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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Oct 15 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... South of Southern Mexico (Invest EP91): A broad 1007 mb area of low pressure near 12.5N94.5W is producing some disorganized showers and thunderstorms offshore of southern Mexico and portions of Central America. Scattered moderate isolated strong convection is noted within 180 nm in the NE semicircle. Some fresh to near gale-force winds are nearby, but associated with a plume of gap winds from the Gulf of Tehuantepec where seas are also 7-9 ft. Environmental conditions appear conducive for gradual development of this disturbance, and a tropical depression could form late this week or over the weekend. The system is expected to move little during the next couple of days, but a slow northwestward motion near the coast of southern and southwestern Mexico is expected by the weekend. Regardless of development, expect the potential for increasing winds and building seas. This system has a medium chance of tropical cyclone formation within 48 hours and 7 days. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 10N75.5W to across the SW Caribbean Sea and southern Nicaragua to the Pacific coast near 11.5N86.5W to 1007 mb low pressure, Invest EP91, near 12.5N94.5W to 10N100W to 12N110W to 06N123W to 11N140W. Isolated to widely scattered moderate convection is noted from 02N to 09N between 77W and 90.5W, and from 05N to 15N between 96W and 106W. Similar convection is near the coast of SW Mexico within 180 nm of shore between 100W and 106W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section above for information on a broad area of low pressure, Invest EP91, that is near the coast of southern Mexico with the potential for tropical cyclone formation. A weakening cold front extends from SW Arizona to across Baja California Norte near 32.5N114.5W to offshore and 25.5N123.5W continuing to 27.5N138W. Broad high pressure is building in the wake of the front. NW-N moderate to locally fresh winds are found even out ahead of the front as the high bridges across, with these winds W of 109W or so. Associated NW swells are arriving offshore Baja California Norte with seas of 7-10 ft there. Seas are 5-7 ft elsewhere W of 109W. Fresh to near gale-force N-NE winds are in and downwind of the Gulf of Tehuantepec with seas of 6-9 ft. Mainly light to gentle winds and 4-6 ft are elsewhere, with seas of 2-4 ft in the Gulf of California. For the forecast, NW swell moving through the waters west of Baja California will gradually subside through Thu morning. Fresh to strong, locally near gale-force today, northerly gap winds will persist in the Gulf of Tehuantepec through early Thu afternoon. Meanwhile, a broad area of low pressure, Invest EP91, is near the coast of southern Mexico. Environmental conditions appear conducive for gradual development of this disturbance, and a tropical depression could form late this week or over the weekend. The system is expected to move little during the next couple of days, but a slow northwestward motion near the coast of southern and southwestern Mexico is expected by the weekend. Regardless of development, expect the potential for increasing winds and building seas. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please read the Special Features section above for information on a broad area of low pressure, Invest EP91, that is near portions of the coast of Central America, with the potential for tropical cyclone formation. Otherwise, gentle to moderate winds prevail across the offshore waters, except gentle nearshore from Panama to Nicaragua. Seas are 4-6 ft in mixed swells. Active convection is noted across the waters as described above with locally higher winds and seas possible. For the forecast, in association with the Special Features broad area of low pressure, expect increasing winds and building seas, mainly W of the offshore waters of Guatemala. Winds may freshen south of the monsoon trough as it lifts northward through the remainder of the week, which could lead to a slight build up of seas. Expect tranquil marine conditions across the waters late in the weekend into early next week. ...REMAINDER OF THE AREA... A weakening cold front extends from SW Arizona to across Baja California Norte near 32.5N114.5W to offshore and 25.5N123.5W continuing to 27.5N138W. Broad high pressure is building in the wake of the front. Moderate to locally fresh winds are found behind the front, with gentle to moderate winds elsewhere N of the monsoon trough and ITCZ. Winds are moderate S of the monsoon trough and ITCZ, except to fresh E of 110W to the S of the axis and N of 04N. For seas, northerly swell of 7-11 ft associated with the front are found N of 24N, with 5-7 ft seas in mixed swells S of 24N and W of 110W. Seas are slightly lower overall to the E of 110W. For the forecast, the cold front will gradually decay to a remnant frontal trough by early Thu, then dissipate by the end of the week. Winds will locally freshen behind the front as high pressure builds in across the area. Rough northerly swell in the northern waters will continue to press southward through Thu while decaying. Farther S, weak low pressure is likely to form along the monsoon trough between 115W and 120W through Thu night as depicted in the global models. Looking ahead, a reinforcing set of long-period northwest swell may arrive by the end of the week into the weekend over the NW and W-central portions of the area maintaining seas to a rough state, with yet another set possibly arriving early next week.