Tuesday, September 16, 2014

Smoke Front Hits Washington State

Something happened on Monday.   Sunday was warm and clear.  The mountains appeared close and sharply defined.

Monday was just as warm, but the visibility declined greatly with Mount Rainier invisible from Seattle.  The pictures below, taken by the Puget Sound Clean Air Agency at 3 PM Sunday and 3 PM Monday, shows the degradation.

Sunday, 3PM
Monday, 3_M

The reason for this loss of visibility?  

The northward movement of smoke from large fires to the south of Washington.  The USDA Forest Service maps shows the  big fires over Oregon and California (red and blue dots are the largest fires)


A plot of the winds at Seattle Tacoma Airport with height from 10 AM Sunday (right side) to 10 AM Monday (left side) illustrates the switch of winds from offshore (southeasterly) to stronger winds from the south/southwest.  (the y axis is pressure, with 850 hPa being about 5500 ft and 700 about 10,000 ft.  The red lines are temperature)

A visible satellite image over NW Washington on Monday afternoon (from the MODIS imagery) clearly shows smoke moving northward.


Smoke can produce wonderful sunsets and those watching Monday's sunset were not disappointed.  Here are a few examples.  The first by 76johnyb and the second from Skunk Bay Weather looking north from Hansville, Kitsap Peninsula.



When the smoke reached Puget Sound, there was a clear degradation in air quality, as shown by this plot at Seattle's Beacon Hill.


Finally, maximum temperatures on Monday were roughly 15F above normal for many stations, with some locations even reaching 90F and above!

Don't believe it?  Here are the max temps around western WA.  Cooler on Tuesday....













1 comment:

SkunkBayWeather said...

I flew home from Denver yesterday and the whole way up we saw the smoky haze. I was sitting next to a guy that does the trip every two weeks and he had never seen smoke like this. It was visible all the way from Denver, but it seemed especially bad as we landed at SeaTac....