A low pressure system will just clip the Northstate to south Thursday morning. Wrap around moisture and cold air will allow for low snow Thursday.
A surface low will move in late tonight and into Thursday morning. Wrap around moisture will quickly overspread most of the Northstate by late morning. A cold northwest flow aloft will allow for snow levels to drop down to 2,000 ft and lower in isolated spots.
Snow showers will continue for the foothills and mountains through Friday morning.
Heading into Friday afternoon the warm front will quickly race north into Oregon, raising snow levels. Warm advection (overriding) precipitation will also help to rise snow levels.
By Friday afternoon a high precipitable water moisture plume from the sub-tropics (including Hawaii) will move in. A 1003 mb low will likely come ashore late Friday night, embedded in this warm tropical air-mass. The low, which will come ashore in southern Oregon will likely crank up the south and southeast winds Friday night and Saturday for most of the Northstate.
South and west facing mountain slopes will be able to see high rain totals thanks to orgraphic lift. The northern valley, including Redding, could see total rainfall at or above 2.00" especially western and northern Redding.
Snow levels will rise from 2,000 ft Thursday to over 6,000 ft by Saturday afternoon and evening.
Snow levels should remain at or above 6,000 ft through Sunday evening as precipitation exits south.