000 AXPZ20 KNHC 160926 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Aug 16 2023 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 0900 UTC. ...SPECIAL FEATURES... Hurricane Fernanda is centered near 17.3N 124.1W at 16/0300 UTC, moving west at 12 kt. Estimated minimum central pressure is 975 mb. Maximum sustained wind speed is 80 kt with gusts to 105 kt. Numerous moderate to isolated strong convection is noted within 90 nm SW and 60 nm NE semicircles of center. Peak seas are near 30 ft with the 12 ft seas extending within 90 nm of center, except 120 nm NE quadrant. Seas will continue to stay above 20 ft through tonight into Thu, with seas subsiding by the end of the week as the system approaches 140W. Fernanda is barely holding on to hurricane strength. Rapid weakening is forecast to continue, and Fernanda is likely to become a tropical storm today, and a post-tropical low on Thursday. On the forecast track, a general westward motion is expected to continue for the next few days. 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 Fernanda NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gale Warning (EP90): Showers and thunderstorms are continuing to show signs of organization in association with a broad area of low pressure located a few hundred miles south of Acapulco, Mexico. Clusters of moderate to strong convection are noted from from 10N to 15N between 99W and 105W. Altimeter data provided observations of seas in the 12 to 15 ft range within about 180 nm NE quadrant of the low center. Environmental conditions appear conducive for continued development, and a tropical depression or tropical storm is anticipated to form within the next day or so. The system is expected to move west- northwestward to northwestward, roughly parallel to the coast of southwestern Mexico and the Baja California peninsula during the next several days. Additional information on this system, including gale warnings, can be found in High Seas Forecasts issued by the National Weather Service. This system has a high chance of tropical cyclone formation within 48 hours. A notable increase in winds and seas is forecast by the computer models in association with this developing system. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and refer to the latest NHC Tropical Weather Outlook at wwww.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 101W from 05N northward to the coast of Mexico, west of Acapulco, Mexico, moving W at 5 to 10 kt. A low pressure of 1002 mb is along the wave axis near 11.7N100.8W. Clusters of moderate to strong convection are noted from from 10N to 15N between 99W and 105W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 09N84W to 1002 mb low pressure located near 11.7N100.8W to 12N110W. The ITCZ axis stretches from 08N130W to beyond 08N140W. Aside from the convection associated with the low pressure/tropical wave mentioned above, scattered moderate to isolated strong convection is noted from 03N to 07N between 78W and 83W, and from 08N to 13N between 95W and 99W. Scattered moderate convection is observed from 09N to 12N between 114W and 124W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section on the Gale Warning in the Mexico offshores due to EP90. Outside of EP90, a surface ridge dominates the offshore forecast waters of Baja California. This is causing moderate to locally fresh NW to N winds off Baja California Norte with gentle to locally moderate winds elsewhere in the Baja California offshore waters. Seas are 4 to 6 ft. In the Gulf of California, light to gentle variable winds are noted with seas of 1 to 2 ft, except seas of 3 to 4 ft near the entrance to the Gulf. Higher winds are noted near the Sonora/Sinaloa border due to the presence of convective activity. Light to gentle winds are elsewhere off the southern Mexico offshore waters with 4-6 ft seas in SW swell. For the forecast, moderate to fresh NW winds are expected offshore the coast of Baja California from Punta Eugenia to Cabo San Lazaro mainly at night through the next few days. Please see the Special Features section for more information on EP90. Looking ahead, an area of low pressure could form south of the Gulf of Tehuantepec over the weekend. Some gradual development of this system is possible thereafter while it moves generally west-northwestward. This system has a low chance of tropical cyclone development over the next 48 hours, and 7 days. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong winds are seen in the Papagayo region, and downwind to near 88W. Recent scatterometer data indicate moderate to fresh N winds across the Gulf of Panama to about 08N. Similar wind speeds are also noted near the Colombia/Ecuador border. Light to gentle winds are elsewhere across the Central America and South American offshore waters. Seas are generally 4 to 6 ft due to long-period SW swell, except 1 to 3 ft in the Gulf of Panama, and 3 to 4 ft just offshore Colombia. For the forecast, fresh to locally strong winds are expected in the Papagayo region trough Thu night. The broad area of low pressure near southern Mexico will continue to move westward and away from the Guatemala and El Salvador offshore waters tonight into Wed. Winds will increase to moderate between Ecuador and the the Galapagos Islands waters by Wed night and will persist the rest of the week. Expect moderate seas within S to SW swell in this area. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on Hurricane Fernanda. A ridge dominates roughly the waters N of 20N and W of 115W. The pressure gradient between the ridge and tropical cyclone Fernanda supports an area of moderate to fresh winds mainly from 16N to 22N between 118W and 134W based on satellite derived wind data. Light to gentle winds are noted elsewhere under the influence of the ridge. Seas range 4-6 ft in this area within NW swell. For the forecast, based on latest NHC forecast advisory, Fernanda will weaken to a tropical storm near 17.2N 127.5W this afternoon, move to 17.1N 130.2W Thu morning, become post-tropical and move to 17.2N 132.9W Thu afternoon, weaken to a remnant low near 17.3N 135.7W Fri morning, 17.5N 138.7W Fri afternoon, and will be W of area near 17.7N 141.6W Sat morning. Fernanda will change little in intensity as it moves to near 17.7N 147.6W early Sun. $$ GR