July 27, 2009

Major Heat Wave and Possible Record

Today is running 7F ahead of yesterday, which got to 89F. It is clear that temps will get into the lower to mid 90s around the region today. Our most skillful tool for predicting temps...probcast..is now forecasting 102 for sea tac on Wed...this would be the all time record for any date in any year. Above is the probcast forecast for the max temps on Wednesday (you can see it yourself at www.probcast.com. The purple colors indicate where temps should be higher than 97F). Amazingly, this heat wave could last into the weekend (although the temps should modify a bit on Friday into Sunday, but still in the 80s). And remember, it will be hotter in Portland and the Willamette Valley, where temperatures well into the 100s will occur.

The heat wave is made worse by the high dewpoints today. Many locations are in the sixties, some in the upper 60s and near 70F. Dewpoint is a measure of the absolute amount of moisture in the air..we are usually in the lower 50s in the summer. High dewpoints keep nighttime temperatures up--which makes a heat wave much worse.

In short, we are about to enter an historic heat wave for our region. One day, your grandchildren will ask you... did you really experience the temperatures of July 29th, 2009? What was it like? How did you survive it?


  1. Thanks, Cliff. We're all in it together! Stay safe everyone! The week of lots of water, salads, sandwiches, and ice cream is here.

  2. the week before labor day in 1988 it was nearly 100 in centralia. I remember since it was the week before i was married and i was praying for it to cool off!

  3. Actually during a heat wave is when you want to avoid heavy foods like ice cream, as appetizing as it sounds.

  4. I remember the 1988 heat wave. I was camped out at Scenic watching trains coming thru the Cascade tunnel. It did reach close to 100 up there for that Friday and Sat of the weekend. Then the marine push came in Labor day and really cloudy and cool. August 1981 was a hot year too.

  5. 90 degrees already in Maple Valley.

  6. 90 degrees in Lacey as of 12:55pm.

    Predicted highs 92 on Wunderground, and 94 on Weather.com for today.

    Probcast predicts 95.

    We'll see.

  7. I officially blame Mayor Nickels for the heat wave.

  8. Will we see an aggressive marine push at the end of the heat wave?

  9. How does one get SeaTac's temps on probcast.com? I tried seatac, sea tac and 98158, and all I got was "?"s. But I was impressed enough with their predicting 97 for Mountlake Terrace, where I live, for Wednesday. And speaking of the Willamette Valley, Eugene, the area I'm from originally, already at 97 at 2 p.m.

  10. Dr. Cliff-

    What is to explain on a macro level the snow we had last winter and the stratospheric temperatures we are experiencing presently and will experience until friday?

    - Bert

  11. Lindsey
    I was just poking around the Probcast site too and thought I'd try the same thing you did. If you enter the zip of 98188 you will get predictions for SeaTac. It looks like 98158 is specific to the airport itself and maybe that info is not available to the Probcast? That's my guess.

  12. In the low nineties at Snoqualmie Pass? WOW.

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  14. Thanks, WeatherNerd! I guess I'd like to know what kinds of limitations it has in general. Like, is it only for the state of WA, or western WA, or what? . . .

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  16. Lindsey, if you look at the map on the website, you can get probcast forecasts for anywhere shown on that map (either by entering the ZIP code or clicking on the map). So that includes Washington, most of Oregon, western Idaho, and extreme southern BC.

  17. I just hope my grandkids are asking that, rather than saying, "You guys thought you had it hot back then, that was nothing!"

    P.S. Cliff, did you goose up the colors on that chart? It looks positively charred compared to the one on probcast.

  18. Here's Bellevue:
    Downtown Portland, OR:
    Port Townsend, WA:
    http://preview.tinyurl.com/PtTownsendProbcast (whine: I want to go there!)
    Snoqualmie Pass, WA:
    Enumclaw, WA:
    Friday Harbor, WA:
    Vancouver, WA:
    Blaine, WA (just over the border from Canada):

    It seems like the Eastside actually has some of the highest predicted temps other than the Portland area.

  19. 98074 Sammamish - 97 at the moment, and we have a few hours until sunset left...

    it's NOT a dry heat, tho :)

  20. It's hot here in Ft Lewis -- didn't spin the weather today but we're definitely on the lookout for wildfires. I'll be outside pretty much all week. Drank 3 l of water today alone!

  21. So, why is it that a couple of sites (weather.com, intellicast.com) are now showing lower temps on Wed than they were a day ago? Both of those sites are showing 90-91 for Wed highs. That is not even in the low end of the probcast.com range.

  22. 38°C/99°F right now in downtown Issaquah - from my unofficial measurements and also at the City web site


  23. Driving south through the East Side this afternoon, my car's thermometer said 91 in Bothell, 96 in Kirkland, 99 in Bellevue, and 96 in Renton.

  24. i got married late may ('02) in death valley (although at 8am). you'd think this sort of thing would be peachy, but no. good grief, i'm hoping prob cast is off by at least 10 degrees. should've gotten that little a/c unit before they all sold out...

  25. Chehalis hit 99 at 6pm Shelton was 98 Olympia 96

    Kelso was 100

    Portland area was 102

    Those are the highs are the westside We actually matched or beat by 1 digit the eastside of the state 99 was the high at Hanford.

  26. I was in Southern BC Saturday night and can tell you it was one of the most phenomenal storms of it's type I have experienced anywhere! Thunder and lightning with intermittent torrential rains lasted for hours with some Very Close and Frequent strikes at the peak. I was backstage at the Mission Folk Festival and had just met someone who shared a lot of acquaintances with me. We clapped hands in a high-five and in that moment there was a tremendous, nearby and fantastically bright and intricate bolt of lightning and near simultaneous explosion of thunder. This initiated a spate of flooding rain and many nearby strikes which closed down the stage show but made for a very energetic backstage jam session once the storm passed!

  27. Hey Cliff, how accurate are surface temperatures depicted on the 4km WRF-GFS? I'm trying to digest the 5am Thursday morning forecast surface temperatures from this very model at that time [http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d3/tsfc.72.0000.gif] ... and why they are so warm!! Low 80s at 5am across much of the Seattle Metro area? I can hardly believe that.

    I have a good feeling we're going to break the record for highest low temperature ever in Seattle this week, and have a feeling we'll tie or break the all-time high on Wednesday, but low 80s?? I'm having trouble trying to figure out why the model is giving these, so if you can help at all, that would be great!

  28. oh, and Cliff, that's obviously from the 12z run; the link may point to the 5pm Thursday temps if the 0z run has come in - but you know that.

  29. I'm headed down to Texas where DFW is predicted to top out in the low 90s this week. Who'd a thunk it, that I'd need to go to Fort Worth in July to cool off!

  30. Jeez, and I thought I had escaped Houston weather by moving up here :)

    Maybe we should start making Central Air more standard.

    Unfortunately many people consider it a waste of money, until the heat arrives :)

    Right now I've got two portable ACs, one for my bedroom and one for the rest of the house. At least I can sleep okay.

    I feel bad for my friends up here. At least in Texas they have AC, but most people here don't, except maybe at work.

    If the NW is so prosperous and technical, why can't they afford AC's? There's a lot more wasteful luxuries that people spend on all over the country, which have nothing to do with comfort. An AC doesn't cost much if you don't actually use it, so the argument that it's not needed often doesn't invalidate its utility.

    Like someone said, avoid heavy foods when it's hot. Drink hoppy NW beer, and eat spicy foods such as Indian.

  31. Would you buy a tractor because you might need one once a year? AC is mostly not needed here. It is standard in cars where it can be crucial.

    Open windows in buildings at night to allow cooler air to draft in. Close them in the morning to slow the loss of cool air. Use a fan to draw cool air from basements during the hot part of the day. Don't run dryers, ovens or dishwashers if you don't have to. You will survive...

  32. Lee, this heat wave only happens once every decade or so. People right now are probably hitting Lowe's and Sears to see if any A/C units are left but in few days the overnight mins should be more bearable. That is probably the biggest factor is whether one can sleep at night, most folks are at work in the day where it's either climate controlled or it doesn't matter.

  33. Thanks, Nicholas. Perhaps I should start using my eyes . . .

  34. Probcast wins...we hit 95 in Lacey...terrible.

    Muggy, hard to sleep, argh.

    Opening windows all night didn't even help it seems. Argh again...

    It seems we've had more "decade weather this, and decade weather that" over the last 5 years or so than I can remember in the previous 15 years combined.

    Does it all happen at once or something, sheesh. :)

    Stay hydrated everyone. Drink your morning cup of coffee, then ice water and salty snacks (not too heavy, trail mix etc...).

  35. Thanks, Cliff. But our grandchildren in Western Washington won't ask how we survived this. They will say "No big deal, we get temperatures like that all summer."


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