000 AXNT20 KNHC 261739 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... Tropical Storm Philippe is centered near 17.3N 50.3W at 26/1500 UTC or 730 nm E of the Northern Leeward Islands, moving W at 12 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are around 22 ft near and just northwest 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 is completely exposed and deep convection remains well removed to the east of the center. Scattered moderate to isolated strong convection is seen within 485 nm of the center in the E semicircle. 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. 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 9 ft are depicted mainly on the north and east side of the low pressure. There is a high chance of formation through 48 hours. ...TROPICAL WAVES... A western Caribbean tropical wave is near 82W from 19N southward. Upper-level diffluence is enhancing scattered strong convection from 10N to 22N between 79W and 85W. These strong clusters of thunderstorms are producing outflow boundaries containing very strong wind gusts which have increased seas to 4 to 6 ft across much of the western Caribbean. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic along the west coast of Africa near 12N17W then reaches southwestward to near 07N21W. The ITCZ begins at 07N22W to 08N29W and resumes at 06N45W to 07N54W. No significant convection is depicted in association with the TROUGH/ITCZ. ...GULF OF MEXICO... A broad surface trough extends southward from the western Florida Panhandle to the western Yucatan peninsula. Scattered thunderstorms are occurring along and to the east of the trough axis, over the eastern Gulf. 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 NE to moderate winds with 2 to 3 ft seas prevail for the rest of the Gulf. For the forecast, a 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 Gulf have been inducing areas of strong winds and seas of 8 to 9 ft over portions of the western Caribbean during the past hours. Otherwise, fresh trades prevail over the central Caribbean, locally strong near the coasts of Colombia and Venezuela. Seas are 5-8 ft across the central basin and 3-5 ft in the eastern Caribbean. For the forecast, strong thunderstorms over portions of the western Caribbean overnight have generated locally strong winds and seas of 8 to 9 ft, that are forecast to gradually subside later today. 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. Seas will build in mixed NE and E swell across the waters east of the Leeward Islands starting late today, ahead of Tropical Storm Philippe. ...ATLANTIC OCEAN... Refer to the SPECIAL FEATURES section above for details on Tropical Storm Philippe and Invest AL91. A 1019 mb high pressure is centered near 32N73W. Ridging in this area is producing winds gentle or weaker over the western Atlantic, except for moderate to locally fresh E-SE winds from Central Florida through the Bahamas to north of Hispaniola. West of 65W, seas are 5 ft or less. Scattered showers and thunderstorms are seen mainly west of 74W. A surface trough extends from 31N63W to 24N66W with isolated showers east of its axis. A high pressure ridge extends from 1022 mb high pressure near 36N18W to high pressure near 32N36W to a 1023 high pressure near 32N35W. Winds are moderate or weaker north of 25N 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 rough seas from 08N to 21N between 33W and 52W. For the forecast west of 50W, Tropical Storm Philippe is near 17.3N 50.3W at 11 AM EDT, and is moving west at 12 kt. Maximum sustained winds are 40 kt with gusts to 50 kt, and the minimum central pressure is 1003 mb. Philippe will move to 17.9N 51.6W this evening, 18.9N 53.4W Wed morning, 19.8N 55.0W Wed evening, 20.7N 56.5W Thu morning, 21.2N 58.0W Thu evening, and weaken to a tropical depression near 21.2N 59.8W Fri morning. Philippe will become a remnant low as it moves to near 21.2N 62.6W early Sat. Rough seas ahead of the storm can be expected east of 60W starting late today. Elsewhere, seas may build by Thu north of the Bahamas and east of Florida in NE swell. $$ KRV