Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2000 UTC. ...SPECIAL FEATURES... Heavy Rainfall in Panama and Colombia: A tropical wave will cross Panama and northern Colombia through Mon, interacting with the monsoon trough and combining with enhanced divergence aloft to induce thunderstorms, particularly over the Darien region of Panama and the Choco-Colombia. Heavy rainfall from these thunderstorms may lead to flooding. ...TROPICAL WAVES... The axis of a tropical wave is along 92W from the Galapagos Islands northward to Guatemala, moving westward at 10 to 15 kt. An area of low pressure could form in association with this tropical wave, several hundred miles south of the coast of southern Mexico around the middle part of next week. Gradual development of the low is possible thereafter, and a tropical depression could form toward the end of the week or during the weekend. Nearby convection is discussed in the ITCZ/monsoon trough section below. The axis of a tropical wave is near 118W, south of 17W, moving westward at around 15 kt. No significant convection is associated with this wave at this time. Broad low pressure may form in association with this wave well southeast of the Hawaiian Islands during the middle to latter part of next week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near 09N76W to 08N97W to 07N112W. The ITCZ extends from 07N112W to 07N116W and from 06N120W to 08N135W. Numerous moderate to isolated strong convection is noted from 02N to 13N E of 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. Strong to near gale north gap winds are over the Gulf of Tehuantepec. Fresh northwest winds are near the Pacific coast of Baja California. Elsewhere, winds are moderate or weaker. Seas are 6 to 8 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 from Guerrero southward. 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 strong north winds over the Gulf of Tehuantepec through Wed night, with moderate to fresh pulses thereafter. Winds will reach reach near gale force at times Mon and Tue nights, while rough seas are also expected. Fresh northwest winds are forecast off of the Baja California peninsula through Tue night, with winds reaching strong speeds near Punta Eugenia. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See Special Features section above for information on heavy rainfall that may cause flooding over the next few days in portions of Colombia and Panama. Fresh to strong northeast to east gap winds are over the Gulf of Papagayo region. Seas there are 7 to 9 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. Thunderstorms are 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. Similar conditions will return starting late Tue. Moderate to fresh southerly winds will pulse south of the monsoon trough into Mon night. Large southerly swell will impact the waters mainly from Ecuador to the Galapagos Islands through the next several days, largest expected Tue and Wed. ...REMAINDER OF THE AREA... The low pressure associated with the remnants of Hernan is opening to a surface trough as it moves W to around 140W. Fresh E winds and rough seas are still noted from about 17N to 20N W of 136W, but associated convection has dissipated this afternoon. Mainly moderate winds and seas dominate much of the remaining waters, with easterly winds N of the monsoon trough and ITCZ, SE winds S of the ITCZ, and SW winds S of the monsoon trough. Some rough seas are noted S of the Equator, where SW long period swell is most significant. For the forecast, winds and seas associated with the remnants of Hernan will diminish tonight toward 140W. Rough seas will prevail along and south of the Equator through the middle of next week. An area of low pressure could form several hundred miles south of the coast of southern Mexico around the middle part of the week. Gradual development of this system is possible thereafter, and a tropical depression could develop towards the end of the week or during the weekend while the system moves west-northwestward, while staying south of Mexico. In addition, a broad area of low pressure could form well to the southeast of the Hawaiian Islands during the middle to latter part of the week. Environmental conditions appear conducive for gradual development of this system, and a tropical depression could form towards the end of the week and into the weekend, while the system moves generally westward across the western portion of the east Pacific and into the central Pacific. Regardless of development, expect some increasing winds and seas with this area.