{"msg": "397\nAXNT20 KNHC 181640\nTWDAT \nTropical Weather Discussion\nNWS National Hurricane Center Miami FL\n1815 UTC Fri Sep 18 2026\nTropical Weather Discussion for North America, Central America\nGulf of America, Caribbean Sea, northern sections of South\nAmerica, and Atlantic Ocean to the African coast from the\nEquator to 31N. The following information is based on satellite\nimagery, weather observations, radar and meteorological analysis.\nBased on 1200 UTC surface analysis and satellite imagery through \n1600 UTC.\n...TROPICAL WAVES...\nA central Atlantic tropical wave has its axis along 40W, S of 21N,\nmoving westward 10 to 15 kt. Scattered moderate isolated strong \nconvection is from 08N to 16N between 35W and 44W. A cluster of \nstrong convection is occurring along the N end of the wave, from\n21N to 23.5N between 41W and 44W.\nA central Caribbean tropical wave has its axis along 77W-78W, S of\n19N to eastern Panama, moving westward at around 15 kt. Isolated \nmoderate convection is noted S and W of Jamaica, while numerous\nstrong convection is noted along the intersection of the wave and\nthe eastern Pacific monsoon trough, across the coastal waters of\nPanama and Colombia. \n...MONSOON TROUGH/ITCZ...\nThe monsoon trough enters the Atlantic along the coast of Senegal \nnear 14N17W and continues southwestward to 09N22W to 13N34W to\n13N44W. The ITCZ extends from 11N44W to 12.5N50W, then resumes\nfrom 11N53W to 10.5N61W. Aside from convection associated to the \ntropical waves as described above, scattered moderate isolated \nstrong convection is noted from 06N to 12.5N between the coast of\nAfrica and 34W. A small 1014 mb low about the ITCZ near 12N50.5W \nis producing scattered moderate convection within 120 nm across\nthe N semicircle of the low. \n...GULF OF AMERICA...\nThe old frontal trough extending from the Atlantic near the NW \nBahamas and across portions of S Florida and into the SE Gulf is\nno longer clearly identifiable. However, associated low level\nmoisture persists across the southern Gulf S of 26N between\nFlorida and Mexico. Scattered moderate isolated strong convection\nis occurring within this band of moisture from 22N to 26N between\nthe Straits of Florida and 94.5W. At the surface, a broad high\npressure ridge extends across the southeastern U.S. along about\n34N, and is promoting gentle to moderate easterly winds across the\nbasin N of 25N, where seas are 4 to 7 ft. A surface trough is\nalong 89-90W from 23N to 26.5N and is aiding in focusing\nconvection to its east, and promoting the strongest winds and seas\nacross the basin across the northern end of the trough. Light to\ngentle mostly easterly winds prevail S of 25N, where seas are 2-4\nft. A weak thermal surface trough is over the eastern Bay of \nCampeche, with another weak trough extending from the nearshore \nwaters of SE Texas to near Veracruz, Mexico. Scattered showers are\nwithin 90 nm of Veracruz and within 45 nm of the NE Mexico coast.\nFor the forecast, the pressure gradient between high pressure \nover the southeastern U.S. and a dissipating frontal trough over \nthe southern Gulf supports moderate to locally fresh E-NE to E \nwinds and moderate seas over the northern Gulf. These conditions \nwill gradually improve later today into Sat as the frontal trough\ndissipates. Meanwhile, a rather broad upper-level low will move \ntowards Florida from the western Atlantic today, and into the NE \nGulf on Sat. This feature will lead to increasing shower and \nthunderstorm activity over Florida, and then over the eastern and \ncentral Gulf waters. Fairly tranquil marine conditions are \nforecast by the end of the weekend into early next week. \n...CARIBBEAN SEA...\nPlease refer to the tropical wave section for details on a wave in\nthe central Caribbean including associated convection. Westerly\nwinds aloft across the northwest Caribbean are supporting\nscattered moderate convection across the Gulf of Honduras and near\nthe tropical wave. Elsewhere, fair skies prevail across the \nbasin.\n \nThe pressure gradient between weakening high pressure over the \nwestern Atlantic and relatively lower pressure in northern South \nAmerica is allowing for fresh to strong trades over the central \nCaribbean S of 17N between 66W and 77W, where seas are 6-9 ft. \nModerate to fresh trades are found elsewhere from 10N to 19N to \nthe east of 80W, along with 4-7 ft seas. Gentle to moderate winds \nand 2-5 ft seas prevail across the remainder of the basin, except\nfor seas to 6 ft across southwest portions across the western\ncoastal waters of Panama. \nFor the forecast, the pressure gradient between high pressure over the\nwestern Atlantic and the Colombian Low will generally maintain\nfresh to strong trades along with moderate to locally rough seas\nover most of the central Caribbean through early Sat morning. Winds\nwill diminish to moderate to fresh speeds thereafter as the pressure\ngradient relaxes across the area. Moderate or weaker winds and slight\nto moderate seas are forecast elsewhere. \n...ATLANTIC OCEAN...\nA weakening stationary front extends from near 31N70W southwestward\nto near the coast of Vero Beach, Florida, where it becomes ill\ndefined across the peninsula. across the NW Bahamas and to the \nFlorida Keys. Broad upper level low pressure over northern Florida\nis promoting unstable conditions across much of the area W of \n68W. Converging low level moisture associated with the front is \nproducing scattered moderate isolated strong convection from 23N \nto 28.5N between the Straits of Florida and 68W. Recent satellite \nscatterometer data shows gentle to moderate NE winds to the N of \nthe front, where seas are 4 to 6 ft. S of the front, winds are \nlight to gentle between 60W and S Florida, except for fresh SE \nwinds along the N coastal waters of Hispaniola to 22N. Weak high \npressure and light winds prevail E of the front to about 46W, \nwhere a low level trough is interacting with an upper- level \ntrough to produce scattered to locally numerous moderate \nconvection from 24.5N to 31N between 40W and 55W. Farther NE, a \n1023 mb is centered near 35N45W and extends a broad ridge south \nand southwestward across the eastern and central Atlantic. \nModerate NE to E trades prevail S of 25N between the Cabo Verdes \nand the tropical wave along 40W, where seas are 5 to 7 ft. Well to\nthe east, fresh to strong N-NE winds and 6-9 ft seas are found \nfrom 16N to 22N between Africa and 22W due to a tight pressure \ngradient between low pressure across NW Africa and the Atlantic \nridge. Moderate to fresh N-NE winds and 6-9 ft seas elsewhere from\n16N to 31N to the east of 28W. Moderate or weaker winds and \nmoderate seas dominate the remainder of the tropical Atlantic \nwaters.\nFor the forecast west of 55W, a weakening stationary front that \nextends from near Bermuda to the central Florida coast will \ngradually wash out today. Conditions will improve early on Fri as \nhigh pressure becomes the dominant feature across the basin during\nthe weekend into early next week. Meanwhile, abundant tropical \nmoisture, combined with an upper- level low located east of \nFlorida, will continue to support scattered to numerous showers \nand thunderstorms, mainly W of 70W, through at least Sun. \n", "title": "Atlantic Tropical Weather Discussion", "id": "1211365000886616066", "issued": "2026-09-18T18:15:00Z", "wmo": "AXNT20", "source": "NOAA/NWS National Hurricane Center, received via the National Weather Wire Service", "page": "https://hurricane.terrapin.com/text/1211365000886616066"}