000 AXPZ20 KNHC 110240 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0240 UTC. ...SPECIAL FEATURES... Recently downgraded Tropical Depression Olaf is centered near 24.7N 113.3W at 11/0300 UTC moving W at 5 kt. Estimated minimum central pressure is 1003 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Max seas are peaking near 12 ft. There is no significant convection near the center of Olaf. Olaf will continue to weaken to a remnant low Sat morning. Seas will continue to subside, and will fall below 12 ft overnight. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP5.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP5.shtml for more details. A tropical wave is moving across the eastern Pacific with axis near 92W. A broad area of low pressure is expected to form along this wave to the south of the southern coast of Mexico during the next day or so. Thereafter, environmental conditions could support some development of this system, and a tropical depression could form late this weekend or early next week while it moves generally northwestward 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... The axis of a tropical wave is near 92W north of 05N, moving west at 10 to 15 kt. Scattered moderate convection is evident from 07N to 15N between 87W and 95W. This tropical wave will be monitored over the next several days for the potential for tropical cyclogenesis. The axis of a tropical wave is near 104W/105W north of 05N to 16N, moving westward at 10 to 15 kt. Scattered moderate isolated strong convection is noted from 07N to 15N between 100W and 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N86W to 13N91W to 10N120W to 09N130W. Aside from the convection mentioned in the Tropical Wave section, scattered moderate to isolated strong convection is noted from 03N to 10N between 80W and 87W, and from 07N to 15N between 95W and 100W. Scattered moderate convection is from 04N to 07N between 127W and 132W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on Tropical Depression Olaf, and a tropical wave with potential for spawning a tropical cyclone. Fresh N gap wind will pulse across the Gulf of Tehuantepec currently, in response to a tightening pressure gradient ahead of an approaching tropical wave. Long- period SW swell is also starting to impact 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. Farther north, Tropical Storm Olaf has weakened to a Tropical Depression this evening. Winds and seas will continue to decrease overnight. Moderate SE winds and slight seas are noted across the Gulf of California. Outside of the immediate area of Olaf, gentle to moderate NW winds persist off Baja California, with moderate seas. For the forecast, a broad area of low pressure is expected to form along tropical wave off southern Mexico during the next day or two, and there is a medium chance this low could develop further into a tropical depression late this weekend or early next week while it moves west- northwestward or northwestward near the southern and southwestern coasts of Mexico. Regardless of development, seas will build off southern Mexico Sat into Tue due to southwest swell. 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 8 ft range off Guatemala and El Salvador in SW swell. The monsoon trough extends from central Panama to the Pacific coast of northwest Costa Rica and Nicaragua. Convergent SW flow into the monsoon trough is supporting areas of showers and thunderstorms along these coastal areas, to include in the Gulf of Panama. Clusters of showers and thunderstorms are active off the Azuero Peninsula of Panama as well. Farther south, gentle 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 110W. 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. $$ AL