March 20, 2011

Changing Weather Pattern Reduces Radiation Risk, Brings Improved Weather

The large-scale weather pattern has shifted in a way that is going to give Seattle far better weather than southern California and protect us from any Japanese radiation for a while.

What configuration can provide such a boon? Large-scale troughing on the West Coast that is going to send weather disturbances to our south.

Here are two upper-level weather maps for the 500 mb level (roughly 18,000 ft).

The airflow parallels the lines and the closer they are together the stronger the winds. A strong trough will be resident along the coast and the current of strong winds...often known as the jet stream...will be heading south into LA-LA land. Thus, while substantial rainfall will be falling over CA we will remaining generally on the dry side. In fact, this is currently a flash flood watch and wind advisory for LA! And with the flow moving south into CA any radiation-bearing particles crossing the Pacific will head south toward southern CA.

The Northwest has been sufficiently wet that even if we don't get a drop for the rest of the month, we will still have normal rainfall for March.


  1. Cliff, glad to hear a good weather report... I have a lot to do in my garden!

    Do you think this report is baloney, or is it something to be concerned about? I am so reluctant to believe ANY conspiracy theory.

  2. Summer yet someday come.

    It used to be that I could tell family and associates to come visit Seattle in August. Dry, Warm, Clear. The rule was 'never travel in August because that is when you want to be here'. For the last 3 years my grapes have not ripened and if feels like fall is well and truely here by the second week of that month.

    Do readings support this or was August always marginal?

  3. Cliff:

    This isn't particularly reassuring for your readers in Southern California like myself who have a pregnant wife at home.

    Could you please let us know if the rain should be avoided as the forecast calls for additional rain today and throughout the week...

    Concerned in CA

  4. Cliff, love your blog and your continued emphasis on the zero radiation risk we have during the latest panic/fascination locally. I would humbly suggest that you change the title of this post by omitting "reduces radiation risk." You can't reduce zero risk, so you are implying we do have a risk.

  5. Your report seem to suggest that there is radiation and that it is going only to CA, which contradicts your prior reports that there is no threat to the west coast. I just thought that it was written unprofessionally.

  6. The long range charts are showing an actual upper level RIDGE building over our area at the end of this month.It looks like we could finally get a few sunny days with 60+ degree temps! (Just hope that the models aren`t wrong.)

  7. OK, OK, so we're not all gonna die ;)- I trust you. However I did find it interesting that one of the UW physics profs, Hamish Robertson, started detecting minute amounts of radioactive particles on Friday - wasn't that after we had started shifting to a north wind? It would be interesting to see the meteorologists and nuclear physicists do a joint study:,0,6446696.story

    (Also, I think some may have been detected by UC Berkley)

  8. Cliff:

    Could you please comment on what levels of radiation exposure WOULD cause concern for pregnant women living on the West Coast? If even small amounts of secondhand smoke are troubling then surely even small amounts of radiation exposure could have health consequences for sensitive members of the population such as expecting mothers, correct?

  9. And so begins the months on end of sun and sun and, oh yea, more uncomfortable sun. It seems summer is starting a bit earlier than usual this year.

  10. "if we don't get a drop for the rest of the month, we will still have normal rainfall for March"

    Yes, it has been a very dreary month so far.

  11. CBS in Los Angeles has reported that monitors in Seattle have recorded small(tiny) amounts of radiation from Japan.

    The amounts recorded are far too low to be of any health concern, but how is this getting through the ridge if all the weather is going down to California?


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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