Category Archives: Cirrus clouds

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"Altocumulocirrus", Cirrus clouds, Cumulus clouds, Definitions

Behold! Cirrus!

We often have phony dramatizations suggested by titles with exclamation marks, and frankly, today is no exception.   I do like Cirrus, though.  Hope you do, too.

Why like Cirrus1?

They provide a lot of nice sunrises and sunsets.  EOM.

Example of a recent CIrrus sunset, FYI.
An example of a recent display of Cirrus at sunrise.

 

Yesterday’s displays of Cirrus, ending with a scruff of Cumulus toward Pusch Ridge:

7:29 AM. Cirrus castellanus, or what we sometimes call, “Altocumulocirrus” because it looks so much like just Altocu.

Rain’s on the doorstep!

The End

 

Cirrus clouds, Definitions, Kwajalein, Russian book on flying, Spaghetti plots, Sunsets, The weather WAY ahead (10 days or more)

“Delta model”? Will someone have cold spaghetti on their face?

Yesterday, after I finally saw the model run based on global data from 5 AM AST  for Feb 6th, CMP (the writer) was gloating that bit.  The troughy, cold spaghetti for AZ, that which had been excitedly written about yesterday,  was being confirmed; the interpretation right on, it seemed.  Why even look at more model outputs until later January, I thought.
Then,  just now in the pre-dawn darkness, I examined the computer outputs from last night’s 5 PM AST global data, also for Feb 6th, 5 PM AST.    That is, global data crunched just 12 h later than the first panel I was gloating over, feeling really great about.
But, a completely, ghastly different weather regime had popped out!
How could this be?  We don’t know.   Relatively small changes would be expected, but the model outputs should gravitate back to where spaghetti placed the high and lows aloft.  But this change was ridiculous, and must be rejected.
Some people, like neighbor and big professor “emeritius” of meteorology at Colo State U,  Bill Cotton, refer to such differences as “delta model”.    “Hence”, if that word is still used, today’s title.
(For snowbirds who have just moved to Arizona, the maps below have been annotated to show where you are relative to the rest of the US).
Yikes!
The first regime is cold, maybe some snow down in Catalina at some point about this time (early Feb),  whilst the 2nd regime for the same time is suggests warm conditions, and definitely dry;  no rain nowhere.
CMP (the writer) spoke of a high probability, based on ensemble spaghetti, of cold and lots of precip chances here in Catalinaland beginning at the end of January through the first week of February  So, what’s up with that, this dichotomy?
Moving on to a new topic, let us look at last evening’s sunset rather than ponder what happened to the weather computer model, that is, which panel  above is  likely correct1:

6:09 PM. Cirrus uncinus and other forms of Cirrus provided a beautiful sunset highlight.

 

The End.

—————————————

1The first regime above, the troughy, cold one, is strongly supported by ensemble outputs whose crazy-looking output plots are fondly referred to as “spaghetti”.  The second panel served up from just last night’s 5 PM AST global data is not.
Have not looked at last night’s ensembles, but will ignore the bottom run anyway;  will not panic as weaker elements might, that is, change my overall interpretation of troughy conditions in late Jan, early Feb., that is#2, reverse course now, predict drought and warmth  for early Feb. , that is#3, “yo-yo”, as forecasters describe reversing course, confuse the public, lose credibility, where are my pills?
……yet. :}.
Still, “egad re this delta model”,  as Bill likes to say.  Its astounding!  A total joke!  The later one to be totally and completely rejected!
In no way did I expect to see what’s in the bottom panel, which is now above here!  Trying to not panic real hard.  (more kidding)
Still, how can there be an outlier of that magnitude as we see from last night?  Must be a real bad error somewhere (maybe 2 kts of wind, 1.5 deg in temperature, wind direction, 5 decameters in geopotential height, etc), not an itty-bitty error as ensembles start with.  Maybe Russian2 hackers did something, the North Koreans, or the Chinese?  Just kidding
with weather noise and pseudo-paranoia, your Catalina cloud-maven of sorts.
Speaking of Russia,  my great-grandparents emigrated from the Ukraine, here’s the cover of my latest book, published a few years ago.  Well, its not my book per sé, but all the cloud photos in it are mine!  How great izzat?
A book about flying. I asked that my contributions be dedicated to A. M. Borovikov, the great Russian cloud physicist. Did a lot of airborne stuff in the 1950s and 60s.  The cover photo above I took while in KWAJEX in 1999, a tropical cloud study featuring several research aircraft centered at Kwajalein Atoll, Marshall Islands.  Of note, seeing a monument to the bravery of the Japanese soldiers (fair enough), and seeing a Japanese military plane land there during our six weeks.  Gorgeous clouds!  Kwajalein Atoll is the terminus of missle launches from Vandenberg. Alerts on TEEVEE tell you when they’re coming in.  Unlike in Hawaii where people panic when missles are coming in, folks on Kwajalein go out to “see the show.”
Altocumulus clouds, Cirrus clouds, Definitions, Lenticular clouds, Nimbostratus, Spaghetti plots, Stratocumulus clouds, Sunrise, Sunsets, The weather WAY ahead (10 days or more)

Sutherland Heights logs 0.22 inches yesterday; Jan now at 1.32 inches; average is 1.60 inches, water year at 1.71 inches

0.22 inches was, indeed. how much rain fell in the form of drops  from Nimbostratus clouds yesterday as a modest little rain band generated by a rapidly moving trough swept through during the afternoon.  Regional precip values can be found here.  Our local area got the most, up to about a quarter of an inch, as often happens in marginal storms.

Yesterday’s storm marked the beginning of the new, more normal weather regime for southern Arizona, as has been blabbed about here in recent weeks.  No more week after week of droughty weather with temperature far above normal, the kind of weather that has marked this whole fall and winter so far!  I. e., “Thank you very much, a snowbird might say,  but get the hell out!”,  the rest of us might conjure up, thinking about the needs of our  desert’s wildlife and vegetation.

Indications are now that below normal temperatures and above normal precip are ahead for us and all of Arizona in late Jan and early February.

The evidence for these claims?

Below, the stunning, jaw-dropping evidence for this seemingly outlandish assertion in the form of an ensemble (spaghetti) plot generated by NOAA last night.  I have followed these charts for almost ten years now, and I cannot remember when such a strong signal (clustering of flow lines) 15 days out has occurred before in our region.

So, excessively excited this morning when I saw it!  Its been annotated with excitement text.

This troughy pattern begins to take place on January 30th.  Until then, a strong but dry cold front with a lot of wind comes by in a few days, on the 25-26th.

Valid at 5 PM AST, February 4th. You can pretty much count on a trough hereabouts in two weeks. Since the blue lines, the colder portion of the jet stream,  do not dip down this way so much, our troughiness likely would be in the form of something we call a “cutoff low.”   A full latitude trough extending from the “blue jet” up there in Canada, instead of a “cut off”, would be excessively cold.  We probably don’t want that anyway.

 Yesterday’s clouds

The whole interesting, if excessively gray story is shown below:

7:24 AM. It was breezy already, and with Cirrus underlain by Altocumulus lenticularis clouds in the lee of the Catalina Mountains, you knew that a storm day was ahead without turning on your favorite TEEVEE weatherman.
8:53 AM. With Cirrus and Altocumulus spreading rapidly from the SSW, lenticulars downstream from the mountains, the wind gusting to 25-35 mph, you knew a great gray cloud day was in store!
11:32 AM. Before long, an entire sheet of Stratocumulus spread over the sky, making you sure that rain would fall.
12:50 PM. First drops begin to fall on Sutherland Heights. That layer of Stratocumulus appeared to be deepening as it approached from the SSW to where the tops were getting just cold enough upwind of us to produce ice and snow that melted into those sparse drops.  Not enough ice /snow formed to hide the bases, though, in virga.
1:26 PM. Snow begins to fall on the Lemmon.
2:04 PM. Lower Stratocumulus clouds begin to show up below the original deck that overran us.

 

3:16 PM. Pretty and dramatic.  Stratocumulus piling up over and upwind of our Catalina Mountains/Pusch Ridge.
3:19 PM. Oh, so pretty.
3:27 PM. Crazy, I know, but I thought these scenes were so pretty!
3:28 PM. As that rain band approached there were some nice lighting highlights.
3:40 PM. Here comes that rain band  across Oro Valley/Marana.
4:19 PM. A truly great scene for a desert; mountains partially obscured in precipitation.
4:19 PM. Nimbostratus. Its hard to get a better photo of rainy Nimbostratus than this. Drops coming off the roof, NOT raindrops, can also be seen.  This was at the peak of the rain, too!  Very exciting.
5:54 PM. Sunset Stratocumulus, hold the ice. Yet, that Stratocumulus was cold, way below freezing.

 

The weather way ahead

The title sums up where we are now.  Will we go have more rain? Oh, yeah.  But not right away, as you already know.

 

 

Cirrus clouds, Definitions, Lenticular clouds, Stratocumulus clouds, Sunsets, Thunderstorm day

Sutherland Heights rain: 0.97 inches and counting (as of 9:54 AM)! Thunder, too!

What an amazing and “productive”  little rainband that was just after midnight!  And more rain is likely with weaker bands just upwind here at 4 AM.  Could we really approach an inch?  Amazing.  Didn’t seem possible in this small mind that we could amass that much.  For a full regional rain table, go here to the ALERT gauge records.

An even more dense collection of rain totals can be found on the Weather Underground map for the Catalina/Tucson area *click on the precip button when you get there, radar, too).  We seem to have done better than just about anywhere else in the state, with 2.94 inches at Biosphere 2 leading the way (thanks to those “TSTMS” and the rain gushes with them, I am sure.)

Now, after this ends, a long dry spell has to be endured, at least until around the 20th of Jan, at which time we hope the troughs and rain threats at least,  will begin to barge in every few days, namely, and pattern more typical of winter sets in.

Yesterday’s clouds

8:31 AM. Typically lenticular clouds form in the lee of the Catalinas as storms approach. Lenticular clouds are good signs of deteriorating weather ahead since they are usually accompanied by strong, moistening winds aloft.
8:31 AM. Zoomed view of one lurking just beyond the crest of Ms. Mt. Sara Lemmon. The higher clouds were Cirrus (which can have grayness when the sun is low).
10:24 AM. Wasn’t long before this deck of Stratocumulus raced over the sky, adding that feeling that rain is a comin’.
11:32 AM. Some tendency to form the new supplementary cloud feature, termed, “asperatus undulatus” is shown here at the base of the Stratocumulus deck.
1:13 PM. Got excited when ice began to show up, with virga and light rain showers here and there.  Can you see that icy top receding from the Catalinas?  It wasn’t that high and cold, either.
1:14 PM. Nice highlighted view of Biosphere 2, with light rain showers in the background. Whodda guessed Bio2 would get 1.93 inches overnight? Not me!
1:59 PM. Light rain showers began to fall from that Stratocumulus layer, now pocked with buildups (Stratocu castellanus?) as temperatures aloft above cloud top cooled.  The haze is due to rain falling from overhead.  It did not measure.
1:59 PM. Looking upstream and the Stratocumulus deck whose tops were just ascending to the ice-producing level as they approached Catalina from the SSW. That clearing on the horizon maintained throughout this cloud and shower period suggesting it was caused soley by the lifting of the air as it approached the higher terrain of Catalina and the mountains. It was soon to disappear.
3:02 PM. Falling apart.
3:49 PM. Gone.  Yes, once again, the clearing before the storm.  A storm is approaching, 100% chance of rain within 10 h, and yet, the clouds are disappearing!  This is a common here; a dry slot in the moisture field OFTEN precedes storms here.  To some folks it may mislead them into thinking the storm’s a bust.  But not to us CMP’s, who seen this happen over and over again.
5:09 PM. Temperature’s in the low 70s; its getting to be a nicer day by the minute. Where’s that storm?
5:43 PM. Our storm and cold front marches toward us from somewhere over the horizon, though visually you’d never know it.  Wonder if the native Americans knew this odd sequence–probably.

The weather ahead

After the last drops fall today, we’ll suffer through another dry spell and warm up though about the 20th when a major trough passes by.

The End

Oops….  Have cameras ready for a great day of cloud shots once the sun breaks through.

Aircraft Produced Ice Particles, Altocumulus clouds, Cirrus clouds, Contrails

Cirrus uncinus scenes for a lifetime, well, mine, anyway

5 Comments

I hope you had a chance to venture out late yesterday morning and see some of the most spectacular Cirrus (uncinus) displays with HUGE streamers that you will ever see.

The early Cirrus cloud were nothing very special, not showing clues about what was to happen a few hours later:

7:46 AM. A complex sky with Altocumulus on the right and various species of Cirrus such as Cirrus spissatus, center.

But by mid-morning, racing in from the west, these:

10:58 AM. From the Rillito Bridge at Swan, this amazing scene with Cirrus uncinus and those gigantically long tails of ice!
11:08 AM
11:08 AM. Mimics trees in a way, both reaching upward.
11:14 AM.
11:12 AM. From the Rillito Bridge at Swan again.  Kind of running around like a chicken with its hat off!  The heads of the Ci unc are overhead.
11:11 AM.
11:14 AM. One final shot.

—————

There was an interesting  contrail distraction later that day.  Are these “castellanus” crenelations, or is it perspective?  Those knobs are usually pointed downward due to the action of the wingtip vortices that take them downward behind the plane.  Maybe they’re just sloped down at us, not puffed up.

1:10 PM.

—————-

Late in the day some Altocumulus advanced from the west, providing a nice sunset, but a layer once again impacted by aircraft holes.   Can you find them (with their trails of ice slanting downward?)

5:38 PM.

The End

Well, there is still a chance of some rain late in the month, late or after the TG holiday weekend…..  FIngers crossed.   Poor wildflower seeds.

Altocumulus clouds, Altostratus clouds, Cirrocumulus clouds, Cirrus clouds, Definitions, Stratocumulus clouds, Sunsets

Some recent pretty clods

2 Comments

Been busy as a briefly unretired science worker (gave a stressful talk at a university last week) and thought maybe a lot of usual drop ins to this site might not anymore.   So, in the title for today,  am reaching out to a new demographic: persons interested in congealed soil matter.  They might later, after stopping by, discover a new interest; that in clouds, pretty ones.  Most of the cheap tricks I try like this don’t have any effect, though.  Oh, well.

Let us go forward after backing up:

November 3rd

8:01 November 3rd. OK, I’m way behind! Flock of Cirrus uncinus overruns Catalina and environs.
8:02 AM. Looking SW from Catalina. So pretty with the deep blue skies we have at this time of year due to sun’s lower angle in the sky.
9:16 AM. Look how different, even unreal, that flock of Cirrus looked when leaving us. Looking NE toward the Charouleau Gap.

But the Cirrus kept coming and more odd sights were seen:

10:06 AM. Two levels of Cirrus can be seen. This vertical white patch is likely a few thousand feet lower than the crossing faint strands center and right side,  which are likely above 30,000 feet above the ground.  The heavier Cirrus (spissatus) in the distance is also lower than the strands.

Heavier Cirrus, increasing and lowering to Altostratus finished off the day as a heavy shield of middle and upper clouds raced toward southern Arizona from the Pacific:

3:08 PM. Cirrus spissatus here, too splotchy in coverage to be Altostratus. Nice subtle lighting effect on the Catalinas…

 

“Due to time constraints, we move ahead in the action…”

November 4th

7:27 AM. Classic A row of Altocumulus floccus and castellanus underlie an Altostratus layer.  Where the bases have disappeared, at right, are termed “floccus”, if you care.
8:00 AM. Altostratus, some lower Altocumulus  castellanus with graniteen boulders and a coupla saguaros.
8:59 AM. Bird collective watches in hopes that the darkening, lowering Altostratus layer  (with some Altocumulus) will bring rain. It didn’t. “Dang”, we say here.
4:51 PM. All of the higher layers were gone, leaving only a lowest, but thin scattered to broken Stratocumulus clouds. 🙁  All in all, it was a good day for hiking and other outdoor activities.

Sunday, November 5th:

6:01 AM. Flock of CIrrus uncinus and spissatus again advances on Catalina.
6:21 AM. a closer view. Here they seem to be uncinus with fibratus. Stratocumulus clouds were topping the Catalinas, too, indicating more humidity than we have been seeing most of the past few weeks.
8:38 AM. I thought this was an especially spectacular scene, this lattice of Cirrus racing toward us.  Hope you did, too.

4:26 PM. Perhaps the brightest example of iridescence I have ever seen! Just spectacular for a few seconds in this patch of Cirrocumulus. Iridescence is caused by diffraction around the tiny of droplets, less than 10 microns in diameter, as are present when a cloud just forms.

5:09 PM. Seeing this scene of Altocumulus, you KNEW you were in for a superb sunset.  It didn’t disappoint.
5:39 PM.
5:40 PM. There is no virga here.
5:44 PM. Super!

The weather just ahead

The Wildcat Weather Department model is foretelling perhaps a measurable rain event between this afternoon and tomorrow morning at 7 AM!  Heavier rain is foretold to be south of us, but just a slight error would mean something more substantial.  Hoping for error!  A sky covering Altostratus layer is just about assured with a lowering tendency as the day goes on.  Should see some Altocu , too, a day a lot like last Saturday.

The End

"Altocumulocirrus", Altocumulus clouds, Cirrus clouds, Definitions

A study in cold Altocumulus and about a balloon mistaken for a space object

Balloon sounding released from the U of AZ about 3:30 PM AST. Altocumulus clouds were no less than 21,000 feet above Catalina at -20°C (4°F).  Sounding courtesy of IPS Meteostar.  BTW, it wasn’t this balloon–see below.
11:15 AM. A stationary balloon that hovers SE of Tucson.  Can you find it?  I had never noticed it before and at first thought it was in space, above the Cirrus!  How crazy was that?  Likely to be a device up there  to monitor the US Border.
2:55 PM. Cirrocumulus with an aircraft produced ice canal in it , tight half of photo (that ice cloud now termed, “Cirrus anthropogenitus”).
4:02 PM. A complex sky for sure. Little tufts of Altocumulus way up at 21,000 feet above ground level, with Ac castellanus turrets (e.g., left above horizon).  SInce those turrets are reaching up to temperatures well below -30°C (-22°F)  they’re converting to all ice (such as center right).   Those icy ones would be called, “Cirrus spissatus.”  It would also not be untoward, and I know you don’t want that, to just call those deeper clouds with turrets on the left, “Cirrus castellanus.”

5:56 PM. Lines of Altocumulus make for an OK sunset.

Another pretty cloud day ahead.  Though most of the Altocumulus clouds are flat, there are some whoppers off to the north now, Ac cas so large they might have to be called Cumulonimbus, certainly large enough to produce radar echoes, maybe a sprinkle at the ground.

Lots of wind tomorrow, as you likely know,  but no rain in sight still.  So, October almost surely will end as a rainless month.  Our average for October is just over an inch of rain!

The End

"Altocumulocirrus", Altocumulus clouds, Cirrus clouds, Definitions, Virga

Some recent clouds

4 Comments

May 24th:

DSC_3906 DSC_3912 DSC_3907 DSC_3900

May 25th, yesterday, starting with sunrise color

DSC_3921 DSC_3917DSC_3922

Later yesterday morning, some interesting “Altocumulocirrus”, a rare breed indeed, mocking/mimicking Altocumulus.

Maybe Cirrus floccus would come closest to the true name, but to every eye but that of a genuine cloud maven person, it would be deemed just “Altocumulus”.  Check these out to see how good you were–and NO correcting your cloud diaries!!!!

DSC_3926
5:47 AM. Two layers are visible, a distant Altocumulus castellanus one, and the higher, much higher, cirriform clouds resembling Altocumulus. If you don’t believe me, the sounding from the U of AZ is below.
The TUS balloon sounding for 5 AM AST yesterday. The Altocumulus patches were up around 16,000 feet, and the cirriform clouds around 33,000 feet and at about -50°C
The TUS balloon sounding for 5 AM AST yesterday. The Altocumulus patches were up around 16,000 feet, and the cirriform clouds around 33,000 feet and at about -50°C (-58°F).  Had to cuss that bit because I sensed some doubt out there.
6:38 AM. Same cloud layer. Seriously, how can you not call this "Altocumulus", it mimicks it so well. But these globules are all ice, no liquid water of course anywhere near -50°C unless we believe the reports of Simpson (1963) who purported liquid at -62°C. Nobody believed him though; me ,neither.
6:38 AM. Same cloud layer. Seriously, how can you not call this “Altocumulus”, it mimicks it so well. But these globules are all ice, no liquid water of course anywhere near -50°C unless we believe the reports of Simpson (1963) who purported liquid at -62°C. Nobody believed him though; me ,neither.
7:37 AM. Another view of this cirriform layer making a mockery out of Altocumlus. Note that there is that tiny bit of shading, too, in these cloudlets.
7:37 AM. Another view of this cirriform layer making a mockery out of Altocumlus. Note that there is that tiny bit of shading, too, in these cloudlets.
5:24 PM. The convection leading to cellular structure was still evident pretty much the whole day. Again, we have a problem. Shading like this is not officially permitted with in cirriform clouds except in the "spissatus" species. One would be thinking "Altostratus" here since that cloud is widespread and can have gray shading. When you look at the TUS sounding nearest this time, you find that the moisture is still contained in the upper reaches of the troposphere, where it was in the morning, and that would be in the "etage" for high clouds, 33,000 feet or so above sea level.
5:24 PM. The convection leading to cellular structure was still evident pretty much the whole day. Again, we have a problem. Shading like this is not officially permitted with in cirriform clouds except in the “spissatus” species. One would be thinking “Altostratus” here since that cloud is widespread and can have gray shading. When you look at the TUS sounding nearest this time, you find that the moisture is still contained in the upper reaches of the troposphere, where it was in the morning, and that would be in the “etage” for high clouds, 30,000 feet or so above sea level.
The TUS balloon sounding for 5 PM AST, May 25th. The temperature of that icy layer ranged from about -35°C on the bottom to -60° C at top.
The TUS balloon sounding for 5 PM AST, May 25th. The temperature of that icy layer ranged from about -35°C on the bottom to -60° C at top, so there would not be any liquid water in it even though is might appear in some places.  Where’s my Lear jet?  Need to check these things out and in a hurry!

Now for some prettiness from yesterday evening:

DSC_3949 DSC_3945DSC_3959 DSC_3956

The End

Altocumulus clouds, Altostratus clouds, Cirrus clouds, Sunrise, Sunsets, The weather ahead

Sunset was pretty good; raindrops tomorrow morning? In nine days as well?

2 Comments

Haven’t had much to say, brain pretty empty again after the big review of the NAS 2003 review which really needed reviewing and commenting on real bad….

(More “late homework” in the offing.)

———————-

Nice sunset last night; we have had a series of pretty nice ones over the past few days.

April 26th. Sunset over the Charoulou Gap.
April 26th. Sunrise over the Charouleau Gap.
DSC_3471
Orangy mountains highlighted by a gap in the Altostratus layer that allowed the setting sun to shine through.
DSC_3474
7:04 PM. There was some turreting in this line of Altostratus that passed over, and because of those deeper tops, indicating stronger, if still slight updrafts, larger snow particles developed and produced this line of heavier virga underneath it.
DSC_3479
7:10 PM.
DSC_3462
A contrail that’s more than about ten minutes old, now, after the new Int. Cloud Atlas has been released, termed, Cirrus anthrogenitus, maybe castellanus in this case, too.

From IPS MeteoStar, this interesting map for tomorrow morning.

The orangy colors denote the strongest winds in “Jetty Jetstream”, and as you know, the colder, low clouds, ones capable of reaching the temperatures where ice forms, are contained within that ring of strongest winds at this level (500 mb).  So, while the models I have looked at so far have no rain here, I think there’s a pretty good chance of a rogue shower tomorrow morning anyway.  At least there should be some nice Stratocumulus/Cumulus tomorrow and some will have ice in them.   As you know, it’ll be awful windy today, too, maybe 40 mph or so in brief gusts here in The Heights of Sutherland.

Also will be looking for some nice lenticulars since “Jetty” will be right over us, but a little toward the warm side where lenticulars mostly occur.

Map valid for tomorrow morning at 5 AM AST.
Map valid for tomorrow morning at 5 AM AST.

In the meantime, spaghetti suggests a big trough in our area again about nine days from now.  The later ACTUAL model outputs don’t show much of anything.  What’s up with that?  I’m hanging with spaghetti that later model runs will indicate a strong trough, and at LEAST another pulse of cooler air, and another minor chance of rain as we are going to see today and especially tomorrow as when become within the “ring of winds” aloft.  Didn’t Johnny Cash sing something about that? Maybe it was Wall of Voodoo…

Below, some spaghetti for you showing a big trough over Arizona and the Great Basin which is not much reflected in the actual models, as noted.  But, just watch my friend, how those model outputs will change to reflect a bigger trough about this time!

Valid at 5 PM May 7th.
Valid at 5 PM May 7th.

 

The End

 

Aircraft Produced Ice Particles, Altocumulus clouds, Cirrus clouds, Definitions, New International Cloud Atlas

Looking ahead to May, and something about the new Int. Cloud Atlas

April’s been kind of a weather dud here in Catalina so far (no rain so far, and the chance on the 20th, mentioned here some weeks ago, has receded to Utah and points north), so lets take a look at how May is shaping up, only two weeks ahead:

Valid at 5 PM, May 2nd. Nice!
Valid at 5 PM, May 2nd. Nice!

I thought you’d be pretty happy when you saw this, as I was.

 

BTW, there is a new International Cloud Atlas out there.

Its possible there is a photo from Catalina, Arizona!  I have not checked yet.  Its just been published by the World Meteorological Organization of the United Nations.  Still needs a little work, but overall is VERY, very nice.  Came out out on March 23rd, so we’re a little behind here as usual.  The thing that makes it different from prior and sometimes flawed atlases is that each photo is accompanied by some weather data and in many cases maps, radar or satellite imagery at the time of the photo.

Some new expressions to toss around to your fellow cloud-centric folk are things like “Cirrus anthrogenitus”–Cirrus evolved from contrails and “Cumulus flammogenitus”, a Cumulus formed at the top of a fire, something we used to call, “pyrocumulus”, an unofficial term that somehow seems preferable to “flammo”.

However, something that has drawn great attention over the past 20 years or so was not given a name, aircraft-produced ice in Altocumulus and Cirrocumulus clouds, which have been referred to by Heymsfield and colleagues as “hole punch clouds.”1

Hole punch clouds pdf

Ice canals amid Altocumulus are also fairly common.  Ironically, a hole punch cloud with ice in the center, and an ice canal in an Altocumulus cloud layer can be readily seen on the new International Cloud Atlas submission site, now closed.  They’ve mistakenly, IMO, referred to “ice canal” photos as “distrails” without mentioning the ice canal “cirrus” down the middle.  Formerly, distrails were clearings produced by aircraft in thin clouds without any change of phase in the cloud induced by the aircraft, unlike those holes and clearings produced when the ice-phase is triggered by an aircraft passage.

Certainly a “hole punch” cloud is not a distrail, a linear feature, and should have a separate nomenclature.

In keeping with the new terminology regarding “anthro” effects, maybe it should be, since we’re talking about the Cirrus induced by an aircraft, albeit at much lower levels than true Cirrus clouds:

“CIrrus Altocumuloanthroglaciogenitus.”  (??)

Here’s a classic one of those that erupted over Catalina, posted here last January:

11:27 AM, January 2nd. The ice canal in the middle of an Altocumulus layer that might in the future be termed a Cirrus altocumuloanthroglaciogenitus.
11:27 AM, January 2nd. The ice canal in the middle of an Altocumulus layer that might in the future be termed a Cirrus altocumuloanthroglaciogenitus.

 

DSC_3336
5:53 PM. An example of the various cirriform clouds we’ve been treated to the past week or two, ones that have been giving us those nice sunrises and sunsets. Doesn’t seem like there’s been a cloud below 50,000 feet for about that long, too. (I’m exaggerating just a little.)
7:04 PM. Seems like sunsets are occurring later and later.
7:04 PM. Seems like sunsets are occurring later and later.  Here the setting sun allows some of the “topography” of Cirrus clouds to be accentuated.

 

The End

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1It should be pointed out immediately if not sooner  that Catalina’s Cloud Maven Person had plenty of time to rectify, or suggest changes to the Atlas as he could have been part of this process, but didn’t really do anything except submit some images for consideration.