258 AXPZ20 KNHC 121557 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Sep 12 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 broad area of low pressure offshore of southern Mexico is producing a large area of disorganized showers and thunderstorms. Further development of this system is possible during the next couple of days as long as it remains over water, and a tropical depression could form tomorrow or early Monday while the system moves northwestward toward the southern and southwestern coasts of Mexico. Further development is not expected by midweek due to interaction with land. Regardless of development, this system will likely produce heavy rains across portions of southern Mexico during the next couple of 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... The axis of a tropical wave is near 84W north of 02N, moving west at 10-15 kt. Scattered moderate to isolated strong convection is noted from 08N to 12N between 86W and 89W. The axis of a tropical wave is near 98W, moving west at 10 kt. Scattered moderate to isolated strong convection is noted from 10N to 16N between 92W and 101W. Low pressure 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... The monsoon trough extends from 11N86W to 1008 mb low pressure near 14.5N97W to 08N125W to 10N140W. Aside from convection noted in the tropical waves section above, scattered moderate convection is noted north of 06N and east of 80W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on the developing area of low pressure with the potential for developing into a tropical cyclone. A couple of recent altimeter satellite passes confirmed large seas reaching from 8 to 12 ft starting to enter the offshore waters of southern Mexico. This is in the same area where a 1008 mb low pressure area is analyzed off Puerto Angel, moving west along the coast of western Oaxaca. Farther north, the remnant low of Olaf is centered about 180 nm west-southwest of Cabo San Lazaro in Baja California Sur. Winds and seas have diminished near this low, although surrounding SW swell is maintaining seas to 7 ft off Baja California Sur. For the forecast, strong winds and rough seas will accompany the low pressure off Puerto Angel as it continues to move westward along the coast of western Oaxaca this afternoon and tonight before going inland over eastern Guerrero through Monday. There is a small window for further development, but regardless of development, the SW swell will continue to cause rough seas off southern Mexico and the potential for hazardous surf along the coast through the early part of the week. Heavy rainfall is also likely over inland areas. Farther north, seas will build to 8 or 9 ft off Baja California through the early part of the week and a mix of NW and S swell. 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