Stormy, pretty weather

It’s great when things are as they are supposed to be.  Below, “the usual” kinds of scenes in July in southeast AZ from yesterday, such as Cumulus boiling off Mt Lemmon in the late morning, followed by dense rainshafts in almost every direction in the later afternoon.  I love these scenes!

Well, “usual” for SE AZ, except that high reaches of the Canyon del Oro wash watershed were deluged by 2-3 inches of rain (see two of those dumps in progress in the second and third photos below).   And Mt. Sara Lemmon had over 2 inches! (Must check washes out this morning to see if any are running around Catalina and environs, and how green it is already starting to get.

Here in Catalina land, after another 0.27 inches yesterday and overnight, we now have had 2.37 inches since the beginning of July!

The very pleasant news ahead is that the numerical forecast model by our friends in Canada, that can be seen here, is now suggesting, based on last evening’s data, that a series of itty bitty disturbances1 in the upper air are going to affect our region from now through July 13th.  These little lows/troughs arise from the tropics and their role is to take the underlying humid air and organize it into larger clusters of thunderheads (aka, “Cumulonimbus capillatus incus” clouds;  use this name if you want to impress your friends) so that the rains last longer, and might be heavier than on days with no disturbances aloft.  How cool is this forecast except for those times when the roads are impassable?

I have not yet checked other model outputs, ones that might be different, because I like this Canadian one the best already and don’t want to know other things that might ruin my current very good mood.  Ignorance truly IS bliss!  However, I do feel that the “pendulum” has swung back to the wet side here, as it always eventually does in climate, and so there is that pinch of intuition thrown in that wet forecasts are more likely to be correct.  Lets hope so.

Finally, even ordinary gray skies are pretty, even dramatic and interesting in weather like this.  Check out the last photo, taken in the evening after the first rains in Catalina.

The End.

1 In the perhaps unneeded technical jargon of atmospheric sciences, they might be described as “mesoscale”–namely, ones much smaller than the gigantic highs and lows we see on the usual weather maps for the whole US











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.