Atlantic Tropical Weather Discussion
898 AXNT20 KNHC 171641 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1815 UTC Thu Sep 17 2026 Tropical Weather Discussion for North America, Central America Gulf of America, 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 1640 UTC. ...TROPICAL WAVES... The tropical wave over the central Atlantic has been repositioned based on satellite imagery and tropical wave diagnostics. The wave axis is near 34W, south of 16.5N. Scattered moderate convection is noted from 10N to 17N between 30W and 39W. A tropical wave in the E Caribbean has been repositioned based on satellite imagery and tropical wave diagnostics. The wave axis is near 70W, south of 22N. Scattered moderate convection is noted from 17N to 22N between 68W and the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 18N16W and extends southwestward to 09N47W. The ITCZ extends from 09N47W to 10N59W. Aside from convection noted in the tropical waves section above, scattered moderate convection is noted from 06N to 11N west of 20W. Similar convection is depicted from 07N to 11N between 45W and 49W. ...GULF OF AMERICA... Scattered moderate convection is depicted west of 91W in association to a surface trough over the area. Another trough extends from the western Atlantic to south Florida to 24N86W. Scattered moderate convection is also present along this trough. The pressure gradient between a 1027 mb high pressure over the SE of the United States and the aforementioned surface trough over the SE Gulf supports fresh NE to E winds and moderate seas over the NE and north- central Gulf. Elsewhere, moderate or weaker winds, and slight seas, are noted. For the forecast, the aforementioned pressure gradient will spread westward over the remainder of the northern Gulf waters through tonight before improving Fri into Sat. Meanwhile, a rather broad upper- level low will move towards Florida from the western Atlantic today through Fri. This feature will lead to increasing shower and thunderstorm activity over the eastern and central Gulf waters. ...CARIBBEAN SEA... An upper level trough is supporting scattered showers and isolated thunderstorms over the NW Caribbean. While, a mid-level trough is supporting numerous showers west of 81.5W. Please read the Tropical Wave section above for additional convection across the basin. The pressure gradient between ridging north of the area along with lower pressure over Colombia- Venezuela is supporting fresh to strong trades over the S central Caribbean. Seas 6 to 8 ft are over these waters. Moderate to fresh winds, and moderate seas, are elsewhere east of 84W. West of 84W, gentle to moderate winds and seas 2 to 4 ft prevail. For the forecast, the aforementioned pressure gradient will generally maintain fresh to strong trades along with moderate to locally rough seas over most of the central Caribbean through the end of the week. Otherwise, moderate to fresh trades and moderate seas will continue across the eastern Caribbean through the weekend while light to gentle winds and slight to moderate seas will dominate the NW part of the basin. A tropical wave is entering the central Caribbean, and will reach the western Caribbean over the weekend. Scattered showers and thunderstorms will accompany the passage of the wave. ...ATLANTIC OCEAN... A stationary front extends from near Bermuda west-southwestward to Ocean Reef, Florida. Moderate to fresh NE winds and seas 5 to 6 ft prevail N of the front. Scattered moderate convection is noted north of 23N and west of 66W in association to this frontal boundary. Light to gentle winds, and slight seas, are SE of the front N of 23N and W of 55W. An upper level trough that extends from north of Puerto Rico and the U.S. Virgin Islands to around 31N is supporting scattered moderate convection south of 24N between 56W and 70W and north of 26N between 40W and 59W. Additional convection in the basin is described in the Tropical Waves and Monsoon Trough/ITCZ sections above. Fresh to locally strong NE winds, and moderate seas, are noted near the Canary Islands, extending SW to near 30W. Elsewhere, gentle to moderate winds and moderate seas prevail. For the forecast west of 55W, the pressure gradient between high pressure over the southeastern U.S. and a stationary front that extends from near Bermuda to the NW Bahamas will maintain moderate to fresh NE winds and moderate seas west of the front through today. Conditions will improve late today into Fri as high pressure becomes the dominant feature across the basin into the weekend. Meanwhile, a broad upper-level low located east of Florida in combination with a very moist and unstable environment will continue to support scattered to numerous showers and thunderstorms over most of the forecast waters the next few days as it moves toward Florida on Fri.