Apparently the castellanus formations went over during the nighttime hours when we couldn’t see them…
But it was a fabulous day again of interesting high and middle cloud flecks anyway. Below, a reprise of yesterday’s clouds starting with that delicate patch of Cirrus passing over the Catalina Mountains with its tiny fibers of Cirrus uncinus embedded in it. I have also included two sinister crossing contrails. Who knows what evil lurks there? Perhaps they’re marking a target of some kind, or filling out a questionnaire with crosses instead of check marks. Oh, well.
Later, as the sheet clouds of various Cirrus, Cirrostratus, and even Altostratus with virga cleared off, we got into some scattered lenticulars, some of to the distant north, and with our usual friend downwind of the Catalinas, shown in the last two shots. It was able to hang on for several hours, right past sunset.
Again, for the whole day’s cloud excitement, a great place to go is to our very own U of AZ Wildcat time lapse movie. In the late afternoon of this movie, you can see some great Altocumulus lenticularis clouds hovering over and downwind of the Catalina Mountains, occasionally shooting upwind as the air moistens in the humped up airflow, and you can get a sense of how little the air is pushed up in lenticular clouds from this movie.
(Once again the caption function has quit in WP before I got to some of these. My apologies.)
The weather ahead
Gee, “dusty cold snap” is beginning to look more like “muddy waters” as the later model runs dip the jet stream farther and farther south over us on the 14th and 15th. Check this forecast of the precip hereabouts from the U of WA’s WRF-GFS model run from last night, showing a bit of rain HERE Saturday morning (colored areas of map). Sure hope so. Terribly cold air with this, too, for mid-April. Likely some low temperature records will be set in the State somewhere for this time of year with this.
The End.
Tiny Cirrus uncinus, top center, Cirrocumulus top right with,oh, maybe Cirrus fibratus (has linear fibers) lower left.Cirrus uncinus.Altocumulus lenticularis.
Altocumulus lenticularis continues in place as sun goes down
Lots of nice Cirrus clouds yesterday, but no Altocumulus castellanus later in the day yesterday as it was asserted there would be. Only a flake or two of Altocumulus “uncastellanus”, (flat-as-you-can-get lenticular) clouds off in the distance (see bottom of page). BTW, I obsess over being right. I thought you’d want to know that about me since you come here every day and I am part of your life now. So, I made up the word “uncastellanus” because it sounds like in some way I might have been right about yesterday if you are reading quickly.
BTW#2, as per usual tendencies, the bottom of the moist layer where the Cirrus clouds were yesterday did slide down toward us during the day, from about 24 kft above the ground at 5 AM and -34 C to 21.5 kft and -27 C at 5 PM, the latter still pretty cold for clouds comprised of droplets, but they were there.
Below are a few “character of the sky” photos from yesterday. If you want the whole day, go here to the U of A time lapse. In this movie for yesterday are a few spectacular Cirrus castellanus clouds just after 11 AM AST. You’d swear they were real Cumulus clouds at first, but then you see them moving along at the same speed as the Cirrus clouds, glaciated with fall streaks beginning to come out as they go by.
You’ll also see in this movie, a lot a wind shear, changes in wind direction and or speed, with height, quite at lot visible early on. It will be easy to see how those trails of ice crystals get skewed away from the parent cloud producing these sometimes incoherent patterns when viewed from below.
Expecting castellanus TODAY, dammitall!
I think you can kind of sense my ferocity here about getting things right… A LOT of weatherpersons are like this, so its not just me.
As a potent trough blasts into Cal today, AZ will be in the rising motion part of that trough. So what happens? The air temperatures aloft begin to fall as the subsiding air pattern over us lessens and moves off to the east. With that tendency for subsiding air gone, some layers of the atmosphere will develop larger drops in temperature (lapse rate) as you go higher, a situation ripe for castellanus clouds, ones that look like miniature clouds that have been on a growth hormone. Those clouds (Ac cas) are probably my most favorite clouds, itty-bitty towering Cumulus clouds and so I do have a tendency over predict them based on a desire to see them. You can see what the TUS sounding is supposed to do here from the U of A model run. You’ll see the temperature falling just that bit over us late in the day. Well, it will be interesting to see what really happens!
Lots of other kinds of clouds are likely, too, such as a patch of Cirrocumulus, more Cirrus, and a lenticular here and there as the winds continue to increase over us. Gee, with the air coming from so far to the south, maybe even a scruff or two of small Cumulus clouds may show up, too, though Mr. Model doesn’t think so! Quite a cloud day possible.
Due to the high altitude the Altocumulus are likely to be at today, above 15, 000 feet above the ground, they’ll likely be cold enough (tops colder than -10 C, 14 F) to produce ice crystals and snowflakes, which we will see as virga coming out. Again, a fabulous sunset is possible because of the presence of more than one cloud layer.
Still only a dusty cold snap in the offing as the main upper trough bashes Cal Thursday and Friday before settling in over AZ on Saturday and Sunday.
Cirrus spissatus center (mostly).Altocumulus "uncastellanus" clouds begin to appear. I am somewhat happy since clouds composed of droplet are beginning to be present.Another Altocumulus "uncastellanus" lenticularis in the distance with Cirrus clouds.Another nice sunset, ones with mostly Cirrus spissatus (bloby Cirrus)
BTW, if you’re still interested in beer and clouds after yesterday’s blog about CIrrus being “on tap”, get this book:
Clouds in a Glass of Beer: Simple Experiments in Atmospheric Physics, Dover Publications, 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 above is one of the best you can get on how the atmo works and has been popular for decades; was updated in 2001.
I forgot about it, darn, but added it to yesterday’s blog to “go with the theme….”
Yesterday and today
Nothin’ but filmy Cirrus clouds yesterday enhancing the skies over Catalina. Here’s are two examples. BTW, if you were really noticing, they tended to be thicker and more widespread to the north, as in the second photo, closer to the main jet stream up thataway.
Same stream of moist air at high levels continues over us, but, what happens over time with these high level streams of moist air? They tend to lower in height as time goes by. Here’s the stream in this loop from the U of WA Huskies Weather Dept.
So, today, we’ll likely see some mid-level droplet clouds, not all ice clouds like Cirrus ones of yesterday, and because its relatively warm up top, those droplet clouds tend to be turreted, i. e., Altocumulus castellanus (has a base) and floccus (base is evaporating upward). Both types indicate the same thing, really, that the atmosphere is a little “unstable” up there; updrafts are easily produced when the cloud forms and a little heat is released in the condensation process.
It looks, too, like those Altocumulus clouds will be around with the Cirrus at at sunset today, and you know what that means: lots of color so charge those camera batteries, cross fingers. Could be especially spectacular.
Cal-AZ storm update
The long, and confidently predicted (think spaghetti here) and unusually strong trough and storm for April 12th is still in the cards for Cal. AZ pcpn, though plentiful for April over a couple of days in the north, may not reach us here in Catalina, and if so, will be minimal it now appears, maybe a few hundredths. Look for dusty breezes for sure after the 12th. Check this loop out for all the details, again from the Huskies.
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.
No, that’s not a baseball player that played for the Dodgers or Giants back in the 1950s, that was Dusty Roads; though Dusty Parhelia would be a nice name for a baseball player. Yesterday, with our slightly dusty skies, and on the 22 degree halo ring, and horizontally from the sun’s position, was a couple of sun dogs (parhelia) late in the day associated with those cirriform clouds we had. You know by now that those high clouds are comprised of small ice crystals. Here’s a few shots of those clouds, which were often CIrrostratus with embedded other Cirrus cloud species like spissatus, fibratus, and uncinus.
CIrrostratus fibratus with a faint 22 degree halo.The denser portions tend toward Cirrus spissatus, but several other species are also present.Faint sun dogs or parhelia located horizontally from the sun on the fainter halo
The ice crystals in those clouds are typically hexagonal (six-sided) plates, ones that fall face down. If you could be there in them, and see them falling, at eye level you would see only the sliver side of them, but if you looked down at one that went by, you would see the whole hexagonal plate. The way that they fall is why aircraft laser imagery, when the laser is oriented in the vertical, captures such beautiful, full images of plates and other flat crystals in ice clouds as the aircraft flies through them.
The sun’s white light is separated into its colored components in these hexagonal crystals (but only at certain specific angles) and for this reason, the bright spots are at the same locations relative to the sun. Since I am not an atmo optician, I am relying on the links above to provide more complete, comprehensible explanations.
Note: Caption function stopped working again in WP for the fourth photo, and after half a dozen tries, will write it here:
Photo 4 caption: An especially vivid parhelia can be seen just above the horizon at lower left. The brightest ones like this are usually associated with aircraft contrails since those have high concentrations of pristine crystals. A flying saucer, or a bird with its wings closed at the instant the photo was taken, is also visible.
Continuing….
Sat image loop from the U of WA weatherfolk show lots more cirriform clouds in route to AZ next few days with occasional breaks. So, keep your camera ready for optics and sunrise/sunset color.
The weather ahead? Dusty cold snap.
“Dusty” is kind of the word of the day today.
Long foretold big Cal storm on the 12th-13th affects southeast AZ mostly with wind and dust on the 13-14th followed by unusually cool weather for mid-April. A hint of rain excitement for Catalinians has begun to show up in model runs, such as this one from the U of WA for early Saturday morning on the 14th. Yay.
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.)
If you have had your spaghetti this morning, you would be able to write headlines like this. Here’s the plot, no, not like in a detective story, but an actual plot from the Spaghetti Factory at NOAA, valid for 192 hours from last evening, or in plain speak, next Thursday afternoon at 5 PM, April 12th, AST:
SInce you’ve had lessons in spaghetti, you should be shrieking when you see this one, “My gosh, look at that potent, powerful storm about to strike California! I can’t believe one that big would strike in the middle of April. Quite unusual.”
OK, calm down that bit, but still stay excited. Yes, the Dark Void radiating from approximately where Santa Claus lives in this plot shows you where there can great confidence that a big trough is going to be present where the Dark Void ends. Notice the dark tube extending from Nome-Anchorage, AK, all the way SSE to off northern California. And another one in eastern Canada, etc. That, as you know, is where a trough will be at 00Z on Friday, April 13th (in ordinary time, 5 PM AST on the 12th, and with that, a strong low center is coiled and ready to strike. Exciting.
Let’s go to the next chapter of this plot, one but a day later, valid for 5 PM Friday the 14th and see if the Darkness is able to extrude (I really like that word because its fun to stretch it out and make it sound like what it is describing–“ex-TRUDE”, you can feel it oozing along, its an onomatopoeia, like “thunder”). Now where was I?
Oh, yeah, the plot, revealing the plot (story-line goes), for the next day is below.
Sorry you you have to see this. After explaining the above plot, and with the background on spaghetti plots I have provided you in ealier blogs, I don’t have to tell you how disappointing the one below is. Only a slight chance of rain here exists, and there is not much confidence in configuration of the trough and jet stream around it after it rockets up to the Cal coast on the 12th.
There is another chance of rain indicated from last night’s run, that on April 19th, a day in which it has not rained in 35 years here in Catalina. Odd. Are we due? Or are there climatological factors at work to minimize rain around the middle of April? I really don’t know the answer. However, it is not a very reliable prediction at this point. It will likely come and go in the model runs in the days ahead.
In the meantime, today’s clouds
Here are a couple of shots of the Cirrus/Cirrostratus-with-contrails1 mesh we have overhead this morning, ice clouds, as you now, with a hint of lenticulars off to the distant west. Should have nice Cirrus-ee clouds all day, and again, a chance of Cirrocumulus or very high Altocumulus lenticulars. Not much chance of anything below about 15,000 feet above the ground today.
1I HATE contrails except when I am flying to some fun place I want to get to in a hurry!
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.)
On deck, this cloud stream for today, as presented by the University of Washington Huskies Weather Department. As you will see, the whole stream rotating around that low off southern California has been thickening up overnight, a process that will continue, and so it looks like it will be a frequently gray day with Altocumulus, Altostratus, and Cirrus of various types piled on top of each at times. Don’t look for much direct sunlight today. Virga (snow), too, but no rain beyond the slight chance of a sprinkle. Most of the clouds you see will be composed of ice crystals and snowflakes. Also, with the wind picking up aloft today, lenticular clouds are likely again. Look to the NE of Mt. Lem.
Don’t miss a nice sunrise shot this morning.
Yesterday’s clouds
Your approaching Cirrus/Cirrostratus deck, 1/8 inch above SW horizon at 7:13 AMIts been overcasting Cirrus/Cirrostratus (though verging on Altostratus due to some slight shading) for a coupla hours by 3:29 PM.You got yer Altocumulus lenticularis, left of the sun but not as far away. ABove that, there are some small Cirrus uncinus clouds with little trails of ice, quite delicate looking. 6:13 PMBetween dead queen palm killed by last year's historic February cold wave and the yucca stalk is Cirrus floccus trying its best to look like Altocumulus perlucidus. But its too high to be Altocumulus, and you can tell that by all the icy clouds at the same height to the right of that little cluster. 6:32 PM
Below, after you have read all the captions, yesterday afternoon’s sounding from our friends in cowboy-on-a-bucking-horse-license-plate-land which, BTW, I think is a pretty cool looking license plate since I’ve been bucked off horses myself a few times and when I see that license plate can say, quite haughtily, “been there; done that”, and tip my hat to the driver. In fact, the horse I was bucked off most recently kicked about as big as the one rendered on that WY license plate, and while I ended up in the hospital with a big bill, HELL it was worth it when you can say things like this and show that you are truly embedded in western culture, which I love after leaving the Temperate Rain Forest-Starbuck’s culture of Seattle:
What do you see in this sounding?
The pinching together of the two heavy lines (temperature to the right, dewpoint to the left) tells you the height of the moist layer in which these clouds formed.
How high was that, you ask, or not?
The “300” line (refers to millibars of pressure) is about 30,000 feet above sea level (27,000 feet above Catalina) and the top of the moist layer, about at the “200” line, is 40,000 feet above sea level, 37,000 feet above Catalina.
So, they were damn high yesterday, running between 27,000 and 37,000 feet above the ground. The bottom temperatures were about -35 C (-31 F), and the top about -63 C. What’s interesting is that lenticular cloud was almost certainly comprised of liquid water drops on its upwind edge before glaciating (turning completely to ice a short distance downstream from that upwind edge.) One of the mysteries of ice formation in clouds is that Cirrus clouds don’t generally form until the conditions for a droplet cloud have been met. This means that when ice is present, it is in a highly supersaturated environment with respect to ice and in spite of the very low temperatures, the crystals can grow and fall out producing trails or fallstreaks as you could see in the Cirrus uncinus clouds.
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.
