Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Sep 18 2026 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 0000 UTC surface analysis and satellite imagery through 0350 UTC. ...SPECIAL FEATURES... A tropical wave extends from 07N to 17N with axis near 116W with low pressure of 1008 mb near 12N116W. The wave is moving westward at about 10 kt. Satellite imagery reveals scattered moderate to strong convection from 08N to 15N between 110W and 123W. Environmental conditions appear conducive for additional development of this system, and a tropical depression is likely to form this weekend as it moves westward at 10 to 15 kt across the western part of the East Pacific and into the central Pacific basin. There is a medium formation chance through 48 hours and high formation chance through 7 days. Please refer to the latest NHC Tropical Weather Outlook at website: www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave extends from 05N to 17N with axis near 100W, moving westward at around 10 to 15 kt. Numerous moderate to isolated strong convection is seen from 03N to 16N between 97W and 109W. The environmental conditions of the tropical wave, which is moving across the Guerrero, Mexico offshores is conducive for gradual development of this system, and a tropical depression is likely to form late this weekend or early next week while it moves gradually northwestward and then northward off the coast of southwestern Mexico. There is a low formation chance through 48 hours and high formation chance through 7 days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N83W to 07N1O3W to 13N123W. Aside from the convection associated with the tropical waves and former TD15-E, numerous moderate to strong convection is from 02N to 09N between 81W and 95W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a ridge over the Gulf of America and the eastern extension of the Pacific monsoon is supporting strong to near-gale force N to NE gap winds across the Gulf of Tehuantepec as indicated by recent scatterometer data. Seas are 8 to 9 ft. A tropical wave moving across the Guerrero offshore waters is producing disorganized showers and thunderstorms over that region. Surface ridging west of the Baja California offshores is supporting moderate to fresh NW winds N of Cabo San Lazaro. Moderate or weaker winds are elsewhere along with moderate seas, except for slight seas in the Gulf of California. For the forecast, winds will continue to pulse in Tehuantepec at fresh to strong speeds through Sat morning, with seas lowering to 6 ft. The environmental conditions of the tropical wave moving across the Guerrero offshores is conducive for gradual development of this system, and a tropical depression is likely to form late this weekend or early next week while it moves gradually northwestward and then northward off the coast of southwestern Mexico. Otherwise, moderate to fresh NW winds will persist along the Baja Peninsula offshores, reaching strong speeds at night Fri and Mon. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent scatterometer data show fresh to strong NE to E winds across the Gulf of Papagayo extending downstream to near 89W. Scatterometer data show moderate or weaker winds elsewhere, except for fresh to strong N winds in the Gulf of Panama extending to about 07N. Altimeter data reveal moderate seas across the majority of the region. For the forecast, the pressure gradient between a ridge north of the area and the eastern north Pacific monsoon trough will support pulsing fresh to occasionally strong easterly winds and moderate to rough seas across the Papagayo into Fri, then pulsing to moderate to fresh thereafter. Moderate winds and seas will prevail elsewhere. ...REMAINDER OF THE AREA... The 1006 mb remnant low of Tropical Depression Fifteen-E is located near 16N133W. Fresh to strong northeast winds are over the waters to the northwest of the low pressure. Seas are 7 to 10 ft with these winds. Satellite imagery shows scattered moderate convection from 08N to 20N between 123 W and 139W. Fresh to strong winds and rough seas supported by the pressure gradient between the area of low pressure and the subtropical ridge north of the area, cover the waters from 15N to 25N west of 125W. Gentle to moderate winds and 4 to 6 ft combined seas in mixed swell are noted elsewhere. For the forecast, see the Special Features and the Tropical Waves Section. Otherwise, environmental conditions appear only marginally conducive for some development of the remnants of TD 15-E as it moves gradually westward, remaining east-southeast of the Hawaiian Islands.