What an amazing and “productive” little rainband that was just after midnight! And more rain is likely with weaker bands just upwind here at 4 AM. Could we really approach an inch? Amazing. Didn’t seem possible in this small mind that we could amass that much. For a full regional rain table, go here to the ALERT gauge records.
Now, after this ends, a long dry spell has to be endured, at least until around the 20th of Jan, at which time we hope the troughs and rain threats at least, will begin to barge in every few days, namely, and pattern more typical of winter sets in.
Yesterday’s clouds
8:31 AM. Typically lenticular clouds form in the lee of the Catalinas as storms approach. Lenticular clouds are good signs of deteriorating weather ahead since they are usually accompanied by strong, moistening winds aloft.8:31 AM. Zoomed view of one lurking just beyond the crest of Ms. Mt. Sara Lemmon. The higher clouds were Cirrus (which can have grayness when the sun is low).10:24 AM. Wasn’t long before this deck of Stratocumulus raced over the sky, adding that feeling that rain is a comin’.11:32 AM. Some tendency to form the new supplementary cloud feature, termed, “asperatus undulatus” is shown here at the base of the Stratocumulus deck.1:13 PM. Got excited when ice began to show up, with virga and light rain showers here and there. Can you see that icy top receding from the Catalinas? It wasn’t that high and cold, either.1:14 PM. Nice highlighted view of Biosphere 2, with light rain showers in the background. Whodda guessed Bio2 would get 1.93 inches overnight? Not me!1:59 PM. Light rain showers began to fall from that Stratocumulus layer, now pocked with buildups (Stratocu castellanus?) as temperatures aloft above cloud top cooled. The haze is due to rain falling from overhead. It did not measure.1:59 PM. Looking upstream and the Stratocumulus deck whose tops were just ascending to the ice-producing level as they approached Catalina from the SSW. That clearing on the horizon maintained throughout this cloud and shower period suggesting it was caused soley by the lifting of the air as it approached the higher terrain of Catalina and the mountains. It was soon to disappear.3:02 PM. Falling apart.3:49 PM. Gone. Yes, once again, the clearing before the storm. A storm is approaching, 100% chance of rain within 10 h, and yet, the clouds are disappearing! This is a common here; a dry slot in the moisture field OFTEN precedes storms here. To some folks it may mislead them into thinking the storm’s a bust. But not to us CMP’s, who seen this happen over and over again.5:09 PM. Temperature’s in the low 70s; its getting to be a nicer day by the minute. Where’s that storm?5:43 PM. Our storm and cold front marches toward us from somewhere over the horizon, though visually you’d never know it. Wonder if the native Americans knew this odd sequence–probably.
The weather ahead
After the last drops fall today, we’ll suffer through another dry spell and warm up though about the 20th when a major trough passes by.
The End
Oops…. Have cameras ready for a great day of cloud shots once the sun breaks through.
Doesn’t happen every November, thunder, but it sure pounded away at times yesterday. Seemed louder than usual thunder a few times even with the lightning over there by the Tortolita Mountains. Of course, that’s where the heaviest rain fell as several T-storms tracked along a similar path over there just a little to the W through N of us, Bio2, in one of the heavier cloberations receiving 1.17 inches.
Here, in The Heights, we received a disappointing, but nevertheless welcomed final total of 0.24 inches. This brings our total here in Sutherland Heights for November up to 0.60 inches. Average is 0.96 inches1. Here, the regional totals as the storm was coming to an end:
“Us” is here in the Sutherland Heights; “Them” is Bio2. Wanted to reflect the general world situation now days by using oft used cliché terms.
As is proper, let us begin examining the nubilations of our storm by looking at those clouds that preceded the actual rain day yesterday.
7:02 AM. This pretty sunrise over the Catalina features a couple of flakes of Altocumulus clouds, and a vast layer of Altostratus.7:04 AM. Yes, the sun is coming up, though really its the earth rotating toward the sun. The sun does not go around the earth every day; it only SEEMS that way. We’re looking at the same two cloud generas, btw. Nice rays produced by pretty regular humps in clouds over the horizon, a little row of Altocumulus castellanus might cause these rays/shadows.7:05 AM. This was pretty interesting, to use “pretty” again. This would be an Altostratus mammatus. Men often find this formation especially interesting and pretty. Here you can also see how a cloud protuberance can produce a shadow. But why is there only one feature like this? Typically mammatus are like upside down Cumulus turrets representing downward moving cloudy, in this case, air filled with ice crystals). Adjacent to this feature, the ice crystals and snowflakes are just settling out. As the moving downward air in mammatus features slows, these breast-like globules open up and you’ll have ordinary virga. The ice crystals are typically rather small and not rimed (that is, have not collided with cloud droplets) or they would fall out and not be constrained to this pretty, rounded shape.7:07 AM. The underside of the Altostratus is lit up, showing the detailed areas of virga. Altostratus, by definition, is a precipitating cloud. Its just that the bases are too high for the precip (snow) to get to the ground, though sprinkles could occur in the thicker, deeper versions. When and if it starts to rain steadily, the cloud is better termed a “Nimbostratus,”11:20 AM. The Altostratus deck departed with its pretty mammatus and virga, leaving great examples of Altocumulus opacus clouds most of the morning and into the early afternoon.3:24 PM. An example of Altostratus translucidues doesn’t get better than this. Hope you captured it. The As (abbrev. for “Altostratus”) cloud over took over by mid-afternoon as the moist layer deepened again following the Altocu. Tops of this all ice Altostratus layer, in spite of being able to make out (“discern,” not “make out” in the social sense of the phrase–still thinking about that mammatus formation) the sun’s position, are usually around Cirrus levels, the top of the troposphere. The TUS sounding suggested “bases” (actually where the ice crystals are evaporating rather than droplets that comprise the bases of Cumulus, Altocumulus or other droplet clouds) at 14,000 feet ASL, and tops around 34,000 feet ASL Subtract about 3 kft to get heights above the ground here in Catalina.
Moving ahead to yesterday…..
7:13 AM. With an approaching upper level trough and big low center in the Great Basin, the winds had become gusty, and the clouds had lowered to Stratocumulus status, topping the Catalinas. I thought the lighting was really pretty here, and that shaft out there shows that turrets are climbing shooting up well beyond the general tops of the shallow Stratocu. Pretty exciting since it meant that the tops of other Stratocu might bunch into other Cumulonimbus clouds, which is what that shaft tells you.8:18 AM. A line of Cumulonimbus quickly erupted and it looked like it was about to crash into the Oro Valley Catalina area, but instead stayed to the west over the Tortolitas. Thunder heard!8:19 AM. Looking WNW toward the Tortolitas.9:27 AM. As some light showers passed along the Catalinas, this pretty scene the sun broke through. Note the glistening rocks that added such pretty highlights.9:28 AM. Pretty nice over toward the Gap, too! I will never get tired of these scenes!11:12 AM. Disappointingly, in view of all the rain predicted here (0.575 inches) that first line of Cumulonimbus clouds stayed stayed west of Catalina. But, that line of Cumulus or Stratocumulus clouds on the horizon is full of stormy portent, that a windshift line might be about to strike and generate another line of Cumulonimbus clouds. Any solid line of clouds like that, kind of by itself, suggests a windshift; it more than just a fair weather “cloud street.”11:11 AM. Zooming in on that line of clouds. Its fun to zoom, since you are in a way, flying toward what you’re looking at, getting so much closer! I wish that line of clouds was here already!
11:27 AM. Yep, there it goes, fattening upward into Cumulus congestus and to the N, Cumulonimbus clouds! This one will surely blast across Catalina as the upper trough and associated cold front approach; heck, maybe that’s the cold front windshift line and temprature drop right there!11:27 AM. Yep, there it goes, fattening upward into Cumulus congestus and to the N, Cumulonimbus clouds! This one will surely blast across Catalina as the upper trough and associated cold front approach; heck, maybe that’s the cold front windshift line and temprature drop right there! Repeated for emphasis.11:29 AM. A Cumulonimbus cloud is a bit farther north in this line. This HAS to be the windshift and cold front!11:46 AM. Was inside for a few minutes (18) and that cloud line just exploded over there. Here looking again toward the Tortolitas. But surely they will wall out and crash the sunny party in Oro Valley (I was thinking).11:52 AM. Well, these followup Cumulonimbus clouds aren’t looking so great, no evidence of strong turreting, weak and leaning, wispy, frail, “indolent”, cloud “couch potatoes.” Hope fading for a big shafting here in The Heights12:12 PM. The cloud line, as expected is progressing across Oro Valley, but shafting is meager. Its real windy, though, adding some drama. Gusts to 40 mph! Note however the weak shafting, as evidenced by a slope across the whole thing; no heavy, large particles falling out of this guy as we see in those vertical summer shafts. Indicates that the tops are getting very high, producing lots of condensate. So even here, with a nice dramatic scene, you’re thinking (to put words in your brain) that its going to be a disappointment in rain production, and you might be missed altogether!12:24 PM. It was pretty much all over 12 min later, that is, the chances for a real shafting. A well formed Cumulus congestus base formed just upwind of Catalina, but as so many do, slipped a little east before reaching Cumulonimbus stage and unloaded on the Catalina foothills NE of Catalina. Sometime, when clouds like this are overhead and show no precip, it just can dump out of the black. But, it didn’t happen yesterday. By now, the wind had shifted, the temperature was falling, and soon, the light to briefly moderate rain fell as the cold front went by.1:14 PM. By this time, you could pick up a couple of nice photos of just Stratocumulus clouds following the passage of the front. Here we see some indications of mammatus formations (upper center, right) in a droplet cloud, an extremely rare event since droplets evaporate so much faster in downward moving air that the pouches represent. One can surmise that those pouches may have contained higher amounts of liquid water, and the downdrafts were very slight. OK, so we’re kind of fixated on mammatus today…. No apologies; I’m just a man.
The great thing about yesterday was that because the upper trough lagged so much behind the cold front, you could be sure it wasn’t over, that is, the rain chances. In fact, as the wind turns aloft from a southerly or southwesterly direction to a more westerly one, we here in Catalina have a better chance of having the clouds pile up over us, even if they’re not full fledged Cumulonimbus clouds, they can still reach depths where they precipitate while upwind, they don’t because they may not be deep enough. The Catalina Mountains provides the lift that helps do this, and we saw that happen later in the afternoon and evening when it began to rain again long after the cold front and it so-so rain band went by.
3:06 PM. Starting to look more favorable for rain and the clouds began to cluster after the boring spell of Stratocumulus except for the brief display of pretty mammatus. The air aloft was getting a little colder, too, helping the Cumulus clouds deepen upward in spite of cool temperatures following the front. This view is looking upwind to pal Mark Albright’s house there in Continental Ranch, Marana. Mark is a fellow U of WA research meteorologist, though he hasn’t thrown in the towel yet, is still working.3:34 PM. Even as the clouds filled in and the light showers began, some pretty highlights were observed where the sun peaked through holes in the overcast. Here, Eagle Crest to the north of The Heights is spotlighted. If you are a resident of Eagle Crest and you would like a copy of this photo entitled, “Spotlight on Eagle Crest”, you can get one today for $1200, If you call now, you can get two for $2400.5:25 PM. FInally, as the light rain fell, adding a few more hundredths to our total, sunset occurred! You can see it WAS raining by the drop on the camera lens, I didn’t just say it was raining because I wanted it to. Note the lack of shafts. This tells you the tops of the clouds are pretty uniform, not protruding much above us. The rain was “pretty” steady, another indication that the clouds are relatively uniform in the horizontal.
The End, FINALLY!
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1If we don’t get more rain by the end of November, I will delete the sentence of a week or so ago stating that November would have above average rainfall. No use having people see that.
We’ve waited a LONG time for a rain day. It was so nice, so photogenic as well. I hope you enjoyed it as much as I did.
Also, you may have seen the Froude Number1 in action as Cumulus congestus and Cumulonimbus clouds developed and went around the sides of the Catalina Mountains instead of developing over them and dumping big shafts of rain on them. The heaviest rains yesterday were due to streamers of showers and with an OCNL TSTMS that were north and south of us, Oracleville, Bio2 area, and Marana, Avra Valley where over half an inch was logged in some places.
Still , we managed a third of an inch here in Sutherland Heights, the first appreciable rain since I don’t know when, though, I could look it up. Too long, though, even for Catalina.
Some regional totals, 3 AM to 3 AM: Precipitation Report for the following time periods ending at: 03:19:00 11/04/16 Data is preliminary and unedited. —- indicates missing data Gauge 24 Name Location ID# minutes hour hours hours hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.08 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.12 Oracle Ranger Stati approximately 0.5 mi SW of Oracle 1040 0.08 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.16 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.16 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 0.24 Cargodera Canyon NE corner of Catalina State Park 1080 0.20 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke 1100 0.16 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains 1030 0.04 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak 1090 0.16 Mt. Lemmon Mount Lemmon 1110 0.16 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp 1130 0.28 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.08 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.16 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station 2280 0.04 Green Mountain Green Mountain 2290 0.16 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Santa Catalina Foothills 2090 0.04 TV @ Guest Ranch Tanque Verde Wash at Tanque Verde Guest Ranch 2100 0.16 DEQ Swan Swan Rd at Calle del Pantera 2160 0.08 Sabino @ USFS Dam Sabino Creek at USFS Dam 2170 0.24 Ventana @ Sunrise Ventana Canyon Wash at Sunrise Rd 2190 0.16 Al-Marah near El Marah on Bear Canyon Rd 2200 0.04 AC Wash @ TV Bridge Agua Caliente Wash at Tanque Verde Rd 2210 0.00 Catalina Boosters Houghton Road 0.1 mi S of Catalina Highway 2220 0.04 Agua Caliente Park Agua Caliente Park 2230 0.04 El Camino Rinconado El Camino Rinconado 0.5 mi N of Reddington Rd 2240 0.04 Molino Canyon Mt Lemmon Highway near Mile Post 3 2390 0.24 Finger Rock @ Skyli Finger Rock Wash at Sunrise Rd
Yesterday’s Clouds
6:50 AM. “Shape of things to come1.” “Nothing could change the Cumulus shapes of things to come” yesterday, to paraphrase here, as evident in this Cumulus shedding ice in the downwind decaying end on the left.7:35 AM. Look at this little guy, so full of ice. Another harbinger of the ice-filled clouds about to arise, and with ice, precipitation, snow aloft, graupel (tiny soft snowballs), and even some hail (solid ice). You could guess here from how shallow this Cumulus cloud is that the bases must be at near the freezing level, and tops must be at least as cold as -10° to -15° C, cold for such a small cloud. But what would we call such a small cloud? Cumulus congestus praecipitatio or virgae (since the present of ice absolutely means some precip up there, not likely reaching the ground though. Shoot from the hip estimated depth 2 km, or around six thousand feet.11:37 AM. Sure enough, as it got warmer, Cumulus congestus/small Cumulonimbus clouds arose trailing ice northwestward in huge plumes of ice. Note to airborne researchers: be sure to sample the older parts of the turrets that have trailed downwind and turned completely to ice even though that trailing portion doesn’t look much like a Cumulus cloud. It you only sample the newly risen portions, you will cheat the cloud out of how much ice it can produce since it takes a little time for all the ice to form. Lotta early airborne researchers made this error, reporting too little ice, but, of course, if they were in the cloud seeding business, they wouldn’t mind at all since they could report that clouds needed more ice, that from their seeding activities!11:37 AM. Oh, so pretty, those dark blue skies punctuated by a little muffin Cumulus cloud. Aren’t you glad you live here?1:25 PM. Showers and weak Cumulonimbus clouds trail off the Catalinas north of Bio2.1:25 PM. In the meantime, stronger Cumulonimbus clouds and showers track westward south of Catalina toward Avra Valley while the clouds over the Catalinas dissipate or remain disorganized while heading toward us.2:33 PM. A voluptous Cumulus congestus in the process of transitioning to a Cumulonimbus calvus (ice is visible but top stil pretty firm and round looking), then Cumulonimbus capillatus (fibrous top) AN older turret, looking all ice, leans to the left. Precip was already dropping out the bottom of this fat cloud. What kind would it be? Grauple, without doubt since so much supercooled liquid water would remain in this cloud amid the ice crystals forming inside. Those ice crystals, nice and pristine when they first form, would have their pretty forms obliterated by droplets that would freeze instantly on them, making them little snowballs, falling faster and faster, collecting more droplets.2:46 PM. Moving rapidly away from Catalina, of course, that cloud has now become a Cumulonimbus capillatus (hairy, fibrous top a,most completely composed of ice–some liquid may still arrive at cloud top in new turrets before quickly converting to ice.) A portion of a rainbow can be seen at almost ground level.2:48 PM. In the meantime, pretty strong storms, now having thunder, rage S through W of Catalina.3:14 PM. While we didn’t have any great clouds near us, at least we had some nice lighting (not LTG) on the mountains from time to time.3:41 PM. Finally, the dramatic skies were shifting northward and measurable rain was on the doorstep. Looking SW toward Pusch Ridge and the Tucson Mountains.4:43 PM. Took awhile, but a decent Cumulus with a nice base now transitioning into a Cumulonimbus plopped some big drops and hail down. Streak at right is a hail particle with its fall distance in about 1/400 of a second.4:47 PM. The hail got a little bigger and I took a picture of one of the stones, a little smaller than pea-sized in case you don’t believe me that some hail fell, too. Sometimes I think people don’t believe what I write, especially in footnotes….5:02 PM. While the sunset was dramatic, it didn’t bring the color hoped for, but this line of dark clouds presaged another bit of rain for Catalina.
Except for a morning or afternoon sprinkle, no rain in sight, just a warm up back to above average temperatures. Dang.
The End
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1The young fluid dynamicist, Richard Penniman, fascinated by the flow around mountains, and who later became known as the rock and R&B entertainer, “Little Richard”, first brought the Froude Number to public attention in his song, “Tutti Froude-e.” The title, after an early release failed to capture the public’s imagination, was later revised for greater “accessibility”, to the song we know today as, “Tutti Frutti.”
2Who can forget “Max and the Storm Troopers” and that great song? I would submit, “everyone.” Of course, few know that after 1968 they changed their name to “Led Zeppelin.” And that, my friends, is “the rest of the story”, as Paul Harvey might say if he was lying about something anyway.
The day started with some nice Altocumulus “pancakus”, some lenticulars and breezy conditions, reminding one of fall day with a cold front approaching. Small Cumulus appeared quickly, but with the wind, you wondered if they would get enough heating to power upward into Cumulonimbus clouds.
By noon you had your answer as a large Cumulonimbus complex settled in just beyond the Tortolita Mountains west of Catalina. And it pretty much recurred there and over the Tortolitas all afternoon. In the meantime, passing light showers dotted this side of the Catalinas, but that was about it. No “Code 4” shafts on those mountains yesterday. Rain totals were less than a half inch, and most less than a third. On the other hand, would guess that parts of the Torts got well over an inch. The cores missed us again, with Sutherland Heights logging only 0.03 inches.
Developing showers passed over Catalina dropping occasional very large, sparse drops, but shafts generally fell out of those clouds after they had passed off to the northeast.
Late in the afternoon, the line of recurring showers finally approached Catalina, but as dry air encroached in the middle levels, at the same time, catching up to that standing line, all those great mushrooming clouds were no more. The cloud story board is below:
(by Chad and Jeremy but with photos of Peter and Gordon with whom the former were often confused with, the site notes! How funny is that?)
Oh, well, yesterday might well have been the end of the summer rain season here in Catalina as far as rain goes, so an ending point song seemed appropriate.
6:16 AM. Altocumulus with a underlying Altocumulus castellanus.6:16 AM. Another view of Altocumulus with an underlying line of Altocumulus castellanus.8:06 AM. Altocumulus perlucidus translucidus (real thin).10:55 AM. Altocumulus lenticularis clouds provide the real look of a fall day with a significant jet stream overhead. Cumulus begin to form on the Tucson Mountains in the distance.12:56 PM. The idea of a fall day is quickly dispelled by the rapid growth of a narrow Cumulonimbus calvus cloud.12:57 PM. Wow. At the same time, there’s been an explosion of Cumulonimbus clouds to the west through northwest of Catalina. This looked REALLY promising for a dump here, since it would surely expand southward (to the left) from the rain shafts in progress.1:30 PM. Line of thunderstorms reaches the Tortolita Mountains. This is looking extremely good for Catalina though the thunderstorm is moving left to right rapidly, not toward us. Why does it look good for Catalina? Because you expect winds pushed away by all that falling rain to blow back against the sotuhwest winds and generate new Cu congestus and Cumulonimbus clouds upwind of the shafts, and more in line with Catalina. Summary: it didn’t happen though there were numerous times it looked like it was verging on doing this. So, all those thoughts you had out there that this was going to happen were in considerable error. This was probably because the southwest wind against which the outflow was clashing, was too strong yesterday, limiting how far upwind new clouds could develop.1:34 PM. This was looking so great! Bases massing there on the right side, pretty much upwind of Catalina.1:43 PM. Tortalitas now obscured by water.1:49 PM. Showers are developing farther upwind of the main blast over the Tortolitas as expected and near to upstream of Catalina! Gloating here. Was SURE now we’d get a tankful of rain within the hour.1:53 PM. In only a few minutes its looking so much better for us, and those showers and thunderstorms are racing this way! Looks like the whole line is drifting east, too. In the meantime, the thunderstorms moving away from the Tortolitas and toward Saddlebrooke Ranch and points north have sent out a blast of northerly winds into Sutherland Heights, pretty much like yesterday. The clouds overhead begin to respond to that uplift caused by this blast of north winds.2:06 PM.2:16 PM. That first nice cloud base waited until passing by to drop its load, but another promising one appeared upwind!2:17 PM. In the meantime, another ferocious thunderstorm is dumping on the same area of the Tortolitas as the prior ones!2:21 PM. A closer look at the Tortolita blast. Expect wind from this to reach Catalina.2:22 PM. WIth the north wind blowing you’re looking for something to erupt upwind of us as the nose of that north wind pushes into Oro Valley. But here you see that the organization of the cloud bases is poor, too many little light and dark areas, no broad base indicating a strong updraft. This was a depressing shot but I took it anyway.2:27 PM, The severe thunderstorm over the Tortalitas has moved NE. Here you see the kind of cloud base you want to see just upwind of you, not that mess in the previous photo.2:29 PM. Only a few minutes later, but look at the change that has occurred upwind of us! That north wind scooting down into Oro Valley has finally triggered a massive base just upwind of us We are going to get pounded!2:33 PM. But that great cloud base moves to the west of us, adajacent to yet another blast on the Torts. Ugh. Just can’t get this right.2:36 PM. Some lightning for you in case you don’t believe me that these were thunderstorms.2:49 PM. Yet another promising base, more in the upwind direction passed over, only to leave some enormous drops. Compare splash marks to that mesquite pod on the sidewalk. Sounded like hail at first. But the main load fell downwind. I thought we were going to really get shafted right then, too. Not.3:03 PM. An example of poor cloud base structure upwind of us.3:04 PM. Curtains of heavy showers continue to bombard the Tortolitas, Amazing how many cells passed through that area as this zone of converging winds remained stationary instead of advancing toward us as I believed it would.3:18 PM. As skies cleared overhead, some of the prettiest scenes of the day were of these brilliantly white Cumulus congestus clouds over the Catalinas.3:20 PM. Ice detection drill… Can you tell that those two turrets in the last photos are now mostly ice?3:28 PM. Can a scene be more beautiful? The turret on the far left has converted to ice.3:29 PM. A single strand of hail or the largest drops have plummeted out of this base. This suggests that they were either very large particles, or that the updraft had a minute weakness that allowed some of the load aloft to escape in something of a narrow chute. And, of course, its part of the line still pounding the Tortolitas!3:47 PM. FINALLY the line appears to be shifting east toward Catalina, but the tops aren’t as high, there are no giant cells any more, an indicating that both drier air is moving in and that the instability aloft is changing to less favorable for large storms. Oh, me. This was a discouraging scene.3:55 PM. While not as heavy as prior showers, there is still hope that the line will produce measurable rain in Catalina as it drifts east.4:05 PM. By this time, its looking like the slowly advancing line will die before it gets here.5:24 PM. That line: Done and done.6:39 PM.
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.
Yesterday’s clouds
1:30 PM. Yawn. Its 103 F, dewpoint 60 F. Baby Cu begin dotting the Catalina Mountains.2:14 PM. Cumulus congestus finally arises within the local cloudscape. Looks like the top is high enough to convert to ice.
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.
2:19 PM. The declining right side of this cloud has ice in it, but its hard to detect for most observers. Only the BEST of the cloud-mavens could scream out, “there it is!”, before its more obvious to the less gifted CMJPs.2:22 PM. Well, too easy now to see that there’s ice in those little fingers extruding out from the body of the cloud; evaporation of the cloud drops has left the slower evaporating ice “naked” so-to-speak. It also in the higher turret, and would be termed a “calvus” topped Cu, properly, Cumulonimbus calvus, though not much fell out of this one, close to Saddlebrooke.3:31 PM. In the meantime while I wasn’t looking, Mt. Lemmon erupted sending a plume of cloud droplets, higher up, ice, skyward to at least 35,000 feet ASL. Indicated a phenomenal amount of instability afternoon, instability that was about to be realized in a line of mammoth Cumulonimbi.3:49 PM. “Eruption” just about over. Notice how skinny the root is now, AND that the top of the stem of convection is now only about half as high as in the first shot. Like a wild fire plume that has cooled off, the plume height goes down. Still formed ice on the right side, as you SHOULD be able to see. You should also be guessing that those were likely warmer habit crystals, like needles and sheaths. I did, if that’s any help.4:38 PM. Another cloud jack (Cumulonimbus eruption indicating a whole lotta instability), tops probably far above 40,000 feet. A lower portin of the anvil drifts southward toward Catalina. This one was dumping somewhere near the Biosphere 2 landmark. Note that anvil, lower right. That was our incoming major complex of Cum5:17 PM. WOW! This was magnificent, and just one of the many large Cumulonimbus clouds racing toward the Catalina Mountains. This is the one that in the video, the crown of it can be seen forcing the air over us in the opposite direction. Still, it was not certain at this time these storms would make it here. And, this is looking ESE, while the storm movement was from the ENE.5:25 PM. The “Menace of Charouleau Gap”. Many of our worst storms roll in from the ENE, toward Charouleau Gap, and many who have lived here will tell you and this is the archetypical seen for those storms. A sudden blackening of the sky beyond Charouleau Gap. These darker clouds are rarely the ons producing the storms, but are riding a strong NE wind surging toward Catalina, about to produce some mayhem. The winds always arrive before the rain. And, as a few days ago, there are times when ONLY the wind arrives, there is not enough instability aloft to allow the storms to drift past higher terrain without falling apart. On this day, they will make it.5:48 PM. I am going to work this scene over because it is associated with one of the more spectacular storm sequences here in Catalina, one that comes up usually a few times every summer. The anvil outflow aloft is thickening and lowering, and the outrider shallow Stratocumulus are racing out and along the Catalina Mountains. Things are changing incredibly fast and the NE wind is about to hit.6:05 PM. Walking the dogs to beat the rain, The NE wind has hit, the power line wires are howling. The sky continues to darken and look ominous, but….no rain shafts have come over the mountains, a cause for concern.6:21 PM. The shallow clouds ahead of the rain area continue to spread down and out from the Catalinas. A small opening in the clouds allows this dramatic highlight. I like highlights.6:22 PM. Let’s look a little closer at this spectacular highlight. Wow! This is just as good as a bolt of lightning.6:33 PM. Maybe time to get the Good Book out, cram for the finals…. This was really quite the sight, considering it had been so sunny just a couple of hours before. Again, these are fairly shallow clouds riding the outflow winds, now gusting 35-45 mph in Sutherland Heights. The mottled bases here indicate that there is no organized wide updraft to launch them into deep Cumulonimbus clouds at this moment, anyway.6:34 PM. Finally, a major new rain shaft emerges over Samaniego Ridge, upstream of Catalina!6:35 PM. Looks like more and more people are dropping off Word Press as these files are going in pretty easy now.Here, the apocalyptic cloud formation rolls down and out across Oro Valley, with heavy rain just to the left.6:43 PM. A rare sight, wind driven rain streaming off the tops of the foothills of the Catalinas. The winds were likely hurricane force (>64 knots, 74 mph) to do this. Samaniego Peak received 1.50 inches during this storm.7:21 PM. Sunset in Catalina, July 29th. The sun does not have a sharp disk, is rather blurry, because the light from the sun is being scattered by large particles like rain drops which bend the light so that we can’t see the disk’s outline. When its smog, the particles are of the order of micrometers and a sharp disk will be seen because the sunlight is not bent around large particles. I think Einstein said that…7:21 PM. Orange and rainy as sunset procedes as usual.
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)
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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.
Back to weather and yesterday’s microburst with three minutes of sheets of unbelievably heavy rain with rice-sized hail, 50-60 mph gusts, blazed across Sutherland Heights between 4:06 PM and 4:13 PM. It was a memorably violent storm, comparable in those worst 2 minutes or so to anything we see in the summer, and it was completely un-predicted for Catalina the day before (0% chance of rain here) though showers WERE predicted for the higher terrain of eastern AZ yesterday). For the full story, see Bob M’s excellent discussion. For just clouds and stuff, here is OK.
Looks like the Sutherland Heights got the most of anyone anywhere near here. No reporting station in the Pima County ALERT system in Catalina or in the Catalina Mountains got measurable rain, that’s how local our storm was. Rarely if ever do you see that happen.
Stuff blew everywhere and I felt lucky not to lose some branches of trees in the yard. Here’s yesterday’s cloud diary. First the background about what was happening, the TUS balloon sounding of the atmosphere:
The TUS sounding at 5 PM AST (launched around 3:30 PM). Classic inverted sounding associated with downbursts. Cloud bases are at 0 °C (32 °F) at 14 kft above sea level, or about 11,000 feet above us in Catalinaland. Lots of turning of the wind, too, helpful for stronger storms. So, rain and hail had a long ways to fall, cool the air, drag it down and blast the surface.9:43 AM. Castellanus of the morning. Patch Cirrus on top. Recall that in my cloud chart it says when you see this cloud, it might rain within 6 to 196 h. Pretty accurate yesterday since it rained about 7 h later here.2:11 PM. Cumulus were reaching mediocris stage around here while off to the horizon, Cumulonimbus tops could be seen over the higher terrain of the Mogollon Rim.2:11 PM. However, a single Cumulus congestus just past the Tortolita Mountains was transitioning into a little Cumulonimbus. Precip is fall out of that lofted flat side of the cloud to the left of the main base. What a surprise to see that! But it was clearly too small to do anything.
3:00 PM. However, those cloud over there kept shooting up turrets, becoming larger and larger until we had us a full blowed Cumulonimbus and something in the way of a rain shaft (Code 2, transparent, except for that one strand–almost certainly a hail or graupel shaft).3:54 PM. While CMP had to be inside for an hour, this surprise happened just to our SW, with rain falling on this side of Pusch Ridge! Wow, WHAT an interesting day this is turning out to be! Not only was there rain, but thunder! Didn’t think it would get here, well, maybe a sprinkle is all.4:02 PM. The rain shaft had gotten denser, and there are tendrils of heavier precip. Thunder is a remarkable every minute. Didn’t look vigorous enough for that kind of electrication rate. What’s really promising now is that darker round blob in the upper right hand corner of the photo indicating new cloud growth. That raining part of the cloud would hardly make it here even if it came right at us, given the light winds up there; needs to be replaced by new cloud growth. Was thinking now, “Gee, it might measure!” No thought of wind yet since that shaft looked kind of weak..4:04 PM.4:04 PM. Looked down on Catalina to see this remarkable site, a surface dust plume racing through town, rain just behind it! At this point you could see that it was going to blast the Sutherland Heights, so was a pretty exciting moment, and the rain was certainly going to be measurable if the gauge didn’t blow over!4:04 PM. Another view of this shaft just before the wind came roaring over the hill in the foreground. From the incredible but very short-lived torrential rain, Sutherland Heights must have gotten one of those narrow strands, but again it would not be one of those you see there, but something dropping out almost on top of us.4:06 PM. Here it comes, just over the hill. You can see the surface dust plume advancing north into Catalina where no rain fell!4:06 PM. Here’s something you rarely see, dust blowing off the little hills above the Sutherland Wash, Baby Jesus Trail area. Rain was just starting here.4:09 PM. Just about the peak of the rain shaft. Horsey retiree Jake shows that the wind si blowing away from the corral. The visibility is relatively high in this extremely heavy rain because the shaft was so tiny.4:09 PM. Just seconds later the shaft had moved a few blocks away and down the hill (whitish area running from left to right). Note expanse of blue sky in the background, too.4:13 PM. Storm is virtually over and here you can see the amount of water that came of the roof, and some wind damage (cushion out of place). Some cushions went down the hill.4:43 PM. The day ended peacefully enough with more Cumulus and distant Cumulonimbus clouds around. Great sunset scene of clouds over the Catalinas, but was enjoying live classic rock music at a friend’s house with some 50 others; no camera.
Too dry today for rain. Next chance for rain around the 17-19th as that bigger (but maybe drier) cold trough settles in. Temps will be nice, though. Lots of intermittent trough action indicated in 06 Z mod run through the rest of May, so May should continue to be pretty interesting and likely devoid of never-ending heat month as sometimes happens here. This scenario pretty well supported in those crazy NOAA spaghetti (or Lorenz) plots.
The End
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Photos not loading in WordPress now, so quiting here, dammitall! Must go on to other chores now. Not happy!
OK, photos finally went in. Happy now, though too many photos as usual.
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1I doubt that happened…. Really, this was a song about people who don’t like to go to work, kind of anti-capitalist which is ironic because it was that system that allowed the boys to make their millions (billions if they had invested wisely into Microsoft in the early 1980s) and gone on to help the world with their billions like Bill and Melinda.
Truly LATE breaking news, untimely really, but Augustober 18th was too special a day to ignore:
Giant clouds, dense rain shafts, frequent lightning in the area throughout the afternoon, dewpoints in the high 50s to 60 F; can it really be after the middle of October? Or, is this some kind of preview of climate change we can look forward to in the decades ahead, that is, if you’re thunderphilic?
5:05 PM. An amazing scene, and thunderstorm with such powerful updrafts that when those updrafts are blocked by the inversion at the base of the Stratosphere, they force the winds at that level to slow or backup and the anvil protrudes upwind (center left), something that is common with severe thunderstorms. This was significant here because the winds at 40,000 feet were around 50 kts, far stronger than anything we have here during a typical summer rain season. Summer Cumulonimbus cloud anvils can splash outward easily against weak winds up there in summer when they hit that barrier at the top of the tropopause. This just in from Mark A: severe thunderstorms, I have just learned here on the 20th , were observed in the PHX, and the NWS has a great link going describing all the mayhem it produced. I did not know this until just now in the middle of writing this first caption when I read Mark’s e-mail.1:40 PM.
1:56 PM. Anvil of the Cumulonimbus over west Tucson, drifts overhead of Catalina, and in three minutes, rain drops started to hit the ground. This is amazing because those drops had to fall from at around 20, 000 feet above the ground (estimated as bottom height of this thick anvil) and could only have happened if those isolated drops had been hailstones ejected out the anvil, something that also only occurs with severe storms with very strong updrafts in them. So, if you saw those few drops fall between 2 and 2:05 PM you saw something pretty special.
6:26 AM. Early portent: Cu congestus, aka, “heavy Cumulus) piling up this early.6:29 AM. Mammatus of the morning., an extraordinary scene for mid-October, pointing to the possibility of an unusual day ahead with strong storms. as was the scientific basis for giant clouds on the 18th in the amount of CAPE predicted, over 1,000 units of Convective Available Potential Energy, later that day from computer models. That is a lot for mid-October, take my word for it.3:45 PM. Strong storms did not form over or near the Catalinas yesterday, but they did get something. As you can see the top of this guy (Cumulonimbus calvus) is very subdued compared to the giants that formed elsewhere.5:53 PM. Peakaboo Cumulonimbus calvus top east of Mt. Lemmon provided a nice highlight after sunset. And to have convection like this going on this late was remarkable. Some heavy showers and a thunderstorm formed downwind of the Catalinas about this time,, too.5:51 PM. Pretty nice, summer-looking sunset that day, too.
The weather just ahead, and this might be it for precip for the rest of October
A nice-looking upper level trough is ejecting over us from the SW this morning but the computer model says its going to be a dry event. A second low center forms just about over us in the next day. AZ model doesn’t see much rain for us throughout these events, and rain doesn’t begin here until after dark today.
I think that is WRONG; bad model. Watch for some light showers this morning, then a break and rain overnight (which the models do predict). Due this quite bad model forecast, as seen from this keyboard, I feel must interject for the blog reader I have, an improved rain prediction for Catalina over that rendered by a computer model.
Feel like guesstimating a minimum of 0.25 inches between now and Thursday evening, max possible, 0.60 inches, so the median of those two, and maybe the best guestimate being the average of those two, or 0.425 inches here in Catalina. When you see a prediction of a rainfall total down to thousandths of an inch, you really know that the person predicting it knows what he is doing…..
Below, your U of AZ disappointing, but objective, take on the amount of rain based on last evening’s data and one that is the result of billions of calculations. One must remember that cloud maven person’s calculation of the rainfall amount for Catalina is only based on three.
From the 5 PM AST run executed by the U of AZ Beowulf Cluster.
Morning thunder, evening thunder; 0.84 inches of rain, 1-2 inches in the mountains, with some of the most dramatic skies and shocking cloud changes ever seen (by me). “But, hey, enough of ‘me’, lets get on with the ‘shockumentary'”, as Rob Reiner might say.
Scene 1: Its morning. A horsey ride has been planned with an important, published friend. You’re thinking, “It will be good to be seen with someone important.” No one’s paying attention to weather. The weather is cloudy, quite nice really, but nothing threatening can be seen.
6:48 AM. Nothing to worry about really. Just a patch of Altocumulus castellanus. Quite pretty.
Scene 2. Heading out.
7:20 AM. Wonder what that is coming ’round the mountain. Probably nothing, though it is kind of dark over there. Cloud bases are lower, too. Desert’s turning a nice green now after the recent rains. Too bad there isn’t more rain ahead.
Scene 3. On the trails.
7:33 AM. Been on the trails for quite awhile, maybe more than 12 minutes… Cloud bases lower still, but, its probably just harmless, non-precipitating Stratocumulus. Nothing to be too concerned about, though the amount of water in the air must be prodigious today.
Scene 4. Ooops
7:43 AM. Rain and thunder approached rapidly. Note horse’s rear pointing in the direction of the storm (lower center right). As a horseman, you would know that horses often point there rear ends at storms, hard to say why, but its a classic sign that a storm is approaching from that direction, though you can see it yourself as well. Actually, we were fleeing like mad, embarrassed galore that cloud maven person did not look at radar that morning to see what was over the hill.
Scene 5. Dramatic skies and a few close strikes.
7:47 AM. Just about back, but LTG strikes getting closer faster.
The storm passed dropping 0.22 inches. And, compounding error, as we know, when potent upper air disturbances bring morning thunder and rain, its pretty much always the case that the rest of the day will be dry as a subsiding couplet of air follows a rising one, the the strongly rising couplet of air that forced our morning clouds and storm.
So, was kind of looking ahead to a disappointing rest of the day , but was thankful for the unusual morning storm.
1:49 PM. As expected, a large clearing occurred following the morning rain, and a few harmless Cumulus developed over the Catalinas.5:49 PM. A thunderstorm passes NE of Catalina, but like the day before, will likely only bring on “a mighty wind”, to quote Rob Reiner again, though a rain-cooled one. That will be nice.5:59 PM. Quite “histrionic”, but certainly won’t get here…..6:07 PM. Nice Cumulus congestus in foreground; giant anvil in back from the storm to the N-NE.6:10 PM. Nice scruff of Stratocumulus/Cumulus mediocris rides above the NE winds that blew out of the storm to the north. Certainly, these clouds won’t do anything. Bases disorganized, nothing congealing.6:17 PM. Huh. Bases looking a little better, especially back there over the mountains. Still, seems VERY unlikely anything will happen. Its late in the day, temperature falling…..6:31 PM. The larger base has crept closer to Catalina. But, as you can plainly see, its not doing anything, and hasn’t over the past 20 min or so, so you can pretty well forget that it will do anything. A few minutes later, thunder began to erupt from it. I could NOT believe it, as you were thinking as well. No sign of an anvil, ice, or shaft! Forecast of no rain going bad….very bad.6:34 PM. There it is, on the right, the emergence of the shaft from one of the smallest thundering clouds this writer has ever seen. Within a couple of minutes, Oro Valley below was not visible!6:40 PM. Looking at Oro Valley!6:41 PM. Looking toward Catalina, lower portion. Its gone. The visible sun shows that the intense rainshaft and cloud cover were quite narrow and limited.6:54 PM. Backside of first dump shown above. Magnificent!
But it wasn’t over by a long ways was it?
6:53 PM. A new, much larger, firmer base has formed in the same spot as the previous storm. And you KNOW its going to dump on us!7:01 PM. What a blast! This one brought pea-sized hail to the Sutherland Heights neighborhood.7:02 PM. Perhaps the shot of the day of the first evening blast as it moved over and past Saddlebrook.
You won’t have to go to New Mexico, Sonora, or the Indian State of Kerala to find great summer rain. According to this model output from last evening, its only a bit more than a week away!
The last time we saw a model prediction like the ones below, was for the 24 h ending today, made a whopping 12 days ago. When you consider the great rains we had ending YESTERDAY morning (2-7 inches in the mountains, and inch here in The Heights, that far out prediction was only a day or so off. So, there’s hope that the paucity of summer rain that has left our desert so brown will be rectified a bit more in the near future.
Below, from 5 PM AST obs, the WRF-GFS 12-h rain totals predicted for August 20 and beyond as rendered by IPS MeteoStar. Normally, these are pretty useless predictions, but since that last one with so much rain foretold was close to what actually happened, maybe there’s something to watch out for around the 20th.
Valid at 5 AM AST, August 20th. Colored regions denote areas where the model has calculated that rain has fallen during the prior 12 h. Blue indicates heavier precip than green.Hard to be bluer than this! Valid in only 288 h from now! Valid on Friday, August 21st at 5 AM AST.
Some recent cloud photos
12:46 PM, August 7th. Telephone pole was going down on Linda Vista due to this microburst outflow.2:45 PM, August 7th. The Gap gets shafted. Nice.2:55 PM, August 7th. One of the great cloud bases of our time begins to take shape UPWIND of Catalina!3:03 PM, August 7th. “So round, so firm, so fully packed”, as the cigarette ad used to claim. This is looking really great for Catalina at this point, might unload right on us!. I am sure I am reflecting the excitement you felt that day.3:03 PM, August 7th. “Droop, there it is“. A report from Birdman, Rick Bowers, indicated that 1.16 inches fell in just in this storm. over there on Trotter, south end of Catalina. Only 0.71 inches in the Sutherland Heights, but still great. Fizzlerama continued as the storm headed north toward Saddlebrook with less than 0.2 inches there.3:20 PM, August 7th. Visibility, for a few seconds, down to 1/8th of a mile in TRW++, wind gusts to 30 kts or so. Now this is exciting! Temp dropped from 97 F to 72 F! This was not quite the lowest visibility.After a night of intermittent rain and thunder, dawn yesterday brought this dump on Sam Ridge, where 1.06 inches fell in an hour, 0.51 inches in 15 minutes.
Clouds got more enthusiastic than expected here yesterday, reaching sizes big enough to produce light rainshowers to the NE of Catalina, and THUNDER just after 6 PM up toward Oracle town! Nice. Looks like a small Cumulus, postcard day today in Catalina. Cloud tops marginal for ice, holding around -10 C, capped by subsiding, dry air. (Except for the light showers this morning between 7 and 9 AM; this note added at 7:32 AM when I saw a shower developing to the west over Oro Valley!) This, from the U of AZ model. Since the air is colder aloft to the N today, ice will likely be seen in some clouds up thataway.
7:26 AM, looking toward Samaniego Ridge. Water still flows down from the upper reaches of Samaniego Ridge from the winter rains. You’ll have to click on the image to really see this water.1:22 PM. Small Cumulus get underway.
2:25 PM. While Cumulus occasionally filled in, they weren’t getting any deeper. No ice visible at this time.4:11 PM. There was plenty of ice around at this time, but most of it, as shown here above and to the left of the right most light standard, ejected out the downstream end of the clouds. This meant that the ice crystals had no chance to grow inside a cloud, but were thrown out into dry air and evaporated. Wider and taller clouds were needed for even decent virga to happen.5:38 PM. Those deeper and wider clouds began to develop. Here a sprinkle or light rain shower reaches the ground toward the town of Oracle. Fifteen minutes later, thunder was even heard coming from this complex.6:45 PM. The thunderstorm that occurred near or over the town of Oracle weakens and recedes. For a time it appeared building Cu overhead of Catalina might produce a sprinkle, but no.6:50 PM. The day ends quietly.
The End.
About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
