{"msg": "642\nAXNT20 KNHC 150402\nTWDAT \nTropical Weather Discussion\nNWS National Hurricane Center Miami FL\n0015 UTC Tue Sep 15 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 0000 UTC surface analysis and satellite imagery through \n0330 UTC.\n...TROPICAL WAVES...\nA tropical wave axis is along 54W, S of 20N, moving west at 10 to\n15 kt. Scattered moderate isolated strong convection is depicted \nfrom 12N to 17.5N between 50W and 56W. \n...MONSOON TROUGH/ITCZ...\nThe monsoon trough enters the Atlantic along the coast of Guinea \nnear 10.5N14.5W and continues to 11N21W to 07.5N43W. The ITCZ\nextends from 09N44W to 11N54W. Numerous strong convection is from\n06N to 14N E of 18W to the coast of Africa. Scattered moderate \nconvection is noted from 06.5N to 13N between 18W and 28W, and \nfrom 06.5N to 12.5N between 28W and 50W.\n \n...GULF OF AMERICA...\nWidely scattered showers prevail across the basin from 23N to 28N,\nsupported by a weakening middle to upper-level trough from the\nYucatan Channel to SE Texas. Evening convection across much of\ninterior Florida continues to shift southwestward and weaken as it\nreaches the western coastal waters of Florida. At the surface, a \n1017 mb high pressure center is just offshore SE Louisiana, and \ndominates the Gulf waters with anticyclonic flow. Recent\nscatterometer data shows light to gentle winds across the basin E\nof 92W, while fresh to locally strong NE winds prevail wihtin 120\nnm of the coast of the Yucatan Peninsula and over the eastern Bay\nof Campeche, and moderate SE winds are W of 95W. Seas are\ngenerally 3 ft or less, except 3-5 ft near the Yucatan Peninsula,\nand 3 to locally 4 ft W of 95W.\nFor the forecast, a weak ridge centered over the noreth-central \nGulf will persist into Tue supporting relatively tranquil marine \nconditions across much of the basin. The exception will be the Bay\nof Campeche, where a diurnal trough will move westward offshore \nthe Yucatan Peninsula each evening through late this week, \nbringing nightly pulses of fresh to locally strong NE winds. \nStarting late Tue, stronger high pressure building southward from \nthe eastern United States, behind a weakening frontal boundary, \nwill lead to increasing NE to E winds over the basin, with\nincreasing winds reaching fresh to locally strong speeds, and seas\nbuilding to rough over the northern Gulf Wed through Thu night. \nConditions will improve Fri through Sat. \n...CARIBBEAN SEA...\nA persistent middle to upper-level low pressure system prevails\nacross the Greater Antilles tonight, and is supporting scattered\nmoderate convection between Haiti and 80W, and scattered light to\nmoderate convection across the eastern Caribbean. At the surface,\nweak high pressure is centered just northeast of the NW Bahamas, \nand extends a ridge to 60W. The pressure gradient between this \nridge and lower pressures in Colombia combine to sustain fresh to \nstrong with locally near gale-force easterly trade winds across \nmuch of the central Caribbean between 68W and 78W, as well as the \nWindward Passage. Seas are 6 to 9 ft across this area. Elsewhere, \nmoderate to fresh trades prevail elsewhere, except light winds \nacross far NW portions. Scattered to locally numerous heavy \nshowers and thunderstorms are ongoing over the SW Caribbean \nbetween Colombia and NE Nicaragua, along the eastern extension of \nthe E Pacific monsoon through. \nFor the forecast, the pressure gradient between the subtropical \nridge located north of the Greater Antilles and lower pressures \nin Colombia will support fresh to locally near gale-force easterly\ntrade winds and moderate to rough seas across much of the central\nCaribbean, with moderate to fresh trades elsewhere through the \nworkweek. Expect moderate or lighter winds and slight to moderate\nseas across NW portions, except for moderate to fresh winds mainly\nin the evenings near the Windward Passage and Lee of Cuba through\nmidweek. Winds may diminish across the basin by the end of the \nweek into the upcoming weekend as the pressures gradient relaxes.\n...ATLANTIC OCEAN...\nA broad ridge dominates much of the Atlantic basin N of 10N and E\nof 60W, producing moderate to fresh easterly winds between 30W \nand 60W, except for fresh winds and scattered moderate convection \nnear the tropical wave along 54W. A deep layered upper cyclone is \ninteracting with a surface trough from 31N53W to 24N50W, producing\nscattered moderate isolated strong convection from 27N to 31N \nbetween 44W and 53W. Fresh SE winds and seas of 5 to 6 ft are \noccurring across NE portions of this trough. Environmental \nconditions near this system are forecast to become more conducive \nfor development by the middle of this week. A tropical depression \ncould form late this week as the system moves slowly west- \nnorthwestward over the subtropical Atlantic. There is a medium \nchance of tropical cyclone development within the next seven days.\nTo the W of 60W, a 1018 mb high center is analyzed near 28N74W, \nand extends a weak ridge to 60W. The pressure gradient to the S of\nthis ridge is promoting moderate to fresh trades S of 23N and \nthrough the Bahamas, with strongest winds off Hispaniola and in \nthe Windward Passage. Elsewhere W of 30W, moderate or weaker winds\nand moderate seas prevail over the central and eastern \nsubtropical waters. Broad low pressure along the NW coast of \nAfrica in recent days has weakened and drifted westward over the \nAtlantic waters between NW Africa and 35W, where gentle to \nmoderate NE to E winds generally prevail N of 10N, with seas of 4 \nto 6 ft.\nFor the forecast west of 55W, a broad and weak subtropical ridge \ndominates much of the basin, forcing fresh E winds off Hispaniola \nand in the Windward Passage. On Tue, strong high pressure building\nsouthward through the eastern United States will bring a cold \nfront into the NW waters, increasing NE winds to fresh to locally \nstrong behind the front, and producing building seas to rough N \nof the Bahamas and W of 70W through early Thu. Conditions will \nimprove later Thu into Fri. During the middle to later portion of \nthe week, a trough of low pressure is forecast to move west- \nnorthwestward into the NE portion of the waters, bringing \nthunderstorms while also weakening the high and pressure gradient.\n", "title": "Atlantic Tropical Weather Discussion", "id": "1210366598869614594", "issued": "2026-09-15T00:15:00Z", "wmo": "AXNT20", "source": "NOAA/NWS National Hurricane Center, received via the National Weather Wire Service", "page": "https://hurricane.terrapin.com/text/1210366598869614594"}