A strong Pacific storm is spreading increasing rain to the lowlands and heavy snow into the Cascades and Olympics on Tuesday.
Travel conditions across the passes will deteriorate Tuesday and remain difficult through the night. Between 10 and 20 inches of new snow is likely to accumulate down to the 3,000-foot level (Snoqualmie Pass) by Wednesday morning.
The heavy snowfall will be accompanied by very strong ridgetop winds from the southwest sustained at 45 to 65 miles per hour with higher gusts.
This combined with a rise in temperatures will build up large areas of unstable snow (snow slabs) for a high avalanche danger in the Cascades and Olympics away from avalanche controlled highways and ski areas.
Several more storms will move through the state Wednesday and Thursday for periods of heavy snow with snow levels peaking out around 3,500 feet late Tuesday night or early Wednesday.
Cool easterly flow should keep the precipitation as snow for all of the ski areas except for a chance of brief rain for the Snoqualmie area bases late Tuesday night or early Wednesday.
Colder air begins to move in off the Pacific later on Thursday with the snowfall becoming more off and on. Snow levels will also fall dropping to 1,000 to 1,500 feet Friday morning.
However, the cooling may be short-lived as warmer temperatures may move back in over the weekend raising snow levels above 4,000 feet with a chance of more heavy snow or rain.
Over in Idaho, it looks like we will see some snow, including between 6 to 8 inches in Sandpoint.