Just back from a horsey ride with Zeus the horse. Rode into the CDO to see the surprising view that it had run bank-to-bank last night after that mighty cell passed by along the foothills. In the wash, were golf ball-sized golf balls scattered throughout the wash, indicating that it hit the planned community of Saddlebrooke with it many golf courses very hard. No golfers were found.
The Pima County ALERT gauges really did not call out that such a flow would occur from precip data around here, the greatest amount being barely over an inch, and its likely that such a flow in the CDO, bank to bank would need 2-3 inch dump in its watershed.
———-end of updated material unless I get more updated——
After an afternoon of “steady-state” Cumulus congestus and small Cumulonimbus clouds trailed northward from the Catalina Mountains, the “Mighty Kong” erupted about 5 PM providing one of the most intimidating, yet majestic and beautiful scenes of the summer rain season; this or any.
Cloud Maven Person was indoors drowning his sorrows concerning what appeared to be a a grotesquely failed forecast of a good rain day (“about half an inch”) here in Catalina in flavorful Indian cuisine when the unexpected began to take place outside. So, the photo record is incomplete for this event. “CMP” had given up on the day.
Just measured in NWS-Style 8-inch gauge and CoCoRahs gauge:
0.12 inches was our total here in the Heights.
And, the photos aren’t quite as good as they should be, slightly out of focus since CMP didn’t adjust his camera for the dark scenes his was seeing. Oh, me. Missed the great sunrise, too, due to not having memory stick in the camera! Oh, me.
However this line faded, bringing only sprinkles, a trace of rain to Catalina, and was followed by a huge clearing and sunny skies, thought to be a good thing at the time. Soon, gigantic Cumulonimbus clouds would erupt to over the mountains all quadrants… Nope. By mid-afternoon, only Cumulus congestus had formed with an occasional bit of ice and rain visible, all to the north.
This was the last photo I took until walking out of a local Indian restaurant and exclaiming, “What? When did this happen?” It was so clear to the S-W with the exception of a single dissipating Cb that it didn’t even seem worth a photo.
Well, as it turned out it was a near hit, only 0.06 inches fell in a violent few minutes of huge drops at my place in Sutherland Heights. From what I saw going by, and needing 0.44 inches on yesterday morning’s forecast of 0.50 inches in Sutherland Heights. about 500 yards farther west for this remarkable, dramatic storm would have given us that amount easily. 1.06 inches was recorded at Cargodera Canyon, NE corner of Cat State Park, and several sites in the foot hills of Catalina toward the mountains area had more than half an inch.
A quickie take on a U of AZ model run from last evening’s global data, has Cumulonimbus clouds developing to our southwest and rolling across Catalina in the afternoon. This would be, appropriately, considering the definition of the end of our summer rain season as September 30th, very appropriate.
Some apocalyptic cloud scenes can be Cumulus that explode suddenly into Cumulonimbus, and Cumulonimbus clouds with their foreboding (unless you live in a desert) rain shafts, and their predecessor shelf clouds like “swirly dark Stratocumulus”, and arcus clouds, the latter, a lower line of clouds just above and a little behind the wind shift at the ground, usually just ahead of the main rain shaft. While we didn’t get to see an arcus cloud yesterday, we had some dramatic swlrly dark Stratocumulus clouds to scare us. I say “swirly” because if you looked up yesterday evening as they passed over, you would have seen rotation in them.
These can combine, as they did yesterday, to make you think someone might drop out of the clouds and fix the world1. See those scary photos below, way below as it turns out.
This monster collection of Cumulonimbus clouds (“mesoscale convective system” or MCS in weather lingo) with swirly shelf clouds preceding it barged over Catalina later yesterday afternoon after it appeared that not much was going to happen all day. Heck, there wasn’t even a decent Cumulus over the Catalinas until after 2 PM!
The result of this system slamming Catalina was the usual strong preceding winds roaring down from Charouleau Gap way and points north or northeast. The winds were not as damaging as three days earlier.
Then the rain! So nice! Got 0.55 inches of rain here in Sutherland Heights, an inch and half on Samaniego Ridge, and 1.65 inches on Ms. Lemmon.
Worth watching is the U of AZ weather departments time lapse video, especially beginning at 2 min 50 s into it. That’s when the big group of Cbs begins to make its presence known from the east. What is interesting, and what I have not seen before, is that you will see the tops of a thunderhead farther west, that icy part up around 30,000 to 40,000 feet, shoved backwards (back toward the west) by outflow at the tops of the huge incoming system. Very dramatic.
Detour: detecting ice in clouds….some practice shots
As the burgeoning cloud maven junior person you, of course, know how important the appearance of ice in our clouds is. You got ice; you got precipitation, which is snow up there, soft hail, hail, frozen drops.
Only the largest hailstones up there can make it to the ground as such here in Arizona due to our high summertime freezing levels. The rest melt into raindrops, some of which are large enough to reach the ground. Those downpours that suddenly emit from cloud bases were always hail or graupel (soft hail) aloft.
Sometimes in deep stratiform clouds attached to clusters of Cumulonimbus clouds, and with especially moist air from the base of the stratiform layer to the ground, clusters of ice crystals we call snowflakes make it to the ground without evaporating as steady light or very light rain.
Last night as our storm was coming to an end, it is likely that THOSE drops were once snowflakes rather than soft hail or graupel.
The End (finally)
1Huh. Maybe that wouldn’t be a bad thing. I am very concerned about microplastics (particles 5 millimeters and smaller) in our oceans, resulting from the breakup of larger plastic items we’ve been throwing in the oceans for decades. Seems those tiny particles are getting into everything, including the fish out there! It would be great if someone could get rid of them.
0.48 inches fell after 7 AM yesterday, a nice addition to the 1.83 inches already “in the (raingauge) can”, with a 0.01 inches dollop overnight here in Catalina/Sutherland Heights, slightly more and less here and there, with several inches in the local mountains. That addition brought our storm total to 2.31 inches, about 2.5 times normal for the month of November which averages only 0.96 inches.
Recall that at the beginning of the month, it was deemed by the Climate Prediction Center of NOAA that we in SE AZ would experience below normal precip. But this just shows how HARD it is to predict monthly precip anomalies in semi-arid and arid regions where ONE good storm of just a day or two, can blow the forecast (thank goodness!)
Much harder to blow a monthly forecast in places like Seattle where monthly totals are based on many rain days, and if you only had 25 days with rain in a month instead of 30 due to some storm deflecting pattern, then it might turn out to be a droughty one (hahahahaha, kidding my Seattle reader). Those CPC forecasts have a greater chance of verifying in wetter areas where one rogue storm won’t blow those forecasts up.
Also recall that this season we have no La Nina nor an El Nino to hang our climate forecasting hat on. Makes it tough as well.
If Carl Sagan was a meteorologist today, he would be describing our 2-day November drought bustin’ storm as one worth “billions and billions and billions” where nearly every corner of our drought-impacted State got substantial rains. Should help, too, with wildflower eco-tourism in the spring; at least some wildflower blooms now guaranteed.
Should be a gorgeous day today with deep blue skies punctuated by fluffy Cumulus clouds, some tall enough to form ice and produce virga and light showers here and there; not likely to measure here, though. Lots of Stratocumulus1 around early before breaking up into Cu.
Next rain chance? As November closes out into the first coupla days of December.
Yours and mine; the weather and clouds of yesterday
———————————— 1 Stratocumulus: “flat Cumulus”, a cloud name oxymoron
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