Eastern Pacific Tropical Weather Discussion
540 AXPZ20 KNHC 250408 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Aug 25 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 0350 UTC. ...SPECIAL FEATURES... Tropical Storm Iselle is centered near 20.1N 118.6W at 25/0300 UTC, moving northwest at 13 kt. Estimated minimum central pressure is 988 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Peak seas are estimated near 28 ft. Numerous moderate to strong convection is noted from 19N to 23N between 113W and 121W, while scattered to locally numerous moderate convection extends elsewhere from 14N to 19N between 110W and 120W. A short amount of time remains for additional strengthening, and Iselle could briefly become a hurricane. Gradual weakening is then forecast starting later on Tuesday. Swells generated by Iselle are affecting the west coast of the Baja California Peninsula, and will continue for a couple more days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. Tropical Depression Ten-E is centered near 14.5N 120.3W at 25/0300 UTC, moving north-northeast at 8 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are 11 ft. Numerous moderate to strong convection is noted from 11N to 16N between 117W and 122W, while scattered to locally numerous moderate convection extends elsewhere from 06N to 13N between 120W and 130W. Slight strengthening is forecast, and the depression could become a tropical storm early Tuesday before it becomes absorbed by Iselle later that day. 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 NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details on these two systems. ...TROPICAL WAVES... A tropical wave is along 101W, from 02N to 16N, moving westward at 15 kt. Scattered to locally numerous moderate isolated strong convection is noted from 01N to 13N between 91W and 104W. A tropical wave is along 108W, from 01N to 17N, moving westward at 10 kt. Scattered moderate isolated strong convection is observed from 09N to 13N between 103W and 108W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 06N100W to 08N111W, then resumes SW of Iselle from 13N120W to 11N132W to beyond 07N140W. Aside from the convection related to the tropical waves, T.D. Ten-E and T.S. Iselle described above, scattered moderate isolated strong convection is noted from 04.5N to 10N E of 93W. Scattered moderate to strong convection is noted from 03N to 13N W of 130W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more information about T.S. Iselle. Tropical Storm Iselle is near 20.1N 118.6W at 8 PM PDT, and is moving northwest at 13 kt. Maximum sustained winds are 60 kt with gusts to 75 kt, and the minimum central pressure is 988 mb. Iselle has weakened the ridge extending into the Baja offshore waters, leading to light to gentle winds across the Baja offshore waters N of 22.5N extending into the coast. Otherwise, fresh to locally strong N to NE gap winds persist across the Gulf of Tehuantepec and downwind to about 14N with seas to 7 ft. For the forecast, Iselle will move to 20.7N 119.9W Tue morning, 21.3N 121.7W Tue evening, 21.8N 123.7W Wed morning, 22.6N 125.1W Wed evening, weaken to a tropical depression near 23.2N 127.0W Thu morning, and become a remnant low and move to 23.6N 129.1W Thu evening. Iselle will dissipate late Fri. Large southerly swell will move through the Baja offshore waters and reach the coasts through Wed morning. Elsewhere, fresh northerly gap winds will continue to pulse to strong speeds across Tehuantepec region mainly during the overnight and early morning hours through the upcoming weekend, with seas occasionally building to 8 ft. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E gap winds continue across the Papagayo region and downwind to near 91W, where seas are 6 to 8 ft. Moderate to locally fresh winds then continue to near 95W. Moderate or weaker winds are found elsewhere, with moderate seas 5 ft or less in S swell. Scattered thunderstorms extends from the coast of SE Costa Rica and western Panama westward to 90W, while a cluster of strong thunderstorms is just offshore of the coast of Colombia along 06N. For the forecast, high pressure will persist over the eastern Gulf of America and northwestern Caribbean throughout the upcoming week, leading to fresh NE to E gap winds pulsing to strong speeds over the Papagayo region each evening and night. Moderate to fresh winds extending well downwind of Papagayo will impact the outer waters offshore of El Salvador and Guatemala through the end of the week. South of the monsoon trough, gentle to locally moderate winds will persist through Sat night. Cross- equatorial SW swell will move into the area waters Thu night through Fri. ...REMAINDER OF THE AREA... Please see the Special Features section for more information about T.S. Iselle and Tropical Depression Ten-E. High pressure of 1021 mb located near 32N140W extends a broad ridge southeastward across the northern forecast waters to offshore of Baja Norte. Under the influence of this system, and west of Iselle, moderate to locally fresh N to NE winds are observed from 11N to 26N and W of 120W. Moderate or weaker winds and moderate seas in mixed swell prevail elsewhere to the north, while gentle to moderate southerly winds prevail S of the monsoon trough. For the forecast, Iselle will move to 20.7N 119.9W Tue morning, 21.3N 121.7W Tue evening, 21.8N 123.7W Wed morning, 22.6N 125.1W Wed evening, weaken to a tropical depression near 23.2N 127.0W Thu morning, and become a remnant low and move to 23.6N 129.1W Thu evening. Iselle will dissipate late Fri. An area of low pressure is expected to develop well south of the southern tip of the Baja California Peninsula during the middle part of the week. Gradual development is expected thereafter, and a tropical depression is likely to form later this week or over the weekend while the system moves generally west-northwestward at 10 to 15 kt. Looking ahead, another area of low pressure could form well offshore of Central America late this week. Environmental conditions appear conducive for some gradual development of this system over the weekend while it moves westward to west- northwestward at 10 to 15 mph well offshore of southern Mexico. This system has a low chance for tropical cyclone formation through 7 days.