Tropical Weather Discussion
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Issued by NWS
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970 AXPZ20 KNHC 122131 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Sep 12 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Norbert is centered near 17.6N 129.6W at 12/2100 UTC, moving west-northwest at 10 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas are 20 ft within 150 nm N semicircle of the center. Numerous moderate to scattered strong convection is noted within 150 nm NW semicircle. Norbert is moving toward the west- northwest. A turn toward the west is forecast on Sunday, and Norbert should continue in this direction during the next several days. Only modest strengthening is expected through the weekend. By early next week, a gradual weakening trend is expected to commence, and Norbert should degenerate into a post- tropical remnant low toward the end of next week. Please read the latest High Seas Forecast issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Fourteen-E NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gale Warning south of Clarion Island (Invest EP97): Showers and thunderstorms associated with an area of low pressure located several hundred miles southwest of the southwestern coast of Mexico have become a little less organized this morning. Environmental conditions appear conducive for development, however, and a tropical depression is expected to form during the next couple of days while it moves generally west-northwestward to westward over the central and western portions of the eastern Pacific basin. This system has a high chance of tropical cyclone formation within the next 48 hours. A Gale Warning is in effect with this system. Regardless of tropical cyclone development, winds strong winds with rough seas are expected to the south and southwest of Clarion Island through Mon. Refer to the latest NHC Tropical Weather Outlook at website - www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 91W north of 03N extending into Guatemala, moving west at 10 to 15 kt. Scattered moderate to isolated strong convection is active from 04N to 12N between 83W and 98W. A tropical wave is along 114W from 07N to 20N, moving westward at 10 to 15 kt. A 1008 mb surface low (EP97) is along the wave axis near 17N114W. A well defined swirl of low clouds is evident in visible satellite imagery in association with this low. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 05N100W to 16N115W to 11N110W, and from 12N130W to beyond 13N140W. In addition to the convection associated with T.S. Norbert and Invest EP97, scattered moderate convection is found from 04N to 12N between 83W and 98W, from 07N to 11N between 105W and 112W, and from 07N to 14N between 117W and 125W. Scattered moderate to isolated strong is noted from 04N to 10N W of 130W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more information about Tropical Storm Norbert and Invest EP97. Recent scatterometer satellite pass indicates fresh to strong winds within 90 nm on the E semicircle of Invest EP97, that is a 1008 mb low pressure, located south of Clarion Island near 17N114W. Moderate to locally rough seas accompany these winds. Scatterometer data also show moderate to locally fresh NW winds off the coast of SW Mexico. Similar winds speeds are also noted over the northern Gulf of California. Light to gentle winds and moderate seas dominate the offshore forecast waters of Baja California. For the forecast, away from the impacts of T.S. Norbert and Invest EP97, a ridge will build across the offshore waters of Baja California, bringing moderate to locally fresh NW to N winds Sun into early next week. Expect fresh winds across the northern Gulf of California early next week due to the pressure gradient between the ridge and lower pressure over the Colorado River valley. Looking ahead, fresh to strong N to NE gap winds will pulse again in the Tehuantepec region by the middle of next week, building seas to 8 or 9 ft. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure north of the area is promoting fresh to strong easterly trade winds and rough seas across the Gulf of Papagayo region, extending downstream to near 90W. Elsewhere, moderate or weaker winds and moderate seas are prevalent. Convection continues to develop on either side of the monsoon trough. Gusty winds and higher seas are likely occurring near thunderstorms. For the forecast, a ridge north of the area will continue to support pulsing fresh to strong easterly winds and moderate to rough seas across the Papagayo region through early next week. Meanwhile, gentle to moderate southerly winds and moderate seas are expected over the waters between Ecuador and the Galapagos through at least the middle of next week. Moderate or lighter winds and moderate seas in long period SW swell are forecast elsewhere. ...REMAINDER OF THE AREA... Please see the Special Features section for more information about Tropical Storm Norbert and Invest EP97. Away from the impacts of T.S. Norbert, moderate to locally fresh SE winds and rough seas are found south of 04N and west of the Galapagos Islands to about 135W. A 1020 mb high pressure located N of area near 34N133W dominates the waters north of 20N. Under the influence of this system, and away from Norbert, mainly moderate winds and moderate seas prevail, with the exception of light to gentle winds north of 20N and east of 116W to Baja California Peninsula. For the forecast, Tropical Storm Norbert will move to 18.0N 131.1W Sun morning, 18.5N 133.2W Sun afternoon, 18.8N 135.4W Mon morning, 19.1N 138.0W Mon afternoon, 19.3N 140.7W Tue morning, and weaken to a tropical depression near 19.3N 143.4W Tue afternoon. Norbert will become a remnant low well W of area to near 18.5N 149.0W Wed afternoon. Elsewhere, a cross equatorial swell will persist over the next several days producing seas to 9 ft south of 04N. A tight pressure gradient will result in locally fresh N winds and rough seas in the NE waters late this weekend into early next week. $$ GR