Quick update this evening. This extended storm event is not over yet for Southern California. Though all major frontal boundaries have already moved through, a vast area of vigorous open cellular cumulus cloudiness is being directed into the southern half of the state from the west. With a nearly 200kt jet overhead, a nearly saturated atmospheric column, and increasingly cold air aloft (in addition to some directional wind shear), strong to severe thunderstorms have started to develop and move ashore from Santa Barbara down all the way south to Tijuana. 2 tornados have already been confirmed in the past week (and there may have been more), but I do expect at least a couple more before this is all said and done. Large hail and damaging straight-line winds have also been reported this evening. These storms have been producing relatively brief but extremely intense precipitation–up to 2 inches/hr. This, obviously, will lead to flash flooding under storm cores. Storms appear to be developing further offshore and clustering, per local radar, and the latest satellite imagery shows no sign of the convection abating any time soon. Severe storms may occur through the day tomorrow.
Heed warnings as they come: there really is the potential for some dangerous weather out there. As for Northern California: a few thunderstorms may develop tomorrow afternoon with daytime heating, possibly producing some hail, but severe weather appears unlikely at the moment in the north as the dynamic instability remains mostly over SoCal.