Eastern Pacific Tropical Weather Discussion
507 AXPZ20 KNHC 232150 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Aug 23 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 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Iselle is centered near 16.9N 115.1W at 23/2100 UTC, moving northwest at 14 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas are 15 ft. Numerous moderate to strong convection is noted within 180 nm SW semicircle. Iselle is moving toward the northwest, and this motion is expected to continue through Monday, followed by a gradual turn toward the west-northwest on Tuesday. Some strengthening is forecast during the next day or two, and Iselle could become a hurricane Monday night or early Tuesday. Swells generated by Iselle will affect the west coast of the Baja California Peninsula beginning Monday. These swells are likely to cause life-threatening surf and rip current conditions. 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 Iselle NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Central East Pacific (EP91): Disorganized showers and thunderstorms are persisting with a broad area of low pressure located well to the south-southwest of the southern tip of the Baja California Peninsula. Environmental conditions could support the development of a short-lived tropical depression during the next couple of days before it becomes absorbed by Tropical Storm Iselle. This system has a medium chance for tropical cyclone formation through 48 hrs, and also through 7 days. Please refer to the latest NHC Tropical Weather Outlook at website: https://www.nhc.noaa.gov/text/MIATWOEP.shtml for more details on these systems. ...TROPICAL WAVES... A tropical wave is along 87W from 04N to 20N moving westward at 15 kt. Scattered moderate to isolated strong convection is noted from 03N to 10N between 87W and 92W. The wave appears to enhance some convective activity over parts of Nicaragua, Honduras and Costa Rica. A tropical wave is along 100W N of 04N into Mexico, moving westward at 15 kt. Scattered moderate to isolated strong convection is observed from 10N to 18N between 92W and 106W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 06N95W to 11N110W then continues SW of Iselle from 12N119W to 08N130W to beyond 07N140W. Aside from the convection related to the tropical waves, Invest area EP91 and T.S. Iselle described above, scattered moderate to isolated strong convection can be found from from 03N to 12N W of 126W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more information about T.S. Iselle and Invest area EP91. A ridge continues to dominate the offshore forecast waters of Baja California Norte supporting gentle to moderate NW winds and moderate seas. Strong winds and rough seas associated with the outer periphery of T.S. Iselle are reaching the Revillagigedo Islands, particularly Clarion Island. Recent scatterometer data provide observations of fresh to strong SE to S winds in the Gulf of California N of 27N. Moderate seas are noted with these winds. Fresh to strong N gap winds persist across the Gulf of Tehuantepec and downwind to about 14.5N based on recent scatterometer data. Seas are 6 to 8 ft with these winds. For the forecast, Tropical Storm Iselle will move to 18.2N 116.3W Mon morning, 19.6N 117.8W Mon afternoon, strengthen to a hurricane near 20.8N 119.4W Tue morning, 21.4N 121.1W Tue afternoon, weaken to a tropical storm near 21.9N 122.8W Wed morning, and 22.4N 124.6W Wed afternoon. Iselle will change little in intensity as it moves to near 23.3N 128.4W Thu afternoon. A ridge will persist between Baja California and Iselle through about midweek supporting gentle to moderate NW to N winds north of Cabo San Lazaro. Stronger winds and higher seas are expected across the forecast zone between Cabo San Lazaro and Cabo San Lucas, including the Revillagigedo Islands, due to the proximity of Iselle. The forecast calls for storm conditions in the Revillagigedo Islands tonight, and storm conditions possible in the Revillagigedo Islands and the forecast zone between Cabo San Lazaro and Cabo San Lucas on Mon. The fresh to locally strong winds over the north and central parts of the Gulf of California will diminish by tonight. Fresh northerly gap winds will continue to pulse to strong speeds across Tehuantepec region mainly during the overnight and early morning hours through the next several days, 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 90W, where seas are 6 to 8 ft. Moderate or weaker winds are found elsewhere, with moderate seas in SW swell. For the forecast, high pressure will persist over the eastern Gulf of America and northwestern Caribbean leading to fresh NE to E gap winds pulsing to strong speeds over the Papagayo region each evening and night through Wed night. Moderate to fresh winds extending well downwind of Papagayo will impact the outer waters offshore of El Salvador and Guatemala through the middle of the week. South of the monsoon trough, gentle to locally moderate winds will persist through Wed night. Additional pulses of long period SW swell will continue to propagate across the area with moderate to locally rough seas. ...REMAINDER OF THE AREA... Please see the Special Features section for more information about T.S. Iselle and Invest area EP91. High pressure of 1024 mb located near 32N143W extends a ridge southeastward into the northern forecast waters to offshore of Baja California Norte. Under the influence of this system, and outside of Iselle, moderate to locally fresh N to NE winds are observed based on scatterometer data N of 15N and W of 120W. Fresh NE to E winds are seen from 10N to 15N W of 125W. Moderate or weaker winds and moderate seas in mixed swell prevail elsewhere. For the forecast, an area of low pressure is expected to develop well south of the southern tip of the Baja California Peninsula during the middle portion of this week. Some slow 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. This system has a medium chance for tropical cyclone formation through 7 days. Looking ahead, another area of low pressure could form well offshore of Central America and southern Mexico late this week. Environmental conditions appear favorable for gradual development over the weekend as the system 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.