--------------------------------------------------------------------------- TROPICAL WEATHER DISCUSSION (NORTH ATLANTIC AREA) MESSAGES T1T2: AX A1A2: NT Date: 2026-09-15 --------------------------------------------------------------------------- Message File: T_AXNT20KNHC150402_C_KWBC_20260915040258_31523192-3596-TWDAT.txt ****0000006793**** AXNT20 KNHC 150402 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0015 UTC Tue Sep 15 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 0330 UTC. ...TROPICAL WAVES... A tropical wave axis is along 54W, S of 20N, moving west at 10 to 15 kt. Scattered moderate isolated strong convection is depicted from 12N to 17.5N between 50W and 56W. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic along the coast of Guinea near 10.5N14.5W and continues to 11N21W to 07.5N43W. The ITCZ extends from 09N44W to 11N54W. Numerous strong convection is from 06N to 14N E of 18W to the coast of Africa. Scattered moderate convection is noted from 06.5N to 13N between 18W and 28W, and from 06.5N to 12.5N between 28W and 50W. ...GULF OF AMERICA... Widely scattered showers prevail across the basin from 23N to 28N, supported by a weakening middle to upper-level trough from the Yucatan Channel to SE Texas. Evening convection across much of interior Florida continues to shift southwestward and weaken as it reaches the western coastal waters of Florida. At the surface, a 1017 mb high pressure center is just offshore SE Louisiana, and dominates the Gulf waters with anticyclonic flow. Recent scatterometer data shows light to gentle winds across the basin E of 92W, while fresh to locally strong NE winds prevail wihtin 120 nm of the coast of the Yucatan Peninsula and over the eastern Bay of Campeche, and moderate SE winds are W of 95W. Seas are generally 3 ft or less, except 3-5 ft near the Yucatan Peninsula, and 3 to locally 4 ft W of 95W. For the forecast, a weak ridge centered over the noreth-central Gulf will persist into Tue supporting relatively tranquil marine conditions across much of the basin. The exception will be the Bay of Campeche, where a diurnal trough will move westward offshore the Yucatan Peninsula each evening through late this week, bringing nightly pulses of fresh to locally strong NE winds. Starting late Tue, stronger high pressure building southward from the eastern United States, behind a weakening frontal boundary, will lead to increasing NE to E winds over the basin, with increasing winds reaching fresh to locally strong speeds, and seas building to rough over the northern Gulf Wed through Thu night. Conditions will improve Fri through Sat. ...CARIBBEAN SEA... A persistent middle to upper-level low pressure system prevails across the Greater Antilles tonight, and is supporting scattered moderate convection between Haiti and 80W, and scattered light to moderate convection across the eastern Caribbean. At the surface, weak high pressure is centered just northeast of the NW Bahamas, and extends a ridge to 60W. The pressure gradient between this ridge and lower pressures in Colombia combine to sustain fresh to strong with locally near gale-force easterly trade winds across much of the central Caribbean between 68W and 78W, as well as the Windward Passage. Seas are 6 to 9 ft across this area. Elsewhere, moderate to fresh trades prevail elsewhere, except light winds across far NW portions. Scattered to locally numerous heavy showers and thunderstorms are ongoing over the SW Caribbean between Colombia and NE Nicaragua, along the eastern extension of the E Pacific monsoon through. For the forecast, the pressure gradient between the subtropical ridge located north of the Greater Antilles and lower pressures in Colombia will support fresh to locally near gale-force easterly trade winds and moderate to rough seas across much of the central Caribbean, with moderate to fresh trades elsewhere through the workweek. Expect moderate or lighter winds and slight to moderate seas across NW portions, except for moderate to fresh winds mainly in the evenings near the Windward Passage and Lee of Cuba through midweek. Winds may diminish across the basin by the end of the week into the upcoming weekend as the pressures gradient relaxes. ...ATLANTIC OCEAN... A broad ridge dominates much of the Atlantic basin N of 10N and E of 60W, producing moderate to fresh easterly winds between 30W and 60W, except for fresh winds and scattered moderate convection near the tropical wave along 54W. A deep layered upper cyclone is interacting with a surface trough from 31N53W to 24N50W, producing scattered moderate isolated strong convection from 27N to 31N between 44W and 53W. Fresh SE winds and seas of 5 to 6 ft are occurring across NE portions of this trough. Environmental conditions near this system are forecast to become more conducive for development by the middle of this week. A tropical depression could form late this week as the system moves slowly west- northwestward over the subtropical Atlantic. There is a medium chance of tropical cyclone development within the next seven days. To the W of 60W, a 1018 mb high center is analyzed near 28N74W, and extends a weak ridge to 60W. The pressure gradient to the S of this ridge is promoting moderate to fresh trades S of 23N and through the Bahamas, with strongest winds off Hispaniola and in the Windward Passage. Elsewhere W of 30W, moderate or weaker winds and moderate seas prevail over the central and eastern subtropical waters. Broad low pressure along the NW coast of Africa in recent days has weakened and drifted westward over the Atlantic waters between NW Africa and 35W, where gentle to moderate NE to E winds generally prevail N of 10N, with seas of 4 to 6 ft. For the forecast west of 55W, a broad and weak subtropical ridge dominates much of the basin, forcing fresh E winds off Hispaniola and in the Windward Passage. On Tue, strong high pressure building southward through the eastern United States will bring a cold front into the NW waters, increasing NE winds to fresh to locally strong behind the front, and producing building seas to rough N of the Bahamas and W of 70W through early Thu. Conditions will improve later Thu into Fri. During the middle to later portion of the week, a trough of low pressure is forecast to move west- northwestward into the NE portion of the waters, bringing thunderstorms while also weakening the high and pressure gradient. $$ Stripling ########################### END OF MESSAGE SET ############################