September 23, 2011

Sweating in the Pacific Northwest

 Note:  I made some changes to the html code that should make the blog work far better for IE9 browsers.  Let me know if anyone is having problems with performance of this blog on any browser...cliff

Bicycling to work today, I found myself wiping the sweat from my brow as I entered my building.  It really felt like the East Coast during summer out there. In fact, the last few days we have had some unusually humid air over the region, with nighttime minimum temperatures far higher than we are accustomed to.    The dewpoints were quite high this morning...rising into the mid-60s in some locations.   In fact, during the past day we have had the most humid air of the summer invading our region.  What is going on?

During the past several days we have had a pattern with unusually high pressure to our southeast and low pressure to our northwest (see graphic at roughly 18,000 ft--500 hPA pressure).   The result is a strong current in the lower to middle atmosphere from the southwest extended well back into the subtropics.  A flow that effectively transports moisture into our region.

 Here is a graphic showing the total water vapor in a column of air over the NE Pacific this morning--you see the current of high water vapor values heading our way from north of Hawaii?   This is often called an atmospheric river.

This river of moisture has been mainly directed into Vancouver Island and central BC and they have had very large amounts of rain this week.   You can also see the current of moisture--at least the part associated with clouds--in the visible satellite image this afternoon:

We have been just on the southern side of most of the clouds and rain, but within the current of higher than normal moisture.

With a current of warm, moist air coming towards us, our temps have been above normal and with the humidity our low temps have been WAY above normal.   Water vapor is very active in the infrared--in fact water vapor is the most important greenhouse gas in the atmosphere.  Such gases tend to warm us up at night--- they intercept the infrared radiation leaving the earth and reemit some back down to the surface, thus lessening cooling.  There is a reason deserts are cool at night--not much moisture.

Take a look at the temperature plot for the last week:
 See how high our minima have been the last three days? 10-15F above normal!

In short, we have been in the sweet spot--on the southern edge of a plume of warm, moist air.

Tomorrow will be the last day of the semi-tropical warmth, with temps getting into the lower 80s in places.  And the pattern shifts and we will have rain on Sunday and clouds/rain for much of the next five days.....

well...autumn did begin today.

Dog Update
   Still looking for my little cockapoo Leah.   My family is convinced that someone has picked her up in the area near the intersection of  105 N St., Holman Rd, and Greenwood Ave N.  Here is the area:

If any of you live in this area, please keep your eyes out for her (see link on right for pics). Let me know if you see anything.

 Seattle School Board Candidate Events

There are two important gatherings to listen and talk to Seattle School Board candidates:

Wednesday, Sept 28th-7:30pm
The Stranger's School Board Candidate Debate
Town Hall - 1119 8th Avenue, Seattle
NOTE:  The event is FREE but tickets are required.
Click here for ticket information.

Friday, September 30th 6-8pm
West Seattle Meet & Greet Happy Hour with Candidates Marty McLaren & Sharon Peaslee (and I will be there too!).   Refreshments, of course.
TOPIC: Improving Math, Science and STEM in SPS
7020 18th SW (north of SW Myrtle)
Donations appreciated. - all are welcome


  1. "Storms" Photographs and text by Mitch Dobrowner:

    OK, totally off topic, but I just came across this and I'm sure someone will like it. Hint: Select the "slideshow" option.

    I come from weather country. Maybe I should say Weather Country. Or add a lot of!!!!

    Anyway, a place where the weather can kill you dead any day of the year, before you even know it's after you.

    I kind of miss it too. (Not the kill-you-dead part though.)

  2. I'm not complaining. It will be cold soon enough!

  3. What are the chances the rain will hold off for a bit on Sunday, Cliff? Wondering whether those of us running the Bellingham Bay Marathon that day will be soaked by precipitation in addition to sweat!

  4. I have a weather station and what really amazed me was that on Friday my weather station recorded the warmest day of the year, on the first day of fall. I live west of Mt. Vernon and for the very first time this year we hit 80 degrees. We also had a low in the morning of 68 degrees while Mt. Vernon's low was around 70.

    Those lows were even warmer than the ones we had two years ago when it reached 96 degrees here.

  5. Thank you for explaining this unusual weather pattern. My wife wanted to to to Hawaii this winter so this might have saved us a trip.

    Good luck finding your dog!

  6. I remember similar conditions almost exactly a year ago... are they an early stage of a La Nina ?

    (It was memorable since I spent a day digging out some irrigation & a day filling the trench back in)

    Luck to your little dog.

  7. Cliff, my husband and I were camping this week in the Alpine Lakes Wilderness (we did the Stevens to Snoqualmie section of PCT) and noticed the hot muggy conditions even over 5000 feet. There were some nice mountain breezes and then once in a while a blast of really warm air. A couple nights it never really cooled off, which is unusual.

    Anyway, camping up high and watching sunrise and sunset, we noticed that the clouds were moving very fast. It was quite a show, actually. The highest clouds did not move so fast, mostly what I would call the middle layer, but I am not an expert in determining cloud height. It did not seem particularly windy on the surface. I am guessing that this was due to the atmospheric river, does that a reasonable guess?

  8. Cliff - I live 107th & Grenwood Ave and walk my dog around this area all the time, Ill keep my eyes open for Cockapoo!


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