Eastern Pacific Tropical Weather Discussion
291 AXPZ20 KNHC 161539 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Aug 16 2026 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Heavy Precipitation in South Central America and Colombia: A tropical wave crossing Central America and Colombia interacting with the monsoon trough will combine with enhanced divergence aloft over the next few days to including heavy rainfall over the Darien region of Panama and the Choco-Colombia into Mon. There is some uncertainty on how far south the heaviest rainfall could reach, particularly due to how far south the available moisture and the westerly flow enters the region. ...TROPICAL WAVES... The axis of a tropical wave is along 89.5W north of 02N near the Galapagos Islands to inland eastern El Salvador and western Honduras, moving westward at 10 to 15 kt. Low pressure could form in association with this wave around the middle part of the week several hundred miles south of the coast of southern Mexico, and gradual tropical development is possible of this low thereafter. Nearby convection is discussed in the ITCZ/monsoon trough section below. The axis of a tropical wave is near 116W, south of 17W, moving westward at around 20 kt. No significant convection is associated with this wave at this time. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near 10N75W to 08N100W to 07N117W. The ITCZ extends from 07N116W to 08N135W . Scattered to numerous moderate isolated strong convection is noted from 02N to 13N between 77W and 94W, and from 02N to 09N between 94W and 104W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Tropical Waves section above for information on a tropical wave that has a potential for tropical development offshore southern Mexico next week. Fresh to near gale north gap winds are over the Gulf of Tehuantepec. Moderate to fresh northwest winds are near the Pacific coast of Baja California. Elsewhere, winds are moderate or weaker. Seas are 7 to 10 ft over the Gulf of Tehuantepec, 5 to 7 ft over the remaining open Pacific offshore waters, and 1 to 3 ft over the Gulf of California. Scattered moderate convection is noted in the offshore waters of Chiapas and Oaxaca. For the forecast, the pressure gradient between high pressure over the Gulf of America and relatively lower pressure south of Mexico will continue to induce pulses of fresh to strong north winds over the Gulf of Tehuantepec through Wed night, then moderate to fresh thereafter. Winds may reach near gale force at times through Tue night, while rough seas are also expected. Moderate to fresh northwest winds are forecast off of the Baja California peninsula through Tue night, with winds reaching strong speeds near Punta Eugenia. Elsewhere, mainly moderate or weaker winds and moderate seas are forecast. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong northeast to east gap winds are over the Gulf of Papagayo region. Seas there are 7 to 10 ft downwind to near 10N90W. Elsewhere, winds are moderate or weaker north of the monsoon trough, and moderate to fresh south of the monsoon trough. Seas are 4 to 7 ft in long-period southwest swell over the remainder of forecast waters. Very active convection is present near the monsoon trough as described above across much of the offshore waters, with locally higher winds and seas possible near any convection. For the forecast, the pressure gradient between high pressure over the western Caribbean and relatively lower pressure over Central America will lead to fresh to strong northeast to east gap winds over the Gulf of Papagayo region through tonight before weakening with winds diminishing to moderate to fresh through Tue, then back to fresh to strong thereafter. Moderate to fresh southerly winds will pulse south of the monsoon trough through Mon. Large southerly swell will impact the waters mainly from Ecuador to the Galapagos Islands through the next several days, largest expected by around the middle portion of the week. ...REMAINDER OF THE AREA... Weakening low pressure of 1009 mb associated with the remnants of Hernan is centered near 16N138W. It is producing fresh winds in the northern semicircle and rough seas in the surrounding waters. Scattered moderate convection is noted between 90 nm and 180 nm in the NE quadrant. Moderate to locally fresh winds are found elsewhere from 15N to 23N between 130W and 140W, and from 08N to 21N between 118W and 130W. Moderate to fresh southerly winds are found south of the Equator. Moderate or weaker winds dominate the remainder of the waters. Seas are 7 to 10 ft south of about 02N between 90W and 121W, amd 5 to 7 ft across the remainder of the waters. For the forecast, moderate to fresh southeast winds will prevail south of the Equator. Rough seas will pulse on either side near the Equator to the east of about 130W over the next several days in persistent and reinforced southerly swells. The remnants of Hernan and associated residual winds and seas will shift of 140W by this evening. Looking ahead, an area of low pressure could form several hundred nautical miles south of the coast of southern Mexico around the middle portion of next week. Gradual development of this system is possible thereafter, and a tropical depression could form late next week or over the weekend while the system moves west-northwestward, well south of Mexico. Additionally, an area of low pressure is expected to form well to the west-southwest of the southern tip of the Baja California Peninsula early next week. Environmental conditions appear conducive for gradual development of this system, and a tropical depression could form during the middle to latter portions of next week while it moves generally westward across the western portion of the east Pacific. Regardless of development, expect some increasing winds and seas with this area.