Hope you were able to get a good night's rest despite a stormy night across SoCal. 


What You Need To Know

  • More than 3,000 lightning strikes were detected across SoCal Monday

  • Summer monsoon storms generally occur from mid-June to end of Sept.
  • A cut-off low pressure system off Baja California created yesterday's unsettled weather
  • Storms moved fairly quickly so rainfall amounts were relatively light for some cities

The Southwest Monsoon, which generally occurs from mid-June to Sept. 30, was quite active this summer especially over SoCal mountains and deserts. 

But the most impressive storms west of the mountains came yesterday — in early fall.     

Courtesy: Collin Wooler of Huntington Beach

A pesky cut-off low pressure system off Baja California was in the right place at the right time. It spun up some monsoon moisture from the south and created unsettled weather over SoCal. 

Radar imagery between 9pm-10pm Monday

The National Weather Service in San Diego counted more 2,074 in-cloud and cloud-to-ground lightning strikes over San Diego, Riverside and Orange counties

The NWS in Oxnard counted more than 1,000 strikes over LA, Ventura and Santa Barbara counties.  

Courtesy: Alejandro Tamayo of Tijuana

 

Origin of storms

Storms began yesterday down in Mexico over Baja California, then pushed northward into San Diego county in the late morning and the rest of SoCal in the early afternoon and lasted on and off through midnight.   

A majority of the storms occurred over the ocean and along coastal cities. But some storms popped up over inland cities including the mountains.  

Courtesy: Christopher Nunley near LAX

Some thunderstorms created gusty winds, pea-sized and marble-sized hail and brief heavy rain — enough to cause ponding, but no major flooding. 

Both the National Weather Service in San Diego and in Oxnard didn't issue any Flash Flood Warnings at any time yesterday.   

It turns out yesterday's storms moved quickly and thunderstorm training didn't occur, meaning thunderstorms didn't move over the same area in a relatively short period of time.

Rainfall through this morning

Here's a list of rainfall amounts for some cities.  

0.47" - Fullerton

0.39" - Corona Del Mar

0.30" - Costa Mesa

0.27" - Laguna Hills

0.25" - Venice

0.20" - San Juan Capistrano

0.20" - LA City College

0.20" - Murrieta

0.18" - Port Hueneme

0.17" - Santa Monica

0.16" - Inglewood

0.16" - Temecula

0.13" - USC

0.10" - Montebello

0.09" - Corona Luiseno

0.09" - Pasadena

0.08" - Silverstrand Beach

0.05" - Oxnard

0.04" - Newhall

0.04" - Bel Air

0.03" - Van Nuys

0.03" - Long Beach

0.02" - Alhambra

0.01" - Fillmore