Updated Saturday 11:25 p.m.
After a bleak start to the ski season, the mountain resorts are finally picking up a heavy post-holiday coating of white. Pass travel will be difficult overnight, as 8 to 18" of snow falls over the Cascades through Sunday morning. For the lowlands, areas of rain will alternate with peeks of a starry December sky, and cooler air will start to take over; most spots along the I-5 corridor will drop into the 30s by dawn.
This chilly turn is just a taste of much colder air to come as we slide into the final stretch of 2014. Sunday will feature just a few lingering showers, and in spite of some nice sunny breaks, most communities will struggle to get too far past 40° by the afternoon. Weather for the Seahawks game? Partly sunny with just a slim chance for showers. Highs in the 40s at kick-off at Century Link.
Modified arctic air will begin pumping through the Fraser River Valley near the B.C. border Sunday night, and at that point, temperatures really begin to plummet. There won't be much moisture left to work with, but as the snow level drops to 300' by early Monday, a few of the foothill communities may see some very patchy, light snow. I'd say we have the chance for a few flurries at best--most of us won't see a single flake as the cold, dry airmass takes over.
Monday morning will be icy cold, and any wet pavement will turn slippery as lows drop to below freezing before sunrise. Blue winter skies by the afternoon will look inviting, but afternoon temperatures will stay in the 30s. Near the Canadian border, gusty NE winds pushing through the Fraser will blow in excess of 30 mph, and the wind chill readings for Bellingham and the San Juans will drop into the 20s.
Tuesday and Wednesday will feature beautiful sunny days and starry skies, but it will be very cold--lows will drop into the 20s downtown and teens in the outlying areas, and highs will barely crack freezing during the day. Out and about on New Year's Eve? It will be chilly and dry, with overnight lows again mainly in the 20s. Not bad for watching the fireworks over the Needle, but be sure to bundle up with the works of winter wear if you'll be watching outside.
We don't get much of a chance of moisture back until later Friday and Saturday, and as warmer air moves in, the precipitation for early 2015 will start as lowland cold rain rather than snow. However, more snow is expected in the passes and at the ski resorts, so that better-late-than-never ski season should be off and running!
Have a great morning, and Happy Holidays!
Meteorologist Shannon O'Donnell
The KOMO4 Forecast Team