November 23, 2017

Temperature Records On Wednesday. Why?

Yesterday was a very warm day across the region, with many locations 15-20F above normal and several stations achieving daily records. 

Here are the highs on Wednesday.  The lowlands of western Oregon and Washington were in the low to mid 60sF, with some favored locations (south of Tacoma) hitting 70F. 

Some daily records were broken.  Here is a nice graphic produced by the Seattle NWS Office, showing the high temps, with the stars indicating daily records.

The reason for this warmth was that we had the perfect set up for a strong atmospheric river event, with warm/moist tropical air moving northward.  The map below shows the upper level flow at 500 hPa (about 18,000 ft) at 4 PM Wednesday.  Big ridge of high pressure over the southwest U.S. and a strong trough over the eastern Pacific.  The perfect configuration to produce a narrow current of warm, moist from the southwest that hits the NW. 

 To see what is unusual about this pattern, here are the anomalies--the differences of the heights (or pressures) at that level from normal.  Unusual ridge centered on Utah, with anomalous low pressure to the east and west.

The following figures shows the climatology of  4 PM surface temperature at Quillayte, on the WA coast, based on over a half-century of data.  The red lines show the daily maximum and the circle shows yesterday's observation.  You will note that we were near the daily maximum, but there were several days in November with similar (or even higher temperatures).   This pattern has happened before.

Now, Seattle's wacky local alternative newspaper (the Stranger) is making claims that this is proof of global warming (see below), but that claim has little basis in truth.

One can only make a case for global warming based on trends over an extended period, not one extreme event.  So why don't we look at the long-term (1900-2016) trend of average November maximum temperature over the Puget Sound lowlands for a period of more than a century (this is from the NOAA/NWS climate division data)?    Not much trend there!

And this lack of trend makes perfect sense because the surface eastern Pacific Ocean is warming up more slowly than almost any place on the planet.   And there is no research to suggest that the anomaly patterns shown above will become more frequent under global warming....this is an areas of research that I am working on.

The air above us is rapidly cooling and the Aloha breezes will fade.  Something to contemplate while you eat your turkey today.


  1. The high-temperature trend chart you post is misleading. You imply there's little evidence of warming due to climate change in the Northwest. However, a 2014 study found that temperatures have risen 1.3 degrees F since 1901:

  2. Unknown.... not misleading at all. I am showing real data for ONE MONTH for ONE REGION. The study you noted was not limited to November or a specific area. An overall annual rise for the entire area (including the eastern side of the region) of 1F over the past century is not unreasonable. But is quite small..cliff

  3. The Stranger - excellent bird cage liner, but not useful for anything else.

    1. John K. So true! Your comment just made my day.. We have to be very careful where we get our info. these days. I think I will trust Cliff on this one.

  4. Record temps made for a great day raking up leaves in the Skagit Valley. Somehow we escaped with no rain. No wonder "Blue Skies" by Willie Nelson is one of Bill and Melinda Gates favorite songs:

  5. I see that a UW study shows a 0.8 F increase in maximum temperatures during 1895-2014, but a 1.8 F increase in minimums. Connected with that, it also shows a 30 day increase in frost-free days.

  6. Cliff, looking at the (well done) NOAA database that you cite to show little change in Nov. max I have noticed a significant increase ( .3degree/decade) in Minimum temperatures in the summer months. I think you have mentioned this before but could you comment on the cause of this trend.

  7. Yes, it's happened before. November 30, 1999, the day of the WTO protest and Seattle police riot. What started as a raining morning, by 10:00 am had produced rainbows over downtown Seattle, followed by a day of t-shirt (for those not in costume) near summer weather. The trade folks had hoped that end of November weather would dampen demonstrations. An "anomalous" weather pattern saved the day.

  8. @DEORTMAN - The high temperature on 11/30/99 was 50 degrees.

  9. i think mudede is just trolling you. or hes crazy.

  10. O.K. still only nine degrees below the record high for the date.


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

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