061 AXPZ20 KNHC 161622 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Newly upgraded Tropical Storm Hilary is centered near 12.4N 102.6W at 16/1500 UTC, moving west-northwest at 12 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous strong convection covers a widespread area in the Mexico offshore waters and the high seas from 08N to 18N between 99W and 108W. Peak seas are currently around 17 ft with the 12 ft seas extending within 240 nm in the NE quadrant, 210 nm in the SE quadrant, 180 nm NW quadrant and 90 nm in the SW quadrant. Hilary will continue moving in a west- northwest motion with a gradual turn to the northwest in a day or so. Steady to rapid strengthening is forecast for the next few days. Hilary is expected to become a hurricane on Thursday. Large swells generated by Hilary will affect portions of the coast of southwestern Mexico and the Baja California peninsula over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. Seas are expected to become high or very high by Thu and phenomenal by Fri. 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. Newly downgraded Tropical Storm Fernanda is centered near 17.1N 126.8W at 16/1500 UTC, moving west at 13 kt. Estimated minimum central pressure is 994 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Some showers are around the system but no significant convection is noted at this time. Seas are around 25 ft with the 12 ft seas extending 120 nm in the NE quadrant and 90 nm in the NW quadrant and southern semicircle. Fernanda will continue moving west over the next few days. Continued rapid weakening is forecast during the next 48 hours, and Fernanda is likely to become a post-tropical remnant low within a couple of 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. ...TROPICAL WAVES... A tropical wave is along 88W from 10N northward to the coast of El Salvador, moving W at 5 to 10 kt. Isolated showers and thunderstorms are noted within 50 nm of the axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 07N81W to 12101W to 13N120W. The ITCZ extends from 07N133W to beyond 08N140W. Scattered moderate to isolated strong convection is noted from 01N to 08N between 79W and 90W. Scattered moderate convection is noted from 06N to 14N between 109W and 129W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features for information on Tropical Storm Hilary. Outside of TS Hilary, 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 light to gentle winds elsewhere in the Baja California offshore waters. Seas are 4 to 6 ft in mixed swell. 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. Light to gentle winds are elsewhere off the southern Mexico offshore waters with 4-6 ft seas in mostly SW swell. For the forecast, Tropical Storm Hilary will move to 13.1N 104.3W this evening, strengthen to a hurricane near 14.1N 106.5W Thu morning, 15.4N 108.7W Thu evening, 16.7N 110.7W Fri morning, 18.5N 112.3W Fri evening, and 20.4N 113.6W Sat morning. Hilary will change little in intensity as it moves to near 25.7N 114.8W by early Sun. Moderate to fresh NW winds are expected offshore the coast of Baja California from Punta Eugenia to Cabo San Lazaro mainly at night through Thu night. 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 89W. 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 5 ft just offshore Colombia. For the forecast, fresh to locally strong winds are expected in the Papagayo region trough Sat night. 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 Tropical Storm 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 winds mainly from 11N to 23N between 131W and 140W based on satellite derived wind data. Light to gentle winds are noted elsewhere under the influence of the ridge, N of 25N and W of 120W. Gentle to locally moderate S to SW winds are noted S of the ITCZ/monsoon trough. Seas range 4-6 ft across the forecast waters within NW swell. For the forecast, based on latest NHC forecast advisory, Fernanda will move to 16.9N 128.9W this evening, weaken to a tropical depression near 16.9N 131.6W Thu morning, become a remnant low and move to 16.9N 134.2W Thu evening, 17.0N 136.9W Fri morning, 17.0N 139.6W Fri evening, and 17.0N 142.4W Sat morning. Fernanda will dissipate early Sun. $$ AReinhart