Eastern Pacific Tropical Weather Discussion
700 AXPZ20 KNHC 132046 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Sep 13 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 2030 UTC. ...SPECIAL FEATURES... Tropical Storm Norbert is centered near 18.8N 134.0W at 13/2100 UTC, moving west-northwest at 11 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed is 40 kt with gusts to 55 kt. Peak seas are 17 to 18 ft, or 5.5 m. Numerous moderate to scattered strong convection is noted within 120 nm in the NW semicircle of Norbert. Norbert is moving toward the west- northwest, and a west-northwestward to westward motion is expected during the next few days. Some fluctuations in intensity remain possible for the rest of the day, followed by a gradual weakening trend after that. Newly upgraded Tropical Depression Fifteen-E is centered near 17.2N 117.2W at 13/2100 UTC, moving west at 7 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are 8 to 11 ft. Numerous moderate to scattered strong convection is noted within 300 nm in the SE quadrant and 690 nm in the SW quadrant. The depression is moving toward the west. A slightly faster westward to west- southwestward motion is forecast during the couple of days. Some slight strengthening is expected during the next day or two, and the depression is forecast to become a tropical storm tonight or Mon. 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 Lowell NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details on both systems. ...TROPICAL WAVES... A tropical wave is along 99W from 03N to 14N to just offshore and southwest of Oaxaca, Mexico, moving west at around 20 kt. Associated convection is described below in the ITCZ/Monsoon Trough section. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 1007 mb low pressure in the SW Caribbean Sea at 10N77W to 05.5N105.5W to 09N112W, then resumes from 15N119W to 10N128W, then resumes from 16N134W to 11N140W. In addition to the convection associated with T.S. Norbert and T.D Fifteen-E, scattered moderate convection is active from 02N to 12N between 77W and 131W. Similar convection is noted within 120 nm of the coast of Mexico between 93W and 99W, and between 103W and 106W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more information about recently upgraded Tropical Depression Fifteen-E. Fresh N gap winds are across the Gulf of Tehuantepec. Elsewhere, gentle to moderate breezes and 3-6 ft seas prevail across Mexican offshore waters, with 1-3 ft seas in the Gulf of California. For the forecast, Fifteen-E will strengthen to a tropical storm as it moves away from the area to near 17.0N 118.2W Mon morning, then move farther away to 16.7N 119.8W Mon afternoon. Elsewhere, a ridge will build across the offshore waters of Baja California, bringing moderate to locally fresh NW to N winds through the early part of the week. Expect fresh winds across the northern Gulf of California through the early part of the week due to the pressure gradient between the ridge and lower pressure over the Colorado River valley, locally strong Mon night. Winds will freshen again off Baja California by the end of the week, locally strong near Punta Eugenia. Strong to near-gale N gap winds will pulse again in the Tehuantepec region beginning tonight, with building seas of 8 to 10 ft at times. Meanwhile, rough seas will build well offshore Baja California Norte tonight through Mon night. ...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 locally rough seas across the Gulf of Papagayo region, extending downstream to near 90W. Elsewhere, moderate or weaker winds and moderate seas are prevalent, except slight seas offshore Colombia and Panama. Convection continues to develop on either side of the monsoon trough. Gusty winds and higher seas are likely occurring near thunderstorms. For the forecast, the 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 Thu, then pulsing to moderate to fresh thereafter. Moderate to locally fresh N winds may pulse in the Gulf of Panama at night into early Thu. Winds will be moderate or weaker elsewhere along with moderate seas, except locally rough southwest of the Galapagos Islands through Mon, and slight offshore Colombia and eastern Panama. ...REMAINDER OF THE AREA... Please see the Special Features section for more information about Tropical Storm Norbert and recently upgraded Tropical Depression Fifteen-E. Away from the impacts of T.S. Norbert and T.D. Fifteen-E, mainly moderate to fresh winds cover the waters north of 16N and west of 115W. Moderate to fresh SE-S winds and rough seas are found south of 04N between 95W and 130W. Winds are moderate or weaker elsewhere with moderate seas. For the forecast, Norbert will move to 19.2N 136.0W Mon morning, 19.7N 138.6W Mon afternoon, 20.2N 141.4W Tue morning, weaken to a tropical depression near 20.7N 144.0W Tue afternoon, become a remnant low and move to 20.8N 146.9W Wed morning, and dissipate Wed afternoon. Meanwhile, Fifteen-E will strengthen to a tropical storm near 17.0N 118.2W Mon morning, move to 16.7N 119.8W Mon afternoon, 16.5N 121.6W Tue morning, weaken to a tropical depression near 16.4N 123.6W Tue afternoon, 16.3N 125.7W Wed morning, and 16.1N 128.1W Wed afternoon. Fifteen-E will become a remnant low as it moves to 16.0N 133.0W Thu 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 N-central/NE waters through the early part of the week.