{"msg": "410\nAXPZ20 KNHC 180757\nTWDEP \nTropical Weather Discussion\nNWS National Hurricane Center Miami FL\n1005 UTC Tue Aug 18 2026\nTropical Weather Discussion for the eastern Pacific Ocean from\n03.4S to 30N, east of 120W including the Gulf of California, and\nfrom the Equator to 30N, between 120W and 140W. The following\ninformation is based on satellite imagery, weather observations,\nradar, and meteorological analysis.\nBased on 0600 UTC surface analysis and satellite imagery through\n0730 UTC.\n...SPECIAL FEATURES...\nGulf of Tehuantepec Gale Warning: A very tight local pressure\ngradient is present over the Gulf of Tehuantepec area in the \nwake of a departing tropical wave with a tight ridge of high \npressure nosing down eastern to southeastern Mexico, as well as a\nsurface trough to the northeast over the western Yucatan \nPeninsula. This pressure is likely supporting minimal gale-force\nnortherly gap winds in the Gulf of Tehuantepec, with seas of 7 \nto 11 ft. Winds are forecast to diminish below gale-force to \nlater this morning. Please, refer to the latest NWS High Seas \nForecast available at website:\nhttps://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.\n...TROPICAL WAVES...\nThe axis of a tropical wave is near 80W from 03N offshore of the\nborder of Ecuador and Colombia northward to across the Gulf of\nPanama and Panama and into the western Caribbean Sea, moving \nwestward at around 20 kt. Scattered to numerous moderate and \nisolated strong convection is noted from 01N to 11N between 77W \nand 91W.\nThe axis of a tropical wave is near 100W from just south and \noffshore Guerrero, Mexico southward to near the Equator, moving \nslowly westward at around 20 kt. Scattered moderate isolated \nstrong convection is noted from 05N to 10N between 95W and 100W.\nAn area of low pressure is forecast to form several hundred\nnautical miles south of the coast of southern Mexico around the \nend of the week. Gradual development of this system is likely \nthereafter, and a tropical depression is expected to form this \nweekend while the system moves west-northwestward, remaining well\noffshore of Mexico.\nThe axis of a tropical wave is near 127W from 17N southward to\nnear the Equator, moving westward at around 10 kt. Scattered \nmoderate isolated strong convection is noted from 06N to 14N \nbetween 112W and 140W. Environmental conditions appear conducive \nfor gradual development of this system, and a tropical depression \ncould form towards the end of the week or over the weekend while the \nsystem moves generally westward across the western portion of the \neast Pacific and into the central Pacific.\n...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...\nThe monsoon trough extends from the SW Caribbean Sea to across\nCosta Rica, entering the Pacific at the coast near 09.5N84W to\n07N110W. The ITCZ extends from 07N110W to 08.5N125W, then \nresumes west of a tropical wave from 09N131W to beyond 09N140W. \nOther than the convection described above with three tropical \nwaves, scattered moderate isolated strong is noted from 00N to \n06N between 131W and 140W.\n...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...\nPlease refer to the Special Features section above for details \non a Gale Warning in effect in the Gulf of Tehuantepec until \naround sunrise this morning.\nPlease refer to the Tropical Waves section above for information\non a tropical wave that has a potential for tropical development\noffshore Mexico this upcoming weekend.\nModerate to fresh NW-N winds are found offshore Baja California \nfrom Punta Eugenia northward, locally strong near San Fernando to\nPunta San Carlos per recent ASCAT data. Fresh to strong E to SE \nwinds are surging up the along the southern to central Gulf of\nCalifornia where a strong thunderstorm complex is present. \nScattered to numerous thunderstorms are noted from 21N to 28N \nbetween mainland Mexico and Baja California Sur. Seas are 4 to \n6 ft across the remainder of the offshore waters, except 1 to 3 \nft in the Gulf of California.\nFor the forecast, the pressure gradient between high pressure \nover the Gulf of America and relatively lower pressure south of \nMexico will continue to induce pulses of strong north winds over \nthe Gulf of Tehuantepec through Wed night, to minimal gale-force\nthrough this early morning, with moderate to fresh pulses then\nstarting Thu. Seas will occasionally build to rough with the \nfresh to strong or stronger winds. A surge of strong SE winds \nwill move from the southern to central Gulf of California \ninto early today, associated with a complex of convection. Fresh\nto strong SE winds may pulse in the northern Gulf of California\ntonight. Winds and seas may build across the outer offshore \nwaters of southwestern Mexico by the end of the week into the \nupcoming weekend in association with a possibly developing area \nof low pressure beyond the offshore waters.\n...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, \nAND WITHIN 750 NM OF ECUADOR...\nSee Tropical Waves section above for information on a tropical\nwave producing heavy rainfall over portions of Colombia, Panama\nand areas northwestward, with heavy thunderstorms also over the\nadjacent offshore waters as described above.\nFresh to strong winds are in the Gulf of Papagayo per recent\nASCAT scatterometer data. Winds are moderate or weaker elsewhere,\nexcept moderate to fresh south of the monsoon trough near the\nGalapagos Islands. Seas are 4 to 7 ft in long-period S to SW \nswell, except 7 to 9 ft southwest of the Galapagos Islands. \nFor the forecast, the pressure gradient between high pressure \nover the western Caribbean and relatively lower pressure over \nCentral America will lead to pulsing strong to near gale-froce \nnortheast to east gap winds over the Papagayo region through Thu,\nwith resultant rough seas, then moderate to fresh winds \nthereafter. Moderate to fresh associated winds will extend well \ndownwind across the outer offshore waters of El Salvador and \nGuatemala at times. Moderate to fresh southerly winds south of \nthe monsoon trough will diminish later this morning. Large \nsoutherly swell will impact waters mainly from Ecuador to the \nGalapagos Islands through Thu, largest expected through tonight. \n...REMAINDER OF THE AREA...\nSee Tropical Waves section above for information on two tropical\nwaves that have potential for tropical development later this \nweek and into the upcoming weekend.\nModerate to fresh E winds are noted from near 10N to 19N between\n124W and 138W as seen by recent ASCAT scatterometer data, and \nis associated with the tropical wave at 127W. Fresh to locally\nstrong winds and seas of around 8 ft are from 09N to 11N between\n98W and 103W as seen by ASCAT, and are associated with the\ntropical wave at 100W. Moderate to fresh winds and rough seas \nare also found south of 04N between 90W and 140W. Rough seas are\nsouth of 04N between 88W and 128W in SE to S swell, except in \nthe lee of the Galapagos Islands. Winds are moderate or weaker \nacross the remainder of the open waters, with seas of 4 to 7 ft.\nFor the forecast, regardless of tropical development, the \ntropical waves described in the above section will bring some \nincreasing winds and seas to area waters. Away from these waves, \nlittle change is expected in marine weather through the week,\nwith conditions a bit more tranquil across the open waters by the\nupcoming weekend.\n", "title": "Eastern Pacific Tropical Weather Discussion", "id": "1202485657313705991", "issued": "2026-08-18T10:05:00Z", "wmo": "AXPZ20", "source": "NOAA/NWS National Hurricane Center, received via the National Weather Wire Service", "page": "https://hurricane.terrapin.com/text/1202485657313705991"}