####018007714#### WTUS86 KSGX 182048 HLSSGX CAZ043-048-050-055>058-060>062-065-552-554-190500- Hurricane Hilary Local Statement Intermediate Advisory Number 9A National Weather Service San Diego CA EP092023 148 PM PDT Fri Aug 18 2023 This product covers EXTREME SOUTHWESTERN CALIFORNIA Hilary to produce rare and dangerous flash flooding and tropical storm-force winds. NEW INFORMATION --------------- * CHANGES TO WATCHES AND WARNINGS: - None * CURRENT WATCHES AND WARNINGS: - A Tropical Storm Watch is in effect for Apple and Lucerne Valleys, Coachella Valley, Orange County Coastal Areas, Orange County Inland Areas, Riverside County Mountains, San Bernardino County Mountains, San Bernardino and Riverside County Valleys-The Inland Empire, San Diego County Coastal Areas, San Diego County Deserts, San Diego County Mountains, San Diego County Valleys, San Gorgonio Pass Near Banning, and Santa Ana Mountains and Foothills * STORM INFORMATION: - About 1110 miles south-southeast of San Mateo Point CA or about 1040 miles south-southeast of Mouth of Tijuana River CA - 18.2N 111.8W - Storm Intensity 145 mph - Movement Northwest or 315 degrees at 10 mph SITUATION OVERVIEW ------------------ Hurricane Hilary will weaken to a tropical storm as it approaches Southern California this weekend. Flash flooding will be possible across the whole region, with rare and dangerous flooding possible across the mountains and deserts. Strong, tropical-storm force winds will be possible Sunday into Monday. POTENTIAL IMPACTS ----------------- * FLOODING RAIN: Prepare for life-threatening rainfall flooding having possible devastating impacts across Southern California. Potential impacts include: - Extreme rainfall flooding may prompt numerous evacuations and rescues. - Rivers and tributaries may overwhelmingly overflow their banks in many places with deep moving water. Small streams, creeks, canals, and ditches may become raging rivers. In mountain areas, deadly runoff may rage down valleys while increasing susceptibility to rockslides and mudslides. Flood control systems and barriers may become stressed. - Flood waters can enter numerous structures within multiple communities, some structures becoming uninhabitable or washed away. Numerous places where flood waters may cover escape routes. Streets and parking lots become rivers of raging water with underpasses submerged. Driving conditions become very dangerous. Numerous road and bridge closures with some weakened or washed out. Prepare for life-threatening rainfall flooding having possible extensive impacts across Southern California. * WIND: Prepare for dangerous wind having possible significant impacts across Southern California. Potential impacts in this area include: - Some damage to roofing and siding materials, along with damage to porches, awnings, carports, and sheds. A few buildings experiencing window, door, and garage door failures. Mobile homes damaged, especially if unanchored. Unsecured lightweight objects become dangerous projectiles. - Several large trees snapped or uprooted, but with greater numbers in places where trees are shallow rooted. Several fences and roadway signs blown over. - Some roads impassable from large debris, and more within urban or heavily wooded places. Hazardous driving conditions on bridges and other elevated roadways. - Scattered power and communications outages, but more prevalent in areas with above ground lines. Also, prepare for hazardous wind having possible limited impacts across Southern California. * TORNADOES: Prepare for a tornado event having possible limited impacts across EXTREME SOUTHWESTERN CALIFORNIA. Potential impacts include: - The occurrence of isolated tornadoes can hinder the execution of emergency plans during tropical events. - A few places may experience tornado damage, along with power and communications disruptions. - Locations could realize roofs peeled off buildings, chimneys toppled, mobile homes pushed off foundations or overturned, large tree tops and branches snapped off, shallow-rooted trees knocked over, moving vehicles blown off roads, and boats pulled from moorings. * SURGE: Little to no impacts are anticipated at this time across EXTREME SOUTHWESTERN CALIFORNIA. PRECAUTIONARY/PREPAREDNESS ACTIONS ---------------------------------- * EVACUATIONS: Listen to local official for recommended preparedness actions, including possible evacuation. If ordered to evacuate, do so immediately. * OTHER PREPAREDNESS INFORMATION: Now is the time to check your emergency plan and emergency supplies kit and take necessary actions to protect your family and secure your home or business. When making safety and preparedness decisions, do not focus on the exact forecast track since hazards such as flooding rain, damaging wind gusts, storm surge, and tornadoes extend well away from the center of the storm. If in a place that is vulnerable to high wind, such as near large trees, a manufactured home, upper floors of a high-rise building, or on a boat, plan to move to safe shelter. If you live in a place particularly vulnerable to flooding, such as near the ocean or a large inland lake, in a low-lying or poor drainage area, in a valley, or near an already swollen river, plan to move to safe shelter on higher ground. Always heed the advice of local officials and comply with orders that are issued. Do not needlessly jeopardize your life or the lives of others. When securing your property, outside preparations should be concluded as soon as possible before conditions deteriorate. The onset of strong gusty winds or flooding can cause certain preparedness activities to become unsafe. Be sure to let friends and family members know of your intentions for weathering the storm and your whereabouts. Have someone located away from the threatened area serve as your point of contact. Share vital contact information with others. Keep cell phones handy and charged. Check on those who may not be fully aware of the situation or who are unable to make personal preparations. If you are a visitor, know the name of the county in which you are located and where it is relative to current watches and warnings. If staying at a hotel, ask the management staff about their onsite disaster plan. Listen for evacuation orders, especially pertaining to area visitors. Closely monitor weather.gov, NOAA Weather Radio and local news outlets for official storm information. Listen for possible changes to the forecast. There is a threat from tornadoes with this storm. Have multiple ways to receive Tornado Warnings. Be ready to shelter quickly. * ADDITIONAL SOURCES OF INFORMATION: - For information on appropriate preparations see ready.gov - For information on creating an emergency plan see getagameplan.org - For additional disaster preparedness information see redcross.org NEXT UPDATE ----------- The next local statement will be issued by the National Weather Service in San Diego CA around , or sooner if conditions warrant. $$ EA