000 AXPZ20 KNHC 160948 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Sep 16 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 0600 UTC surface analysis and satellite imagery through 0840 UTC. ...SPECIAL FEATURES... Newly upgraded Tropical Storm Lester is located near 13.2N 95.9W at 0900 UTC moving N-NW at 4 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 40 kt. Scattered to numerous moderate to strong convection is noted within 270 nm W SEMICIRCLE. Scattered moderate isolated strong convection is elsewhere from 11N TO 16N BETWEEN 92W AND 96W. Lester is expected to move NW today and then increase in forward speed as it moves near the Mexican coast tonight, reaching nea 15N98.4W tonight, and then enter the Mexican mainland west of Acapulco near 17N101W Sat evening, where it will quickly weaken. Gradual strengthening is forecast until landfall. The system is expected to produce rainfall totals of 3-6 inches with isolated maximum totals of 10 inches across coastal portions of the Mexican States of Oaxaca, Guerrero, and Michoacan through Sunday morning. These rains may produce flash and urban flooding, along with isolated mudslides in areas of higher terrain near the coast. Swells generated by the depression are expected to begin affecting portions of the coast of southern Mexico by late today and 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: An area of low pressure remains nearly stationary near 15N107W at 0600 UTC, or a few hundred miles south-southwest of Manzanillo, Mexico, and continues to produce disorganized showers and thunderstorms mainly to the west of center. Estimated central pressure is 1007 mb. Environmental conditions are forecast to become more conducive for development, and a tropical depression is likely to form within the next few days. This disturbance is forecast to meander off the southwestern coast of Mexico through Sat, and then begin to move northwestward Sun through early next week. Scattered to locally numerous moderate to strong convection is noted within 300 nm nw and 150 nm sw of center. Scattered moderate isolated strong convection is elsewhere from 10.5N TO 1N BETWEEN 102W AND 112W. A broad area of fresh to strong SW-W winds is S of the monsoon trough in the vicinity of the low center, covering the waters from 07N to 14N between 100W and 110W. Seas of 8-11 ft in long period S to SW swell are occurring across 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 11N73W to T.S. Lester near 13N96W, then resumes from near 15N103W to low pres near 15N107W to 13N119W to low pres near 12.5N134W to 08.5N138W. The ITCZ extends from 08.5N138W to beyond 08N140W. Aside for the convection associated with the tropical depression and the low pressure, scattered moderate to strong convection is noted from 06N to 13N between 80W and 91W, and from 18N to 22N within 90 nm of the coast of Mexico. Widely scattered moderate convection is noted within 60 nm of the trough between 115W and 137W. 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 south- southwest of Manzanillo, Mexico. Moderate to locally fresh NW to N winds prevail across the offshore waters of Baja California and extend southward to near 22N. Seas across this area are 5-7 ft. Light to gentle winds and seas of 1-3 ft prevail in the Gulf of California. Marine conditions S of Cabo Corrientes are related to the above mentioned low pressure area with a high chance of tropical cyclone formation. Cross equatorial S swell dominates these waters with seas of 4-6 ft. For the forecast, high pressure will persist NW of Baja during the next few days and maintain moderate to fresh winds. T.S. Lester is expected to move slowly NW today and reach near 13.8N 96.9W this afternoon, then accelerate slightly and move inland along the Mexican coast near 17N101W Sat evening, then dissipate Sun. Gentle to occasionally moderate mainly southerly winds and 1-3 ft seas are expected in the Gulf of California. 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 prevail north of the trough from the Gulf of Papagayo region to Guatemala coastal waters. Seas are 5-7 ft in SW swell across the offshore waters, with the exception of 6-8 ft between Ecuador and the Galapagos Islands, as well as offshore 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. Winds could increase to moderate to fresh between northern Costa Rica and Guatemala toward the upcoming weekend as a broad area of low pressure develops along the monsoon trough. 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 recently upgraded T.S. Lester and a low pressure area located a few hundred miles south-southwest of Manzanillo, Mexico. High pressure dominates the waters north of the monsoon trough and west of about 120W, centered on a 1023 mb high near 30N134W. The related modest pressure gradient is allowing for mostly light to gentle winds over the NW corner of the forecast area. Gentle to moderate winds prevail elsewhere north of the monsoon trough. Seas are 5-7 ft, in long period southerly swell. NE winds around 20 kt and seas 7 to 8 ft are seen within 180 nm across the N semicircle of 1012 mb low pressure near 12.5N134W. 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 south- southwest of Manzanillo, Mexico. For the forecast, high pressure will build across the northern forecast waters over the next few days, as a dry and benign cold front sinks across the NW waters. This pattern will support gentle to moderate winds and seas of 4-7 ft. Winds and seas will increase some between the ridge and a transient low pressure located along the monsoon trough between 130W and 140W. Additional pulses of cross- equatorial SW swell will continue to propagate across the forecast waters east of 130W. Weather conditions will deteriorate across the offshore waters from Oaxaca to Michoacan due to the approach of Lester. $$ Stripling