What a Change A Week Makes

A week ago, there was no snow on the mountains and major smoke from wildfires on the eastern slopes of the Cascades.

Monday morning, lots of snow in the mountains and no apparent smoke.

A week ago, several surface monitors indicated poor quality with very bad air near Wenatchee.

Monday morning, nearly all sensors showed good air quality (green).

A week ago, the Snoqualmie River (near Carnation) was at record low levels for the date.  This is no longer true, and soon the river will rise to ABOVE normal levels.

Temperatures that were consistently rising above average highs are now consistently below normal highs, as illustrated by a plot of high and low temperatures at SeaTac airport.

A major weather shift since last week.  

And after a few dry days, expect rain to return Friday and  into the weekend (see total through Monday morning below).   

Moderate to heavy rain on the western sides of regional mountains and a nice rainshadow from Seattle northward over the lowlands.  Enjoy.

The Snow Season Begins

 The image from the Crystal Mountain cam this afternoon said it all:  substantial snow had fallen over and to the east of the Cascade crest yesterday and this morning.

Another way to appreciate the change is to look at the snow water equivalent (water content of the snowpack) over the past two days.   At 11 PM Saturday, there was essentially no snow over western Washington State, except for the tops of major volcanic peaks

By 11 PM Sunday night, light now covered the higher elevation of the Cascades and Olympics, as well as the eastern slopes of the Cascades.

So much snow fell on Blewett Pass (at 4000 ft), south of Leavenworth, that they had to close the road (US 97) for a while!

The fact that cold easterly winds (from the east) were forced to rise on the eastern side of the Cascades, producing clouds and precipitation on that side, was made obvious by the visible satellite image this morning (below).  For a change, western Washington was in the lee rain shadow!

Temperatures have substantially dropped over the mountains during the past several days.  

Over the past week, temperatures at Stampede Pass (in the central Cascades) rose to around 60°F on October 7-8.   This morning it was around freezing!

At Camp Muir, located around 10,000 ft,  the temperatures this morning were in the teens:

If you want to enjoy outdoor activity, I would suggest you do it during the next few days.  

The weather will go downhill on Friday and over the weekend.