000 AXPZ20 KNHC 200359 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Aug 20 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 0000 UTC surface analysis and satellite imagery through 0355 UTC. ...SPECIAL FEATURES... Hurricane Hilary is centered near 25.3N 114.6W at 20/0300 UTC, moving north-northwest at 16 kt. Estimated minimum central pressure is 968 mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt. Scattered moderate to strong convection is occurring north of 23N and east of 119W. Seas in excess of 12 ft extend to 270 nm in the NE quadrant and to 390 nm in the SE quadrant and to 330 nm in the SW quadrant and to 270 nm in the NW quadrant of the center, including within the southern Gulf of California. Continued weakening is expected, but Hilary is likely to still be a hurricane when it approaches the west coast of the Baja California Peninsula later tonight. Hilary is expected to weaken to a tropical storm before it reaches southern California. Preparations for flooding impacts associated with Hilary should be completed as soon as possible, as heavy rainfall will begin well in advance of the center. In the Southwestern United States, the potentially historic amount of rainfall is expected to cause flash, urban, and arroyo flooding including landslides, mudslides, and debris flows. Dangerous to locally catastrophic flooding impacts are expected early Sunday through early Monday. Large swells generated by Hilary will affect portions of the Baja California Peninsula and southern California over the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. 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 Hilary NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A small segment of an Atlantic tropical wave is along 83W, extending south from the coast of Panama to 06N. Scattered moderate to isolated strong convection is noted from 02N to 12N and between east of 90W. A tropical wave is along 101W, north of 03N moving and moving westward at 10-15 kt. Scattered moderate to isolated strong convection is present from 05N to 11N and between 90W and 103W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N85W to 09N105W and from 11N121W to 08N140W. Scattered moderate to isolated strong convection is observed from 12N to 18N and from 109W and 117W and also from 06N to 10N and from 125W and 131W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on Hurricane Hilary. Outside of Hurricane Hilary, satellite imagery show a few showers and isolated thunderstorms over the Mexican offshore waters that originated over Mexico and Central America, mainly confined to within 120 nm of the coast. Moderate to fresh winds are noted off southern Mexico and the Gulf of Tehuantepec with seas of 4-7 ft. For the forecast, winds and seas will gradually diminish over Mexican offshore waters Sun through early Mon in the wake of Hilary. Fresh to strong gap winds will pulse across the Gulf of Tehuantepec through mid week, mainly at night. Looking ahead, another area of low pressure has a low chance of development off southern Mexico through the middle of the week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh easterly winds are pulsing across the Papagayo region, allowing seas to build to 6 ft. Gentle to moderate winds are occurring elsewhere, with mainly 3-5 ft seas in S-SW swell. For the forecast, moderate to fresh E winds will pulse at night across the Gulf of Papagayo region through Tue. Light to gentle breezes and slight to moderate seas will persist elsewhere through tomorrow. SW-W monsoonal winds will increase S of 09N beginning tonight between Colombia and waters north of the Galapagos, then increase offshore of Costa Rica and western Panama Mon and Tue, then diminish late Wed and Thu as the monsoon trough lifts northward. ...REMAINDER OF THE AREA... Moderate to locally strong SW winds north of 08N and between 106W and 126W is associated with the southerly flow towards Hurricane Hilary. Seas in these waters are 8-10 ft. Elsewhere in the basin, a weak pressure pattern prevail, sustaining moderate or weaker winds and moderate seas. For the forecast, SW winds will start to increase south of the monsoon trough and east of 110W later today and continue through midweek with building seas. $$ DELGADO