Atlantic, except for moderate to locally fresh E-SE winds from Northeast Florida through the Bahamas to north of Hispaniola. West of 65W, seas are 5 ft or less in NE to E swell. Scattered thunderstorms are seen west of 76W. A surface trough extends from 31N61W to 24N66W with isolated showers near its axis. A high pressure ridge extends from 1022 mb high pressure near 36N18W to high pressure near 31N36W to a 1023 high pressure near 32N35W. Winds are moderate or weaker north of 23N across the E Atlantic with seas 6 to 7 ft in mixed swell. Over the tropical eastern and central Atlantic, Tropical Storm Philippe and Invest AL91 are causing strong winds and a large area of high seas from 06N to 24N between 32W and 58W. For the forecast west of 50W, Tropical Storm Philippe Philippe will move to 17.3N 52.7W Wed morning, 18.4N 54.5W Wed afternoon, 19.2N 56.1W Thu morning, 19.7N 57.9W Thu afternoon, weaken to a tropical depression near 20.0N 59.3W Fri morning, and 20.1N 61.0W Fri afternoon. Philippe will become a remnant low as it moves to near 20.2N 64.0W Sat afternoon. High seas in large E swell ahead of the storm have moved W of 55W, and will continue to spread W of 65W through the end of the week. Elsewhere, seas will build by Thu north of the Bahamas and east of Florida in NE swell. $$ Stripling