Tropical Weather Discussion
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Issued by NWS
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104 AXPZ20 KNHC 090920 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Nov 9 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Fresh to strong N gap winds will develop across the Gulf of Tehuantepec Sun afternoon before winds quickly strengthen to gale force late Sun night, as a strong cold front moves through the Gulf of America with strong high pressure building across eastern Mexico in its wake. This event is expected to produce a very large area of gale-force winds extending south and southwestward of Tehuantepec to near 12N98W by late Mon night, producing an extensive area of very rough seas of 12 to 20 ft. Gale-force winds will continue across Tehuantepec into early Wed morning, then diminish slightly, with winds pulsing to near 30 kt each night thereafter through early Fri morning. Large NW swell across the northwestern waters: A cold front has entered the far NW waters of the discussion area tonight, and extends from 30N137W to beyond 27.5N140W. This front is connected to a deep low pressure center over the NE Pacific waters near 47N139W. Storm-force NW to N winds have been occurring west of the low, and generating large swell of 20 ft and greater. The front will drift to the southeast Sun before weak low pressure develops along it, then meanders in the vicinity of 28N140W through Tue before dissipating. Large NW swell generated NW of the area has begun to move into the far NW waters tonight, and will build seas to 8 to 14 ft there by morning. The area of seas 12 ft and greater is then expected to spread southeastward from 30N133W to 24N140W by around midnight Sun night before slowly diminishing below 12 ft Mon night. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10.5N75W to 08N92W to 12N108W to 09.5N122W to 10N131W to beyond 09N140W. Scattered moderate isolated strong convection is noted from 05N to 08.5N east of 81.5W, from 09N to 15.5N between 108W and 115W, and from 08.5N to 13N between 119W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough extends from 1013 mb low pres offshore of Baja California Norte near 32N120W to 23N122W, while a second surface trough extends along the eastern shoreline of the Gulf of California to Las Tres Marias. The weak pressure gradient between these features is yielding light to gentle winds across the Baja offshore waters, except moderate N to NE winds from Cabo San Lazaro southward to 20N. Light and variable winds are also noted inside the Gulf of California, becoming gentle N winds from the entrance of the Gulf to the waters near Cabo Corrientes. NW swell continues to slowly subside across the Baja waters tonight. However satellite altimeter data from around midnight continued to show seas of 8 to 11 ft offshore of Baja Norte. Elsewhere south of Punta Eugenia to the Revillagigedo Islands, seas are generally 7 to 10 ft. Seas are 3 ft or less inside the Gulf. Light to gentle NW to W winds continue elsewhere across the Mexican waters to the Gulf of Tehuantepec. Seas across these waters are 4 to 7 ft in mixed NW and SW swell, except to 8 ft offshore of Cabo Corrientes. For the forecast, rough seas in NW swell will gradually subside from N to S across the Baja California waters and offshore of southwestern Mexico through late Sun night, diminishing to less than 8 ft on Mon. Elsewhere, fresh to strong N gap winds will develop in the Gulf of Tehuantepec on Sun afternoon before winds quickly strengthening to gale force late Sun night, as a strong cold front moves through the Gulf of America with strong high pressure building across eastern Mexico in its wake. This gale event is expected to produce a very large area of gale- force winds extending south and southwestward of Tehuantepec to near 12N98W by late Mon night, producing an extensive area of very rough seas of 12 to 20 ft. Gale-force winds will continue across Tehuantepec into early Wed morning, then diminish slightly, with winds pulsing to near 30 kt each night thereafter through early Fri morning. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate NE winds continue across the Papagayo region, as a surface trough prevails in the western Caribbean. Gentle offshore winds prevail elsewhere north of the monsoon trough, along about 10N, with gentle to moderate S to SW winds noted in recent satellite scatterometer data to the south of the trough. Seas of 4 to 5 ft in mixed NW and S swell are occurring over the regional waters, with 6-7 ft seas noted southwest of the Galapagos Islands. Scattered showers and isolated thunderstorms are along the NW coast of Colombia and spread westward into the Gulf of Panama and the SW Panama coastal waters. For the forecast, moderate NE gap winds will pulse to fresh at night across the Papagayo region through early Tue, then increase to fresh to strong throughout the remainder of the week, as a strong cold front moves into the NW Caribbean, with strong high pressure building in the wake of the front. Fresh N winds may briefly occur in the Gulf of Fonseca and offshore of El Salvador Tue night. Farther west, moderate to fresh N to NE winds and high seas are expected offshore of Guatemala Mon night through early Wed as a significant gale-force gap wind event occurs across the Gulf of Tehuantepec region. ...REMAINDER OF THE AREA... A 1018 mb surface high is centered north of the area near 35N127W, and extends a weak ridge southward across the northern waters north of 20N between 120W and 140W. A cold front has entered the NW waters tonight, and extends from 30N137W to beyond 27.5N140W, stemming from a strong complex low pressure system centered near 47N139W. The increasing pressure gradient between the ridge and the front is leading to fresh SW winds north of 26N and west of 135W. Scattered moderate convection is occurring along and within 120 nm behind the front. Recent altimeter and SOFAR buoy data show 8 to 12 ft seas in this region. To the east, a surface trough extends from offshore of southern California to 23N122W, with moderate N winds occurring west of the trough to 125W and north of 28N. Seas remain 8 to 10 ft across this area. Farther south, the pressure gradient between the ridge and the monsoon trough is producing moderate to locally fresh trade winds north of the monsoon trough to 19N. Moderate to fresh S to SE winds are noted to the south of the trough. Widespread rough seas of 8 to 11 ft continue over much of the eastern Pacific waters W of 105W, with NW swell dominating north of 10N, and mixed NW and SW swell farther south. For the forecast, widespread rough seas in NW swell will slowly subside north of 20N through Mon, except for the far northwest waters, and south of 20N through early next week. A cold front across the northwestern waters tonight will meander across the area through Tue, with fresh SW winds occurring north of 25N and west of 135W ahead of the front Sun. A complex low pressure system will evolve over these NW waters early next week, leading to fresh to strong winds surrounding the low. New NW swell will propagate southeastward in this area tonight through early next week, with rough seas expected north of 20N and west of 130W by late Sun, and north of 12N and west of 120W by late Mon. Seas in excess of 12 ft are expected to cover the area from 30N133W to 24N140W through late sun night then slowly diminish into Tue. Looking ahead, strong E to NE winds and rough seas generated by a gale force gap wind event in the Gulf of Tehuantepec will spread large NE swell into the waters from 05N to 15N and east of 110W Mon night through Wed before diminishing. $$ Stripling