000 AXPZ20 KNHC 300840 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Oct 30 2023 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 0730 UTC. ...SPECIAL FEATURES... Tropical Storm Pilar is centered near 11.0N 91.8W at 30/0900 UTC, moving east-northeast at 3 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are currently around 12 ft. Numerous moderate isolated strong convection is within 30 nm in the SE semicircle and 75 nm in the NW semicircle of Pilar. Scattered moderate isolated strong convection is elsewhere within 16N94W to 07N79W to 04N84W to 08N96W to 16N94W. A continued slow east- northeastward motion is expected during the next day or two. On the forecast track, Pilar could be near the coast of El Salvador Tuesday through early Wednesday, though the core of the system is expected to remain offshore. Strengthening is expected during the next day or so, and Pilar could be near hurricane strength on Tuesday. Weakening is expected to begin by Wednesday. Heavy rains from Pilar will produce flash and urban flooding, along with mudslides in areas of higher terrain of the Pacific coast of Central America from El Salvador southward to Costa Rica through Wednesday. Swells generated by Pilar are expected to reach portions of the Pacific coast of Central America later today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. 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 Pilar NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gulf of Tehuantepec Storm Warning: Fresh to strong N winds were measured by an earlier ASCAT scatterometer pass, and are now likely slightly lower. That will be short lived as fresh to strong winds will return around sunrise, then increase to gale force this evening as strong high pressure surges down the eastern slopes of Mexico out ahead of a cold front. Winds will increase to strong gale during the day Tue, then to minimal storm force Tue evening through early Thu. Winds may fluctuate to just below storm force to minimal storm force at times, but the difference will be negligible. While storm force winds are forecast to diminish by Thu afternoon, gale force winds are forecast to continue through the end of the work week. Very large and dangerous seas are forecast with this event, building to 12-22 ft across a large area downwind of the immediate Gulf of Tehuantepec during the strongest winds. These seas will also mix with swell generated by Tropical Storm Pilar off to SE resulting in confused seas where they meet. Please read the latest NHC High Seas forecast at www.hurricanes.gov/marine for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from SW of Pilar near 09N94W to low pressure, EP93, near 10N118W to 06N126W to 06N140W. Scattered moderate isolated strong convection is noted within 150 nm SE-S of the monsoon trough between 112W and 133W. Scattered moderate convection is noted from 05N to 08N between 93W and 112W, and from 03.4S to 01N between Ecuador and 85W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on Tropical Storm Pilar, and on a recently upgraded Gulf of Tehuantepec Storm Warning. A cold front is moving through NW Mexico and high pressure is surging down across the Rocky Mountain United States. A tight pressure gradient is supporting fresh to strong winds in the Gulf of California W of 111W. Remnant seas from presumed earlier gale force winds are 8-10 ft as measured by a rare altimeter pass in that area. Moderate to fresh NW-N winds are offshore Baja California in the vicinity of Punta Eugenia with locally strong winds in Sebastian Vizcaino Bay filtering through Baja California Norte passage from the Gulf of California. Seas downwind of Punta Eugenia are 7-8 ft as sampled by a recent altimeter pass. Mainly gentle to moderate winds and 4-6 ft seas are elsewhere. For the forecast, other than the Gulf of Tehuantepec Storm Warning, Pilar will move to 11.1N 91.2W this afternoon, 11.6N 90.1W Tue morning, 12.0N 89.5W Tue afternoon, 12.0N 89.2W Wed morning, 11.7N 89.7W Wed afternoon, and 11.1N 91.2W Thu morning. Pilar will change little in intensity as it moves to 9.8N 95.3W early Fri. Fresh to strong winds in the northern and central Gulf of California will diminish by Wed afternoon while seas also subside. Moderate to occasionally fresh winds will prevail west of Baja California near Punta Eugenia through this morning while seas downwind diminish. Mainly gentle to moderate winds will prevail elsewhere, along with 4-6 ft seas. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please refer to the Special Features section above for details on Tropical Storm Pilar. Aside from Pilar, mainly moderate S-SW winds are across the offshore waters with seas of 5-7 ft, except 4-6 ft offshore Colombia. Numerous showers and scattered thunderstorms are across the waters from Panama northwestward as described above, with some convection noted offshore Ecuador as well. For the forecast, Pilar will move to 11.1N 91.2W this afternoon, 11.6N 90.1W Tue morning, 12.0N 89.5W Tue afternoon, 12.0N 89.2W Wed morning, 11.7N 89.7W Wed afternoon, and 11.1N 91.2W Thu morning. Pilar will change little in intensity as it moves to 9.8N 95.3W early Fri. Elsewhere, mainly gentle to moderate winds will prevail through the forecast period, except becoming fresh in the Gulf of Panama by the end of the week. A storm force gap wind event in the Gulf of Tehuantepec will generate and send very large and dangerous seas offshore Guatemala Tue through the end of the week. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on Tropical Storm Pilar. High pressure of 1024 mb is located near 32N137W and prevails across the waters N of the monsoon trough. Moderate to locally fresh trades are noted from 10N to 24N and W of 120W, along with 6-8 ft seas. Gentle to moderate winds and 5-7 ft prevail across the remainder of the waters, except 4-6 ft N of 24N and W of 132W closer to the high. Meanwhile, an 1010 mb area of low pressure located more than 1000 nautical miles south-southwest of the southern tip of the Baja California peninsula near 10N118W is producing disorganized shower activity and fresh winds per a recent ASCAT scatterometer pass. For the forecast, Pilar will move to 11.1N 91.2W this afternoon, 11.6N 90.1W Tue morning, 12.0N 89.5W Tue afternoon, 12.0N 89.2W Wed morning, 11.7N 89.7W Wed afternoon, and 11.1N 91.2W Thu morning. Pilar will change little in intensity as it moves to 9.8N 95.3W early Fri. Moderate to occasionally fresh trade winds and seas to 8 ft will persist in the trade wind region west of 130W through today, returning by the end of the week. Meanwhile, environmental conditions are marginally conducive for slow development of EP93 during the next couple of days while the low drifts generally northeastward. By the middle of the week, upper-level winds are forecast to become less conducive for additional development. $$ Lewitsky