“Feint” rainbow

For a few minutes yesterday afternoon, it looked like some unexpected rain was trucking over the Cat Mountains from the east-northeast late yesterday afternoon.  No one could blame you for getting your hopes up and misleading your neighborhood by saying it might rain in half an hour.  Those clouds rolling in from the Catalinas (shown below) were great sights for soaring eyes, ones that look to the skies all the time for rain.

5:16 PM. What’s this! Looks like the old Charoleau Gap storm is coming.
5:16 PM. Good base all along the Catalinas, nice and solid-looking
5:57 PM. Bottom of those weak Cumulonimbus clouds have evaporated, leaving moslty virga, and a sprinkle that reaches the ground over there by those mountains but not here.

 

 

 

 

 

 

 

But within the hour, the clouds had broken up, and the shower they produced was reflected by a faint rainbow. Rainbows to the east and northeast are often precursors of rain and wind moving into Catalina. Here is the sad remnants of those albeit weak, Cumulonimbus clouds with their feint rainbow, one that was not followed by one drop of rain here.

A big patch of Cirrus kept the temperature down some during the first half of the day, and so our Cumulus were behind in development compared to areas around us.  Here is that bad Cirrus spissatus in case you missed it, that which hung over us so long.

It was quite visible even in the visible satellite image all morning.  When it shows up there, you can bet that the Cirrus in that image is thick enough to produce shading and mess up the development of Cumulus under and around it, particularly on marginal rain days like yesterday.

Much Cirrus is virtually invisible in visible satellite imagery; get it?  You can see it from the ground (i.e., its visible), those thin wisps of Cirrus, but try to find it in a visible satellite image!  This whole line of reasoning and befuddled exposition here reminds me of that Science knee-slapper of a few years ago; that article entitled, “Where are the invisible galaxies?”

1:49 PM. Cirrus spissatus, sitting there doing nothing, but wrecking out Cumulus clouds.

Today?

Raining lightly now at 5:25 AM! Yay. A night stalker mass of rain is moving into TUS now as I write. They don’t usually like the daytime and fade as the sun rises in the sky. Sprinkles, very light rain showers (and as always pointed out here, quite emphatically I might add, “sprinkles is not DRIZZLE, dammitall”, to be a little colloquial there!).

Let’s hope this heavy cloud cover we have now (5:30 AM), which you could call, Altocumulus opacus and castellanus due to its height above the ground (its at about 11-12,000 feet above the ground and has turrets here and there). But, to get a little pedalogical you could label it in your log book as Stratocumulus, perhaps with the appendage, castellanus, since turrets are present–those are what’s causing the sprinkles/light showers.

Sunset was nice….

U of AZ mod shows this is our best day for a significant rain, some of that this morning, and some arises later with those afternoon and evening giants we get around here. Hoping so.  Tomorrow is supposed to be drier.

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.