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....