Tropical Weather Discussion
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Issued by NWS
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036 AXPZ20 KNHC 171529 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Aug 17 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 Rainfall Colombia: A tropical wave, currently analyzed near 77W, will cross NW Colombia through tonight, interacting with the monsoon trough and combining with enhanced divergence aloft to induce numerous thunderstorms over the Choco-Colombia. Heavy rainfall from these thunderstorms may lead to flooding. Conditions should improve Tuesday as the wave moves into the Eastern Pacific. ...TROPICAL WAVES... The axis of a tropical wave is along 77W from 02N near the border of Ecuador and Colombia northward to across eastern Panama near the border with Colombia, and continuing into the Caribbean Sea, moving westward around 15 kt. Refer to the Special Features section below for additional details including Heavy Rainfall. The axis of a tropical wave is along 98W from just offshore Oaxaca southward to the Equator, moving westward around 25 kt. Scattered moderate convection is noted from 07N to 13N between 93W and 100W. An area of low pressure is likely to form in association with this wave several hundred miles south of the coast of southern Mexico late this week. Gradual development of this system is expected at a tropical depression may form by this weekend as the low moves west-northwest while staying south of Mexico. The axis of a tropical wave is near 124W from 16N southward, moving westward at around 15 kt. Scattered moderate convection is noted east of this wave from 07N to 12N between 114W and 124W. A broad area of low pressure could form well to the southeast of the Hawaiian Islands during the latter part of the week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 1007 mb low pressure near the coast of northern Colombia at 10N73W to across the border of Costa Rica and Nicaragua to the Gulf of Papagayo at 11N85W to 07N102W. The ITCZ extends from 07N102W to 08N122W, then resumes west of a tropical wave from 07N125W to beyond 05N140W. Scattered to numerous moderate and isolated strong convection is noted from 02N to 14N between 77W and 93W, and from 05N to 13N between 124W and 131W. ...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 late this 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, locally strong near and north of Punta Eugenia. Elsewhere, winds are moderate or weaker. Seas are 7 to 10 ft over the Gulf of Tehuantepec, 4 to 6 ft over the remaining open Pacific offshore waters, except to 7 ft near Punta Eugenia, and 1 to 3 ft over the Gulf of California. A surface trough extending SE from just offshore Cabo Corrientes is inducing numerous moderate to isolated strong convection between its axis and the coast, leading to gusty winds and squally weather, including locally higher seas. 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 tonight and Tue night, with resultant rough seas. Fresh northwest winds are forecast off of the Baja California peninsula through Tue night, with winds reaching strong speeds near Punta Eugenia through this evening. Meanwhile, a surge of strong SE winds may move from N of Cabo Corrientes into the southern Gulf of California tonight into early Tue, likely associated with a complex of convection. ...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 day or so in portions of Colombia. Fresh northeast to east gap winds are over the Gulf of Papagayo region. 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, except to 8 ft southwest of the Galapagos Islands. For the forecast, the pressure gradient between high pressure over the western Caribbean and relatively lower pressure over Central America will lead to fresh northeast to east gap winds over Papagayo region, locally strong to near gale-force at times with occassionally and locally rough seas as a result. Moderate to fresh winds will extend away from this area across the far offshore waters of El Salvador and Guatemala midweek. Moderate to fresh southerly winds will pulse south of the monsoon trough into tonight before weakening. Large southerly swell will impact waters mainly from Ecuador to the Galapagos Islands through the next several days, largest expected later today through Wed. ...REMAINDER OF THE AREA... See Tropical Waves section above for information on a tropical wave in the western basin that has potential for tropical develop late this week. A surface trough is over the northwest waters, analyzed from 23N130W to 18N140W, with moderate to fresh winds from 17N to 24N to the west of 130W and the trough. Associated scattered moderate isolated strong convection is found from 24N to 28N between 125W and 134W. Some moderate to fresh winds are also noted from 09N to 24N between 117W and 130W near a tropical wave described above. Moderate to fresh SE to S winds are found south of the monsoon trough to the east of 124W, where seas are 7 to 9 ft in mixed SE and SW swells. Winds are moderate or weaker across the remainder of the open waters, along with seas of 4 to 7 ft. For the forecast, an area of low pressure could form several hundred nautical miles south of the coast of southern Mexico around the middle part of the week, associated with a tropical wave currently analyzed near 77W. Gradual development of this system is possible thereafter, and a tropical depression could develop towards the end of the week or next weekend as 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 latter part of the week, associated with a tropical wave currently analyzed near 124W. 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 as 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 these areas. $$ Konarik