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!
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!!!!
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.
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!
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.
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 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.
I thought you’d like to read this (Peru’s Niño), forwarded to me by Niño expert, Nate M. Pretty incredible to read about what is happening down there in the wake of the Big Niño of 2015-16, which really turned out to be more of a couch potato in terms of weather production in the Great SW.
But, all this winter, along the Equator near the coast of South America, there has been something we used to call an “El Niño”, but is downplayed or ignored these days because of a new definition that seemed to explain more weather when it occurred, “Region 3.4” a large zone along the Equator WAY out in the Pacific rather than something near the South American coast (that zone now called, “Regions 1 and 2”), as nicely illustrated by NOAA here.
But what has been the effect of what we might call the “Classic Niño”, a warm strip of water along the South American coast, one that doesn’t extend too far into the Pacific? “Read all about it”, as they used to say. Its pretty remarkable.
And here’s what the SST field looks like. Its boiling down there off South America! (Speaking figuratively, of course):
Peru’s Niño can be thought of as a “classic Niño”, the ones written about in the decades before about 1990 or so when the definition of what constituted a NIño (or Niña) was expanded and delineated more sharply among several definitions that were floating around. We ended up focusing on a region WAY out in the Pacific Ocean called, “Region 3.4” that SEEMED to explain more over the prior years.
What’s so interesting about this is that the “Classic Niño” has been underway pretty much all this winter, and we’ve had, especially in California, a classic Niño response; that is, abnormally heavy precip farther down the West Coast that no one anticipated.
Well, the correlations with Cal precip and “classic Niño” occurrences will take a huge jump upward after THIS winter!
End of Statement (hand-waving) on Niñoes.
Local weather statement: for immediate release
Cooler, fluctuating weather foretold here for that latter part of March, I don’t know how many weeks ago, is on the doorstep after the long, anomalously hot dry spell. Poor wildflowers have been suffering, too, fading, looking a little stunted after a great beginning, one rivaling the great displays of 2010.
All of the local weatherfolk are on top of this now, and so no point recasting that stuff. HECK, you can go to Weather Underground1 and get as “good as can be” forecast for Catalina (Sutherland Heights) out to ten days! And, there’s nothing worse for a weather forecaster with forecasting in his blood, than to be excited about an “incoming” and when you mention it to a neighbor he replies, “Yeah, I heard about that already. Supposed to get a quarter of an inch.” There is no air whatsoever in the “balloon” after that. So, if you have a weather-centric friend who says something about the upcoming weather, pretend that you haven’t heard about it yet, “DON’T say something as hurtful, as “Yeah, I heard about that already.”
So, here, we go the long route because most weatherfolk are afraid to go too far into the future because its often WRONG. Our models tend to lie a lot after about even a week, so only the brave go out even ten days!
However, here, we go out as much as two weeks and more because its not a truly professional site but rather want to get something out there earlier than other people, sometimes called a “scoop” in the news and weather business. That’s why our motto here is, “Right or wrong, you heard it here first!” Furthermore, if a longer range forecast posted here is WRONG, you won’t hear about it anymore!
Cloud maven person will say this about the first incoming of several fronts: comes in early Thursday morning, its strong! Rainfall potential: 10% chance of less than 0.12 inches, 10% chance of more than 0.75 inches. Best of those is the average, or about 0.4350 inches in this one. It has great POTENTIAL to be a soaker, but mods have been all over the place; hence, the large range of potential amounts. At least some measurable rain seems to be in the bag, a paper one please, because plastic is insidious. Note, CMP’s forecast is more generous than that found in WU’s latest forecast for Catalinaland.
The weather WAY ahead, unprofessionally so
Let us look beyond the professional forecasting limits to April:
We know we got several storms/fronts zipping across AZ as March goes out like a lion, but what about April?
Looks like that pattern will continue into April with temperatures below normal for the first part. The end of the unprofessional forecasting portion of this blog, though we do have our NOAA spaghetti to hang our umbrella on…. Check it out for about two weeks ahead.
Some clouds recent clouds, including a couple from yesterday
———————– 1Although “Weather Underground” might sound like an org has a radical origin, maybe something left over from the late 1960s, this particular one was NOT formed by 60s “weatherman” terrorists like Bill Ayers and Bernadine Dohrn (the link is for those of you who may have set trash cans on fire, as happened at San Jose State to protest the Vietnam War, to look back at those days in horror or nostalgia; take your pick) , but rather by genuine weather geeks (haha, I count myself among them, those that can’t get enough of weather, there can never be too much, like the guys mentioned in this “Cloud City” article.)
Doesn’t look promising for much rain here in Catalina in March, however. No rain in sight through the next 10 days at least.
Let’s check our 7 inches with what’s happening upwind, say, in CALIFORNIA, and see if there’s been any drought relief there, through February, via the CNRFC:
As you are likely to know from many media stories last year, Cal was in a drought siege of five straight years, with but got a little relief last year in the northern part thanks to help from the giant Niño, one of the strongest ever.
Alas, it was one that failed to deliver as the big rain producer for the south half of Cal and the SW in general as was expected.
In case you’ve forgotten how bad things were in Cal, let us look back at what was being said, those horrific appearing drought maps, and also how hopeful were were at the time that the Big Niño would take a bit bite out of drought. This is a really good article:
Then, when the Big Niño faded away like maple syrup on a stack of buckwheat pancakes last spring and summer, we were surely doomed for more dry years. And, for a time, the dreaded cold tongue of water in the eastern equatorial region, the so-called, La Niña, started to develop, which would be no help at all for a good rain season like a Big Niño is, usually.
The Niña faded away, too, to nothing as the winter went on, so we really didn’t have much going on in the tropical Pacific to help us figure out what kind of winter rainfall regime we were going to have om 2016-17. Not having anything going on meant winter rainfall could go either way, a difficult to figure out situation for season forecasters.
In retrospect it is pretty astounding how big a signal must have been out there SOMEWHERE that this winter was going to be one for the history books on the West Coast in general, and in particular, for Californians. Californians saw their drought chewed up and spit out in a single winter, including snow packs so high the height of some mountain peaks have been revised. (I’m kidding.)
No one saw such an astounding winter coming.
This winter sure makes one think of the QBO (Quasi-biennenial Oscillation, one up there in the Stratosphere where there’s almost no air (haha, well, practically none)… Did the QBO have a role in this astounding winter; was there a delay in the effects of the Big Niño even without a bunch of convection in the eastern Pac tropics? Doesn’t seem that could be right…
But, William “Bill” Lau, U of Maryland scientist, reported some statistical evidence of such a lag way back in ’88 due to a QBO connection of some kind and ENSO, no physical cause could be discerned, however, not yet, anyway. Lau, 1988, is reprised below for readers who want to go deep:
I guess “billows” (“undulatus” in cloudspeak) two days ago in the late afternoon wasn’t enough of a sign that the weather was changing. Yesterday we had fast moving Cirrocumulus with rainbows in it, and as the sun was setting, “jet streak Cirrus”, a line of Cirrus clouds often seen in the very core of high altitude, powerful jet streams passed overhead.
How hard was the wind blowing up there in that Cirrus last evening? Oh, our Tuscon balloon sounding, lifting off around 3:30 PM, going up about a 1000 feet a minute to, indicates that the max wind up there at Cirrus level was 146 knots (just under 170 mph)! Yikes. Poor balloon. Must be in France by now.
The storm has been a bit of a disappointment in rain production. We’ve only logged 0.22 inches1. Not as much as foretold here, 0.33 inches, but that forecast was a better prediction than by “Weather Underground Robotics” (0.58 inches). Its great to beat a robot!
We had another sign yesterday in the fastest moving Cirrocumulus clouds I think you’ll ever see around here (about 100 mph), ones at just 18,000 feet above sea level, 15 kft above Catalina: rainbows of color near the sun called iridescence (also called “irisation”). Here, as is the norm here, are a few too many shots of the same thing2.
The colors themselves, of course, don’t warn of something about to happen, but the fast movement from the southwest did; a powerful jet stream is over you. That strong stream, the result of temperature gradients in the atmosphere, is dividing deep warm air from deep cold air, and steers the alternations of high and low pressure centers, and with those alternations of lows and highs along the jet stream, air is drawn from different latitude zones and the boundaries where those different masses of air meet at the surface, is called fronts. Here, such as last night, its nearly always cold ones.
The rest of the day was pretty exciting, the wind arising suddenly yesterday morning, along with our usual great visibility, and darker blue wintertime skies, made the clouds stand out more.
The sky at last, considering the power of the trough approaching, FINALLY began to fill in. Started looking around for the first sign of ice having formed in these clouds as the air aloft became cooler. Along with this filling in by Cumulus and Stratocumulus clouds, some sun highlights began to appear on our mountains, contrasted by the darkening skies above.
Eventually our jet streak Cirrus provided the background for another great sunset scene:
Today’s clouds and weather
From that map above, you’ll see that there’s a “tail-dragger” trough still to the west of us and about over Sandy Ego (haha). That’s going to keep the air over us extremely cold, and with some sun, the Cumulus clouds that arrive are expected to have tops colder than -15 to -20° C, plenty cold enough for the formation of ice.
Ice means precip, snow up there, rain down here in spots. So, we could still pick up a few more hundredths if a shower happens to drop by. The chance of isolated very light showers in the area is 100%, but no one can tell you if one will actually land on us. You’ll have to be watching, mostly after 12 noon. Look to the west toward the Tortolita Mountains, terrain that ought to spawn one or two of those.
Looks like a longer dry spell ahead; several days to a week, maybe more.
1CoCoRahs gauge, btw. NWS-style gauge had only 0.20 inches, likely due to enhanced wind loss associated with my collapsing prickly pear protector. 2 I was driving and had to park and jump out of car to get these. You only have seconds or maybe a minute or three to capture stuff like this.
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.