Weather Blog

Seattle's break from heat wave comes with a price for Central Washington

Seattle's break from heat wave comes with a price for Central Washington
The view from near Leavenworth, Wash. as the Chiwaukum Creek fire continues to burn. (Photo courtesy: Dominic Urbano, FallenLeafImaging.com, Leavenworth WA" Backlink to appreciated but not required.

Many of us in Western Washington are breathing a sigh of relief that our days-long stretch of 80-90 degree weather is coming to an end.

But one region's relief is another region's pain. The process that is cooling down Western Washington is wreaking havoc in Central Washington and the firefighting efforts over there.

Our building surge of marine air here is creating higher pressure in Western Washington while triple-digit heat and its rising air maintains low pressure across the surface of Central and Eastern Washington.

That large difference in pressure across the Cascade Mountains creates strong westerly winds that shoot through the Cascade gaps and across Central Washington. As of Thursday afternoon, the pressure was 11.5 milibars higher in Seattle than in Wenatchee -- very strong!

As a result, winds have been gusting over 35-45 mph across Chelan County, with Wenatchee recording a peak gust of 40 mph and Ellensburg reaching 43 mph. And as we saw already, blowing dust from a previous brush fire shut down parts of I-90 Thursday and is likely to blame for a 24-car pileup in Vantage that injured 11 people.

The DOT says blowing winds will keep eastbound I-90 closed until Friday and gusts are expected to remain in the 25-35 range through much of Friday before gradually tapering off as Eastern Washington cools and the pressure gradients relax.

And that will at least be the silver lining for firefighters dealing with the blustery winds -- it will lead to much cooler temperatures by the weekend with highs dropping into the lower 80s.