000 AXPZ20 KNHC 200945 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0955 UTC. ...SPECIAL FEATURES... Hurricane Hilary is centered near 27.4N 115.0W at 20/0900 UTC, moving north-northwest at 18 kt. Estimated minimum central pressure is 974 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Scattered moderate to strong convection is occurring north of 26N and east of 117W. Seas in excess of 12 ft extend to 210 nm in the NE quadrant and to 420 nm in the SE quadrant and to 390 nm in the SW quadrant and to 240 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 while it passes near the west coast of the central Baja California Peninsula this morning. 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 is about to begin. 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 through Monday morning. 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 84W, extending south from the coast of Costa Rica to 05N. Scattered moderate to isolated strong convection is observed from 00N to 10N and east of 92W. A tropical wave is along 103W, north of 03N and moving westward at 10-15 kt. Scattered moderate to isolated strong convection is seen from 04N to 13N and between 92W and 105W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to 10N101W and from 16N115W to 09N140W. Scattered moderate to isolated strong convection is noted from 11N to 19N and between 110W and 118W. Similar convection present from 06N to 10N and west of 125W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on Hurricane Hilary. Outside of the influence of Hurricane Hilary, only isolated showers are noted in the Mexican offshore waters. A recent scatterometer satellite pass captured fresh northerly winds in the Gulf of Tehuantepec, while moderate or weaker winds prevail elsewhere. Seas in the waters described are 4-7 ft. For the forecast, winds and seas associated with Hilary will diminish over Mexican offshore waters today through early Mon as the hurricane quickly moves north of the area. Strong to near gale force gap winds will pulse across the Gulf of Tehuantepec through Thursday, 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... Latest satellite-derived wind data depict fresh NE-E winds in the Papagayo region. Seas in these waters are 5-6 ft. Moderate or weaker winds and seas of 3-5 ft are prevalent in the rest of the area. For the forecast, moderate to fresh E winds will pulse at night across the Gulf of Papagayo region through Tue. SW monsoonal winds will increase S of 09N beginning today between Colombia and waters north of the Galapagos, then increase offshore of Costa Rica and western Panama Mon and Tue. Winds will then diminish late in the week as the monsoon trough lifts northward. Seas will build to 10 ft in the area described. ...REMAINDER OF THE AREA... A recent scatterometer satellite pass show fresh to strong southerly winds from 11N to 18N and between 109W and 120W. These winds are associated with strong convection in the area due to low-level convergence in 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 today and continue through midweek with building seas. $$ DELGADO