Showers from today will linger overnight and the cooler conditions we experienced across western Washington today will carry again into tomorrow.
A trough to the north will sink south by tomorrow evening into Monday and with that will come more wet and cooler weather. The cooler air mass accompanying this next system will create some instability in the atmosphere so there is a slight chance for some thunderstorm activity across western Washington. With the cooler air also comes lowers snow levels (down to about 2,000′).
A Winter Weather Advisory will go into effect at 11 p.m. Sunday and remain in effect until 11 a.m. Monday. This advisory effect elevation above 3,5000′ and snow accumulation could reach up to 8″. For Snoqualmie Pass snow totals look lighter than Stevens Pass who could see between 5-6″ by Monday afternoon. Snow on the roads will also be lower due to warmer surface temperatures.
Temperatures will remain in the 50s for the rest of the weekend through the first half of the week. 60s return from mid-week into next weekend with some dry days mixed in between.
Another system piggybanks off the previous one arriving Monday night into Tuesday morning but most of the wet weather with this system seems to favor the southern half of the state.
Long range, looking ahead to the first week of may, CPC show near normal temperatures and above average precipitation.