Wednesday, February 2, 2011

Storm-Force Gusts Hit the Northwest Today!

You thinking I am kidding don't you?

I am not.

In one part of the Northwest winds gusted above 70 mph today. You could have driven there and enjoyed a wonderful view too...if you didn't blow over first. The fact that one part of our region could have severe winds while most of the rest of us are enjoying sun and light winds is one of the marvels of living here.

The location? Crown Point overseeing the Columbia Gorge

The Gorge is not only startlingly beautiful but its meteorology is fascinating. It is the only sea-level gap across the Cascades. So if there is a large pressure difference across the Cascades air tends to accelerate down the Gorge from high to low pressure. In the winter, this generally means wind blowing to the west since in this season we often have strong high pressure areas inland and low pressure along the coast or offshore.

You have heard about the super cold air to our east--most of it is east of the Rockies, but some has drained into eastern Washington. The cold dense air east of the Cascades is associated with high pressure...much higher than over the west side of the region. The result--one big pressure difference! In fact, the pressure difference between Portland and The Dalles (east of the crest in Gorge) got to over 8 millibars this morning, which is quite large. And the big temperature difference across the mountains also helps to rev up a westerly Gorge flow.

Here is the pressure and temperature 12-h forecast for 4 AM this morning--you can see the cold air (blue) east of the Cascades, and a large number of isobars (lines of constant pressure) near the Cascade crest.
Mark Nelson, the Chief Meteorologist of Fox 12 in Portland (and a UW Atmospheric Sciences graduate!) and Oregon State Parks have put weather sensors at Vista House, the beautiful historic building that sits on top of Crown Point. This is great location to catch the winds and today its got hammered. Here is a sample of the observations:

Sustained wind in the 40s (mph) and gusts to 70! With temperatures around 30F we are talking serious wind chill (like 10F).

Want to see a video about how bad it can get at Crown Point?

Click on the image and beware of nightmares tonight:


or this one, where the reporter almost get blown away (click here)

The weather will decline a bit starting mid-day tomorrow, with some light rain on and off into the weekend, but next week guess what? ANOTHER big ridge develops in the eastern Pacific and we dry out AGAIN. Pathetically little snow from these weak systems. No floods. No real winds. No real nothing.

9 comments:

bhd said...

Nothing but that irritating sunshine? Jeez Louise. You'd think it was August.

Wx Enthusiast said...

Yea that video shows how bad it can get in the Gorge - all that sun!! Thanks for bringing the improving weather tomorrow through the weekend, but sorry to hear about yet another ridge next week. Is sun becoming much more common in the winters here, or does it just seem that way?

When you get some time, are you able to explain the spike in temperature at the airport at 3pm today? Does it have anything to do with the light westerly breeze from the Sound at the same time? It went from 47 at 2pm to 58 at 3pm back to 45 at 4pm.

Michael Dempster said...

Cliff, can you think of anything in our experience with pressure to help us get a better sense of the pressure differences you describe here? For example, how does it compare to the difference in pressures inside and outside an average balloon? The pressure difference experienced in going up a chair lift 1000 feet? Swimming down three feet? Puffing out your cheeks? Blowing out a candle?
Thanks!

Peter said...

I love that video with the reporter.

The GFS has been consistently (last couple of days) showing a significant change in the jet stream pattern we have been stuck in for close to a month. Is this what people mean by the longwave pattern? Is there good reason to hope that this is really going to come about by the end of next week after one more ridge? Thoughts?

Lindsey said...

But some of us want at least some semblance of a more typical La Nina winter here in the Pacific NW, bhd. And the latest 8-14 day outlook (http://www.cpc.ncep.noaa.gov/products/predictions/814day/) suggests a significant pattern shift happening around next weekend or so, with forecast confidence being "above average." I've gotta think that one of these times these longer range forecasts are really going to pan out for us . . .

Dom said...

I saw this and I thought you'd want to see it, a reader has a question for you about clouds in Bremerton.

http://www.flickr.com/photos/mtngrl/5414315536/

Foot's Forecast Northeast PA said...

Hey Guys,

Love your stuff! It's very interesting to learn about Northwest weather. I have a young group of weather forecasters from the Northwest opening up a page on facebook. I'd appreciate if you guys could take a look http://www.facebook.com/pages/AnalystWxCast-Pacific-Northwest/161174760601863

Thanks,

Andrew

Teresa said...

With the mild weather, the mosses are going absolutely NUTS in mountain/foothill transition zones. With the emerald green mosses and and the incredible silty blue waters, the forests are unbelievably beautiful right now.

Kevin Purcell said...

Michael Dempster said "Cliff, can you think of anything in our experience with pressure to help us get a better sense of the pressure differences you describe here?"

8mb is the pressure exerted by of an extra 230 feet (or so of air) i.e. if you ascend from mean sea level to 230 feet the pressure will drop by 8mb.

If you go 3.2 inches under water surface the pressure will increase by about 8mb.

The pressure difference is much lower than in all the examples you site.