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.
Friends, arriving this afternoon from Seattle for a sunny and warm couple of vacation days, will find that Catalina weather today is exactly like the weather they left in Seattle; poor Tommy and Patty.
Clouds will fill in as the day goes on, becoming pretty cloudy at times, especially in the afternoon hours. They will starting to ice up, too, and you know what that means; they’ll produce virga and light showers in the area, with breezes and a high of only in the low 50s.
Be sure to record the first sighting of ice in clouds today. Will be a nice test for you, and a great ob in your cloud diary.
Still expecting a pretty major storm next week.
Got 0.12 inches in the gauge last evening.
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In the meantime, meet members of the former Cloud and Aerosol Research Group at the University of Washington, Professor Peter V. Hobbs, director.
Tom, who arrives today from Seattle, was our group’s software engineer at the University of Washington. He was kind of recluse we learned after he was hired. Liked to have a lot of high vegetation around his desk in our lab where me and a grad student worked. However, unlike a prior software engineer, who was also brilliant like Tom, Tom really never fell asleep at his desk that we know of.
“Jungle Tom”, our brilliant software engineer in the Cloud and Aerosol Research Group at the University of Washington. I hope you can find him.
Our first software engineer was Doug, shown meditating below.He was great! Worked long hours that often took their toll in the daytime.
But, not to demean “Doug” whatsoever, who truly WAS brilliant, and his software helped enormously to grease the wheel of our group’s aircraft data analyses, and who also made a lot of money when he joined the then fledgeling Microsoft in the early 1980s, took his job especially seriously, He liked to let people know how seriously, and exactly how much he loved working with computers. And he dressed to show it.
Software engineer, “Doug” arriving at work one day.
Cloud and Aerosol Researcher, “Stan”, monitoring cloud particle data on a flight over the Washington coastal waters.
It was a fact, that as I got embedded into perhaps the best Atmospheric Science Department in the world, I also learned that science draws “unusual”, maybe even quirky folk, and “meditating” while on the job, perhaps “awaking” with new, substantive realizations of relationships, or ways of presenting data, was pretty common, not just with Doug:
Graduate student, Stan, monitoring flight data in a cold front over the Washington coastal waters.Cloud and Aerosol Research Group flight engineer, “Jack, ” responsible for seeing that the instruments were functioning properly..
But there were other quirky characteristics that turned up, like “Germophobe John”, shown below, who actually shared my lab room for many years:
Germosphobe “John” at work. After awhile, of course, you don’t notice these quirks, although the rustling of plastic all the time was annoying when he working.Aerosol expert “Dean” we’ll call him, who worked down the hall was an asymmetric dresser, and took great pride in that. It was also a way that he got people to talk to him when they came over to point out that his clothes weren’t buttoned correctly. Dean was a leader in the sartorial rebellion of the day.
Then there was that one guy who worked as part of the flight crew who specialized in looking like John Denver, and liked to come in to work in the morning and report that someone on the bus he rode thought he was John Denver. Seemed to get a lot of satisfaction out of that, which in retrospect is kind of sad when you think about it.
One of the CARG team members who took pride in being mistaken for John Denver. We in our Group remember how sad he was when John Denver died in a home-built plane crash.
Me? I was pretty normal, really not too much affected by the various quirky people around me. From those halcyon days, a selfie:
The author, Arthur, in the early 1980s. I suppose the double pair of glasses was somewhat unusual, but other than that, I was fine. I suppose I was mad about some stuff in the domain of cloud seeding, maybe a little of that showing here.
There was some thought, however, that any quirkiness that was exhibited in our personnel might have been due to the various cancer-causing chemicals we worked with, one of which was Formvar, used to capture images of ice crystals that would hit the liquid Formvar on movie film rotating in the arm of a probe that stuck out of a pod, or a glass slide that stuck out a hole on a stick in the plane. In both cases, the crystal would hit the liquid Formvar, which would dry VERY fast, and then the impression of the crystal would be left in the plastic Formvar.
Below, “Diana”, and “Brad”, a brilliant grad student, at least before he started working with Formvar, examine a jar of the smelly stuff.
“Diana” and “Brad” , flight crew members, examine a jars of Formvar and maybe trichloroethylene used in conjunction with collecting ice crystal images while in flight.
Yesterday’s clouds
7:37 AM. Hope you saw this anomaly. The linearity suggests this line of mammatus was ice generated by an aircraft.
9:23 AM. Altostratus with puffs of new cloud forming on the upstream edge. What would those separate tufts be called. I don’t know for sure, maybe, Cirrus floccus or castellanus. Sure looks like Cirrus uncinus before it turns gray toward the east.
11:06 AM. Moisture below the level of the earlier cloud begins to arrive, showing up first as a lenticular cloud in the lee of the Catalinas.
1:01 PM. Before long, clouds at different levels began to appear. Here, two layers of Altocumulus the main one above a lenticular one.
3:53 PM. This was about an hour before virga and falling snow began to obscure the tops of Samaniego Ridge and Mt. Ms. Lemmon. Here the streaks, crespuscular rays, are NOT caused by precip, but rather dust
Some additional scenes from a 4 h yesterday into the Sam Ridge foothills:
Stuck here, might reached a limit, can’t seem to add photos, and there are too many already.
When one first encounters this title with its unexpected play on words, we wonder what the author had in mind. Of course, most of us know that at Christmastime, we are often regaled by a Christmas tune called, “Frosty the Snowman1“. But here, we are surprised as we continue reading the title that instead of encountering the word, “snowman,” we encounter the word “Lemmon!” Hah!
What is meant here? What is author trying to tell us? Perhaps the word, “lemon”, has been misspelled. But if so, why would a “lemon” be frosty? Perhaps there was a cold spell in Florida and the author is harkening the reader to a long ago memory. Or, perhaps misspelling “lemon” was a literary device to emphasize that word in an eccentric way.
Yet, upon further investigation, we find that the issue is more complexed than first imagined. We find that there was an art teacher, nurse, and eventually, a self-educated botanist from New England, Sara Plummer Lemmon, who, with her husband and another worker, hiked to the top of the Catalina Mountains right here next to us, and while doing so, they logged the vegetation that was unique to the area. In their excitement when reaching the top, they named that highest peak after Mrs. Lemmon.
So, what does this piece of history add to our literary dilemma encapsulated in the title?
Perhaps Mrs. Lemmon did some work in the field of glaciology as well, hence, the word “frosty” as a possible hint of that work. Yet, upon investigation, we find no mention of work on ice crystals, hoar frost, nor glaciology not only in the work of Mrs. Lemmon, but neither in the work of any the team that mounted what is now known as Mt. Ms. Lemmon. We add that the note that the Lemmons, J. G. and Sara, were on their honeymoon at this time, historians tell us. Perhaps there is another avenue we can explore due to that latter element.
Could it be, too, that we are missing a characterization of Ms. Lemmon by our author? Perhaps she was shy, seen inadvertentlhy as “cold” by some, or was not particularly interested in the physical advances of her husband, J. G. The word “frosty” alert may be alerting us those possibilities.
Ultimately, we remain perplexed by this title; it forms an enigma that may never be confidently resolved.
But then good titles, and good books, are supposed to make us think, try to imagine what the author is telling us through his/her use of metaphor and other literary devices, and this title has done that.
We, of course, reject the most plausible, superficial explanation, that the author’s play on words was merely describing a local, snow and rimed-tree mountain named after Ms. Mt. Lemmon, as in the photo below. No, Occam’s Razor, the idea that the simplest explanation is usually the best one, will not do.
4:43 PM. Those trees are rimed, like the airframe of an aircraft that collects drops that freeze and cause icing. Here the wind blowing across the mountain top, and cloud droplets that were below freezing, hit the trees and froze over a period of many hours, creating this scene. Its not snow resting on the branches. That would’ve blowed off in the strong winds up there.
———End of Literary Criticism Parody Module———-
There was a rousing 0.24 inches of rain yesterday! Our storm total has topped out at 0.89 inches!
In other photos from yesterday:
9:42 AM. Altostratus translucidus again, with a few scattered Altocumulus cloud flakes, but this time with bulging Stratocumulus topping Samaniego Ridge, giving portent of a good Cumulus day if the As clouds will only depart and allow a LITTLE warmth. They did.
10:24 AM. Before long, cloud bases darkened here and there, indicating mounding tops above a general layer, and with the low freezing level of about 7,000 feet, the formation of ice and precip was not far behind.10:51 AM. Mountain obscuring showers were soon in progress due to both a little warming, but also because of a cloud energizing swirl in the upper atmosphere that passed over us at 1 PM AST. Did you notice that windshift aloft as that bend in the winds went by up there? You probably noticed that it was no dice, er, no ice, after 1 PM as the mash down of air that follows “troughs” did that very effectively after 1 PM.
10:52 AM. As the clouds (weak Cumulonimbus ones) broke, there was a fantastic rainbow for just a seconds to the north, landing on my neighbor’s house. It was even better before this, but was slow getting to the camera! Dang.
10:54 AM. “Pictures a poppin’ ” now as breaks in clouds allows those fabulous highlights of glinting rocks and scruffy Stratus fractus or Cumulus fractus clouds lining Sam Ridge, those highlight scenes that we love so much when the storm breaks. And these scenes change by the second, too!
11:00 AM.Also 11 AM. Out of control with camera now…..
11:12 AM. Meanwhile, back upwind… This line of modest Cumulonimbus clouds fronted by a weak shelf cloud roared in across Oro Valley to Catalina. What a great sight this was since now there was a chance of some more decent rains! Before long, the rains pounded down, puddles formed, and another 0.18 inches had been added to our already substantial total of 0.65 inches.
12:01 PM. But that wasn’t the end, was it? Before long, a heavy line of Cumulus and weak Cumulonimbus clouds formed again to the southwest and drenched Catalina with another round of rain, this time, only 0.06 inches. And with it came the End. This line of showers was spurred by that upper level wind shift that was going to occur over the next hour.
1:01 PM. Sometimes those clearing skies, the deep blue accentuating the smaller Cumulus clouds provide our most postcard scenes of the great life we have here in the desert.2:13 PM. While it was sad looking for ice in the afternoon clouds and finding none, the scenes themselves buoyed one. The instability was great enough that even brief pileus cap clouds were seen on top of our Cu.2:21 PM. Pileus cap cloud (right turret) tops honest-to-goodness December Cumulus congestus cloud. No ice nowhere.
2:28 PM. And if the sky and mountains splendor isn’t enough for you, then consider our blazing fall-winter vegetation as evidenced by a cottonwood tree in the Sutherland Wash,’ that yellow dot, lower center. We have it ALL now!2:48 PM. And, as the cloud tops are kept low, we get those fantastic, quilted, richly colored scenes on our Catalina Mountains we love so much. Here, looking toward Charouleau Gap and Samaniego Peak. I could show you so many more like this from just yesterday!
5:08 PM. Even our lowly regarded teddy bear chollas have luster on days like this, the weak winter sunlight being reflected off its razor-hook-like spines, ones that many of us know too well.
5:12 PM. And like so many of our days here in old Arizony, closed out with a great sunset.
Possibility raised in mods for giant southern Cal floods, maybe some flooding in AZ floods, too
Something in the spaghetti plots has been tantalizing as far as West Coast weather goes. They have been consistently showing a stream of flow from the tropics and sub-tropics, blasting into the West Coast. Recall that yesterday, that tropical flow was so strong and so far south, that at least one major gully washed was shown to pass across central and southern California on New Year’s Day, but weaken and shift to the north of southern AZ after that.
Well, my jaw dropped when this model run from yesterday at 11 AM AST came out, re-enforcing, even raising the bar on flooding, in central and southern California, and with those stronger storms, the possibility of flooding and major winter rains here in Arizona was raised. The severity of the pattern shown aloft is not one I have seen before, and for that reason alone, might be considered somewhat of an outlier prediction, one really not likely to occur.
Now, while there is some support in this model flooding “solution” in the spaghetti plots, the main reason I am going to present a series of what a disastrous Cal flood looks like is just FYI and how it develops. The closest analog to this situation was in January 1969 when a blocking high in the Gulf of Alaska (GOA), forced the major jet stream far south across the central and eastern Pacific on several occasions producing disastrous floods in southern California in particular, where one mountain station received more than 25 inches of rain in ONE DAY!
Also that blocking high in the GOA in Jan 1969 also forced unusually cold air into the Pac NW, where Seattle (SEA-TAC AP) accumulated 21 inches of snow over the month, still a record.
Here we go, in prog maps of our WRF-GFS rendered by IPS MeteoStar:
In the Beginning, the blocking high, shunting the jet stream to the south and to the north takes shape in the GOA. Note low far to the south between Hawaii and southern California. Get sand bags out now! This is for 11 PM AST, 28th of December.
24 h later:
Valid at 11 PM AST 29 December. Southern Cal flooding underway. Cold air pocket in Oregon has slipped southwestward helping to energize the lower band of jet stream winds by bringing cold air out over the ocean. The greater the temperature contrast between the north and the south, the greater the speed of the jet stream between the deep warm air to the south, and the deep cold air to the north. Note, too, high is getting farther out of the way in the Gulf of Alaska.
The situation continues to strengthen, and leads to this Coup de Gras, 11 PM AST January 1st. A system this strong barging into southern Cal is mind-boggling, and this panel is what brought this part of the blog, to show you what a devastating flood in that area would look like:
Valid at 11 PM, January 1st. In my opinion, I doubt the Rose Bowl game between the Oregon Ducks and Florida State would take place in Pasadena, CA, if this were to transpire.
Now for AZ. Here’s the prog for 12 h later, 11 AM AST January 2nd, Cactus Bowl Day in Tempe, AZ between the Washington Huskies and the Oklahoma A&M Aggies, to continue with sport’s notes here. Rain would be expected for that game should this pattern persist:
Valid at 11 AM AST, January 2nd. This is an unbelievably strong wave that has roared in from the lower latitudes of the Pacific. While it rushes through Arizona in a hurry, heavy rains, and some flooding are likely should things transpire like this.
Now for a gee-whiz, scary analog….one from WAY back in the winter of 1861-62 when the situation decribed above was likely very similar to what it was in that terrible flood; severe cold in progress in the Pac NW, as it would be in the upcoming situation; a tropical torrent raging in from the Pacific. This 1861-62 flood episode is still remembered. However, it went on for 30-40 days (!) with recurring episodes turning much of California’s central valley into a lake, Los Angeles area, too, where there was a report of 35 inches of rain in 30 days.
What’s ahead, really?
Well the models are going to fluctuate on the strength of this breakthrough flow “underneath” the blocking high in the Gulf of Alaska. But almost certainly one major rain event will break through as that this happens. Its kind of a fragile flow regime, so it usually doesn’t last long.
Whether it will be stupefyingly historic, or just another ordinary southern Cal gully washer, can’t be pinned down. But, if you lived down there, you’d want to be looking around and seeing what you could do to divert water, fix a roof, etc.
There would be strong, damaging winds with one of these “coming-in-underneath”, too, and, for surfers, giant waves!
Interesting times ahead! “Floodmagedon”, as we like to say these days?
No real weather here for awhile, except around Christmas when a mild cold snap, and a little chance of precip occurs as a cold front goes by.
The End, for awhile.
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1The most intellectually satisfying version of “Frosty the Snowman” was, of course, has been rendered by Bob Dylan.
The first of a couple of patches of rain over the next 36 h are passing through now, R at this second, 4:40:32 AM, and 0.09 inches of rain so far. Nice.
And with the last troughy coming across tomorrow during the day, with another chance of light rain then, too. Looks like we’ll easily go over 2 inches for the month of December (1.94 inches now), the first above normal in rainfall winter month since November a year ago.
Yesterday’s clouds and flowers
Not as widespread or dense as expected in the afternoon, but prettier, which helps counteract error. Let us begin our review of clouds with some paper flowers; there are still some blooms out there! Amazing.
8:25 AM. Seen on a dog walk under overcast Altostratus. Desert marigolds still going strong.8:38 AM. Classic Altostratus, some virga apparent below darkest part. Saguaro cactus is extruding slowly from the ground on the right. Need time lapse to really see it do anything.11:17 AM. Deeper clouds have moved away and now comes lower, shallow Altocumulus clouds some spewing virga. Photo annotated for Mark Albright, University of Washington research meteorologist who lives in Continental Ranch, and thus in the Tucson morning smog tide.
3:27 PM. One of the prettiest scenes of the afternoon, this array of Altocumulus.
3:27 PM also. Only the extra special Mark IV cloud maven personage would have caught this aircraft ice trail, originally within those lower Altocumulus clouds, much too warm for normal contrails. This is probably around 30 min old.
5:12 PM. Sunset in leading bank of clouds that led to the light rain this morning.
The weather way ahead
Threat of a larvae killing cold wave later this month fading; looks like that cold air will end up in the eastern US now, and no further precip after the series this week. Darn.
Front will roar across like a mouse, not a lion, as hoped for a few days ago. Not too many rain “calories” in it. Measurable rain will still occur, starting sometime between 9 AM and 10 AM AST–oops. raining now at 7:10 AM! Check out U of AZ model for rain timing. First drops fall here in that model output (from 11 PM AST last night), between 8 AM and 9 AM. The frontal band, such as it is, is almost here! However, the model rain tends to arrive a little fast here, though not always. FYI, be on guard.
C-M is holding firm with a minimum of 0.15 inches today, but previous foretold possible top of 0.80 inches a few days ago is out of the question. Will be happy with 0.25 inches at my house. Since I am also measuring the rain as well as forecasting it, I have a feeling things will turn out fine.
There will be a nice temperature drop, windshift, and simultaneous rise in pressure as the cold front goes by–it’ll be fun for you to watch the barometer today and see the minute the front goes by as higher pressure begins to squash down on you.
Rain might reach briefly moderate intensity (defined by official weatherfolk as 0.10 to 0.30 inches per hour). It would be great if it lasted an hour at that rate, but it likely won’t. Its moving pretty fast, and it doesn’t seem like more than 2 h of rain can occur today. Look for a nice clearing in the afternoon, and a COOL evening.
Drive south if you want to avoid rain today. Jet core (in the middle levels, 500 millibars, 18, 000 feet above sea level) is almost overhead, and just to south, and that core is almost a black-white discriminator of rain here in the cool season. So, we’re on the edge of the precip today. More to the north; less to the south.
Some clouds for you
1O:55 AM, December 11. Thought you should see this nice line of Ac castellanus and floccus underneath Cirrus spissatus.7:02 AM. Sunrise.12:32 PM. Wind picking up at the ground and aloft. Note tiny Ac lenticular with Cu fractus clouds.3:14 PM. The high cloud shield from the storm encroaches. Could call this either Cirrus spissatus or Altostratus translucidus.5:22 PM. Now we’re talkin’ Altostratus with underlit mammatus and fine virga. So pretty.5:29 PM. A late “bloom”, not really expected. Shows that there was a clear slot far beyond the horizon. Had to pull off by the Refuse Waste station on Oracle to get this. I hope you’re happy.
The weather ahead and WAY ahead
Speaking of bowls, and let’s face it, with only a 100 or so we could use a few more1; we here in all of Arizona are in the “Trough Bowl” now.
This means that troughs (storms and cold fronts) that barge into the West Coast will gravitate to Arizona instead of bypassing us and they will do that over and over again. Being in the Trough Bowl is great fun! Lots of weather excitement for weather-centric folk like yours truly. When you’re in the Trough Bowl, the weather is “unsettled”; is NEVER really nice (if you like sun and warmth) for very long because a new front/trough is barreling in at you.
So, while today might be a little disappointing, we will have many chances to get the “real thing”, i.e., a behemoth of a trough among the many that affect us in the weeks ahead.
In the longer view, a behemoth of a trough for the Great SW has just popped out of the models1 just last night in the 11 PM AST run! Gander this monster truck trough for AZ. Where’s that monster truck event announcer, we need him now!
Valid for 11 PM AST, Christmas Day! Wow. Can’t really take this at face value that far out, but if it did happen, likely would be snow in the Catalina area, and horsey would likely need a blanket after it went by. Will keep you informed periodically about this as the days go by.
OK, enough weather “calories” for you today. Hope you’re excited like me.
The End
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1Furthermore, why don’t we have bowls for women’s teams, what happened to Title IX there, maybe Beach or Sand Football? )
2As rendered by IPS MeteoStar, which is about to go from “free” to “fee” in January. Dang.
Flash: Plethora of storms lining up for Catalina during the rest of December. Spring wildflower seeds take note. Expecting to see a little snow here, too, in one of those–happens about once a year at our elevation (3,000 to 3500 feet), btw, so its not terribly unusual.)
The first one, on December 12th, is in the bag, the one we’ve talked about for a few months I think (that forecast based on spaghetti), except now it happens on the 13th. Droughty Cal will get slammed by this one, too.
Hope you’re happy now.
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Now, for the “main event,” a recapitulation yesterday’s clouds….
A Nice,cool and gray day it was, if you like sky-covering layers of Altostratus translucidus and opacus , interrupted in the mid-day hours by a lower layer of Altocumulus clouds.
Those Altocumulus clouds represented a “thin” corridor of clouds between deeper bands that went over us yesterday. Bands of thicker and thinner clouds are pretty normal as storms pass by us. First, this overview from satellite of our cloud sequence:
Visible satellite image for 1:15 PM yesterday when Altocumulus clouds comprised the main deck, rather than Altostratus. Too bad there was more humidity underneath this system,; coulda been a great rain. The arrow points to our location and the thinner cloud corridor that pass over at that time. Cloud banding like this always occurs with storms, providing lighter and heavier periods of rain over an hour or two.
From the beginning, these for your edification:
9:29 AM. Classic icy Altostratus translucidus. No droplet clouds evident. Hope you logged that remark. Estimated height above ground? 22, 000 feet at this time, somewhat lower than the balloon sounding indicated at 5 AM AST. Stuff lowers with time as storms approach.
11:29 AM. Big virga (falling snow) from Altostratus opacus (sun’s possible is not detectable at this time) rolls in from the horizon. Lots of weak radar echoes beginning to show up in our area. Some lower flakes of Altocumulus clouds can be seen at left center, and on the horizon, left center. Bases now around 18,000-20, 000 feet above the ground. Likely a few drops were reaching the ground where the virga hangs down another few thousand feet. Freezing level was around 11,000 feet above sea level.1:40 PM. Thin spot in satellite image, characterized by Altocumulus opacus clouds, was now passing over us between bands of heavy Altostratus with virga. As a CMJ, the appropriate thing to say to your neighbor would have been, “Wow (lot of excitement here), what happened to those deep clouds?! Cloud tops have really come down. Must be a thin spot. Hope that darkness on the horizon is another deep cloud band because then it might rain.” End of excitement. Cloud bases as you would guess, have continued to lower (but not nearly as much as the tops did). The Altocumulus bases here are estimated to be 12,000 feet above the ground. (By the end of the day, they were about 9, 000 feet above the ground, 12,000 feet above sea level).
3:05 PM. That last banded feature in the sat image, consisting of Altostratus opacus again, is starting to pass overhead. More weak radar echoes were present, some passing overhead, but, saw no evidence of a single drop on trace detector (car parked out in the open, moved for that purpose, since CM can’t be outside at all times.3:06 PM. Most of you will share my excitement here; surely a drop will be felt at any moment! As you know, in these situations, the rain hits the ground (largest drops first) long after the preciping part of the cloud has passed overhead. So, here we are looking downwind over the Charoulou Gap at a bunch of virga that passed over a few minutes ago, hoping for that drop that never came.5:01 PM. As the deep cloud tops moved away, and a large clearing approached from the west, the setting sun provided a golden view of Samaniego Ridge. The lower-topped Altocumulus clouds can be seen above Sam Ridge. Bases were now down to 9,000 feet above the ground. Tops were about 16, 000 ASL, about -13 C. Higher colder tops were still in the area producing virga.
5:03 PM. Even the teddy bear cholla, as horrible as it is, can be quite gorgeous in the evening light.5:19 PM. Later, sunset occurred, pretty much on time. It was OK. These, of course, are those Altocumulus clouds, sans virga; too warm in this case for ice production even with tops around -13 C, or about 9 F. Ice formation characteristics can vary from day to day, the reason is not always clear, but seems to be most closely related to the sizes of the cloud droplets. The bigger they are, the higher the temperature at which they freeze.
Below, from Intellicast, folks who hate Accuweather, where our radar network thought it rained a few drops on you (or probably just above you) yesterday:
Radar-derived precipitation for the 24 h ending at 5 AM AST this morning. Note dry slot over Catalina.
Here’s your cloud day for yesterday, a fairly complex day for your cloud diary entries:
7:27 AM. Looking SW along Equestrian Trail Road; Altocu with Cirrostratus above.7:45 AM. Altocumulus perlucidus over the Catalinas.12:38 PM. Stratocu begin to move in under the Altocumulus layer.2:47 PM. Altocumulus lenticularis began appearing, suggesting strengthening winds aloft. This was an odd location for such clouds, perhaps responding to uplift ahead of the Catalinas. Haven’t looked at Froude or Richardson numbers, though, to see if this is reasonable hand-waving.3:02 PM. Looking NNW at Stratocu (“the boring”; is State Cloud of Washington, and Oregon, for that matter) with a little Altocu on top.
4:33 PM. Stratocu. Kind of characterized the dull, dark, late afternoon and evening hours.
Intermittent R- to R– expected during the day today. Hoping for a quarter inch (forecast to friends early yesterday morning, 0.225 inches; will be ecstatic if more falls. Latest AZ mod has about that amount here, and over half an inch in the Catalinas. Usually, though, those amounts are on the high side. On the other hand, if the details about where the the rain band shown below are off a bit, we could do far better than the 0.10 to 0.25 inches predicted. Here’s the accumulated precip predicted for today from that model:
Accumulated rain until 10 PM AST tonight from the U of AZ model run at 11 PM AST, the latest. Much needed, nice heavy band of rain across AZ!
Next rain threat continues for the 12th, plus or minus a day.
Of course, only CLOUDS can rain, so the title is a little silly, but it sounded more dramatic like that. This is the first measurable rain, it fell between 9 and 10 PM here, in EIGHT weeks!
And you could sure smell that special fragrance from the ground and desert vegetation as soon as you stepped outside to do your exercises this morning!
Nice sunrise yesterday morning to start the day. In case you missed, of course, I am there for you.
BTW, in the captions below, I have included for you a discussion of climate issues in a kind of stream-of-consciousness format. OK, its a rant that came upon me out of the blue. CM sometimes gets mad and loses control for a few seconds; need to get some counseling maybe…
6:56 AM. Altocumulus perlucidus. Say no more. Might be a lenticular sort of on the right. Not the classic almond shape, but it did hang on for a long time in that spot. Say no more.
Kind of gray after that in Altostratus with an undercutting, lower layer of Altocumulus by mid-afternoon darkening the sky up some more. Some virga here and there with sprinkles-its-not-drizzle reaching the ground by late afternoon in the Catalina area. Here is your cloudscape for later in the day, very Seattle like during approaching storms that actually rain lightly on you for hours:
10:35 AM. Classic Altostratus translucidus, ice path in cloud all the way to the sun.10:39 AM, after walk down a slope to give YOU a view to the southwest, classic Altostratus as seen when not looking toward the sun. Hard to tell if its translucidus or opacus looking this way. By the way, even when you can see the sun, As clouds are thousands of feet thick, tops usually at Cirrus clouds levels.1:26 PM. Here come the lower, flocculent masses of Altocumulus clouds, ones composed of droplets.3:15 PM. It was all downhill for cloud bottoms after the Altocumulus moved in. Now, the bottoms are lumpy and much larger, casting them as Stratocumulus. There was some virga and very light rainshowers reaching the ground at this time, too. A few drops fell at 3:11 PM. Only the great cloud mavens of all time would have noticed. Lasted maybe one minute.3:15 PM again. Lot going on here, so I thought I would point out some things on a gray day, in particular for my fellow meteorologist Mark A at the U of WA who winters in the Tuscon smog plume. Mark is a super sleuth when it comes to snowpacks, but maybe doesn’t have so much moxie when it comes to smog. Mark, as you know may now, was fired as Assist State Climo for Washington when he demonstrated and kept complaining, along with two faculty members, that the claims of gigantic snowpack losses due to global warming (now repackaged as “climate change1“) in the Cascade Mountains were hugely exaggerated, likely the result of cherry picking a cold snowy beginning and ending with a run of El Nino winters, ones that lead to less snowpack in the Cascades of Washington and Oregon. Such cherry-picking led to a wonderful suggestion of huge declines that has led to a bounty of funding and continued employment, promotions, accolades, citations by Big Media, etc, because such claims, even if exaggerated and untrue, are what we want to hear! And, no one ever got a job for claiming they can’t find any sign of global warming, or only a little one, but rather are vilified for even suggesting exaggerations in the “global warming” domain. Mark, BTW, continuing his sleuthing has recently shown that similar claims for declines in snowpacks in Montana near Glacier National Park, have not been decreasing but rather increasing. He’ll get HELL for this one! So, more vilification is likely ahead for poor Mark, as well as more smog.
What’s ahead, besides the Big Pac 12 Fubball Game on Friday evening?
More clouds. Maybe a few more sprinkles especially tomorrow after dawn. See nice map below from the U of WA Dept of Atmospheric Meteorology (original colors on the map below by that big troublemaker, Mark Albright)
Valid for 8 AM AST, tomorrow morning, which is Thursday, in case you’ve lost count of the days of the week. The arrow denotes an upper level trough, or bend in the winds. Ahead of the bend (sometimes referred to as vorticity, or curling air, or red curly air) the air tends to rise producing cloud sheets, whereas behind red curly air, the air descends. See Seymour Hess, Introduction to Theoretical Meteorology, 1959, Florida State University Press. As you can see by the arrow, that slight bend in the winds is about to pass over your house in Catalina, and the U of Az model output from last evening sees a little rain here with that passage. Yay! Also note suggestion of bifurcated jet flow with a minor maximum in wind (slight bunching of contours) to the south of us, nearly always required for rain here in the cool season.
Beginning to wonder, with all the middle cloud thickness out there over and SW of Baja that’s headed this way if we won’t get sprinkles that produce a little measurable rain later today or overnight….
7 AM AST. Look at all those clouds over Baja and to the west of there.You can see this whole loop from the Washington Huskies here.
Models beginning to wetten things up here as well, like that Enviro Can model that sees our tropical surge high and middle clouds passing over us now, as deep enough for measurable rain later today and overnight. Huh. U of AZ mod, the best one for us, is still dry around here except on mountain tops. Our larger scale model, however, also has some very light rain in this area now, later today into tomorrow morning.
What’s intriguing is that a little jet core at 500 mb (up there at about the height of middle clouds) passes south of us as this happens, key for precip here1 in the cool season. The major jet stream is far to the north.
As you know, we have a bit of an El Niño going, both a “Classic Niño” as well as the “New Niño” going, and El Niños strengthen the southern portions of jet streams in the very way that we’re seeing in this situation.
They do that because its warmer than usual in the central and far eastern Pacific tropics due to heat in extra big Cumulus and Cumulonimbus clouds that pump away down there over that extra warm water, and that rising warmth produces a greater than usual difference in temperatures throughout the troposphere between the tropics and the mid-latitudes. Since jet streams are the products of temperature differences between warm and cold air around the globe, so unusually deep warmth in the tropical eastern Pacific gives a little strength tweak to jet streams coming into the coast2.
SInce there are two of these lower latitude “waves” traveling along in the southern branch of the jet stream, there are TWO chances for slight rains including that for later today. The next one barges in on the 6th of December. Will again be dense middle and high clouds with virga at its worst, like this one, though again a hundredth or two could happen.
Next real rain chance, and major front passage with air that’s too cold for us, will be on the 12th. Spaghetti folk, or “Spaghetti Busters”, those who can make sense of these balls of yarn, can EASILY see that trough on the 12th and a cold front with are “in the bag” even though that’s ten days away. Rain occurrence is more dubious, since the trough may land a bit too far east to produce rain, only a lowering of temperatures. Here is that plot from last evening. Enjoy.
Valid at 5 PM, December 12th. Pretty clear a nice trough will be in the area then.
Your yesterday’s clouds
11:44 AM. Up and down, up and down, those wavy air motions that produced this interesting line.3:37 PM. Classic Altostratus translucidus (sun’s position is visible).5:20 PM. Sunset Altostratus (ice clouds) and Altocumulus (droplet clouds).
BTW, for horsey people, the Cement Trough had water in it yesterday after being completely dry ten days ago:
11:44 AM. At the Cement Trough headed to South Gate.
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1See Rangno, 1973, unpublished manuscript and figures for the whole US using only the horizontal shear in jet stream at 500 mb as a definer of precip occurrences. Its really quite something, though, I guess you can’t see it.
2This was figured out by the Great Jacob Bjerknes of the Norwegian School of Meteorology while he was cruising into retirement (“Emeritus” status) at UCLA in the 1960s, though Chuck Pyke3,4, his grad student, did most of the work. Did a lotta work on the big “Classic” El Niño of 1957-58, which, per chance turned out to be an International Geophysical Year with a lot of extra observations! How lucky wazzat?
3Chuck, as you may recall was in the National Guard whilst at UCLA and was sent to Biloxi, MS, for two weeks of training and while there, was “gifted” with the passage of the eye of Hurricane Camille, one of the strongest of the century. Later the remnants of Camille, to go on and on, produced 31 inches of rain in 6 h in Virginia.
4Chuck P, who now lives in Arizona, also was very thorough in his evaluations of rainfall in his other studies concerning the seasonal timing of rainfall throughout the West. He once told me when I visited UCLA once to get Bjerknes autograph5 that he had gone to every rainfall measuring site in his study! Now some people go to every baseball park in America, but going every rain gauge site would be more interesting to cloud mavens. He further told me he found one that had not moved for 30 years, but the rainfall had been decreasing. When he went to that gauge, he found that it was being overgrown by a tree! This is why you have to check things.
5I failed. He was “Emeritus”; too good to be in his office that day. You see, your Catalina cloud maven was a strange person even then, wanting an autobgraph by Bjerknes rather than one by Mickey Mantle, though one by Mickey M would be worth a lot more today.
6:52 AM. Altocumulus cloudlets over and east of the Catalinas.6:52 AM. Sprinting to the other side of the house, this spectacular scene of virga falling from Altostratus. Breathtaking!6:53 AM. To the NW, the virga roiled downward into mammatus bulges under lit by the sun.6:54 AM. The color was fading just in a minute or two, but it was still a breathtaking panorama I thought you should see.
Some additional commentary about these scenes. One of the remarkable things about clouds, a real unknown, is how clouds such as Altocumulus (1st photo) can get so cold, colder than it was this mid-November in Wyoming, and can remain all or mostly water drops, which is what you are looking at in those cloudlets over and beyond the Catalinas. Pretty amazing. This phenomenon has been known about for decades, but not fully explained. We expect to see a lot of ice in clouds with tops colder than -30 C (-22 F) as you might imagine.
Here’s the sounding near the time of these photos, with writing on it:
———-Begin learning module———————————-
The Tucson balloon sounding, launched around 3:30 AM AST yesterday morning.
As a CMJ, you need to be armed with explanations if, on a morning walk, your neighbor, at first overwhelmed by the morning beauty, but then instead of being quiet, goes on to ask, “Hey, aren’t those clouds composed of droplets; they must be pretty low and warm?”
Since you’ve already seen the TUS sounding for the hours just before this, you know those cloud bottoms are real cold and high, -26 C, and 19,000 feet above you here in Catalina, and tops are really cold, about -32 C (-26 F), you cringe. What to say? How do you explain clouds that can sit there at -32 C and develop little or no ice, while knowing that Cumulus clouds, ones whose tops have never been colder than -7 C, can be completely composed of ice just after reaching up to that temperature?
—————-End of learning module, such as it was———————
Here’s another example from yesterday of extremely cold clouds with few ice crystals:
9:36 AM. Altocumulus perlucidus opacus (sun’s position is not detectable). The TUS sounding for the morning would not be valid at this time since the cloud bases were slowly lowering but they would still be about -20 C at this time, height about 17,000 feet above ground level. And, at this temperature, such clouds are ultraripe for ice production by aircraft that may flay threw them. See next photo for a POSSIBLE aircraft production of ice in these cold clouds.
10:43 AM. Of course, all of you were looking for some aircraft perturbation I’m sure, and this seemed “too linear, too uniform, the crystals too small (as deduced by the sloping lines of virga underneath this line for the ice to be natural. No other virga looked like this having straight fine lines underneath, the thing typical of contrails. However, its not the typical ice canal, either, with clearings beginning on the sides. In fact, the cloud seems thicker here where an aircraft may have traversed it, posing an explanatory challenge. Also counter to reason, why would an aircraft fly so far in what would have been light rime icing conditions in those Altocumulus clouds? Lots of questions, no really good answers.
11:07 AM. Linear feature passes over Catalinaland. Was hoping for a drop so I could claim it had rained in November, even if it had been a phony rain.
11:32 AM. Looks phony to me! Not a real cloud. I think we’re looking now at the tube of high concentrations tiny ice crystals that slowly settled out from that Altocumulus layer after an aircraft went through it–this tube to me appears to be BELOW the general layer, due to settling out after a few larger ice crystals fell out first. Am about 60 % sure that’s what happened and caused that linear feature. Getting pretty worked up about, too.
Well, Shakespeare said it: “Much ado about nothing,” so it must be important if he said it.
Had some really nice cloud scenes after the big clearing came through in mid-afternoon:
3:38 PM. Our typical spectacular lighting on the Catalinas scenes as storms move away.
4:49 PM. A dramatic finish to the day; light showers hit south and southwest of Tucson, but faded before arriving here.
There were some light showers that produced as much as 0.20 inches of rain in the south and east parts of Tucson late yesterday afternoon and evening. Nice for them.
The weather way ahead
Nothing in the way of rain in the immediate future. Have to wait until December for any real chances. See this bad boy for December 6-7th, this panel only 360 h from now1!
Valid at 11 PM AST December 6th. Note that the heaviest rain in Arizona is over Catalina! These are totals that accumulated in the 12 h prior to 11 PM AST. Hope I made you that bit happier showing you this. It’s a pretty cold system, too, might be a close call for snow here.
The End.
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1360 h in advance, even using our best model, is about in time like the distance to Betelgeuse in light years. Hence, caution when the writer says, “only.”
