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 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.6:45 PM. A very narrow line of Altocumulus castellanus and floccus virgae approaches Catalina.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. 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. And, it has to be pretty much overhead to get the best views. Hope you saw those yesterday.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”? 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. 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 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. 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. 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.
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.
10:54 AM. The fist of weather is used as a prop to indicate that these colors are forming a ring around the sun. Usually you try to find a light standard somewhere…maybe a “gopro cam on a stick” might do it. Just don’t look at the sun when you do this.10:57 AM.10:57 AM, pulling back some for perspective. As we often say here, “so pretty.” And look at how tiny the granulation is in this Cirrocumulus cloud is!
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.
7:56 AM. Looking to the west at a scattering of Stratocu patches.7:57 AM. Highlight on the hills above Saddlebrook. Stratocumulus overhead.8:42 AM. This patch of Stratocumulus was the result of a lift zone that often produces clouds headed our way in southwesterly flow. The difference here is how limited in size this patch was allowing you to see where that lift zone was. Downstream, though, descending motions creamed this cloud, one that sat there most of the early part of the day. Usually a whole layer is over us, with a clearing visible toward the SW horizon.11:02 AM. Still out there pretty much near the same spot, still limited in size. Wind here now 20-30 mph with stronger puffs.
11:40 AM. By this time it had shifted closer to us, still forming on the southwest end, dissipating at the downwind end where the cloud is so ragged due to mixing with dry, descending air.12:42 PM. Creeping closer, but still a standing wave, dissipating as it came toward us. It was about this time that it disappeared, the sky becoming more complex with no simple standing waves.
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.
1:55 PM. Stratocumulus clouds bank up against the Catalinas, Samaniego Ridge.2:03 PM. While Stratocumulus banked up against the mountains, huge temporary clearings occurred elsewhere. Notice how shredded the tops of these clouds are and how the tops lean to the right. They’re revealing the great increase in the wind with height, and yet, how dry it was above this layer (that, by the ragged cloud tops mixing with the very dry air just above them.)3:38 PM. Here comes the Jet Streak Cirrus! Also about this time, the frontal windshift line, marked by low scud clouds in the cold air, began to appear on the NW horizon. It was an exciting moment. Here we go! FROPA within a coupla hours maybe. Well, took longer than that….3:52 PM. A little ruffle of Cirrocumulus leads the advance of the jet streak Cirrus.4:11 PM. Cloud line forming above the frontal windshift line. Was progressing this way at this time, but was to stall, maybe back off.4:11 PM. Zooming, floating over Saddlebrooke, this close up of our FROPA and windshift line. Ended up backing off, dissipating, maybe reforming later after dark. These lowest clouds form in the colder air associated with the windshift line at the nose of the front as the moist air ahead of the front mixes with it and is lifted. We see this with most of our incoming cold fronts, and in our summer thunderstorms. The best cases form “arcus clouds”, a solid line just above and behind the windshift at the ground. These kinds of ragged clouds, in cloudspeak, are called “pannus.” Was pretty excited here, as no doubt you were, that FROPA (frontal passage) was imminent, might happen within the hour. Nope.4:40 PM. In the meantime, our jet streak CIrrus, above the Stratocumulus clouds, moved overhead, the clearing behind this thin band leading to some memorable fading sun highlights on the Catalinas.5:40 PM. No words needed.5:43 PM. “Fading sun and rain gauge.” Another one of those exceptional scenes you won’t find anywhere except on this blog. Tell your friends. A small mammal, termed a “packrat” is decimating my prickly pear wind protection for this gauge! A lot of rain loss occurs due to wind. drops missing the collector! It very upsetting to see this happen.5:43 PM. Even the often despised teddy bear cholla can be so beautiful in this fading sun, the spines capturing it so well.
Eventually our jet streak Cirrus provided the background for another great sunset scene:
5:56 PM.
A 300 millibar (about 30,000 feet above sea level) with an IR satellite image for yesterday at 5 PM AST. The Cirrus layer extended from about this height to around 35, 000 feet above sea level. according to our TUS balloon sounding. Arrows denoted the jet streak Cirrus cloud thatpassed over us, enhanced in the downwind region of the Baja mountains. Note that the wind at San Diego max wind was even slightly stronger than our wind max was at this level at152 knots. This map is the courtesy of the University of Washington Huskies Weather Department.
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.
The End
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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.
First, you should always begin your day, not with the breakfast of champions, but by reviewing the prior day’s clouds in the University of Arizona time lapse movie. Here’s what you will see:
Lots of Cirrus, varies species, Altocumulus, Cirrocumulus, a high temperature contrail go through some Cirrocumulus just after 4 PM, and flocks of medium-sized Cumulus clouds emitting ice.
First, one interesting, but inexplicable Cirrus scene. I know you were likely going to ask Mr. Cloud Maven Person, “Hey, what gives here?” I get a lot of calls like that1.
1:15 PM. That tuft of Cirrus on the right seems to have trails of ice falling out then coming together, almost like they missed each other and want to be together as snow trails until evaporating away. There is no explanation for this2 so I will next post a distraction. (Remember, when you can’t explain something, and this is a life hint, you can either talk around the question without answering it, beginning with, “I’m glad you asked me that question…..” when you’re lying and really NOT glad, or launch a distraction. Here, we launch a distraction.
“I don’t know how that happened; let look at a flower instead”:
Seen yesterday morning on a dog walk, evening primrose. Pretty restful image; problems gone…
In the meantime, after being flustered over a cloud in the early afternoon, those Cumulus clouds aroiund, only two or three thousand feet thick were beginning to snow away, first way off to the south of us, then downstream of the Cat2 Mountains.
Here is the rest of your interesting and learningful cloud day yesterday:
7:17 AM. Riff of Altocumulus castellanus/floccus to the north. Remember in Cloud Maven’s Person’s poster-sized cloud chart it says when you see this cloud it could rain in 6 to 196 hours, as it does for all the cloud formations in it.7:18 AM. Iridescence in a patch of Cirrocumulus, indicating that the droplets comprising it were very tiny, less than 10 or so microns in diameter (one tenth the diameter of a human hair). It could rain in 6 to 196 hours when you see this cloud….9:43 AM. Cirrus, various species/varieties overspread the sky. Blockage of some Cirrus here by a bird of some kind, lower center.
Moving ahead…..
1:14 PM. The cloud-maven cloud indicator blimp was positioned to draw your attention to some building Cumulus clouds southwest of us. No ice evident, but was soon after this shot.
2:47 PM. Cumulus complex shows no ice, but its up there inside, as you would have known from looking at other similar-sized clouds.3:02 PM. “Droop, there it is!” Virga, there it is, drooping out just below the farthest cloud bottom downwind end of this cloud stream.3:17 PM. Virga’s pretty obvious now (above that protruding tree in the distance. Cloud that produced this virga likely no thicker than the white backed one at the start of the cloud stream, etimated depth, 2000-3000 feet. Bases, however, were about -8 to -10 C (18-14 F)! Tops, of clouds even that shallow, were really COLD, maybe to -15 to -20 C (down to 4 F)! But you would have guessed this anyway based on the amount of ice coming out of such shallow clouds. Sorry to insult your Cloud Maven Junior intelligence..3:23 PM. Getting excited here so zoomed in for you. A sprinkle of rain was likely reaching the ground. Here you can see how cold the cloud bases were since that whiteness in the shaft is snow. Where it has completely melted into rain drops is where the bottom of that whiteness ends, The freezing level is typically about a thousand feet higher than where than whiteness ends below cloud base in steady, not too heavy precip, which is what we have here. Small clouds can’t precip too much. That snow is hanging down about 3,000 feet.4:34 PM. A streamer of shallow clouds forming ice heads out from the south toward Oro Valley from Tucson. Estimated depth, 2000-3000 feet is all.4:34 PM. Zoomed view of some of the ice in this cloud with an education module inserted into the photo, wrecking it some. Concentrations here likely around 1 per liter of ice crystals. If depth correct, the crystal habit will be stellars (“Christmas card” crystals) and dendrites, ones that form between -13 C and -18 C.The TUS balloon sounding (AKA, rawinsonde for technophiles) launched around 3:30 PM AST yesterday afternoon (from IPS MeteoStar). Sounding calculates a cloud base of about -9 C, at about 10,000 feet above the ground (over Catalina). That is cold! Cloud base is just about where the two lines come together at the bottom.5:46 PM. Mock sun or parhelia; couldn’t tell if is was due to the lower ice cloud, or a Cirrus way above. Caused by hexagonal (six-sided) plate-like crystals falling face down. What a great optical phenomena day it was for you, starting out with a nice iridescence!6:25 PM. Sunset photos continue to get later and later. These shallow clouds continued to produce virga into the evening hours.
There’s still water in the Sutherland Wash. Its been running now since the end of January! Amazing.
The End
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1FYI, this is a lie.
2I suppose someone could posit that “Dark Magic”, oops, “Dark Energy” may have caused those trails to “come together over me” , by Lennon and McCartney. “Dark Magic”, OOPs. “Dark Energy”, dammitall, is invoked to explain a lot of impossible things, like how the Universe blew up from something smaller than the head of a pin (!) and was 200 million light YEARS across in the tiniest fraction of a ONE second. Clearly impossible without magic, oops, Dark Energy. This impossibility was deduced on cosmic microwave radiation measurements at the farthest edges of the Universe as we know it.
However, instead of checking their measurements, cosmos (not Cosmos Topper of early movie fame with Carey Grant, but cosmos scientists that study the cosmos invented Dark Magic, oops, Dark Energy, dammitall again, to explain how something that’s impossible happened.
Recently, cosmos scientists retracted that finding and said their measurements in retrospect were likely compromised by cosmos dust. How funny izzat? Sure, I am a weather man and make a LOT of errors myself, but that cosmos one is pretty big.
Just kidding, cosmos guys, the cosmos is tough. Science mag reported that only 4 % of the visible Univserse is made up of known stuff, 96% (gasp) is made up of Dark Matter (23%), and 73%, of “Dark Magic”, oops again, “Dark Energy”, that stuff that is still thought to be behind the increasingly rapid expansion of the Universe3. That is, 96% of the Universe is composed of stuff we’re clueless about.
3It was originally posited that the expansion of the Universe should be slowing down until around the 1990s, when measurements indicated it was speeding up. Hmmmmm. Will there be a retraction of that claim, too, in our future? Stand by for more measurements. Just kidding, cosmos guys. Try being a weatherman….
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:
6:45 AM. Your sunrise color, thanks to a line of broken Cirrus spissatus. Jet stream Cirrus streak, as a matter of fact, moving along at about 110 mph.9:47 AM. Ruffle of Sc topped Mt. Lemmon, while strange clouds formed just upwind of them. These kinds of shapes suggest an inversion where the air resists further upward movement and a smoothing occurs at the top similar to a lenticular cloud. Photo taken at the Golder Ranch Dr. cattleguard. which really doesn’t work that well, as the neighbors below here will tell you.The 5 AM, March 1st, balloon sounding for TUS.9:53 AM. Looks like a crab with four pinchers. How funny.12:23 PM. Shredding tops of small Cumulus like this indicate that the air is very dry just above their tops, and the shreds racing off to the right, indicate how fast the wind increased as you went upward.2:58 PM. Something is changing here. Notice how the tops are bulging and not immediately being torn into shreds. The air was likely moistening above cloud tops, and the inversion holding the tops back, weakening as our storm gets a little closer.4:19 PM. A line of still larger Cumulus had formed to the west, indicating more moistening and “de-stabilization” of the air. However, the upper low was not advancing toward us any longer and no further development occurred as stagnated, ratcheting up its rainband over eastern Cal and western AZ. The TUS balloon sounding suggested tops were getting close to the normal ice-forming level here, -10 C, the slight inversion on the morning sounding at 13,000 feet above sea level, and the one likely to have caused those smooth morning clouds, was gone.6:07 PM. Just before sunset from near Oracle where we took mom for her BD. The heavier Cumulus clouds faded with the sun. They will arise today!
Below, just some pretty patterns observed later in the day. Click to see larger versions.
3:28 PM. Cirrocumulus began to appear.3:36 PM. Twisted, tortured Cirrus (fibratus?).3:50 PM. Another view of Cirrocumulus. Though these clouds are still composed of liquid droplets, the 5 PM TUS sounding suggests they were at about -30 C in temperature. It happens.4:00 PM. An incredibly complex array of Cirrocumulus overhead. Due to perspective, its about the only view that you can really see how complex the patterns are.4:20 PM. Some iridescence for you.6:00 PM. At Oracle, AZ.6:22 PM. Finally, from the “Not-taken-while-driving-since-that-would-be-crazy-though-it-looks-like-it-was” collection, this oddity. Looks like an high temperature aircraft contrail (aka, “APIP”) in the lower center. And the trail seems to shoot up into the cloud Altocumulus cloud layer (or down out of it). Have never seen that kind of aircraft track before since it looks so steep! “High temperature” here means that it formed at temperatures above about -35 C.
Whew, the end.
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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.
1While several inches of model2 rain has occurred in Catalina and in the nearby mountains this month, most of which cloud-maven person has festooned his blog with model panels of, there really hasn’t been any ACTUAL rain.
But having said that, there is even MORE model rain ahead, some beginning tomorrow in these parts. Tomorrow’s rain comes from a sub-tropical minor wave ejecting from the sub-tropics. You know, as a CMJ, a wave from that zone means a ton of high and middle clouds, i.e., likely DENSE Altostratus with virga, something that was seen yesterday off to the SW of us. This time, though, some rain should fall from these thick clouds, though almost certainly will be in the trace to a tenth of an inch range between tomorrow and Monday morning.
Model rain from 11 PM AST global data then falls in Catalina on:
February 24th
March 1st
March 7-9th
with the model total rain in these periods likely surpassing an inch or more! What a model rain winter season this has been! Astounding. The model washes have been running full since late December, too!
BTW, that last model rain period is really a great one, a major rain for ALL of Arizona!
Some recent clouds I have known and a couple of wildflowers
7:36 AM, Thursday, Feb 19: Iridescence in Cirrocumulus.7:52 AM, Thursday, Feb. 19: Iridescence in Cirrocumulus with a tad of Kelvin-Helholtz waves (center, right), ones that look like breaking ocean waves. Kind of cool looking.9:29 AM, Thursday, Feb. 19: Altocumulus perlucidus exhibiting crossing patterns, rows perpendicular to each other. Makes you think about football and people running out for passes.9:42 AM, Thursday Feb 19: An extremely delicate crossing pattern in Cirrocumulus, center. You’ll have to drill in good to see it, but its worth it.10:39 AM, Thrusday, Feb 19: Pretty (mostly) Cirrus spissatus, a thick version in which shading can be observed.6:13 PM, Thursday, Feb 19: No idea what that stick contrail is. Looks like a flight pattern to induce weightlessness. Climb rapidly, round off the top, and then go down. You can be weightless for maybe 10-30 seconds. Been there, done that in a C-130 Hercules, last FACE flight of 1973, Bill Woodley lead cloud seeding scientist. But, you pay a price, get smashed on the floor as the aircraft comes out of the dive. You cannot get up!Let’s zoom in and see if we can learn more about what happened here. I think a jet pilot was having fun. Nope.6:54 AM, yesterday. Altostratus virga provides a spectacular, if brief sunrise over the Catalinas.6:15 PM last evening.From a dog walk this VERY morning, a desert primrose.And a desert onion bloom.
The End. Hope you enjoy the copious model rains ahead!
First you had the rarely seen “Aircraft Produced Ice Particles” (APIPs, or “High Temperature Aircraft Contrails” (HTACs) in supercooled Altocumulus in the afternoon. Contrails were being produced in clouds that were “only” -20 C to -30 C (-4 to -22 F) and aircraft contrails were thought to be impossible at those temperatures, but rather, only at much lower ones, below -40 C (-40 F) or so.
Then, just after sunset, the heavy layer of Altocumulus produced a sun pillar! I was out in Saddlebrooke having dinner with friends after sunset, so had to leave dinner for about ten minutes, but I was so excited for you that I had to see it for myself, too. Since it would have been obscenely rude to tell my dinner friends the true reason why I left, when I got back after many minutes I told them I had to pee, and that seemed to go over pretty well I thought1.
Below, a coupla shots of that sun pillar I got while “peeing” on your behalf:
5:33 PM Gently falling pristine2 hexagonal plate ice crystals, falling face down from mostly supercooled Altocumulus clouds, produce a sun pillar. This site says that sun pillars are typically seen with Cirrostratus clouds and I have not photographed ONE due to Cirrostratus clouds myself, but rather ones like this falling from……yes, that’s right, Altocumulus clouds having just a bit of ice in them. How funny is that?
5:33 PM. Closer look as it fades. Note the small liquid water mammatus bubbles upper right. Mammatus in liquid clouds is also pretty rare since they are downward moving puffs of air and droplets evaporate much faster than do ice crystals. Mammatus is nearly always restricted to ice clouds for this reason. Was also wondering if my oversize salad and hamburger had been served yet.
Let us look at our sounding and see if we can see how cold those Altocumulus clouds were:
Tucson sounding launched from our U of AZ around 3:30 PM yesterday. The arrows denote the likely heights and temperatures of the Altocumulus we saw, somewhere around -20 C (-4 F) or -30 C (-22 F) for both. Hard to tell which layer was the one the aircraft were flying in, but the colder the supercooled cloud the denser the ice trail. So…..since they were dense yesterday, CM is going with the one at -30 C. Yes, that’s right, liquid droplet clouds can exist at -30 C, full reasons not known, but indicates a lack of ice-forming particles up there. But, it can also happen at the ground, too, in fogs.
Here are some of the magical, rare scenes from aircraft making ice canals in those very cold supercooled Altocumulus clouds:
2:25 PM. Ice canal over Boot Barn down there on Oracle somewhere.2:29 PM. Contrail castellanus (that row above the pole)? Had never seen anything quite like this before. Going crazy over sky phenomena now. Word Press, as here, is corrupting some of these images; can’t fix it so far.2:50 PM.
3:51 PM. Just above corrupted part of this file–I’ve given up trying to fix it in WP, is an aircraft streaking through this Cirrocumulus/Altocumulus deck, and an ice trail will form. How can you tell that that aircraft is IN the cloud and not above it? Look for different movement between the contrail and the cloud. If they are moving together, its usually the case that the aircraft was in the cloud. The aircraft is in the cloud at left.3:51 PM Close up. Very excited that a trail would develop. You almost never see the aircraft leaving the trail like this; you see the trail after the aircraft is long gone.
Skipping to the chase, as hard as that is to do, this trail really lit up as it got to the 22 degree point from the sun, where mock suns and such happen, producing a rainbow of colors due to iridescence, a rainbow producing by very tiny ice crystals in this case, of the order of a few microns in size.
3:55 PM. Started to glow a little orange here.
3:55 PM. Close up of the feature event. Was turning brighter colors as the seconds went byStill 3:55 PM. Going from orange to blueish.STLL 3:55 PM. Color fades into white as this icy contrail in the Altocumulus raced eastward. More WP corruption here, too. Think I’ll quit! Just too much time to do this to have this kind of crap happen! Sorry, having little baby tantrum now.
Guess about today’s clouds
Maybe a few Cirrus, patch or two of Cirrocumulus, and likely lenticular clouds, particularly off to the north.
The End
The big storm everyone’s talking about?
Oh, yeah, baby, its still comin’, begins on Wednesday, New Year’s Eve in the afternoon, continues for about 24 h off and on.
Bracketing possible precip totals: still 0.25 inches on the bottom (10% chance of less), 1.50 inches on the top (10% chance of more). Average of those two often brings the best estimate, which would be about 0.87 inches, somewhere in there. You know, when you deal with wobbly cut off lows, you just can’t be real confident in how much rain they’ll bring. However, it looks like the north part of the State will get the brunt in snow, which will be great for the water situation.
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1It would be fun to hear what your excuses were as a “CMJ”–Cloud Maven Junior, if you were in a similar predicament last evening and HAD to see that rare sun pillar, rather than meet new people at dinner who wouldn’t be able to understand you anyway because you are compulsed like that; leave a great dinner to go outside in cold air to take cloud photos.
Well, nobody really understands a CM.
I remember in grammar school and Junior High in Reseda, CA, when kids teased me on clear days , saying, “Hey, Artie! Is it gonna rain today?” Then they would laugh at me for being a CM before I even answered the question, knowing all the while what the answer was going to be. Still, out of civility, I would answer them: “No, we’re having Santa Ana conditions now and it can’t rain for at least five days”, but they would still be laughing in the midst of my explanation about why it wasn’t going to rain. Kind of a sad scene when you think about it, that is, how mean kids can be to kids who are different. Later, when I became a pretty good athlete, they liked me, which shows how important athletics is over knowing stuff, and helping you “fit in.”
2 “Pristine” means that can’t be gunked up by having collected cloud droplets on their faces because then the optics, like sun pillars, mock suns, that kind of thing can’t happen if the crystals are messed up with droplets on them or a lot of extra hexagonal arms sticking out of them, as in bullet rosette ice crystals.
One of the best, really, never mind all that wind yesterday. No rain, of course, in our future, not even fantasy rain these days.
See usual rehash of yesterday’s clouds, the 60s, in case you forgot, below:
8:49 AM. This Altocumulus perlucidus cloud behaved like a lenticular, holding in place for at least 2 h, but did not have the classic pancake or sliver look of lenticularis clouds. Air likely too unstable (temperature dropped with height rapidly) and allowed tiny cumuliform elements to form. Only on the very right edge where it first formed, did this cloud appear “lenticular” in any way with its smoothness
10:15 AM. More classic looking, sliver Altocumulus lenticularis beyond the Catalinas. Cloud forms on the right edge, dissipates on the left as the air rises and falls slightly.
11:58 AM. Cirrocumulus (delicate granulation) on the fringes of Altocumulus (larger elements on the right). 12:01 PM. These clouds change by the second as the degree of moisture in the air jetting along up there ebbs and wanes. Look how much larger that fine granulation on the left got in just a couple of minutes. 2:09 PM. One of the many examples of iridescence seen yesterday in those Cirrocumulus clouds, or on the very thin upwind edge of Altocumulus lenticularis clouds. Its due to the formation of extremely tiny droplets, a few microns in diameter, that cause diffraction in the sun’s rays (see link for a more complete explanation and nice examples). Do you remember that white light has the wavelengths of all the colors in it? Here you can see some of them, and photograph them by performing a replication of the Black Power salute of Tommy Smith and John Carlos from my alma mater, San Jose State, one that beat the Wyoming Cowboys recently in fubball. I added a link in case you forgot and wanted to get worked up again. Yes I was at SJS when that happened down Mexico way, minding my own business doing weather forecasts with a political slant (left, of course, because that’s what made you popular during the rad lib days) for the college paper. Suddenly, I feel like going to San Francisco, putting some flowers in my hair.…
2:19 PM. Cirrocumulus and Ac lenticularis in the same layer. Recall Cc can’t have shading, not that it matters that much.
4:39 PM. This dramatic scene amid the dust and wind. This would be an Altocumulus lenticularis, one that devolves into Altocumulus perlucidus (honeycomb pattern seen downwind from the distant leading edge).
It was zero visibility in Parhrump, Nevada, yesterday afternoon with wind gusts to 85 mph, as the cold front was about to crash on by. I guess we were lucky to only have 40-50 mph puffs of wind here in Catalinaland overnight, and not so much dust (yet). A sharp, but dry cold front is bearing down on us, but the low center that was so intense yesterday over Nevada, then moved across Utah, has faded trying to move through the Rockies. This means that the winds will be much less than yesterday.
Does that mean no dust around Catalina today? Nope. Those strong winds in Nevada and western Arizona yesterday raised a lot of fine (as in tiny) dust particles that are likely to be suspended for a day or two, and so we’ll likely see dusty skies today, without so much wind anyway.
We had some nice Altocumulus/Cirrocumulus lenticular clouds in the afternoon yesterday. I wonder if you saw them? They weren’t around for long. Here’s what they looked like.
The last shot is of a cigar-shaped flying saucer with multicolored lights, OR, a Cirrocumulus lenticularis showing some slight iridescence (which are those rainbow colors near the edges of the cloud due to diffraction). You have to look very hard to detect coloration in this cloud shot, but its there. Diffraction is the bending of sun’s white light as it passes around the tiny (micron-sized) drops in the cloud and that leads to a separation of the white light into its components of reddish, greenish, blueish colors.
Take yer choice on what was photographed, but it is true that clouds such as lenticulars have been reported as flying saucers that “hover” then disappear. This cloud was completely gone in one to two minutes after this photo AND was stationary, as lenticulars are in the face of strong winds aloft and at the ground, which also influences the observer’s reports of unexplained “hovering.” This little cloud had been much larger ten minutes before reaching this size.
You can probably understand why such reporting might happen when you look at how smooth this little lenticular was. And sometimes, when nearer the sun’s position, the colors caused by diffraction are quite vivid.
Wildfire smoke
Also, in the late afternoon some smoke from the Nogales wildfire headed our way. It gave a great example of what young smoke looks like, that is, smoke recently emitted from a fire nearby. Its always got lots of gradations of the smoke in it because it hasn’t been around long enough for turbulence to mix out the smoke into a homogenous layer. This happens when smoke has been around for days and days and has traveled thousands of miles, and so its one way of telling that a smoke layer has come from a long distance.
Sometimes high, smooth, long-range transport smoke layers can be mistaken for Cirrostratus, hold yer hat, “nebulosus”, a completely smooth ice cloud without much internal detail. Below, the smoke from the Nogales area as it headed northward toward Catalina.
Rain possible?
It seems as dry as this system is, about all we can hope for is a trace.
It does appear that there will be enough moisture by tonight and for a couple of days as this cold air over us hangs around that we will see high-based (that is, probably based at or above the top of Mt. Lemmon) Cumulus and Stratocumulus clouds, and with the low temperatures aloft, ice should be able to form in them–which as you know, means virga, snow falling out and melting on the way down.
However, it would appear that only sprinkles are possible at ground level here in Catalina.
What to do?
You won’t want to miss entering the fact that a sprinkle occurred in your weather journal, one that might only last a minute or two, and so its best if you keep, say, your car parked outside where a layer of dust can accumulate, and then, when the rain drops fall, they will leave impressions in the dust.
The full moon of last evening, FYI.
Factoid: it is thought that the moon was originally part of the earth, the result of a gigantic (!!!) impact that sent part of the earth out into space which then became our moon. This theory would explain the synchronization of the moon’s face with the earth, that is, having the same face toward the earth. Hmmm. Hope we don’t have another one of those soon. Two moons would be mind boggling.
Like an errant bowling ball (you remember bowling, don’t you?), the models are now pretty much in agreement that instead a “strike”, or at least a “spare”, or even a few “pins” being knocked down here in Catalina, by our approaching, spinning “ball” of low pressure, it is now foreseen to end up as a “gutter ball”, bypassing the “lane” entirely and heading off to to coast of southern Mexico, the way the Canadian forecast model had been saying all along. The US model had rain here for days on end, and it passed much closer to us. But not now. Below is the latest awful depiction from IPS Meteostar if you haven’t seen it yourself, one valid for Wednesday evening at 11 PM AST:
This is one of the worst forecast maps I have ever seen. You can see where the low ends up, over Cabo!
I felt I had to prepare you mentally since no models I can find out there have any rain here with that system now. And there is no rain seen in the next 15 days in the US WRF-GFS model, either! So La Nina!
This is an odd configuration down there off Mexico, too. This is normally the dry season in central and southern Mexico, so some Mazatlanians and Puerto Vallartans are going to get quite the winter surprise down there in a couple of days. It would be fun to go down there and see the surprise on the faces of vacationers and locals when this thing hits, to see, really how weather impacts people. As a meteorologist, I feel much more important when important weather strikes. People want to talk to you then and ask things; “How long is this going to last?” “Have you ever seen this happen before?” You’re really kind of the focal point of everyone’s life then. You’ve probably noticed how excited TEEVEE weather presenters get when weather is the lead in the news, with that kind of haughty smile, or pretending to be sad, because a hurricane just hit, or six feet of snow fell somewhere.
But when important weather hits, they become the stars of the news programs, and maybe “stars” for a couple of days! Yes, that’s what we weathermen and women like, odd weather, NOT normal weather where we have to think of “happy talk” and jokes and things to say to our fellow anchors instead of talking about something important. I have to say I am a part of that weather culture, too. But with no storm at hand, I will not be so important to my friends today1.
Yesterday’s iridescent clouds, in case you missed them
Iridescent clouds are ones with especially tiny droplets that produce rainbow colors because the light is diffracted around the drops, and in doing so the white light from the sun is broken up into into its various wavelengths and colors that go with them (reddish, longer wavelengths, bluish, shorter wavelengths. For a nice explanation and spectacular examples, go here. Yesterday’s iridescence appeared yesterday in newly formed Cirrocumulus clouds.
Revealing personal note——————————————————————————————————————————————————————————————————————————————————————-1This whole “storm-now-missing-us” thing and loss of importance reminds, too, of John Denver, and when he died in that plane crash. In those days before that happened, people used to say I looked like John Denver or thought I was John Denver, strangers even, and maybe I cultivated that look to make myself seem more important than I really was. It was great having a stranger want to talk to me, often a woman as it turned out. But then when John Denver died, I was sad, not for John or anything like that, though I did like some of his songs, but because I knew I pretty soon people would not ask me if I was John Denver and want my autograph, as happened in a Durango, Colorado, supermarket where I lived. I was pretty bummed out back then, really, and that’s the way I feel about this “gutter ball” thing today. Below, me as “John Denver.” BTW, mom liked to be “Marilyn Monroe” so that she would seem more important, so this is kind of a family culture we Rangnos have to boost our self-esteems. It really helps when you’re only a weatherman or other ordinary person to be somebody famous! There was a guy just last night at the Fox Theatre here in Tucson pretending to be former Beatle, John Lennon! I’ll bet he felt great because it was just like John Lennon actually being there!
Yes, we had some yesterday evening in those Altocumulus lenticularis clouds or just “clouds” for most of you. This delicate “rainbow” coloring in last evening’s clouds is due to the diffraction of light around really small cloud droplets, ones that have just formed, a few microns to 1o microns or so in diameter. Because the droplets have to be “really small” to produce this effect, iridescence is almost always located at the upwind edge of clouds that thicken downwind, as these do. It was more colorful than I could photograph, but here are a couple of shots of that phenomenon we call cloud iridescence, or irisation:
By the way, the winds at cloud level here (around 2o -22 kft above the ground and at -30 C or so) were just about 100 mph (85 knots) at this time as that huge trough over southern California edges closer to us. Unfortunately, it is “ejected” to the northeast out of southern Cal this morning and that means that this whole upper level system will be moving faster and faster as it moves toward Arizona and then into the Plains States. That means that the band of rain generated with this system will be moving through at a faster pace and for that reason won’t produce as much rain as it might have if the system was not speeding up. Still, looks like we should get, here in Catalinaland, around a quarter to half an inch. Very exciting, since it will do what vegetation we have some good.
Free range grazing land now down to about just dirt, as little of the spring grasses have poked up before being ravaged by hungry cattle and native wildlife. Kinda depressing after last spring’s bountiful display of grasses and wildflowers. I have contrasting photos below as well. You won’t like what you see in this comparison because it brings our droughty winter into sharp focus. What is nice about our desert is that the mesquite and acacia bushes/ trees don’t seem to care how dry it is and are still are intensely green this time of the year, some consolation for the lack of green elsewhere.
You also may be struck by how tall I am, perhaps I played basketball in college you wonder. In the first photo illustrating the dry conditions, I am apparently several feet taller than my wife, Judy, who walks ahead of me with Zuma, one of our dogs. I guess I could have been on stilts, but I am actually on our horse, Jake, and am not that tall FYI.
