SPECIAL Currently in Los Angeles — August 19, 2023: Hilary arrives
Plus, flash flooding in the deserts is expected to be catastrophic.
The weather, currently.
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Hilary arrives on Saturday
Friday was the calm before the storm. I took a day trip to Temecula where it was still sunny and a balmy 97. But I did start to see some upper level clouds in the south.
On Saturday, the storm will begin.
Things will rapidly deteriorate as the center of Hilary arrives as a tropical storm on Saturday evening in San Diego County. Up in LA, there is a threat for tropical storm force winds and substantial rainfall —smack dab in the middle of our dry season.
Hilary is the first fully tropical cyclone to make landfall in Southern California in the past 80 years. Hilary’s main risk will be flooding, and will act to pull unimaginable amounts of water northward from the record-warm tropical Pacific. By one measure Hilary’s moisture transport will be 400% more than normal, and will rival some of the strongest atmospheric rivers ever measured for any month. A large swath of southern California will receive a year’s worth of rain this weekend. Parts of the Imperial Valley and Death Valley will receive 2-3x their annual rainfall.
Tropical Storm warnings are now in effect as far north as Ventura County.
Here’s the latest from the National Weather Service, which is now saying “Dangerous to locally catastrophic flooding will be likely”:
Heavy rainfall in association with Hilary is expected to impact the Southwestern United States through early next week, peaking on Sunday and Monday. Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada. Dangerous to locally catastrophic flooding will be likely.
That’s putting it mildly. Hurricane Hilary will be a transformative event for the deserts of southern California and southern Nevada.
Places likely to be hit the hardest by flash flooding include (but definitely not limited to:
Imperial Valley / Coachella Valley / Palm Springs
Also if you are in San Diego, Los Angeles, Las Vegas or anywhere in red on the map below — prepare for sudden and severe street flooding. The City of Riverside has prepared a great thread of tips to get ready for the storm if you live in an urban area.
Here’s the region-wide predicted rainfall totals, from the National Weather Service:
For the Inland Empire, San Diego, and the deserts, here is what you can expect in terms of peak wind speeds:
And here is what you can expect in total rainfall. Again, if you are east of metro LA/Inland Empire/San Diego, this is going to be a year’s worth of rain or more: