Thunder and lightning are pretty rare near the coast of California. However, we had a bit of it today due to the strong low-pressure system that moved through northern California today (wind gusts at 58 mph and 97 mph were reported yesterday at SFO and Angel Island respectively).

Here’s a screenshot of some of the strikes from about 11:00 am to noon as measured by W6BUL-5 located in Vacaville, CA.

For course, the National Weather Service was on it this morning. From the 5:00 am area forecast discussion…

ADDITIONAL SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY AS THE UPPER LOW CENTER MOVE ACROSS THE NORTHERN PART OF OUR CWA. THE ATMOSPHERE HAS BECOME UNSTABLE BEHIND THE FRONT THIS MORNINGS KOAK SOUNDING HAS AN LI OF -1.1 WITH 185 J/KG OF CAPE. WITH A SOUNDING FORECAST MAX T OF 60F THE CAPE INCREASES TO 637 J/KG WITH AN LI OF -3.9…PRETTY RESPECTABLE FOR OUR REGION.

CAPE is the convective available potential energy, and LI is the lifting index both of which are measures of atmospheric instability. The KOAK sounding is the data retrieved from radiosondes (an upper-air probes) attached to weather balloons released from Oakland, CA. You can find the current KOAK sounding here, and below is part of this morning’s sounding..

NOAA’s storm prediction center issued this discussion for California.

PRIMARY BROKEN BAND OF TSTMS — WHICH HAS INCLUDED A FEW SMALL SUPERCELLS — IS EVIDENT ATTM IN VIS AND REFLECTIVITY IMAGERY FROM SIERRAN FOOTHILLS ESE SAC…SWWD TO NRN FRINGES OF MRY BAY.

Doppler radar station KMUX picked up on some of the rain showers in this image from around noon today.

Notice the area of strong radar reflection located in the Santa Cruz Mountains north of Santa Cruz, CA. Since the San Lorenzo runs almost due north/south (rare in California’s coastal range) southern storm winds lift moisture up the valley increasing rainfall with altitude. This is known as orthographic enhancement. In fact, places like Boulder Creek located up the San Lorenzo drainage can receive an order of magnitude more rain than Santa Cruz which sits at the mouth of the San Lorenzo river about 15 miles to the south.