Stormy Friday brings rain, wind, ice to lowlands and messy wintry mix to passes
SEATTLE -- A stormy day has brought heavy rains and gusty winds in the lowlands, and a wintry mess of snow and freezing rain in the passes and to parts of Whatcom County.
Winds will be the most noticeable factor in the lowlands Friday evening as an area of low pressure moves through the region.
A Wind Advisory is in effect for the interior from the Snohomish-Skagit county line south to about Toledo from 6 p.m. through 4 a.m. Saturday for southerly gusts to 40-45 mph. Also included in the advisory are the coast (gusts to 50 mph), the San Juan Islands, and Island County.
Once the storm center passes, it will draw a surge of westerly wind down the Strait of Juan de Fuca late Friday evening/early Friday night that will bring a brief burst of winds to 40-45 mph to the northern Olympic Peninsula, Whidbey and Camano Islands. Thus a Wind Advisory for more of a westerly wind to 45 mph is in effect there.
Elsewhere, it'll still be a windy evening/night but wind speeds are expected to remain below the 45 mph minimal requirement for a Wind Advisory.
Wind is expected to peak around 6-10 p.m. then taper as the night progresses.
Up in the mountains, a Winter Storm Warning remains in effect for both Snoqualmie and Stevens Pass through 10 p.m. for as much as 8-12 inches of new snow -- Stevens will get the heavier snow totals -- and up to 0.2 inches of freezing rain accumulations with greater threat of highest freezing rain accumulations at Snoqualmie Pass.
Generally, snow levels are around 5,000 Friday, but in the passes, it continues to be a battle between the warm air coming in with the storm drawing in a frigid east wind from Eastern Washington through the mountain pass gaps. The snow aloft melts in the warmer air, then freezes into ice when it encounters that arctic wind blowing along the surface. Weather conditions may fluctuate between snow, freezing rain, sleet and just plain heavy rain as the winds ebb and flow and mix the cauldron of air above, but all of them present travel challenges.
The wintry mix there will continue through the day, then change back to snow overnight Friday as snow levels fall to around 2,500 feet after midnight amid snow showers. It will also be quite windy up there as the snow levels fall with potential gusts to 40-50 mph in the late evening/early nighttime hours that could make for blowing precipitation (rain/freezing rain early, snow late although as it changes to snow, winds will be slowly decreasing). Suffice to say, not a fun Friday in the passes.
Also staying with the wintry mix are the inland areas of Whatcom County, where a Winter Weather Advisory has been upgraded to an Ice Storm Warning and extended until midnight. Cold air from the Fraser River Valley is still trickling into the Sumas, Ferndale and Lynden areas for additional freezing rain. The ice storm is causing power outages in Lynden and Sumas. Driving conditions from Ferndale to Lynden to Sumas can be dangerous.
Don't forget the rain
With the relatively high snow levels and heavy rains, some rivers may experience minor to moderate flooding. A Flood Warning is now in effect for the Newaukum River for moderate flooding likely. Flood Warnings are also in effect for the Snoqualmie, Skokomish and White Rivers for minor flooding. A Flood Watch is up for all other mountain-fed rivers in Western Washington except for for rivers in Whatcom and Skagit counties where snow levels will be lower.
We calm down Saturday and then enter a tranquil weather pattern for the first week of 2018.