Atlantic Tropical Weather Discussion
670 AXNT20 KNHC 190536 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Sat Sep 19 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 0000 UTC surface analysis and satellite imagery through 0140 UTC. ...TROPICAL WAVES... A central Atlantic tropical wave has its axis along 43.5W from 06N to 21N, moving westward around 10 kt. Scattered moderate isolated strong convection is noted from 12N to 19N between 38W and 44W. A western Caribbean tropical wave has its axis roughly along 82W south of 19N near the Cayman Islands to near the border of Costa Rica and Panama, moving westward around 20 kt. Scattered moderate to isolated strong convection is from 13N to 20N between 77W and 85W. Additional deep convection is present to the south along the intersection of the wave and the eastern Pacific monsoon trough, across the coastal waters and inland portions of Costa Rica and Panama. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the Atlantic along the coast of Senegal near 14N16W and continues southwestward to 11N26W then northwestward to 14N42W. The ITCZ extends from 13N45W to 1009 mb low pressure seen by a very recent ASCAT scatterometer pass at 13N51W to along the NE coast of Venezuela at 10N65W. A surface trough is analyzed south of the monsoon trough from 12N18W to 07N39W. Aside from convection associated to the tropical wave described above, isolated to widely scattered moderate to strong convection is seen on conventional satellite imagery within 180 nm either side of the surface trough. Scattered moderate to strong convection is near the surface low, from 12N to 15N between 48W and 53W. ...GULF OF AMERICA... A few surface troughs are analyzed and impacting the Gulf. One extends across Central Florida to west of Tampa Bay, and another to the south from 25N84W to 25N95W. Isolated to widely scattered showers and thunderstorms are near both troughs. Moderate to locally fresh winds are north of the 25N trough and west of 85W, along with 3-6 ft seas. Gentle to moderate winds and 1-3 ft seas prevail elsewhere. Meanwhile, the diurnal surface trough is over the western Yucatan Peninsula with convection present over the peninsula. For the forecast, a ridge will dominate the Gulf region supporting gentle to moderate winds and slight to moderate seas through Sun. Winds will then ease to light to gentle speeds early next week, with seas remaining slight. Meanwhile, a broad upper- level low currently located over northeastern Florida will move into the NE Gulf on Sat. This feature will lead to increasing shower and thunderstorm activity over the eastern and central Gulf waters. ...CARIBBEAN SEA... Please refer to the tropical wave section for details on a wave in the western Caribbean including associated convection. The pressure gradient between broad high pressure north of the basin and relatively lower pressure in northern South America is allowing for fresh to strong trades over the central Caribbean from 11N to 17N between 66W and 77W, where seas are 6-9 ft. Moderate to fresh trades are found elsewhere from 11N to 18N between 64W and 80W, along with seas of 4-7 ft. Gentle to moderate winds, and seas of 3-5 ft remain across the remainder of the basin, except for 1-3 ft seas in the NW Caribbean. For the forecast, the pressure gradient between high pressure over the western Atlantic and the Colombian Low will generally maintain fresh to strong trades along with moderate to locally rough seas over most of the central Caribbean through early Sat morning. Winds will diminish to moderate to fresh speeds thereafter as the pressure gradient relaxes across the area. Moderate or weaker winds and slight to moderate seas are forecast elsewhere. ...ATLANTIC OCEAN... Please refer to the tropical wave section for details on a wave in the central Atlantic including associated convection, as well as convection near the monsoon trough/ITCZ and nearby features. The remnants of a stationary front as a frontal trough extend from 31N74W to near Cape Canaveral, Florida. Some isolated to widely scattered showers are near the trough. South of the trough, upper- level disturbances riding along a jet stream branch from across the northwest Caribbean to the Bahamas are supporting scattered moderate convection from 18N to 28N between 61W and 77W. Another surface trough is in the central Atlantic, from 31N43W to 23N57W as seen by recent ASCAT scatterometer data. Scattered moderate convection is noted within 120 nm either side of the trough. A relatively weak pressure gradient is the result of the above features across the basin resulting in winds of moderate or weaker. Moderate to fresh localized winds are over the SE Bahamas and Turks and Caicos with similar winds near the NE coast of South America, and north of 17N between Africa and 23W where the normally locally tight pressure gradient exists. Seas of 3-4 ft in mainly long period SE swell dominates the waters west of 55W across the offshore waters zones. Similar seas are found north of 23N between 30W and 55W in mainly NE swell. Seas are 5-7 ft from 13N to 20N between Africa and the Cabo Verde Islands, with similar heights north of 27N between Africa and 23W, and 3-5 ft in mixed NE and SE swells across the remainder of the waters. For the forecast west of 55W, a frontal trough extending from near 31N74W to Cape Canaveral, Florida will dissipate overnight. High pressure will become the dominant feature across the basin during the weekend into early next week, promoting light to gentle winds with slight to moderate seas, with the exception of moderate to locally fresh E to SE winds and moderate seas offshore Hispaniola. Meanwhile, abundant tropical moisture, combined with an upper- level low now located over NE Florida, will continue to support scattered to numerous showers and thunderstorms, across the central and southern Bahamas, and between the central Bahamas and Bermuda, through at least Sun.