Lowland rain and mountain snow through much of next week
seattle - A significant system offshore will bring lowland rain and mountain snow through at least Monday night. Let's talk about the rain first and then we'll get into the snow forecast. Tomorrow morning's commute is going to be a soggy one. Continuous rounds of rain tomorrow will be problematic for the Skokomish River in Mason County, where expected rain totals of 1-3" could lead to river flooding. The current forecast brings the river to a crest below flood stage tomorrow, but this could change!
The snow level will hover around 4,000'-4,500' today and Monday, so travel impacts look to be minor for Snoqualmie Pass as precipitation will mainly be in the form of rain. But above 4,000' like Stevens Pass and White Pass, light to moderate snow could make travel difficult.
A Winter Storm Warning is in effect for the Cascades of Whatcom and Skagit counties until 4pm Monday. This includes the Mt. Baker Ski Area. Snow accumulation could amount to 25" above 4,000'. If you must travel, pack a flashlight, food, and water in case of emergency.
A Winter Weather Advisory is in effect for the eastern slopes of the Cascades until 10pm Monday. Prolonged periods of light to moderate snow can make travel difficult so take it slow and check pass conditions before heading out!
An Avalanche Warning is in effect for warning and advisory areas until 6pm Sunday evening. New snow and wind could produce large, deadly avalanches so avoid the back country.
Additional systems will bring rain through next Thursday. The rain will come in waves and there will be dry breaks, like Wednesday afternoon. We'll dry out by Friday and Saturday.
Have a great day!
-Q13 Meteorologist Grace Lim