June 23, 2010

Finally! The 75F Ceiling is Broken

Today, temperature at Seattle Tacoma Airport has reached the the magic number--75F-- in fact later this afternoon temperature climbed to 77F. This is the latest into the summer season that Sea Tac has reached 75F for the first time. As apparent in the high resolution visible satellite image below--a clear zone existed today over western Oregon and Washington. Offshore extensive low-level cloudiness was in place, while eastern Washington was generally cloud with some convective showers over the northern portions.

Significant pressure changes have occurred during the past several hours, with the onshore pressure gradient reversing: pressure is now higher on the coast than inland, and some cooler ocean air will move in. Tomorrow will not only be cooler, but there will be considerable clouds and some light showers over the region.

I have gotten a large number of comments suggesting that the Iceland volcano has been the cause for our cool weather. Let me be absolutely clear on this...there is no reason to think this is true. None. The continuing eruption is NOT putting large amounts of sulfuric acid aerosol into the stratosphere---which is the only way that volcanic eruptions can have climatic impacts. Remember--Mt. St. Helens had virtually no climatic signal for the same reason.


  1. Such a lovely summer day! It is still warm outside near the zoo, but I can feel the change. So be it.

  2. Yesterday was the second latest date on record to reach 76, and the third latest on record to reach 77. The only reason 75 is used is because it is a multiple of 5. Of course, 77 is a multiple of 7. And 11...

  3. Hi, this is a little off topic but with the recent warm weather it had me thinking ahead to my trip to Lake Chelan for the 4th.

    Does anyone know where you can find a current reading of the water temperature on Lake Chelan? I find it odd that after 'googling' for 20 minutes I can't find anything. I found buoy readings for both Lake Washington and Sammamish.

    Any help would be appreciated. Thanks!

  4. I have no idea but cold. Snow melt, no heatwaves, and that mass of water, don't see why it wouldn't be freezing.

    Never abide by it, but extended outlooks have reduced our previous above temp, below precip summer to normal normal and next winter as cold and wet. Stick a fork in this summer that will never start, I'm waxing up my skis.

  5. Why is 75 degrees "magical" or a "ceiling"?

  6. lake chelan is 55 degrees

    google "chelanpud.org"

  7. It was the best birthday gift a girl could ask for!


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