Today has sunbreaks, scattered showers, and mostly cloudy skies around western Washington. High temperatures will be in the low to mid 50s. A wave of low pressure pressing down from British Columbia is keeping rain showers over parts of the north Sound.
This evening, west/southwesterly winds will increase up Puget Sound 20-30 mph as a large weather system approaches northern Washington. The east slopes of the Cascades will begin to accumulate snow; Methow Valley, Conconully and Winthrop expect 4-8” of new snow with the incoming cold storm.
From the evening and into the overnight hours, a large upper low is sliding down from Canada will crash into western Washington bringing mountain snow (heaviest above 4,000 ft.) and lowland heavy rain showers and possible thunderstorms containing small hail, gusty wind and downpours.
Wednesday will likely be a stormy day at times while the temperatures fall into the upper 40s to low 50s for highs. The cold low will hover overhead and offshore maintaining cooler temperatures and plenty of showers through Saturday.
A winter weather advisory is in place for the Cascades beginning at 5pm today. Through the night cold air will drop snow levels to 4,000 feet with 4-6” of snow above that elevation. Snoqualmie Pass elevation is 3,000 feet, yet snow and rain mixing in at times will allow 1 to 3 inches of slippery snow accumulate by Wednesday evening.
Up to a foot should accumulate above 4,000 feet over the south Cascade range. Mount Rainier may measure a foot of new snow by Wednesday evening. Snow levels will lower down to 2,500 to 3,000 feet by Thursday morning. Showers will continue but favorable wind direction diminishes for heavy snow.
For the lowlands, Thursday, Friday and Saturday will have chilly morning low temperatures in the mid to upper 30s. Each day will have showers and sunbreaks with isolated thunderstorms possible again on Friday. The large upper low pressure will finally track away from our area for a start of moderating temperatures and drier weather on Sunday afternoon.