


Tropical Weather Discussion
Issued by NWS
Issued by NWS
464 AXPZ20 KNHC 041551 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Oct 4 2025 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... Tropical Storm Octave is centered near 14.6N 123.6W at 04/1500 UTC, moving northwest at 6 kt, and a gradual turn toward the north is expected tonight and tomorrow. Early next week, the tropical storm is expected to turn northeastward and then eastward. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Slight strengthening is possible during the next day or two. Peak seas are 20 ft. Numerous moderate to strong convection is observed within 120 nm SW semicircle. Please read the latest NWS HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Octave NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Offshore of the Southwestern Coast of Mexico (EP99): Showers and thunderstorms associated with a broad area of low pressure a few hundred miles off the southwestern coast of Mexico continue to become better organized this morning. If current trends persist, advisories on a tropical depression could be initiated later today or tonight. The system is forecast to move slowly west-northwestward, remaining offshore of the southwestern coast of Mexico during the next several days. Interests along the southwestern coast of Mexico should continue to monitor the progress of this system. For additional information, including gale warnings, please see High Seas Forecasts issued by the National Weather Service. Please read the latest TROPICAL WEATHER OUTLOOK issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIATWOEP.shtml and the latest NWS HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N83W to 12N95W to low pressure located near 15N105.5W, then resumes SW of Octave from 11N126W to 09N140W. Aside from the convection associated with Octave and EP99, scattered moderate to isolated strong convection is noted from 07N to 13N between 90W and 100W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for details on Invest EP99 that has a high chance for tropical cyclone formation within the next 48 hours. A Gale Warning is in effect for this system. A ridge dominates the offshore forecast waters of Baja California supporting moderate to fresh NW to N winds north of Cabo San Lazaro and light to gentle winds between Cabo San Lazaro and Cabo San Lucas. Light and variable winds and slight seas prevail in the Gulf of California. Winds and seas are on increase across the Mexican offshore forecast waters between Acapulco and Manzanillo due to the presence of EP99. Fresh to strong northerly winds are noted across the Tehuantepec region based on latest scatterometer pass. For the forecast, a ridge will continue to dominate the offshore forecast waters of Baja California this weekend supporting moderate to fresh NW to N winds N of Cabo San Lazaro, and gentle to moderate winds between Cabo San Lazaro and Cabo San Lucas. Marine conditions are forecast to deteriorate across the Mexican offshore waters S of Cabo Corrientes this weekend due to a developing tropical cyclone. Fresh to strong N to NE winds in the Gulf of Tehuantepec will diminish below 20 kt later today. Looking ahead, an area of low pressure is expected to form off the southern coast of Mexico by the middle of next week. Gradual development of this system is possible thereafter, and a tropical depression could form during the middle to latter part of next week while moving west-northwestward to northwestward, near or parallel to the coast of Mexico. This system has a medium change of tropical cyclone formation through 7 days. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Unsettled weather conditions persist across the offshore waters of Central America and Colombia. Meanwhile, a weak pressure gradient continues to influence the region, sustaining gentle to moderate S to SW winds S of the monsoon trough and light to gentle winds to the N of it. Moderate seas in SW swell dominate the area. For the forecast, gentle to moderate southerly winds are expected south of the monsoon trough into early next week. Southerly swell will continue to propagate across the region, with a new set of long period SW swell reaching the Galapagos Island tonight into Sun. Light to gentle winds and moderate seas will persist north of the monsoon trough. ...REMAINDER OF THE AREA... Please refer to the Special Features section for details on Tropical Storm Octave, and on Invest EP99 located offshore of SW Mexico with the potential for tropical cyclone formation. Outside of Octave, a surface trough is analyzed over the NW waters and runs from 29N135W to 19N137W. Fresh NE to E winds and rough seas are observed near the northern end of the trough axis due to the pressure gradient between the trough and high pressure to the N of the forecast region. High pressure dominates the remainder of the area N of 20N W of 115W. Moderate to locally fresh southerly winds are south of the monsoon trough W of 110W. Moderate to rough seas are noted within these winds. Elsewhere, moderate or lighter winds and moderate seas prevail. For the forecast, Octave will move to 15.0N 124.1W this evening, 15.5N 124.1W Sun morning, 15.9N 123.5W Sun evening, 16.0N 122.6W Mon morning, 16.0N 121.4W Mon evening, and 15.7N 120.2W Tue morning. Octave will weaken to a tropical depression near 15.2N 118.0W early Wed. The area of NW swell will continue to spread southward and weaken by Sun. Meanwhile, a new set of large southerly swell will reach the equator today. $$ GR