Yesterday, after an ordinary beginning,, finished in a spectacular, if likely artificial way. Let us work our way through yesterday’s cloudulations:
7:39 AM. I thought this was a cute display by this little cloud, making its own little shadow rays as the sun made its way up from behind the Catlinas.7:40 AM. But what kind of cloud is it? It, to these eyes, is all ice, but LOOKS like an Altocumulus cloud. But those clouds are all or mostly comprised of liquid drops. And you can see that this little guy is well BELOW a higher layer of ice cloud, we might call CIrrostratus, or a thin Altostratus. Oh, well, let’s move on to something explicable….
7:41 AM. Hmmmm. Quite a linear virga feature over there. There are THREE cloud layers evident here, a thin Altocumulus layer, that dark cloud on the left, and patch of what I could call, Altostratus extending from the left corner to the right corner, and a thin layer of CIrrostratus on top.7:41 AM. Let’s go zooming and check it out…. Though we don’t know for SURE, anytime you see this kind of linear virga anomaly, you should be smelling aircraft exhaust. Now, when you think about our fabulous sunset last evening and what that looked like, take a closer look at this photo.
Later that morning…..
10:53 AM. It was nice to see low clouds topping Sam Ridge at dawn yesterday, the lower boundary layer air (where convection takes place) moist for a change. Later they devolved into small Cumulus (humilis and fractus).3:29 PM. A day with mostly ice clouds on top of Catalina, but here, off in the distance below the Cirrostratus, is an invading layer of Altostratus and Altocumulus that will set the stage for sunset glory later. You may be able to detect a faint halo, upper center. By the way, Cirrostratus typically deepens downward to morph into Altostratus, usually an ice cloud, too, but is deep enough to produce gray shading, and when its really thick or has embedded droplet clouds, hides the sun.4:02 PM. Yep, moving right in. This is a very complex scene. There’s aCirrostratus ice layer. upper right quadrant , on top of everything. Below that, what appears here as a distinctly lower separate layer, a mix of Altocumulus (those dark cloudlets composed all or mostly of liquid droplets) and Altostratus (mostly or all ice, the smudgy more diffuse dark areas) . We can never forget that Altocumulus can morph into Altostratus, which would then be called, “Altostratus altocumulotransmutatus.” Tell that to your friends! (Well, maybe not.)4:15 PM. Caught this bumpy aircraft contrail at CIrrus levels. Look how how the exhaust and water vapor that formed this, though output from an aircraft in a steady state, how the wing tip vorices (apparently) get entertwined at regular intervals with more exhaust and water vapor in those blobs.
But let’s go zooming up to flight level and take a closer look for a second:
A “mammatus” (or as the ladies like to call it. a testicularis contrail (the resemblances are pretty good). Almost certainly this is due to combining wing tip vortices. Many aircraft now have devices to defeat wing tip vortices, phenomenon that reduce flight efficiency. In both cases above, the ice particles have not grown enough to produce fallstreaks. These images tell us that SOME aircraft that produce ice in supercooled Altocumulus clouds, as we in Catalina have seen lately, are likely to have bunches of ice trails rather than a continuum if produced in a uniform cloud, anyway.
Now, where was I? Got mammatus on my mind again. I love mammatus so much… Oh, yeah, that sunset yesterday…..
5:13 PM. Ran out to check sunset status, and saw this feature advancing rapidly toward Catalina.5:18 PM. Zoomed view; getting close to passing overhead. You might be able to notice that these pretty regularly spaced trails are BELOW the Altocumulus clouds, and there’s a clearing that’s been produced. All evidence of an artificial production of these trails. But belng below the Altocu, you might also have started to wonder whether the setting sun would light them up….
And the sun did its job….producing one of the greatest sunset scenes we’ve seen in a long time, even if phony (haha):
5:23 PM. Not zoomed, still a few minutes away to overhead passage. Very exciting to think this was going to pass overhead!5:23 PM. Zoomed view. Again the pretty regular spacing is circumstantial evidence that nature didn’t do it.5:25 PM. Thank you sun! Looks pretty round again, which is good.5:27 PM. Oh, so pretty.5:27 PM. Zooming again. Wow.5:28 PM. Another view of the same thing.5:28 PM. Our trails compared to the rest of the Altocumulus deck. Not much going on elsewhere in the way of natural virga.5:29 PM. Taking WAY too many photos of the same thing. Out of control… Here I demonstrate that with another photo of the same thing.
5:30 PM. After the trail hoopla, it was time to concentrate on the fabulous sunset taking place to the southwest of Catalina.5:30 PM. Zooming in on interesting features; long trails, one with a clearing above it. Was it another aircraft-induced trail of ice and clearing above it? Probably. The trails to the left aren’t as obviously produced by an aircraft, but I do think so anyway in this burst of objectivity. Recall that I have been trained as a “scientist” and don’t care if I am wrong, but only about truth, as best as I can make it out.
Finally, let look at the TUS sounding for last evening, see how cold those Ac cloud were with the ice trail in them:
Results of the Tucson rawinsonde balloon launch yesterday at about 3:30 PM. Goes up at about 1,000 feet a minute, so takes about 100 minutes to get to 100, 000 feet. They pop somewhere around that height or a little above. THought you like to know that. They have a little parachute to that when they come down, they don’t bonk you too hard. Once in awhile people find them in remote areas downwind. You can send them back in to the NWS, too!
The astounding thing here, something that goes against everything I believe about clouds, is that it is indicated that the Altocumulus, lacking much natural ice, was at -30° C! Yikes! No wonder aircraft were producing ice trails and stuff yesterday afternoon.
You have to conclude there were almost no natural “ice nuclei” up there at, oh about 24,000 feet above sea level. This is not the first time for such an occurrence of liquid clouds sans much ice at low temperatures1, but they are rare IME. This would never occur in a boundary layer cloud, that is, one where material from the earth’s surface is getting into the clouds, like the omnipresent dust, or biogenic ice nuclei.
The weather ahead
Some “fantasy” storms with rain in them for Catalina, are now seen on the model predictions beyond a week. Spaghetti is favoring this new development now. So, something to keep an eye on.
The view from here? Precip here is “in the bag” because going on subjective feelings, I really want to see a good rain here!
The End
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1The famous John Hallett said he saw an Altocumulus lenticularis sans ice at -35°C in a conference preprint! Rangno and Hobbs (1986) claimed to have detected droplets in Altocumulus like clouds at the top of a storm on the Washington coast at -44°C. Their claim, first published in a conference preprint, was later rejected by the J. Atmos. Sci.
The full moon of December 11, 2008. Thought maybe you’d like to see it in case you missed it, or see it again if you did see it. Maybe you had a special memory with this moon.7:09 AM. Altocumulus perlucidus with a little lenticular underneath.7:10 AM. Zooming and zooming.7:10 AM. Zooming some more.7:14 AM. Iridescence is evident in the cloud ripples just above the mountain silhouette.7:16 AM, Contrails were soon visible in our Altocumulus layer, the aircraft making it at the right edge of the photo. Appeared to be in a climb out going right to left. And, when you see these “high temperature contrails” in Altocumulus, you can be sure ice will form and rifts will develop as a little bit of light snow develops and falls out. The jillions of ice crystals in the contrail cause the droplets in the Altocumulus to evaporate, in a way, gutting it. An ice crystal is like a low pressure center when amid droplets; the droplets evaporate and those water molecules deposit themselves on the ice crystal, a process named after the discoverers, Wegner-Bergeron-Findeisen. Eventually the crystal is large enough to settle out and a clear streak results unless the air is rising rapidly and can replace the droplets (as generally happens in storms). Sometimes the lift in the Altocumulus layer is enough that a clear canal caused by an aircraft can fill back in after many minutes.7:18 AM. Two aircraft contrails, about a minute old. After two or three more minutes, they will not be visible within the cloud, though ice is forming, decimating the droplets around the intense streamers of ice in the contrail.7:28 AM. The small ice canal (the ice is hanging just below the Altocumulus clouds–kind of hard to make out, but its there.7:42 AM. Those little clear streaks are hardly noticeable now, partly because they were quite narrow, and because of perspective and things bunching up in the distance.
Suggested locations of cloud layers. The Altocumulus layer in which the contrails were embedded seems to be at -25°C, a “normal” temperature for this kind of “high temperature contrail”. In general contrails are not supposed to occur until the temperature is below about -35° C and the air is moist, thus they are usually seen amid or near Cirrus clouds. not down in Altocumulus. See usual contrail height at Cirrus levels in moon photo.
As the morning wore on, the Altocumulus deck faded away, moving east, and we were left with some Cirrus clouds, but what kind?
10:58 AM. Cirrus of some type, but notice there is absolutely no fibrous details (strands and such) as we normally see in Cirrus. Could be transverse waves in a Cirrostratus deck since Cirrostratus can be fog like, have no detail, in a version we call, Cirrostratus nebulosus. The up and down motions would cause clearings perpendicular to the wind up there. The lack of strands and uniformity in these bands suggests very tiny ice crystals, ones having very little fallspeeds.2:34 PM. Some nice “hovercraft” clouds, Altocumulus lenticularis off in the distance SSW. Hung around out there for a couple of hours.3:17 PM. This one appeared to be concave upward, which was a little odd. Zoomed view next.3:17 PM. Looks like the inside is higher than the outside. Huh.
Well, that was it for photography yesterday.
Doesn’t seem to be any reliable indication of rain in sight. Oh, sure, rain here pops up in the models almost every day, but its about 12-15 days out. As the model gets closer to the day it predicted rain, it seems to go away like the “water mirage” on a hot paved road; always ahead of you, but you never get to it. We’ve had some major rains indicated in the models as of a few days ago, but spaghetti was never very high on those events (clustering those crazy lines in a trough over us), so it wasn’t even worth mentioning.
Many strange1 and wonderful sights were seen yesterday; I could feel the excitement out there as one cloud microstructural mystery after another regaled our Catalina skies.
7:24 AM. Here, a tiny highlighted flake of Altocumulus floating above a mass of light snow/ice crystals, maybe straight below it. This is one the classic mysteries we deal with in “cloud microstructure”; the oddity of nature preferring to generate a droplet before an ice crystal at least to somewhere in the -30°s C. Liquid clouds often are at the top of Altostratus and Nimbostratus (rainy or snowy days) providing the tops aren’t too much colder than -30° C. How strange is it to have liquid water at the lowest temperatures in a cloud system, with all the ice and snow underneath, as shown in this photo (though here they are no longer connected).7:24 AM/ I think there is itty bitty droplet cloud at the very top bright dot there. A droplet cloud was likely much broader to have produced all the ice we see below that bright dot of liquid cloud.7:26 AM. Looking afar, to the SW, there’s what appears to be an Altocumulus (droplet cloud) with a few ice crystals underneat it, especially to the right.
How cold are these clouds? Lets look at the TUS sounding, launched at about 3:30 AM yesterday morning.
The TUS rawinsonde balloon data for yesterday morning before dawn. That Altocumulus layer, and the other clouds above were likely at the pinched point above, topping out at -27°C and up around 23,000 feet above sea level (400 millibars), pretty darn cold. But, as you saw in the 3rd photo, not a lot of ice is being generated at this temperature by that patch of Altocumulus clouds to the SW. Not sure why, but its pretty remarkable and that is likely due to small droplet sizes AND a lack of ice nuclei, most of which are known to originate with soil particles When you see these rare occurrences of all or mostly droplet clouds at low temperatures (<-20° C in particular, get ready to see hole punch and ice canals produced by aircraft, a kind of inadvertent cloud seeding.
That bank of Altocumulus was racing at more than 50 mph toward Catalina, and so it got here in a hurry. And, as it got closer, it was also getting more into some airways at that height, possibly descents into PHX since the height of those clouds was below normal jet cruising levels at 23,000 feet Above Sea Level.
7:55 AM. This is one of the strangest sights I have ever seen. Why? On the left side of this photo, the clouds are completely glaciated, composed of ice, while along a line to the right, there’s no sign of ice in Altocumulus clouds that appear to be at the same height (namely, temperature). I have no explanation for this scene, except those involving a lot hand-waving, so we’ll just let go, except that we speculate that the Ac layer was a little lower (warmer)? Could have been.
Now for the aircraft effects. Hardly a few minutes go by before aircraft began marking up this cold Altocumulus layer. Notice that it doesn’t seem to be producing much or any ice on its own, making aircraft inadvertent seeding lines and holes where tremendous numbers of ice crystals are generated immediately present. Here’s the first of many:
8:16 AM. An icy canal due to the passage of an aircraft rips through this pristine layer of Altocumulus whose temperature was around -25° C. The view is looking S toward Tucson, but is unlikely to have been an aircraft landing there because this layer was above 20,000 feet Above Sea Level. An aircraft lanidng at TUS would be much lower, this close. The passage of the aircraft was likely 10 or more minutes before this photo.8:19 AM. The ice canal is broadening due to turbulence, and ice is not plainly evident to all Cloud Maven Juniors or we will have to go over discerning ice from droplet clouds at the next club meeting.8:20 AM. A view of the northwest end of this aircraft-produced ice canal. Several others became apparent, too.
Heading for Catalina, this:
9:11 AM. Heading for Catalina, a whole mess of aircraft induced ice in that poor Altocumulus layer. The hole punch was likely due to an aircraft climbing out of or descending into TUS. The age of a hole that large, with ice below it like this would be something of the order of at least half an hour to an hour old. Just behind the hole is a new contrail in the Ac clouds,9:23 AM. Hole punch area and ice canal arrive over Catalina! Losing control here, taking photo and photo, now looking for stragne optics, usually observed with aircraft produced ice particles because they are so numerous, compete for the available moisture and therefore remain tiny and perfect, prisms, plates, short column ice crystals, ones that can do a lot of optical stuff.
Here’s the south end of that ice canal:
9:24 AM. Also note iconic horse wind vane, and real wind vane atop a personal weather station. Doesn’t everyone have a “PWS”?
Looking straight up at the icy heart of a hole punch region caused by an aircraft. I am sure you have never done this before! This is gonna be a great blog with all these new things for you!
9:27 AM. Look at the detail in the ice, those fine, fine strands! Amazing. The thickest strand might be due to the higher liquiid water in the heart of one of those little Altocumulus cloudlets. ??? Look how much wind shear there is, those little itty bitty ice crystals falling so far behind the parent cloud, the streamers flattening out because the poor little guys, already undersized to begin with, are getting smaller and smaller, the fall velocity getting less and less until the strands are almost horizontal.9:27 AM. Looking at this gorgeously uniform layer of Altocumulus perlucidus 9honeycomb of elements) translucidus (no shadows). To me this is a phenomenal scene, though maybe to u, not so much, which is understandable.9:30 AM. The expected intense optical phenomena began to occur in these aircraft contrail remains. Here a parhelia, or sundog. More fireworks in a bit.9:30 AM. While the parhelia was in its full display, very intense, this was the ice canal passing overhead. Look at the regular spacing of these strands of ice, Might be due to the spacing of the cloudlets in the Altocumulus layer, the spaces between them not producing much ice, or, as we know, contrails tend to clump behind the aircraft likely due to wingtip vortices interacting and combining masses of exhaust water and crud. This is now about an hour and fifteen minutes old, since we saw it way out to the west at 8:16 AM shortly after it formed.9:37 AM. Here’s what a new aircraft contrail in these clouds looks like, this one about 60 s old looks like. Note all the irregularity in the contrail from the get-go.
As the south end of the original ice canal began to enter the refraction zone for simple ice crystals around the sun, usually at the 22° degree halo position, things began to light up with a particularly bright circumzenithal arc (more often observed on a halo) or colorful (in this case) partial “reverse halo”. The colors (iridescence) due to the refracting of light within very small ice crystals. Normally iridescence is seen near the sun in Cirrocumulus clouds or the then edges of other droplet clouds. Very exciting.
9:44 AM. A part of a halo curving in the wrong direction, away from the sun! (This is actually called a circumzenithal arc).9:44 AM. Taking up you up thousands and thousands of feet via a zoomed view. Pretty cool, eh? Notice how much its moved in just seconds, You really have to let your coffee get cold if you’re a photographer and you want to get the best shots of this kind of phenomenon. You really can’t do anything but keep watching every second!9:44 AM, again. All these changes took place within the minute between 9:44 and 9:45 AM! Here, the next grouping of ice strands is being lit up.9:48 AM. Just a pretty scene. Altocumulus perlucidus translucidus, pocked with aircraft contrails, if you look real close. Make me move: $1 billion dollars…9:54 AM. Its not even 10 AM and now this comes along, this fabulously complex zone of CIrrocumulus (at the same level of the Ac clouds) at the tail of the Altocumulus. You can see the much higher Cirrus going crossways, lower center. See TUS sounding for height of Ci.
Then this strange sight:
12:29 PM. A row of Altocumulus or Cirrocumulus, each formed by a little upward bump in the atmosphere of a layer just a hair below saturation. Just rising a few hundred feet or so causes these cloudlets to form. Why aren’t they everywhere? Might be drier. Bumps like this are always present in the atmosphere, especially if there are mountains upwind. Not taken while driving, of course, ; just looks like it thanks to photoshop.
The day closed out with a lower layer of Altocumulus moving in, this layer, according to the TUS sounding, at “only’ -17° C, and little ice detected. Below, at 2:09 PM:
2:09 PM. Altocumulus perlucidus translucidus. A natural conversion to ice is occurring on the right side of the photo.4:42 PM. So pretty these Altocu.
4:41 PM. A strand of finely patterned Cirrocumulus shot out of the SW as the sun declined.The Tucson afternoon rawinsonde . launched around 3:30 PM. The Cirrocu in the above photo was likely also at the Cirrus level indicated above.
U of AZ mod thinks so light rain will develop around here in the mid-later afternoon.
The End
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1“stragne” above, originally an inadvertent typo, but left in place as another cheap trick to get draw the curiosity of readers who might wonder what stragne is.
Yesterday, whilst disappointingly dry, no rain fell here overnight was a day of rare cloud sightings, most of it involving the rarely seen, “Cumulo-cirrus1“, a cloud fakery situation where extremely cold (less that -40°Ç, -40° F)and clouds at Cirrus levels appear to be ordinary little Cumulus fractus clouds. I hope you weren’t fooled by those impersonators. You’d be pretty embarrassed at the next meeting when we go over yesterday… Yesterday was, in essence, a test for you, and I hope you passed.
Along with the rare “Cumulo-cirrus” sightings, there were intricate patterns in Cirrocumulus clouds that may have caught you’re eye. However, with the wind aloft being so strong (around 90-100 mph at 18,000 feet) you didn’t have a lot of time to enjoy them.
Yesterday’s clouds
10:01 AM. These were the first “Cumulus” pretenders I saw yesterday, though I suppose the discerning eye might have called them “Altocumulus” as well. When they first formed they look hard and rounded like they might have had cloud droplets. But then within seconds, that brighter look caused by high concentrations of droplets or tiny ice crystals (sometimes called “germs” because they have no particular shape when just formed) fades as the concentrations decline rapidly due to evaporation and mixing with the dry environmental air around them. Eventually, they become transparent. Also notice that you don’t see trails come down out of them. This is likely because the concentrations are so high that competition for moisture keeps all of the ice crystals so small they can’t really fall out.10:01 AM. Zooming in. The brighter ones have just formed. The faded ones are the older ones heading for extinction. Many more shots of “Cumulo-cirrus” to follow. Got kind of carried away, as usual.10:18 AM. Another moist layer shot in, first showing up as Cirrocumulus, though this cloud was in the middle levels, not at Cirrus heights. The fine granulation makes it look higher than it really is. This was probably around 12, 000 feet above the ground, if that. One giveaway was the rapid movement of the cloud itself, and compared to the cirriform clouds above it. If they are near the same levels, they won’t move much at all relative to one another. Anyway, these patterns changed by the SECOND! It was amazing how quickly they devolved into something completely different.10:27 AM. A wid angle view of another incoming group of “Cumulo-cirrus.” The thinnest clouds are the ghostly remains of those clouds. The more compact and brighter ones are the youngest ones.10:27 AM. A closeup of a just formed globule. Everything around it was onece like that but now has the visual attributes of regular Cirrus.10:42 AM. One of the strangest cloud sights ever seen by yours truly, CMP. Here a layer of Cirrocumulus (note fine patterns lower center) passes rapidly underneath those globules of fake Cumulus clouds full of ice.
Explanatory figure below:
11:22 AM. Another patch of fake Cumulus fractus at Cirrus levels comes by. Note the true Cirrus in the background, and was higher than the fake Cu fra.11:36 AM. Was beside myself seeing this! Just incredible!11:38 AM. Just two minutes later! Look what has happened to that puff ball of ice. The turbulence up there must have been tremendous.11:57 AM. Some real fakery here. Ordinary people would have said, “Oh, those are just little Cumulus fractus over our Catalinas.” But not you. You would have chided them in friendly, gentle way, telling them they were WAY too high for Cumulus clouds and are mainly composed of ice, not possible for low Cumulus fractus clouds. You could have also pointed out that the cloud in the upper part of this photos were way below those Cumulus fakeries, and that they about to obscure them as this encroaching layer slid underneath them. Also, try not to be condescending, act superior like you know so much even though you do. You might lose your friend if you do that.11:53 AM. Another zoomed view of one of those icy puff balls, not long after it formed.4:01 PM. Altocumulus opacus underneath a Cirrostratus layer. A great sunset was in the works with that opening to the southwest. Also notice, no ice or virga evident. Guess that the temperature at the tops of this layer, likely only a couple of hundred meters thick, is warmer than -10° C.5:31 PM. Altocumulus opacus at sunset. The height of this layer was about 8,000 feet above Catalina by the TUS sounding, top temperature about -5° C. “No virga, no cry,” as Bob Marley said.
The End
————— 1Though it fits, I made this cloud name up. Probably would be Cirrus floccus, maybe Cirrus castellanus in the humped up cases.
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.
Not much else to talk about, no rain of course; what is that?
But with so many colorful scenes yesterday, we can be partially sated by the lives we lead here sans rain here. October ended with a puny 0.01 inches in Sutherland Heights.
Now, because I grew up in California and remain a little Cal-centric, this brief diversion from AZ:
But droughty Cal got nailed though, from about San Luis Obispo, so we can be happy about that I guess. One station, Gasquet RS, near the Duck border, got just under 28 inches in October; stations in the Santa Cruz Mountains, way down by Monterrey, got between 14-17 inches! From the California-Nevada River Forecast Center, this nice map of October rainfall anomalies in that domain. Red is real dry, and that’s the color we would be in if it was the California-Nevada-Arizona River Forecast Center:
Many departures are far over the map color-coding limit of 350%, but are over 1000% of average! Note red below normal swath. This tells you that the mean area of low pressure at the surface and aloft was just off the West Coast. Pac NW set maximum October rainfall records, too.
But let us not dwell any more of generous rains that others got, but celebrate the color and clouds of Arizona. Here are yesterday’s glorious scenes, beginning with a spectacular Altocumulus lenticularis under some Cirrus at dawn:
6:37 AM.6:47 AM. Ac len stack.10:51 AM. Tiny patch of Cirrocumulus tried to hide in front of some Cirrus. Hope you weren’t fooled and logged this sighting in your cloud diary. Cloud maven person almost missed it himself.12:50 PM. There were lenticulars aplenty yesterday. Here’s another one in a location a little different from normal, beyond the Catalinas. Upwind edge is the smoothest one at right. No ice streamers coming out the downwind end, so must have been pretty “warm”. Lenticulars, due to their tiny droplets and those droplets having short life times, have been known to resist ice formation to temperatures well below -30°C -22° F). Pretty amazing.2:42 PM. Kind of clouded up in the afternoon, and with breezes, made it seem like something was up. It was, but far to the NW of us. We have been under a streamer of high to middle clouds originating deep in the Tropics for a couple of days. Here some lower level moisture has crept in on cat’s feet, to be poetic for a second, and has resulted in small Cumulus and Stratocumulus clouds underneath the Cirrus and lenticulars standing around. All in all, though the temperature here reached 87° F, a very pleasant day.
Now, just some nice lighting and color:
5:32 PM. The almost flourescent plant in the foreground is what is known as a “cholla.” The end elements fall off quite easily and attach to things like your pant leg if you brush by them on a horse, or if back into them while walking and correcting your horse for something when he’s acting a little “wild.” I can report that when seven or eight of them are stuck to the back of your shirt, its really hard to get that shirt off. In fact, it just about won’t come off without a major scream.5:35 PM. The higher Cirrus are shaded by clouds to the west, but the lower remnants of Stratocumulus/Cumulus and a few Altocumulus are highlighted as though they were meant to be for this photo. So pretty. Notice, too, how there seems to be more than one layer of Cirrus.5:44 PM. Cirrus and Altocumulus, the latter with some turreting making those the species, “castellanus”, if you care.5:47 PM. A nice flame-out of Cirrus occurred as those pesky clouds blocking the fading sunlight from striking them opened up below the horizon. A few Altocumulus castellanus can be seen, too, but relegated to shadow status.
In a further celebration of dryness here, let us examine the rainfall cumulative rainfall predictions calculated by the University of Arizona’s Dept Hydro and Atmos Sci computer the period ending at Midnight on November 5th. Says the coming rain in the State misses us here in SE AZ while falling just about everywhere else, of course. Dang. Let’s hope it one of the worst model predictions ever!
This really poor forecast is based on the global data from last evening at 5 PM AST.
7:25 AM arrives as usual. Seeming radiating bands of Altostratus stream toward Catalina (little too thick and gray to be “Cirrus”). They also appeared so smooth as to resemble lenticular clouds.1:14 PM. Since its summer again in Arizona in late October, not surprising to see afternoon Cumulus clouds originating in air from the Tropics clustering over our mountains again.1:38 PM. The curved brightening at the bottom of this otherwise normal halo is likely a “lower tangent arc.”1:40 PM. Zooming in with excitement here. Is it really a lower tangent arc? Not positive, but will go with that description anyway.2:59 PM. That Cirrostratus thickened into Altostratus (usually, btw, due to the bottom of the cloud lowering) and at the same time the lower moisture, evidenced by these Cumulus and Stratocumulus clouds, also increased. However, none of these lower clouds got cold enough to produce ice, so likely tops were warmer than -10°C (14°F).
4:32 PM. Mix of Altostratus and Altocumulus clouds, with just remnants of the lower Cu. Here it appears that a liquid layer of Altocumulus now resides at the bottom of the Altostratus, or may be embedded in it. The globular masses in the middle of this photo represent droplet clouds that appear to have merged into a plate. In the distance, the telltale sign of lowering tops: only droplet clouds, with a occasional splash of virga can be seen.
5:23 PM. Just a little before a great sunset, which I missed due to a social engagement, the shallow Altocumulus droplet clouds are plainly evident around the sun’s position. Above to center, the backside of the deeper Altostratus clouds with much higher tops, is about to pass over us. Here you can see, how much lower the Altocumulus cloud fragments are than the Altostratus layer as they are illuminated by the sun (upper center highlighted clouds).
All in all, a pretty pleasant day with interesting clouds passing by, though ultimately disappointing since at one time, this was to be a day with showers here. Oh, well, that’s weather forecasting for you.
Another minimal chance for showers comes up in the middle of next week…
Not as good as a rain day with lightning, but yesterday did have its moments in the sky, enough to make the astrologers on Mt. Lemmon jealous with displays of parhelia (“sun dogs”, or “mock suns”), faint haloes, a rare parhelic circle, something you don’t see but once every year or two, and fallstreifen (fall streaks) from Cirrus uncinus clouds going in almost opposite directions, an extremely rare sight.
The rare “parhelic circle” is a local brightening often extending out from a parhelia (sun dog) at a sharp angle, which I just learned about here1. Usually you don’t see a whole circle, just part of one.
These optic displays are caused by ice crystals, of course, ones not too complex, but rather simple ones like prisms, short solid columns, bullets, and hexagonal plates. Some examples of these can be seen here.
The bottom of yesterday’s moist layer was just above 30,000 feet at a temperature of -35° C and extended all the way up to about 40,000 feet above sea level where the temperature were around -65° C.
The balloon sounding launched around 3:30 PM AST yesterday from the Banner University of Arizona.
Some photos documenting the excitement of yesterday
5:30 PM. Cirrus uncinus crystals heading in two very different directions. Wow. Notice the fibers from the contrail that are starting to fall out are going in the “correct” direction, back toward that west or southwest.3:04 PM. Parhelic circle erupts in mostly Cirrus uncinus clouds.3:06 PM. The astounding sight continues, but fades away just after this.3:33 PM. Local brightening at the position of a sun dog suggests these are tiny ice crystals or possibly even droplets that have just formed, the sizes too small to allow refraction into color normally seen in sun dogs.3:32 PM. A zoomed view of that little bright spot. Sure looks like it may have been droplets. Droplet clouds have been reliably reported to temperatures as low as -44° C. Of course, wouldn’t stay liquid long! I thought this was a pretty exciting shot! Hope you got it, too.
3:42 PM. Amid all the optical excitement was this ghost-like halo. Can you make out the faint circle around the sun? In ascents through thick ice clouds having complicated ice crystals like bullet rosettes down below the tops, as you climb to the top of such clouds, amazing haloes can be seen where the crystals are newly formed and quite simple in structure, allowing the refraction required for a halo. So, this halo was likely at the top of these thicker Cirrus and Altostratus (dense portions) clouds, though no one would penalize you if you just said they were all Cirrus clouds.
3:59 PM. Another spectacular bright spot at the sun dog location (which is also at the 22° halo location, faintly evident here).3:59 PM. Zoomed view of this sun dog/parhelia. Lots of fine structure evident, which is not usually the case with parhelia.4:25 PM. Another finely structured parhelia/sun dog suggesting the ice crystals were newly formed. Fine structure like this can’t last long with the usual turbulence, and so that’s a sure sign this feature has just formed. I don’t recall seeing so many atypical sun dogs in one day!5:09 PM. The normal, amorphous sun dog. No really fine detail can be seen here.
Below, examples of cold Cirrocumulus, ones that quickly transition to Cirrus clouds.
5:19 PM. This group of CIrrocumulus clouds appeared very quickly almost overhead. The tiniest elements are those that have just formed. These are composed of ice crystals in extremely high concentrations, perhaps 10,000 per lilter. Once that ice has formed, its gradually spreads out, much like a puff of smoke would, thinning, some crystals growing large enough to start fall steaks.5:19 PM. Some elements are still forming, but the spreading of the older ones is well underway, producing a “blurred” look as the elements merge and thin out.5:28 PM. Off to the southwest of Catalina, a promising intrusion of lower moisture indicated by these approaching Altocumulus clouds. Will there be enough today for a sprinkle somewhere? Not looking so good now, clouds did not lower much overnight. Well, maybe if it doesn’t sprinkle, maybe we’ll get to see some nice virga and dream about rain…
A horse photo will always enhance a blog about clouds. Expecting a little uptick in readership due to this ploy, maybe will break out of the single digit column.
Not much happened early on, a thin film of Cirrostratus covered much of the sky, delaying the expected development of convection, as would be evidenced by the formation of Cumulus clouds, until mid-afternoon.
But they did form, mostly to the S through W of Catalinaland, upwind of us, and eventually rumbled in on their last legs as weak thunderstorms with gushes of sprinkles and gusty breezes, maybe ones over 15 mph!
Over there in Marana and Avra Valley, those places upstream of us, some spots got more than half an inch. But, i it seems this year that storms die when they move toward Catalina, and especially, toward MY house and its many raingauges (3).
Still, it was nice to feel cool breezes, air chilled by falling rain, even if elsewhere.
Here are a few dull and disappointing cloud shots from yesterday, including one with a horse:
10:56 AM. Horse looks ahead, examining the vellum of Cirrostratus cloud overhead, wondering if it means anything. If this was Seattle, such a layer would thicken and lower into a steady rain within hours 70% of the time. Pretty true for most higher latitude locations in the cooler time of the year. (This was horsey’s first true trail ride, going up and down rocky gullies with loose rocks along side the Sutherland Wash. Previously this horse had spent most of its 14 years in a small corral so this was all pretty new to him; rider tension high.)2:49 PM. A soothing gray of Altocumulus undercut the layer of Cirrostratus. Building Cumulus clouds can be seen toward the Mexican border on the horizon. Pusch Ridge is in the foreground. As you can see, no virga is falling from those Altocumulus clouds, so they must be pretty “warm”, warmer than about -10° to -15° C at cloud top.3:38 PM. Looking suggestive of rain here in Catalina. However, these storms were in the late, dissipating stage. Note too how the anvils have merged with the Cirrostratus layer and lean far out from the storms toward us, helping to cool the ground, ruin the chances of new Cumulus buildups ahead of them.4:19 PM. Not much going on over the Catalinas. Notice how broken up into light and dark patches these otherwise dark looking lower clouds are. Shows there’s no hope for any buildup out of them, though, lower clouds like these under precipitating Altostratus cumulonimbogenitus (that higher cloud here which is really the result of anvils) can help sprinkles get to the ground. That’s because drops or snowflakes falling out of the higher cloud, won’t evaporate while falling though these clouds (representing saturated air with respect to water).4:33 PM. Nice shaft, some cloud-to-ground lightning strokes toward south Tucson, but who cares? Wasn’t moving this way, and would be mostly dissipated by the time it got here anyway.4:57 PM. Some rain with an occasional lightning outrage did reach the southern parts of the Catalinas, eventually making it all the way to Ms. Mt. Sara Lemmon where 0.24 inches was recorded. SPKLS fell in Catalina.5:42 PM. Last gasp, last chance for rain here, dying shower with some new bases to the right, offer another slight hope that the new stuff will develop into showers like this one. It didn’t.
Still have rain chances last few days of Oct into early Nov.
No rain in sight for Catalinans, to get that over with.
However, if you’re bored and are thinking about a quickie storm chasing vacation with the family, monster storms, likely to produce newspaper headlines will be smashing the Pac NW in the next few days. Expect to read about flooding and hurricane to 100 mph winds on the Washington/Oregon coast sometime. Also, Tofino, British Columbia, along the SW coast of Vancouver Island, would be a great place to head for, watching giant waves crash up against the coast and around that lighthouse they have around there, pounding rains…
The long fetch with these storms in the Pacific guarantees some monster waves.
3:49 AM, 14 Oct: Mark “WeatherPal” Albright informed me that a 94 mph wind was observed last evening (the 13th) near Astoria, OR.
The next low, a “regular low” but one energized by leftover moisture from Typhoon Songda, looks to be even stronger than last night’s low. This one comes in moving really rapidly tomorrow evening while deepening (central pressure is dropping further) as it passes over the Washington coast. Looks like that one will be a “blow-down” storm; good-bye timber.
The synoptic pattern (placement of jet streams and lows) is “Freda-esque”, that is, similar to that of October 12, 1962, the infamous Columbus Day storm where a remnant of Typhoon Freda zipped in as a regular low that deepened explosively as it raced up the Pacific NW coast bringing winds of 100-200 mph and blowing down BILLIONS of board feet of timber as well as weather pal, Mark Albright, mentioned above, when he was a kid1.
Well, we sure hope its not THAT similar!
Yesterday’s Clouds
Lots of interesting patterns and complexities in yesterday’s skies. If you didn’t see them, here they are, though its kind of a much ado about nothing, really:
1:23 PM. Icy Cirrocumulus. As a solid band of high and middle clouds approached, the first things we saw as the moisture began to increase aloft were some spectacular patterns in isolated high clouds as the solid band approached. Probably most of the Cirrocumulus we see is composed of droplets, and never glaciates, but here, it appears to be composed of ice, though likely started as droplets at the upwind edge (middle of photo). At the top of the photo, the tiny “granulets” are fibrous, clearly ice, and strands of ice crystals are starting to make their way down.1:23 PM. Got excited and thought you might like a zoomed view of this patch in case you didn’t get one.1:30 PM. I thought this was kind of a strange and fun pattern for you. Look how the youngest cloud elements are over there beyond the Catalinas and the oldest ones with strands of ice crystals falling out are overhead. Besides perspective giving you a sense of radiating lines, one would normally guess that the wind way up there (about 30 kft above the ground) is heading toward you, newest cloud (Cirrocumulus, maybe lenticularis) back there, oldest ones arriving overhead, which would be from the south in this shot. But the wind was from the west-southwest at this level, perpendicular to this scene. Can’t say either of us has seen this before; quite the “Tom Foolery” in a cloud scene, a real knee-slapper. Clouds do that a lot where we think we know what is going on, but, as they say, “upon further review”…..1:32 PM. Confusion? Strands of ice and waves in this cloud that produced lines seem to run in various directions. Some lines are perpendicular to the wind, blowing from the lower right to the upper left side, representing little bumps in the air, ones resembling sea swell rolling in to the shore,1:40 PM. Pretty much unfathomable, too complex to even begin describing in less than a page, which makes it worth photographing. We can make out what CMP deems as some icy Cirrocumulus though, here and there, with that lenticular-looking backside beyond the mountains, though perspective may be bunching it up to look that way. I’ve already taken too many photos in just eight minutes!2:10 PM. Breathing easier now, here, “simple” Cirrus fibratus, lined Cirrus clouds with mostly non-curving fibers,Also 2:10 PM. The scene upwind of that “liney” Cirrus. Also “fibratus” except overhead there looks to be “uncinus” as evidenced by those thick regions (upper right hand corner) likely trailing ice strands back toward the viewer.2:18 PM. Pretty soon the heavier masses of CIrrus (Spissatus) with some gray shading began to appear, with lower, but still very cold and at least momentarily, Altocumulus droplet clouds (above bush on the right) began to appear just below the Cirrus. Clouds almost always lower in time, even when they don’t lead to a storm.2:18 PM. More patterns. Here we have a mush of Altocumulus, very fine granulation of Cirrocumulus (top) and CIrrus clouds passing overhead. You can tell if clouds are at different levels by looking to see if they are moving all at the same rate. Here, if you looked really carefully, the little white tufts of Altocumulus clouds were moving in a slightly different direction than the Cirrus clouds were. How important is this. Not too much.4:18 PM. Skipping ahead, the full boatload of this band, consisting of a thick Altostratus, was passed over at this time. The clearing on the right told you there was going to be a nice sunset in a couple of hours. This was the lowest level the moisture got to. somewhere in the 22-25 kft above the ground, according the the TUS sounding though the darkness of it may make it look lower.6:01 PM. Almost could have been a painting. VIncent Van Gogh himself could not do this scene justice. If you’ve seen his work, like “Starry Night“, you’ll know how bad he was at capturing the sky. But for him to try to capture this scene, it would be beyond “bad”, but rather a total and complete travesty,. The gradual ascent that produced the heavy line of Altostratus is now being broken up by patches of downward moving air, leaving holes and streakiness in the former solid cloud shield. But who cares when you can just sit and take scenes like this in!6:06 PM. The moon amid CIrrus spissatus and other varieties of Cirrus. Notice that the disk of the moon is just a bit blurry, out of focus. That blurring is due to ice crystals in those Cirrus clouds. If it was a thin droplet cloud, the disk would appear crisp and very sharp..
—————————- 1Mark. like most kids who are blown over in a windstorm, wanted to be a meteorologist right after that. Its pretty traumatic and life changing when you’re blown over by wind. CMP’s life was traumatized and changed forever when it snowed a few inches in the San Fernando Valley of southern California when he was six year’s old. Not sure you’ll find this information in the latest Diagnostic and Statistical Manual of Psychiatric Disorders #5, however, but its a well-known phenomenon in the weather subculture.
