TSTMS overnight and this morning drop 0.11 inches

Well, it could have been more I suppose; some areas of central and northern Arizona have gotten between a half an inch and an inch of rain overnight.  Nevertheless,  it was great that a passing thunderstorms (“TSTMS” in weather texting) happened here in Sutherland Heights overnight, fabulous, really.    Dropped 0.28 inches on Mt. Lemmon, btw.

More scattered showers, and maybe a thunderstorm or two, should develop today.  Keep cameras well-oiled  for some great cloud scenes.

Yesterday’s clouds

8:04 AM. In the beginning….. Unlike the day before, our shower clouds didn’t move in, but rather had to start from something akin to poppy seeds.   Still water highlights on Samaniego Ridge.
12:06 PM. Cumulus increase in size and number. No ice yet.
2:14 PM. First minute amount of ice begins to show up underneath downstream cloud portions. You’ll have to be awfully good to find it!
3:37 PM. Ice, and now well-developed virga, is plentiful in many of these shallow clouds.
4:00 PM. Numerous light rainshowers and glaciating shallow Cumulus clouds dot the horizon to the SW,
6:58 PM.  Shows the fine structure of virga, trails that can be only 5-20 feet wide as they drop out of a cloud.  Seems like a nice scene, too.
6:58 PM. Shows the fine structure of virga, trails that can be only 5-20 meters wide as they drop out of a cloud.  Strands like this are usually soft hail, or what we call “graupel.”   Snow virga like this tells you that cloud bases are well below freezing, and on a warm day are very high above the ground.  Yesterday’s late afternoon cloud bases were up around 14 thousand feet above sea level, at about -5 C (23 F).   The virga melted into raindrops behind the cloud below it.


7:04 PM.  A light rainshower advances on Catalina.
7:04 PM. A light rainshower advances on Catalina.  Where the pinkness disappears below the main cloud base is where the snow  virga is melting into less visible raindrops.
7:06 PM. Another fiery sunset highlight involving a Cumulonimbus cloud. Cloud tops were beginning to deepen noticeably by this time.

The End

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.