May 13, 2011

Coldest Spring Confirmed with Barbecue Index

Today we are getting a break from the cold (more on this later). But I thought it would be interesting to unearth the old "Barbecue Index"---the number of days we have hit 60F or more this spring (to be exact from March 21st to May 11) at Sea-Tac Airport. This is the kind of rigorous research one expects from the UW!

The answer: the index shows this is the WORST YEAR since record-keeping began at this location with only five days reaching 60F. Here is the plot (courtesy of Neal Johnson of the UW):

Even more irritating to many is the trend of the past 7 years---downward.

A big question is whether we are going into a cold (negative) phase of the Pacific Decadal Oscillation--a natural variation over the eastern Pacific basin (see PDO index below). We were in a cold phase during the fifties to the mid 70s, followed by a warm phase until the early 2000s. But what are we in now? A new cold phase?

Here is an amazing shows the difference (anomaly) between the temperature in the lower atmosphere (850 mb--roughly 5000 ft) and normal (climatology) considering the period from March 15th to May 11th. Very large cold "bulls eye" over the Northwest, while a warm center is found over Texas. Says it all. It also illustrates why you can't talk about global warming my looking at ONE location---we might be cold, while others are warmer than normal.

Many of you are asking about this summer. We are now in a rapidly weakening La Nina and our forecast models indicate a cool period later this weekend into early next week. No major warm ups in sight for next week. This summer we will be in a neutral pattern (neither La Nina nor El Nino) and in any case we have little if any skill for summer predictions. So I can't tell you and neither can anyone else.

But one we will get into the mid-60s and Saturday will be decent (low 60s with increasing clouds) and generally dry (few showers at most). But Saturday night we head back into serious rain and Sunday will be a and wet again. In any case, this is better than droughts and wildfires (Texas), tornadoes (Alabama), or flooding along the Mississippi. Or the extreme snow of the eastern U.S. last winter.

Lets face it, weather is rarely normal, particularly if you look across the entire continent. We need to learn how to better predict it (my field's job) and adapt to it (everyone's job). You don't live in mobile home parks in tornado country if you can help it, nor by a large river that periodically floods.


  1. This Pacific Decadal Oscillation thingy. I am glad someone has said it. Never knew it was a term. I do believe of the last 13 snowpacks, only 4 years have had below normal snowpacks. That means 9 of the 13 have had normal or above average snow. So I believe this Pacific Decadal is in a cold phase.

  2. So it is not just me. So glad to read it here.We can only hope we get a good summer to try and make up the lost sunshine.

  3. It would be interesting to know whether the bbq index has become "more variable" over time, with higher highs and lower lows, or with a change in autocorrelation... to get at the change in "extreme weather" patterns.

  4. And I think my kids have played outside in the Seattle Center Fountain or in water in our yard every one of those warm days. Having grown up in AL, I'm always in awe of them.

  5. Interesting stuff! The rain this weekend comes from the east/southeast, not the normal westerly direction. Seems like a complex pattern setting up. I fly out to Norfolk on Sunday, but it's suppose to rain there too. Just one more reason why I need to live in San Diego :) Thanks for the info and charts on the PDO. We sure live in a complex area for meterology.

  6. Ah, the Scripps folks would seem to suggest we are indeed returning to a cold phase. Very interesting!

  7. The weather might be cold and terrible, but when we do get a party clear day the sunsets have been incredible. Last night's sunset that I saw in Skagit County was the most beautiful sunset I have seen in quite a few months.

  8. Being a NW native I BBQ year-round, weather makes no difference to my BBQ index. The only deciding factor is if I have enough charcoal to get the temperature up to 350 degrees when it is 20 degrees and snowing sideways.
    But, I am wondering if the snowplowing business might be improving for the next 10 years.

  9. The seeming lack of severe weather (tornados and floods) is small conciliation considering the miserable, endless winter we're in. Sort of like Groundhog Day with grey skies.

  10. It is raining steadily, at 52 degrees, near sand Point. I checked the animated satellite on KING 5, and I see what may be an unsusual pattern. Not an atmospheric river,but clouds coming from California.

  11. "You don't live in mobile home parks in tornado country if you can help it, nor by a large river that periodically floods." Ah, but Cliff, we live in earthquake country.
    Keep up the wonderful work.

  12. Washington state has the blue dot and Texas has the red - it would seem that politics may be a useful tool in predicting the weather.

    Kidding aside, that red dot in Texas also corresponds to 50% of the state being in a D4 Exceptional Drought.

    As for the Pacific Decadal Osciliation thingy, with climate change, the past phases no longer apply - expect amplification of all weather cycles in the future.

  13. How usual is it to have this kind of really heavy rain? In May?

    One good thing; in the PNW one can really enjoy a 60 degree day (without rain, even without sun!) and experience a kind of Nirvana that is rare for folks elsewhere. We do live in a beautiful place and I TRY to remember that. Thanks, Cliff, for all you do!


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