000 AXPZ20 KNHC 311635 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Oct 31 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 1200 UTC surface analysis and satellite imagery through 1540 UTC. ...SPECIAL FEATURES... Tropical Storm Pilar is centered near 11.2N 89.9W at 1500 UTC, moving east at 3 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas are currently around 17 ft. Numerous strong convection is from 10N to 13N between 87W and 91.5W. Scattered moderate isolated strong convection is elsewhere from 09.5N to 14.5N between 87W and 93W. Pilar is expected to stall later today, then begin to move west-southwestward Wed through Thu and away from land. Pilar could intensify some over the next day or two before gradual weakening likely begins on Thursday. 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 continue affecting the Pacific coast of Central America during the next few days. 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: Gale force N winds in the Gulf of Tehuantepec are occurring as high pressure surges down across eastern Mexico ahead of a cold front in the Gulf of Mexico. Winds will increase to strong gale later today, then to minimal storm force tonight through early Thu. Winds may fluctuate to just below storm force to minimal storm force at times, but the difference will be negligible. Gales will continue after that through Sat night. Very large and dangerous seas of 12-24 ft will build with these winds, and also mix with swells generated by Pilar located SE of the area, resulting in confused and hazardous seas where they merge. 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 07N92W to 06N102W to low pressure, EP93, near 11.5N116.5W, to 07.5N129W. The ITCZ extends from 07.5N129W to beyond 07N140W. Scattered to locally numerous moderate to strong convection is noted from 01.5N to 09.5N E of 87W, and within 120 nm either side of the trough between 113W and 125W. Scattered moderate isolated strong convection is noted within 180 nm S of the trough between 91W and 108W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on Tropical Storm Pilar, and on a Gulf of Tehuantepec Storm Warning. A very tight pressure gradient is over the Gulf of California region with fresh to strong NW-N winds in the central and northern Gulf, local gusts to gale force in the northern Gulf where overnight ASCAT scatterometer data showed a significant area of 30 kt winds. A recent altimeter pass also sampled max seas of 7-9 ft from 29N to 31N. Moderate to fresh NW-N winds and 5-8 ft seas are in the southern Gulf of California. A couple of ship observations near the entrance to the Gulf showed winds a bit higher although these observations are elevated. Elsewhere across the Baja offshore waters N of Punta Eugenia, gentle to moderate N to NE winds prevail, with some narrow zones of stronger NE winds filtering through passages through Sebastian Vizcaino Bay to around Punta Eugenia. Seas are 5 to 6 ft across these offshore waters. Mainly light to gentle winds are across the remainder of the offshore waters, locally moderate near Cabo Corrientes. For the forecast, other than the Gulf of Tehuantepec Storm Warning, Pilar will stall today, than move west-southwest Wed through Fri and away from land. Large northerly swell that will be generated by this Tehuantepec wind event will merge with swell from Pilar to produce large and confused seas across these southeast Mexican waters through Thu. Meanwhile, fresh to strong winds in the northern and central Gulf of California will diminish Wed while seas also subside. 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. Scattered showers and isolated thunderstorms are across the waters from Colombia northwestward as described above. For the forecast, Pilar will move to 11.5N 89.8W this afternoon, the turn west-southwestward and move to 11.7N 90.2W Wed morning, near 11.1N 93.4W Thu morning, near 9.9N 98.5W Fri morning, then continue west-southwestward through the weekend. Little change in intensity is expected through Thu. Elsewhere, mainly gentle to moderate winds will prevail through the forecast period, except becoming fresh to strong in the Gulf of Panama Thu night into Fri. A storm-force gap wind event in the Gulf of Tehuantepec will generate very large NW swell into the offshore waters of Guatemala today through the end of the week. These seas will combine with those generated by Pilar to create confused and hazardous boating conditions. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on Tropical Storm Pilar. High pressure is centered offshore of central California and extends a ridge across the waters N of the monsoon trough. Fresh SW winds are across the SE side of 1008 mb low pressure, Invest EP93, which is near 11.5N116.5W, along with seas of around 9 ft as sampled by recent altimeter data. Gentle to moderate winds are found elsewhere across the open waters, along with 5-7 ft seas. For the forecast, Pilar will begin to move west-southwestward and away from land Wed through Thu, reaching near 11.1N 93.4W Thu morning, near 9.9N 98.5W Fri morning, then continue west- southwestward through the weekend. Meanwhile, Invest EP93 has not become any better organized since yesterday, and environmental conditions are forecast to become increasingly unfavorable for development during the next couple of days while the low drifts generally northeastward. Elsewhere, gentle to moderate winds will prevail, increasing to moderate to fresh from 09N to 21N W of 110W by the end of the week into the weekend, which may build seas to around 8 ft in that area. Little change in seas is forecast elsewhere. $$ Stripling