The First Frontal System of the Autumn

 It is not too soon to think of Autumn, and the atmosphere is about to remind us of the wet future ahead with the first frontal system of the upcoming wet season coming in next week.

Sometime during the second to third week of August, the first fall-like system approaches, bringing some showers and cooler weather, followed by warm summer weather.   This year will be no exception.

The climological probability of getting .01 inches of rain at Seattle is shown below.  Around July 28, we hit bottom, with less than a 10 % chance of such rain in a day.  But by mid-August, the probability has doubled to 20%, reaching 30% a week later. 

The latest ensemble of many forecasts by the National Weather Service GFS model shows many of the runs producing rain sometime on August 6-7:

The UW high-resolution WRF model shows a nice wetting over western Washington and southern BC on Thursday over the 24-h ending 5 PM that day.

There will be a nice frontal trough of low pressure and a good wind shift......tame by winter standards but respectable this time of the year (see surface map below 5 AM Thursday).  The red line shows the frontal position.

The simulated cloud field that morning will make one think of our cloudy future:

A good aspect of this upcoming system is that it should restrain the fires currently burning in the Olympics.

And for one day, you will be able to put away your sunglasses.  Enjoy.

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Theater Review

Like Shakespeare?  I just saw an excellent performance of Richard III at Magnuson Park by the Greenstage group.   Really recommend it.   These will do it again at 7 PM Sunday at the same venue (and other dates/times as well).  Free (but you can give contributions).