000 AXPZ20 KNHC 170931 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Aug 17 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... Tropical Storm Hilary is centered near 14.6N 106.3W at 17/0900 UTC, moving west-northwest at 11 kt. Estimated minimum central pressure is 988 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Numerous moderate to strong convection is noted within 90 nm of center, except 120 nm SE quadrant. Numerous moderate to isolated strong convection is noted elsewhere from 10N to 17N between 102W and 111W. An outer band associated with the large circulation of Hilary crosses between Las Marias Islands and cabo Corriente and extends toward the Revillagigedo Islands. Peak seas are 28 ft with the 12 ft seas extending within 270 nm in the E semicircle, 120 nm in the SW quadrant, and 150 nm in the NW quadrant. Seas are expected to become high to very high during the next 24 to 36 hours, with an extensive area of seas greater than 8 ft. Rapid strengthening is forecast, and Hilary will become a hurricane very soon. It could become a major hurricane by tonight or early Friday. On the forecast track, a turn toward the northwest is expected Friday morning, followed by a turn toward the north-northwest and north on Saturday. The center of Hilary will approach the Baja California peninsula over the weekend. 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. Interests elsewhere on the Baja California peninsula and along the coast of northwestern mainland Mexico should closely monitor the progress of Hilary. 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 Storm Fernanda is centered near 16.6N 130.8W at 17/0900 UTC, moving west at 13 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Scattered moderate convection is noted W of center from 15N to 17N between 130W and 132W. Peak seas are around 14 ft with the 12 ft seas extending within 90 nm of center, expect 60 nm SW quadrant. Fernanda is barely a tropical cyclone. Continued weakening is forecast during the next couple of days, and Fernanda is likely to become a post-tropical cyclone today and dissipate by the weekend. Seas will drop below 12 ft tonight into Fri as Fernanda approaches 140W. 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 91W from 04N northward to across western Guatemala, moving W at about 10 kt. Scattered moderate to isolated strong convection is noted near the southern end of the wave axis from 04N to 09N between 90W and 92W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N84W to 08N88W to 11N97W then resumes W of T.S. Hilary from 14N112W to 12N125W to 08N135W. The ITCZ stretches from 08N135W to beyond 07N140W. Scattered moderate to isolated strong convection is seen from 09N to 12N between 117W and 126W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on Tropical Storm Hilary. Outside of T.S. Hilary, a surface ridge dominates the offshore forecast waters of Baja California. This is causing moderate to locally fresh NW to N of Cabo San Lazaro, with gentle to moderate winds elsewhere in the Baja California offshore waters. Seas are 4 to 6 ft. In the Gulf of California, light to gentle winds are noted with seas of 1 to 2 ft, except seas of 3 to 4 ft near the entrance to the Gulf. Fresh N winds and seas to 8 ft prevail in the Tehuantepec region. For the forecast, Tropical Storm Hilary will strengthen to a hurricane near 15.5N 108.0W this afternoon, move to 16.7N 110.1W Fri morning, 18.1N 111.7W Fri afternoon, 19.9N 113.0W Sat morning, 22.0N 113.8W Sat afternoon, and 24.6N 114.3W Sun morning. Hilary will weaken to a tropical storm while moving inland near 31.6N 116.0W early Mon. Looking ahead, a broad area of low pressure could form offshore of the coast of southern Mexico during the early or middle part of next week. Some gradual development of this system is possible thereafter while it moves slowly west-northwestward or 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... Recent scatterometer pass indicates moderate to fresh winds across the Papagayo region and downwind to about 89W. Seas are 6 to 8 ft within these winds. Gentle to moderate winds and seas in the 4 to 6 ft range prevail elsewhere across the Central and South America forecast waters, with the exception of 1 to 3 ft seas 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 mainly at night trough Sun night. Elsewhere gentle to moderate winds and moderate seas are expected through the upcoming weekend. ...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 to fresh winds from 20N to 23N between 125W and 133W. Light to gentle winds are noted elsewhere under the influence of the ridge. Moderate to fresh winds are noted S of monsoon trough roughly between 100W and 130W. Outside of the tropical cyclones, seas range 4 to 7 ft across the forecast waters, primarily in NW swell N of 20N W of 120W, and SW swell elsewhere. For the forecast, based on latest NHC forecast advisory, Fernanda will weaken to a remnant low near 16.5N 132.7W this afternoon, move to 16.4N 135.3W Fri morning, 16.4N 137.8W Fri afternoon, and will be just W of the forecast region near 16.4N 140.5W Sat morning, 16.4N 143.0W Sat afternoon, and dissipate Sun morning. $$ GR