October 05, 2021

A Rapid Descent into a Cool, Wet, "La Nina" Fall

 This autumn has felt like we dropped off a weather precipice.

After a warm, dry mid-summer, September was unusually cool and wet, with impressive precipitation totals around the region.

And now, we appear to be stuck in a La Nina pattern, with an offshore ridge and cool, wet weather systems pushing southward over our region.

Folks who complained about the heat/dry this summer, have gotten their wish.  

Do you like temperatures rising in the 70s and 60s?   

 Forget it.  The latest European Center forecast for Seattle does not get us out of the 50s over the next 10 days.  One day doesn't get out of the 40s!.


The official Climate Prediction Center one-month precipitation forecast?  

Wetter than normal over our region (see below).   Three-month forecast?  Ditto.


Well-above-normal rainfall in September has resulted in many of our local rivers having normal or MUCH above normal water levels.  Plenty of water for returning salmon.

The extended precipitation forecast from the European Center through mid-November?  You guessed it.  Wetter than normal (see below).  Blue is much wetter than normal.


Why are we going to be stuck in this cool, wet situation?  

Because the large-scale upper air pattern has been stuck and will continue to be stuck, in a typical La Nina configuration, with a ridge of high pressure offshore and cool, wet northerly flow over the West Coast (see forecast below for Thursday evening for the pressures/heights around 18,000 ft).   


This configuration can be forced by the cooler-than-normal sea surface temperatures in the tropical Pacific associated with the developing La Nina.

 Water....the essential resource of our region...is back and our reservoirs, dams, and soils are being refilled.  And at least one group will be very happy:



15 comments:

  1. Replies
    1. Don't necessarily count on that, because we may get it.

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  2. Cliff, I thought the effects of la nina or el Nino don't happen until the first of the year and what does this current mean for winter?.

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    Replies
    1. La Nina can run for years straight through without a drop in to El Nino (mid 2007 - early 2009), for only mere months (1978) or, broken / separated by a few months (such as this year and last) and then reverting back in to La Nina.

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  3. Some folks say that your sense of humor is for the birds...but you really "quack" me up!

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  4. Will La Nina help the California severe drought?

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    Replies
    1. Unfortunately, no, even Cliff has said so as La Nina brings the jet stream our way, so California gets missed. Now, Northern California may be somewhat spared, but that's about it.

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  5. Well I am cautiously happy but I appreciate today's post. At the moment am so relieved that the fire danger has been minimized though outside burning is not allowed here until the 15th of this month.

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  6. (in my comment should have indicated location being southern Willamette Valley)

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  7. As a life long Northwetter and pluviophile, I love this forecast.

    Let it rain, rain, rain

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  8. Mass is an integral part of ones pac Nw winter weather enjoyment.

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  9. This is how the Puget Sound region should be, wet and cold, or cold and damp to seep deep into our bones that we sometimes feel chilly despite the heat being on. :-)

    As a native of these parts (born and raised in University Place, born at the old Madigan Hospital in the mid 60's, I approve of this message, LOL.

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  10. In spite of the recent precipitation here in Portland, the local MSM just keeps playing their greatest hits, 24/7. "Despite the record rainfall here in September and the recent rains in October, we're still in the grips of a multi - year drought!" They can all kick rocks.

    ReplyDelete
    Replies
    1. It takes a LOT more then one storm to get us fully out of drought territory. We need one medium storm each week for the rest of the year to even HOPE of catching up. If it were NOT for that one storm we would've been annually as dry as Redmond OR.

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