Isolated to scattered thunderstorms may produce dangerous lightning, gusty winds, hail and brief heavy downpours, impacting outdoor activities and recreationists. Cool temperatures into next week. Thunderstorm chances continue for the mountains and northern Sacramento Valley.
Discussion
Clear to partly cloudy skies cover interior NorCal early this morning as debris cloudiness lingers from Thursday evening’s deep convection. Robust onshore flow and a deep marine layer (over 3k ft on coastal profilers) are allowing marine stratus to once again extend well inland, and Travis AFB is already reporting a low ceiling. Low clouds will likely make it back into the Sacramento area before sunrise. Current temperatures are similar to those from 24 hours ago and range from the upper 30s to lower 50s in the mountains, to the mid 50s to mid 60s in the Central Valley.
The upper trough will remain over NorCal into next week. The first batch of energy exits to the southeast today with short-wave ridging briefly moving in tonight and early Saturday before another closed low drops southward later Saturday into Sunday. The result will be a continuing threat for late day showers and thunderstorms into next week. Storms will mainly initiate over higher terrain, but will drift down into portions of the Sacramento Valley (mainly the northern half) in the evenings. Brief heavy rain, occasional lightning, gusty winds and some hail will be possible with stronger storms.
Temperatures will remain near to slightly below average through the weekend into early next week. Rivers and lakes are still running fast and cold from snowmelt, so avoid them!
Extended Discussion (Tuesday through Friday)
Models differ with placement and progression of short waves, but agree that upper low/troughing will continue through the extended forecast period. This will result in near to slightly below normal highs next week, Afternoon showers and thunderstorms will continue to possible each day, mainly over the mountains.