000 AXNT20 KNHC 251024 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Mon Sep 25 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 0600 UTC surface analysis and satellite imagery through 1010 UTC. ...SPECIAL FEATURES... Tropical Storm Philippe is centered near 17.4N 43.9W at 25/0900 UTC or 1150 nm W of the Cabo Verde Islands, moving WNW at 9 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas near the center are up to 20 ft. Numerous moderate scattered strong convection is noted within 210 nm in the southeast semicircle of the low and within 90 nm in the northwest semicircle. A continued west- northwest motion is expected for the next day or two, with a gradual turn to the northwest anticipated by mid- week. Little overall change in strength is forecast during the next 2 to 3 days. Please, read the latest HIGH SEAS FORECAST, that is issued by the National Hurricane Center, at the website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Tropical Storm Philippe NHC Forecast/Advisory and Public Advisory, at www.hurricanes.gov, for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave (Invest 91L) has its axis along 29W, south of 19N, moving westward at 10 kt. A 1010 mb low pressure is along the wave axis near 09N29W where it intersects the monsoon trough. Scattered moderate to isolated strong convection is observed within 120 nm of the low pressure. Environmental conditions are forecast to be conducive for additional development, and a tropical depression is likely to form around mid-week as the system moves west- northwestward across the central tropical Atlantic. The disturbance has a low chance of development over the next 48 hours. For more information, please read the Tropical Weather Outlook at hurricanes.gov A central Caribbean tropical wave has its axis along 74W, south of 21N, moving westward at 10-15 kt. No deep convection is noted near the trough axis. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic through the coast of Mauritania near 17N16W and continues southwestward to a 1010 mb low pressure (AL91) near 09N29W and then to 06N35W. The ITCZ extends from 06N35W to 08N42W, and from 12N48W to 09N58W. Scattered moderate convection is present within 120 nm on both sides of the ITCZ between 48W and 55W. ...GULF OF MEXICO... A broad surface trough extends from west-central Florida to the central Yucatan peninsula. Abundant tropical moisture and divergence aloft is enhancing the development of scattered showers and thunderstorms across the SE Gulf, especially over and just north of the Yucatan Channel. Fairly tranquil weather conditions are found elsewhere in the basin. The weak pressure gradient across the Gulf supports gentle to moderate winds and slight seas. For the forecast, the surface trough over the southeast and south- central Gulf accompanied by scattered showers and thunderstorms will drift slowly into the western Gulf through mid week and dissipate. 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. ...CARIBBEAN SEA... Abundant tropical moisture and a favorable upper level pattern continue to sustain scattered moderate to isolated strong convection north of 15N between 75W and 85W. Scattered showers are also noted in the eastern Atlantic, affecting the Windward Islands. Isolated showers dot the remainder of the Caribbean Sea. A building subtropical ridge over the central Atlantic and lower pressures in northern South America support fresh to strong easterly trade winds in the central Caribbean. An earlier scatterometer satellite pass captured the strongest winds occurring off northern Colombia. Seas in these waters are 5-8 ft. Moderate to fresh easterly breezes are found in the eastern Caribbean Sea, along with seas of 3-6 ft. Elsewhere, light to gentle winds and slight seas prevail. For the forecast, high pressure north of the area will continue to 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 during mainly the overnight and early morning hours. Seas will build in mixed NE and E swell across the waters east of the Leeward Islands starting late Tue, ahead of Tropical Storm Philippe. Philippe is expected to turn NW before reaching 55W, and move into the central Atlantic. ...ATLANTIC OCEAN... Refer to the Special Features section for details on Tropical Storm Philippe. Upper level divergence is supporting scattered showers and a few thunderstorms from central Cuba across the eastern Straits of Florida to the northern Bahamas. Farther east, a surface trough between Bermuda and Hispaniola and divergence aloft continue to produce isolated to scattered moderate convection, especially north of 25N and between 60W and 65W. A surface trough reaches from 30N31W to 27N50W, south of a broad ridge centered on 1023 mb high pressure near 35N45W. Fresh to strong E winds and locally rough seas to 8 ft are noted near the 1010 mb low pressure at 09N29W. Elsewhere, outside of the area impacted by Philippe, the pattern is supporting generally moderate trade winds across the basin. Various altimeter pass over the past several hours confirm mostly 5 to 7 ft combined seas across the basin. For the forecast west of 55W, Tropical Storm Philippe is well east of the area near 17.4N 43.9W at 5 AM EDT, and is moving west-northwest at 9 kt. Maximum sustained winds are 45 kt with gusts to 55 kt, and the minimum central pressure is 1000 mb. Philippe will continue to move west- northwest for the next day or two, with a gradual turn to the northwest anticipated by mid- week. Looking ahead, this path will place the center of the storm near 21.2N 53.3W Wed afternoon, 22.4N 54.5W Thu morning and 24.0N 56.0W Fri. Regardless of the exact position of the center later in the week, rough seas ahead of the storm can be expected east of 60W starting late Tue. Elsewhere, seas may build by Thu north of the Bahamas and east of Florida in NE swell. $$ Christensen