August 22, 2013

Coastal Complaints

There have been a steady stream of complaints by those living or vacationing on the Washington and Oregon coasts.  While the interior of western Oregon and Washington have had what probably has been the finest summer weather in two generations, those coastal folks claim they have had a cloudy, mediocre summer.   Are they whimpering weather wussies?   Or is there some truth to their protestations?  This blog will reveal the truth.

Well, first let's document the warmth and sun of the interior.  Here are temperatures at Seattle-Tacoma Airport for the past 12 weeks, with the average highs and lows noted for reference.  Over half the days have had maximum temperatures above normal, with only a handful below normal.  Only one day got to 90F.  Heaven.
Head east of the mountains, pretty much the same story.  Here is the record at Pasco...most days have gotten above normal, with the exception being those thunderstorm days in late June.
But what about the coast?  Here is the situation at Hoquiam.   There was a long stretch of days below normal in late July and the first half of August, with some recent warming.
Perhaps a better way to see the story is the difference between the average maximum temperature from normal for the last two months.   The coast is cooler than normal (green colors), while the rest of the state is warmer than average.    So perhaps the coastal complainers have been on to something.
What about precipitation over the past two months?   As shown here, the mid-coast was a bit wetter than normal, the mountains were dry, and the eastern slopes of the Cascades and much of eastern Washington were wetter than normal due to the bountiful thunderstorms.
 This HAS been a very unusual summer.   Very little offshore flow, avoidance of 90s, almost no onshore pushes of marine air into the lowlands.   Haven't seen much evidence of the thermal trough of California pushing northward into our region.  WHY?

Much of the summer we have been stuck in the same boring pattern with high pressure offshore.  Like this.  Such patterns push cool, marine into the coastal zone, but are not strong enough to 

maintain low clouds all day in the inland areas, which get some morning clouds that burn off early for pleasant temps.   Lots of days with satellite pictures looking like this--lots of low clouds offshore and on the coast.

We have also had a number of days with weak troughs offshore...enough to keep clouds in there and to promote thunderstorms over eastern Washington.  But not strong enough to spread steady rain over the interior.

The pattern is now about to change, with the development of a stronger, persistent trough off our coast (see map for Friday at 5 PM).   Showers along the coast, thunderstorms east of the Cascade crest, and lots of clouds for the rest of us.  It couldn't last forever....


  1. Having lived in the PNW for over 50 years, this summer has been about the best I can ever remember. Well, weather wise anyway (how do you beat a sunny summer as a kid with all that time off). Temps have been a bit warm for my tastes, but low to mid-eighties is definitely not hot and miserable. Every night has cooled pretty quickly and the morning warm-up usually has it hitting about 70F around noon. Almost no rain all summer.

    Nope, it just doesn't get better than this one. We have been 3-5 degrees cooler here in Fauntleroy than at the airport so even that 90 degree day was a max of 87 here. Those 4 or so days were the only days all summer that we ran the portable air conditioner and that was mostly just due to the humidity hanging around at that point. Since then it has been typically below 70F every evening by 8 or 9p and opening up the house has been all that was needed.

    A perfect summer indeed.

  2. Spring and early summer (most of June and first week of July) on the North Oregon coast was incredibly beautiful. We had lots of sunshine and warmish days.Since then it has been quite overcast and cool (and even some moderate rain a couple of days last week)with a few beautiful days in between. I suppose not too much out of the ordinary- just have to welcome what comes. Here's to a great September!

  3. My sense is that at 2pm today, 8/31/13, the sun was hotter than it would have been several weeks ago at the same time of day
    My reaction may of course be psychological.
    Could it be that at this time of year, there is less moisture in the air to filter sun's rays?
    Could it be that the angle of the sun these days creates a lens effect?
    Could it be that the more of my body is exposed to the lower sun's rays?
    None of the above?
    Bob Dunshee


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