Weather Blog

Northwest getting hit by virtual ''anti-wind storm''

Northwest getting hit by virtual ''anti-wind storm''
A layer of fog hangs over Seattle on Oct. 20, 2013. (Photo courtesy: Puget Sound Clean Air Agency Visibility Camera)

Missing: Isobars. Last seen about a week ago...

The last part of October is the traditional start of the stormy season in the Pacific Northwest.  But Mother Nature is going in the totally opposite direction, bringing what you might call an "anti-wind storm" -- a wide swath of area that will not have *any* wind.

Wind is caused by differences in pressure -- air flows from higher pressure toward lower pressure. On weather charts, the pressure is noted by isobars, and around this time of year, we are eagerly counting the of isobars around because the more there are and the closer together they are, the windier it'll be...

like this forecast model for our windy day back in late September -- lots of isobars! (It turned out not to be quite this bad, but just to show worst case scenario)

But take a peek at this chart for Thursday -- something I don't think I've really seen, or at least noticed, before:

Note there is not a single solitary isobar stretching from about Juneau, Alaska to Eureka, California. Each black line denotes 4 milibars of pressure so the lack of any isobars on this chart says, essentially, the pressure is the same across the Pacific Northwest. All of Washington, Oregon, Idaho and just about all of Nevada, Utah and British Columbia are in the pressure group (The red dotted lines are a temperature measurement.)

That means no wind anywhere and very stagnant conditions -- the anti-wind storm! -- and a continuing dose of dense fog, especially at night in and in the mornings with nothing to mix things up.

And here is the result: Lots of fog -- at least around the Puget Sound area:

But if you crave some sunshine -- it can be found! Just head up above the fog layer. Sunday afternoon, it was a chilly 51° in the dense fog in Seattle, but it was several degrees warmer at normally-colder locations up high.

Paradise Ranger Station was at 63° (camera below) while Snoqualmie Pass had hit 64° and Stevens Pass reached 61°.

While that forecast model map shows expected conditions for Thursday, there really isn't much change from now through then... and even after, those stagnant conditions hold through the rest of the month and look like it'll even last into the first few days of November. Certainly not what we we're expecting this time of year!