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:
I thought you’d be pretty happy when you saw this, as I was.
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
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:
——————————————- 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.
I could literally hear the cameras clicking all over Catalina and Oro Valley as these patterns showed up, moving in from the southwest as the increasing numbers of cloud-centric folk lost control of themselves. Reflecting that general loss of control, which affected yours truly, too many photos will be posted here. Below holey clouds with icy centers, but not ones caused by aircraft:
And look closely at the fine patterns, lines and granulations in these shots! Truly mesmerizing.
But what’s missing in this photo above? There was no iridescence seen around the sun where we normally look for it suggesting that those Cirrocumulus clouds nearest the sun were composed of ice crystals, and not tiny droplets. Iridescence is rarely seen next to the sun due to ice crystals because they are usually the result of the freezing of existing droplets, that then grow rapidly as ice particles to sizes too large to produce diffraction phenomenon close to the sun. Where’s my Lear jet, so’s I can confirm these speculations?!! I would very much like to have one on “stand by”, in case I think of something. Below, a wonderful example of no iridescence even though newly formed clouds are by the sun:
A jet runs through it
Or so I thought. In this chapter of cloud-maven.com, we inspect the photos of a commercial jet flying at or near the level of these clouds and determine what happened. I was quite excited to see this happen because we would now determine whether there were any liquid droplets in what to the eye of the amateur cloud watching person would be a liquid droplet Altocumulus clouds. Here the size of the elements are just a bit too large to lump it into the Cirrocumulus category, if you care. So, with heart pounding, took this sequence of photos:
Let is go zooming:
By the way, if you caught it, there were a couple of standard, aircraft-produced, “hole punch” clouds at the very upwind, formative portion of this patch of clouds before it got here. These photos pretty much prove that the Cc at the formative end at that time was composed of highly supercooled droplets and that the passage of an aircraft produced ice, that caused a fall out hole.
Once again we had a brief period of optical fireworks, as a rare “circumzenithal arc” developed overhead of Catalina in some Cirrus strands. Hope you saw it and bragged about it to your less observant friends. After saying that, follow it up in a moment of feigned reflection, speaking to no one in particular, with a comment about “how sad it is when people don’t notice the beauty in the world around them.” Your friend will appreciate what a sensitive person you are. That would be great!
Here are the scenes so many missed because you only have SECONDS to see them light up, peak out and disappear (but I saw it!):
Whew, that was pretty much the climax of this event. Began to relax. calm down, as the possibility of seeing more “arcs”, began to fade. No more Cirrus was upwind.
Most of these I have seen have been due to aircraft-produced ice particles (“APIPs”, as named by Rangno and Hobbs way back in 1983, J. Appl. Meteor.), i. e., contrail like events produced by aircraft that occur at much higher than expected temperatures in “supercooled” clouds.
No Altocumulus clouds were around this line of Cirrus uncinus clouds at the time this passed over, though there were plenty around, however. Likely this was produced upwind by an aircraft in Ac clouds, and the Altocumulus droplet clouds just evaporated.
These aircraft produced ice clouds start out having prodigious, unnaturally high concentrations of ice, thousands per liter, and that in itself would lead, due to the competition of vapor among them, to tiny, pristine ice crystals like solid columns that would refract the sun’s light. So, that’s my thought on the origin of this line of Cirrus uncinus, the line itself raising suspicions about its origin. It extended much farther than shown in these photos, and was intermittent, likely reflecting where the Altocu was, and where there were holes in the coverage.
Then this, looking straight up when CMP first noticed it because he wasn’t paying attention:
A few minutes later, as it moved away:
What happened? How cold were these Altocumulus clouds?
(Answers printed upside down below).
There were more, off in the distance, too.
Here are a few more shots of this phenomenon:
Now, we’re really quitting because I have other things to do, ones that have to be done, like discovering why our attic has so many rodents in it? Well, one, every so often, dammitall. Why is life one problem after another?
Answers not printed upside down instead:
It was an ice canal created in a highly supercooled layer of Altocumulus perlucidus. How cold? Whenever you see one of these in a middle cloud like Altocumulus, you can guess that its colder than -20° C. They’re rarely seen in warmer clouds. The TUS soundings suggested this layer was between -25° and -30° C. It mostly was ice free, bur regions of some slight (natural virga) were seen,
It was probably created by a jet, though the rarer prop aircraft can’t be ruled out. Seems to be associated with cooling around prop tips or some say over the wing cooling momentarily below around -40° C, though visually I would offer that its from the water-loaded exhaust, at least in jets, rather than air cooled as it goes over the wing.
Yesterday, after an ordinary beginning,, finished in a spectacular, if likely artificial way. Let us work our way through yesterday’s cloudulations:
Later that morning…..
But let’s go zooming up to flight level and take a closer look for a second:
Now, where was I? Got mammatus on my mind again. I love mammatus so much… Oh, yeah, that sunset yesterday…..
And the sun did its job….producing one of the greatest sunset scenes we’ve seen in a long time, even if phony (haha):
Finally, let look at the TUS sounding for last evening, see how cold those Ac cloud were with the ice trail in them:
The astounding thing here, something that goes against everything I believe about clouds, is that it is indicated that the Altocumulus, lacking much natural ice, was at -30° C! Yikes! No wonder aircraft were producing ice trails and stuff yesterday afternoon.
You have to conclude there were almost no natural “ice nuclei” up there at, oh about 24,000 feet above sea level. This is not the first time for such an occurrence of liquid clouds sans much ice at low temperatures1, but they are rare IME. This would never occur in a boundary layer cloud, that is, one where material from the earth’s surface is getting into the clouds, like the omnipresent dust, or biogenic ice nuclei.
The weather ahead
Some “fantasy” storms with rain in them for Catalina, are now seen on the model predictions beyond a week. Spaghetti is favoring this new development now. So, something to keep an eye on.
The view from here? Precip here is “in the bag” because going on subjective feelings, I really want to see a good rain here!
1The famous John Hallett said he saw an Altocumulus lenticularis sans ice at -35°C in a conference preprint! Rangno and Hobbs (1986) claimed to have detected droplets in Altocumulus like clouds at the top of a storm on the Washington coast at -44°C. Their claim, first published in a conference preprint, was later rejected by the J. Atmos. Sci.
As the morning wore on, the Altocumulus deck faded away, moving east, and we were left with some Cirrus clouds, but what kind?
Well, that was it for photography yesterday.
Doesn’t seem to be any reliable indication of rain in sight. Oh, sure, rain here pops up in the models almost every day, but its about 12-15 days out. As the model gets closer to the day it predicted rain, it seems to go away like the “water mirage” on a hot paved road; always ahead of you, but you never get to it. We’ve had some major rains indicated in the models as of a few days ago, but spaghetti was never very high on those events (clustering those crazy lines in a trough over us), so it wasn’t even worth mentioning.
Many strange1 and wonderful sights were seen yesterday; I could feel the excitement out there as one cloud microstructural mystery after another regaled our Catalina skies.
How cold are these clouds? Lets look at the TUS sounding, launched at about 3:30 AM yesterday morning.
That bank of Altocumulus was racing at more than 50 mph toward Catalina, and so it got here in a hurry. And, as it got closer, it was also getting more into some airways at that height, possibly descents into PHX since the height of those clouds was below normal jet cruising levels at 23,000 feet Above Sea Level.
Now for the aircraft effects. Hardly a few minutes go by before aircraft began marking up this cold Altocumulus layer. Notice that it doesn’t seem to be producing much or any ice on its own, making aircraft inadvertent seeding lines and holes where tremendous numbers of ice crystals are generated immediately present. Here’s the first of many:
Heading for Catalina, this:
Here’s the south end of that ice canal:
Looking straight up at the icy heart of a hole punch region caused by an aircraft. I am sure you have never done this before! This is gonna be a great blog with all these new things for you!
As the south end of the original ice canal began to enter the refraction zone for simple ice crystals around the sun, usually at the 22° degree halo position, things began to light up with a particularly bright circumzenithal arc (more often observed on a halo) or colorful (in this case) partial “reverse halo”. The colors (iridescence) due to the refracting of light within very small ice crystals. Normally iridescence is seen near the sun in Cirrocumulus clouds or the then edges of other droplet clouds. Very exciting.
Then this strange sight:
The day closed out with a lower layer of Altocumulus moving in, this layer, according to the TUS sounding, at “only’ -17° C, and little ice detected. Below, at 2:09 PM:
U of AZ mod thinks so light rain will develop around here in the mid-later afternoon.
1“stragne” above, originally an inadvertent typo, but left in place as another cheap trick to get draw the curiosity of readers who might wonder what stragne is.
“Too many pictures, for one site…”, a continuing theme here1, to paraphrase “? and the Mysterians1“.
Two stations near Picture Rocks reported 1.25 and 1.35 inches, respectively, so some major rain fell fairly close to us. You can see the amount arounds around the State or here at the Banner U of AZ rainlog,org site.
Below your October 8th, 2016 cloud day, a Saturday in which the author’s former company fubball team, the Washington Huskies, spanked the Nike University of Oregon Duck, 70-21, ending years of futility against the billionaire’s sports teams. Too bad Washington multi-billionaire Gates is more interested in saving the world instead of helping the Huskies get better in sports like Phil Knight does with The Duck there in Duckville, OR….
Oh, well, off task there for a minute. I’m back now!
Now, here where the excitement begins. Recall Mike L. and Bobby Maddox, both super experts concerning convection, called for severe storms and large hail today due to what the models were showing in the vertical wind profile and the amount of moisture available. Below, we start yesterday chapter of convection, and see where it leads.
1If you don’t believe ? said something like that, go here
The clouds were somewhat of a disappointment yesterday, not the stupendous photogenic day CM was expecting.
Maybe CM is total fraud, gets Big Oil funding and should be investigated by Rep. Grijalva as other weather folk are, like the great Prof. and National Academy of Sciences Fellow, Dr. Judy Curry, a friend, and about whom I say on a link to her blog here, and from this blog’s very beginning, “The only link you will need.” I said that because Judy2 is a top scientist, and is eminently fair in this polarized issue.
I am in real trouble! Will remove that link immediately1 before our very own “climate thought enforcer”, Demo Rep. Grijalva, AZ, finds it using a spy bot! No telling how far down the influence chain it will go, maybe all the way down to here, where there is virtually no influence!
Back to clouds…….
Only late in the day did the delicate patterns expected to happen ALL DAY appear, again, with iridescence, always nice to see.
The media, Bob, and our good NWS, of course, are all over the incoming rain in great detail. In fact, it will take you half a day to read all the warnings on this storm issued by our Tucson NWS.
So why duplicate existing information that might be only slightly different than the prevailing general consensus on the storm amounts, and then maybe be investigated for going against a consensus? No, not worth it. Best to be safe, not say things against The Machine. (OK, maybe overdoing it here.)
In the meantime, the upper low off southern Cal and Baja has fomented an extremely strong band of rain, now lying across SE Cal and the Colorado River Valley where dry locations like Blythe are getting more than an inch over the past 24 h. Same for northern Baja where some places are approaching 2-3 inches, great for them. You can see how the rain is piling up in those locations here. In sum, this is a fabulous storm for northern Mexico and the SW US, whether WE get our 0.915 inches, as foretold here, or not! Rejoice in the joy of others. Looking for an arcus cloud fronting the main rainband, too, that low hanging cloud in a line that tells you a windshift is coming. Still expecting, hoping, for thunder today to add to the wind and rain drama.
Also, the present cloud cover, as the trough ejects toward us, will deepen up and rain will form upwind and around here as that happens, so it won’t JUST be the eastward movement of the existing band. This means you might be surprised by rain if you’re outside hiking and think the band itself is hours away. Expecting rain to be in the area by mid-morning, certainly not later than noon, with the main blast (fronted by something akin to an arcus cloud) later in the day. OK, just checked the U of AZ mod run from 11 PM AST, and that is what it is saying as well! Wow.
Finally, if you care, yesterday’s clouds:
Below, just some pretty patterns observed later in the day. Click to see larger versions.
Whew, the end.
1Not!!!!!! I thought this was a good read about this deplorable new stage of “climate thought enforcement” now in progress. It was brought to my attention by climate folk hero, friend, and big troublemaker, Mark Albright. Wow, maybe Mark will be investigated, too! Maybe I should excise his name….
2I remember, too, how cute she was when she worked my lab/office at the University of Washington in the mid-1980s, and thought about asking her out, to detract from a serious commentary here. She was a Penn State grad student, not a U of WA employee; still, to ask her out would have been untoward. A human commentary like this, one about feelings and things, help boost blog attendance.
If you thought those high clouds were moving faster than usual, you were right. The winds were about 120 mph at that level, about 28,000 feet above sea level, and just over 150 mph a few thousand feet above that level.
You may have noticed two things, if you are good, that there were repeated formations of delicate Cirrocumulus clouds, likely starting as liquid drops, but quickly transitioned into Cirrus. Sometimes, it was just flocculent Cirrus the whole way to us from the west.
The second thing that you may have noticed was that there was always an upwind clearing zone that remained stationary until late afternoon when it finally passed overhead. Yesterday’s high clouds formed at that back edge.
How can you tell that the upwind edge of that sheet of clouds was initially composed of liquid droplets, but then froze naturally within a minute or three as it jetted downstream?
Perform an experiment to demonstrate the two phases.
In this case we will have an ice producing aircraft fly through both regions, the droplet region, and also the region where no droplets exist because they have frozen and are growing larger and larger as ice crystals.
What will be the predictable result of two ice-producing aircraft flying through these two different phases?
In the liquid cloud region, an ice canal will develop as the appearance of ice in a droplet cloud results in the evaporation of liquid droplets, the molecules of vapor from the evaporating droplets provide “food” for fattening ice crystals, where “deposition” takes place. Under a microscope you would see the crystals getting larger, growing extensions; you would not be able to see the molecules producing that, of course.
The result of our experiment, something you likely will never see again in my lifetime:
Was holding breath, thinking about that CV enhancement, waiting for the TUS sounding, which was already in the air when these last few photos were taken, and, more importantly, it was going up near where the clouds were forming, so the moist level intercepted and its temperature would be pretty accurate for this shots. Now, if its -40 C, oh man, we got a pub! -36 C, maybe. Temperature greater than about -35 C? No pub, well, except here, which is something. That’s because liquid drops at temperatures between -30 and -35 C have been reported by remote sensing and aircraft repeatedly. Nature abhors forming an ice crystal in clouds without going through the liquid phase first.
Within a couple of hours the TUS sounding was in, and here it is:
I wasn’t going to get a journal pub. I thought about that guy that thought he was going to win the Nobel Prize…..and I know now how he felt.
Now about those pretty patterns, by Simon and Garfunkel. Enjoy.
Jet core at 18,000 feet now passing overhead and DRIZZLE or very light rain from warm processes now (4:15 AM) evident on the Catalina Mountains. The passage of that jet core at that level (500 millibars) seems to be an almost black-white measurable rain or no rain discriminator in the Southwest US, so as that happens right now, chances of some measurable rain are good. Still not expected to be more than 0.25 inches, but will now at least be 0.01!
The low clouds are pretty shallow now, and, if they rain, shallow clouds with tops warmer than -5 C (23 F) have to be pretty clean for that to happen. Clean clouds is got bigger droplets, ones that reach the Hocking-Jonas threshold of between 30-40 microns in size and can collide and stick together forming still much larger drops that collect more and more tiny cloud droplets, kind of a chain reaction, as Nobel Laureate in chemistry Irving Langmuir described it back in 1948 after he got interested in clouds and rainmaking.
However, the “collision with coalescence process will be short-lived as cloud tops go up to well below freezing level this morning, and real rain falls (as is happening now (7:18 AM) down in TUS and to our NW.
Measurable rain should be just on the doorstep, and it will have to develop in upwind clouds as they approach us and the air begins to rise as it goes uphill from the lower deserts and encounters the Catalinas’ there isn’t much in the way of radar echoes upwind of us now.
The development of rain in clouds as they approach us in marginal rain situations like this one is not terribly unusual. Sometimes, as a friend pointed out, new echoes in deepening clouds can appear over and over again near where I-10 runs to the SW and W of us in a purely orographic situation.
This is what CMP is hoping for, and the result of that might be a tenth of an inch or more.