Rain 2 for November 2013: 0.23 inches, lightning and a couple of grape-sized hail stones

We have a monthly rain total that’s not zero! But will there be more this month?  Stay tuned until November 30th!  (Nothing imminent.) In the meantime, a very pretty blue sky day today pocked with residual Cumulus clouds, maybe some virga. There’ll be nice cloud shadows and sun on the Catalinas again today.

In the meantime, here are the Pima Country reports for last evening’s rain.  The heaviest amount seems to be at our end of the Catalinas at Pig Spring, with 0.39 inches.  Nice.

Yesterday’s clouds and why

Not exactly the way they were supposed to go, the ice cloud shield WAS on the horizon to the NW at mid-day but didn’t advance over us, but rather fizzled out.  That’s OK.  What was left of it enhanced a spectacular sunset through the rain.

The Cumulus clouds were the stars of yesterday, doing something in the way that the old rock band, Jethro Tull used to do.  The members of JT would come out on stage as roadies, fiddle around with equipment for awhile, then suddenly turn around and began playing!  Oh, who can forget Jethro Tull and that Aqualung album that roiled the rock waters back in 1971 by interrupting heavy, driving rock with acoustic interludes and flute playing (!!! )? What were they thinking?

Well, our Cumulus clouds pulled a fast one, too,  after hanging around, fiddling around not doing much, then blammo, here comes the ice around 4:30 PM, followed by an eruption into an honest-to-goodness Cumulonimbus cloud with a strong rain shaft, sending forks of lightning to the ground, and pea to grape-sized hail bouncing off the roof with winds gusting to over 30 mph. This spectacular happenstance was triggered by a surge of much cooler air in conjunction with the lifting of air associated with our approaching trough just above those Cumulus tops yesterday afternoon.  That steepened the lapse rate;  spring-loading those Cumulus clouds as it were, allowing tops to rise and still be that bit warmer than the surrounding air and stay buoyant as they rose. Here are a couple of TUS balloon soundings rendered by the Cowboys of the U of WY:ann 2013110412.72274.skewt

ann 2013110500.72274.skewt

While cloud fattening and ice was expected late in the day with sprinkles and light showers, the U of AZ mod run based on 5 AM AST data was spectacular yesterday morning in foretelling this larger eruption as that cold air moved over us.   But were grape-sized hail stones and LIGHTNING expected?  Not only “no”, but “HELL no”.

Here’s your day, reprised below, of which the MOST IMPORTANT part was the first detection of ice, very tough yesterday, but a precursor to the rain that began to fall a few minutes later.  You can also reprise your day here thanks to the U of A time lapse films.  Watch what happens around 5 PM, if you can read the tiny font in the lower left hand corner.

Here is the pictorial of your cloud day below:

12:06 PM.  Flatness.
12:06 PM. Flatness.
3:49 PM.  Clouds fattening, no ice visible anywhere yet.  Nice cloud street generated upwind of Pusch Ridge, floating over Catalina.  Shows wind direction at cloud level is from that direction.
3:49 PM. Clouds fattening, no ice visible anywhere yet. Nice cloud street generated upwind of Pusch Ridge, floating over Catalina. Shows wind direction at cloud level is from that direction.
4:01 PM.  Nice cloud shadows and sun moving along the Cat Mountains, too.
4:01 PM. Nice cloud shadows and sun highlights moving along the Cat Mountains, too.
4:34 PM.  Something's definitely happening now.  Note turret protruding on the left.  Clouds evolving into larger masses to the south, the cloud street having broken up.  And, these are clouds that
4:34 PM. Something’s definitely happening now. Note turret protruding on the left. Clouds evolving into larger masses to the south, the cloud street having broken up. And, those massing clouds are upwind of us.  Still, no ice evident.
4:35 PM.  Ice! I can't believe it.  Its going to rain!  Can you find it?  This is REALLY tough.
4:35 PM. Ice! I can’t believe it. Its going to rain! Can you find it? This is REALLY tough.
4:37 PM.

4:37 PM. Close up of ice. A higher top was breaking off to the NE and was converting to ice.

 

5:07 PM.  By this time, ice had formed in cloud clusters all around Catalina, and this beauty erupted upwind.
5:07 PM. By this time, ice had formed in cloud clusters all around Catalina, and this beauty erupted upwind.
5:22 PM.  About to strike with hail, lightning, wind and rain.
5:22 PM. About to strike with hail, lightning, wind and rain.
5:35 PM.  While the rain and hail weren't done yet, it gave this sunset pictorial.
5:35 PM. While the rain and hail weren’t done yet, it gave this colorful scene reminiscent of summer sunset color except that the sun would be setting WAY over there on the right out of view.
5:40 PM.  Second thunderstorm with hail in formation upwind of Catalina.
5:40 PM. Second thunderstorm with hail in formation upwind of Catalina.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.