Atlantic Tropical Weather Discussion
934 AXNT20 KNHC 180435 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Fri Sep 18 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 0430 UTC. ...TROPICAL WAVES... A central Atlantic tropical wave has its axis along 36W from 03N to 18N, moving westward near 15 kt. Scattered moderate convection is from 08N to 15N between 31W and 42W. A central Caribbean tropical wave has its axis along 72W, moving westward at 10 to 15 kt. Scattered moderate convection is noted along the wave axis and N of 17N. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 18N16W and continues southwestward to 10N39W, where it transitions to the ITCZ to 07N58W. Aside from convection associated to the tropical waves as described above, scattered moderate convection is evident from 09N to 12N between 47W and 51W. ...GULF OF AMERICA... A trough is analyzed from just west of the Bahamas, southwestward across extreme South Florida and to just north of the Florida Keys, reaching to near 24N86W. A western Gulf trough extends from 25N96W to 24N97W and to 19N94W. Scattered moderate convection is noted along both troughs. The pressure gradient between high pressure over the southeastern U.S. and a weakening frontal 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, fresh NE to E winds and moderate seas over the NE and north-central Gulf 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 on Fri, and into the NE Gulf on Sat. This feature will lead to increasing shower and thunderstorm activity over Florida, and then over the eastern and central Gulf waters. Fairly tranquil marine conditions are forecast by the end of the weekend into early next week. ...CARIBBEAN SEA... The pressure gradient between weakening high pressure over the western Atlantic and relatively lower pressure in northern South America is allowing for fresh to strong trades over the south- central Caribbean. Seas in the range of 6 to 8 ft are over these waters. Moderate to fresh trades along with moderate seas are elsewhere E of 82W while gentle to moderate trades and seas of 2 to 4 ft are W of 82W, except for higher seas of 4 to 5 ft south of 17N as noted in a satellite scatterometer data pass. Upper-level divergence east of an upper-level low that is over the northern Yucatan Peninsula is supporting scattered showers and isolated thunderstorms over the northwestern Caribbean. An upper-level disturbance riding along a jet stream branch is keeping active weather in the form of numerous moderate convection over the waters from 11N to 17N west of 80W to inland (near 85W) of Honduras and Nicaragua. Scattered moderate convection is over the interior of Honduras. 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 Fri night. Winds will diminish to moderate to fresh speeds over the upcoming weekend into early next week as the pressure gradient relaxes across the area. Moderate or weaker winds and slight to moderate seas are forecast elsewhere. ...ATLANTIC OCEAN... A stationary front extends from near 31N68W southwestward to 27N75W and to extreme South Florida. Moderate to fresh northeast winds and seas 5 to 6 ft are north of of the front. Scattered moderate convection is seen north of about 23N and west of 66W in association to this frontal boundary. Light to gentle winds and slight seas are southeast of the front north of 23N and west of 55W. A surface trough is analyzed along 48W and N of 23N. Scattered moderate convection is noted along the trough and in its vicinity mainly N of 26N between 43W-51W. 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 north of 24N and W of 60W. To the east, fresh to strong north to northeast winds and moderate seas per latest scatterometer data passes are near the Canary Islands. They extend westward to near 30W. Elsewhere, gentle to moderate winds and moderate seas prevail. For the forecast west of 55W, the pressure gradient over the W Atlantic will maintain moderate to fresh NE winds and moderate seas west of the front through tonight. Conditions will improve early on Fri as high pressure becomes the dominant feature across the basin into the weekend into early next week. Meanwhile, abundant tropical moisture, combined with an upper-level low located east of Florida, will continue to support scattered to numerous showers and thunderstorms, mainly W of 70W, through at least Sun.