Happened around noon yesterday. I could see it from here that the shaft consisted of graupel mixed with some rain. Nice video of this exceptionalism-of-the-day event here from the U of AZ.
Its interesting to me, and to you, too, most likely, was that yesterday it was asserted here that there would be no ice in the “small” Cumulus clouds that were expected to form during the day. And yet we had a momentary Cumulonimbus cloud with a ton of ice and a graupel/rain/snow shaft! Huh.
In related1 distractive headlines:
Fields of gold erupt in Catalina!
Hours: 10 AM to 3 PM, M-S, otherwise closed. Why do they do that? You won’t find the answer here, so move along now…
Yesterday’s clouds and explanations
12:29 PM. Total icy humiliation. The “cotton candy” transition of the prior turret to “Mr. Frosty” (left of center) was complete for all to see. Looking toward Catalina, I could almost hear the laughter, “Calls himself a ‘cloud-maven’, said there wouldn’t be any ice today, and look at all that ice! What joke!” Now that the turret has become a modest Cumulonimbus, likely completely glaciated, the precipitation falling would be snowflakes (not graupel since the liquid water droplets are gone inside it) melting into rain farther down.
1Its not really related but sounds like something that should be said.
While living the big western life yesterday by riding a horse, me and my ridin’ pal, Nora B., came across some water flowing in the Sutherland Wash by the rusty gate on the east side of the wash that leads to Coronado National Forest land.
So, with with a 3-5 inch rain on the Catalinas, there WAS some water in the Sutherland here in the Catalina area. It was remarkable that there was no sign whatsoever of water having flowed at the Cottonwoods at the Baby Jesus Trail head on the north side of this flow (shown below), but water was flowing in it a few hundred yards farther downstream.
Nor was there any sign that water had flowed from our big rain in the Sutherland Wash at the back gate to Catalina State Park. In fact, we saw where this Sutherland Wash water disappeared just down from the rusty gate.
So, a lesson has been learned here about wash water flows: it can be flowing modestly between two dry points. Huh. Might not see this again for some time, and it will all be going away soon. Too bad so many of us have to pass hiking or horseback riding to these rare scenes today due to a necessary Pac 12 football TEEVEE vigil beginning just after 12 noon today and lasting through midnight I think. Kind of sad when you have to make choices between two equally worthy activities like these.
Cloudwise, I hope you logged the occurrence of distant Cumulonimbus clouds in the high country on the NW-NE horizon late yesterday afternoon.
Sure, there was a little mischievous wind in the early afternoon, BUT, as a day in late May in Catalina/Sutherland Heights zone of Arizona, wherein the temperature is less than 100 F, well, it was pretty darn great. Another one is on tap today just like yesterday today, too. Feeling sad about the early, northerly ejections of “snowbirds” who thought because of the warm winter, May would be an inferno here and are missing some splendid weather. Doesn’t work that way. You just don’t know.
Lot of interesting clouds yesterday, too, real cold ones. Those Cumulus that formed in the late morning and afternoon started producing ice almost immediately. Wonder if you caught the first ones over there beyond the Charouleau Gap around 11 AM? They did not look as high-based as they were, thus, as cold overall, dad-gum, those cloud bottoms were running around -10 C (14 F)!
How high off the Catalina ground were they? Oh, about 13,000 feet, or about 16,000 feet above sea level (about 550 millibars). I woulda guessed, as you would have, about 8,000 feet off the ground when I first saw them forming (and not looking at the temperature and dewpoints, from which you can make a pretty good calculation of the cloud base height). From the Cowboys at the U of Wyoming, this sounding for TUS yesterday afternoon:
Weather Hints for Every Day Use by “Art”: You can calculate the height of a Cumulus cloud base by taking the difference between the temperature and the dewpoint, dividing it by 5, square that number, add the number you started with, and subtract the square root of 2.
DId I get the number you started with?
(Actually, stop at “dividing by 5”, multiply that number by 1000, and you’ll come out just about right. Yesterday, 85 F temp, 20 F dewpoint, leads to 65 F difference, divide by 5, you get 13, and times a thousand is an estimated CUMULUS cloud base of about 13,000 feet above you, not too bad).
Continuing….. Since bases were so cold, tops were exceptionally cold, too, for shallow Cumulus and started producing ice when they were only about 1,000 to 3,000 feet thick, with cloud top temperatures of -15 C to -20 C (about 4 F to -4 F). Some of the highest tops, all east of us, and mostly on the east side of the Catalina Mountains, were likely as cold as -30 C (-22 F).
You may also have noted in your cloud diary the bifurcation in the Cumulus array of yesterday. Almost no Cumulus west of Catalina, and plenty in the east half of the sky, appearing to be largest in the distance in the east. We were literally on the edge of the moist plume from the south that was hoped to end up been west, with us deeply embedded in it, and where measurable rain might have fallen here as it did east of us yesterday. Oh, well.
Today, with a low center passing over us tonight and a blob of Pacific Ocean air in it, and while that air is cold and pretty dry aloft, it will be a little more moist and so cloud bases today should be a little lower, and warmer, than yesterday’s. That means a little more water condensing in them than in yesterday’s clouds, and a greater chance of sprinkle here. Hoping for measurable, but its probably less than a 50-50 shot at that. Likely will be some thunder in the area of SE AZ, too. And, as always with high cloud bases, gusty winds that arise due to virga and rain falling through the dry air below cloud base. (Yesterday afternoon’s gales in the Sutherland Heights, momentary blasts of 40-50 mph, were NOT due to virga, but a rather to something I didn’t see coming, maybe a smallish low center–nothing really showed up on the maps.)
You will also see in the above loop that our low takes its time moving along, and will keep the skies interesting with Cumulus and weak Cumulonimbus clouds today and tomorrow, along with temperatures below seasonal norms for late May (aka, less than 100 F) ((Snowbirds left too soon; ice still melting off some areas of the Great Lakes!))
From the cloud vault; yesterday’s clouds
The weather ahead and WAY ahead
Now what I think is really interesting, which is almost everything to do with weather, is that the models are suggesting a tropical injection again at the end of MAY into early June, with a chance of a decent rain again. As you can see in the plot below from the NOAA spaghetti factory, a trough to the west of us and over California is a virtual certainty now at the end of May. That means the air above us will be, while quite warm, originating from the deep Tropics with the likelihood of clouds and precip coming up from there. Nice. Will keep me posted on these developments, in case no one else is reading this far.
Still a chance, a small one for a shower today, before it dries out for a few days. Mods pretty sure about rain on the Cats this afternoon, which is good. Should be a very photogenic day, with nice shots of more isolated thunderblasters.
With that out of the way…let us reprise yesterday, the good and the bad.
Only 0.17 inches here in Sutherland Heights yesterday while Saddlebrooke was getting shafted, rain shafted, that is. Moore Road at La Cholla, over there, also got more than TWO inches yesterday afternoon. You can check the interesting amounts here and here.
Another near miss here at the house. May have to sell if this keeps up. July rain here in Sutherland Heights, now at only 2.87 inches (normal is 3.5 inches) while everywhere within radius of two miles has more, for example, about 3.5 inches already over there to the south on Trotter (just S of Golder Ranch Drive), and 4 or so inches in places in and around Saddlebrooke, almost within ear shot.
Here are the effects of more July rain than here; these shots from yesterday morning down in the Regional State Park next to Lago del Oro Road:
Continuing with vegetation shots after nostalgia break:
Also had a surge down the CDO wash. I know you like to see this, you love water, so here are two shots from yesterday afternoon after the Saddlebrooke mash down:
While the rain was a disappointment, all the other scenes yesterday caused more than 200 photos to be taken from it. Since I have termed myself, rightly or wrongly, as a “cloud maven”, I should show you ones I thought were exceptional, pretty and or dramatic. The first one, while I was looking forlornly at the Saddlebrooke cloudburst, “Why there, and not on me?”:
Here’s what rips your heart out, the big, smooth-looking base indicating a good updraft right overhead but nothing comes out. The giant drops, those ones that are the biggest ones in the cloud could be coming down, defeating the updraft that’s been holding them up there because they’ve gotten too big and heavy for it, and likeyly they were even were big hail stones or giant graupel particles (soft hail), and they’re up there. but the strands of those biggest drops begin to streaming downward just a mile away you see. First, you have some sky rage seeing those strands reach the ground just a mile away, your face reddening, but then, being by nature more contemplative, resign yourself to yet another miss as now the sky fills with dead looking debris cloud upstream of you, only producing light, steady “little baby” rain at best, rain that wouldn’t amount to that much, only might be important to a flying ant colony, but that’s about it. Heartbreak Hotel, right here, overhead yesterday, started thinking about moving on again:
Thought back, too, to all the promise, the propitious start to the day with those thunderheads, mimicking hydrogen bomb blasts, over the Mogollon Rim on the north horizon at 9:30 AM. As a cloud maven junior, you would been thinking, “THIS is going to be a special day today.” Here’s that distant scene, so fabulous to see, from Equestrian Trail Road: