Another big day; scattered amounts around us of more than THREE inches again; we only got 0.18 inches!


Trying to be excited for those around us who got all that rain yesterday while we received a paltry 0.18 inches here in the upper reaches of Catalina.  Still it was another good little rain for our local desert.

The 24 h rolling archive from Pima County rainfall gages is here.  Most seen here?  2.01 inches at Finger Rock and Skyline, Tucson.  You’ll see that storm in the movies.

Also, check the more comprehensive U of AZ rainfall network here.  In fact, you might as well join up, too.  It would get you out of your rut.  Think how exciting it would be to go out in the morning and see how much rain fell in your gage in the previous 24 hours!  Maybe someday you might win the “rain lottery” and have the biggest amount anywhere in the State!  The most reported so far this morning is a deluge of 3.17 inches over by Picture Rocks again.  Good grief, have they been getting hammered.

What a July this is turning out to be!

Here we are in Catalina, its late afternoon, it has just rained again, the temperature is a chilly 70 F, dewpoint 68 F (almost saturated), with Stratus fractus just above eyeball level lining the hillsides!  Its an amazing scene for an afternoon in Catalina and vicinity in July.  And so DARK!  Here is that odd scene from yesterday afternoon:

4:42 PM Stratus fractus is that low bar of clouds in the foreground just behind the tree.  Makes you want to run over there and play hide and seek in it.

Relive yesterday, as though you were in the city of Tucson shopping possibly, here in this movie, courtesy of the U of AZ Weather Department.  The movie is rated “R”, for violence since the sky goes WILD in the afternoon, winds going every which way.

Also, in this time lapse you will get a sense of how rapidly moist air is flowing across us from the east to east-southeast.  This movie, comprised of  still shots taken every 10 s shows movement, like the day before, that is phenomenal for summer, more like a winter scene when winds are normally strong.  There are even Altocumulus lenticular clouds (almond shaped ones) hovering over and just downwind of the Cat Mountains!  Amazing.

But check the CHAOS in the mid and later afternoon.  Unbelievable.  Areas toward the Catalina foothills, during this chaos, got another 1-2 inches again yesterday.

In contrast, let us now look at the very same day in a time lapse film in Seattle, Washington, where Mr. Cloud-Maven person spent 32 years, most with the U of Washington Huskies Weather Department.  Here it is.  I sum up the totality of that movie for July 29th below:

Bor-ring!

Those Seattle skies, for the most part, were like eating plain, cooked oatmeal everyday, all day.

Below, the start of our exciting day, the middle, and the end has already been shown above.  Lots of nice rain shafts SUDDENLY collapsing down out of clouds.   A sequence of the big northwest Tucson storm early in the afternoon that moved off toward Marana is included as part of the middle.  That shaft really fell out fast, and how you could detect the icey tops BEFORE the shaft appeared.  I try to point out how you might have been able to do that in this sequence, and thus, and quite importantly, impress your friends and gain status and some kind of weather sage.

Today?

Just looked at the latest AZ mod output, as you can here (forgot to past link until now, 8:08 AM).  Colored splotches are where it is supposed to have rained that HOUR.  That model has a much less active day today, but much more active tomorrow.  Cumulonimbus clouds in sight today?  Oh, yeah!  But, none are SUPPOSED to get us today.  But these mods are always slightly inaccurate, so keep watching this afternoon.  Should be another photogenic day, if nothing else.

10:03 AM. What a pretty start!
1:29 PM. Cumulus congestus converts into a Cumulonimbus calvus. While no rain is falling out the bottom, check the top peaking through above in the next shot.
Also at 1:29 PM. Annotated. Icey tops barely visible, but reveal that this cloud is LOADED with precip, certainly would have a radar echo aloft now. In a perfect world, the flash flood warnings would go out NOW, even though it hasn’t gone out the bottom yet.

 

1:32 PM. The first fibers of rain are just starting to be visible at cloud base as the updraft collapses, too much weight up there in rain, hail, and snow.
1:36 PM. There it comes! Close up of the main dump.
1:48 PM. What was interesting was how huge this got in just a few minutes, how the initial outflow winds kicked off other cells around the first dump shown above.

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.