000 AXNT20 KNHC 270606 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Wed Sep 27 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 0500 UTC. ...SPECIAL FEATURES... Tropical Storm Philippe is centered near 17.4N 52.0W at 28/0300 UTC, or 635 nm E of the Northern Leeward Islands, and moving W at 10 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained winds are 40 kt with gusts to 50 kt. Peak seas are 20 to 21 ft near and just northeast of the center. Scattered to numerous moderate convection with isolated strong convection is seen near, and to the north and southeast of the center from 13N to 20N between 46W and 52W. Philippe continues to struggle due to strong southwesterly shear associated with an upper-level trough to its north. A westward to west-northwestward motion and a gradual weakening trend are expected during the next few days. 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. Gale Warning Associated with Invest Area (AL91): A central Atlantic tropical wave is near 41W from 17N southward through a 1008 mb low (AL91) at 11N41W, and moving west at 15 to 20 kt. Scattered moderate to isolated strong convection is seen from 07N to 16N between 36W and 44W. A large area of fresh to locally strong E to SE winds with 7 to 10 ft seas are present from 10N to 19N between 35W and 42W. These winds are expected to become gale force near 13N43W on Wednesday. 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. AL91 is about half way between the Cabo Verde Islands and Lesser Antilles. Environmental conditions are forecast to be conducive for development, and a tropical depression or storm is expected to form in the next day or so while the system moves west- northwestward across the central tropical Atlantic. Please read the latest Tropical Weather Outlook issued by the National Hurricane Center, at the website https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 for more information ...TROPICAL WAVES... A western Caribbean tropical wave is near 84W from 19N southward across Honduras, Nicaragua and Costa Rica into the East Pacific. It is moving west at 10 kt. Aided by mid-level diffluent flow, scattered showers and thunderstorms are occurring from 15N to 20N between 81W and 84W. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic along the Mauritania coast just south of Nouakchott, and curves southwestward to 09N20W. An ITCZ continues from 09N20W to 07N32W. Scattered moderate isolated strong convection is noted from 06N to 09.5N between 21W and 27W. Widely scattered moderate convection is found near and up to 160 nm northwest of the monsoon trough. Similar convection is present near and up to 180 nm north of the ITCZ. ...GULF OF MEXICO... A broad surface trough extends southwestward from the western Florida Panhandle to the eastern Bay of Campeche. Isolated thunderstorms are occurring across the central Gulf. Another surface trough runs southwestward from northeastern Florida to the Florida Keys. Widely scattered showers and isolated thunderstorms are evident from the Yucatan Channel northeastward to the northeastern Gulf. Moderate SE winds and seas of 2 to 4 ft are noted at the southeastern Gulf, including the Yucatan Channel and Straits of Florida. Gentle to moderate E to SE winds and 1 to 2 ft seas prevail for the rest of the Gulf. For the forecast, the broad surface trough will drift slowly westward through Wed night before dissipating. Unsettled weather will persist across the eastern half of the Gulf through Wed night. Meanwhile, gentle to moderate NE to E winds and slight seas will prevail across the basin through early Thu. Winds may increase over the northern Gulf by Friday as high pressure ridging strengthens over the southeastern United States. ...CARIBBEAN SEA... Convergent easterly trades are coupling with strong upper-level divergent flow to trigger scattered showers and isolated thunderstorms near Haiti and southeastern Cuba. Farther east, isolated thunderstorms are noted near the Lesser Antilles. Strong thunderstorms related to a tropical wave are producing locally fresh to strong winds and 5 to 7 ft seas from the Gulf of Honduras to near the Cayman Islands. Moderate ENE to E winds and seas at 5 to 7 ft dominate the central basin. Light to gentle monsoonal winds and seas of 2 to 4 ft exist near Costa Rica and Panama. Gentle to moderate ENE to SE winds and 3 to 5 ft seas prevail elsewhere in the basin. For the forecast, seas have started to build across the waters east of the Leeward Islands ahead of Tropical Storm Philippe well to the east. Strong thunderstorms mentioned above are forecast to gradually diminish later tonight. High pressure north of the area will support moderate to fresh trade winds across most of the eastern and central basin into midweek, with fresh to strong pulses off northwest Venezuela and northeast Colombia mainly during the overnight and early morning hours through Wed morning. ...ATLANTIC OCEAN... Refer to the SPECIAL FEATURES section above for details on Tropical Storm Philippe and a Gale Warning related to Invest AL91. Convergent southeasterly winds to the east of a surface trough over Florida are triggering widely scattered showers and isolated thunderstorms from the northwest Bahamas northward to beyond 31N. Refer to the Monsoon Trough/ITCZ section for additional weather in the Atlantic Basin. The Atlantic Ridge associated with both the Bermuda and Azores Highs is supporting light to gentle winds and 3 to 6 ft seas in moderate northerly to easterly swell north of 25N between 30W and the Georgia-Florida coast. Near the Canary Islands, gentle to moderate with locally fresh NNE to NE trades and seas of 6 to 8 ft are present north of 18N between the northwest Africa coast and 30W. Fresh to strong with locally near-gale easterly winds and seas of 10 to 14 in mixed swells are seen from 20N to 25N between 45W and 54W. Otherwise, gentle to moderate with locally fresh ENE to E winds and 6 to 8 ft seas in large northerly swell are evident from 20N to 25N between 30W and 60W. Farther west, gentle to moderate ENE to ESE winds and 3 to 6 ft seas are found from 20N to 25N between 60W and the Bahamas. Outside the direct impact from Philippe and AL91, including the Gale Warning, gentle to moderate NE to SSE winds and seas of 3 to 6 ft in moderate northerly swell are present from 10N to 18N/20N between the central Africa coast and 55W. Farther west, gentle to moderate ENE to SE to SW winds and seas at 6 to 9 ft in large easterly swell exist from 10N to 20N between 55W and the Lesser Antilles. Light to gentle monsoonal and southerly winds and 5 to 7 ft seas in mixed swells prevail for the remainder of the Atlantic Basin. For the forecast west of 50W, Tropical Storm Philippe will move to 17.3N 52.7W Wed morning, 18.4N 54.5W Wed afternoon, 19.2N 56.1W Thu morning. It will then reach near 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. Rough seas ahead of the storm have moved W of 55W, and will continue to spread east of 65W through the end of the week. Elsewhere, seas may build by Thu north of the Bahamas and east of Florida in NE swell. $$ Forecaster Chan