Tropical Weather Discussion

Full Alert Message

Tropical Weather Discussion NWS National Hurricane Center Miami FL 0015 UTC Wed Mar 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ...SPECIAL FEATURES... East Atlantic Long-period N Swell: Large, long-period N swell generated by a large fetch of gale to storm-force winds in the northeast Atlantic will continue to propagate southward of 31N through Wed. Expect seas of 12 and 18 ft from 25N to 31N between 30W and 45W tonight. These very rough seas will shift farther southward to near 23N Wed morning, and then become reinforced with additional large N swell Wed through Thu. Seas across these northeastern waters will remain 12 ft and greater through at least Fri night. Please refer to the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... Then monsoon trough enters the Atlantic near the coast of Guinea near 10N14W, then curves southwestward to 03N20W. An ITCZ continues from 02N24W to 02S43W. Scattered moderate to strong convection is noted from 03N to 06N between 10W and 17W. Scattered moderate isolated strong convection is noted south of 04N between 17W and 43W. ...GULF OF AMERICA... The cold front has cleared the basin this afternoon, taking convection with it. In its wake, 1029 mb high pressure centered over eastern Texas is building into the Gulf. Fresh to strong NE winds dominate the SE half of the basin, with winds diminishing to gentle to moderate to the NW. Seas are rough where the winds are fresh to strong, with some very rough seas to 13 ft in the Bay of Campeche and in the Yucatan Channel. Elsewhere, moderate seas exist. For the forecast, winds will continue to diminish, and seas will continue to subside from north to south through this afternoon and evening, except for the Yucatan Channel, where fresh to strong N to NE winds will linger until Wed morning. In the wake of the front on Wed, high pressure will build across the region and prevail into the weekend. ...CARIBBEAN SEA... A cold front has entered the Yucatan Channel, with scattered moderate convection along and within 90 nm south of it. Scattered moderate convection is also noted along and east of a surface trough that extends southward from central Cuba through the Cayman Islands. The association thunderstorms continue eastward to waters near Jamaica. N of the cold front, strong to near gale- force NE winds and rapidly building rough seas exist. Elsewhere across the NW and SW basin, winds are moderate or weaker and seas are moderate. Across the central basin, fresh to strong winds and seas of 8 to 11 ft prevail, with fresh winds and moderate seas farther east. For the forecast, a broad surface ridge extending southwestward from the north Atlantic to near the central Bahamas and the NE Caribbean is supporting fresh to strong trade winds and rough seas across the waters near the Lesser Antilles, and the eastern and central Caribbean, including the Atlantic exposures and Passages through Wed. The cold front will slow down and possibly stall from western Cuba to the Gulf of Honduras by early Wed morning while dissipating. This should decrease the influence from the ridge and allow winds and seas across the central and eastern Caribbean to gradually subside through Sat. ...ATLANTIC OCEAN... A cold front extends from 31N73W to the Central Bahamas to Florida Straits. A band of numerous moderate to isolated strong convection exists ahead of it, along a pre-frontral trough drapped from 31N71W to the SE Bahamas. Behind the front, moderate to fresh N winds and moderate to locally rough seas prevail. E of the front, an expansive surface trough dominates the basin, anchored by a 1041 mb high pressure at 41N47W. These is leading to widespread fresh to locally strong NE to E winds, with moderate to rough seas. A weakening cold front over the eastern waters is noted from 31N21W to 26N48W. Strong N winds and very rough seas are N of this boundary. For the forecast west of 55W, by Wed afternoon, the front will stall from near Bermuda to the central Bahamas. At the same time, a weak low pressure system may develop along the stationary front, tightening the pressure gradient and supporting fresh to strong winds with rough to very rough seas through the rest of the week as this system moves eastward.