January 18, 2010

Its 9 PM and Its Getting Warmer Out!

Something very strange is going on right now (9 PM). It is getting warmer! I was just down in Kent and the temps felt nearly 60 (and there were modest winds from the east). As a drove through downtown Seattle it was 57F. Here is the temperature and wind trace (plus other goodies) at the UW. It has gotten warmer!
The sun is down..why is it getting warmer?

The east winds know!

The next major low system is moving up the coast right (see satellite image and forecast sea level pressure for 10 PM tonight).

Pressures are dropping (in fact they are really very low tonight...lower than last night). A fairly good pressure difference has developed across the Cascades and there is easterly flow at crest level. The result...easterly flow is moving through and down Stampede Gap (a weak area in the Cascades). Here is a model simulation of the winds at 10 PM. Some strong winds in the foothills and to the immediate west (sustained 20-35 mph, gust to 50 mph). One NWS spotter near Enumclaw clocked 80 mph.

There winds are influencing mainly the east side of the Sound from roughly Tacoma to north Seattle. (see graphic). Note how much colder it is northeast of Seattle (click on image to enlarge).

As the air sinks it is compressed by higher pressure and warms (see my book for more on this). So we are warming right now due to air compression.

I am a little tired now so I won't talk about all the exiting weather coming up with mega-deep lows passing off the S. Oregon coast bring storm-force winds there. Or the huge rainfall totals that will hit California and Arizona. That is why we have the NWS. Those folks are there three shifts a day, every day of the year. Their contributions are important and often unrecognized...but they are very good.


  1. 52 and windy here 3 miles NNE of Monroe, and it was showing as high as 57 degrees when I drove through Monroe a few minutes ago (also windy in town). My un-calibrated barometer reads 979 (I'm about 400' above sea level). Finally we get some wind!

  2. It's like a hurricane here in Enumclaw!

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  4. I am in Enumclaw too...we JUST got our power back on! My house is SHAKING from the wind gusts! Any idea of how strong those winds are? How long will they last? Will they get stronger?

  5. East Bellevue says... 57F, gusts to 25 with steady wind around 16 mph from the E-SE. Pressure is 985.2 and falling... calibrated measurement from 0.8 miles away at Phantom Lake Elementary!

    I'm glad this weather is happening a bit earlier tonight. I wanted to check it out, but I'm tired after being up til 4 am yesterday (and I still missed our biggest gust last night). :-(

  6. Thank you Cliff for giving some kudos to the NWS. They are an east target sometimes.

  7. The NWS folks are indeed very good, as Cliff says, but they don't understand our local weather the way Cliff does, and they don't explain it to laymen nearly as well as he does.

    So, Cliff, they're NO substitute for you.

  8. Sure it's getting warmer. It will be February soon and winter was over the second week of December. lol

    The real question is whether (or weather) we'll be having summer in Western WA this year.

  9. Oh indeed it is. 59 degrees in Olympia this afternoon. I wonder if this is a harbinger of previous winters where Dec was cold and snowy and then a false spring in Feb followed by snow in March?

  10. Enjoy your blog Cliff. I'm a mid 50ish Seattle native. The weather has always been of interested to me. It's really fun reading someone who explains what is happening and why! Not to mention what has a good likelihood of happening.

  11. . Boy do I love this warm spring weather. I was out pruning trees in my shirtsleeves today. Tonight I was checking the forecast for Santa Barbara, CA because of a trip I need to take there real soon. Wow.. the NWS 7 day forecast page leads of with:

    High Wind Warning
    Flash Flood Watch
    Coastal Flood Advisory
    High Surf Advisory
    Coastal Flood Watch
    Special Weather Statement
    Hazardous Weather Outlook
    Hydrologic Outlook

    Combine that with heavy snow in the Mt. Shasta area and I think I'll just wait it out here in paradise.

  12. How can the pressure be so low and no storm is occuring?


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