See below for title

“Hot ‘n’ pretty”

And it was yesterday.  But if I titled this blog page that, I would get people complaining that they weren’t looking for a cloud and weather report from the prior day.  Still, “hot and pretty” it was with those small Cumulus shadows drifting across our Catalina mountains, the shadows ever changing like the patterns in a kaleidoscope.  Can anyone tire of these views? I don’t see how.

SONY DSC SONY DSC SONY DSC

This last photo shows a “cloud street”, an intermittent line of small Cumulus clouds,generated by either the Tucson Mountains, or maybe even as far south as from Kitt Peak.  This line of clouds demonstrates that one of our best wind directions for rain is from the SW, as it was yesterday, and that was about the direction of movement for our those big rain cells on July 15-16th that drenched so much of the west slope of the Catalinas.  This direction brings air that is moving upward due to the increasing height of the terrain north and northeast of us, and storms are not compromised by downslope flow as they were the day before when the wind rushed out of the north.

Many of you will want to know if I saw any ice from these clouds yesterday, to compare with your own notes.  The answer is “no”, I did not see any.  The sounding below shows why.  Tops of the clouds were only about -5 C (23 F) and that’s too warm for ice to form in a cloud in Arizona–can happen over the oceans, or in clouds with real warm bases, but not here, not yesterday.  Yesterday’s cloud bases were up around 12,000 feet above sea level, highest tops about 15,000 feet, so the thickest clouds in these photos were maybe 3,000 feet thick (1 km).  See below.

Atmospheric sounding for Tucson from a balloon launched between 3:30 and 4 PM yesterday.
Atmospheric sounding for Tucson from a balloon launched between 3:30 and 4 PM yesterday.

 

July rain “factoid”:

Douglass, Arizona, has just passed the TEN inches mark for rain this month, a remarkable amount that is several inches over the prior record! Definitely have to get down there to see what TEN INCHES does to plant life there, maybe see some nice puddles, running streams, the whole great scenes of water in the desert.  I think you should, too; get out of the house, experience some summer life out there, stop watching so much TV…  :}

No rain likely here through the end of July.  Boo-hoo.

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.