Altocumulus clouds, Cumulus clouds, Definitions, Rainbows, Virga

Rare “Geo-Astro-Meteo Conjunction” captured on film!

Well, it used to be film….

Blobs of sprinkle clouds pummeled Catalina yesterday beginning soon after 12 Noon and ending only after 7 PM when an extraordinarily rare “Geo-Astro Meteo Conjunction” (GAMC)  was observed due the conjunction of a rainbow, a moonrise exactly over Mt Lemmon, and the top of Mt. Lemmon itself visible through rain.   The GAMC “trifecta” scene, is thought to occur only once every several hundred years.  The duration of yesterday’s scene  was about 3 minutes, the cloud with the rainbow having produced a sprinkle here just prior to the rare scene.  Only more rare than the GAMC is a sunrise exactly over the crest of Mt. Lemmon with a rainbow in the direction of the sun.

Three sprinkle periods were recorded yesterday, the longest between 5:43 and 5:45 PM.   The others occurred at 12:28-12:29 PM, and 7:26 to 7:27 PM.  The rain brought June’s monthly total to a trace, ending the prospect of a completely rainless month.

No accidents were reported due to excited motorists reveling in the “rain” on their windshields, having attention diverted from driving.  Local meteorologists explained that higher dewpoints than expected allowed a few drops to reach the ground instead of evaporating completely from the high-level virga that had been forecast earlier.   The higher dewpoints allowed cloud bases from which the virga fell,  to be 100 millibars, or about 4,000 feet, lower than computer models had predicted.  The meteorologists blamed a lack of data far upwind of Catalina for the forecast gaffe.

Below, a rare GAMC, one that you will like not see in your lifetime if you did not see it yesterday:

7:28:26: A Trifecta scene is observed toward Mt. Lemmon (the rounded hump below the moon). This scene can only occur with the rain and sun in proper positions to produce an arc of a rainbow over Mt Lemmon, but the rain must be light enough so that neither the moon nor Mt. Lemmon are obscured in any way. Yours, today only, for $1,000,000.
7:28:26: A truly rare GMAC scene develops toward Mt. Lemmon (the subtle, rounded hump below the moon). This scene can only occur with the rain and sun in proper positions to produce an arc of a rainbow framing Mt. Lemmon, but the rain must be light enough so that neither the moon nor Mt. Lemmon are obscured in any way. Yours, today only, for $1,000,000.

 

Moving on…..yesterday’s clouds

6:33 AM. Pretty Altocumulus, fatter version of "perlucidus." Didn't look to be as interesting a day as it turned out to be. This layer was about 12,000 feet above the ground.
6:33 AM. Pretty Altocumulus, fatter version of “perlucidus.” Didn’t look to be as interesting a day as it turned out to be. This layer was about 12,000 feet above the ground.
12:38 PM. Some Cumulus begin forming underneath the sprinkle clouds (ice visible on the bottoms of the Altocumulus clouds on the left.
12:38 PM. Some Cumulus begin forming underneath the sprinkle clouds (ice/virga visible on the bottoms of the Altocumulus clouds on the left–that made the bottom smooth.)
1:17 PM. Gorgeous example of Altocumulus castellanus (no ice/virga).
1:17 PM. Gorgeous example of Altocumulus castellanus and floccu (no ice/virga).

 

5:30 PM. Cloud complex of the day, loaded with sprinkles, CMJs were predicting that sprinkles, and ONLY sprinkles, were about 5-10 min away.
5:30 PM. Cloud complex of the day, loaded with sprinkles, CMJs were predicting that sprinkles, and ONLY sprinkles, were about 5-10 min away.
5:46 PM. Following the sprinkle, eyes should almost automatically turn to the east for a some rainbow eye candy.
5:46 PM. Following the sprinkle, eyes should almost automatically turn to the east for a some rainbow eye candy.
7:37 PM. The pretty cloud day closed out with a satisfying sunset.
7:37 PM. The pretty cloud day closed out with a satisfying sunset.

The weather ahead

Today looks like it will be pretty much like yesterday, lots of mid-level clouds cold enough for virga, as you can see out there right now (just after sunrise), supplemented by afternoon Cumulus. Altogether another pretty day with reasonable temperatures held down by clouds and virga around. We’re on the edge of this mid-level moist plume coming up out of the Tropics, BTW. Rain is foretold by the quite wonderful U of AZ Beowulf Cluster calculator to only fall in the SE corner of the State today.  This from last evening’s 11 PM AST data.

The later model runs have had potent Hurricane Crissy’s moist plume missing us to the east now, so don’t really want to talk about it.  Winds in Cristina now 145 mph sustained as it rapidly intensified from yesterday’s 75 mph.  Should mean good surf along the west coast of Mexico and a certain south-facing southern California beach haunt of CMP,  called, “Zuma Beach”, where the acclaimed dramatic series, “Baywatch” was first filmed.

The End.