000 AXPZ20 KNHC 012217 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Nov 1 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ...SPECIAL FEATURES... Tropical Storm Pilar is centered near 12.4N 91.7W at 2100 UTC, moving west at 9 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Peak seas are currently around 18 ft. Numerous strong convection has erupted within 60 nm across the NE semicircle, while scattered moderate isolated strong convection is within 45 nm SE and 120 nm NW semicircles. On the forecast track, Pilar will continue to move away from the coast of Central America, turning more west-southwest tonight and reaching near 12.0N 93.4W Thu morning, near 11.1N 96.2W Thu afternoon, near 10.2N 99.4W Fri morning, 9.5N 102.4W Fri afternoon, 9.3N 105.1W Sat morning, and near 9.4N 107.8W Sat afternoon, before weakening to a tropical depression over the open Pacific near 10.0N 111.7W Sun afternoon. Heavy rains from Pilar will begin to shift away from the coasts later tonight. However, those that occur will produce flash and urban flooding, along with mudslides in areas of higher terrain of the Pacific coast of Central America from southern El Salvador to Guatemala. Swell generated by Pilar is expected to continue affecting the Pacific coast of Central America during the next few days, likely causing dangerous surf and life- threatening 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: Storm force N winds continue across the Gulf of Tehuantepec this afternoon and are expected to remain at minimal storm force through early Thu due to a very tight pressure gradient across the region in the wake of a cold front N of the area. Midday altimeter data across the area showed seas downwind of Tehuantepec had already built 16-18 ft. Gales will then continue for the remainder of Thu through early Sun. Very large and dangerous seas of 12-24 ft will build tonight and Thu with these winds, and will merge with swells generated by Pilar located SE of the area, resulting in confused and hazardous seas where they interact. 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 well SW of Pilar near 07N94W to 05N100W to low pressure, Invest EP93, near 12.5N116W to 08N133W. The ITCZ extends from 08N133W to beyond 07.5N140W. Scattered moderate to strong convection is noted from 05N to 08N E of 87W, and within 120 nm either side of trough between 113W and 130W. Scattered moderate isolated strong convection is noted within 120 nm S of the trough between 93W and 98W, and from 08N to 09N W of 137W. ...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 moderate pressure gradient continues over the Gulf of California region, producing fresh to strong NW-N winds in the central and northern Gulf, with moderate to fresh winds in the southern Gulf. Seas are 4-6 ft across the northern Gulf and 3-5 ft across the remainder of the Gulf. Elsewhere across the Baja California offshore waters, a weak ridge prevails across the region, producing mainly light to gentle winds with 4-5 ft seas in mixed SW and NW swell. For the forecast, other than the Gulf of Tehuantepec Storm Warning, Pilar will begin to move west-southwestward tonight through Fri, and pass through the southern portion of the strong winds blasting out of Tehuantepec Thu and Thu night. As Pilar moves into this area, gales occurring downwind of the Gulf of Tehuantepec may briefly spread all the way to the NW quadrant of Pilar. By Thu, a slow and gradual weakening trend is expected into the weekend. Meanwhile, fresh to strong winds in the northern and central Gulf of California will diminish tonight with subsiding seas. Mainly gentle to moderate winds will prevail elsewhere, possibly increasing to fresh to strong from Punta Eugenia northward by early next week. ...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, moderate to locally fresh S-SW monsoonal winds prevail across the offshore waters with seas of 4-6 ft, except 6-8 ft well offshore of El Salvador, where NW swell from the Tehuantepec storm event has arrived. Scattered showers and thunderstorms are across the waters from south of Costa Rica eastward as described above. For the forecast, Pilar will continue to move away from the coast of Central America, turning more west-southwest tonight and reaching near 12.0N 93.4W Thu morning, near 11.1N 96.2W Thu afternoon, near 10.2N 99.4W Fri morning, the move away from the region and gradually weaken through the weekend. In addition to high and confused seas interacting between Pilar and seas generated across Tehuantepec, large and dangerous surf will continue along the coastlines of El Salvador and Guatemala through Fri. Elsewhere, mainly moderate monsoonal winds will prevail through the forecast period. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on Tropical Storm Pilar. High pressure is centered W of central California along 128W with a ridge extending south and southwestward across the waters N of the monsoon trough and ITCZ, and W of 118W. Fresh winds to around 20 kt surround a 1008 mb low pressure, Invest EP93, near 12.5N116W, where seas are 6-7 ft. Winds are moderate or weaker elsewhere, along with seas of 5-7 ft. For the forecast, high pressure N of the area will shift slightly SE through the next few days and act to freshen the winds modestly to the S of 24N and W of 120W through the weekend, which will build seas to around 8 ft in that area. Little change in seas is forecast elsewhere, except in the far NW waters where seas may build to around 8 ft late in the weekend in new NW swell. Pilar will move west-southwestward through the weekend and pass along and S of 10N through Sun, before beginning to turn west-northwestward and weakening to a tropical depression. Meanwhile, the organization of Invest EP93 has not improved since yesterday, and the environmental conditions are forecast to become increasingly unfavorable for development during the next day or two while the low meanders over the central portion of the eastern Pacific basin. Looking ahead, a larger pulse of NW swell may arrive and push SE of 30N140W Mon. $$ Stripling