Ice optics – Cloud-maven

Phenomenological extravaganza

First you had the rarely seen “Aircraft Produced Ice Particles” (APIPs, or “High Temperature Aircraft Contrails” (HTACs) in supercooled Altocumulus in the afternoon. Contrails were being produced in clouds that were “only” -20 C to -30 C (-4 to -22 F) and aircraft contrails were thought to be impossible at those temperatures, but rather, only at much lower ones, below -40 C (-40 F) or so.

Then, just after sunset, the heavy layer of Altocumulus produced a sun pillar! I was out in Saddlebrooke having dinner with friends after sunset, so had to leave dinner for about ten minutes, but I was so excited for you that I had to see it for myself, too. Since it would have been obscenely rude to tell my dinner friends the true reason why I left, when I got back after many minutes I told them I had to pee, and that seemed to go over pretty well I thought¹.

Below, a coupla shots of that sun pillar I got while “peeing” on your behalf:

5:33 PM Gently falling pristine² hexagonal plate ice crystals, falling face down from mostly supercooled Altocumulus clouds, produce a sun pillar. This site says that sun pillars are typically seen with Cirrostratus clouds and I have not photographed ONE due to Cirrostratus clouds myself, but rather ones like this falling from……yes, that’s right, Altocumulus clouds having just a bit of ice in them. How funny is that?

5:33 PM. Closer look as it fades. Note the small liquid water mammatus bubbles upper right. Mammatus in liquid clouds is also pretty rare since they are downward moving puffs of air and droplets evaporate much faster than do ice crystals. Mammatus is nearly always restricted to ice clouds for this reason. Was also wondering if my oversize salad and hamburger had been served yet.

Let us look at our sounding and see if we can see how cold those Altocumulus clouds were:

Tucson sounding launched from our U of AZ around 3:30 PM yesterday. The arrows denote the likely heights and temperatures of the Altocumulus we saw, somewhere around -20 C or -30 C or both. — Tucson sounding launched from our U of AZ around 3:30 PM yesterday. The arrows denote the likely heights and temperatures of the Altocumulus we saw, somewhere around -20 C (-4 F) or -30 C (-22 F) for both. Hard to tell which layer was the one the aircraft were flying in, but the colder the supercooled cloud the denser the ice trail. So…..since they were dense yesterday, CM is going with the one at -30 C. Yes, that’s right, liquid droplet clouds can exist at -30 C, full reasons not known, but indicates a lack of ice-forming particles up there. But, it can also happen at the ground, too, in fogs.

Here are some of the magical, rare scenes from aircraft making ice canals in those very cold supercooled Altocumulus clouds:

2:25 PM. Ice canal over Boot Barn. — 2:25 PM. Ice canal over Boot Barn down there on Oracle somewhere.

2:29 PM. Contrail castellanus? Had never seen anything quite like this before. Going crzy over sky phenomena now. — 2:29 PM. Contrail castellanus (that row above the pole)? Had never seen anything quite like this before. Going crazy over sky phenomena now. Word Press, as here, is corrupting some of these images; can’t fix it so far.

3:51 PM. Just above corrupted part of this file–I’ve given up trying to fix it in WP, is an aircraft streaking through this Cirrocumulus/Altocumulus deck, and an ice trail will form. How can you tell that that aircraft is IN the cloud and not above it? Look for different movement between the contrail and the cloud. If they are moving together, its usually the case that the aircraft was in the cloud. The aircraft is in the cloud at left.

3:51 PM Close up. Very excited that a trail would develop. You almost never see the aircraft leaving the trail like this; you see the trail after the aircraft is long gone.

Skipping to the chase, as hard as that is to do, this trail really lit up as it got to the 22 degree point from the sun, where mock suns and such happen, producing a rainbow of colors due to iridescence, a rainbow producing by very tiny ice crystals in this case, of the order of a few microns in size.

3:55 PM. Started to glow a little orange here.

3:55 PM. Was turning brighter colors as the seconds went by. Unfortunately, this image is again corrupted when bringing it into WP. — 3:55 PM. Close up of the feature event. Was turning brighter colors as the seconds went by

Still 3:55 PM. Going from orange to blueish.

STLL 3:55 PM. Color fades into white as this icy contrail in the Altocumulus raced eastward. More WP corruption here, too. Think I’ll quit! Just too much time to do this to have this kind of crap happen! Sorry, having little baby tantrum now.

Guess about today’s clouds

Maybe a few Cirrus, patch or two of Cirrocumulus, and likely lenticular clouds, particularly off to the north.

The End

The big storm everyone’s talking about?

Oh, yeah, baby, its still comin’, begins on Wednesday, New Year’s Eve in the afternoon, continues for about 24 h off and on.

Bracketing possible precip totals: still 0.25 inches on the bottom (10% chance of less), 1.50 inches on the top (10% chance of more). Average of those two often brings the best estimate, which would be about 0.87 inches, somewhere in there. You know, when you deal with wobbly cut off lows, you just can’t be real confident in how much rain they’ll bring. However, it looks like the north part of the State will get the brunt in snow, which will be great for the water situation.

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¹It would be fun to hear what your excuses were as a “CMJ”–Cloud Maven Junior, if you were in a similar predicament last evening and HAD to see that rare sun pillar, rather than meet new people at dinner who wouldn’t be able to understand you anyway because you are compulsed like that; leave a great dinner to go outside in cold air to take cloud photos.

Well, nobody really understands a CM.

I remember in grammar school and Junior High in Reseda, CA, when kids teased me on clear days , saying, “Hey, Artie! Is it gonna rain today?” Then they would laugh at me for being a CM before I even answered the question, knowing all the while what the answer was going to be. Still, out of civility, I would answer them: “No, we’re having Santa Ana conditions now and it can’t rain for at least five days”, but they would still be laughing in the midst of my explanation about why it wasn’t going to rain. Kind of a sad scene when you think about it, that is, how mean kids can be to kids who are different. Later, when I became a pretty good athlete, they liked me, which shows how important athletics is over knowing stuff, and helping you “fit in.”

²“Pristine” means that can’t be gunked up by having collected cloud droplets on their faces because then the optics, like sun pillars, mock suns, that kind of thing can’t happen if the crystals are messed up with droplets on them or a lot of extra hexagonal arms sticking out of them, as in bullet rosette ice crystals.

Pretty cloud day yesterday; storms dead ahead and ahead

In case you missed the pretty sights of yesterday:

7:05 AM. Sunrise on the Altocumulus. Two layers are evident.

8:42 AM. Kind of blasé except for the rarely-seen-in-AZ (faint) halo. Altocumulus with Cirrostratus above.

3:30 PM. Pretty patterns; Altocumulus perlucidus.

4:45 PM. Cirrus uncinus and Altocumulus (clouds with shading). — 4:45 PM. Cirrus fibratus (not hooked or tufted at top) and Altocumulus (droplet clouds at right with darker shading). Lower gray portions beyond Pusch Ridge and extending to the horizon is probably best termed Altostratus.

4:56 PM. Nice lighting effects on Samaniego Ridge. — 4:56 PM. Nice lighting on Samaniego Ridge.

5:21 PM. Your sunset. Nice underlit virga from patchy ice clouds. Could be termed Cirrus spissatus or Altostratus, if you care. — 5:21 PM. Your sunset. Nice underlit virga (light snow fallout, likely single ice crystals, not flakes) from patchy ice clouds. Could be termed Cirrus spissatus or Altostratus, if you care. What kind of crystals, you ask or didn’t? Bullet rosettes.

The clouds and weather just ahead

Expect more Altocumulus, Cirrus, and Altostratus today, patchy and gorgeous. Would expect some nice Ac castellanus (one with spires) as an upper level low off Baja starts to move toward us. Some measurable rain likely tomorrow in the area, but probably barely measurable, maybe a tenth at most since it will fall from middle clouds with a lot of dry air underneath them. (Enviro Can mod still sees rain around here tomorrow.)

Middle clouds might get large enough to call the (small) Cumulonimbus clouds, with a slight chance of lightning tomorrow, Thursday, as this low moves up and over us.

So both today and tomorrow will have some great clouds!

WAY ahead; watch out!

After a quiescent period of gorgeous, misleading days, where the temperatures gradually recover to normal values and you’re gloating over the nice weather you’re experiencing by coming to Arizona from Michigan, blammo, the whole thing caves in with strong storms and very cold air heading this way. Yesterday’s 18 Z WRF-GOOFUS model run for 500 millibars (rendered by IPS MeteoStar), was, if you like HEAVY precipitation throughout Arizona, well, truly”orgasmic.” You just cannot have a better map at 500 mb for Arizona than this one from that run. That low center over California, should this verify, would be filled with extremely cold air from the ground on up, cold enough that snow in Catalina would be expected as it goes by. So, there’s even a prospect of a white Christmas holiday season. Imagine.

Valid 264 h from 11 AM AST yesterday morning, or for 11 AM AST, Saturday, beginning of football bowl season I think, which last until February I think. — Valid 264 h from 11 AM AST yesterday morning, or for 11 AM AST, Saturday, beginning of football bowl season, which last until February I think.

Now will this verify exactly like this? Nope, not a chance. But, spaghetti tells us we’re going to be in the Trough Bowl, filled with cold air and passing storms beginning in 8-10 days from now. How much precip and how cold exactly it gets is unknown because these progs will flop around in positioning the troughs that head our way. There will be major troughs passing through, so while the amount of precip is questionable, the cold air intrusion is not. It was just so neat, exciting, mind-blowing to see that such a gargantuan storm has been put on the table for us in that 18 Z run.

Most likely subsequent model runs will take this exact map away, but then put something like it back, until we get much closer to verification day, the 21st. May even shift around on which day is the doozy, too, by a couple of days either side. Still, a really exciting period of weather is ahead.

This may seem odd, but one of the keys to our storms way ahead is the eruption of a huge storm in the western Pacific (and that storm is shown developing in the last day (144 h panel) of the Enviro Can mod.

———–dense reading below————-

That erupting, giant low pressure center will shoot gigantic amounts of warm air from the tropical ocean far to the north ahead of it in the central Pacific. That warm air shooting north, in turn, causes a bugle to the north in the jet stream, a ridge, which deflects the jet toward the north toward the Arctic. As the jet stream does that, there is almost an immediate response downstream from the ridge; the jet stream begins to turn to the south, developing a bigger an bigger bulge, or trough to the south. So, a jet stream running on a straight west to east path across the Pacific can be totally discombobulated when a giant storm at the surface arises and shoots heat in the form of clouds and warm air northward¹. In this case, all of this takes place beginning in the Pacific in about 6 days, so that a sudden southward bulge, a buckling of the jet stream, due to that giant low in the western Pacific 8, 000 miles away, happens over the western US. And voila, our big cold and maybe our big storms, too. then.

————end of lead-filled text———

The End.

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¹First noted by much-honored meteorologist, Jerome Namias, who did not have the Ph. D. but was great anyway, in the early 1950s.

Airplanes slice through clouds; leave icy canals and trails

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 sun dog almost overhead. You have about 10 seconds to see it, but of course, Mr. Cloud Maven person was waiting for it to happen. — 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.

11:50 AM. Note Cirrus-ee part upper right.

And there were other fine sights! Look at this display of Altocumulus perlucidus undulatus, rippled mackerel sky:

1:19 PM during hike with friends, not just people standing there, 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 Vollie, George and JoAnn, who are admiring the Cirrostratus shield coming over the horizon. — 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, rises at about 1,000 feet a minute. — Rawinsonde balloon sounding data from Tucson. Balloon launched around 3:30 PM local yesterday; rises at about 1,000 feet a minute.

Upper trough with rain continues to march toward Catalina from Siberia and points west

…and maybe points north, too. Lately models have been foretelling rain in Catalina on the 17th or 18th. In case you don’t believe me, here’s the precip forecast from last evening’s (00 Zulu) WRF-GOOFUS¹ model run for the morning of the 18th as rendered by IPS MeteoStar:

Valid for Monday morning at 5 AM November 18th. The colored areas are those in which the model has foretold rain during the previous 12 h. As usual, the heaviest amount is foretold for my house here in Catalina/Sutherland Heights.

What are the chances this will really happen so many days ahead? Pretty good. Let’s check out the “Lorenz map²” below:

The Lorenz map valid for 5 AM, Monday, November 18th. Cold air? Its in the bag. Rain? No doubt showers in the area with a pretty low snow level. — The Lorenz map, a name I made up but he deserves it since he came up with the Chaos Theory due to which such maps like these are produced by our computer models; where little, itty bitty things can feed into the system and alter the whole thing, like the cliche of a butterfly flapping its wings in Brazil and affecting a tornado in Texas later, as a friend said in a SEA Times article a few years ago, a friend, BTW, that I played softball with on the Dept team and could really hit the long ball³… Oops, where was I? Oh, yeah, this map is valid for 5 AM, Monday, November 18th.

Cold air in Catalina? Having to put your jacket on for a few days? Its in the bag.

Rain? No doubt showers in the area with a pretty low snow level on the 17th-18th, but, with the long overland trajectory as presently indicated, not much, maybe a tenth of an inch or so, kind of marginal.

Yesterday’s clouds, high ones

There was some iridescence in a patch of Cirrocumulus about mid-morning, and then what might have been a bit of a parhelic circle in a patch Cirrus. That was it. More interesting clouds today as streamers of moist air at high levels sporadically invade Arizona, and today should be one of those. Get cameras ready!

: 10:56 AM. Sublte bright, slightly curved line in the upper part of this photo of a Cirrus cloud patch may have been a “parhelic arc.”

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¹ As the Global Forecast System is affectionately known.

²I think E. N. Lorenz deserves it, a map with his name on it that we currently call “spaghetti plots”, or by the uppity “model ensembles” name. You put little errors in at the beginning of the model run and see how different the end results are. Not too much effect at the beginning because the errors are so small, but usually end up producing a ball of yarn after kitty played with it, as one reader wrote, after a couple of weeks, meaning that the reliability of any specific prediction at that time is nil. You see, all instrumentation has some error factor, so we never really measure the exact state of the atmosphere. This is a technique of adding little errors is to see how much they can affect the outcome. Sometimes, when something really POWERFUL is out there somewhere, those little errors don’t have much of an effect, and that’s when we can make a pretty good prediction for more than a week out.

³In case you don’t believe me again, this time that I actually played on a softball team with someone that might be asked his opinion on something by a newspaper reporter from the Seattle Times, here is a picture of Dr. Nick “Blaster” Bond, my teammate. I took this picture him because I really liked him, and we both liked to play on teams with girls who could really play, too, then we would win co-rec titles because of how well THEY played. It was great! Nick always wore those ripped short-shorts no matter how cold it was, even if it was raining.

Famous scientist, quoted in newspapers, Blaster Bond, about 25 years ago. I took this picture because I liked him so much. — Famous scientist, quoted in newspapers, Blaster Bond, looking askance at some lollipop softball pitcher, about 25 years ago. Not the same Bond responsible for “Bond Cycles” in paleoclimate proxies, though I wish he was because then I would be more important as a person having more important friends I could mention.

Dusty parhelia

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.

SONY DSC — CIrrostratus fibratus with a faint 22 degree 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.

The End

Jeckyll-Hyde models have future AZ rain once more after Big Miss today

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. D etails…”

Weather 10 days from now remains uncertain

Hahahahah. That is the funniest thing I have thought of in a long time, and its not that funny. Take a look at this “spaghetti” plot for 10 days from now based on last night’s global data. The map is for 500 mb, about 15,000 to 20, ooo feet above sea level.

“High predictability”, even as far as 1o days out, is indicated by those areas where the bluegreen and red lines are all close together. For example, in the upper left hand corner, or in eastern Asia and the extreme western Pacific Ocean if you can make those areas out through all the lines. Also, both the red and bluegreen lines themselves are pretty close together there, and that says the jet stream is extremely strong there, normal for that region in wintertime. That jet stream is geographically anchored in that region and so not much changes there, even from winter to winter.

But then look what happens to that compact jet stream as it approaches the middle of the Pacific! It comes apart, line a twisted speaker wire that’s been untwisted. The bluegreen lines, representing a colder portion of the jet stream, mostly head off to the NE, while the red lines, indicating a warmer portion of the jet stream, split off and continue more or less toward the east across the Pacific and into the Southwest. However, the details of both flows, the northern one and the southern warmer one, are pretty unknown, as evidenced by all the “scatter” in the lines, the “bowl of rubber bands” you see in the east half of the Pacific and into North America (and elsewhere). Note that the lines are tending to group that bit more over the eastern US, suggesting higher predictability, and the presence of an upper level trough (and cold in the East).

For the sake of contrast, here is the same kind of plot for just 48 h from now, showing high predictability. Of course, things always go to HELL in the longer term, but today’s 10 day vagaries are more than usual.

So, what seems to be ahead for sure is a split in the jet stream in the eastern Pacific with one of the branches coming toward us. That is the good part since that branch can be pretty wet if it is strong. But, as you can see, exactly where it is, and that’s crucial, is really anyone’s guess at this point. That warmer jet has to be south of us to have any rain with the disturbances that are shuttling along in it. And if you look over AZ, the red lines of the warmer jet are all over the map, literally.

Hence, to use an old word there, particularly uncertain times ahead. In fact the only thing that is certain, is with the southern branch of the jet in this area, there will at least be passing regions of clouds as upper air troughs go by. Will they, like yesterday, only be Cirrus? Or rainy Nimbostratus?

The second shot shows a nice “parhelia” or “sun dog” at the far right, caused by plate-like ice crystals falling face down, the normal mode. The final shot has some the rarely seen Cirrus castellanus, Cirrus clouds with little turrets or humps at the top.

Complications in the sky

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…

Here is yesterday’s cloud movie presented by our own University of Arizona Wildcats. This will help.

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.

The End.