TONIGHT: Mostly clear skies with bitterly cold temperatures. Expect lows in the low to mid 20's within 3-5 miles of the Sound, but in the teens farther inland. Also expect widespread frost on roads and sidewalks. Drive, bicycle or walk carefully!
Puget Sound Forecast: Mostly sunny in the morning; increasing high clouds possible during the afternoon, especially north of Seattle. A few flurries may fall during the later evening hours. No accumulation is likely. Expect highs in the low to mid 30's.
Coast Forecast: Increasing high clouds with flurries or light snow possible during the afternoon and evening hours. A few spots could see minor accumulations of an inch at most. Highs in the mid to upper 30's. Southeast winds 5-20 mph.
Mountain Forecast: Mostly sunny, though increasing clouds are likely over the Olympics during the afternoon and evening, and possibly a few flurries. Freezing level near 500'. Pass highs mid teens to low 20's. East winds to 10 mph.
Eastern Washington Forecast: Mostly sunny, except partly to mostly cloudy along/near the east slopes of the Cascades. Minor flurries will be possible in that area. Highs upper teens to mid 20's.
WEATHER OUTLOOK/LONG RANGE TREND:
Modified Arctic air has moved southward through both eastern and western Washington. Winds have now shifted to northeasterly over almost all of western Washington, which occurs as the cold air pours out of the Fraser River canyon. This movement of air had produced blustery conditions, especially north of Everett, but those winds have now largely decreased. The combination of light winds and clear skies will allow substantial cooling tonight.
Thursday is likely to begin mostly sunny, but then a weak weather system moving over the top of the ridge just off our coast could generate a few clouds and maybe a few flurries. I don't believe this will be likely until later Thursday afternoon or evening, and the area most likely to see flurries will be over the Olympic peninsula or the Washington coast. The chance for flurries over the interior is very small...and the potential for any accumulations virtually non-existent. However, as the low moves south from just off our coast toward northern California, it will bring another surge of cold air from the interior of Canada. That will lead to clearing, but also result in even colder temperatures. That surge will also likely lead to gusty winds along/near the west foothills of the Cascades-places such as Enumclaw, Black Diamond and North Bend. Gusts could reach 30 mph Friday. Our Friday and Saturday highs will struggle to reach the upper 20's to low 30's. Saturday morning will likely produce our coldest temperatures of the week, with lows mostly in the teens...and possibly single digits in some sheltered inland locations.
Another weak system moves over the ridge later Sunday for more clouds and a chance of a few flurries - again with no accumulations. By Monday a shift begins in the weather pattern as a weather system will begin to approach from the southwest moving underneath the high pressure. This will give us increasing clouds on Monday. Temperatures will begin to warm higher in the atmosphere but remain cold at the surface. It looks like precipitation will begin to move in later Monday night...and it could begin as snow in places. We should see enough warming on Monday for many areas, especially near Puget Sound to start as rain. However, places that tend to be colder or trap cold air (for example, northern Counties, Hood Canal) could start as snow or freezing rain. As temperatures continue to warm on Tuesday we could begin with a mix of wet snow and rain, but it should turn to rain even in the colder spots...especially by Tuesday evening. Beyond Tuesday, I believe we'll see rain near the Sound and snow in the mountains.
Jeff Renner / KING 5 Chief Meteorologist