We received 0.08 inches here in “The Heights” for a third day with measurable rain in May already. 0.12 inches fell at the Bridge on Golder Ranch Dr. , while Saddlebrooke got up to a quarter of an inch (as estimated by CMP) in a tiny streak of clouds that erupted into shallow Cumulonimbus clouds, anvils and all yesterday afternoon between 4:30 and 5:30 PM. It was pretty much all over by 6:00 PM, those shower clouds passing off toward Mammoth.
No rain was reported at mountain sites, to give you an idea of how localized that was, localized practically to Basha’s Market parking lot, Sutherland Heights’ Equestrian Trail Road, and Saddlebrooke’s Acacia Drive, to exaggerate some.
The astounding aspect of a tiny line of showers that suddenly erupted over and a little downwind of Catalina was that it was EXACTLY predicted in the University of Arizona’s 5 AM AST model run yesterday morning, one whose results are available by mid-morning! So, there would have been a few hours notice of possible rain here in Catalina.
There is no rain predicted in that model run anywhere else except in extreme NW Arizona, just that tiny ribbon of rain right over us, and the U of AZ “Beowulf Cluster” weather calculator got it right.
However, unless you were in the right spot, you might not have even known that it rained, the shower streak was so narrow.
To be “fair”, NO RAIN was predicted anywhere NEAR Catalina by that same model crunching the data from 5 PM AST the evening before our little rain event, leading CMP to be a little asleep at the wheel yesterday morning, no blog.
Some cloud shots before and as this predicted (or unpredicted, as the case may be) rain began to happen. Of course, if you want to go to the movies and see this, go here, from the U of AZ: Yesterday’s cloud movie
Below, sat view of this cloud streamer with radar, from IPS MeteoStar. The image below is at the same time as the last photo above:
Here some more cloud stuff from the sounding launched at the U of AZ around 3:30 PM AST.
Here’s a diagram of when ice forms in the type of clouds we mostly have in Arizona, “continental” ones with high droplet concentrations, and when ice should form in them. As you can see, ice should form in them soon after the top temperature gets colder than 10 C WHEN the base temperature is about what it was yesterday.
“CMP” is not mentioning it at all, but yesterday was another kind of mucked up sky, not a Catalina postcard sky, with lots of aerosols making the sky a whitish-blue, the lower aerosol stuff again from Mexico, but there was also a layer far above the cloud tops, likely a long-range transport event from thousands of miles away.
This higher haze layer still seems to be around if you look toward the horizons right now (5:59 AM).
We’ll be between two jet streams today, kind of a jet stream sandwich, and the stronger one is now approaching from the northwest with that mega upper low over Cal. That means no rain today, subsidence rules, though we’ll have small, non-ice producing Cumulus, and likely some Altocumulus lenticulars, maybe a Cirrocumulus patch here and there. Should be a pretty nice day for cloud photos, haze aside.
The best chance for rain is still after midnight tonight into mid-day tomorrow as the core of the stronger jet stream goes just about over us. Still thinking a tenth of an inch will occur here, though mod run from the U of AZ at 5 PM completely dry. A little snow likely on Ms. Mt. Lemmon, too!
The End, FINALLY! Brain empty.