November 27, 2019 – Major winter storm will bring heavy snow, rain, and strong winds to the area with major travel impacts through the Thanksgiving holiday. Much cooler temperatures are in store for the week. Another winter storm is possible over the weekend.

Discussion

Active pattern will continue through Thanksgiving as the cold closed low lingers across the region as the surface low fills along the OR/CA border. Winds, while still gusty across much of the region, have come down from their peak Tuesday evening. The KSAC-KMFR gradient is still around 11 mbs, but that’s nearly half of what it was last evening when it peaked around 20 mbs!

With moderately strong upslope flow and steep mid-level lapse rates, moderate to heavy snow will continue over the west slopes of the northern Sierra today where travel conditions will remain difficult. Upslope flow is forecast to weaken this evening with a corresponding tapering of snow showers expected.

Elsewhere, scattered to numerous showers will continue today under the cold low. A few thunderstorms will be possible this afternoon.

A tapering of showers from the north is expected Thanksgiving into Friday as the low gradually meanders to the east. Northerly flow will develop in its wake setting the stage for a potential hard freeze across the Central Valley on Thursday night into Friday morning. At this point its looking like the coldest temperatures will be across the northern half of the Sacramento Valley where readings could dip into the mid 20s. Further south, enough cloud cover may hold minimums in the lower 30s across the southern Sacramento Valley south into the northern San Joaquin Valley.

A brief break in the weather may be possible Friday before the next system moves in over the weekend.

Extended Discussion (Sunday through Wednesday)

By Sunday, precipitation is expected to be ongoing as a system impacts the area this weekend continuing through early next week. Multiple waves of rain and snow are expected as a compact low makes its way down the west coast through at least mid-week. Snow levels will be on the rise Sunday ranging from 3-6kft in the morning, with the entirety of the CWA seeing higher snow levels around 6-7kft by Sunday evening.

The heaviest precipitation is expected to be Sunday morning with, although continued Valley rain and Sierra snow will continue through at least Monday, possibly extending into mid-week. Temperatures next week will rise back to near normal with highs generally in the mid to upper 50s in the Valley. Keep watching for changes with this precipitation forecast as models are struggling with the exact track of this compact, closed low.