Rain and low-elevation snow into Wednesday with major travel impacts. Difficult to near impossible travel in the mountains Monday through Tuesday night. Winter Storm Warning until 4 AM PST Wednesday, Wind Advisory from 4 AM to 4 PM PST Monday, Blizzard Warning from 4 AM Monday to 4 AM PST Wednesday. (The last time a Blizzard Warning was issued for the NWS Sacramento forecast area was on January 26, 2021 for January 26 – January 29, 2021)
Discussion
Still a few light showers lingering across the region as were in-between systems with the big low now moving through SoCal and the next upstream system approaching northwest California early this morning.
With all the clouds and lingering showers, current temperatures are milder compared to 24 hours ago with upper 30s to mid 40s in the valley, and mainly 20s in the mountains.
The next system moves in this morning spreading light to moderate precipitation across the region. QPF will be generally less than a third of an inch in the valley with up to 1.5 inches over the mountains.
Snow levels will be around 2-3k ft with around 1-2 ft of additional snow expected over the mountains.
Southerly breezes will increase later this morning, but will be less than what we saw Thursday night and Friday morning.
A very brief lull is possible later today and tonight, then a couple of strong winter storms systems are expected to affect the area beginning very early Monday morning and continuing through Tuesday night.
Snow levels will be lower, generally 1-2k ft, but there will be another chance for snow across the northern Sacramento Valley on Monday into Tuesday.
Currently it’s looking like an inch or two for the valley floor north of Red Bluff with 4 or 5 inches possible along the western foothills and far north end of the valley including Redding.
A strong storm will bring dangerous to near impossible mountain travel on Monday and Tuesday with 2-7 ft of snow expected along with gusty winds to 60 mph or higher resulting in zero visibility in blowing snow.
This is a cold system with high ratio, 1:18 at times. Very high snow rates are possible, 3+ inches an hour Monday through Tuesday.
A Blizzard Warning has been issued for the northern Sierra and the mountains of western Plumas County and eastern Butte County for 4 am Monday to 4 am Wednesday.
Southerly winds will increase Monday with gusts up to 45 mph in the Sacramento Valley. A Wind Advisory has been issued for that area 4 am to 4 pm Monday.
Unstable conditions will bring the potential for thunderstorms on Monday and Tuesday. Small hail is the main threat.
The stormy conditions are expected to wrap up on Wednesday as the main trough shifts east and ridging builds into NorCal from the eastern Pacific.
Extended Discussion (Thursday through Sunday)
A ridge of high pressure will build over the region on Thursday, resulting in dry conditions, lighter north winds for the Valley, and cold morning lows. NBM projects near to slightly below freezing temperatures returning to the Valley Thursday morning, with lows generally in the upper 20s to low 30s.
The ridge looks short lived as a shortwave to the northwest begins to flatten the ridge on Friday.
Ensembles and clusters are in good agreement with another cold trough impacting the region next weekend. This will bring another round of Valley rain and moderate to heavy mountain snow.
Snow levels will be 1500-3000 feet. There is a 55-80% chance of 12 inches or more over the Sierra, so hazardous mountain travel conditions are possible.