Cool and unsettled weather continues today. Scattered showers and thunderstorms are possible with snow showers over the mountains. Dry and warmer weather returns beginning Wednesday.
Discussion
Radar shows a few showers continuing early this morning over Tehama, Glenn and Butte Counties, just to the east of the center of the cold closed low. Skies are clear further south over the Central Valley while mostly cloudy conditions persist over the northern Sierra. Current temperatures are mostly a little cooler compared to 24 hours ago and range from the 20s in the mountains to the upper 30s and 40s across the Central Valley.
Another day of unseasonably cold temperatures (highs around 15-20 degrees below average) along with scattered showers and a few thunderstorms lies ahead for interior NorCal. The low will drift slowly south to near the Sacramento area this afternoon. Similar to Monday, some of the stronger cells will likely be accompanied by brief downpours and abundant small hail. Over the higher elevations, occasional snow showers may lead to intermittent travel impacts across the passes with a few inches of snowfall accumulation possible.
The trough moves off to the south and east on Wednesday with dry and milder conditions expected to return to much of the area as short-wave ridging moves in. A few wrap-around showers may linger across the Sierra south of Lake Tahoe.
Another trough is forecast to move through the PacNW on Thursday bringing a chance of showers as far south as the northern Sacramento Valley and northern mountains, but will otherwise have little impact other than bringing renewed southerly breezes. QPF will be light with perhaps a tenth of an inch north of Redding.
Behind that system, ridging will begin to build for the end of the week leading to significantly warmer temperatures. Highs will return to the lower to mid 80s across much of the Central Valley on Friday.
Extended Discussion (Saturday through Tuesday)
Clusters continue to indicate upper level ridging influencing NorCal this weekend into Monday, although continued uncertainty exists with the amplitude and exact placement of this feature. Latest NBM guidance has decreased high temperatures slightly for this weekend, with Valley highs peaking on Saturday into the low 90s and into the upper 80s on Sunday. This seems consistent with EFI indicating above normal temperatures, but no extreme deviation with respect to model climatology. Dry weather persists in the extended period.