Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Oct 14 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 1800 UTC surface analysis and satellite imagery through 2000 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the SW Caribbean Sea to across southern Nicaragua and the Gulf of Papagayo near 11.5N86W to 1008 mb low pressure, Invest EP91, near 12N92.5W to 12.5N100W to 10N106W to 11N112W to 08N120W to 09N129W. The ITCZ extends from 09N129W to beyond 10N140W. Scattered moderate convection is noted from 01N to 07.5N between the coast of Colombia at 77W and 81W, from 02N to 08N between 82W and 92W, from 08.5N to 16N between 86W and 95W, and from 06N to 15N between 95W and 100W. Similar convection is noted from 09.5N to 12.5N between 137W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A trough extends from SW Arizona southwestward to across the northern Gulf of California while broad high pressure is W of Baja California ahead of a cold front now moving S of 30N. A tight gradient associated to the trough was producing fresh to strong SW winds over the northern Gulf waters per a recent ASCAT scatterometer pass, with locally fresh NW winds behind the trough. Fresh to near gale-force northerly gap winds are ongoing in the Gulf of Tehuantepec with 1008 mb low pressure, Invest EP91, SE of the Gulf along the monsoon trough near 12N92.5W, per recent ASCAT scatterometer data. Seas in the area are 5-8 ft. As mentioned, a cold front is moving S of 30N currently just W of the outer Baja California Norte waters with moderate to fresh SW winds ahead of it. Elsewhere, winds are moderate or weaker under the broad high pressure, locally fresh near Cabo Corrientes and Cabo San Lucas. Seas are 5-7 ft W of 110W and offshore Baja California in NW swell, except building to around 8 ft just ahead of the front, and 4-6 ft elsewhere E of 110W in primarily S-SW swell. In the Gulf of California, seas are 4-6 ft in the northern portion, and 2-3 ft elsewhere. For the forecast, moderate to fresh winds in the northern Gulf of California will linger into Wed as a cold front approaches with troughing ahead of it. Northerly swell will spread through the waters W of Baja California tonight into Wed in the wake of a weakening cold front that will move across Baja California and the Gulf of California. Winds will freshen behind the front offshore Baja California through mid-week as high pres builds in locally strong from near Cabo San Lazaro northward Wed night into early Thu. Winds then will weaken there by the end of the week into the weekend as the gradient slackens. Fresh to strong northerly gap winds will persist in the Gulf of Tehuantepec through at least mid-week. 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... A broad 1008 mb low pressure, Invest EP91, located near the coast of southern Mexico and portions of Central America, is producing a large area of disorganized showers and thunderstorms as described with the monsoon trough/ITCZ section above. Associated winds are moderate to fresh offshore Guatemala and far western El Salvador. Winds are moderate or weaker elsewhere. Seas are 4-6 ft in mixed SW and NW swell across the waters. For the forecast, environmental conditions appear conducive for gradual development of the low pressure area, 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, mainly W of the offshore waters of Guatemala. Winds may freshen S of the monsoon trough as it lifts northward through the remainder of the week, which would build seas slightly. ...REMAINDER OF THE AREA... A cold front has moved S of 30N, extending from 30N121.5W to 29N126.5W to 30N122W, with moderate to fresh NW-N winds behind it. Ahead of and behind the front, associated northerly swell of 8-11 ft is already building into the N-central waters N of 28N between 120W and 135W. A broad ridge is across the waters N of the monsoon trough and ITCZ ahead of the front. Winds across the open waters are mainly moderate or weaker. Seas are mainly 4-7 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 N of 20N through Thu while gradually decaying. Winds will locally freshen behind the front as high pres builds in. Associated northerly swells of 8-11 ft will continue to propagate southward through mid-week before decaying. Farther S, weak low pressure is likely to form along the monsoon trough between 115W and 120W through Thu night. Looking ahead, a reinforcing set of NW swell may arrive by the end of the week into the weekend in the NW and W-central waters keeping seas to rough, with yet another set possibly arriving early next week.