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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURES... South of Southern Mexico (Invest EP91): Low pressure of 1007 mb is analyzed along the monsoon trough near 12N94W. Scattered moderate to isolated strong convection is within 60 nm SE of the low. This feature is part of a broad area of low pressure that is producing disorganized scattered moderate convection near the coast of southern Mexico and portions of Central America. Environmental conditions appear conducive for gradual development, and a tropical depression could form late this week or over the weekend. This system is expected to move little during the next few days, but a slow northwestward motion near the coast of southern and southwestern Mexico is expected by the weekend. This system has a medium chance of becoming a tropical cyclone during the next 48 hours. 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 to along the coast of central Panama and west-northwestward to across central Costa Rica, and continues northwestward to 11N86W to low pressure, Invest EP91, near 12N94W 1007 mb to 10N103W to 11N113W and 08N121W, where it transitions to the ITCZ to 07N128W to 11N135W and to beyond 11N140W. Scattered moderate to isolated strong convection is seen from 06N to 09N between 94W-101W. ...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 potential for tropical cyclone formation. A trough extends from SW Arizona southwestward to across the northern Gulf of California and to across southern Baja California as broad high pressure ridging remains west of Baja California. A cold front is analyzed from near 30N117W to 28N126W and to near 30N135W. Fresh to near gale-force northerly gap winds are ongoing in the Gulf of Tehuantepec with 1007 mb low pressure, Invest EP91, located to the southeast of the Gulf region along the monsoon trough near 12N94W. Seas over this area 5 to 7 ft. Winds are moderate or lighter under the broad high pressure as noted in the latest scatterometer satellite data passes. Locally fresh northwest winds are near Cabo Corrientes and Cabo San Lucas as seen in an overnight scatterometer satellite data pass. Seas are 5 to 7 ft W of 110W and offshore Baja California in northwest long-period swell, except for higher seas of 7 to 10 ft north of Punta Eugenia. Seas are about 4 to 6 ft E of 110W in primarily south to southwest swell. In the Gulf of California, seas are 3 to 4 ft, except for slightly higher seas of 4 to 5 ft in southwest long- period swell at the entrance to the Gulf. For the forecast, northwest swell moving through the waters west of Baja California will gradually subside through Thu morning. Fresh to strong 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, and a tropical depression could form late this week or over the weekend. This system is expected to move little during the next few days, but a slow northwestward motion near the coast of southern and southwestern Mexico is expected by the weekend. Regardless of development, expect 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 potential for tropical cyclone formation. A 1007 mb low along the monsoon near 12N94W is part of the the Special Features broad area of low pressure. Moderate to fresh east to southeast winds along with seas of 5 to 6 ft are north and north of the low while moderate southeast winds are northeast of the low to the waters near the northwest part of El Salvador and extreme southern Guatemala. Seas are 4 to 6 ft primarily in southwest swell over these waters. For the forecast, in association with the Special Features broad area of low pressure, expect increasing winds and building seas, mainly west 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 slight build up of seas. ...REMAINDER OF THE AREA... A rather fast moving cold front extends from near 30N117W to 26N126W and northwestward to near 30N135W. Overnight scatterometer satellite data passes reveal gentle to moderate northwest to north winds behind the front. A 0230Z Jason-3 altimeter satellite data pass reveals seas of 8 to 11 ft in long-period north swell behind the front. Otherwise, a broad ridge is across the waters north of the monsoon trough and ITCZ ahead of the front. The gradient between the ridge and relatively lower pressures in the ITCZ/Monsoon Trough region is allowing for gentle to moderate winds north 09N and west of about 116W. Seas are mainly 4 to 7 ft away from the northerly swell in a wide variety of mixed swell. For the forecast, the cold front will move southeastward across the waters north of about 20N through Thu while weakening and eventually dissipating. Winds will locally freshen behind the front as high pressure builds in across the area. The seas of 8 to 11 ft in the long-period north swell will continue to press southward through Thu while decaying. Farther south, weak low pressure is likely to form along the monsoon trough between 115W and 1202 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 northwest and west-central portions of the area maintaining seas to a rough state, with yet another set possibly arriving early next week.