What we’re looking for

Clouds began building early yesterday on the Cat Mountains.  Bases initially below Sam Ridge.  It was a good sign of a possible “big day” since the lower the cloud bases initially, the more water the clouds will hold compared to a day with bases above Mt. Lemmon.

So, in our CMJ “club”, we look for that moment when clouds to begin form ice above Ms. Mt. Lemmon and her environs as the turrets climb ever higher in the morning and early afternoon sun, log it in our cloud diaries, and maybe compare to other recent days.

9:20 AM. Great portent for great rains. Clouds lining Sam (Samaniego) Ridge!
9:20 AM. Great portent for great rains. Clouds lining Sam (Samaniego) Ridge!
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10:32 AM. Cumulus beginning shooting upward, but tops are far below ice-forming level (around 20 kft above sea level on days like this).

 

12"24 PM. Turret tops now have ascended to about 20 kft or so.
12″24 PM. Turret tops now have ascended to about 20 kft or so.
12:28 PM. Same turret a few minutes later. Ice showing as droplets evaporate.
12:28 PM. Same turret a few minutes later. Ice showing (frizzy stuff directly above second car on the road) as droplets evaporate.  Unfortunately, those snowflakes, to melt into rain on the way down, have been orphaned from the updraft and are going to fall out into dry air instead of into cloudy air.  Few will make it to the ground.  That turret to the right has ascended even higher, therefore would be forming ice at this point, and rain to fall shortly.   (From the “Not taken while driving collection, BTW).  Traffic authorities remind drivers not to take a lot photos while driving.)
1:25 PM. An example of the rain that fell from those higher turrets. But again, the top sheared off so that a lot of the rain fell into drier air instead of down through the root of the cloud, and so showers were pretty light.
1:25 PM. An example of the rain that fell from those higher turrets. But again, the top sheared off so that a lot of the rain fell into drier air instead of down through the root of the cloud, and so showers were pretty light.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

While CMP was expecting a gigantic blow up any time after this, it only happened in one spot, a sign that the atmosphere was in a suppression mode, that is, was not helping to cluster updrafts below cloud bases yesterday. Those forces can trump great low level humidity, dammitall.

Here’s the ONE behemoth of the many that were expected, based on an eyeball assessment early yesterday:

3:46 PM. Gargantuan Cumulonimbus capillatus incus (has anvil) southwest of Marana Twin Peaks area. Estimate 2 inches in the core fall of rain. Overshooting top, barely visible here in the middle of the anvil, indicates extra strong updrafts.
3:46 PM. Gargantuan Cumulonimbus capillatus incus (has anvil) southwest of Marana Twin Peaks area. Instruction: Estimate 2 inches in the core fall of rain. Overshooting top, barely visible here in the middle of the anvil, indicates extra strong updrafts.
7:22 PM. Nice coloration on the Cat Mountains as a cluster of disorganized Cu hover over it, dead anvil behind it.
7:22 PM. Nice coloration on the Cat Mountains as a cluster of disorganized Cu hover over it, dead anvil over and behind it.

The weather ahead, immediately ahead

Lots of water in the air again today, and since yesterday was a “down day”, caused by some upper level negative feature passing by (often happens AFTER a good day, like the night before last), expect an “up day” today, more showers and thunderstorms. Now, lets see if the U of AZ model says that as well, for support of this SOP (Seat of Pants) forecast…. Yep!  Pretty happy right now. Go here to see the U of AZ Beowulf Cluster output for today.

 

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.