Stunning Lenticular Clouds Downstream of Mount Rainier

Native Americans, who were astute observers of the natural environment, had a saying:  "when Tahoma (Mount Rainier) has a hat, rain will soon follow."

Today it developed a hat of great beauty.

Looking out the window of my colleague, Qiang Fu, this afternoon, I saw it.  A series of stacked lenticular (lens-shaped) clouds downstream (west) of Mount Rainier (see below).  Stunning.


A bit closer view by Nicole Geer (below) shows the structure a bit better.


But why not go far closer....say from the nearby peak of Crystal Mountain, the home of a wonderful 360° high resolution live cam?

The view around 4 PM was extraordinary, with the "stacked plates" of several lenticular/mountain wave clouds clearly evident.


Pull back and you can get some perspective.  Stunning


And as the sun set and dusk settled in, the lenticular clouds remained, even as the general sky cleared a bit.  

As discussed before in this blog, lenticular clouds form as air is forced to rise by a mountain barrier, and then, like a swing, oscillates back and forth in the vertical (see figure below from my weather book).  As the air rises, it cools, and if moist enough, a lens-shaped cloud forms--with the potential to get several stacked clouds depending on the moisture structure in the vertical.  The clouds evaporate as the oscillating air sinks.

Having air close to saturation is good for the development of lenticular clouds, as is increasing wind approaching the mountain.  Both occur as weather systems approach the area--thus, there is good physical reasons for the Native American observation about a "hat" forming on the big mountain before rain falls.  In fact, the 1:30 PM infrared satellite image Friday (see below) DOES shows a weather system offshore--one that is heading towards our region.

Bottom line:  If you don't have a weather satellite handy, you can learn a great deal about future weather by being a perceptive observer.



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