Second Northern California storm of week to bring heavy rain, snowfall and gusty winds
The wettest of the two storm systems of the week in the Sacramento Valley and in the Sierra arrived on Friday with the main event expected to arrive Friday night.
This storm is tapping into an atmospheric river, a narrow plume of subtropical moisture to deliver heavy rain and snowfall at times.
Friday afternoon will see on and off showers but the heaviest precipitation is expected to be Friday night through Saturday afternoon. A good-soaking rain in the valley and foothills will be possible. Gusty winds will accompany the main front that moves in with gusts up to 50-55 mph in some parts of the Valley, and up to 55 mph in the Sierra.
The gusty winds and heavy rainfall will then make their way into the Sierra, turning to snow. This will create difficult to impossible travel conditions above 5,000 feet.
A Winter Storm Warning is in effect until 4 p.m. Saturday with periods of heavy snow expected and wind gusts reaching up to 55 mph.
A High Wind Warning is in effect in the Bay Area until 7 a.m. Saturday. Some North Bay counties are in a Flood Watch until 4 p.m. Sunday and the Sacramento Valley is in a Wind Advisory until noon Saturday.
If you had outdoor plans on Saturday, finding an indoor solution will be best as rain continues through Saturday into Sunday morning.
Power outages are possible. On Friday evening, more than 15,500 Sacramento Municipal Utility District customers lost power near the Sacramento Executive Airport. SMUD anticipated power to be restored around 6:30 p.m.
Be prepared for winter travel if your weekend plans take you over Sierra passes. Chain controls, delays, and closures are possible.
Caltrans held westbound I-80 in Truckee due to multiple spinouts despite chain controls from Truckee to Baxter. Eastbound was still open but with chain controls from Cisco to Truckee.
Showers begin to taper off by Sunday morning, leaving Sunday afternoon dry across the valley and most foothill locations. A few lingering snow showers will be possible across the Sierra after sunrise.
The remainder of the weekend stays mainly dry before we're eyeing another quick storm system by Monday.
Storm totals
The two storm systems this week will help keep us on track to hitting our snowpack and water goals by next year.
We could see some spots in the Northern Sacramento Valley reach 1-2 inches of rain, whereas closer to Downtown Sacramento up to 1.5 inches of rain is expected. The UC Berkeley Central Sierra Snow Lab reported 12.2 inches of snow since Wednesday, and nearly 9.5 inches of snow since Thursday morning.
12/13/24 8:45am Update:
— UC Berkeley Central Sierra Snow Lab (@UCB_CSSL) December 13, 2024
24 hr ❄️ -- 9.4" (24 cm)
48 hr ❄️ -- 12.2" (31 cm)
We have flurries but higher snowfall rates should move in later this afternoon/evening. Heavy snowfall should continue through tomorrow with additional accumulations of 2-3 feet.#snow #CAwx #CAwater pic.twitter.com/vCwlqZBzu2
By Sunday, expect 1-3 feet of additional snow across elevations above 5,000 feet, with more than 40 inches around higher peaks.
Next week's storm chances
One more storm system looks to slide in as we start next week. Early models show this moving in as early as Monday morning, producing more scattered rain showers and more snow across the Sierra through Monday night.
This storm will be weaker than the one over the weekend and fast-moving like Thursday's storm. We are expected to dry out by Tuesday and Wednesday with partly cloudy skies and highs in the upper 50s through the afternoon.
After Monday, our pattern dries out again through mid-week, but another storm or two could be possible toward the following weekend.
Monday's storm timing and amounts are expected to change over the next few days so make sure to stay with the CBS Sacramento First Alert Weather team as we iron out the details.