Rare August wind storm brings possible weekend power outages

SEATTLE -- Most of the kids haven't even gone back to school yet, and already we have our first autumn-type storm of the season.

A potent -- and apparently calendar-challenged -- storm is swirling offshore and is expected to roll into Western Washington on Saturday, not only bringing a heavy dose of rain, but wind speeds typically unheard of in summer. It's even prompted wind advisories for most of the region in a time when local forecasters can't ever remember issuing one before.

The storm will first be felt along the northern Oregon and southern Washington coast Saturday morning as the storm center approaches the shore. A High Wind Warning is in effect there from late Friday night through early Saturday afternoon for potential wind gusts of 55-65 mph(!) as far north as Long Beach, and a lesser Wind Advisory is in effect for the rest of the Washington coast for gusts to 50 mph -- that's slightly higher forecasted gusts than we had earlier Friday.

The storm will push inland into the Seattle Metro and I-5 corridor by late Saturday morning into early Saturday afternoon and then into the Northwest Interior. A Wind Advisory is in effect for the greater Seattle/Puget Sound metro area from 11 a.m. to 5 p.m., and it stretches from noon to 9 p.m. for the Northwest Interior for southerly winds sustained of 15-30 mph with gusts as high as 45 mph.

Those wind speeds are pretty routine for November and December -- this type of storm probably wouldn't even be a story on the home page of our website three months from now. But for August, 45 mph winds are quite rare, and have potential to do more damage than usual.

The trees are still heavy and full of leaves, and the first windstorm of a season tends to be the one to break off all the more susceptible branches that weakened over the summer. Thus, we tend to see more damage with lower wind speeds early in the season than in late fall and winter when the trees are bare, and it's a good idea to be prepared for scattered power outages in the midday and afternoon hours.

Usually we're talking about the first storm in October, but this year's been wacky in the weather department for the last several months so, why not a windstorm in August?

In addition to the wind, drenching rains will be a factor as well. Heaviest rains will fall early Saturday morning, with perhaps a brief lull in the mid-late afternoon when the wind kicks up, then a secondary wave of rain is expected in the evening. Winds and rain will call down Saturday night.

All told, much of Western Washington is expected to receive well over 1" of rain by Sunday morning, with some spots in the mountains getting 2-3 inches of rain. The National Weather Service says in the history of recorded Seattle weather -- which is back to 1891 -- there have only been 11 dates in August to have more than 1" of rain, and never two in the same year. We've had one day already this year at 1.50" on Aug. 14 when we had all those thunderstorms. Could another weather record fall this summer -- only this one would not be heat related?

Additional weather systems are expected to parade through the region Sunday into next week keeping rain in the forecast, although none of the storms will be as intense as Saturday's. If Seattle manages 2.16 inches of rain or more by Monday night (which will be a stretch), August 2015 will end up wetter than January 2015.

Eastern Washington to get rain, wind, blowing dust too

Some of the rain is expected to make its way into Eastern Washington, including where the wildfires are burning. Forecast models indicate about a quarter to half inch of rain out there -- a blessing for the firefighting efforts.

However, with the rain comes other dangers -- namely very strong winds. A High Wind Watch is in effect for much of Eastern Washington, including the Moses Lake, Spokane, Pullman and, yes, the Okanogan Valley and Highlands.

Gusts on Saturday have the potential to reach 50-60 mph -- except there are fears of 65 mph gusts in the mountains. A lesser Wind Advisory is in effect for areas closer to the Oregon border, such as Walla Walla, the Tri-Cities and the Yakima Valley for winds up to 50 mph.

The wind has prompted another Red Flag Warning to be issued in the area of the wildfires, meaning extreme danger for wildfire creation and spread.

In the basin, the strong wind is a recipe for major dust storms and a Blowing Dust Advisory is already in effect for just about all of Eastern Washington that's not in the mountains. Those with travel plans across Eastern Washington, including along I-90 and US-2 need to prepare for reduced visibilities, and those with high-profile vehicles need to be aware of strong, gusty winds.

All areas will calm down Saturday evening and night.
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