Category Archives: Altocumulus clouds

Raindrops fall on Catalina ending rainless October

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A trace of rain was officially recorded in Catalina at this site ending prospects of a rainless October.  It fell from high-based Cumulonimbus clouds in a band, partially lining the NW horizon that could be seen as the sun rose yesterday.  Some ants were injured by the falling drops, ones that reached millimeter sizes and fell at 5-8 mph, though in some areas, winds of 10-15 mph added to drop impacts.  Flying insects, while  obliged to avoid the watery missiles, were able to do so with ease due to the appreciable spacing between the drops of several feet.

Due to the short-lived hydrometeor events, many humans were unaware that rain had fallen in Catalina on more than one occasion yesterday.  That’s why we blog here.  Weather and cloud news you can rely on.

How high were the bases of those precipitating clouds spewing snow virga that melted to rain?  Higher than the freezing level! Haha..  The balloon sounding profile started with the Altocumulus perlucidus layer at 18,000 feet above sea level, 15,000 feet above Catalina, bases at -11°C.  By evening the lowest moist level had lowered to 14,000 feet ASL (11,000 feet AGL) and -3°C.  However, that last moist level had to be a bit lower than those snowy cloud bases IMO–we know that the moist level almost always lowers.

So cloud maven person will make the definitive call that the rainy (well, sprinkly) cloud bases were at 16,000 ASL (13,000 feet AGL) when they passed over, if that makes any sense or is anything you really care about.

Yesterday’s clouds

6:42 AM. Altocumulus perlucidus at -11°C (12°F). No ice evident.
6:43 AM. High-based Cumulonimbus erupts to the distant NW. Altocumulus castellanus layer from which it erupted can also be seen. The snow falling from cloud base is also evident, melting to rain just above the horizon.
6:54 AM. By this time the full band to the NW whose tail was to pass over us about mid-day is evident. Plenty of snow can be seen falling from these modest, high-based Cumulonimbus clouds.

 

As rain fell……this sky, 12:30 to 1 PM:

Kind of pathetic really; no shafting whatsoever, much less virga than on the horizon yesterday morning.  So our end of that band was so weak it was just barely able to get some drops to the ground.

Looks like this is it for rain in October 2017.  However, November 2017 appears to look much brighter for substantial, dust-removing rains in Catalina beginning in the first 10 days!

The End (I missed the sunset due to a social engagement–hope you saw it wherever you were).  Probably was pretty nice.

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

Post includes rainbow photos for popularity’s sake; 0.14 inches of rain (what other “inches” of something would it be?) dampens Sutherland Heights

Nothing much else here of too much interest except the usual cloud blabber… haha

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7:00 PM.
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7:04 PM. Hope you saw these!
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5:50 AM. Moon dodging clouds, Altocumulus ones.  Moon dodgers?  Did you know that the University of Washington sport’s teams were once known as the “Sun Dodgers”?  How funny izzat?  It’s truly amazing to me what you learn here.
2:47 PM. Icy tops move toward the Catalina Mountains.
2:47 PM. Icy tops move toward the Catalina Mountains.
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3:54 PM. Not much going on over the Catalinas. But, can you spot the first ice from these clouds? You’d have to be pretty darn good to do that.
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3:54 PM. Zooming…. There it is! Have to look hard for the arrow and the bit of ice haze below that flat section. This would be a great ob day for an aircraft, since it would mark the threshold of temperature where ice is  starting to form. Deeper, colder clouds from this threshold level would have more ice, a lot more.  This level can vary from day to day, depending mostly on the sizes of droplets in clouds.  With bases near freezing yesterday, this level would likely have been at the -12° to -15°C level, up around 20,000 feet above sea level.  Bases were around 14,500 feet above sea level.
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5:23 PM. Nice lighting. I like lighting and lightning, no so much lightening, since a storm could be ending then, or if its around dawn, its OK.  You can see two eyes, squinting….
5:43 PM. Nice base streaming from Pusch Ridge enlarges as it came almost overhead! Looks promising for a SPKL. Moving car out from carport so's I don't miss a few drops.
5:43 PM. Nice base streaming from Pusch Ridge enlarges as it came almost overhead! Looks promising for a SPKL. Moving car out from carport so’s I don’t miss a few drops.
5:54 PM. Fine strands of rain now becoming visible!
5:54 PM. Fine strands of rain now becoming visible!
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6:19 PM. Strands of rain in full display in RW-. Its measuring, not just a few drops! Need to roll up windows in car!
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7:13 PM. Not much happened just a little west of Catalina. Nice sunset, too.

Looks like another day for a chance of rain late….

The End

Powering up

Not much going on lately, so will dip into the archives from two days ago.  One cloud in particular was so spectacular in its defiance of gravity, rocketing upward the morning of the 4th.  So here are shots from that day…

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6:46 AM, Aug. 4: The day began with a pretty normal looking patch of Altocumulus perlucidus (honey-comb pattern). No virga, so its likely not too cold. The sounding suggests it was up at 16,000 feet ASL, or 13 kft above Catalina at about 0°C (32 F).

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10:05 AM. Thar she blows! Just a spectacular jut from over the Mogollon Rim area, and a telling sign of what was immediately ahead for us.
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10:53 AM. Was doing yard work, under some trees, and then came out to see this amazing sight (Cumulus congestus erectus). Ran for camera, you have just seconds to a minute or two before it begins to fall apart due to entrainment of dry air that makes a cloud look ragged and frayed. Will it form ice? Is it cold enough up top?  Should show up in a couple of minutes if it is going to.
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11:00 AM. Ice formation well underway as you can see by the frizzy, fibrous texture above the halfway mark up this cloud. At the time it seemed like it might be a big day for TSTMs with this kind of vertical rocket cloud shot so early. But, no.  I would term this cloud, a Cumulonimbus calvus or capillatus, even though there is no visible rainshaft yet.
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11:00 AM. Going zooming…you can see that virtually this whole top is glaciated, and that fingerling, top left, shows some fallout of ice, likely aggregates of ice crystals. When concentrations are high, as would be the case in this glaciated turret, the crystals often lock together to form snowflakes. In cloud microstructure and modeling terminology, the stuff falling out would be termed , “precipitation ice”,  and most of that in the  fingerling, “cloud ice.”  I hope you’re happy now.
11:05 AM. An icy being seems to be leaping out of the new Cumulus congestus clouds that sprang forth so rapidly. That icy "being" is all that's left of the original turret.
11:05 AM. An icy being seems to be leaping out of the new Cumulus congestus clouds that sprang forth so rapidly. That icy “being” is all that’s left of the original turret.
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11:09 AM. Kind of in the area of “beings” now. Those new Cumulus cloud sprouted up rapidly to fill the void left by our first cloud. But here it appear to take on the shape of a being waving, “Hey, look at my icy left hand!”
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11:52 AM. Thought this frizziness, texture of the ice made me think they might be “warm crystals”, that is ones that form at temperatures higher than -10°C, which would be needles and sheaths…. I sure wish I had a Learjet, get up there in a hurry, find out for sure…. The afternoon sounding supports that speculation with tops likely limited to those higher temperatures, but not the morning one
12:49 PM. One Cumulonimbus calvus stage here, was potent enough to produce a bit of thunder, maybe the last we'll hear for many days.
12:49 PM. One Cumulonimbus calvus stage here, was potent enough to produce a bit of thunder, maybe the last we’ll hear for many days.
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1:00 PM. Looking to the west, you could see the drier air moving in as evidenced by the lack of any buildups for as far as you could see, and also in the pitiful clouds over the Tortolita Mountains. It was a hard time, knowing the end was at hand.  And there it is, below:

The End

‘Nuf said

Now, that’s pretty funny.  We specialize here in too much said! Its a niche thing.  Of course, not enough can be said about our past July. Take a look:

2016-17 WY progress repor thru July

This, of course, was a new July rainfall record for Catalina/Sutherland Heights going back to 1977, anyway.  Had to adjust vertical axis of this chart, too.  Formerly, it stopped at only FOUR inches!  The moon lore was right!  It’s interesting how the ancient lore of early peoples that I made up a month ago was more accurate than the Climate Prediction Center’s prediction of an equal chance of above or below normal rain in southern Arizona while something incredible was on the doorstep!  Kind of like last winter in the whole West where record amounts of snow and rain piled up over a huge region, and that, too, was also unforeseen “going in.” Think how horrible it would be if those predictions were always right.  Sure, billions could be saved by such accurate outlooks, but then the element of surprise would be gone.  How bad would that be?

After the paucity of rain in the preceding five months, and with June carrying into around July 10th this year with its blazing heat and no clouds, all that rain that followed with thunderations day after day,  the attendant rain-cooled  “breezes” to 50 mph on occasions, blowing stuff all around everywhere, were sure welcomed (?).  (Another case of innovative punctuation to emphasize a point, whatever it is.)

Let us begin today by examining the greenth of the 2017 summer on our Catalina Mountains so far, thanks to July’s copious rains.  Hah! The climate really has changed.  Looking into growing bananas now…DSC_6621 DSC_6542 DSC_6534 DSC_6510Now for some cloud photos from yesterday:

9:40 AM. Like most of our summer days, it begins with mid-level layers of Altocumulus, in this case shown here, "translucidus" variety (rather thin, it is.) It was up around 13,000 feet above the ground, if you care.
9:40 AM. Like most of our summer days, it begins with mid-level layers of Altocumulus, in this case shown here, “translucidus” variety (rather thin, it is.)  It was up around 13,000 feet above the ground, if you care.
11:07 AM. As the Altocumulus clouds thinned, burned off, the rise of the Cumulus begins, here a gigantic one spurts upward telling you that there are going to be some blasters yesterday. Very exciting to see this. I can feel your heartbeat as you, too saw it.
11:07 AM. As the Altocumulus clouds thinned, burned off, the rise of the Cumulus begins, here a gigantic one spurts upward telling you that there are going to be some blasters yesterday. Very exciting to see this. I can feel your heartbeat as you, too saw it.
11:51 AM. Wasn't long before giant Cumulonimbus clouds were dumping over there on the town of Oracle. Nice town it is, btw. However, these clouds weren't much electrified, telling you that the updrafts weren't particularly strong yet, even though tops here were probably pushing around 30 kft.
11:51 AM. Wasn’t long before giant Cumulonimbus clouds were dumping over there on the town of Oracle. Nice town it is, btw. However, these clouds weren’t much electrified, telling you that the updrafts weren’t particularly strong yet, even though tops here were probably pushing around 30 kft.
11:52 AM. Cumulus congestus, and Cumulonimbus calvus start unloading over there toward I don't know where exactly.
11:52 AM. Cumulus congestus, and Cumulonimbus calvus start unloading over there toward I don’t know where exactly, but its just on the other side of the Tortolita Mountains.  You’ve probably noticed how clear the sky has been, completely free of haze.  That’s good for rain production, since the cleaner conditions are the larger the drops can be in the clouds because there are fewer of them compared to clouds forming on hazy days. Nat King Cole sang about summer haze as early as 1963, so we know that haze is not a new thing, like CO2 is.  You won’t find people singing about CO2 in ’63!
11:58 AM. The three amigos.... A slight rainshower can be seen in the slight haze in front of the mountains below the center Cumulus. Tops leaned way out again due to weak updrafts, and since rain forms in the upper portions, it fell away from the mountains in these weaker Cumulus.
11:58 AM. The three amigos…. A slight rain shower can be seen in the slight haze in front of the mountains below the center Cumulus. Tops of these spindily Cu  leaned way out again due to weak updrafts and and stronger winds aloft from the S.  Since rain forms in the upper portions, it fell a little away from the mountains in these weaker Cumulus.
12:02 PM. Dump truck, fully unloading! Not messing around anymore here.
12:02 PM. Dump truck, fully unloading! Not messing around anymore here.  With cloud bases running around 15°C (59°F) there was a ton of water up there.  Well, thousands of tons.
12:06 PM. I know what you're thinking: "Oh, look, a baby dump. Isn't it cute!"
12:06 PM. I know what you’re thinking: “Oh, look, a baby dump. Isn’t it cute!”  Suggests an abnormally narrow turret poked to far higher altitudes that those around it.
12:24 PM. More Cumulus congestus clouds joined the fray and this became a major 2 inches or more producing system over on the Tortolita Mountains.
12:24 PM. More Cumulus congestus clouds joined the fray and this became a major 2 inches or more producing system over on the Tortolita Mountains.
1:01 PM. Now the outflow surge can be seen on the left, pushing new Cumulus turrets above it.
1:01 PM. Now the outflow surge can be seen on the left, pushing new Cumulus turrets above it.  This was about the peak of it, as it gradually wound down.  Its  certain that flash flooding occurred with at least 2 inches  having fallen in the core.

Well, the day closed on a disappointing note as Cumulonimbus debris clouds overspread the sky, killing new convection.

5:45 PM. Altostratus "cumulonimbogenitus." The day went quietly into the night.
5:45 PM. Altostratus “cumulonimbogenitus.” The day went quietly into the night.

The weather way ahead

Looks like below average rain for August.  :(, as we say.  Hoping for error here.  Average August rainfall here in Catalina/Sutherland Heights is 3.16 inches.

 

The End

Some recent clouds

May 24th:

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May 25th, yesterday, starting with sunrise color

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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!!!!

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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:

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The End

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

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.)

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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.
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Orangy mountains highlighted by a gap in the Altostratus layer that allowed the setting sun to shine through.
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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.
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7:10 PM.
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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

 

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.

 

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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.

High cold ones, and lots of patterns in a complex sky

In particular, those Altocumulus clouds, “cold” Cirrocumulus (ones that transform to ice immediately),  and those “Altocumulocirrus” clouds combining  with  scenes of “regular” cirriform clouds.  Lots of interesting sights to have seen yesterday.  All these the result of marginal moisture aloft and strong winds, up around 100 mph at the highest Cirrus levels.

Let us begin as cloud maven folk by examining the late afternoon sounding launched from our Wildcat balloon launching machine at the University of Arizona, courtesy of IPS Meteostar:

The temperature and humidity profile obtained from a weather balloon launched at about 3:30 PM yesterday afternoon from the U of AZCats.
The temperature and humidity profile obtained from a weather balloon launched at about 3:30 PM yesterday afternoon from the U of AZCats with some suggested cloud levels.  The Altcoumulus level is in doubt. the others are pretty straight forward.  Notice how high those little Cu were yesterday afternoon, about 16,000 feet above sea level, or about  13,000 feet above Catalina, with bases at a cold -13°C or so.  No ice came out of those, though.  Likely droplets too small, or short-lived.
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6:45 PM. A very narrow line of Altocumulus castellanus and floccus virgae approaches Catalina.
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6:46 PM. Let us exercise our curiosity and examine this element in more detail below.
6:47 PM. Altocumulus floccus virgae. Another example of how the top of a storm, as here, can be composed of droplet cloud while the ice that forms in it falls out below. Here, the extreme dryness underneath the Altocu prevents long trails. The ice crystals wither so that they have almost no fallspeed soon after they have fallen out, leaving a flat bottom of tiny ice crystals.
6:47 PM. Altocumulus floccus virgae. Another example of how the top of a storm, as here, can be composed of droplet cloud while the ice that forms in it falls out below. Here, the extreme dryness underneath the Altocu prevents long trails. The ice crystals wither so that they have almost no fallspeed soon after they have fallen out, leaving a flat bottom of tiny ice crystals.  When you see tiny cloudlets like this spewing ice, you KNOW that the temperature has to be extremely low, and colder than -30° C (-22°C) would be a good starting guess.  Actually, guessing “-31.3° ” would be more impressive to your friends or neighbors….   It was a pretty scene, that’s for sure.
5:37 PM. Pretty iridescence occasionally erupted in newly formed Cirrocumulus, newly, as within seconds or in the last minute when the cloud droplets are extremely tiny, less than 10 microns in diameter. You don't see iridescence in clouds with droplets much larger than that.
5:37 PM. Pretty iridescence occasionally erupted in newly formed Cirrocumulus, newly, as within seconds or in the last minute when the cloud droplets are extremely tiny, less than 10 microns in diameter. You don’t see iridescence in clouds with droplets much larger than that.  And, it has to be pretty much overhead to get the best views.  Hope you saw those yesterday.
5:41 PM.
5:41 PM.
5:43 PM. ??????? These are little cloudlets of ice up at Cirrus levels, but it looks exaclty like a field of normal Altocumulus to the ordinary eye. "Altocumulocirrus"?
5:43 PM. ??????? These are little cloudlets of ice up at Cirrus levels, but it looks exaclty like a field of normal Altocumulus to the ordinary eye. “Altocumulocirrus”?  Without doubt this “ice” composition would be contested by other observers.  However, cloud-maven person’s interpretation should be used.  Now it is likely that the ice in these clouds first formed on what we deem as “cloud condensation nuclei”, and it might be likely that water saturation was reached.  But, if there was an instant of liquid, is certainly transitioned to ice in seconds since the temperatures at Cirrus levels were well below -40° C.   I don’t believe this was at the same level as the Altocu shown in the beginning of this writeup, yet it wasn’t as high as the highest Cirrus yesterday (up around the -50° C level).
6:07 PM. An example of how complicated the cloud scene was yesterday. The whitish clouds in rolls were icy cirriform clouds, and the delicated clouds were HIGHER Cirrocumulus and Cirrus. Cirrocumulus yesterday was indeed where most cloud schematics put it, at Cirrus levels, though probably half the time its in the mid-levels were Altocumulus clouds reside. So, with Altocumulus-like clouds at Cirrus levels and Cirrocu on top of Cirrus, it was really a crazy cloud day yesterday.
6:07 PM. An example of how complicated the cloud scene was yesterday. The whitish clouds in rolls were icy cirriform clouds, and the delicated clouds were HIGHER Cirrocumulus and Cirrus. Cirrocumulus yesterday was indeed where most cloud schematics put it, at Cirrus levels, though probably half the time its in the mid-levels were Altocumulus clouds reside. So, with Altocumulus-like clouds at Cirrus levels and Cirrocu on top of Cirrus, it was really a crazy cloud day yesterday.  At the very top of this photo were Altocu that were immediately ice clouds that might have comprised a separate third level of clouds.  Need a Lear jet to get there fast to resolve these many guesses.
5:07 PM. Jumping around in time.... These were some of the best scenes yesterday IMO, those oh-so-delicate patterns in those cold Cirrocumulus clouds, ones that transitioned to Cirrus clouds downwind.
5:07 PM. Jumping around in time here…. These were some of the best scenes yesterday IMO, those oh-so-delicate patterns in those cold Cirrocumulus clouds, ones that transitioned to Cirrus clouds downwind.
5:08 PM.
5:08 PM. Same patch Cirrocu.  Note Cirrus forming in the lower portion of this photo, once Cirrocu.  BTW, all power lines should be placed under ground.
2:29 PM. Amid some real Cumulus fractus was some Cirrus "cumulus mimicry" I've termed "Cumulo-cirrus". Can you spot the fakes at Cirrus levels? Its pretty hard.
2:29 PM. Amid some real Cumulus fractus was some Cirrus “cumulus mimicry” I’ve termed “Cumulo-cirrus”. Can you spot the fakes at Cirrus levels? Its pretty hard.
2:29 PM. OK, I give up. Here's a zoomed shot of Cumulus fractus mimicry by clouds at Cirrus levels. Might have been some droplets, too, before converting to ice.
2:29 PM. OK, I give up. Here’s a zoomed shot of Cumulus fractus mimicry by clouds at Cirrus levels. Might have been some droplets, too, before converting to ice.  These kinds of clouds suggest significant turbulence at this level, as would be in a regular Cumulus fractus cloud.

The weather way ahead

Still looking for that chance of rain before July….  haha

Troughy conditions will actually recur aloft over us over the next few weeks it seems, which means slight chances of rain, but periodic cold fronts passing by, mostly dry ones.  Best chance for rain still seems to be around the 20th, plus or minus a day or two, even though mod outputs have backed off that scene.  But, we have our spaghetti that tells us the models will likely bring back that threat around the 20th, even if some individual runs show nothing at all or only close calls.  We shall see if this interpretation has any credibility at all, won’t we?

Of note, Cal having big April in rain and snow after the gigantic January and February accumulations!  Looks like they’ll continue to get slugged by unusually strong storms, off and on, for another couple of weeks.  Water year totals are going to be truly gigantic.

The End

Catalina/Sutherland Heights gets its own hourly predicted weather from the U of AZ

On this station plot map for the Tucson area, generated by the University of Arizona’s Hydro and Atmospheric Sciences Department, now has a point for little Catalina/Sutherland Heights!   Check it out.  Sample map below.  Now you can see how our predicted weather varies with those points around us over the next few days.  How great is that?Ann Catalina:Sutherland Heights stationSome rain from our incoming cold front is just about here as a line of showers approaches from the west.  Hoping now for a tenth of an inch is all.

Yesterday’s clouds

Had some nice scenes late of little Altocumulus castellanus shedding light snow showers or “virga.”

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6:01 PM.
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6:01 PM. Looking at this line farther downwind, you can see, maybe, that its converting to ice on the far right. So, these Altocu must be awfully cold, at least -25° C I would guess. Estimated bases are at about 18,000 feet above the ground.
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Also at 6:01 PM. Here you can see that those little tufts of water have completely converted to ice down stream (lower right). For this to happen at Altocumulus level takes very low temperatures. Now I will look at the NWS balloon sounding and see if I have come close at all to this height and temperature. Its gotta be way up there.
Ann 2017032300Z_SKEWT_KTUS
The TUS sounding launched from the U of AZ yesterday around 3:30 PM. I had not seen this until just now! But you can see that the height and temperature estimates were pretty close. Height above Catalina was about 18,000 feet, 21,000 above sea level.
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6:51 PM. The clearing before the storm. Those higher clouds departed, and the lower moisture and clouds that will comprise our chance of rain, began to appear on the NW horizon. Can you see that those tops have ice in them?

 

The weather ahead and way ahead

March. a lamb upon entry,  will roar on the way out.  While only a little rain will likely fall today, several more troughs are in the works, during the next ten days and they are looking much more potent than today’s trough and front passage, probably bringing cold enough air that some people will start complaining about how cold it is; probably me.  Looks, too, like abnormally cool weather will cruise right in to the first week or two of April.  Bye-bye heat!

The End