000 AXPZ20 KNHC 111559 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Sep 11 2021 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... A tropical wave is moving across the eastern Pacific with axis near 93W/94W A broad area of low pressure is developing along the wave a couple of hundred miles south of the Gulf of Tehuantepec. Environmental conditions are generally conducive for some development of this system if it remains over water, and a tropical depression could form late this weekend or early next week while moving west- northwestward at 5 to 10 mph near the southern and southwestern coasts of Mexico. Regardless of development, this system will likely produce heavy rains across portions of Central America and southern Mexico during the next few days. There is a medium chance for tropical cyclogenesis within the next 48 hours. Please see the latest eastern north Pacific Tropical Weather Outlook for more information. ...TROPICAL WAVES... A tropical wave is north of 02N along 78W through eastern Panama, moving west at 10-15 kt. Scattered moderate convection is noted within 30 nm of the axis. A tropical wave is north of 05N along 93W/94W through southern Mexico, moving west at 10-15 kt. Scattered moderate to isolated strong convection is noted within 30 nm of the axis of this tropical wave. Low pressure developing along the tropical wave will be monitored for the potential for tropical cyclogenesis. Please see Special Features section above for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... Segments of the monsoon trough extends from 11N86W to 13N92W to 10N110W to 11N120W, and from 15N130W to 1012 mb low pressure near 14N135W to beyond 11N140W. Aside from the convection mentioned in the Tropical Wave section, scattered moderate to isolated strong convection is noted from 05N to 07N between 80W and 83W, from 08N to 14N between 97W and 102W. Scattered moderate convection is active from 06N to 09N between 102W and 112W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on Post-Tropical Cyclone Olaf, and a developing area of low pressure with the potential for developing into a tropical cyclone. A 1006 mb low pressure center, the remnant low of Olaf, is about 100 nm west of Cabo San Lazaro near 24.5N114W. Maximum winds are likely still reaching 25 kt within 30 nm of the center of this low, with seas to 9 ft. Farther south, fresh to strong N gap winds are pulsing across the Gulf of Tehuantepec, in response to a tightening pressure gradient with a developing area of low pressure south of the Gulf of Tehunatepec. Long- period SW swell is also impacting the waters off Chiapas and eastern Oaxaca, reaching 5 to 7 ft, along with clusters of showers and thunderstorms. SW swell is also impacting most of the remaining open waters off southern Mexico, with mostly 5 to 6 ft seas. For the forecast, winds near the remnant low of Olaf will diminish to 20 kt or less by tonight, but seas to 8 ft will persist off Baja California into early next week as different groups of NW and S swell move into the region. Farther to the southeast, a broad area of low pressure is developing a couple of hundred miles south of the Gulf of Tehuantepec. Environmental conditions are generally conducive for some development of this system if it remains over water, and a tropical depression could form late this weekend or early next week while moving west- northwestward at 5 to 10 kt off southern Mexico. Regardless of development, large southwest swell will build seas off southern Mexico through early next week. Coastal areas in southern Mexico from Chiapas to Guerrero may see hazard surf and heavy rainfall Sat through early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh SW winds prevail over the offshore waters of Guatemala and El Salvador. Seas are in the 6 to 9 ft range off Guatemala and El Salvador in SW swell. Farther south, gentle to moderate southerly winds persist off Colombia and Ecuador, with seas of 6 to 8 ft in SW swell. For the forecast, large SW swell will impact region into early next week, along with moderate winds. REMAINDER OF THE AREA... A large area of moderate to fresh S to SW winds prevail south of 10N and east of 115W. Seas to 8 ft prevail over much of the tropical waters east of 120W, partly due the local wind flow, but also due in part to a larger area of cross- equatorial SW swell. Mainly gentle to moderate winds persist west of 120W, with seas to 8 ft in southerly swell reaching as far west as 130W south of 08N and 5 to 7 ft seas elsewhere. Southwest swell will continue to propagate through the waters east of 130W through the upcoming weekend, with seas ranging between 8-11 ft through early next week. $$ Christensen