I hope you had a chance to venture out late yesterday morning and see some of the most spectacular Cirrus (uncinus) displays with HUGE streamers that you will ever see.
The early Cirrus cloud were nothing very special, not showing clues about what was to happen a few hours later:
7:46 AM. A complex sky with Altocumulus on the right and various species of Cirrus such as Cirrus spissatus, center.
But by mid-morning, racing in from the west, these:
10:58 AM. From the Rillito Bridge at Swan, this amazing scene with Cirrus uncinus and those gigantically long tails of ice!11:08 AM11:08 AM. Mimics trees in a way, both reaching upward.11:14 AM.11:12 AM. From the Rillito Bridge at Swan again. Kind of running around like a chicken with its hat off! The heads of the Ci unc are overhead.11:11 AM.11:14 AM. One final shot.
—————
There was an interesting contrail distraction later that day. Are these “castellanus” crenelations, or is it perspective? Those knobs are usually pointed downward due to the action of the wingtip vortices that take them downward behind the plane. Maybe they’re just sloped down at us, not puffed up.
1:10 PM.
—————-
Late in the day some Altocumulus advanced from the west, providing a nice sunset, but a layer once again impacted by aircraft holes. Can you find them (with their trails of ice slanting downward?)
5:38 PM.
The End
Well, there is still a chance of some rain late in the month, late or after the TG holiday weekend….. FIngers crossed. Poor wildflower seeds.
Yesterday, after an ordinary beginning,, finished in a spectacular, if likely artificial way. Let us work our way through yesterday’s cloudulations:
7:39 AM. I thought this was a cute display by this little cloud, making its own little shadow rays as the sun made its way up from behind the Catlinas.7:40 AM. But what kind of cloud is it? It, to these eyes, is all ice, but LOOKS like an Altocumulus cloud. But those clouds are all or mostly comprised of liquid drops. And you can see that this little guy is well BELOW a higher layer of ice cloud, we might call CIrrostratus, or a thin Altostratus. Oh, well, let’s move on to something explicable….
7:41 AM. Hmmmm. Quite a linear virga feature over there. There are THREE cloud layers evident here, a thin Altocumulus layer, that dark cloud on the left, and patch of what I could call, Altostratus extending from the left corner to the right corner, and a thin layer of CIrrostratus on top.7:41 AM. Let’s go zooming and check it out…. Though we don’t know for SURE, anytime you see this kind of linear virga anomaly, you should be smelling aircraft exhaust. Now, when you think about our fabulous sunset last evening and what that looked like, take a closer look at this photo.
Later that morning…..
10:53 AM. It was nice to see low clouds topping Sam Ridge at dawn yesterday, the lower boundary layer air (where convection takes place) moist for a change. Later they devolved into small Cumulus (humilis and fractus).3:29 PM. A day with mostly ice clouds on top of Catalina, but here, off in the distance below the Cirrostratus, is an invading layer of Altostratus and Altocumulus that will set the stage for sunset glory later. You may be able to detect a faint halo, upper center. By the way, Cirrostratus typically deepens downward to morph into Altostratus, usually an ice cloud, too, but is deep enough to produce gray shading, and when its really thick or has embedded droplet clouds, hides the sun.4:02 PM. Yep, moving right in. This is a very complex scene. There’s aCirrostratus ice layer. upper right quadrant , on top of everything. Below that, what appears here as a distinctly lower separate layer, a mix of Altocumulus (those dark cloudlets composed all or mostly of liquid droplets) and Altostratus (mostly or all ice, the smudgy more diffuse dark areas) . We can never forget that Altocumulus can morph into Altostratus, which would then be called, “Altostratus altocumulotransmutatus.” Tell that to your friends! (Well, maybe not.)4:15 PM. Caught this bumpy aircraft contrail at CIrrus levels. Look how how the exhaust and water vapor that formed this, though output from an aircraft in a steady state, how the wing tip vorices (apparently) get entertwined at regular intervals with more exhaust and water vapor in those blobs.
But let’s go zooming up to flight level and take a closer look for a second:
A “mammatus” (or as the ladies like to call it. a testicularis contrail (the resemblances are pretty good). Almost certainly this is due to combining wing tip vortices. Many aircraft now have devices to defeat wing tip vortices, phenomenon that reduce flight efficiency. In both cases above, the ice particles have not grown enough to produce fallstreaks. These images tell us that SOME aircraft that produce ice in supercooled Altocumulus clouds, as we in Catalina have seen lately, are likely to have bunches of ice trails rather than a continuum if produced in a uniform cloud, anyway.
Now, where was I? Got mammatus on my mind again. I love mammatus so much… Oh, yeah, that sunset yesterday…..
5:13 PM. Ran out to check sunset status, and saw this feature advancing rapidly toward Catalina.5:18 PM. Zoomed view; getting close to passing overhead. You might be able to notice that these pretty regularly spaced trails are BELOW the Altocumulus clouds, and there’s a clearing that’s been produced. All evidence of an artificial production of these trails. But belng below the Altocu, you might also have started to wonder whether the setting sun would light them up….
And the sun did its job….producing one of the greatest sunset scenes we’ve seen in a long time, even if phony (haha):
5:23 PM. Not zoomed, still a few minutes away to overhead passage. Very exciting to think this was going to pass overhead!5:23 PM. Zoomed view. Again the pretty regular spacing is circumstantial evidence that nature didn’t do it.5:25 PM. Thank you sun! Looks pretty round again, which is good.5:27 PM. Oh, so pretty.5:27 PM. Zooming again. Wow.5:28 PM. Another view of the same thing.5:28 PM. Our trails compared to the rest of the Altocumulus deck. Not much going on elsewhere in the way of natural virga.5:29 PM. Taking WAY too many photos of the same thing. Out of control… Here I demonstrate that with another photo of the same thing.
5:30 PM. After the trail hoopla, it was time to concentrate on the fabulous sunset taking place to the southwest of Catalina.5:30 PM. Zooming in on interesting features; long trails, one with a clearing above it. Was it another aircraft-induced trail of ice and clearing above it? Probably. The trails to the left aren’t as obviously produced by an aircraft, but I do think so anyway in this burst of objectivity. Recall that I have been trained as a “scientist” and don’t care if I am wrong, but only about truth, as best as I can make it out.
Finally, let look at the TUS sounding for last evening, see how cold those Ac cloud were with the ice trail in them:
Results of the Tucson rawinsonde balloon launch yesterday at about 3:30 PM. Goes up at about 1,000 feet a minute, so takes about 100 minutes to get to 100, 000 feet. They pop somewhere around that height or a little above. THought you like to know that. They have a little parachute to that when they come down, they don’t bonk you too hard. Once in awhile people find them in remote areas downwind. You can send them back in to the NWS, too!
The astounding thing here, something that goes against everything I believe about clouds, is that it is indicated that the Altocumulus, lacking much natural ice, was at -30° C! Yikes! No wonder aircraft were producing ice trails and stuff yesterday afternoon.
You have to conclude there were almost no natural “ice nuclei” up there at, oh about 24,000 feet above sea level. This is not the first time for such an occurrence of liquid clouds sans much ice at low temperatures1, but they are rare IME. This would never occur in a boundary layer cloud, that is, one where material from the earth’s surface is getting into the clouds, like the omnipresent dust, or biogenic ice nuclei.
The weather ahead
Some “fantasy” storms with rain in them for Catalina, are now seen on the model predictions beyond a week. Spaghetti is favoring this new development now. So, something to keep an eye on.
The view from here? Precip here is “in the bag” because going on subjective feelings, I really want to see a good rain here!
The End
——————————
1The famous John Hallett said he saw an Altocumulus lenticularis sans ice at -35°C in a conference preprint! Rangno and Hobbs (1986) claimed to have detected droplets in Altocumulus like clouds at the top of a storm on the Washington coast at -44°C. Their claim, first published in a conference preprint, was later rejected by the J. Atmos. Sci.
Not as good as a rain day with lightning, but yesterday did have its moments in the sky, enough to make the astrologers on Mt. Lemmon jealous with displays of parhelia (“sun dogs”, or “mock suns”), faint haloes, a rare parhelic circle, something you don’t see but once every year or two, and fallstreifen (fall streaks) from Cirrus uncinus clouds going in almost opposite directions, an extremely rare sight.
The rare “parhelic circle” is a local brightening often extending out from a parhelia (sun dog) at a sharp angle, which I just learned about here1. Usually you don’t see a whole circle, just part of one.
These optic displays are caused by ice crystals, of course, ones not too complex, but rather simple ones like prisms, short solid columns, bullets, and hexagonal plates. Some examples of these can be seen here.
The bottom of yesterday’s moist layer was just above 30,000 feet at a temperature of -35° C and extended all the way up to about 40,000 feet above sea level where the temperature were around -65° C.
The balloon sounding launched around 3:30 PM AST yesterday from the Banner University of Arizona.
Some photos documenting the excitement of yesterday
5:30 PM. Cirrus uncinus crystals heading in two very different directions. Wow. Notice the fibers from the contrail that are starting to fall out are going in the “correct” direction, back toward that west or southwest.3:04 PM. Parhelic circle erupts in mostly Cirrus uncinus clouds.3:06 PM. The astounding sight continues, but fades away just after this.3:33 PM. Local brightening at the position of a sun dog suggests these are tiny ice crystals or possibly even droplets that have just formed, the sizes too small to allow refraction into color normally seen in sun dogs.3:32 PM. A zoomed view of that little bright spot. Sure looks like it may have been droplets. Droplet clouds have been reliably reported to temperatures as low as -44° C. Of course, wouldn’t stay liquid long! I thought this was a pretty exciting shot! Hope you got it, too.
3:42 PM. Amid all the optical excitement was this ghost-like halo. Can you make out the faint circle around the sun? In ascents through thick ice clouds having complicated ice crystals like bullet rosettes down below the tops, as you climb to the top of such clouds, amazing haloes can be seen where the crystals are newly formed and quite simple in structure, allowing the refraction required for a halo. So, this halo was likely at the top of these thicker Cirrus and Altostratus (dense portions) clouds, though no one would penalize you if you just said they were all Cirrus clouds.
3:59 PM. Another spectacular bright spot at the sun dog location (which is also at the 22° halo location, faintly evident here).3:59 PM. Zoomed view of this sun dog/parhelia. Lots of fine structure evident, which is not usually the case with parhelia.4:25 PM. Another finely structured parhelia/sun dog suggesting the ice crystals were newly formed. Fine structure like this can’t last long with the usual turbulence, and so that’s a sure sign this feature has just formed. I don’t recall seeing so many atypical sun dogs in one day!5:09 PM. The normal, amorphous sun dog. No really fine detail can be seen here.
Below, examples of cold Cirrocumulus, ones that quickly transition to Cirrus clouds.
5:19 PM. This group of CIrrocumulus clouds appeared very quickly almost overhead. The tiniest elements are those that have just formed. These are composed of ice crystals in extremely high concentrations, perhaps 10,000 per lilter. Once that ice has formed, its gradually spreads out, much like a puff of smoke would, thinning, some crystals growing large enough to start fall steaks.5:19 PM. Some elements are still forming, but the spreading of the older ones is well underway, producing a “blurred” look as the elements merge and thin out.5:28 PM. Off to the southwest of Catalina, a promising intrusion of lower moisture indicated by these approaching Altocumulus clouds. Will there be enough today for a sprinkle somewhere? Not looking so good now, clouds did not lower much overnight. Well, maybe if it doesn’t sprinkle, maybe we’ll get to see some nice virga and dream about rain…
If you thought those high clouds were moving faster than usual, you were right. The winds were about 120 mph at that level, about 28,000 feet above sea level, and just over 150 mph a few thousand feet above that level.
You may have noticed two things, if you are good, that there were repeated formations of delicate Cirrocumulus clouds, likely starting as liquid drops, but quickly transitioned into Cirrus. Sometimes, it was just flocculent Cirrus the whole way to us from the west.
The second thing that you may have noticed was that there was always an upwind clearing zone that remained stationary until late afternoon when it finally passed overhead. Yesterday’s high clouds formed at that back edge.
How can you tell that the upwind edge of that sheet of clouds was initially composed of liquid droplets, but then froze naturally within a minute or three as it jetted downstream?
Perform an experiment to demonstrate the two phases.
In this case we will have an ice producing aircraft fly through both regions, the droplet region, and also the region where no droplets exist because they have frozen and are growing larger and larger as ice crystals.
What will be the predictable result of two ice-producing aircraft flying through these two different phases?
In the liquid cloud region, an ice canal will develop as the appearance of ice in a droplet cloud results in the evaporation of liquid droplets, the molecules of vapor from the evaporating droplets provide “food” for fattening ice crystals, where “deposition” takes place. Under a microscope you would see the crystals getting larger, growing extensions; you would not be able to see the molecules producing that, of course.
The result of our experiment, something you likely will never see again in my lifetime:
3:36 PM. Letting the font size demonstrate the excitement I was feeling, that excitement filling the whole sky! Maybe the temperature in this inadvertent experiment would be stupefyingly low, like -40 C (-40 F), in which case I might get a publication of my photos. Another great aspect was that this canal was streaking toward me (us)! It just could not have been a better situation. And I would add, in retirement mind you, to my CV and I don’t even have a grant! It was going to be a great day!3:40 PM. See photo.3:47 PM. Normal contrail in ice cloud continues to evolve as ice canal gets closer.3:49 PM. The aircraft contrail that was emitted in all ice clouds. Still are all ice, though you may say they look awfully tufted like they could have droplets. They’re glaciated, all ice. Go with me on this. I’m the cloud maven.Helping hand points out ice canal. By this time the clouds around that ice canal had also transitioned to ice.Also at 3:47 PM, a zoomed view of ice canal. You can see the little ice fibers in that clearing, the ones than caused the evaporation of the droplets around the initial ice formation. Likely at this point that the surrounding cloud, though rather “flocculent” looking was also now ice.3:52 PM. As usually happens with aircraft produced ice, the tiny, overabundant crystals are pristine, perfectly shaped hexagonal solid columns or hexagonal plates, and that perfect shape usually results in strong optical phenomena at the point where a sun dog or 22 degree halo is observed due to the refraction of sunlight in those crystals. You only had seconds to see this, those clouds were moving SO FAST, and I missed the brightest point.
3:53 PM. One final look at our receding ice canal, gradually being filled in by natural Cirrus.
Was holding breath, thinking about that CV enhancement, waiting for the TUS sounding, which was already in the air when these last few photos were taken, and, more importantly, it was going up near where the clouds were forming, so the moist level intercepted and its temperature would be pretty accurate for this shots. Now, if its -40 C, oh man, we got a pub! -36 C, maybe. Temperature greater than about -35 C? No pub, well, except here, which is something. That’s because liquid drops at temperatures between -30 and -35 C have been reported by remote sensing and aircraft repeatedly. Nature abhors forming an ice crystal in clouds without going through the liquid phase first.
Within a couple of hours the TUS sounding was in, and here it is:
The TUS balloon sounding launched about 3:30 PM, rise rate about 1,000 feet a minute. Shows Cirrocu layer was “only” about -33 C (-27 F). Boohoo.
I wasn’t going to get a journal pub. I thought about that guy that thought he was going to win the Nobel Prize…..and I know now how he felt.
Now about those pretty patterns, by Simon and Garfunkel. Enjoy.
Jet core at 18,000 feet now passing overhead and DRIZZLE or very light rain from warm processes now (4:15 AM) evident on the Catalina Mountains. The passage of that jet core at that level (500 millibars) seems to be an almost black-white measurable rain or no rain discriminator in the Southwest US, so as that happens right now, chances of some measurable rain are good. Still not expected to be more than 0.25 inches, but will now at least be 0.01!
The low clouds are pretty shallow now, and, if they rain, shallow clouds with tops warmer than -5 C (23 F) have to be pretty clean for that to happen. Clean clouds is got bigger droplets, ones that reach the Hocking-Jonas threshold of between 30-40 microns in size and can collide and stick together forming still much larger drops that collect more and more tiny cloud droplets, kind of a chain reaction, as Nobel Laureate in chemistry Irving Langmuir described it back in 1948 after he got interested in clouds and rainmaking.
However, the “collision with coalescence process will be short-lived as cloud tops go up to well below freezing level this morning, and real rain falls (as is happening now (7:18 AM) down in TUS and to our NW.
Measurable rain should be just on the doorstep, and it will have to develop in upwind clouds as they approach us and the air begins to rise as it goes uphill from the lower deserts and encounters the Catalinas’ there isn’t much in the way of radar echoes upwind of us now.
The development of rain in clouds as they approach us in marginal rain situations like this one is not terribly unusual. Sometimes, as a friend pointed out, new echoes in deepening clouds can appear over and over again near where I-10 runs to the SW and W of us in a purely orographic situation.
This is what CMP is hoping for, and the result of that might be a tenth of an inch or more.
Well, fountains spray water, and storms spray water (and snow) on the ground, so quite an unexpected confluence in descriptions, comparing fountains and storms.
That’s right, three storms are shown in the model run from last night. They been kind of coming and going, the model generally clueless about what’s really going to happen here, especially with California gully washing rains from the lower latitudes, that then affect Arizona.
However, they’re BACK, those gully washing rains in southern Cal, beginning around the 6-7th of Jan. They used to be exceptionally ferocious and floody in the WRF-GFS and came in on Rose Bowl day, that day when we were all dreaming of Ducks floating around in Pasadena. California Dreamin’, as it turned out. The floods now showing up would only be ordinary ones, at least to start.
But, “hey.” enough said about California! What about us?
A little snow overnight or the following morning after the day after Christmas. That would be the 26th. Precip amounts have to be light, since the trajectory of this cold storm is completely over land, but then that helps keep it cold, though I am not in favor of cold.
Amounts, again; Since its marginal to begin with; 0 to 0.25 inches max in melted snow water, if it snows.
Then what?
Next, on New Year’s Eve, the model, as rendered by IPS MeteoStar, erupted with this Arizona “fountain” number 2:
Valid at 5 AM AST. Jet core is already south of us, brown and reddish area, so it on the verge of raining here at that time.
But, as you know, when a low is predicted to be by itself, as in this case, the prediction is “iffy”. But, lows like this one, should it verify, bring the longest duration of rains and snows to Arizona, i. e,. are fabulous drought-denting storms because they move very slowly when out of the main flow. In fact this one would take more than 24 h to go by! You’d be looking at somewhere in the neighborhood of a half inch to an inch of precip here in the Catalina area.
Below, “fountain” number 3 “in preparation” as we say about our manuscripts, sometimes ones that never materialize in a journal, as it is with some of these storms the model predicts.
Truly, I say to you1, this is what dreams are made of for a southern California precipophile; get the sandbags out! Years of below normal rain, rectified! Drought busted! Let’s see what drought bustin’, mutton bustin’, cow-punchin’, drought stompin’, calf ropin’, hornswaglin’, storm herdin’ map really looks like:
Valid at 5 PM AST, January 5th. Drought bustin’ portent all over this map!
Don’t even need to show what happens after this, “Juicy” out there mixes it up with some Arctic air and is slammed into southern Cal with Hawaiian-like dewpoints and rain. Just like calf ropin’. That cold air and upper jet extruding offshore will “rope” Juicy in. Lotta “warm rain” involved, too, that type of rain that forms without the need for ice.
While Juicy loses some water and some punch after southern Cal, it would still be a big rain producer in Arizona, particularly the northern half. We would likely be just inside the edge of the southern edge of this. Still, we have to be glad for the State as a whole as our water situation would vastly improve with these storms, especially storm fountains 2 and 3.
Valid at 5 PM AST, Jan 5th. Looks pretty damn good for breakthrough flow to “the other side”, from the central Pacific to the West Coast and Great Southwest, wouldn’t you say? Note the bunching of red lines from the east Pac into Arizony. Chances better than average that we’ll see this break on through to the other side, Doors, 1967.
Standing by for snow and rain…. Sincerely, standing by for rain, C-M.
Yesterday’s day in contrails
Pretty upset yesterday as contrail after contrail formed and floated over Catalina. I don’t mind contrails when I’m flying somewhere, never even think of them, but when they foul the natural sky, I am livid.
Fortunately, the air got drier up there and contrails were rare after 10 AM. I can hardly stand to post this, but will for the sake of documentation so that you may be outraged as well. NIMB!
9:21 AM AST. Barrage of contrails fouls natural sky. Hope you’re mad now.
We hope this barrage was mainly due to those exceptional jet streams winds rushing down from Canada into the interior of the Southwest toward New Mexico causing airway contrails to shift over us.
Exceptional?
Some winds between 30,000 and 35,000 feet were clocked at over 200 mph! Great if you’re going from Seattle to Albuquerqueque, but not so great if you’re going the other way.
The End.
—————–
1I had a sudden urge to say, “hypocrites!” just then for some reason. Crazy.
2″Spaghetti tasters”…. Made me wonder what happened to that great underground/alternative music band, The Oil Tasters… Remember their big hit, “Slit Chapped Lips“? Great example of what the 80s underground music scene was all about, that raw, exploration of different sounds, the overall contempt for “pop” music, the kind that makes a lot of money, like that produced by the Four Aces, etc.
(Can’t find that song about chapped lips on YouTube, its that good!) ((Later, found it!!))
((Can’t believe that I have touched the entire extrema of music in one blog, from the Four Aces on the left, to the Oil Tasters on the right, and everything in between; i.e., The Doors, 1967!)) (((Just shows you how deep your music knowledge can go; can it get any broader3?)))
3I remind the reader that if humor like this is not your cup of tea, nor the personality I effect here is also not, that my offer to stop blogging for a million dollars is still on the table.
Due to some kind of server meltdown, the NOAA spaghetti plots, better, “Lorenz plots” in honor of “Dr. Chaos”, Edward N. Lorenz, the ones my fans1 like so much, have not been available.
But they’re back today!
But what are they telling us? Gander this for Christmas Day:
Valid at 5 PM AST Christmas Day, December 25th. I’ve annotated it especially for you. The view is one where your looking down at where Santa lives from a big tower. Not all annotations are accurate.
Don’t need to tell you that the weather looks like there’s a good chance of cold and threatening weather for Christmas Day. Big trough implanting itself in the West around then. Maybe those easterners who hogged all the cold air last winter will share some of it this winter. The warmth we had last winter made it bad for horsey with all the fly larvae that survived.
Kind of bored now with the rain immeidately ahead, but only because everybody else is talking about it, too. Its no fun when you don’t have a scoop and you’re just saying things that other people are already saying. Even my brother in North Carolina, who knows nothing about weather, told ME that it was going to rain here on Thursday! How lame is that? Of course, it is true that you won’t here anywhere else that the chance of measurable rain is more than 100% this week in Catalina ; at least I still have that. Tell your friends.
When does it fall? Sometime, maybe multiple times, between Tuesday afternoon and Friday morning. Hahaha, sort of.
Looks like the first trough and weather system will go over on Tuesday through Wednesday, chances of rain then, and yet another colder one on Wednesday night into Thursday. So, 100% chance of measurable rain falling sometime between Tuesday afternoon and Friday morning, probably in several periods of rain. Look for a frosty Lemmon Friday morning.
Predicted amounts from this keyboard? Think the bottom of this several day period of individual rain events will be only a quarter of an inch. Top, could be an inch, if everything falls into place. Canadian mod from 5 PM AST global data yesterday, for now has dried up one of the storms, that on Thursday, the day the USA! model thinks is our best chance for good rains based on the virtually same global data! Of note, the USA model based on 11 PM AST data, has begun to lessen our Thursday storm that bit.
This is the reason that the certainty of measurable rain here in Catalina is spread over such a several day period.
Your cloud day yesterday
Just various forms of Cirrus, most seemingly from old contrails that produced exceptional parhelias (sun dogs, mock suns).
Very contrail-ee sunset, too, as contrail lines advanced from the west. They were likely more than an hour old when they passed over Catalina yesterday.
10:56 AM. Glistening rocks after the rain. Very nice. Cu fractus at moutain tops.
2:36 PM. Nice example of the rare seen Cirrostratus fibratus (has lines in it). Hope you logged it.
3:42 PM. Looks like old contrails to this old eye, resembling CIrrus radiatus. The “radiating” aspect may be due to perspective.
3:50 PM. Parhelia lights up in CIrrus. These, due to the high speed of Cirrus movement, only last seconds in thin streamers like these. To get really spectacular optics the crystals up there have to be especially simple, like plates and stubby columns, maybe prisms as well. When aircraft create contrails, there is an excess of ice crystals, far more than occur in natural Cirrus as a rule, and due to that high concentration, can’t grow much and usually stay as simple crystals, not develop complicated forms like bullet rosettes, crystals with stems sticking out every which way.5:23 PM. Contrail-ee sunset. Pretty, but awful at the same time, since it shows how the natural sky can be impacted by us in our modern lives. You wonder how much of us the earth can take?
The End
—————–
1Why just recently C-M had a comment from a fan in Lebanon3, that country near Israel, not the one in Ohio2! Said it was warm there now, but normally it rains for days at time in the winter, and gets real cold. You see, the eastern Mediterranean is, climatologically speaking, a trough bowl. Troughs just hang out there a lot, creating something called the “Cypress Low.” Though it only rains in the cool season, October through May, as in Israel, places in Lebanon get 25 -40 inches of rain during that time, and its exciting rain because it almost all falls from Cumulonimbus clouds, many with lightning! C-M is getting pretty excited, since he’s on record as wanting to go Lebanon to study the clouds there! See Lingua Franca article from 1997! He loves those Mediterranean wintertime Cu. Hell, you probably threw it out, so here it is: Lingua Franca _1997. See last sentence. last page. Thanks.
2Speaking of Ohio, who can forget that great 1980s rant against urban sprawl in Ohio by Chrissie Hinds and the Pretenders! Will it happen to Catalina after the road project? An insurance agent told me that Catalina was to be absorbed by Oro Valley after it was completed. Oro Valley says they know nothing about that.
Valid for Friday afternoon, 5 PM AST, November 22nd. Arrow points to beau coup eastern AZ precip amounts.
The loop above, generated by last evening’s global obs by the Enviro Can “GEM” model might be the best a numerical model can put out for Arizona. It might even be the best model day of my life ever here (which hasn’t been that long, but still…).
Why?
1. Trough races into the precip “Red Zone”, located immediately SW of AZ. Rain moves in on Friday into Catalina and environs.
2. Trough forms circular, spinning low aloft there, that wanders slightly in place. Cloud and precip rush into Arizona, and it just doesn’t quit as wave after wave of clouds and rain move up from Mexico, the Gulf of Cal-Sea of Cortez, and the Pacific off Baja while the low center dawdles.
3. Low crosses into AZ and departs AZ late Sunday after showery day.
In sum, showery rainy conditions beginning on Friday, continuing into Sunday.
Amounts should be several inches in the mountains of AZ. Here, sans the great U of AZ calcs for the whole storm period, will go with the same “seat-of-pants” estimates of the botttom and top amounts made a couple of days ago: at least 0.4 inches (even if things don’t work out so great; low doesn’t dawdle so long). But as much as 1.50 inches on the high end here in Catalina if it DOES dawdle as this model run from last night shows and we get nailed by recurring rain bands. Best estimate, “therefore” he sez, is the average of the two, or about an inch.
It would seem some thunder now and then would also be in the mix, and BTW, we remind our reader that snow and rain mixed together is NOT SLEET, dammitall! SLEET is frozen raindrops, ones that have frozen on the way down and usually requires two to three thousand feet of below-freezing air temperatures before that happens. Also, they BOUNCE when they hit, are usually clear, and often have spikes where the water was trying to get out since they mostly freeze from the outside inward, and because water expands when it freezes, a spike or ejection of ice splinters results as freezing takes place. Kind of neat really. But its NOT rain and snow mixed together! Sorry, getting into some “sleet rage” here; need to work on it; get it under control. I just don’t want my reader to sound ignorant when rain and snow are mixed together, but rather, “precipitationally erudite.”
Yesterday’s clouds5:20 PM. Jet’s ‘n’ Cirrus. The very short contrails, formed by moisture and carbonaceous crap, oops, black stuff, in the exhaust, are short here because the jets are flying ABOVE the Cirrus.
5:42 PM. OK sunset.
The moon’s been HUGE lately, enough where you can see quite a bit of detail.
Here’s a nice little example of how the weather computing models start to go awry fast when a little flummoxed when little DELIBERATE errors are input into them as they start their northern hemisphere data crunch (below, from the global data ingested at 5 PM AST yesterday). Us folks here in Arizona and those in the Southwest US comprise one of two “centers” of the greatest uncertainty in all of the Northern Hemisphere, as shown below in the red and blue lines (selected height contours at 500 mb).
Model outputs and what they are predicting will go to HELL faster due to our “zone of uncertainty”. Chaos in action. Wiggle something here, and it falls apart over there and all over. This example is the contour forecasts for 5 PM tomorrow.
Valid for 5 PM AST Monday, February 4th.
Does this epicenter of uncertainty hereabouts mean we have a chance to get some real rain in the next 36 h?
No, but its great that you know about this uncertaity and how it plays out in the NOAA “ensembles of spaghetti”; useless-in-some-ways-knowledge, absorbed just for the sake of knowledge.
The uncertainty illustrated above is associated with a upper level wiggle in the winds and exactly how that will play out as that wiggle moves toward us from the NW today. Its a little baby trough in the upper air flow that the model is uncertain about but it is too weak to have much affect on the big cloud mass that will be drifting over us today, that cloud mass originally from a location about halfway between the Galapagos and Hawaiian Islands. These are real tropical clouds over us today, and they’ll be piled in layers (Altostratus, Altocumulus, Cirrus, Cirrostratus) over us to more than 350,000 feet!
Range of amounts here in Catalina: ZERO on the bottom to 0.10 inches, tops.
Below is an example (full set here) of what the Beowulf Cluster from the U of AZ sees in the moisture overhead at 3 PM local time (in other words, during the 84th hour of the Superbowl pre-game show). I realize that many of you will not be able to go outside and look at the sky at any time today due to this historical sports emergency, and so I will tell you something now about what you likely would have seen had you gone outside, perhaps even missing an equally historic commercial break of some kind:
Forecast sounding for 3 PM AST today, an hour before Superbowl kick-off.
What does this mean?
Weird clouds, most likely. Scoop clouds, concave (downward) looking cloud bottoms. Some areas of the sky might look like ocean waves upside down, “undulatus” clouds (we had a short-lived Ac undulatus yesterday to the NW of Catalina). Clouds with waves on the bottom. The bases of our tropical clouds are likely going to be in a “stable layer”, one where the temperature remains the same as you go up. It would be located just above the top of Ms. Mt. Lemon. Along with that stable layer, and is always a part of them, is wind shear; the wind turning in direction and speed as you go upward from just below this stable layer to above it.
Stable layers and wind shear produce waves, not ones always seen since the air is often too dry for clouds, but in this case, they should be visible. Could make for some interesting cloud shots this afternoon and evening. Here’s a risky example of what I think is likely, though with too much virga falling from above, they won’t happen, hence, the risk in a cloud detailed forecast:
An educated guess about how this afternoon’s cloud bases will look. There’s likely to be much more cloud cover, however, than is shown here.
Yesterday’s clouds
Lots of contrails overhead yesterday, an unusual number. Really, we are SO LUCKY not to have many days like this, kind of a sky pollution, though at present, an unavoidable one. Just be glad we don’t live right under a main, well-traveled airway (though, with predictions of a doubling of air traffic by 2020, we are likely doomed to more days like yesterday when Cirriform clouds are present).
Our deep blue sky, loaded with interesting Cirrus clouds yesterday, and generally low in contrail impact, makes southeast Arizona a haven for Cirrus cloud watchers. Though no one site is completely immune from them, a sky like this, so free of contrails, is impossible on most of the Atlantic Seaboard due to air traffic. It was just so pretty here yesterday with so few contrails! Here are a few shots:
10:01 AM. Mostly Cirrus fibratus advance toward Catalina.11:30 AM. Tenuous strands of CIrrus fibratus, ones underneath higher, scattered Cirrus clouds. Long strands like these require hours to form, and moist air for a great depth below the much higher, spawning flecks, now long gone.2:05 PM. The upstream tail where the much of the Cirrus clouds form approaches. The lack of long strands, and little specs of cloud tell you that these Cirrus clouds are quite young.5:19 PM. Patchy young Cirrus clouds with an older contrail at right. This photo shows how contrails eventually evolve to resemble natural Cirrus clouds.
The weather ahead: cold front’s a coming
Its been well predicted for 1-2 weeks that a cold front would pass through our area on Dec 9th-10th. At times the models had substantial rain here, but it’ll be a dry blast from the north Sunday night. What makes us here in Catalina a little different in experiencing this frontal passage is that the high pressure behind the front pushes air along the Catalina mountains from the north here, and we often get quite a windy episode, 15-30 mph likely Sunday night. But, because we have no official weather reporting stations, and the Catalina Mountains block that north wind from Tucson so that they don’t get it, so us here in Catalina are about the only folks that know its quite windy, with a chill in the air.
This cold front is part of a large scale pattern change in the jet stream that is taking place, one that will vastly increase our chances of rain in the weeks ahead as storms barge into the Pacfic Coast farther south than they have and head this way. No longer will we be in a stagnant condition where day after day the weather is almost exactly the same; not much wind, temperatures above normal. Instead there will be occasional windy episodes as storms get close, temperatures closer to normal, and we hope, one that gets far enough south for a good rain.
Some rain is showing up now overnight on the 13th-14th. In our rain frequency chart, the peak rain days in December were the 11th-13th, deemed a statistical fluke from this keyboard in the 35 year record.
But, here’s a rain threat materializing in the very window. Hmmmm. Further, if you look at the spaghetti plot for this time period, a trough is guaranteed in this region on the 13th-14th, though getting circumscribed by the jet stream that is, its south of us as the trough goes by is what’s marginal with this trough situation, a requirement for almost all winter rain here.
Usually when you get carried away and expect something unusual to happen, it doesn’t, like that girl I thought liked me but didn’t (there have been a number of those…) Yesterday, carried-away Mr. Cloud Maven person mentioned the possibility of tubes in Cal. Here’s the report in the Big Valley near Merced, CA, from yesterday. Big hail, too. I am pumped! Spiking fubball now!
0535 PM FUNNEL CLOUD ATWATER 37.35N 120.60W
04/12/2012 MERCED CA PUBLIC
3 DIFFERENT FUNNEL CLOUDS IN THE ATWATER AREA
0605 PM HAIL ATWATER 37.35N 120.60W
04/12/2012 M1.75 INCH MERCED CA AMATEUR RADIO
Official name of tube-producing clouds? Oh, something like, “Cumulonimbus capillatus incus (has an anvil) tuba.”
Actually, its not terribly unusual to have tubes in Cal when the air is extremely cold up top over Cal in April and May, and that’s what we have now. Take a look at this nice, compact map from San Francisco State Former US Hippiedom Capital Weather Department for last evening at 5 PM AST. At San Francisco, its -29 C at 500 mb, very unusual for mid-April. (Actually, they got some real nice maps there.) Combine that with the strong sun on land surfaces, and voila, Cumulonimbus galore!
Also, if you look carefully, you will see that where there is no data, over the Pacific Ocean, the 500 millibar pressure contours are nice and smooth . But notice how “nervous” they get once crossing the coastline where there is data. I think really it has something to do with the interpolation scheme that try to place the contours exactly at the right spot between the real data; that algorithm may be a little primitive. Kind of funny in a way.
That cold core of air is heading for Arizona, and no doubt some April low temperature records will be set, such as lowest maximum, and likely a few minimum temperatures before this passes on into the Plains, with no doubt true severe weather there the result of that. And we, too, will have some Cumulonimbus clouds, lightning here and there around the State.
Below the SFO State map is the forecast from IPS Meteostar showing where this mass of cold air will be later Saturday at 5 PM AST, northern AZ. U of WA WRF-GFS mod thinks rain will be occurring here just about ALL DAY on Saturday after beginning around dawn! That would be a heckuva cold day, winter-like, with temps in the 40s-50s here at 3,000 feet and we’d have those pretty white Catalina Mountains afterwards. Sure seems like 0.20 inches is in the bag for the bottom of this rain event, with maybe 0.50 inches being at the top here in Catalina.
Yesterday’s line of enhanced virga in As deck at sunset
Now here’s an odd feature. Looked at first that it might have been due to an aircraft passage in that streak of Altostratus, but then I rejected that thought, as I can do. I came to believe somewhat confidently, odd as it is, that it was natural. Natural linear features in clouds are fairly common. Here it is, in case you missed it:
