It’s easy to spot on the satellite image; another storm is getting ready to pounce on Western Washington.  This will bring widespread rain in a matter of hours with heavy mountain snow starting this evening. 

We’ll stay mainly dry this morning with any showers light and scattered around the sound.  Temperatures are starting in the low 40s with patchy fog as you get out the door this morning.  Rain becomes widespread and heavy this afternoon, setting us up for a soggy evening commute.  Afternoon high temperatures are topping out in the upper 40s and low 50s; on spot with normal for this time of year. 

As rain increases for the lowlands, the mountains will see snow pick up tonight.  Skiers, snowboarders, and snowshoe enthusiasts will be happy to hear that a Winter Weather Advisory takes effect at 4 p.m. today for the Cascade Mountains.  It remains in effect through 10 p.m. Saturday.  During that time, 8 to 17 inches of new snow is expected.  Snoqualmie pass will initially start as rain or a rain/snow mix this afternoon before turning over to all snow later tonight. Expect possible delays if you’re driving through the mountain passes tonight or tomorrow.  

Once this front passes through this evening, the red “L” you see on the satellite map will be hanging over our area through Saturday.  That is a trough of low pressure… a cold pool of unstable air sitting on top of us.  This will knock temperatures back down into the mid 40s tomorrow with rain at times throughout the day.  

http://bcove.me/gtv2ihvy

With that low spinning over our area, moisture will continue to stream in with that very cold air aloft.  This is providing enough instability that an isolated thunderstorm cannot be ruled out.  Any thunderstorm or heavy shower may contain hail.  The best chance of thunderstorms will be along the coast.  Winds will also be gusty; peaking late tomorrow morning through the afternoon.  

This storm moves out Sunday, leaving us with only a few showers in its wake.  Sunday will be the drier day for your weekend plans. 

Have a great weekend! 

-Sam Argier, Morning Meteorologist