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CAZ038-087-088-346>358-362-366>383-548>550-190600-



Hurricane Hilary Local Statement Advisory Number 9

National Weather Service Los Angeles/Oxnard CA  EP092023

858 AM PDT Fri Aug 18 2023



This product covers portions of Southwest California



Hilary to produce rare and dangerous flash flooding and tropical 

storm-force winds.



NEW INFORMATION

---------------



* CHANGES TO WATCHES AND WARNINGS:

    - A Tropical Storm Watch has been issued for Catalina and Santa

      Barbara Islands, Antelope Valley Foothills, San Gabriel

      Mountains, Interstate 5 Corridor, Santa Clarita Valley, and

      Highway 14 Corridor



* CURRENT WATCHES AND WARNINGS:

    - A Tropical Storm Watch has been issued for Catalina and Santa

      Barbara Islands, Antelope Valley Foothills, San Gabriel

      Mountains, Interstate 5 Corridor, Santa Clarita Valley, and

      Highway 14 Corridor



* STORM INFORMATION:

    - About 1150 miles south-southeast of Avalon CA or about 1190 

      miles south-southeast of Los Angeles Airport CA

    - 17.9N 111.4W

    - Storm Intensity 145 mph

    - Movement Northwest or 305 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 Los Angeles and Ventura Counties, and perhaps Santa Barbara 

County. Rare and dangerous flooding possible across the mountains. 

Tropical-storm-force winds will be possible Sunday into Monday.



POTENTIAL IMPACTS

-----------------



* FLOODING RAIN:

Prepare for life-threatening rainfall flooding having possible

extensive impacts across Los Angeles and Ventura Counties, and possibly

Santa Barbara County. The most dangerous conditions are expected over 

the mountains. Potential impacts include:

    - Major rainfall flooding may prompt many evacuations and rescues.

    - Small streams, creeks, canals, arroyos, and ditches may become 

      dangerous rivers. Destructive runoff may rage down mountain 

      valleys while increasing susceptibility to rockslides, mudslides,

      and debris flows. Flood control systems and barriers may become 

      stressed.

    - Streets and parking lots become rivers of moving water with

      underpasses submerged. Driving conditions become dangerous. Many

      road and bridge closures with some weakened or washed out.



Prepare for dangerous rainfall flooding having possible limited to 

significant impacts elsewhere across the area.



* WIND:

Prepare for hazardous wind having possible limited impacts across Los

Angeles and Ventura Counties, with greatest impacts over Catalina

Island and Santa Barbara Island, as well as the mountains of Los 

Angeles County. Potential impacts in this area include:

    - Damage to porches, awnings, carports, sheds, and unanchored 

      mobile homes. Unsecured lightweight objects blown about.

    - Many large tree limbs broken off. A few trees uprooted, but with

      greater numbers in places where trees are shallow rooted. Some 

      fences and roadway signs blown over.

    - A few roads impassable from debris, particularly within urban 

      or heavily wooded places. Hazardous driving conditions on 

      bridges and other elevated roadways.

    - Scattered power and communications outages.



Elsewhere across Southwest California, little to no impact is 

anticipated.



* SURGE:

Little to no impacts are anticipated at this time across Southwest

California. However, coastal flooding will be possible especially

around Catalina Island and Long Beach.



* TORNADOES:

Little to no impacts are anticipated at this time across Southwest 

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.



* 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 Los Angeles/Oxnard CA around 3PM PDT, or sooner if 

conditions warrant.



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Cohen/Kittell/Gomberg/Schoenfeld/Sweet