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.
“Can’t you see, I’m on a losing streak” Rolling Stones1, 196x, in “I Can’t Get No Satisfaction”, a “PG” for radio tune from those days.
Well, it seems we “can’t get no satisfaction”, either, when it comes to rain
Being on a “losing streak” has been CMP’s fate as well as far as forecasting goes. A few weeks ago, right here on this blog is was reported that CMP was “on record” that November would end with a flourish of rain that would boost totals “to above average.” That statement has now been excised from that earlier blog; there is no longer ANY “record” that I said anything like that.
November ended up with 0.70 inches, whilst average is 0.96 inches.
Then, in a wild one, it was suggested strongly a ten or so days ago here that snow and cold would make the Catalina snowbirds feel right at home, the one they left to avoid snow and cold.
Well, that’s not gonna happen, either.
On the good side of things, distracting the reader from the many erroneous forecasts found here, CMP’s former employer’s fubball team, the University of Washington Huskies, are moving on to the Final Four of Division I fubball after bonking Boulder Buffaloes 41-10! This means a gigantic media paycheck for the U-Dub! As you likely know, Big Fubball supports all the little sports that can’t support themselves with revenue, like softball, cross country, volleyball, and the like, so many of those that come under Title IX. So, its a good thing for everyone, but in particular, especially women’s sports, when you’re university gets a big media paycheck, one that’s spread around the whole conference!
Now, where was I? Oh, yeah….bad forecasting.
The cold air, and any sign of precip will remain far to the north of southern Arizona. Spaghetti really let me down in that one, or my interpretation thereof. Not really my fault at all, when you get right down to it…
The current low spinning over southern AZ and northern Mexico was formerly a situation where precip was going to fall here according to computer models. Now, as our “losing streak” for storms continues, its going to end up as a “high, dry one” for us. Parts of Mexico, NM and points east will get generous rains and snow, so we can be happy for them, I guess.
On to clouds, for what its worth. There were some nice scenes again yesterday.
8:36 AM. Nice line of Cirrocumulus I would call it, some cirriform clouds in the background, maybe Cirrostratus fibratus (has lines, fibers in it).
9:57 AM. Action shot. This photo gives the feeling of clouds streaming at you, which they were; Altocumulus upper center, maybe Cirrostratus above it, and to the left and right horizon.1:16 PM. Things started to look promising as distant light rain showers broke out to the southwest. Perhaps they would work their way into Catalina. Nope.1:19 PM. The sun’s disk as seen through a cloud that is completely or almost completely comprised of droplets, hold the ice. Ice particles, if in any degree of concentration, caused the sun’s disk to blur, you would never be able to make out the edges due to diffraction of light by those larger particles. Droplets in clouds are mostly less than 20 microns in diameter, whilst ice particles are generally larger than a few hundred microns to millimeter sizes. Here, you could have told your tell your friends, if you have any, that this cloud is all or almost all comprised of droplets, probably no ice at all. Some kind of bird is passing off the frame of this photo, maybe a seagull.3:54 PM. The day ended in disappointment, a word used a lot these days as those minimal showers rotated westward and stayed far to the south.
Now, there’s nothing in sight in the way of precip for southern AZ, not even an outlier model forecasts of some fantasy storm to dream about in the next two weeks. Oh, well, we can enjoy some nice sun and feel the warmth that sun brings
———— 1This is a really old R&B, rock band led by Mick Jagger. Mick will be 100 years old I think next year, and so they’ve cut back on touring; only 47 shows are planned in the US.
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.
Oh, well. Was expecting at least 0.25 inches a few days ago, and thought maybe a heavy shower last night might pull that expectation out of the trash bucket. Monthly total now up to 0.70 inches (updated after reading NWS-style and CoCo gauges here), still significantly below average (0.96 inches). Not much else elsewhere, either. Double dang.
Mostly Cumulus humilis and flat Stratocumulus yesterday. Was looking for ice as the temperatures aloft cooled during the afternoon and evening, and only as the sun went down was a slight bit of virga visible to the west. That Stratocu deck over us was deepening upward, and began reaching the magic point where ice begins to form, probably around or a little below -10° C (14 °F) in clouds such as yesterday’s. Let’s look at a sounding from the U of AZ (as displayed by IPS MeteoStar) and see what it says about those evening clouds and see if the above is just a bunch of hooey (I haven’t seen it yet, either):
The TUS sounding launched about 3:30 PM from the University of AZ campus. Suggests the cloudy air on that side of the mountains was indeed reaching to -10° C and likely a hair lower in the slightly higher cloud tops. Our tops especially a bit later and being a little northwest of there, were surely a bit colder.
Yesterday’s clouds
9:31 AM. Nice scruff of maybe Stratocumulus lenticularis topped Ms Lemmon, and indication of the lower level moistening that took place overnight with a dry front going by, with another one on the doorstep. Gee, camera lens is dirty.2:45 PM. Not much going on, just a few Cu hum, “two riders were approaching and the (cold) wind began to howl.” Bob Dylan, in “All Along the Watchtower” by Jimmi Hendrix. Nobel Laureate Bob wrote a LOT of songs about weather!2:47 PM. The Mighty Fraidy Cat Zeus, waiting for the weather to change, the Cumulus clouds to fill in. Today’s blog is particularly boring so thought I would spice it up with a [icture of a large (16.2 hands) horse that saw a tire leaning up against a horse fence, twirled around and at a full sprint, as though being chased by a Tyrannosaurus rex, plowed into a clump of tall cat claw acacias and mesquite bushes. The first second of that bolt was really exciting and fun, the second second, not so much. CMP was knocked off in the midst of them, racking up a broken rib, and a lot of scratches that bled profusely. However, with all that blood on his long sleeved shirt as he walked the mighty Zeus back to his corral, also chalked up quite a few “man points” when passersby saw him, I am sure. Well, there was one passerby who didn’t seem to notice as he drove by and I had to scream, “I’m OK! Its nothing, really!”2:48 PM. Nice lighting. I don’t know how many hundreds of these shots I have posted here. I just never get tired of sunlight and shadows on our mountains! Clouds still not doing anything, but its only been a minute since the last report.3:11 PM. Now we’re talking! Those Cumulus clouds are beginning to expand, fill in, transitioning to a Stratocumulus broken to overcast sky, a Stratocast (nomenclature unrelated to Fender guitars), as expected as the next front and trough approached. This was exciting. But when will the ice form in them to give us the first virga and precip?3:53 PM. Looking SW over the Oro Valley. This is really looking good. In situations like this, the clouds are forming as they travel upslope toward the Catalinas, and while they’re not preciping now, its fairly common in the situation we had yesterday for them to start preciping as the tops get chillier and chillier, often with the clearing remaining in place to the SW. That’s what I thought might happen. Things were changing fast at this time.5:15 PM. Virga and light precip were occurring on the horizon NW-NE, and these heavier Stratocu began to virga a few minutes after this. The anticipation? A nice period of light to moderate rain during the early nighttime hours as this deepening and filling in continued. That didn’t really happen. The clouds began to rain lightly here, but it didn’t measure. It was a another band coming through before midnight that produced the 0.08 inches.5:24 PM. I know a lot of you like to see pictures of the sun, so I thought I would post one today. Looks pretty round, a little bigger than usual. Don’t see any sunspots (defects) on it. That’s probably good.5:30 PM. Just after sundown the virga began to emit from this layer just beyond the Tortolitas. Really thought this would lead to a generous rain with continued deepening. Guess that didn’t happen. Probably only the best virga detectors among you saw this little curtains starting to descend from this cloud deck. I’ve added arrows to where those two patches of virga are.
Still looks like a chance for some light showers before the month closes out, but will be hard to get enough to bring the total to an above average value. Dang.
Will update my reader on December’s early cold outlook as new information that agrees with my assessment comes in. Right now, that information is not available.
Wasn’t going to blather about clouds and weather for a few days since there wasn’t any, just sit around and wait for those end of November storms to get here, then regale you with cloudy pictures.
But when I went to the NOAA spaghetti factory just now, I was blown away, beside myself, when I saw those outputs. Being one of the meteorological sophisticates, I suspect you’ve already trampled these maps. But, at the risk of being redundant again and again, here are a couple of jaw droppers from last night’s global data with errors input into the computer model at the beginning of the run to see how much the upper level forecasts change. There are always errors in measurements, they’re not perfect, and so by deliberately putting errors in models, we can see that range of differences in the outcomes. At first, there are virtually no differences because the errors are tiny. But over time their effect grows.
In these plots below, when the two colors of crazy lines cluster (red, representing the warmer side of the jet stream, and blue, the colder side) , it means the errors had little effect, and the forecast of a general pattern on the jet stream is one you can have great confidence in.
Below, a forecast via the “errorful ensembles” to be alliterative there for a second, in which the confidence can be quite high showing that a gigantic cold trough will sit atop most of the western US in the coming 9-12 days. Really, these are incredible:
Valid at 5 PM AST December 2nd. A massive pile of cold air is bound to be planted on top of the West with low temperatures and freezing levels by this time. Should make quite the news stories I would think when this comes around.Here’s 24 h later, at 5 PM AST, December 3rd. Look at how far the cluster of red lines is to our south, WAY down in southern Baja. Wow. The clusteriing of blue lines in the West and in Arizona suggests a very cold early December is in the bag for us. These maps also show that the SE part of the US will be nice and toasty in comparison.
So, how will it play out?
Well, we already have rather quickly passing cold troughs with their cold fronts ahead in late November, one that passes late on the 27th likely to boost our Sutherland Heights precip totals to our average value or above.
Then, the cold pattern gets amplified by this gargantuan trough that sets up a few days after those first couple of cold shots, setting the stage for cold and colder blasts. So the beginning of our cold weather and snowbirds muttering that they came to Arizona too soon, is just a few days ahead (followed by a “sucker hole” of brief temperature recovery and a few sunny days. (Well, I might be complaining, too, since cloud maven person, the writer, moved to Arizona from Seattle to be warm all day, every day. haha, sort of.)
On the other hand, there’ll be some great cloud shots in spite of the cold, and you and I, the rest of the cloud people, will both manage, warmed by the euphoria of being alive with such gorgeous scenes and exciting, changeable weather.
BTW, will close this shot-from-the-hip blog with a forecast of snow in Catalinaland in early December. That’s right, CMP is expecting measurable snow right here in Catalina.
Remember our slogan, “Right or wrong, you heard it here first!”
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.
In case you don’t believe me, here’s the model crunch from our very own Banner University of Arizona Weather Department (aka, Hydromet and Atmos Sci Dept). You can watch the storm play out hour by hour here.
The large totals of rainfall expected by mid-day this Monday, November 21st. This output based on the global data from 5 PM AST last evening. As you can see, I hope, Ms. Lemmon is supposed to get over 3 inches! Wow. How great would that be? I put some writing on this image to help you understand where you are.
However, as you can see, to throw cold water on such a great prediction, we are in the HEART of a rather narrow band of heavy precip, which raises the uncertaintly level a lot on just how much rain will actually fall. Somewhere, these days, there is a Gaussian like distribution of the rainfall at point locations so you can see just what the model spread is in the rain predictions, but I haven’t located it and am too lazy to look right now. If I come up with that, will post it.
So, just as good as that, I will say that measurable rain will fall in Catalina between Sunday evening and mid-day Monday that the least likely amount is 0.15 inches (10% chance of less), which would be a real poop, and the most, 1.00 inches (10% chance of more, a luxuriant rain, washing so much dust off stuff).
The average of those extremes is usually is closer to the actual total, which in this case would be 0.625 (correction! 0.575! Egad, dividing by 2 is still pretty hard for me) inches at my house. The idea here is that we meteorologists often know what’s NOT going to happen better than what is, in the domain of precip forecasts, and so by starting with extrema, to be erudite there for a second, we can narrow our predictions down, not get too carried away as often happens here.
BTW, if you want really great, professional level forecasting besides that by the TUS NWS , see Bob’s discussions! He’s always got great stuff.
The first high clouds ought to be arriving later this afternoon. Have cameras ready. Should be a nice sunset to go with them since there shouldn’t be a total overcast to the west.
Rain? Cumulative totals predicted here from the University of Arizona Hydro and Weather Dept. Starts overnight Sunday. For those too lazy to review the information at the link above, here is a map of the rainfall totals ending at 11 PM, November 21st:
Note that within this swath, Catalina is predicted to get over an inch of rain! Note that the swath is not very wide. A wide swath of heavy rain would be one as wide as the State. So, we have to figure that this is a lucky hit at this time, and count on something less as a virtual certainty since the swath above will move around as new model runs look at it. Typically, they shift a little east over time in those future model runs. Hope not.
Have cameras ready for a pretty sunrise. Lots of high ice clouds up there.
The weather WAY ahead
Spaghetti suggests more rain chances after a several day dry spell following the Monday rains. Check out the “pretty strong” indications that we are in the trough bowl as the month comes to an end, meaning troughs should be populating Arizona during the last days of November. In turn, good November rains, and one seems to be in the high confidence pipeline for SE Arizona as a whole, means the spring wildflowers will be given a boost. I will go on record here as now forecasting, if that’s what this is, a wetter than normal November rain total1. Our November average since 1977 is 0.96 inches.
The ensemble or spaghetti plot from the NOAA spaghetti factory from last evening’s global data.
The End.
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1This sentence will be deleted in the event of a drier than average November and will, therefore, not be on record.
