000 AXPZ20 KNHC 171557 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Sep 17 2022 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 1500 UTC. ...SPECIAL FEATURES... The center of Lester is very near the coast of Mexico. Risk of flash flooding and mudslides will persist today across portions of the southwestern Mexico. Tropical Storm Lester is centered near 16.0N 99.0W at 17/1500 UTC moving NW at 9 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Scattered moderate to isolated strong convection is noted from 14N to 16N between 95W and 102W. A cluster of moderate to isolated strong convection is ahead of Lester over Zihuatanejo and regional waters from 16.5N-18N between 101-102W. The tropical storm is forecast to continue moving toward the coast during the next few hours and should move inland over southwestern Mexico today. Rapid weakening leading to dissipation is expected once the center of Lester reaches the coast of Mexico. Lester is forecast to produce rainfall total of 8 to 12 inches with maximum totals of 16 inches along the coasts of Guerrero and Michoacan. Tropical storm conditions are expected along portions of the coast within the tropical storm warning area and are possible within the tropical storm watch area during the next few hours. Swells generated by Lester are affecting portions of the coast of southern and southwestern Mexico, and this will continue into the weekend. 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 T.D. Thirteen-E NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Southwest of Southwestern Mexico: A low pressure system located near 15.5N106.5W continues to produce shower and thunderstorm activity a few hundred miles southwest of Manzanillo, Mexico. This disturbance continues to show signs of organization, and a tropical depression will likely form later today or tonight. The low is forecast to meander off the southwestern coast of Mexico this weekend, and then turn north- northwestward early next week. For more information on this system, including gale warnings, please see High Seas Forecasts issued by the National Weather Service. Numerous moderate to scattered strong convection is seen within 210 nm W semicircle of low center. An area of minimal gale force winds is noted within 60 nm SE semicircle of the low center. A broad area of fresh to strong SW-W winds remains S of the low, covering the waters from 09N to 15N between 102W and 114W. Seas of 8-15 ft in long period S to SW swell are occurring across this area. A gale warning has been issued for this area. The latest Tropical Weather Outlook gives this system a high chance of tropical cyclone formation within the next 48 hours. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details on both areas. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N84W to 14N95W, then resumes from near 14N112W to 12N122W to 11N140W. Aside from the convection associated with Lester and the low pressure located a few hundred miles southwest of Manzanillo, Mexico, scattered moderate convection can be found N of 04N and E of 80W, including the Gulf of Panama, from 08N to 11N between 84W and 91W, and from 10N to 13N W of 136W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to the Special Features section for details on T.S. Lester and a low pressure area located a few hundred miles southwest of Manzanillo, Mexico. A ridge dominates the offshore of Baja California producing moderate to locally fresh NW to N winds N of Cabo San Lazaro, and gentle to moderate NW winds between Cabo San Lazaro and Los Cabos. Seas are generally in the 6-7 ft range except to 8 ft offshore of Baja Norte. Light to gentle winds and seas of 1-3 ft prevail in the Gulf of California. Marine conditions S of Cabo Corrientes are dominated by long period SW swell and swell being generate by the above mentioned low pressure area with a high chance of tropical cyclone formation. For the forecast, Lester will move inland and weaken to a tropical depression near 17.3N 99.9W this evening, and dissipate Sun morning. A ridge will remain in place across the offshore waters of Baja California through the weekend and maintain moderate to fresh winds. Gentle to occasionally moderate mainly southerly winds and 1-3 ft seas are expected in the Gulf of California. Marine conditions will begin to deteriorate between Los Cabos and Cabo Corrientes on Sat night, as the low pressure currently located a few hundred miles southwest of Manzanillo, Mexico moves northward spreading gale conditions and high seas across the area. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh W-SW winds prevail south of the monsoon trough, while light and variable winds are north of the trough from the Gulf of Papagayo region to Guatemala coastal waters. Seas are 6-8 ft in SW swell across the offshore waters, with the exception of 8-9 ft well offshore of Guatemala. A moist and unstable environment interacting with the monsoon trough persists across the area, mainly N of 05N, resulting in active showers and thunderstorms. For the forecast, mainly gentle to moderate winds will persist across the offshore forecast waters, with seas of 6-9 ft in SW swell through Sun. An area of low pressure could form S of Central America early next week. Environmental conditions are forecast to be conducive for some gradual development while the system moves west- northwestward near or offshore the coast of southern Mexico through mid-week. A very moist and unstable atmospheric environment will help maintain active weather across most of the offshore waters over the next few days. REMAINDER OF THE AREA... Refer to the Special Features section for details on T.S. Lester and a low pressure area located a few hundred miles southwest of Manzanillo, Mexico. High pressure dominates the waters north of the monsoon trough and west of about 118W, centered on a 1034 mb high near 45N155W. The pressure gradient between this system and a 1011 mb low pressure located near 11N139W supports an area of fresh to locally strong NE winds from 11N to 13N W of 136W. Seas are 7-8 ft within these winds. Gentle to moderate winds prevail elsewhere north of the monsoon trough. Moderate to locally fresh southerly winds are south of the monsoon trough along with 5-8 ft seas, outside of T.S. Lester and a low pressure area located a few hundred miles southwest of Manzanillo, Mexico. A broad area of fresh to strong SW-W winds prevail S of these tropical systems to 08N. Cross equatorial SW swell continues to move into the region and is maintaining seas of 6-8 ft to the south of the monsoon trough and west of the Galapagos Islands. For the forecast, high pressure will continue to dominate the northern forecast waters. A weak cold front is forecast to enter the discussion area on Sun, extending roughly from 30N125W to 27N135W to 28N140W by Sun night. Seas of 8-10 ft in northerly swell will follow the front reaching the waters N of 27N and W of 126W by Mon morning. An area of fresh to locally strong NE winds with seas to 8 ft will move westward in tandem with the low pressure located near 11N139W. Additional pulses of cross- equatorial SW swell will continue to propagate across the forecast waters east of 130W. $$ GR