013 AXPZ20 KNHC 042115 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Nov 4 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 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Pilar is centered near 10.4N 110.5W at 04/2100 UTC, moving west at 14 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous moderate to strong convection is noted within 90 NW semicircle of center. Scattered moderate to isolated strong convection is elsewhere from 08N to 11N between 108W and 112W, and from 11N to 14N between 105W and 112W. Peak seas are currently around 16 ft. Pilar is moving toward the west near 16 and this general motion is expected to continue through Sunday. A slower forward motion toward the west-northwest or northwest is forecast early next week. Small intensity fluctuations are possible during the next day or so. Steady weakening is forecast early next week. 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 Gale Warning: A recent scatterometer pass provides observations of gale force winds across the Tehuantepec region and downwind to about 14N. A plume of fresh to strong northerly winds extend farther south to near 11N99W. The gales are due to cooler, drier air and high pressure over the Gulf of Mexico, and lower pressure farther south into the tropical Pacific. Seas are likely reaching 16 ft downstream in the Gulf of Tehuantepec, with seas in excess of 8 ft extending beyond 400 nm offshore. This gap wind event will diminish below gale force Sun night into early Mon morning, but fresh to strong gap winds and rough seas will persist until Tue. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Potential for heavy rainfall over Central America: Satellite data and surface observations indicate that the low pressure system over the western Caribbean Sea is now located just off the coast of Costa Rica and Nicaragua. The associated showers and thunderstorms have become less organized during the past few hours, and development of this system appears unlikely before it moves inland over Central America tonight or early Sunday. Regardless of development, this system is expected to bring heavy rains to portions of Central America during the next couple of days. This rainfall could produce flash flooding, along with mudslides in higher terrain areas. Refer to the local weather services for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N86W to 09N104W then continues SW of Pilar from 06N113W to a 1012 mb low pres located near 09N126W to 09N132W. The ITCZ extends from 09N132W to beyond 07N140W. Scattered moderate convection is from 06N to 09N between 83W and 88W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on the Gulf of Tehuantepec Gale Warning. Outside of the Gulf of Tehuantepec gap wind event, a ridge extends across the Baja California offshore waters from a 1021 mb high pres located near 28N133W. The pressure gradient between this system and a meandering trough over the Gulf of California supports gentle to moderate NW to N winds across the waters W of the Baja California peninsula with the exception of moderate to fresh winds in the vicinity of Punta Eugenia. Seas are generally in the 3 to 5 ft range. In the Gulf of California, satellite derived wind data indicate moderate to fresh northerly winds in the N part of the Gulf while gentle to moderate winds prevail elsewhere. Seas are 2 to 3 ft, except 3 to 4 ft near the entrance to the Gulf. Meanwhile, light to gentle winds are noted across the rest of the Mexico offshore waters. Seas range 4 to 6 ft in mixed swell. For the forecast, the gale force winds in the Tehuantepec region are expected to persist into early Mon morning. Rough seas generated by this gap wind event will continue to propagate over the waters off eastern Oaxaca and western Chiapas into Mon. The winds and seas will continue to gradually diminish into Tue off southern Mexico. Looking ahead, a weakening cold front will approach Baja California Norte on Tue followed by fresh NW to N winds and moderate to rough seas. These marine conditions will reach the waters N of Punta Eugenia Tue night into Wed. Seas are forecast to propagate across the waters N of Cabo San Lazaro later on Wed. At the same time, high pressure situated over the Great Basin of the United States will bring moderate to fresh northerly winds across the Gulf of California Wed through Thu night. Seas are forecast to build to 4 to 7 ft within these winds. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate S-SW monsoonal winds prevail across the offshore waters with seas 4 to 6 ft. Seas range 8 to 9 ft across the offshore waters of Guatemala W of 93W due to the Tehuantepec gap wind event. For the forecast, expect large seas off Guatemala through Sun night due to swell generated in the Tehuantepec region by gale force winds. Seas are forecast to peak 10 or 11 ft tonight and Sun. Gentle to moderate winds and slight to moderate seas, primarily in SW swell, will persist elsewhere. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on Tropical Storm Pilar. A ridge extends across the region north of 20N anchored by a 1021 mb high pressure near 28N133W, supporting moderate to fresh NE winds from 10N to 15N. Seas are to 8 ft within these winds. Elsewhere under the influence of the ridge gentle to moderate winds prevail with seas of 4 to 7 ft based on altimeter data. For the forecast, Pilar will move to 10.6N 112.0W Sun morning, 11.1N 113.8W Sun afternoon, 11.8N 115.2W Mon morning, 12.7N 116.3W Mon afternoon, weaken to a remnant low near 13.6N 117.5W Tue morning, and 14.6N 118.7W Tue afternoon. Pilar will dissipate Wed afternoon. Otherwise, a cold front will move across the NW corner of the forecast area on Sun, reach from 30N130W to 25N140W by Mon morning, and begin to weaken as it approaches Baja California Norte on Tue morning. A new swell event will follow the front building seas to 8 to 11 ft on Mon. As the front moves SE a large area of 8 to 9 ft seas will dominate most of the waters N of 20N W of 115W by Wed morning. $$ GR