Eastern Pacific Tropical Weather Discussion
330 AXPZ20 KNHC 131607 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Oct 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Hurricane Simon is centered near 20.3N 107.3W at 1500 UTC, moving west at 2 kt. Estimated minimum central pressure is 977 mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt. Peak seas are near 22 ft. Numerous moderate to strong convection is within 45 nm of the center. Scattered to numerous moderate and isolated strong convection is elsewhere from 18.5N to 21N between 109W and 109W. Simon is located further south than estimated overnight, and is now expected to move slowly W to SW through Thu before beginning a northward motion. Simon could approach the coast of western Mexico this weekend. Interests in west-central Mexico and Baja California Sur should continue to closely monitor the latest updates to Simon's forecast. Changes to watches and warnings could be required later today based on the latest forecast trends. Associated heavy rainfall will produce life- threatening flooding and mudslides or worsen any on- going flooding, especially in areas of steep terrain. Swells generated by Simon will affect portions of the coast of southwestern and west- central Mexico during the next few days, as well as the southern Gulf of California. These swells are likely to cause large and powerful surf and life- threatening rip current conditions. Please consult products from your local weather office. Tropical Depression Twenty-One-E has formed this morning several hundred miles south of Oaxaca, Mexico, near 09.8N 96.5W at 1500 UTC, moving northwest at 9 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind is 30 kt with gusts to 40 kt. Peak seas are estimated at 12 ft across the N semicircle. Scattered to numerous moderate to strong convection is occurring from 09N to 13.5N between 92W and 99W. A west-northwestward to northwestward motion should continue over the next 36 hours, then a decrease in forward speed is expected after 48 hours. Tropical Depression 21-E could potentially be very close to the coast of Mexico as a hurricane over the weekend. Extremely favorable oceanic and atmospheric conditions are forecast for at least the next 3 to 4 days, and steady to rapid strengthening is forecast, with a major hurricane possible by Sat. 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 Simon and T.D. Twenty-One-E NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10.5N75.5W to 08N81W to T.D. Twenty-One-E near near 09.8N 96.5W to 05.5N107W. The ITCZ extends from 05.5N107W to 03.5N121W to beyond 06.5N140W. Scattered moderate isolated strong convection is noted from 01.5N to 09N E of 89W, and from 02.5N to 06.5N between 93W and 97W. Scattered moderate to strong convection is noted from 01N to 06N between 101W and 128W and from 05.5N to 09.5N W of 139W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for information on Hurricane Simon, and newly formed Tropical Depression Twenty- One-E. Aside from conditions associated with Simon, which is small in size, mainly gentle to moderate winds prevail across the waters between 20N and a stationary front extending from central Baja 10 22N120W. Moderate to locally fresh N to NE winds are within 150 nm N of the front over the Baja offshore waters, with fresh winds on either side of the front in the far northern Gulf of California. Seas are 7 to 9 ft in NW swell across the Pacific water behind the front and 3 to 5 ft in the northern Gulf. Elsewhere, fresh northerly winds are funneling through the Gulf of Tehuantepec in response to Tropical Depression Twenty- One-E. Gentle to moderate winds, and moderate to rough seas in merging SW and NW swell dominate the remainder of the discussion waters. For the forecast, Hurricane Simon is near 20.3N 107.3W at 8 AM, moving west at 2 kt. Estimated minimum central pressure is 977 mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt. Simon will move slowly W to SW through Thu, reaching near 20.3N 107.8W Wed morning, near 20.1N 107.7W Thu morning, then begin to move northward, reaching near 21.0N 107.8W Thu afternoon, near 22.8N 108.2W Fri morning, near 25.2N 109.6W Sat morning and then inland near 28.5N 110.5W by Sun morning. A stationary front drifting across the northern waters will gradually dissipate late today. Rough seas in NW swell west of Baja California will gradually diminish through early Wed. Elsewhere, Tropical Depression Twenty-One-E has formed near 09.8N 96.5W at 8 AM, moving NW at 9 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind is 30 kt with gusts to 40 kt. A west- northwest to northwestward motion should continue over the next 36 hours, then a decrease in forward speed is expected after 48 hours. Steady to rapid strengthening is forecast, with a major hurricane offshore of SW Mexico possible by Sat. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Easterly gap winds downstream of the Papagayo region have diminished to moderate in recent hours, as newly formed Tropical Depression Twenty-One-E is passing S of Tehuantepec along about 10N. Fresh to strong winds and rough seas to 10 ft are found across the NE semicircle of Twenty-One-E, and dominate the outer offshore waters to the southwest of Guatemala and El Salvador. Scattered to numerous showers and thunderstorms also prevail across these outer waters. Gentle to moderate winds, and moderate to locally rough seas, prevail over the remainder of the offshore waters. Scattered moderate convection continues this morning across the waters of Panama and Colombia E of 82W. For the forecast, fresh to strong winds and rough seas, associated with Twenty-One-E, well offshore Guatemala and El Salvador will decrease through Wed as it moves further from the area and intensifies. Otherwise, a weak pressure gradient will support moderate or lighter winds, and moderate seas dominated by SW swell across much of the forecast waters through the end of the week. Scattered showers and thunderstorms are expected to remain active across the waters E of 85W today. ...REMAINDER OF THE AREA... A stationary front extends across the NE waters from Baja California Norte to 20N125W. Moderate to fresh N to NE winds and rough seas of 7 to 10 ft in NW swell cover the waters N of 20N behind the front. Light to gentle winds and seas of 6 to 8 ft in merging NW and SW swell generally prevail elsewhere S of 20N W of 120W, except for moderate SE to S winds near the equator. For the forecast, the stationary front will gradually dissipate through this evening. Large SW swell will affect the waters S of the Equator and west of 105W over the next couple of days, followed by another pulse of large S-SW swell arriving into the waters W of 100W Wed night.