Rain and low-elevation snow into Wednesday with major travel impacts. Difficult to near impossible travel in the mountains through early Wednesday. Thunderstorm chances this afternoon into early this evening. Cold and drier mid to late week, with another storm system arriving over the weekend. Hard Freeze Warning in effect from 2 am to 8 am Wednesday and Hard Freeze Warning in effect from 2 am to 8 am on Thursday.
Discussion
Mainly dry conditions have set in over the region with mountain snow showers continuing. This period of dry weather will not last long as our next short wave is starting to push into northwest CA. This will bring the return of widespread showers to the region along with heavy mountain snow. Showers will overspread northern areas before daybreak with them continuing to develop south during the morning and early afternoon hours.
Shower chances will gradually diminish in northern areas during the afternoon and evening but will linger longer in southern areas as the trough axis slowly works south. Snow levels are between 1000 and 2000 feet for most of the area but are locally down to 500 feet over Shasta County this morning. Redding has a similar temperature as yesterday but does have a lower dew point resulting in a lower wet bulb temp. All this to say we may see some snow mix in in the Redding area as showers push in this morning. Accumulation looks to be limited with maybe up to 1″ in far northern and western parts of town.
Snow levels rise above 1000 feet in Shasta County by the mid morning. Snow levels will come up some in the Sierra during the afternoon too rising to 1500-2500 feet. Snow rates later this morning through the afternoon could once again approach 2-4″ per hour.
Several more feet of snow is expected again today and travel will remain near impossible over the mountains. Models show some CAPE building in this afternoon mainly over the Sacramento Valley. With skies remaining mostly cloudy today it’s unclear how much CAPE we see and this should keep thunderstorm chances isolated.
If we happen to see thunderstorms develop small hail will be the main threat with them. 0-1 km shear is marginal around 15 knots but should be enough for a spin up if we see any stronger cells.
Breezy southerly winds develop again this morning into the afternoon. Wind gusts 20-30 mph for most of the Valley with gusts as high as 40 mph for the Oroville and Chico area. Gusts as high as 60 mph over the Sierra will keep blizzard conditions in place into tonight.
The upper level trough will push south and east on Wednesday ushering in quieter weather. A few showers will linger over the Sierra early on but should diminish by the early afternoon.
We will see a cold start to the day Wednesday with Valley temperatures in the 30s. Short wave ridging will bring clearing skies Wednesday night. This will result in even colder low temperatures with mid 20s to lower 30s in the lower elevations. A fresh snow pack will bring single digits to the mountains.
The short wave ridge will flatten on Friday as long wave troughing begins to push into PacNW. Things will remain dry on Friday with the return of precip over the weekend.
Extended Discussion (Saturday through Tuesday)
Unsettled weather is likely over the extended period as long wave troughing sets up over the West. This will bring multiple chances for rain and snow to the region. The first chance looks to come later Saturday into Sunday with additional chances into early next week. Exact timing of higher precip chances is uncertain but wet weather is likely.
Lower snow levels will remain in place with them starting out 2500-3500 feet Saturday falling to 1500-2500 feet Sunday.
Several feet of snow is likely over the Sierra. If you have mountain travel plans you should plan ahead for difficult travel.