Strange Radar Circles Appear at Sunrise in Eastern Washington: Why?

Yesterday morning, near sunrise, a strange circular feature suddenly appeared in the weather radar over eastern Washington between Kennewick and Moses Lake (see below).  A band of precipitation was to the east.

A sequence of radar images shows the rapid development of this feature between 6:30 AM and 6:42 AM and it was gone by 7:27 AM.

So what is going on here?  An alien presence?  The meteorological version of crop circles?

As Sherlock Holmes would say:  "The game's afoot!"

First, piece of information.  Sunrise yesterday morning at Moses Lake was at 6:36 AM.

The second piece of information is that skies were clear immediately over the circle (see visible satellite image at 7 AM with a star over the location).

Nearby cams confirm the lack of clouds:

Invisible aliens that appear near sunrise?

Ready for the big reveal?   

It was birds and the feature is called a roost ring.

Birds are social creatures and often spend the night together to rest in huge groups, sometimes numbering in the thousands.  The resting spots usually have bodies of water.    

The center of the ring yesterday morning is shown by the red arrow below....a nature area with lots of lakes.

A picture from the ground is shown below.  Nice location for birds.

In the morning, at sunrise, the birds fly off in many directions, producing a circle in the weather radar, which essentially picks up the reflected signal from the birds at one elevation.

In my next blog, I will take on related topics:

Darkness Descends On Washington State

One of the lesser pleasures of living in Washington State is the "return of darkness" during the autumn.   The rapid decline in solar radiation is particularly noticeable this time of year.

And it is not a little depressing for some.

Seattle at 7:45 AM Monday morning.

To illustrate, below is the solar radiation received at the surface at a Seattle location near the University of Washington (the WSU Ag Weather site) from late June until yesterday.  

You can see the steady decline over time of the sun's rays and the recent plummeting as clouds increasingly intercept the declining radiation due to the normal seasonal changes in meteorology.

Yesterday we dropped to about a quarter of the radiation of the peak in summer.  Yuk.

Richland, with fewer clouds, shows a lesser decline, but it is still significant.

To better appreciate why September is the most depressing month for sun lovers, consider a plot of the average incident solar radiation in Seattle (below).   The vertical red line shows today.   

Wow.  The sun's rays reaching the surface are RAPIDLY declining.... roughly half of the peak in late June/early July.

The situation in Richland, with fewer clouds and slightly farther south, is a bit better.

The key drivers in our loss of the warming rays of the sun include the changing sun angle (the sun is lower in the sky) and the rapid shortening of the day.

The graph below shows you the length of day (light blue) and night (black) in Seattle, with the vertical white line today.   We hardly have much night in late June, but it is RAPIDLY increasing right now.

Just depressing.

The extreme seasonal variation in solar radiation in our region....both astronomical and meteorological...  has a lot of implications for solar energy and a reason why solar energy is really not a viable source in our region for much of the year. 

Let me illustrate with some official NREL solar energy graphics.  

For July, there is plenty of solar resource for the Northwest, particularly for Oregon and easterly Washington.  

September is still a viable month for solar radiation over the Columbia Basin and eastern Oregon, but things are rapidly going downhill in western Washington.  

 

By December only the southwest US and perhaps the southeast US are viable for significant solar production.

So if you are living in Washington State, time to think about the purchase of a sun lamp, and if you have the cash, a trip to a sunnier location during mid-winter.   No wonder Alaska Airlines purchased Hawaiian Airlines.