Colder with lingering showers into Saturday. Near to below freezing morning lows Saturday morning and mid to late next week. Two additional systems will move through the area: Sunday and Monday – Wednesday (wettest of the two). This will bring widespread Valley rain and additional heavy mountain snow above 1500-3000 feet.
Discussion
The upper level low that has brought active weather to the region is starting to push down to the coast towards SoCal. We are still seeing widespread rain and snow from mainly Red Bluff south because of this upper level low. That will change as we head into the evening with activity continuing to shift south and things becoming lighter and more showery in our area. These showers will linger into overnight and into tomorrow morning from about I-80 south and will linger into the afternoon over the Sierra.
Snow levels are between 1500-2500 feet and will come up some this evening. Several inches of additional accumulation can be expected over the Sierra mainly above 3000 feet and mainly falling during the late afternoon and early evening. Additional accumulation overall will be limited tomorrow but we still could get a few inches over the Sierra. Additional Qpf in the Valley will remain around 0.25″ or lower.
Flow will become zonal later Saturday into Sunday ahead of a digging long wave trough. A short wave will track ahead of the long wave trough on Sunday and that will bring us a quick hit of rain and snow.
Precip looks to move into the Coastal Range and northern areas early Sunday and will continue to spread south during the day Sunday. Activity will move out Sunday evening into the overnight. Snow levels will this round will be mainly 2500 feet and higher with 1 to 2 feet of snow over the Sierra and 4 to 15 inches over the Coastal Range and Shasta County Mountains.
QPF looks to be 0.50-1.0″ in the foothills and under 0.50″ in the Valley. A few mountain showers will linger Sunday night with a wetter system moving in Monday.
The long wave trough will continue to dig and start to push east Monday and this will bring another round of widespread precip. Things will push into the Coastal Range Monday morning and work south into the afternoon.
Snow levels will generally be between 1500 to 2500. Heavy snow is expected over the Sierra with feet of snow possible. Mountain travel will be difficult on Sunday and will be near impossible by Monday afternoon. We will also see some instability build in during the afternoon on Monday and a few thunderstorms aren’t out of the question.
Breezy southerly winds develop ahead of the digging trough Monday with wind gusts 20-40 mph in the Valley and up to 60 mph over the Sierra.
Extended Discussion (Tuesday through Friday)
Long wave trough will remain over the West for the start of the extended period keeping unsettled weather in the forecast. Showers will continue over the region with rounds of widespread precip into early Wednesday.
Snow levels will generally remain between 1500-2500 feet but could fall lower Wednesday morning. Some of the cluster are slower in pushing the trough out of here and if we see that solution showers may linger throughout the day Wednesday. Mountain travel during this period will be very difficult and traveler should plan ahead.
We will also see some instability during the afternoons and that will bring an isolated thunderstorm chance.
By Thursday a ridge will build over the region to keep the area dry with lighter north winds for the valley. The ridge looks short lived as a shortwave to the northwest begins to flatten the ridge on Friday. A couple of days of dry weather looks good at this time.