No, Cirrus is NOT a microbrew as you may have thought from the title and if you were visiting this site for the first time. (and to continue being juvenile from yesterday’s “Dusty Parhelia” submission because that’s who I am….)
In fact, Cirrus clouds are the exact opposite of a microbrew. Cirrus is a high CLOUD, 15,000 to 45,000 feet above ground level, lower in the Arctic or when its cold, higher in the Tropics or when its warm, like today here in Catallina. They’re composed of ice crystals with some momentary exceptions at the time of formation. To continue a theme, there are no “ice crystals” in beer; beer is also generally found at ground level.
Q. E. D.
BTW, if you’re still interested in beer and clouds, get this book:
Clouds in a Glass of Beer: Simple Experiments in Atmospheric Physics by Professor Craig Bohren. In spite of having an interest in beer or perhaps because of it, he is a Distinguished Professor Emeritus of Meteorology at Penn State University, one of the leading party schools in America. Writes about optics, too, a real atmo optician. Kidding aside, his book is one of the best you can get on how the atmo works.
To sum up, it should be another fun day of Cirrus cloud viewing for you and me. What kind will we see?
Yesterday’s clouds
Man, yesterday was great! Some unanticipated Altocumulus castellanus and floccus, middle-level clouds with little turrets, many having long fall streaks of snow (virga) rolled in during the afternoon underneath the higher Cirrus clouds, keeping the temperature down a bit. Here are some shots of what went overhead, in chronological order, in case you missed the “show.”
The show ended with dessert, another one of our gorgeous sunsets; they are particularly so when two or more cloud layers are present. In those case, you see the residual scattered light that has passed through the lower part of the atmosphere when the sun sets, turning the lower clouds gold or orange (the longer, “redder” wavelengths of light are still making it through) while the higher ones, where the sun’s light is not so scattered in passing through the atmo, are that bit lighter in color, white before this last photo. The greater the height difference in the clouds, the greater the differences in sunset colors between them. When you add shadows and highlights where the sun is striking the clouds, well, it doesn’t get any better than this. OK, I am feeling lazy now about captions; been up since 3 AM something. Can YOU name these clouds? If not, just enjoy.
While waiting for the next big thing, that big Cal storm on the 12th, one that buzzes AZ with a chance of rain a day or two later, but one that will certainly dredge up dust here (you might say that an occurrence of dust is “in the bag” with it, as it should be with this one), I will occasionally devolve into a “Stories from the Field” essay. These will involve strange, humorous, or interesting things that happened in field projects. So, here we go. You may or may not be too interested in these. If not, skip to next section about clouds well below here.
In 1972, I was loaned out in one summer from my main job in Durango, CO, one with a randomized cloud seeding experiment. I worked for a State of South Dakota cloud seeding project. That SD project, operating from May through August, was run under the aegis of the South Dakota School of Mines and Technology in Rapid City.
As a baseball player, one that continued playing long after his years of HS and JC ball, I played ball games there in Mitchell, SD, where I was stationed at a radar. I played for the newly formed, Commercial Bank baseball team. When the forecast was for no threatening weather near Mitchell, I was able to leave the radar and join my team for a game. It was the best of all possible scenarios since the games were likely to be rained out when I had to work at the radar.
Threatening weather might require launching one or more of our four Piper Twin Commanches, ones loaded with cloud seeding flares, at our Mitchell Airport site to go up and do some seeding. I was one of the several “radar meteorologists” scattered around the State that year that were charged with launching and directing aircraft around Cumulonimbus clouds that were deemed targets for seeding. Never mind what that was right now; I haven’t finished my baseball story…
One late afternoon, I was playing for the Commerical Bank team against the Woonsocket, SD, team (I did NOT make that town name up!) The “pretty good” Rich Linke was pitching for Woonsocket. It was a good, well-played game; close right to the end.
However, the forecast for “no weather” that afternoon of the game was going bad. I did not have a cell phone yet in 1972, and there was no way to reach me in Woonsocket where I was catching for that Mitchell team that afternoon.
Instead, one of our pilots, who also had a sense of humor, had an innovative thought: He (Bud Youngren) would buzz the diamond at tree top level to let me know our cloud seeding planes had been launched to go out to some hail storm farther west.
So, unbeknownst (is that still a word?) to anyone, and with a Woonsocket runner on third in the bottom of the 8th inning, and the game tied at 2-2, our Twin Commanche ROARS over the field at tree top level! You could see the rivets on that plane!
It was VERY exciting! Stunning! Jaw dropping! An incredible sight! Everyone was amazed!
The punchline. We lost the game, 3-2.
The Woonsocket runner on third base, taking note of the distraction caused by the treetop buzz and remaining calm himself apparently, scored what proved to be the winning run in the bottom of the 8th as we all looked to the sky marveling at what had just happened!
But I knew what it meant by the type of aircraft going overhead. I had to leave the game immediately to go back to the Mitchell radar I manned.
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That year, 1972, of the statewide cloud seeding project, was also the year of the devastating Rapid City flash flood that June in which up to 14 inches of rain fell in a six hour period or so. More than 220 people were killed in the ensuing flood. Up in an aircraft seeding that storm with salt (called “hygroscopic seeding”) was a School of Mines scientist, Kumud B., a genial, gentle man always with a smile. Kumud, who left the SD School of Mines later, was my officemate in a lab at the University of Washington’s Cloud and Aerosol Group for many years when I joined that group in 1976.
BTW, that type of cloud seeding, “hygroscopic”, was absolved of having any measurable effect on that devastating flash flood in the bitter lawsuits that followed1. But with such a gentle man, we practiced a form of gallows humor, “Man, I can’t believe how many people you killed!” Only with someone you, in a sense, love, can you tease like that.
However, it was an awful “joke” in retronspect, something I am guilty of from time to time, but Kumud always smiled at it. In truth, the type of seeding he was doing would NEVER have had much if any effect on such a potent storm that Nature had thrown together that day; it was organized by a potent upper level feature combined with strong, moist winds from the SE over the whole State that day, elements far beyond the control of humans or seeding. However, a seeding plane (not mine!) should never have been near it; it had been kind of a forecast bust in itself by the lead Rapid City forecaster that day.
Below, in memoriam, Kumud B., who killed all those people in 1972. (Hey, I didn’t say I wouldn’t stop kidding him. I am sure he is smiling upward from wherever he is. “I loved you, man!”)
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Yesterday’s clouds
Hmmm, kind of a sidelight now after all the above. All high clouds yesterday, Cirrocumulus (Cc) once in a while, Cirrostratus fibratus (Cs fib) at one time, and some distant lenticular clouds, Ac or Cc ones. Too far away to tell. Here are a couple of shots. In general, these kinds of clouds just tell you that there is widespread lifting going on as when a “trough” approaches; ahead of a trough (to the east) the air tends to rise gradually. If the layer (s) being lifted are patchy in moisture, or the lifting is uneven or both, you get patchy clouds. Does precip necessarily follow? Almost always in Seattle in a few hours, but here, nah.
A near perfect example of Cirrostratus fibratus (internal structure indicated in a sheet). Smooth cloud, smooth flying in it.A delicate, but VERY cold (<-35 C) Cirrocumulus mutating into Cirrus, left to far right in photo.
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1It is often the case that when people or property are injured/damaged in cloud seeding operations, that the purveyors of cloud seeding claim it had little to do with that damage or the injuries and deaths. It is only when there is no damage or deaths that cloud seeding is effective. (hahaha, a little sarcasm there.)
We had a rare form of Cirrus yesterday, whose name I have made up in the title as a hint of where they came from, due to the very high altitude and low temperatures of some Altocumulus yesterday. Those Ac morphed to Cirrus, hence the strange, unpronounceable title.
Reminder, weatherscience mavens, its more proper to say “low” temperatures; not “COLD” temperatures, FYI, though you constantly hear it. (“Things”, like coffee, air, chairs in the sun, etc., are hot, warm, cool, tepid, and cold; temperature is not a physical thing, and is high. moderate, or low, etc.))
Still bristling over some unexpected clouds yesterday, so I wanted to complain about something minor, bring some discipline to the field.
Mr. Cloud-maven person was not paying attention, asleep at the wheel, etc., when some Altocumulus castellanus and Cirrus castellanus came a truckin’ over the horizon and floated over Catalina after dawn yesterday, but had not been mentioned in this blog in advance. I am sure, since they had not mentioned from this keyboard, you may have been in some distress yesterday when they showed up and you weren’t sure what was happening. My apologies. It will almost never happen again.
Here are some photos of the interesting clouds that passed overhead yesterday. I was quite excited to see them partly because I had not prepared myself mentally for them. Now, there is something strange in the first caption. But I wrote it that way on purpose because I REALLY want to know if YOU know WHERE the HELL you are, and where the mountains are around here. Next, after that outrage, some interesting banded Cirrus. Then a hint at where those Cirrus came from in the background of the 3rd shot.
First, this sunrise over the Tortolita Mountains with Cirrostratus nebulosus (vellum-like cloud) and a hint of Cirrocumulus (tiny, brighter, flocculent specs).This banded Cirrus gave some hint as to its origin. Might be termed, Cirrus uncinus, or floccus, or fibratus, its a pretty complicated set.
Caption function not working now for this third shot in WP, so here it is:
3) A nice example of Cirrus uncinus in the foreground, tufted or hooked ice clouds trailing tiny ice crystals. In the background, a clue to the origin of the patchy, banded Cirrus.
4) Another shot of the approaching Altocumulus castellanus (Ac cas) and (Ac floc) floccus clouds as they arrived overhead, some of which have morphed completely into ice (Cirrus) clouds, such as that larger element over the house in the foreground! In the upper left quadrant of this shot are Ac clouds that, to this eyeball, are still liquid.
Droplet clouds have more sharply defined edges because droplet clouds have MUCH higher concentrations of particles in them than ice crystal clouds (which tend to make them “fuzzy”, ghost-like, striated, fibrous, etc.
Why this visual difference, which I want you to learn, to see for yourself and impress your friends?
There are more cloud droplet condensation nuclei than there are ice crystal nuclei. For example, liquid Altocumulus clouds might have 100,000 to 500,ooo drops per liter in them, while ice crystal clouds may have only tens to a few thousand per liter (and then only in newly formed elements) of ice crystals. In general, there are more cloud condensation nuclei than ice nuclei, too.
Today
While “Joe” is spinning up into his little hurricane-like self in some kind of weather tantrum off the California coast today before heading to Oregon, our skies over Catalina will be marked by various forms of Cirrus clouds, ice clouds well above 25,000 feet above the ground, and not much else. BTW, you can follow Joe’s progress here from the U of WA, if interested.
If you’re interested, instead, of following our Cirrus clouds as they approach and go overhead today, go here, also from the U of WA. You see the Cirrus clouds pealing off the main frontal band in the Pac NW and then fading as they head this way. (I would increase the speed of the loop for maxium excitement.)
Now that your camera battery is fully charged, you will be ready for the panoply of high and some mid-level clouds that will be arriving overhead today. Should make for some great sunrise and sunset shots, but also daytime shots due to the interesting twists and turns in the Cirrus (ice) clouds that will float by. Maybe later today, Cirrocumulus and Altocumulus clouds will show up adding that extra dimension to sunset color. Typically, in these situations, the first clouds on the scene are Cirrus at the highest levels (30,000 to 500,000 thousand feet above ground level (hahaha-just checking to see if you are reading this)–OK, 30,000 to FORTY,000 feet above the ground here on a warm day in Catalina-Tucson like today.
Next, with the moisture layer thickening downward from those high CIrrus levels as the day goes by, there might well be some Cirrocumulus (Cc) cloud patches, ones between about 15,000 and 25,000 feet above ground level. Some times they evolve to Cirrus clouds within minutes after they form when they’re colder than -30 C (-22 F). Cirrocumulus are short-lived clouds usually in thin, isolated patches. They can have no shading by definition and they can display the most delicate granulations imaginable.
But those patterns change in seconds to a few minutes, and you have to have your camera by your side to get the best shots of that sort of thing, like other nature photographers who shoot birds and stuff like that. Did you realize that by shooting clouds that you were becoming a “nature photographer”? Often these patches can be higher level lenticular clouds (thin sliver clouds) that have smooth portions on the upwind side and then break into tiny elements downstream.
Finally, as the day comes to a close, some Altocumulus clouds might arrive on the scene; if not today, then by tomorrow at daybreak. They may also be in the form of sliver clouds, lenticulars that hover downwind of mountains–look to the northeast of Mt. Sara Lemmon today. But, given the high temperatures aloft, indicating that the Altocumulus clouds will have more water in them than on a cold day, look for some sprouts and little turrets. That extra warmth, say at 15,000 feet, results in an enhance updraft when clouds form at those levels because condensation releases a small amount heat to the atmosphere inside the clouds. That bit of extra heat is likely to lead to those itty bitty turrets (castellanus species of Ac)
Here is an example of the delicate Cirrocumulus (Cc) clouds we may see today and tomorrow.
No rain seen in models for two weeks now, but remember the wild chaos of the predictions beyond six days now, as indicated in “spaghetti plots.” That means rain for southern AZ may well show up again soon, along with that horrific early April cold spell.
Yep, that’s right, rain IS imminent! In case you forgot what they looked like, there’ll be a display of “hydrometeors” before 7 AM here in Catalina. Should last the whole morning at least. If you don’t believe me and think I just made this up, go here.
BTW, “hydrometeors”; what real meteorologists, well, maybe pretentious ones, call rain drops; remember, we’re METEORologists, we like to see things falling out of the sky.
Not raining now at 4:38 AM, but its on the radar here for the Catalina area from a great weather provider, Weather Underground. Amounts here likely to be around an inch in the next 48 hours. Still looking for a drop in temperature enough to bring our current (5: 1o AM) mid-fifties temperatures into the upper 30s in the rain as the cold front goes by, maybe tomorrow morning as well as a second little pulse of clouds and precip keeps things going for a second day. That temperature drop should lead to a little snow in the heavier periods of rain.
Second pulse?
Racing from the north central Pacific is a little blob of clouds down the “backside” of our humongus trough. Here, from the University of Washington Huskies, still playing basketball in the NIT tournament, is a 500 millibar map. The blob of clouds that will extend our rainy spell is located, on this map, a few hundred miles west of San Francisco. It is CRITICAL to us to get that second day of showers after the current front goes by with its strong rainband today.
The green lines on this map are contours along which the wind blows. Here you can see a HUGE fetch from the north central Pacific to Oracle Road, Catalina. To demonstrate this more clearly, click on the map below to get the full version, and place a finger on one of the green lines in the north central Pacific, say, just south of the Aleutians. You might want to pick the one labeled, “5580”. Then with your finger on that line, follow it southeastward (“down” toward the lower right), maintaining contact with the montior screen, until you exit the right hand side of the map. I hope you haven’t had a peanut butter and jelly sandwich before doing this.
If this map pattern was stationary, that’s where the wind would go, forever, “down” and then “up”. Where your finger reached the point farthest to the south on this map, and where the wind makes a sharp turn around San Diego, is what we call a “trough”. And, if you were to see a map at a LEVEL in the atmosphere, there would be a long extension of lower pressure from the Pacific Northwest to San Diego at the time of this map. But no, we meteorologists complicate things by using constant pressure surfaces which go up and down in height all over the map instead of constant level surfaces instead of an easy to understand constant level map with highs and lows on it. Oh, well.
This “second pulse” of clouds and precip is moving so fast, it will get to the “bottom” (south end where the wind curves to the north) of the trough before it has a chance to exit Arizona. That will add a whole second day of showers and rain with a very low freezing level tomorrow. Its a bit rare to see something like that catch up so fast to the main trough and, in a sense, delay its passage.
Yesterday’s clouds
Okay, you had yer flying saucer clouds here and there during the day, that is, in proper cloudspeak, Cirrocumulus (Cc) lenticularis (first photo), Altocumulus lenticularis (second photo, is lower, has shading, compared to Cc–that short flat cloud below the Altostratus layer), you had yer Altostratus band (3), followed by yer clear slot, beginning at 4 PM -hope you planned a picnic around it, or trip to the beach (4), then quickly followed by heavy, dense Altostratus layer, (see second shot with saucer cloud).
No sunset color due to the solid cloud banks to the west. Should be enough breaks in “post frontal” low clouds for sunset color today, however.
It was zero visibility in Parhrump, Nevada, yesterday afternoon with wind gusts to 85 mph, as the cold front was about to crash on by. I guess we were lucky to only have 40-50 mph puffs of wind here in Catalinaland overnight, and not so much dust (yet). A sharp, but dry cold front is bearing down on us, but the low center that was so intense yesterday over Nevada, then moved across Utah, has faded trying to move through the Rockies. This means that the winds will be much less than yesterday.
Does that mean no dust around Catalina today? Nope. Those strong winds in Nevada and western Arizona yesterday raised a lot of fine (as in tiny) dust particles that are likely to be suspended for a day or two, and so we’ll likely see dusty skies today, without so much wind anyway.
We had some nice Altocumulus/Cirrocumulus lenticular clouds in the afternoon yesterday. I wonder if you saw them? They weren’t around for long. Here’s what they looked like.
The last shot is of a cigar-shaped flying saucer with multicolored lights, OR, a Cirrocumulus lenticularis showing some slight iridescence (which are those rainbow colors near the edges of the cloud due to diffraction). You have to look very hard to detect coloration in this cloud shot, but its there. Diffraction is the bending of sun’s white light as it passes around the tiny (micron-sized) drops in the cloud and that leads to a separation of the white light into its components of reddish, greenish, blueish colors.
Take yer choice on what was photographed, but it is true that clouds such as lenticulars have been reported as flying saucers that “hover” then disappear. This cloud was completely gone in one to two minutes after this photo AND was stationary, as lenticulars are in the face of strong winds aloft and at the ground, which also influences the observer’s reports of unexplained “hovering.” This little cloud had been much larger ten minutes before reaching this size.
You can probably understand why such reporting might happen when you look at how smooth this little lenticular was. And sometimes, when nearer the sun’s position, the colors caused by diffraction are quite vivid.
Wildfire smoke
Also, in the late afternoon some smoke from the Nogales wildfire headed our way. It gave a great example of what young smoke looks like, that is, smoke recently emitted from a fire nearby. Its always got lots of gradations of the smoke in it because it hasn’t been around long enough for turbulence to mix out the smoke into a homogenous layer. This happens when smoke has been around for days and days and has traveled thousands of miles, and so its one way of telling that a smoke layer has come from a long distance.
Sometimes high, smooth, long-range transport smoke layers can be mistaken for Cirrostratus, hold yer hat, “nebulosus”, a completely smooth ice cloud without much internal detail. Below, the smoke from the Nogales area as it headed northward toward Catalina.
Rain possible?
It seems as dry as this system is, about all we can hope for is a trace.
It does appear that there will be enough moisture by tonight and for a couple of days as this cold air over us hangs around that we will see high-based (that is, probably based at or above the top of Mt. Lemmon) Cumulus and Stratocumulus clouds, and with the low temperatures aloft, ice should be able to form in them–which as you know, means virga, snow falling out and melting on the way down.
However, it would appear that only sprinkles are possible at ground level here in Catalina.
What to do?
You won’t want to miss entering the fact that a sprinkle occurred in your weather journal, one that might only last a minute or two, and so its best if you keep, say, your car parked outside where a layer of dust can accumulate, and then, when the rain drops fall, they will leave impressions in the dust.
The full moon of last evening, FYI.
Factoid: it is thought that the moon was originally part of the earth, the result of a gigantic (!!!) impact that sent part of the earth out into space which then became our moon. This theory would explain the synchronization of the moon’s face with the earth, that is, having the same face toward the earth. Hmmm. Hope we don’t have another one of those soon. Two moons would be mind boggling.
Like an errant bowling ball (you remember bowling, don’t you?), the models are now pretty much in agreement that instead a “strike”, or at least a “spare”, or even a few “pins” being knocked down here in Catalina, by our approaching, spinning “ball” of low pressure, it is now foreseen to end up as a “gutter ball”, bypassing the “lane” entirely and heading off to to coast of southern Mexico, the way the Canadian forecast model had been saying all along. The US model had rain here for days on end, and it passed much closer to us. But not now. Below is the latest awful depiction from IPS Meteostar if you haven’t seen it yourself, one valid for Wednesday evening at 11 PM AST:
This is one of the worst forecast maps I have ever seen. You can see where the low ends up, over Cabo!
I felt I had to prepare you mentally since no models I can find out there have any rain here with that system now. And there is no rain seen in the next 15 days in the US WRF-GFS model, either! So La Nina!
This is an odd configuration down there off Mexico, too. This is normally the dry season in central and southern Mexico, so some Mazatlanians and Puerto Vallartans are going to get quite the winter surprise down there in a couple of days. It would be fun to go down there and see the surprise on the faces of vacationers and locals when this thing hits, to see, really how weather impacts people. As a meteorologist, I feel much more important when important weather strikes. People want to talk to you then and ask things; “How long is this going to last?” “Have you ever seen this happen before?” You’re really kind of the focal point of everyone’s life then. You’ve probably noticed how excited TEEVEE weather presenters get when weather is the lead in the news, with that kind of haughty smile, or pretending to be sad, because a hurricane just hit, or six feet of snow fell somewhere.
But when important weather hits, they become the stars of the news programs, and maybe “stars” for a couple of days! Yes, that’s what we weathermen and women like, odd weather, NOT normal weather where we have to think of “happy talk” and jokes and things to say to our fellow anchors instead of talking about something important. I have to say I am a part of that weather culture, too. But with no storm at hand, I will not be so important to my friends today1.
Yesterday’s iridescent clouds, in case you missed them
Iridescent clouds are ones with especially tiny droplets that produce rainbow colors because the light is diffracted around the drops, and in doing so the white light from the sun is broken up into into its various wavelengths and colors that go with them (reddish, longer wavelengths, bluish, shorter wavelengths. For a nice explanation and spectacular examples, go here. Yesterday’s iridescence appeared yesterday in newly formed Cirrocumulus clouds.
Revealing personal note——————————————————————————————————————————————————————————————————————————————————————-1This whole “storm-now-missing-us” thing and loss of importance reminds, too, of John Denver, and when he died in that plane crash. In those days before that happened, people used to say I looked like John Denver or thought I was John Denver, strangers even, and maybe I cultivated that look to make myself seem more important than I really was. It was great having a stranger want to talk to me, often a woman as it turned out. But then when John Denver died, I was sad, not for John or anything like that, though I did like some of his songs, but because I knew I pretty soon people would not ask me if I was John Denver and want my autograph, as happened in a Durango, Colorado, supermarket where I lived. I was pretty bummed out back then, really, and that’s the way I feel about this “gutter ball” thing today. Below, me as “John Denver.” BTW, mom liked to be “Marilyn Monroe” so that she would seem more important, so this is kind of a family culture we Rangnos have to boost our self-esteems. It really helps when you’re only a weatherman or other ordinary person to be somebody famous! There was a guy just last night at the Fox Theatre here in Tucson pretending to be former Beatle, John Lennon! I’ll bet he felt great because it was just like John Lennon actually being there!
Just a couple of photos of yesterday morning’s glorious display of Cirrus (OK, “uncinus”) clouds, those high, icy white ones that were so fantastic enhanncing the desert and Catalina mountain background, taken from on top of a horse.
As you know by now, those Cirrus clouds are composed of tiny ice crystals, but, as tiny as they are, they are generally far larger than droplets in clouds. So, when ice clouds form, they are essentially precipitating clouds. Those ice crystals are too heavy to stay aloft and the larger ones settle out producing these extremely fine, delicate strands. Sometimes those trails extend thousands of feet below the “head” of the cloud where they were generated, and as they fall, go into regions where the wind is slightly different in velocity and direction, and so you get interesting twists and turns.
If you could fly up there, you would find tiny snowstorms of simple ice crystals shaped like little bullets (a crystal type), triangular prisms, stubby columns, or plates, crystals that would sparkle as they went buy and showed their pristine faces to the sun. Seen’em do that many times when with the U of WA and their flight research program. They look like daytime shooting stars, or fairy dust, as they rush by the pilot’s window, and also where I was, viewing from a dome atop the fuselage of our various aircraft. You would not know you were in a “cloud” except for those displays.
The last photo is of a droplet cloud, Cirrocumulus, composed of extra tiny cloudlets. It was a higher altitude one, pretty cold up there, maybe -30 C. Went off the “screen” before it may have crystalized into a Cirrus cloud many do. I thought it was a nice view, taken on the Canyon Loop Trail near Green Rock yesterday.
First of all, let me assure quesy readers that the jet leaving the contrail at left was not “flaming out” and about to crash as it traversed the sky at this time, as the staccato nature of the contrail at left might suggest. The staccato nature of the contrail is due to vagaries of humidity at flight level. Where it was quite dry, the contrail disappeared immediately behind the jet.
Its a little unusual to see such short segments like this, however.
What was really interesting and a bit inexplicable (again) except via a LOT of hand-waving is the crossing patterns seen in the clouds at left and in the next shot. Pretty darn remarkable. In the second photo, icy strands of cirrus (“fibratus”-the strands are straight in this variety) are seen running SE-NW, “whilst” above there are Cirrocumulus clouds with ripples and little cloudlets oriented from SW-NE! All of these clouds were moving rapidly from the SW.
Maybe its too complicated; we should forget about it and go to the movies. Well, the cloud movies…
First, if you take the time to load this time lapse movie, you will enjoy the tiny cloud “tumbleweed” that goes by at 12:02 PM. It really acts like one, as you will see! Its an entertaining sight, and one that illustrates the wind shear in the atmosphere yesterday.
And that’s what these remarkable crossing cloud configurations are about, changes in wind direction and speed with height, something we “met men” call “wind shear.”
Some of the clouds in the second photo passed within the viewing area of the U of A time lapse movie between 1:59 and 2:03 PM LST and you can just make out the cirrus clouds going by with their lower portions draining off to the right very slowly. In these blog photos, looking as those clouds approached from the SW, the trails appear to originate on the right and “drain” to the left, a mirror image.
Ice crystals in cirrus clouds often form in sudden appearing, tiny flocculent specs like the Cirrocumulus (Cc) clouds. In these photos, in these photos, the Cc clouds are above the icy cirrus clouds. What normally takes place is that the ice crystals grow and the largest ones fall out producing strands below the “head” of the cloud. The slower they fall, the more apt the fallstreak is to be drawn out over a long distance away from where the burst of ice formation took place, and if there is a sharp wind shear, the more angled and contorted the trail will look. Still, at right angles? The Tucson sounding for yesterday afternoon doesn’t reveal much wind shear in the moist layer where these clouds were forming, 23, 000 to 27,000 feet above sea level. On the other hand, balloon soundings would not show extremely sharp changes in wind direction/speed over very small height increments. So, it remains somewhat of a mystery. In view of the orientation along the jet airway upwind of this site that runs in the direction of the line cirrus in these photos, it is possible that these are contrail remnants. There jets that flew at low enough altitudes at times to glaciate some of the Cc-Altocumulus clouds and one short ice trail produced by an aircraft in them can been seen in the U of A movie at 2:43 PM.
Along with these interesting alignments were numerous optical phenomena yesterday, some of which I could not identify, such as in these three. I suspect the first one is something called a parhelic circle, if you happened to have seen this bright arc radiating away from the sun’s position. A bit more mysterious, at least to me, was the sudden brightening of the contrail segment above the Catalinas and the cirrus (uncinus) cloud, last two photos.
OK, enough. I tried my best to explain everything and I have failed.
But first, “storm” 3 of six as foretold many days ago by our wonderful numerical models having “billions and billions and billions” of calculations (to use a numeric phrase made popular by the late Carl Sagan) is going to pass over today. Hoping for a sprinkle late in the day, but virga seems likely in the Altocumulus clouds that will develop/move in today.
The jet stream is powerful over us from the southwest, and when you have these weaker disturbances with marginal moisture, you can get some glorious, fine granulations in the clouds (Cirrocumulus to be exact) as we saw two days ago. See photo below. So, I am expecting to see the following types of clouds today: Altocumulus with virga, some clusters large enough to produce a sprinkle even at the ground (see second photo from two days ago with “mammatus”-see footnote below and virga), Cirrocumulus, and some cirrus. Could be a fabulous sunset with these kinds of clouds around.
OK, so “storm” 3 today may be just a few clouds without any precip. Oh, well.
Cold and unusual snow occurrences ahead for the West and for Cat Land, too
The low pressure center and accompanying Arctic blast now developing in the Pacific Northwest will be historic. What I mean is the that climate record books will be altered for things like late snow occurrences, one of the lastest snow occurrences (as in Seattle), latest lowest temperatures, all time February low temperatures, and unusual flurries and brief snow accumulations at anytime in places in California. This is a whopper of an atmospheric ice berg from the ground all the way up through the troposphere in the West as it progresses down the West Coast. Snowfall at SEA LEVEL is likely all the way down to….Los Angeles suburbs.
Then after shuttling down the coast, this “ice berg” takes a sharp right turn (as seen from the weather maps), that is, toward the east and to Arizona! Egad. Not only will it be unusually cold again, though nowwhere near the “historic” cold wave early this February when all kinds of low temperature records and pipes were busted, though another hard freeze does seem in the cards after the rain/snow/wind pass by. Monday and Tuesday mornings look awful darn cold right now.
Did I mention wind? Along with this situation will be an unusually strong low pressure center that will give us the kind of blustery day this Saturday as we had last Saturday with gust to 50 mph here on the Catalina Rise just west of the Cat Mountains. So, if you’ve got dried out, stiff palm fronds you’ll probably lose a few more in this one.
Did I mention snow? Its now looking like a greater chance for a small accumulation of snow as low as 3,000 feet here on the west side of the Catalinas on Sunday morning. I’m not buying skis just yet, but this is a real interesting situation.
And, finally, it looks like an appreciable rain, too, with this, maybe more than half an inch between later Saturday and Sunday night. Man, will this be welcomed around here!
Since I am overly excited about this interesting weather pattern that is on our doorstep, it should be noted that objectivity is in decline… At the Unviersity of Washington we had a forecaster who loved snowstorms. And so, when he saw a snowstorm coming and forecast an amount, say 10 inches, you had to divide that forecast by 100 to get the most snow that could possibly fall from that storm.
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Footnote: On the fifth floor of the Atmospherics Science Building at the University of Washington, there was a line of large cloud photos on the wall, one of which was a “Cumulonimbus mammatus” that strongly resembled the “mammatus” in the second photo below. The photo caption to that effect was vandalized, and we suspect by a female meteorologist/grad student who might have taken exception to this traditional, formal descriptor established decades ago. The word “mammatus” was crossed out and replaced by “testicularis.” It was horrible thing to see.
