Storm disappoints with only 0.10 inches in Catalina

Oh, well.  Was expecting at least 0.25 inches a few days ago, and thought maybe a heavy shower last night might pull that expectation out of the trash bucket.  Monthly total now up to 0.70 inches (updated after reading NWS-style and CoCo gauges here), still significantly below average (0.96 inches). Not much else elsewhere, either.  Double dang.

Mostly Cumulus humilis and flat Stratocumulus yesterday.   Was looking for ice as the temperatures aloft cooled during the afternoon and evening, and only as the sun went down was a slight bit of virga visible to the west.  That Stratocu deck over us was deepening upward, and began reaching the magic point where ice begins to form, probably around or a little below -10° C (14 °F)  in clouds such as yesterday’s.  Let’s look at a sounding from the U of AZ (as displayed by IPS MeteoStar) and see what it says about those evening clouds and see if the above is just a bunch of hooey (I haven’t seen it yet, either):

The TUS sounding launched about 3:30 PM from the University of AZ campus. Suggests the cloudy air on that side of the mountains was indeed reaching to -10° C and likely a hair lower in the slightly higher cloud tops. Our tops especially a bit later and being a little northwest of there, were surely a bit colder.
The TUS sounding launched about 3:30 PM from the University of AZ campus. Suggests the cloudy air on that side of the mountains was indeed reaching to -10° C and likely a hair lower in the slightly higher cloud tops. Our tops especially a bit later and being a little northwest of there, were surely a bit colder.

Yesterday’s clouds

DSC_9499
9:31 AM. Nice scruff of maybe Stratocumulus lenticularis topped Ms Lemmon, and indication of the lower level moistening that took place overnight with a dry front going by, with another one on the doorstep.  Gee, camera lens is dirty.
2:45 PM. Not much going on, just a few Cu hum, "two riders were approaching and the (cold) wind began to howl." Bob Dylan, from "All Along the Watchtower" by Jimmi Hendrix.
2:45 PM. Not much going on, just a few Cu hum, “two riders were approaching and the (cold) wind began to howl.” Bob Dylan, in “All Along the Watchtower” by Jimmi Hendrix.   Nobel Laureate Bob wrote a LOT of songs about weather!
The Mighty Fraidy Cat Zeus, waiting for the weather to change, the clouds to fill in. Today's blog is particularly boring so thought I would spice it up with a horse that saw a tire up against a horse fence, twirled around and at a full sprint, as though being chased by a Tyrannosaurus rex, plowed into a clump of tall cat claw acacias and mesquite bushes. CMP came off in the midst of them, racking up a broken rib, and a lot of scratches, and with all that blood on his long sleeved shirt, walking Zeus back, also racked up quite a few "man points" by passersby. Well, there was one passerby who didn't seem to notice as they drove by and I had to scream, "I'm OK! Its nothing, really!"
2:47 PM.   The Mighty Fraidy Cat Zeus, waiting for the weather to change, the Cumulus clouds to fill in. Today’s blog is particularly boring so thought I would spice it up with a [icture of a large (16.2 hands) horse that saw a tire leaning up against a horse fence, twirled around and at a full sprint, as though being chased by a Tyrannosaurus rex, plowed into a clump of tall cat claw acacias and mesquite bushes.   The first second of that bolt was really exciting and fun, the second second, not so much.  CMP  was knocked off in the midst of them, racking up a broken rib, and a lot of scratches that bled profusely.  However,  with all that blood on his long sleeved shirt as he walked the mighty Zeus back to his corral, also chalked up quite a few “man points” when passersby saw him, I am sure.    Well, there was one passerby who didn’t seem to notice as he drove by and I had to scream, “I’m OK! Its nothing, really!”
2:48 PM. Nice lighting. I don't know how many hundreds of these shots I have posted here. I just never get tired of sunlight and shadows on our mountains!
2:48 PM. Nice lighting. I don’t know how many hundreds of these shots I have posted here. I just never get tired of sunlight and shadows on our mountains!  Clouds still not doing anything, but its only been a minute since the last report.
3:11 PM. Now we're talking! Those Cumulus clouds are beginning to expand, fill in, transitioning to a Stratocumulus broken to overcast sky, a Stratocast, as expected as the next front and trough approached. This was exciting.
3:11 PM. Now we’re talking! Those Cumulus clouds are beginning to expand, fill in, transitioning to a Stratocumulus broken to overcast sky, a Stratocast (nomenclature unrelated to Fender guitars), as expected as the next front and trough approached. This was exciting.  But when will the ice form in them  to give us the first virga and precip?
3:53 PM. Looking SW over the Oro Valley. This is really looking good. In situations like this, the clouds are forming as they travel upslope toward the Catalinas, and while they're not preciping now, its fairly common in the situation we had yesterday for them to start preciping as the tops get chillier and chillier, often with the clearing remaining in place to the SW. That's what I thought might happen. Things were changing fast at this time.
3:53 PM. Looking SW over the Oro Valley. This is really looking good. In situations like this, the clouds are forming as they travel upslope toward the Catalinas, and while they’re not preciping now, its fairly common in the situation we had yesterday for them to start preciping as the tops get chillier and chillier, often with the clearing remaining in place to the SW. That’s what I thought might happen. Things were changing fast at this time.
5:15 PM. Virga and light precip were occurring on the horizon NW-NE, and these heavier Stratocu began to virga a few minutes after this. The anticipation? A nice period of light to moderate rain during the early nighttime hours as this deepening and filling in continued. That didn't really happen. The clouds began to rain lightly here, but it didn't measure. It was a another band coming through before midnight that produced the 0.08 inches.
5:15 PM. Virga and light precip were occurring on the horizon NW-NE, and these heavier Stratocu began to virga a few minutes after this. The anticipation? A nice period of light to moderate rain during the early nighttime hours as this deepening and filling in continued.
That didn’t really happen. The clouds began to rain lightly here, but it didn’t measure. It was a another band coming through before midnight that produced the 0.08 inches.
5:24 PM. I know a lot of you like to see pictures of the sun, so I thought I would post one today.
5:24 PM. I know a lot of you like to see pictures of the sun, so I thought I would post one today.  Looks pretty round, a little bigger than usual.  Don’t see any sunspots (defects) on it.  That’s probably good.
5:30 PM. Just after sundown the virga began to emit from this layer just beyond the Tortolitas. Really thought this would lead to a generous rain with continued deepening. Guess that didn't happen.
5:30 PM. Just after sundown the virga began to emit from this layer just beyond the Tortolitas. Really thought this would lead to a generous rain with continued deepening. Guess that didn’t happen.  Probably only the best virga detectors among you saw this little curtains starting to descend from this cloud deck.  I’ve added arrows to where those two patches of virga are.

Still looks like a chance for some light showers before the month closes out, but will be hard to get enough to bring the total to an above average value.  Dang.

Will update my reader on December’s early cold outlook as new information that agrees with my assessment comes in.  Right now, that information is not available.

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.

2 comments

    1. Yep…. Last evening I was sure that Sc was deepening up to produce a nice evening rain of a quarter inch or so! Nope.
      Maybe “Cloud Maven” isn’t as much of a “maven” as he claims to be. haha, sort of.

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