Crazy weather set up. There is an inverted trough over the Nevada/Utah border, the high pressure center over Death Valley, and a MCS over Arizona. The different directions of the atmospheric flow overlapping each other is creating a deformation zone with very heavy thunderstorm activity. This should propagate into SW CA in the next few hours
From the NWS LOX: LAL of 6 for dry lightning SBC, VNC Mtns and SLO:Threat of thunderstorms Sunday into Monday morning Mix of dry and wet thunderstorms with limited rainfall likely Gusty and erratic outflow winds (wind gusts up to 40 mph possible) Increased risk of lightning generated fire ignitions with rapid fire spread due to very dry fuels - prompting Red Flag Warning issuance(LAL 6)
Slightly lower threat south in LAC and VNC valleys.
Surface based convection continues to bubble up and will transition to more of an altocumulus castellanus environment this evening as the upper level low moves into the area & interacts with thunderstorm complexes over AZ and Mexico.
This is an image of the geocolor with an overlay of upper water vapor imagery. You can see where the upper level low is and how it has evaporated and disrupted the marine layer underneath it… plus the drier air in the upper level low.