Atlantic Tropical Weather Discussion
138 AXNT20 KNHC 150950 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1215 UTC Tue Sep 15 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 0600 UTC surface analysis and satellite imagery through 0925 UTC. ...TROPICAL WAVES... A sharp tropical wave is along 55W, south of 21N, moving westward at 10-15 kt. Scattered moderate isolated strong convection is observed from 10N to 21N and between 47W and 57W. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic along the coast of Guinea near 11N15W and continues to 08N36W. The ITCZ extends from 08N37W to 11N54W. Scattered moderate to isolated strong convection is noted from 04N to 17N and east of 25W. ...GULF OF AMERICA... A few showers and isolated thunderstorms are occurring in the eastern Gulf waters and off Veracruz. A weak high pressure over the NE Gulf supports moderate to fresh SE-E winds and moderate seas in the Bay of Campeche and in the western Gulf, west of 95W. Elsewhere, light to gentle winds and slight seas prevail. For the forecast, a strong high pressure over the eastern United States will build southward behind a weakening cold front that will spread across the eastern Gulf waters. The tighter pressure gradient will support fresh to locally strong NE-E winds and rough seas starting in the NE Gulf tonight and spreading over the northern Gulf waters through Thu night. Elsewhere, a diurnal trough will move westward offshore the Yucatan Peninsula each evening through Thu night, bringing nightly pulses of fresh to locally strong NE winds. Conditions will improve across the basin Fri, allowing for moderate or weaker winds and slight to moderate seas during the weekend. ...CARIBBEAN SEA... The interaction between an large upper-level low pressure system over the north-central Caribbean and tropical moisture support numerous showers and thunderstorms over the SW Caribbean. This environment is also generating a few showers in the eastern Caribbean, bringing some rain to Puerto Rico and the Virgin Islands. High pressure north of the area sustains fresh to near gale-force easterly trade winds and moderate to rough seas across much of the central Caribbean. Moderate to fresh NE-E winds and moderate seas are occurring in the eastern Caribbean, Windward Passage and lee of Cuba. Elsewhere, moderate or weaker winds and moderate seas prevail. For the forecast, tight pressure gradient between the subtropical ridge located north of the islands and lower pressures in Colombia will support fresh to locally near gale-force easterly trade winds and moderate to rough seas across much of the central Caribbean, with moderate to fresh trades elsewhere from 11N to 18N. These conditions will persist through the workweek. Elsewhere, moderate or lighter winds and slight to moderate seas are expected, except moderate to fresh mainly in the evenings near the Windward Passage and Lee of Cuba through midweek. Winds may diminish across the basin by the end of the week into the upcoming weekend as the pressures gradient relaxes, with seas also slightly subsiding. ...ATLANTIC OCEAN... A pre-frontal trough is noted ahead of an approaching cold front to the NW waters producing scattered showers and isolated thunderstorms north of 28N and between 67W and 75W. Meanwhile, a large upper-level low over and east of the SE Bahamas is supporting scattered showers south of 25N and between 61W and 75W. High pressure dominates the rest of the SW North Atlantic, sustaining moderate or weaker winds and slight to moderate. Another upper-level low over the central Atlantic interacts with a surface trough analyzed along 51W and north of 24N, producing numerous showers and isolated thunderstorms north of 26N and between 45W and 61W. Environmental conditions are forecast to become more conducive for development in a few days, and a tropical depression could form late this week as the system moves slowly west-northwestward over the subtropical Atlantic. The system has a medium chance of formation over the next 7 days. A strong subtropical ridge centered north of the Azores extends southward into the central and eastern Atlantic, supporting moderate to fresh easterly winds and moderate seas between 30W and 60W. Moderate or weaker winds and moderate seas are prevalent elsewhere. For the forecast west of 55W, a cold front is approaching the waters off NE Florida and then will become stationary from Bermuda to the NW Bahamas into Wed. A tight pressure gradient between the building ridge over the eastern United States and the front will result in fresh to locally strong NE winds and seas to build to rough N of the Bahamas and W of 70W through early Thu. Conditions will improve later Thu into Fri. During the middle to later portion of the week, a trough of low pressure is forecast to move west- northwestward into the NE portion of the waters, bringing thunderstorms while also weakening the high and pressure gradient.