6:52 AM. Altocumulus cloudlets over and east of the Catalinas.6:52 AM. Sprinting to the other side of the house, this spectacular scene of virga falling from Altostratus. Breathtaking!6:53 AM. To the NW, the virga roiled downward into mammatus bulges under lit by the sun.6:54 AM. The color was fading just in a minute or two, but it was still a breathtaking panorama I thought you should see.
Some additional commentary about these scenes. One of the remarkable things about clouds, a real unknown, is how clouds such as Altocumulus (1st photo) can get so cold, colder than it was this mid-November in Wyoming, and can remain all or mostly water drops, which is what you are looking at in those cloudlets over and beyond the Catalinas. Pretty amazing. This phenomenon has been known about for decades, but not fully explained. We expect to see a lot of ice in clouds with tops colder than -30 C (-22 F) as you might imagine.
Here’s the sounding near the time of these photos, with writing on it:
———-Begin learning module———————————-
The Tucson balloon sounding, launched around 3:30 AM AST yesterday morning.
As a CMJ, you need to be armed with explanations if, on a morning walk, your neighbor, at first overwhelmed by the morning beauty, but then instead of being quiet, goes on to ask, “Hey, aren’t those clouds composed of droplets; they must be pretty low and warm?”
Since you’ve already seen the TUS sounding for the hours just before this, you know those cloud bottoms are real cold and high, -26 C, and 19,000 feet above you here in Catalina, and tops are really cold, about -32 C (-26 F), you cringe. What to say? How do you explain clouds that can sit there at -32 C and develop little or no ice, while knowing that Cumulus clouds, ones whose tops have never been colder than -7 C, can be completely composed of ice just after reaching up to that temperature?
—————-End of learning module, such as it was———————
Here’s another example from yesterday of extremely cold clouds with few ice crystals:
9:36 AM. Altocumulus perlucidus opacus (sun’s position is not detectable). The TUS sounding for the morning would not be valid at this time since the cloud bases were slowly lowering but they would still be about -20 C at this time, height about 17,000 feet above ground level. And, at this temperature, such clouds are ultraripe for ice production by aircraft that may flay threw them. See next photo for a POSSIBLE aircraft production of ice in these cold clouds.
10:43 AM. Of course, all of you were looking for some aircraft perturbation I’m sure, and this seemed “too linear, too uniform, the crystals too small (as deduced by the sloping lines of virga underneath this line for the ice to be natural. No other virga looked like this having straight fine lines underneath, the thing typical of contrails. However, its not the typical ice canal, either, with clearings beginning on the sides. In fact, the cloud seems thicker here where an aircraft may have traversed it, posing an explanatory challenge. Also counter to reason, why would an aircraft fly so far in what would have been light rime icing conditions in those Altocumulus clouds? Lots of questions, no really good answers.
11:07 AM. Linear feature passes over Catalinaland. Was hoping for a drop so I could claim it had rained in November, even if it had been a phony rain.
11:32 AM. Looks phony to me! Not a real cloud. I think we’re looking now at the tube of high concentrations tiny ice crystals that slowly settled out from that Altocumulus layer after an aircraft went through it–this tube to me appears to be BELOW the general layer, due to settling out after a few larger ice crystals fell out first. Am about 60 % sure that’s what happened and caused that linear feature. Getting pretty worked up about, too.
Well, Shakespeare said it: “Much ado about nothing,” so it must be important if he said it.
Had some really nice cloud scenes after the big clearing came through in mid-afternoon:
3:38 PM. Our typical spectacular lighting on the Catalinas scenes as storms move away.
4:49 PM. A dramatic finish to the day; light showers hit south and southwest of Tucson, but faded before arriving here.
There were some light showers that produced as much as 0.20 inches of rain in the south and east parts of Tucson late yesterday afternoon and evening. Nice for them.
The weather way ahead
Nothing in the way of rain in the immediate future. Have to wait until December for any real chances. See this bad boy for December 6-7th, this panel only 360 h from now1!
Valid at 11 PM AST December 6th. Note that the heaviest rain in Arizona is over Catalina! These are totals that accumulated in the 12 h prior to 11 PM AST. Hope I made you that bit happier showing you this. It’s a pretty cold system, too, might be a close call for snow here.
The End.
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1360 h in advance, even using our best model, is about in time like the distance to Betelgeuse in light years. Hence, caution when the writer says, “only.”
6:55 AM. A surnrise glow from receding CIrrus spissatus highlights Samaniego Ridge. Very pretty and dramatic.
8:19 AM. Forming uncinus, CIrrus that is. Note trails of precip beginnng to form under these tufts of Cirrus castellanus clouds.9:06 AM. Jet contrails begin to show up in a Cirrocumulus cloud composed of supercooled cloud droplets. You know what going to happen….something special for you to log in your cloud diary.
9:20 AM. Another patch of supercooled, very supercooled for that matter, Cirrocumulus with evidence of a jet contrail. But, is the jet above or IN the Cirrocu? TIme will tell.
How cold were those Cc clouds? See below.
(Begin technical module)
The Tucson balloon sounding1 for 5 AM AST, November 19th with writing on it. The height of these clouds was slightly lower in the mid-afternoon, but (as Altomumulus then) were still about -23 C. As we know, cloud bottoms almost always get lower with passing time because the higher parts of cloud shields are moving faster.
In the mid- -20s C, around -15 F. Height, about 21,000 feet above the ground here in Catalina. Hope you got that estimate of cloud height right.
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Continuing…
9:21 AM. ANOTHER jet streaks by! This is going to be darn interesting, a rarity, like seeing a grey parrot in Catalina! The secret about what height the first jet was flying at is beginning to be revealed. Can you see what’s happening to that first contrail a little below the new one? This is a great test to see how far you’ve come as a CMJ (cloud maven junior)!
Here’s what happened in the Cirrocumulus cloud layer in yesterday’s special day, a pretty rare one, after the jets flew through it:
9:30 AM. OK, mystery’s over. Even the average CMJ Joe can see that 1) the jets were IN the Cirrocumulus cloud, and more importantly, the aircraft contrails consist of ice. Yes, that’s right, the passage of the aircraft has caused a phase change from liquid drops to ice crystals, a lot of them.
9:47 AM. Now those contrails are looking like real and icy Cirrus clouds. In this case they’re called “ice canals” but sometimes, when aircraft are ascending or descending and do this, they make round clear holes with ice in the middle, called “hole punch” clouds.
Lessons to be learned from yesterday’s supercooled clouds and the aircraft interactions inside them:
Cloud seeding works! You CAN make a supercooled, non-precipitating cloud produce a little precipitation that would not otherwise have occurred.
But in those situations where the clouds, say, are topping the Catalinas, they are often quite thin, and whether there is an economically worthwhile amount of precip is not known. However, an experiment targeting those clouds would be the perfect “baseline” one in cloud seeding to establish how much we can wring out of non-precipitating clouds. Things become kind of a mess when even randomized seeding takes on already precipitating clouds.
“Overseeding”, as here in these clouds when aircraft produce prolific numbers of ice crystals in a small volume, it leads to tiny ice crystals with low fallspeeds. Sure, they fall out and leave a hole, but they virtually never reach the ground except in one a in billion cases when the very cold clouds are real low, practically on the ground.
The Wegener-Bergeron-Findeisen mechanism produces precipitation.
Alfred Wegener, 1911, and later Bergeron3 and Findeisen in the 1930s, came up with the hypothesis that adding ice to a supercooled cloud results in the growth of the ice crystal at the expense of the droplets. They’ll tend to evaporate while ice is being added to the crystal via deposition of water vapor that was once liquid. So, an awful lot, maybe most of the precipitation that falls on earth, involves “mixed phase” clouds. This process has also been called the “cold rain process.”
However, let us not forget the two other processes that produce precipitation, the all ice process (no liquid required–helps produce “powder snow”, and the all liquid process, where cloud drops collide and grow into raindrops–the biggest measured drops in the world (about 1 cm in diameter) have formed soley through this process. It is likely that most of the rain that falls in tropical locations like the Hawaiian Islands and in hurricanes is due to this process even when ice is present in the top part of storms.
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Later, we had some Altocumulus castellanus clouds with virga as the moist level lowered, though they were long gone before they could provide us with a nice sunset:
2:32 PM Bands of Altocumulus castellanus approach Oro Valley from the west. These clouds, while based at just about the same level as the Cirrocumulus clouds earlier in the day had three things going for them to produce so much ice (right side of photo–and really, convert to Cirrus clouds). The cloud bases were slightly warmer (the TUS sounding suggests, -22 C), meaning more water was available to the cloud, something that would impact the drop sizes in the turrets of the Altocumulus clouds (left side of photo); 2) the tops were higher than the Cc clouds (ones that were paper thin) and therefore, slightly colder (probably about -28 C) than those of the Cc clouds, and perhaps as importantly, the drops near the top of the Ac turrets before they converted to ice, were larger than those in the earlier Cc clouds. The larger the droplets, the higher the temperature at which they freeze. So, ice is more likely to form in a cloud with larger droplets in it than one with tiny droplets in it even though they are the same temperature. That might explain the difference ice-forming behavior of yesterday’s very thin Cc clouds which mostly had no ice (until an aircraft came along in them) and these prolific ice-producing Altocumulus clouds, ones that converted to all ice. Just educated guesses here.
Still looking for scattered very light showers in the vicinity tomorrow as a Mr. Troughy goes by.
The End.
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1Through the oral history tradition I learned while viewing the Washington Husky meltdown2 at AZ stadium on Saturday from a Mr. Mark Albright that the Tucson weather balloon launch site has been moved from Davis-Monthan Airbase to the University of Arizona campus next to their weather department.
2Late in the proceedings, with about 2 min left and the Huskies starting a play, and in the lead, CM was visibly moved to jump up and say, “Don’t hand the ball off!”, as a gift to Arizona fumble occurred simultaneously. But, being bifurcated in his loyalties now that CM is in Arizona and not with the University of Washington, he had to be somewhat “glad” that the Cats maintained their somewhat suspect but great win-loss record.
3From the Historic Moments in Weather collection:
Your Catalina CM and Tor Bergeron meet for the first time in Goleta, CA, in 1968 at the headquarters of North American Weather Consultants. Yours for $2,100 dollars, today only. I remember thinking that his head was gigantic! No wonder he was so smart. CM, not so much.
Here we go…..some pretty, but also dull, photos, along with some novella-sized captions as mind wandered into the obtuse while writing them.
6:44 AM. Nice sunrise due to Altostratus/Cirrus ice clouds.2:00 PM. Kind of a dull day yesterday, kind of like this blog. Stratocumulus (Sc) clouds topped Samaniego Ridge most of the day, below that gray Altostratus ice cloud layer. But those Sc clouds were too warm to have ice in them, and droplets were too small to collide, stick together, and form misty drizzle. Have to get to at least 30 microns in diameter before they stick to one another. Misty drizzle? Could be a great name for a late night female vocalist doing earthy songs like Earthy Kitt back in the ’50s. “Earthy” was much hotter than global warming.3:29 PM. An Altostratus translucidus to opacus, mostly ice-cloud with a dark patch of Altocumulus droplet cloud blocking the sun. If you look closely, (upper center) you can see a that there’s this Altotratus layer may be topped by a Altocumulus perlucidus droplet cloud layer. Yes, droplet clouds at the top of As where the temperature is lowest? Yep, this counter-intuitive finding happens all the time, up to about -30 C -35 C. Been there, measured that; in aircraft research. Ma Nature likes to form a drop and have it freeze before forming an ice crystal directly from the water vapor.4:40 PM, shot taken as we entered a local restaurant. You’ve got your two layers of Altocumulus, with some Altostratus translucidus above those, filling in the gaps. Gaps? Huh. I am reminded that I have a failed manuscript about “gaps”, these kind; Cloud Seeding and the Journal Barriers to Faulty Claims: Closing the Gaps., rejected by the Bull. Amer. Meteor. Soc. way back in ’99. It was an instruction manual, in a sense, about how to prevent all the bogus cloud seeding literature that got published in the 1960s through 1980s, and was not only published, but cited by our highest national panels and experts, like the National Academy of Sciences. Amazing, but true. I give examples. You can read about this chapter of science in Cotton and Pielke, 2007, “Human Impacts on Weather and Climate”, Cambridge U. Press, a highly recommended book. That cloud seeding distortion of cloud seeding science was due to many factors, of which perhaps the primary one was, “nobody ever got a job saying cloud seeding doesn’t work1.” This was a great segue. Of course, we have similar stresses on those researchers looking for effects of global warming nee “climate change” now days. Nobody will ever get a job (a renewed grant) saying they can’t find evidence of global warming, “Can I have some more of that money to keep looking?” And beware the “Ides of March” if you criticize published work in that domain! Think of poor Judy C , a heroine to me, and how she’s been vilified for questioning climate things.
5:29 PM, took leave from Indian food there in R Vistoso for this. Its not just anyone who would excuse himself from dinner to do something other than visit the laboratory.
That’s about it. No use talking about the rain ahead again. Seems to be a couple chances between the 20th and the 30th.
The End
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1You can make a cloud snow a little by seeding it with dry ice or silver iodide. This has been shown since the earliest days of experiments. Below, to demonstrate this, an aircraft inadvertently “seeded” this Altocumulus cloud layer. However, whether the small amount that falls out from previously non-precipitating clouds is economically viable is not known. Increasing precipitation due to seeding when the clouds are already snowing/raining has not been satisfactorily proven. As prize-winning stat man, Jerzy Neyman, U of Cal Berkeley Golden Bears Stat Lab would tell you, you need a randomized experiment and followed by a second one that confirms the original results, with measurements made by those who have no idea what days are seeded and evaluations done by those who have no vested interest in cloud seeding. Wow there’s a lot of boring information here. Getting a little worked up here, too.
Ice canal in supercooled Altocumulus clouds over Seattle, bases -23 C, tops -25 C (from PIREPS). Photo by the Arthur.
A measly 0.01 inches is all we got here yesterday in a Seattle-like rain from an overcast that sputtered drops drown over a couple of hours, one that could barely wet the pavement, if we had any here in Sutherland Heights. Of course, we surely drooled at the close call that drained Saddlebrooke yesterday afternoon (see below). Probably washed more golf balls into the CDO wash like that storm did last year…
Also, 0.75 inches fell, too, where Ina crosses the CDO wash yesterday, “so close, and yet so far away”, as the song says. Oh, well, another missed rain that I have to crybaby about1. Will get some final pictures of the 2014 summer greening today before it fades away in the many dry days ahead to help make me feel better now that its over.
Here’s your cloud story for yesterday. It was pretty neat one, full of hope, even if that hope was eventually dissipated unless you lived in Saddlebrooke… The U of AZ time lapse film for yesterday is great, btw.
6:31 AM. I am going to say these are Altocumulus castellanus clouds, though they are a little low and large for that genera.
6:33 AM. This was a pretty scene… Here an isolated Ac cas rises up. Distant small Cumulonimbus clouds, weak ones, can be seen on the horizon.
9:18 AM. Before long, those pretty Cumulus clouds were springing to life off the Catalina Mountains, the sky so blue behind them.
9:19 AM. A rare “High Temperature Contrail” (HTC) slices through some very thin Altocumulus perlucidus. This aircraft phenomenon has also been called, “APIPs” for Aircraft Produced Ice Particles.) Recall that Appleman (1953) said that an aircraft couldn’t produce a contrail at temperature above about -35 C. But, he was WRONG. They can do it in a water-saturated environment at much higher temperatures, even as high as -8 C (see Rangno and Hobbs 1983, J. Clim. and Appl. Meteor., available through the Amer. Meteor. Soc. for free, an open journal kind of thing.)11:48 AM. Before noon, all thoughts of past glory were gone as the Big Boys arose in a hurry. What a dump here! The cloud, since it is not showing an anvil nor obvious fibrous appearance, still pretty cauliflowery even though the discerning CMJ would not be fooled by its icy composition, it would be a Cumulonimbus calvus (“bald”).3:40 PM. Probably THE most hopeful scene of the day. A large complex of Cumulonimbus clouds was emerging from the Tucson mountains, heading in this direction. But more importantly, were the cloud bases forming over Oro Valley ahead of it, likely, it seemed to be pushed upward by the outflowing winds ahead of the distant cells. Also, that cloud bases were forming and extending westward from the distant cells offered another rain-filled scenario that could happen as they approached from the SW.
4:14 PM. When the southwest wind arrived, it did in fact cause the clouds overhead to swell up like aphids on a Seattle rose bush, but as bad luck would have it, they were piling up just to the north of us and over Saddlebrooke where they all all those amenities and don’t really need a lot of rain.
4:40 PM. After the first base dropped its load a little beyond Saddlebrooke, another cloud base darkened and expanded over Saddlebrooke, but this time, began to unload there. Here, like the seldom seen pileus cloud, these strands of the largest drops being to pour out of the collapsing updraft. You have about two minutes to see this happen because if you look away, the next time you look there will be nothing but the “black shaft.”
4:45 PM. A remarkable transformation. How can so much water, you wonder, be up there in a cloud?
6:05 PM. As the threat of any significant rain faded away, there was at least some “lighting” excitement, produced for just seconds as the sun shone on this….Stratus fractus cloud. Again, you must be watching at all times to catch these little highlights.
6:58 PM. Time to say goodbye to Cumulus and Cumulonimbus clouds like these, until maybe next summer.
The End. Probably will go on a hiatus now.
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1Its good to remember that there is a little crybaby in all of us, isn’t there?
Probably haven’t heard that name in a while. It kind of went along with “Old St. Nick”, “Jack Frost”, the kind of thing that we kids called things.
Well, yesterday in the land of Catalina, we had three separate thunderstorms in about 8 h, all producing nearly continuous thunder, and when you could see it, nearly continuous lightning. Oddly, there were few cloud-to-ground strokes. The lightning, too, was odd, light bulbs going off in small areas of the thundering clouds, and when visible, was a fine, often curly cue thread, seemingly one third the width of “normal” lightning. Thunder was heard at 6 PM, 11 PM, and 1 AM1 in those separate storms. Was a pretty fantastic light show, as you know, since you likely got up to watch it as I did.
All in all, while not a lot of rain fell in Catalina (one core over the Golder Ranch Bridge at Lago del Oro Parkway, presented the gauge there last night with 0.43 inches, though friend, Rick Bowers of Bowers Photo over there on Trotter said he got 0.65 inches, the most in town. Here in the Heights, just 0.24 inches. Still, its ALL good, except maybe for the flying ant swarms that are beginning to erupt.
Here’s the quickest way to look at some rainfall numbers around the region: Pima County ALERT gauges. And here fro the State, from WSI Intellicast’s rendering of radar-derived precip, usually pretty accurate.
The best way to reprise your cloud day, to make sure you logged all of them in your cloud diary, is here, courtesy of the fine University of Arizona Department of Atmospheric Meteorology time lapse film. It was so good yesterday, I put in two links to the same thing. Really is a complicated flow day, one cloud maven person has not seen before.
To wit, there were two layers of ice clouds traveling almost perpendicular to one another. Never saw that before. The height difference must have been huge. You will also notice some Altocumulus tufts at the SAME level as that
Big fat contrail leads to a “heavy” fall of ice crystals at about 9:30 AM, the aircraft flying in the lower ice clouds (where it was warmer, of course, and that means the ice content was higher than in the Cirrus clouds way up top that moved from the west). That higher amount of moisture allowed bigger ice crystals to form and fall out so obviously from the contrail.
And it was an extraordinary event for another reason: contrails aren’t supposed to form at the temperature this one did! You won’t find contrails forming at -20 to -30 C in Appleman’s famous nomogram for contrail formation. No, that’s right, you’re not supposed to get them until about -35 to -40! Could be a publication in this….
IN FACT, what happened is related to the “Hole Punch” and “Ice Canal” phenomenon2 resulting more often from aircraft flying through droplet clouds like Altocumulus, ones that are also very cold, usually colder than -15 C. So, the ground has been tread pretty heavily in this domain EXCEPT that there was NO DROPLET cloud where that strongly precipitating contrail was laid down! Could be a publication, to repeat…some “sci glory” might be down the road….)
Here’s the Tucson sounding that tells all:
The balloon sounding for Tucson yesterday morning, valid at 5 AM AST. Note reversal of winds (west at 40,000 feet or so), then from the east at 25,000 feet or so (above sea level).
Well, got WAY behind in chores following the “vacation” in WA and OR lately, so will quit here. Instead of a cloud shot, I will leave you with this public service reminder about dumping in others trash bins.
Putting stuff in other people’s dumpsters can lead to financial ruin. Don’t believe me? Read the bottom lines (see below).You’ll need a second mortgage to pay the fine! And, why don’t they just make it a million dollars…
More thundershowers on the way here as the Pac NW goes into a heat wave over the next few days. Heat? Hah! They know nothing about HEAT. If its 85 F, they think its really hot!
Forecasting tip: in the summer when the Pac NW gets hot, we’re usually wet. So, lots of great days ahead, and more visits by “Tom Thunder.”
The End.
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1Weren’t we supposed to drink Dr. Pepper at these times?
2Mr Cloud Maven person, yours truly, had his feelings hurt when his paper about his own research aircraft producing ice in clouds at below freezing temperatures, co-authored with Peter V. Hobbs, was rejected twice, but then accepted on the third try (way back in the early 1980s) and in the end, everybody was happy. You can read the whole story here. It starts out, so you can see how bad I felt, “…the reviewers are still unconvinced by these controversial claims.”
6:05 AM. Pretty ripples in Cirrocumulus below some Cirrus. What a fantastic and subtle scene this herring bone pattern was!9:34 AM. Pretty much a whole Cirrocumulus morning, punctuated by a few Cirrus clouds. Why isn’t it Altocumulus? Granulation is too tiny; no shading. BTW, no ice evident though this layer was colder than -20 C (-4 F).10:30 AM. An aircraft has punched this very thin Cirrocumulus layer and left a tell-tale ice trail that looks like natural Cirrus. Same cause for that second, white ice patch farther to the west. Its almost impossible to detect something like this since the ice trail from the aircraft is almost exactly in the form of a Cirrus uncinus. The absence of natural Cirrus is a clue about what happened.10:34 AM. The aircraft-induced Cirrus is passing overhead, and if you look VERY closely you can see that tiny “supercooled” cloudlets of Cirrocumulus are still there around it. The ice crystals fell below the Cc layer and disappeared over the next 15 minutes.2:27 PM. Later that day….widespread natural Cirrus overspread the sky, with a very thin patch of Altocumulus on the right (granulation is a bit to large for Cc).3:44 PM. Those Cirrus clouds thickened and lowered some, trending (as we would say today) toward Altostratus (translucidus–the thin version).
Today’s clouds
Today our passing cold-core trough is overhead and in the middle of it, the moisture is low enough to trigger Cumulus and small Cumulonimbus clouds as the middle and high clouds exit “stage right.” Should be an interesting day since these cumuliform clouds will be so high-based (above the Lemmon summit) and cold that lots of ice will form, producing virga, and in some places, sprinkles. A hundredth or two is possible, but that’s about it. Heck, I guess there could be some lightning here in southern Arizona as well.
This will be the last interesting cloud day for awhile, as you likely know.
Below, your weather map for 5 PM AST when there should be plenty of ice action all around:
I’m talking about your clouds and weather day yesterday, and definitely NOT about someone whom I shall call, “Sharon1“, that happened to me 33 years ago and whose birthday was yesterday, Ground Hog Day, a day commemorated by a 1993 movie about a weatherman. Seemed “right”, too, to be a weatherman with a girlfriend whose birthday was on Ground Hog Day. I loved her so much! Was definitely in the first stage of the psychologist’s lab standard, the Passionate Love Scale2 ; euphoric when things were going right, and also a stage characterized by delusional and obsessive thinking. (Haven’t we all been there at some point?) Had a great sense of humor and playfulness about her, too. As it turned out, though, I wasn’t good enough for her. (I really wasn’t; she was a med student and all that; very brainy, so there was quite a mental contrast.)
Oh, yeah, NOW for the clouds yesterday on a cool day which is what I was talking about to being with; high only 55 F here in the “Heights”:
6:06 PM. Altostratus, of course, with slight virga consisting of very light snow. Too thick to be Cirrus. 3:18 PM. Altocumulus perlucidus. What the temperature? In the middle of the photo there’s an ice canal–hoped you logged it in your weather diary. That ice canal was caused by an aircraft passing through a cloud that’s well below freezing. The exact reason for the sudden freezing of drops in that cloud is still being investigated. However, when you see this phenomenon, an ice canal or hole punch cloud, I want you to FIRST think of ME, because our paper on this phenomenon was rejected twice back in the early 1980s before being published, and second, when you see this happen, estimate that the droplet cloud was probably at -20 C (-4 F) or colder. Yes, THAT cold and still composed of droplets! Therefore it produces a buildup of ice on an aircraft when one flies through it, but then the aircraft changes that by converting to ice behind it! How strance is that?. (I deliberately misspelled “strange” to see if anyone has read this far.)
Annotated version. 3:19 PM. Frosty the Lemmon. Good sign of rime icing on those trees up there. You see how frosty they look? Likely because of supercooled cloud droplets hitting the trees and freezing during all the low clouds of the previous day. Very pretty. 2:19 PM. “Angel’s hair”, Cirrus fibratus. The delicateness of those striations are amazing when you think that they are traveling in air moving at around 80 mph up there around 30-odd thousand feet above us.
Below, the predicted total rain in Arizona as this great trough goes by. NIL in Catalina! The map below is a forecast of all the rain areas and their amounts expected by 2 PM AST tomorrow afternoon. Fortunately, it has been, as in basketball, “rejected.” Read details in caption.
Expect a trace to maybe a tenth. No drop will escape my attention!
The End. I hope you’re happy now since I have titillated you with a personal story in a cheap attempt to raise blog ratings. Haven’t broke into the top 10 million blogs yet. But maybe if min is more like “Entertainment Tonight”, I make that breakthrough.
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BTW, if you haven’t heard yet: “Seattle Celebrate (sic) SB Win!”, a title and article written by a possible drunken AP writer after the SB, if you’re interested.
————– 1Defintely NOT a picture of “Sharon”, but its how she MIGHT have looked had she been in my Seattle living room with her son, New Year’s Eve, 1981. And, of course, I found someone I loved just as much later…
2Don’t believe me that such a thing exists? Read the first column of SCI CLIPPINGS CAUDATE OVER HEELS IN LOVE 001, no less. Probably goes farther in its discussion of these kinds of things than we really want to know about and how they came to know them…be advised.
WHAT a gorgeous day was yesterday! Perfect. No wonder the northlanders come here in their droves now! Its great to see (via the increasingly larger number of out-of-state license plates) all the people that want to be where I am already!
While waiting for the storms and cold air just ahead now, this cloud commentary:
Along with the pretty high and middle clouds was a rarely seen phenomenon, aircraft flying into those “supercooled” Altocumulus droplet clouds were converting them to ice in their wakes. These are similar to contrails, called by me, APIPs, Aircraft Produced Ice Particles. That’s right, your Catalina Cloud Maven person named that phenomenon, though its not a great name since it could apply to usual contrails as well. Modest brain strained hard, but couldn’t come up with anything better. So, given that background, he’s probably going to make a big deal out them when he sees one or two here.
Its rare because the Altocumulus have to be pretty cold, -15 C (5 F) or so and colder1, and at a level where aircraft are flying, usually in a descent or climb pattern to their normal flight altitudes up around the higher Cirrus levels (30-40 kft above sea level and at temperature generally below -35 C). Typically because of climbing or descending, the ice canals, or holes with icy centers, are short and small. Here are a few examples from yesterday, but you really want to look at the U of AZ timelapse movie to see a bunch of them going by in those pretty Altocumulus clouds and mackerel skies we had. Note that as cold as these Altocumulus clouds were, they were not producing ice:
12:21 PM. Ice strip produced earlier by an aircraft that flew through supercooled Altocumulus clouds. Usually these events lead to optical displays like this faint sun dog almost overhead. You have about 10 seconds to see it, but, of course, Mr. Cloud Maven person, on a hike with friends, was waiting for it to happen.
11:21 AM. One of many.12:19 PM.11:50 AM. Note Cirrus-ee part upper right.
And there were other fine sights! Look at this display of Altocumulus perlucidus undulatus, rippled mackerel sky:
11:12 AM.1:19 PM during hike with friends, not just people standing there as I walked by, in case you thought someone who would write like this and take cloud pictures all day might be a recluse and have no real friends. Shown are Bill and George, JoAnn and Vollie, admiring the Cirrostratus shield coming over the horizon. (I do see why you might think that, though.)4:42 PM. Day ended up with a great big halo; haloes are pretty rare here in the kinds of Cirrus clouds we get. More Altocumulus out there, too.
Weathering ahead….
Looks like cold spell will last, once underway, into the middle of the month. SNOW indicated HERE in Catalina-land on the morning of December 11th from a crazy model run based on last evening’s global obs at 5 PM AST yesterday. Here’s what that morning looks like overhead, at 500 millibars:
Valid at 5 AM AST December 11th. Thinking about making snowballs that morning. Also, in appeal to youthful readers, I have texted some here. Astonishingly deep cold air piles into Arizona, Those northlanders will be piling into their jeeps and heading home. Unfortunately, an examination of the reliability via the newly named, “Lorenz plots” from NOAA, show virtually no support for this “solution.” It appears, at least for the moment, dang, as a crazy outlier, likely due to some goofy error (s) WAY upstream somewhere. But, its fun to contemplate snowballs here in Catalina.
BTW, the local weather services all around the SW are already worked up over the coming cold wave and have issued Special Statements, quite fun to read because they reflect the excitement we weather folk are feeling now as we look ahead to wind some rain, and a big frontal passage followed by cold air. After all, the weather’s pretty dull here in SE AZy most days of the year, and by “dull” I mean that not much is happening except for pretty clouds and nice temperatures, a weatherperson’s “dull.”
The End.
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1 Yesterday afternoon’s Tucson balloon sounding which I forgot to look at until now:
Rawinsonde balloon sounding data from Tucson. Balloon launched around 3:30 PM local yesterday; rises at about 1,000 feet a minute.
Here is the temperature change from yesterday morning at this time to today at this time, courtesy of The Weather Channel and due to that dry cool front that went through yesterday. Its about 8 degrees cooler this morning here in Catalina compared to yesterday at this same time. Nice.
But, its back to above normal temperatures for a few days after this respite. Normal is around 90-92 F here in Catalina for this time of year, but a 100 F is just ahead I’m afraid. No rain seen in mods for the next 15 days, too. Feeling glum.
Yesterday’s clouds
Had some nice supercooled Altocumulus translucidus clouds yesterday after the Cirrus departed. Here’s a shot that was taken as an aircraft flew through a patch of it. Note fine contrail. These clouds, from the Tucson sounding at 5 AM AST, appear to have been at temperatures between -15 and -20 C, ripe for aircraft to produce icy canals or holes, and that’s what happened. Below is the rest of the sequence, taken from different locations. In the last shot, the tip of that icy contrail began to light up and I thought I might see some color due to refracting ice crystals, but it didn’t happen. These aircraft effects on supercooled clouds are receiving more attention in the scientific community, BTW.
For a time, too, we had our lenticular cloud friend downstream of the Catalina Mountains in its normal position.
Powerful, but dry system progged for later next week
Check this “four panel” out, bottom of blog, from the Canadians from their model run last night. Its valid for the afternoon of Thursday, May 24th at 5 PM AST.
My first thoughts: Egad! Holy Smokes!
Looks like low temperature records will be broken in the West and Pac Northwest as this comes through those areas. However, the thought of the ovenly air over the Southwest at this same time, being drawn into the western High Plains States was alarming. This is because it could get superhot over there as our hot air comes down out of the Rockies. Fortunately, the models don’t show the 120 F temperatures in the Plains my alarmist mind was generating.
What WE will get here in Catalina as this giant trough settles in the West for several days is a LOT of wind and dust in a lot of hot air before the cooler air arrives sometime after May 25th.
This period of wind and hot air will be awful for the fire situation. No rain is indicated with this giant low, too.
I dread these days because you’re thinking about how much is on the line as far as our forests go.
Trying to feel better today about the huge miss, that “gutter ball” low that is slipping down the Baja coast toward MMZT (“Mazatlan” in weather identifier jargon) right now as I write, and trying to forget about what it could have been. Reminds me, too, of that critical dropped pass in the Superbowl by some guy in the last 40 seconds that could have changed the game, or that girlfriend who found out I was older than she thought and I went off the relationship possibility radar after that, etc. From the University of Washington, to sigh about, this map series for 500 millibars . Its good to sigh about things, shows you’re alive inside, have feelings that get crushed every so often. Hahahaha, sort of.
You will see that the winds at 500 millibars (18,000 feet ASL or so) around the Baja low are stronger on the back side (the green lines are closer together on the west side compared to the east side). Therefore, to paraphrase, “Don’t need no model” to know that this low going to head SE and away from us. Maybe it’ll reach the Galapagos Islands….dammitall.
As the low moves farther and farther away, the gradual ascent of air that produces all those clouds you see drifting up toward us from the south, weakens. The rain lessens, too, the clouds begin to thin and lift above the ground as they move into AZ. That’s what happens in these situations. That upper low needs to stay close for the clouds to remain thick be rain producers here.
So, even though the clouds look great on the satellite images, and are producing rain to the south of us here in Catalina, and are heading this way, they end up thinning and weakening as they do. Expect to see a lot of virga today from heavy Altostratus opacus clouds (mostly deep ice clouds), and that’s about it. But even a sprinkle would be nice, just to remind us again that it can still rain here.
Rain in the future?
Here is is, THREE chances the mods now say after having nothing just yesterday at this time. Two minimal events have shown up; one on the Sunday the 12th and again on the 14th, THEN this behemoth of a storm on the 23-24th, shown below! I am beside myself with excitement dreaming about how important I might be to my friends a couple of days before it hits! Though we know, by now, that what is shown below is as likely to be realized as an ice crystal forming in HELL, nevertheless, it is HOPE. Check it this out from IPS Meteorstar’s rendering of our US WRF-GOOFUS (“goofus” after about a week in advance) model and be happy! “Totally awesome!”
“In case you missed it” department; yesterday’s aircraft effects on Altocumulus clouds
The temperature of those “supercooled” clouds was around -20 C, perfect for aircraft to make holes and ice canals in them, a kind of inadvertent cloud seeding. Here are a couple of shots, the first, a hole with an ice patch in the middle, 2) and ice canal, and three strange optics caused by aircraft-produced ice crystals.
Enjoy, or be upset by artifact ice.
Hawaiian Storm and Big Wave Alert
Continuing the theme about meteorologists and the excitement we get over bad storms, a weather student at the University of Washington was beside himself and sent an e-mail to all of us on the weather list, in case the rest of us missed it, this NWS bad storm news for the Hawaiian Islands and giant surf. Seemed kind of funny, this extra effort to bring to our attention a really bad situation there. I do have to admit wanting to go see the waves crashing on the rocks and world class surfers who will come in their droves to surf’em. I had to smile reading this:
“Check out the front page of www.weather.gov right now – the unusual front Greg Hakim mentioned at the end of weather discussion today is the top story, above the map. If it’s changed by the time you’re reading this, here’s the message:
…Threat of Coastal Inundation for the Hawaiian Islands and the Marshall Islands…
Published: Tue, 07 Feb 2012 19:27:29 EST
High Surf Warnings are in effect for Hawaii, where the 10 to 20 foot waves observed today are expected to rise to 18-35 feet tonight. High tides and strong winds are expected to impact the Hawaiian Islands as a cold front moves across the area. This will increase the potential for coastal inundation, with potential impacts including road over-wash, sand or rocks on the roadways, and water approaching exposed property areas. The Marshall Islands have the potential to be similarly impacted. Details…”
