Dry and mild with above average temperatures through Wednesday. Widespread rain showers and mountain snow showers Wednesday evening through Thursday night. Additional mountain snow showers possible Friday into Saturday.
Discussion
A few high clouds continue spill south into NorCal as the frontal system and precipitation remains stalled to the north of the region over the PacNW. Current temperatures are running a bit cooler compared to 24 hours ago across much of the Central Valley with readings in the upper 30s to mid 40s. Mountain areas are mainly in the 20s and 30s with mid 40s in the ridgetop thermal belts.
Dry and milder weather will continue across the region today and Tuesday as upper ridging covers the area and the storm track remains to our north. Highs today will be around 4-8 degrees warmer than Sunday’s, and most areas will see a few degrees of further warming on Tuesday. Highs both days will be around 10-15 degrees above average, and a few records could fall.
By Wednesday changes are on the horizon with troughing forecast to impact the West Coast mid to late week. Confidence is increasing unsettled weather will bring rain and snow chances to interior Northern California by Wednesday evening.
However, there is some uncertainty still with exact timing as depicted in cluster analysis. Relatively warm temperatures into Wednesday will mean snow levels start out high on Wednesday, near mountain pass levels at about 6,500 to 7,500 feet.
Precip over some mountain locations may fall in the form of rain on Wednesday before changing over to snow overnight as temperatures decrease and the trough approaches. Southwesterly flow also increases on Wednesday with potentially moderately breezy conditions over the crest. Cool and unsettled weather forecast Thursday with the trough overhead. Models indicate potential instability, and may see a few thunderstorms across the Central Valley in the afternoon into the early evening.
Extended Discussion (Friday through Monday)
Another short wave progged to drop through interior NorCal Friday continuing unsettled weather with main threat of showers expected in the foothills and mountains. High temperatures Friday expected slightly below normal.
Weaker wave tracks through Saturday keeping a threat of showers over the Sierra Nevada. Drier and warmer weather expected Sunday into Monday.