Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Aug 15 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 0000 UTC surface analysis and satellite imagery through 0130 UTC. ...SPECIAL FEATURES... Tropical Depression Hernan is centered near 16.2N 132.9W at 15/0300 UTC, moving west at 12 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are around 10 ft or 3.0 m. Hernan has scattered moderate and isolated strong convection is noted within 120 nm in the NE quadrant with another cluster displaced beyond and between 180 nm and 390 nm also in the NE quadrant. The depression is moving toward the west and this motion is expected to continue through early next week. Slow weakening is forecast during the next 48 hours, and Hernan is forecast to become a post-tropical cyclone within the next day or so. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Hernan NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 82W north of 06N to across portions of western Costa Rica and continuing in the western Caribbean Sea, moving west around 20 to 25 kt. Nearby convection is discussed in the ITCZ/monsoon trough section below. The axis of a tropical wave is near 100.5W north of the Equator to near southwestern Mexico near the coast of Guerrero, moving west around 15 kt. Nearby convection is discussed in the ITCZ/monsoon trough section below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 1006 mb low pressure over northern Colombia at 08.5N75W to along southern Panama near 07N80W to 09N91W to 07N103W. The ITCZ begins there and extends to southeast of Tropical Depression Hernan at 15N126W. Isolated to widely scattered moderate and isolated strong convection is noted from 05N to 10N between 80W and 85W, from 03N to 08.5N between 86W and 100.5W, from 04N to 13N between 100.5W and 117W, and within 270 nm either side of the ITCZ between 117W and 126W. Similar convection is from 04N to 09N between 128W and 136W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to locally strong N gap winds are occurring over the Gulf of Tehuantepec this evening. Moderate to locally fresh NW winds are near the Pacific coast of Baja California. Elsewhere, winds are moderate or weaker. Seas are 5-7 ft over the Gulf of Tehuantepec, 4-6 ft over the remaining Pacific waters, and 1-3 ft over the Gulf of California. No significant deep convection is occurring over the Mexican offshore zones. For the forecast, high pressure over the Gulf of America will continue to force pulses of fresh to strong with locally near- gale N winds over the Gulf of Tehuantepec for the next several days. Additionally, moderate to fresh NW winds are forecast off of the Baja California peninsula through Mon night, locally strong at times. Moderate to fresh SE winds may move up the Gulf of California Mon night and Tue. Elsewhere, winds and seas should remain quiescent until at least mid next week. Looking ahead, an area of low pressure could form several hundred nautical miles south of the coast of southern Mexico by the early to middle part of next week. Some gradual development of this system is possible thereafter while the system moves westward or west-northwestward well south of Mexico. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E gap winds are observed this evening over the Gulf of Papagayo region with seas 5-7 ft. Elsewhere, winds are moderate or weaker across forecast waters. Seas are 4-7 ft in SW swell over the remainder of forecast waters. Isolated to widely scattered convection is present as described with the monsoon trough above. For the forecast, high pressure over the W Caribbean will contribute toward fresh to strong E gap winds over the Gulf of Papagayo region through Sun night before weakening early next week with winds diminishing to moderate to fresh there. 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. ...REMAINDER OF THE AREA... Please see Special Features section above for more on Tropical Depression Hernan. Surface ridging extends from 30N131W to 27N119W to 17N111W. Aside from conditions associated with Hernan, moderate to fresh winds are across the remainder of the waters from 14N to 24N to the west of 122W. Seas are 7-10 ft across those waters. Winds are moderate or weaker across the remainder of the waters north of the Equator with seas of 5-7 ft. Moderate to fresh SE winds and 7-9 ft seas are found south of the Equator. Any convection is described above in the monsoon trough/ITCZ section. For the forecast, Tropical Depression Hernan will move to 16.3N 134.5W Sat morning, become a remnant low and move to 16.4N 136.6W Sat evening, 16.5N 138.6W Sun morning, 16.6N 140.8W Sun evening, 16.7N 142.5W Mon morning, and dissipate Mon evening. Moderate to fresh SE winds will prevail south of the Equator. Rough seas will pulse on either side near the Equator to the east of 130W through the next several days in persistent and reinforced southerly swells. Looking ahead, an area of low pressure could form well to the west-southwest of the southern tip of the Baja California Peninsula by the early to middle part of next week. Gradual development of this system is possible thereafter while it moves generally westward across the western portion of the east Pacific. Additionally, an area of low pressure could form several hundred nautical miles south of the coast of southern Mexico by the early to middle part of next week. Some gradual development of this system is possible thereafter while the system moves westward or west-northwestward well south of Mexico.