Summer-like storm surprises with frequent thunder and a half inch of rain in 18 min

Here are the latest 24 h totals, ending this morning the 23rd at 3 AM AST from your Pima County ALERT gauge network.  Our own amount over this period is embedded  for comparison purposes:

Gauge         24         Name                        Location
    ID#             hours
    —-     —-       —-        —-       —-         —-       —————–            ———————
Catalina Area
    1010          0.71      Golder Ranch                 Horseshoe Bend Rd in Saddlebrooke
    1020          0.83      Oracle Ranger Station         approximately 0.5 mi SW of Oracle
    1040           0.87      Dodge Tank                   Edwin Rd 1.3 mi E of Lago Del Oro Parkway
    1050           0.59      Cherry Spring                approximately 1.5 mi W of Charouleau Gap
    1060           1.10      Pig Spring                   approximately 1.1 mi NE of Charouleau Gap
    1070            0.79      Cargodera Canyon             NE corner of Catalina State Park
    1080            0.79      CDO @ Rancho Solano          Cañada Del Oro Wash NE of Saddlebrooke
    1100            0.67      CDO @ Golder Rd              Cañada Del Oro Wash at Golder Ranch Rd
xxxx     0.58     Sutherland Heights, Catalina

Santa Catalina Mountains
    1030         1.14      Oracle Ridge                 Oracle Ridge, approximately 1.5 mi N of Rice Peak
    1090         1.34      Mt. Lemmon                   Mount Lemmon
    1110        1.22      CDO @ Coronado Camp          Cañada Del Oro Wash 0.3 mi S of Coronado Camp
    1130         0.87      Samaniego Peak               Samaniego Peak on Samaniego Ridge
    1140         0.79      Dan Saddle                   Dan Saddle on Oracle Ridge
    2150         0.71      White Tail                   Catalina Hwy 0.8 mi W of Palisade Ranger Station
    2280         0.71      Green Mountain               Green Mountain
    2290        0.35      Marshall Gulch               Sabino Creek 0.6 mi SSE of Marshall Gulch

Yesterday, with it many twists and turns, with that significant rain overnight providing a happy, moist beginning.  Then, there was a sad middle of the day when two windshifts passed, the second a major, long-lived one  one bringing a substantial drop in temperature and fronted by a dramatic arcus cloud, but there was no rain to speak of with either……at first.

Then  the surprise, the unlikely resolution of the sad middle of the day just as a dismal clearing advanced from the west:  a highly unusual thunderama and cloud burst beginning at 1 PM, one gushing a half an inch of rain in 18 min!  This,  just when it looked like a total dud was certain from the passage of that front.  That  “TRW++” (weather text for an extra heavy thunderstorm),   provided the happy ending, thus making it a day truly out of Hallmark.  The total rain was 0.58 inches, with the three day total at 1.03 inches!  Yay, flower help!  Rain table at bottom.

Though it was late December and at the winter solstice, the breezy 63° F damp air yesterday morning made it feel like you had awakened from your long vacation flight and found yourself in Hawaii or Miami.  It was a truly remarkable, even a joyful feeling.

With that strong upper low WAY off to the southwest of us yesterday morning,  and moving right this way, you KNEW that the rain wasn’t over, that thought adding to the joy of yesterday’s early morning.  0.34 inches had fallen mostly during the night before, adding to the humid feel.

Too, yesterday morning’s joy had a withering effect on all those dry weeks that had preceded these past few days with measurable rain,  maybe even withering the hard feelings that remain in many of us about those disappointing Big Niño forecasts of a wet Southwest last year.  You were finally  beginning to feel that you could  let go of those hard, grinding, grudge-holding feelings you had against  weather forecasters, the ones that  misled us so much last year about the Big Winter in the Southwest due to the Big Niño, a record Niño,  they told us, indeed, a “Godzilla Niño.”    Then, what followed was, “The Big Winter that Didn’t Happen.”  And it will be years before we get another Big Niño!

But, let us move on from that tirade to current events; you can see that I am personally completely over the hard feelings of last year’s disappointing forecasts and have moved ahead,  as we need to do in life…

Now, finally (!), for yesterday’s clouds, so fantastic in all their presentations and drama, that one really could finally forget the busted Big Niño forecasts of last year2:

Oh, yeah, the cloud diary for yesterday, probably more than you need to know, but, what the heck:

DSC_0179
7:56 AM. A shower complex heads north toward Catalina, only to graze the city.
7:57 AM.
7:57 AM.  Stratocumulus clouds topped Sam (Samaniego) Ridge as that shower approached, the lower bases telling you how humid the air was.  Dewpoints were in the low 50s!
8:04 AM. Gettin' closer, gettin' pumped for a nice rain blast in tropical air!
8:04 AM. Gettin’ closer, gettin’ pumped for a nice rain blast in tropical air!
8:22 AM. That complex of rain mostly slud off to the east of us, as so many have this year. However, note the lack of good shafting, just rainy areas that are a little thicker and thinner. This tells you that they're really not Cumulonimbus clouds, but rather shallow ones not having strong updrafts. Earlier, it appeared to be a complex with a Cumulonimbus in it, and in that case, you would see strong shafting.
8:22 AM. That complex of rain mostly slud off to the east of us, as so many have this year. However, note the lack of good shafting, just rainy areas that are a little thicker and thinner. This tells you that they’re really not Cumulonimbus clouds, but rather shallow ones not having strong updrafts. Earlier, it appeared to be a complex with a Cumulonimbus in it, and in that case, you would see strong shafting.  Wonderfully dismal scene, I suppose to those of you with normal sky values;  sunny and blue are just fine.  Those of you with sky values like that might just as well get the HELL off this page right now!  There’s a lot more dismality ahead, except maybe for the next couple of photos…
10:24 AM. Sky breaking out more and more, probably some non-cloud maven people exulting over the clearing. But, it was still moist and humid, and no real windshift had occurred, something that woud presage descending air behind it, and a true clearing. Indeed, true cloud maven folk were exulting over the clearing since with the low aloft approaching, some warming of the ground might lead to real Cumulonimbus clouds while the air aloft was cooling!
10:24 AM. Sky breaking out more and more, probably some non-cloud maven people exulting over the clearing. But, it was still moist and humid, and no real windshift had occurred, something that woud presage descending air behind it, and a true clearing. Indeed, true cloud maven folk were exulting over the clearing since with the low aloft approaching, some warming of the ground might lead to real Cumulonimbus clouds while the air aloft was cooling!  In this photo are Cumulus humilis and fractus (down low, darkish cloudlets) a riff of Altocumulus castellanus (indicating mid-level instability) and above those, a separate layer of Altocumulus with ripples (“undulatus”), and maybe Cirrocumulus adjacent to the higher Ac clouds.  A Cu fattening on  calories of sunlight can be seen on the horizon, center.  I hope I can be done with this cloud story before dark today….
10:22 AM. Here we go! A line of Cumulus congestus and "soft-serve" Cumulonimbus clouds HAS to be associated with a windshift line. Its got to come through Catalina. This view is looking to the NW. Such a band is likely to extend to the SW from here, and beyond the SW horizon, so you won't see it yet over there.
10:22 AM. Here we go! A line of Cumulus congestus and “soft-serve” Cumulonimbus clouds HAS to be associated with a windshift line. Its got to come through Catalina. This view is looking to the NW. Such a band is likely to extend to the SW from here, and beyond the SW horizon, so you won’t see it yet over there.  Altocumulus perlucidus clouds overlay Catalina at this time along with a few puffs of Cumulus fractus.  Its still humid.
11:44 AM. Pretty scene of course, but look carefully on the horizon below the bases of the clouds and you will see arc-shaped clouds curving back toward the NW. THis view is to the SW. Those arc-shaped clouds are that windshift line where air converges to form a line of clouds as was seen in the prior photo. Too many invervening clouds prevent seeing a line here, but as a cloud maven junior or expert, you know there will be a LINE! We hope to have a lot of good testomonials at the next club concerning who saw these arched clouds first.
11:44 AM. Pretty scene of course, but look carefully on the horizon below the bases of the clouds and you will see arc-shaped clouds curving back toward the NW. This view is to the SW. Those arc-shaped clouds are that windshift line where air converges to form a line of clouds as was seen in the prior photo. Too many intervening clouds prevent seeing a line here, but as a cloud maven junior or expert, you know there will be a LINE! We hope to have a lot of good testimonials at the next club concerning who saw these arched clouds first.  Right here, you KNEW something dramatic was about to happen to the sky, and almost certainly something to your rain gauge as well.
12:25 PM. Here it comes! No telling how many inches we might get! (However, the shafting looks weak to me... Not congruent with big "Cumulonims" with good updrafts....so some doubt creeping in.)
12:25 PM. Here it comes across the OV! No telling how many inches we might get! (However, the shafting looks weak.. Not congruent with big “Cumulonims” with good updrafts in them….so some doubt beginning to creep in.)
12:31 PM. I feel like I am in Louisiana or Alabama awaiting a cold front. THis was SUCH a dramatic scene, I know you were having a hard time constraining yourselves, and not running to tell neighbors about it.
12:31 PM. I feel like I am in Louisiana or Alabama awaiting a cold front. This was SUCH a dramatic scene, I know, like me,  you were having a hard time constraining yourselves;  not running to tell neighbors about it.
12:32 PM. Zooming in on a fantastic scene for Arizona! Camera can't fire fast enough!
12:32 PM. Zooming in on a fantastic scene for Arizona! Camera can’t fire fast enough!  I was getting light-headed here.
12:39 PM. The windshift to the NW has passed the house, but those arched clouds above the windshift are getting pretty ragged. And where's the rain?
12:39 PM. The windshift to the NW has passed the house, the temperature is dropping like mad, but those arched clouds above the windshift are getting pretty ragged.  And where’s the rain?  Pretty scene, though.
12:45 PM. Within a few minutes, a few hundredths of an inch fell, propelled on gusty NW winds, but then it quit, the low clouds banked up harmlessly against the Catalinas, which still had sun on them! This was looking really bad. No rain was in sight, either.
12:45 PM. Within a few minutes, a few hundredths of an inch fell, propelled on gusty NW winds, but then it quit, the low clouds banked up harmlessly against the Catalinas, which still had sun on them! This was looking really bad. No rain was in sight, either.  Pretty scene, though.  We don’t want to lose sight of beauty when its in front us, even when we’re getting sad about the turn of developments, which in a Hallmark movie would be that point when the owner of the building that a bakery or flower shop is in, says he has to lick them out because he has sold the building.  Yep, that’s how bad it looked right at this point.
12:50 PM. The arcus clouds and windshift had moved in from the west, and so this clearing out there HAD to be approaching, the day's rain likely over. I can only imagine how glum you all were out there in seeing this abyssal scene, "sunny skies just ahead", spoken sarcastically.
12:50 PM. The arcus clouds and wind shift had moved in from the west, and so this clearing out there HAD to be approaching, the day’s rain likely over. I can only imagine how glum you all were out there in seeing this abyssal scene, “sunny skies just ahead”, spoken sarcastically.
12:53 PM. The Stratus clouds now hung even lower, as though wanting you to touch their empty innards, a truly humiliating scene. I have never seen such vacant clouds, so filled with portent only minutes before. This was, indeed the low point of the day.
12:53 PM. The Stratus clouds now hung even lower, as though wanting you to touch their empty innards, a truly humiliating scene. I have never seen such vacant clouds, so filled with portent only minutes before. This was, indeed the low point of the day.  The sun would soon burn them off.
1:02 PM. Just after the most amazing thing, a blast of THUNDER overhead E or SE, And, it was starting to rain! But here you can see lower clouds (Stratus or Cumulus fractus) that are separate from a higher layer (top). So, where the HECK was the Cumulonimbus?
1:02 PM. Just after the most amazing thing;  a blast of THUNDER overhead E or SE, And, it was starting to rain! But here you can see lower clouds (Stratus or Cumulus fractus) that are separate from a higher layer (top). So, where the HECK was the Cumulonimbus?
1:09 PM. Heart of the blast, visibility is less than a quarter mile, thunder, close to overhead it seemed, had become more frequent, once every minute to two, unheard in winter storms. It almost exactly the intensity of our summer ones. Completely out of control here snapping photos of nothing but rain, hoping camera battery doesn't give out. But, then I know I would have had company with all of the CMJ's out there losing your minds over this as well. What a day, Mr. and Mrs. Catalina!
1:09 PM. Heart of the blast;  visibility is less than a quarter mile, thunder, close to overhead it seemed, had become more frequent, once every minute to two, unheard in winter storms. This winter storm, on the solstice, was almost exactly the intensity of our summer ones. Completely out of control here snapping photos of nothing but rain, hoping camera battery doesn’t give out. But, then I know I would have had company with all of the CMJ’s out there losing your minds over this as well. What a day, Mr. and Mrs. Catalina!   Is this what “global warming” has ahead for us, as one Arizona scientist mused?  Summer-like storms in the heart of winter?  Maybe it would be so bad….  Hardest rain I’d seen here in nine winters.
1:18 PM. A few hundred photos, 18 min, and a half an inch of rain later, I ventured out to see what was the result. Here, ponding had occurred in a swale. I wondered whether toads would re-emerge after this warmish rain?
1:18 PM. A few hundred photos, 18 min, and a half an inch of rain later, I ventured out to see what was the result. Here, ponding had occurred in a swale following the gush.  Considering the warmish nature of the rain, would toads now re-emerge along with flying ants?
4:42 PM.
4:42 PM.  One of the rewards of clearing skies, are the quilted-with-sunlight mountains sides of the Catalinas.
4:43 PM. While plump Cumulus clouds and dark skies abounded, these clouds no longer reached the level where ice could form, and were "dry" clouds as far as precip goes.
4:43 PM. While plump Cumulus clouds and dark skies abounded, these clouds no longer reached the level where ice could form, and were “dry” clouds as far as precip goes.
4:51 PM. Highlight toward the Gap.
4:51 PM. Highlight toward the Gap.
5:16 PM. More evening color; note rain gauge.
5:16 PM. More evening color; note rain gauge.  Such a pretty scene!

 

The End

New storm marches toward Catalina!  Due in tomorrow afternoon.

1Meteorologists, outside of Buffalo and Seattle,  have inverted values regarding clear and cloudy.

2I hope we get 30 inches THIS water year, dammitall, busting this year’s seasonal forecasts of a  dry Southwest.

 

 

Author: 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.