The lenticular that came for breakfast and stayed for dinner

Some of you already know that there is a favored position for a lenticular cloud downwind from the Santa Catalina Mountains.   Yesterday, a little fluff of Altocumulus lenticularis kept reappearing all day!  It didn’t have the “classic” look of a lenticularis early on, but that’s what it was, hovering over the same spot, changing size some, disappearing then reforming over the same spot.  That rough bottom early on suggests turbulence.  You don’t want to fly there.  Often, flying IN lenticular clouds is, as the smoothness suggests, completely lacking in turbulence.  Its when you come out the downwind end of those clouds that you can experience some nauseating bumps.

Why was the lenticular cloud there all day?

Because there is a standing wave, or hump in the airflow downstream of the mountain that raises a moist layer to its saturation level where a cloud must appear, and not much changed in wind direction and moisture all day up there.  The morning and evening sounding for Tucson were almost the same.  Also, while that lenticular cloud was nearly always there, it was often “buried”; obscured inside that sometimes thick layer of Altostratus with its virga that moved in during the afternoon hours.

Some photos. (BTW, since I started adding captions, WYSIWYG has gone bonkers in the Word Press edit page.  So excuse the strange organization and text in odd places–still learning here.)

1. Kind of a ragged Ac len, right side, 6:10 AM AST. Location, location, location tells you its a standing cloud, not one that will move off with the wind.
2. Zoomed in on it a bit here for a closer look a few minutes later. 6:14 AM AST
3. 6:19 AM AST: appears to be solidifying some.
4. Thought I'd eat breakfast, help entertain winter guests, then came out a few hours later, well two, and its still there! 8:13 AM AST.
5. It's 4:59 PM AST. A thinning of the Altostratus allows the lenticular to be seen more clearly again. Its 4:59 PM AST.
6. It's 6:29 PM AST and its STILL hanging around!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Below, photos of some of the other clouds of yesterday. I have to say if there was a disappointment, it was that there wasn’t as much Altocumulus as I thought, and virga trails were not as long as I expected, either.  They were barely hanging down from that Altostratus layer, an indicating of smallish snowflakes in the Altostratus layer as well as very dry air below it.

"Altostratus over horse arena".
Classic here of Altostratus translucidus (thin enough so that the sun's position can be determined) with a few scattered Altocumulus clouds below it. 5:12 PM AST.

 

 

 

 

 

 

 

 

 

 

 

 

Lastly, a sunset shot, indicating the back edge of these high and middle cloud layers was over the horizon to the west.

6:43 PM AST.