Definitions – Page 30

A nice cloud yesterday, not a great cloud yesterday; dramatic day ahead

The clouds were somewhat of a disappointment yesterday, not the stupendous photogenic day CM was expecting.

Maybe CM is total fraud, gets Big Oil funding and should be investigated by Rep. Grijalva as other weather folk are, like the great Prof. and National Academy of Sciences Fellow, Dr. Judy Curry, a friend, and about whom I say on a link to her blog here, and from this blog’s very beginning, “The only link you will need.” I said that because Judy² is a top scientist, and is eminently fair in this polarized issue.

I am in real trouble! Will remove that link immediately¹ before our very own “climate thought enforcer”, Demo Rep. Grijalva, AZ, finds it using a spy bot! No telling how far down the influence chain it will go, maybe all the way down to here, where there is virtually no influence!

Back to clouds…….

Only late in the day did the delicate patterns expected to happen ALL DAY appear, again, with iridescence, always nice to see.

Here is your day for yesterday. Its a pretty interesting movie. Two thumbs up!

Oh, today’s weather?

The media, Bob, and our good NWS, of course, are all over the incoming rain in great detail. In fact, it will take you half a day to read all the warnings on this storm issued by our Tucson NWS.

So why duplicate existing information that might be only slightly different than the prevailing general consensus on the storm amounts, and then maybe be investigated for going against a consensus? No, not worth it. Best to be safe, not say things against The Machine. (OK, maybe overdoing it here.)

In the meantime, the upper low off southern Cal and Baja has fomented an extremely strong band of rain, now lying across SE Cal and the Colorado River Valley where dry locations like Blythe are getting more than an inch over the past 24 h. Same for northern Baja where some places are approaching 2-3 inches, great for them. You can see how the rain is piling up in those locations here. In sum, this is a fabulous storm for northern Mexico and the SW US, whether WE get our 0.915 inches, as foretold here, or not! Rejoice in the joy of others. Looking for an arcus cloud fronting the main rainband, too, that low hanging cloud in a line that tells you a windshift is coming. Still expecting, hoping, for thunder today to add to the wind and rain drama.

Also, the present cloud cover, as the trough ejects toward us, will deepen up and rain will form upwind and around here as that happens, so it won’t JUST be the eastward movement of the existing band. This means you might be surprised by rain if you’re outside hiking and think the band itself is hours away. Expecting rain to be in the area by mid-morning, certainly not later than noon, with the main blast (fronted by something akin to an arcus cloud) later in the day. OK, just checked the U of AZ mod run from 11 PM AST, and that is what it is saying as well! Wow.

Finally, if you care, yesterday’s clouds:

6:45 AM. Your sunrise color, thanks to a line of broken Cirrus spissatus. Jet stream Cirrus streak, as a matter of fact. — 6:45 AM. Your sunrise color, thanks to a line of broken Cirrus spissatus. Jet stream Cirrus streak, as a matter of fact, moving along at about 110 mph.

9:47 AM. Ruffle of Sc topped Mt. Lemmon, while strange clouds formed just upwind of them. These kinds of shapes suggest an inversion where the air resists further upward movement and a smoothing occurs at the top similar to a lenticular cloud. Photo taken at the Golder Ranch Dr. cattleguard. which really doesn’t work that well, as the neighbors below here will tell you.

The 5 AM, March 1st, balloon sounding for TUS.

9:53 AM. Looks like a crab with four hooks. How funny. — 9:53 AM. Looks like a crab with four pinchers. How funny.

12:23 PM. Shredding tops of small Cumulus like this indicate that the air is very dry just above their tops, and the shreds racing off to the right, indicate how fast the wind increased as you went upward.

2:58 PM. Something is changing here. Notice how the tops are bulging and not immediately being torn into shreds. The air was likely moistening above cloud tops, and the inversion holding the tops back, weakening as our storm gets a little closer.

4:19 PM. A line of heavy Cumulus had formed to the west, indicating more moistening and "de-stabilization" of the air. — 4:19 PM. A line of still larger Cumulus had formed to the west, indicating more moistening and “de-stabilization” of the air. However, the upper low was not advancing toward us any longer and no further development occurred as stagnated, ratcheting up its rainband over eastern Cal and western AZ. The TUS balloon sounding suggested tops were getting close to the normal ice-forming level here, -10 C, the slight inversion on the morning sounding at 13,000 feet above sea level, and the one likely to have caused those smooth morning clouds, was gone.

6:07 PM. Just before sunset from near Oracle where we took mom for her BD. The heavier Cumulus clouds faded with the sun. They will arise today!

Below, just some pretty patterns observed later in the day. Click to see larger versions.

3:36 PM. Twisted, tortured Cirrus (fibratus?).

3:50 PM. Another view of Cirrocumulus. Though these clouds are still composed of liquid droplets, the 5 PM TUS sounding suggests they were at about -30 C in temperature. It happens.

4:00 PM. An incredibly complex array of Cirrocumulus overhead. Due to perspective, its about the only view that you can really see how complex the patterns are.

6:22 PM. Finally, from the "Not taken while driving since that would be crazy" collection, this oddity. Looks like an high temperature contrail (aka, "APIP"). but the trail seems to shoot up into the cloud Altocumulus cloud layer (or down out of it). Have never seen this before. — 6:22 PM. Finally, from the “Not-taken-while-driving-since-that-would-be-crazy-though-it-looks-like-it-was” collection, this oddity. Looks like an high temperature aircraft contrail (aka, “APIP”) in the lower center. And the trail seems to shoot up into the cloud Altocumulus cloud layer (or down out of it). Have never seen that kind of aircraft track before since it looks so steep! “High temperature” here means that it formed at temperatures above about -35 C.

Whew, the end.

——-

¹Not!!!!!! I thought this was a good read about this deplorable new stage of “climate thought enforcement” now in progress. It was brought to my attention by climate folk hero, friend, and big troublemaker, Mark Albright. Wow, maybe Mark will be investigated, too! Maybe I should excise his name….

²I remember, too, how cute she was when she worked my lab/office at the University of Washington in the mid-1980s, and thought about asking her out, to detract from a serious commentary here. She was a Penn State grad student, not a U of WA employee; still, to ask her out would have been untoward. A human commentary like this, one about feelings and things, help boost blog attendance.

Such a morning, such an evening; lots in between

1) Let yesterday morning’s color show speak for itself, just incredible, speaking for it anyway.

2) Please review the U of AZ time lapse film here to understand why it takes the biggest computer Fujitsu can build to calculate what the atmosphere is doing. Also reviewing this let’s you escape from the tedium about to be presented below.

3) Expect a similarly photogenic day today.

6:42 AM. Altoculumulus lenticularis downstream from Catalinas. Thought I would misspell Altocumulus to see if anyone is reading this. Sun seems to be coming up earlier and earlier.... — 6:42 AM. First light, this incredible scene. Altoculumulus lenticularis downstream from Catalinas. Thought I would misspell Altocumulus to see if anyone is reading this. Sun seems to be coming up earlier and earlier….

6:42 AM. Looking to the left or north of the lenticular.... — 6:42 AM. Looking to the left or north of the lenticular….

6:44 AM. That leniticular again, the bottom structure now highlighted. — 6:44 AM. That lenticular again, the bottom structure now highlighted.

6:49 AM. What can you say? So pretty all around. Another lenticular was in progress to the main one.

6:53 AM. If the scene wasn't spectacular enough, an iridescent display then occurred to enhance it even more. — 6:53 AM. If the scene wasn’t spectacular enough, a display of iridescence (rainbow colored area) then enhanced the original Ac len even more. It doesn’t get better than this and I hope you saw it “live.” I was just beside myself, taking too many photos, losing control, rationality.

8:28 AM. Both lenticulars still in place, but now augmented by a layer of Altocumulus perlucidus (honey-combed look) and a scruff of low clouds that topped the Catalinas marking the invasion of a low level moist air. The feel of rain was in the air then, too.

8:28 AM, the same time as the prior photo, but looking upwind over Oro Valley, toward Marana and beyond at a line of Stratocumulus, with Altocumulus perlucidus and patchy thin Cirrus above those. Even here, the scene seemed exceptional.

9:41 AM. That Altocumulus deck began arriving overhead and you could see the little "heads" trailing ice crystals like comets with long tails. When the heads are gone, you'd call it Cirrus and never know how it got those fine strands. — 9:41 AM. That Altocumulus deck began arriving overhead and you could see the little “heads” trailing ice crystals like comets with long tails. When the heads are gone, you’d call it Cirrus and never know how it got those fine strands. In the meantime, the Stratocumulus and Cumulus clouds were slowly getting deeper.

1:19 PM. Stratocumulus was becoming the dominant cloud form. No ice, no precip, too warm, droplets in them below the Hocking-Jonas Threshold for collisions with coalescence. — 1:19 PM. Looking over Catalinaville¹: Stratocumulus was becoming the dominant cloud form. No ice, no precip, too warm at top; also, largest droplets in them below the Hocking-Jonas Threshold (30-40 microns in diameter) for collisions with coalescence to occur, if you care to learn things.

3:42 PM. One of the many pretty scenes yesterday, these Altocu perlucidus, no ice. So, much warmer and lower than those trailing ice in the earlier photo.

4:19 PM. Then, as the Stratocumulus filled in again, we got our late afternoon "light show", those drifting spots of sun illuminating our mountains, though here our own Sutherland Heights subdivision, if that is what it is. So pretty. — 4:19 PM. Then, as the Stratocumulus filled in again, we got our late afternoon “light show”, those drifting spots of sun illuminating our mountains, though here our own Sutherland Heights subdivision, if that is what it is. So pretty.

5:19 PM. Can't be inside when this is going on.... Have problem. — 5:19 PM. Can’t be inside when these scenes are happening…. Have problem.

6:13 PM. That sunset glow we see on our mountains every day, except a little more dramatic when dark clouds are overhead.

6:19 PM. The day finished as gorgeous as it began as a clearing to the far west allowed the sun to light the bases of the overhead Stratocumulus layer.

The rain just ahead

Rain masses will be forming to west of Catalina today and will pound eastern Cal and western AZ for about 24 h before roaring in here tomorrow morning. Staying the course, best guess, from extremes of at least 0.33 to a max of 1.50 here, is 0.915 inches (the average of the worst and best case scenarios) here in “Catalinaville” as the total amount from this “hit” tomorrow and the showers afterwards into later Tuesday, as a second storm part comes by. Thunder tomorrow seems likely from this keyboard as the big rainband goes over.

During the passage of the rainband tomorrow, rainrates are likely to get up to an inch an hour, at least briefly, (this is the rate, NOT the duration) and typically, with several hours of moderate (0.1 to 0.3 inches per hour) to heavy rain (greater than 0.3 inches per hour) we should get a nice drenching.

The weather way ahead, 10 days or more

After a long dry spell following this upcoming rain, spaghetti is strongly indicating we have more troughiness in our future after the temporary dry spell!

Check it out, spaghetti connoisseurs²:

Valid at 5 PM, March 11th. Note clustering of red and blue lines in trough off Cal. — Valid at 5 PM AST, Saturday, March 11th. Note clustering of red and blue lines in trough off Cal.

Ann for Sunday March 15 spag_f360_nhbg — Valid at 5 PM, Sunday, March 15th. Southward bulging red lines, so many of them, indicate a very good chance of a trough here at that time. Blue lines, for a colder part of the jet stream, also tend in this direction, a good sign.

The spaghetti plots, taken together, indicate to the present Arthur that the chance of rain twixt spaghetti 1 and spaghetti 2 shown above is about 70%. It will be extremely FUN to see if this interpretation works out for rain between March 11-15th, at least one event anyway, to continue overusing that word.

The End, finally.

—————————————–

¹Didn’t Jimmy Buffet do a song about Catalinaville? Has a nice ring to it. Maybe we should think about it… Or maybe, in a vein similar to Carmel-by-the-Sea, “Catalina-by-the-Catalinas.”

²Remember, spaghetti is better than the model in the medium range forecasts that are presented based on the global data. Spaghetti is there to help you decide whether that model output is from the WRF-GFS looney bin or not. Here’s how:

Spaghetti is the result of DELIBERATE little errors put into the model when they start crunching the data to see how the forecast that you see on the maps could go wrong if there are errors in the data.

Of course, there are ALWAYS errors in the data! So, when the Fujitsu Computer DIvision made gigantically capable computers for us that were better than the ones we could make, ones that could do teraflops per second, we in the weather community could then run many permutations of the same model with itty-bitty errors in the initial data to see how the results changed (diverged) in the longer term.

Remember, too, in weather itty-bitty differences can add up to large ones in the longer term. So, when the model permutations with little errors cluster and DON’T diverge, it provides more confidence that the forecast storm, for example, is more likely to happen in that fuzzy forecast range of beyond 10 days or so. End of giant footnote.

No clouds of note yesterday, so no blog today

But, on second thought, people who have nothing to say, often say it anyway….and that’s pretty much what happens here everyday anyway….to repeat “anyway” again anyway.

Things continue to roll along for a juicy dump of rain, snow and wind beginning here on Monday.

Its windy outside now.

OK, a coupla clouds from yesterday….

8:15 AM. Pretty Cirrus fibratus (has delicate strands, filaments of falling ice crystals).

12:15 PM. "Micro" snowstorms. I bet Boston folk would like to have these instead of the ones they've gotten. — 12:15 PM. “Micro” snowstorms. Look at the snow trailing down! It would be composed of itty-bitty crystals (a couple of hundred microns in maximum dimension), probably “bullet rosettes.” I bet Boston folk would like to have these snowstorms instead of the ones they’ve gotten.

4:00 PM. There were some Cumulus fractus, poor guys never even got to the humble or "humilis" stage. You should still have logged them in your cloud diary, however. — 4:00 PM. There were some Cumulus fractus, poor guys never even got to the humble or “humilis” stage. You should still have logged them in your cloud diary, however. Note the horrific vertical wind shear here as indicated by tops being ripped off to the left, showing how much the wind increased with height from the bottom to the top of even these shallow clouds. I guess I can’t expect you to have a sophisticated comment like that in your diary, but would hope for it.

6:20 PM. Some Cirrus eye candy. Sunset seems to be happening later and later. — 6:20 PM. Some Cirrus eye candy for you. Sunset seems to be happening later and later.

The End

Phony Cu fractus hint at moderate to severe turbulence aloft; the BS ahead

Immediately, “BS” is for “Big Storm” ahead, not something untoward.

OK, first a piece about yesterday’s unusual clouds at Cirrus levels; you wouldn’t want to be flying in, or underneath these:

1:25 PM. Suddenly, a patch of phony Cumulus fractus appeared at Cirrus levels! I wondered how many CMJs were fooled and thought these clouds were just a little higher than Ms. Lemmon's top. — 1:25 PM. Suddenly, a patch of phony Cumulus fractus appeared at Cirrus levels! I wondered how many CMJs were fooled and thought these clouds were just a little higher than Ms. Lemmon’s top.

1:25 PM. Zoomed view of phony Cumulus fractus.

1:26 PM. Compare to real Cumulus fractus, and the imitation, knock-off, phony, generic brands like to say about the real thing, and they're not as good are they. They don't think that you're REALLY going to compare them and that's why they say that. — 1:26 PM. “Compare to real Cumulus fractus,” as the imitation, knock-off, phony, generic brands
like to say about the real thing you like, but they’re never as good are they? They don’t think that you’re REALLY going to compare the real one with the phony one and that’s why they say that. They think you’re lazy. I’m thinking of Danny Elfman¹ and “Grey Matter”…..

1:46 PM. Here CMJs can easily tell that those clouds, though they appeared tufted and like they might have had droplets, were at ice-forming levels high in the atmosphere. That height also indicated by their luminosity, whiteness, as they first formed. — 1:46 PM. Here CMJs can easily tell that those clouds, though they appeared tufted and like they might have had droplets in them when they first formed, were at ice-forming levels high in the atmosphere. Here you see the expanding “ghosts” of several of the tufts that formed (upper left center), originally a dense concentration of ice crystals or a momentary droplet cloud, a dense cloud of ice that disperses in time, no further ice forms and so acts like a puff of smoke, and thins out, often disappearing as some of these did.

You can also these specks fly by in the U of AZ time lapse film. If you look at the film when they do, you can see them twisting around. Cirrus at that level (CM estimated 25,000 to 30,000 feet above the ground) are normally like sculptures; frozen in time as they pass by this time lapse camera with little or no internal movement.

You could also detect internal movement from the ground in real time in these specks (as we can with Cumulus clouds all the time, since we’re so close to real Cumulus fractus) so it must have really been churning up there.

This patch of specks only took a few minutes to pass by, so you were lucky if you say them.

Of course, you’re only interested in the Big Storm just ahead, not turbulence….probably have grown impatient by now, not wanting to read about itty bitty specks in the sky that might have been associated with strong turbulence. Well, its still “in the bag”, no need to worry. See below this map from our Canadian friends’ model. I really like this map, so no need to look farther. Also, I wrote some things on it for you:

Valid for Monday, 5 AM AST, March 2nd. I just had to go, "wow" when I saw this forecast map. — Valid for Monday, 5 AM AST, March 2nd. I just had to go, “wow” when I saw this forecast map.

That “kicker” trough just off the Cal coast is going to kick that trough “ball” just off Baja at us as in a field goal in American football, and we are the goal posts.

When a trough is booted out like this one will be out of its nest, the upward motion in front of it is in enhanced, so that the clouds and precip intensify, become more widespread. Its going to head right for us, as it accelerates toward the NE.

This means, in turn, that the very strong rain band already in place in western Arizona, will intensify as it moves east across the State. This is pretty darn exciting because from here it would mean quite the downpour, hours of rain, and almost certainly thunderstorms on March 2nd. However, flooding is likely as rainrates will likely get up to an inch an hour or even more as the band passes over us.

Still sticking with 0.9 inches as “best guess” here in Catalina, top amount, 1.50 inches, if band lingers longer. Secretly hope I’m low….

In one last forecast panel, this MONSTER approaching the Cal coast. Its pretty far out there, as I am being today with the notes on band favorite, Oingo Boingo and sociobiology below, to be reliable, but its shown up a couple of times now in our model runs. It is unbelievable in strength to be forecast as far south as off central Baja, and I wanted to show you what an amazingly strong storm for so low in latitude would look like, if nothing else:

Valid at 11 AM AST, March 11th, Wednesday. A trough from this low a latitude barging into southern California would likely bring rains of 10-20 inches. And, while we’re downwind behind mountains, it would still bring appreciable rain here, too. BTW, rains of 10 inches or more, even in just 24 h, are not terribly unusual in the mountains of southern Cal.

The End.

PS: A powerful jet stream is near us now, so more strange clouds, lenticular-sliver clouds, and fine granulations in Cirrocumulus and such, are likely to be seen over the next couple of days. Have camera ready.

PPS: Still some flow in the Sutherland Wash as of yesterday.

——————————-

¹The genius of Danny Elfman, that is, composer of the Simpson’s theme song, and the only composer to be nominated for two film scores in the same year, and also the leader of Oingo Boingo, an LA punk rock/ new wave band in the early 1980s, formerly known as , “The Mystic Nights of the Oingo Boingo”, more like a Spike Jones gag band. An early influence on Elfman was the concept of sociobiology, as represented in “Only a Lad“, a song about an inherently bad “lad”, satirizing some popular, widely held concepts on the causes of mischievous behavior in that song. A sample below, if you care².

“The lady down the block,
She had a radio that Johnny wanted oh so bad,
So he took it the first chance he had.
Then he shot her in the leg,
And this is what she said
“Only a lad. You really can’t blame him.”
“Only a lad. Society made him.”
“Only a lad. He’s our responsibility.”
Oh, oh, oohh oh oh oh
“Only a lad. He really couldn’t help it.”
“Only a lad. He didn’t want to do it.”
“Only a lad. He’s underprivileged and abused.”
Perhaps a little bit confused?”

²Being a rad-lib in those days, I thought it was INCREDIBLE to hear such a song with THOSE lyrics in the early 1980s on the University of Washington student radio station, KCMU-FM, again, if you care.

I think you should see this…..

This just out from Weather Underground:

From the de facto National Weather Service, Weather Underground — From the de facto national weather service, Weather Underground, extraordinary details of our upcoming storm days.

Even more rain that CM’s top amount of 1.5 inches (less than 10% chance of more)! Amazing. (Not changing mine, though; best to ride it out, stay the course…..)

Note, too, the accuracy of WU forecast to hundredths of an inch! Wow.

The weather WAY ahead

With “Stormy Weather One” now bagged as a sure thing twixt March 1 and 4, let us turn our attention far into the future….and see one of the great forecast maps of our time:

Valid at 11 AM AST, March 12th. Based on global data taken at 11 PM AST last evening, crunched by WRF-GFS.

Shows gully-washin’, drought bustin’, tropical air-filled storm crashing into the parched Southwest. Only 13 days from now, too, so it might happen. We get a lot, too, in this storm sequence rendered by MeteoStar.

The End

Moving along; rain to fall in early March (a lot of it)

In fact, the chance of MEASURABLE rain in Catalina is at least 100%, maybe as high as 300%, between 5 AM AST, Sunday, March 1st and 5 AM, AST, March 4th. Namely, its gonna happen.

Now, its not gonna rain that whole time, likely starting later in the day on the 1st. Pretty darn exciting to have a sure thing in the future! Check out this 4-panel presentation of maps from Enviro Can, I really like them:

Valid for Monday, March 2nd. Heavy rains foretold in western AZ by this time. Likely will be here by this time, too, though THIS model thinks the rain is still to the west.

Perhaps going farther than one reasonably should, the likely minimum amount will be 0.33 inches (10% chance of less) and top amount, gee, this situation has a big top, 1.50 inches, due to this trough’s deep reach into the sub-tropics, meaning it could pulling extra wet air toward us if everything works out in the “best” possible scenario. The best guess, between these two extremes is the average, or about 0.9 inches during our rainy spell. Should keep the washes flowing, though this one being colder than January’s tropical rains, should pile up lots of snow on top of Ms. Lemmon, so

Moving ahead to yesterday……

A pretty nice 0.09 inches fell yesterday morning in The Heights. “Nice”, because some model runs a few days in advance of this had no rain as a dry cold front went by.

When did the cold front pass?

9 AM yesterday, marked by a freshet from the NW with gusts to maybe 20 mph, with a falling temperature. Fell from 51 F to 42.x F by mid-morning, snow down to about 5,000 feet on Samaniego Ridge, too, though it melted almost immediately.

A push of wind like that virtually always builds a cloud above it, and yesterday was no exception. Here’ the cloud associated with that “freshet”:

8:31 AM. Wind shift line cloud shows up NW-NE of Catalina. Get ready!

8:32 AM. Mini-rainbow appeared for just a moment.

8:34 AM. Tiny holes in clouds produce pretty highlights on Eagle Crest as the windshift line cloud approaches.

9:03 AM. Windshift and line cloud pass over Sutherland Heights. Starting to rain here, though very little.

9:03 AM. Close up of the bottom of the windshift line cloud.

12:39 PM Post frontal passage quiet time with flattened clouds.

1:28 PM/ Clouds swell up, first ice seen. Can you find it? More to north at this time.

2:24 PM. Lots of pretty cloud "streets", Cumulus clouds aligned in a line. Here's a common one that comes off the Tortolita Mountains on Cumulus formation days. — 2:24 PM. Lots of pretty cloud “streets”, Cumulus clouds aligned in a line. Here’s a common one coming at you, one that comes off the Tortolita Mountains on Cumulus formation days with a westerly wind in the boundary layer (the layer between the ground and the tops of these clouds).

3:19 PM. Walkin' dogs, ice overhead in that SAME cloud street coming at me. Uh-oh. — 3:19 PM. Walkin’ dogs now, but spotted trace of ice overhead in that SAME cloud street coming at me from the Tortolitas. Uh-oh. Do you see the trace of ice up there?

3:21 PM. Few raindrops beginning to fall. Can you detect that bit of a rain haze on the left of this photo, out toward the Torts? — 3:21 PM. Few raindrops beginning to fall. Can you detect that bit of a rain haze on the left of center in this photo, out toward the Torts? Very hard to see, but there was an nearly invisible “shaft.”

3:33 PM. Tiny snow shaft hangs from this same cloud line as it began to shift to the south and east. Can you find it?

Of course, the best part of days like yesterday is the play of the light and shadows on our mountains:

5:58 PM. Stratocumulus clouds above the Charouleau Gap.

The End.

100-150 mph winds overhead bring pretty patterns in Cirrocumulus clouds; also, an experiment in detecting the phase of clouds

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!

3:47 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. — 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.

3:26 PM. The scene before the experiment. The upwind edge where the Cirrocu and CIrrus were forming is just above the horizon. — 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. — 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. — 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.

Today’s take

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.

The first of many cloud blobs in the days ahead, some rain-filled, passes over during the night

Here it is. You may need an optical enhancement tool to see the radar echo speck nearest Catalina, and its not the one nearest the arrowhead below, but continue in that direction:

Ann 201502230700_SWR2 — Satellite and radar imagery for midnight last night. Notice cloud blob and radar echoes over and near Catalina, Arizona. I really thought there’d be some drops here as this went over!

You can also check on all the rain that fell overnight in the region here, courtesy of Pima County ALERT rain gauges. BTW, they aren’t capable of reporting traces, so if you see bunches of zeroes, it doesn’t mean some drops didn’t fall somewhere in the network.

Non-verification of this rain can also be found via our fine TUS NWS “storm total” view, 10:30 PM to 4:30 AM this morning:

Regional radar-derived storm total from "rainy cloud blob." — Regional radar-derived storm total from “rainy cloud blob.” Arrow almost reaches Catalina; didn’t want to cover up a pixel of rain, if there. THAT radar did not pick up the rain I feel must have fallen, so we have quite a conundrum. If you would like to see for yourself how much rain fell last night, go here. Will be looking for drop images in the dust as soon as it gets light, too!

In the meantime, all those rainy cloud blobs to our NW right now (first image) look like they will be able to just make it to Catalinaland after all.

In our last chapter, it looked like the strong cold front would move through tomorrow as just a dry cold one, but now the chances of having a little rain (a wet cold one) have been zooming up. The models have readjusted their thinking and now that critical ingredient, the core of the jet stream (at 500 mb) passing over us ahead of the trough core itself is being predicted.

And with that configuration as the front goes by Catalina, and believe me you’ll know by the 10-15 degree temperature drop, a tiny amount of rain might fall. Also, look for a pronounced lowering of cloud bases to the W-N of Catalina as it gets close, something in the way of an “arcus cloud”, marking the leading edge of the windshift to the N. Could be nice and dramatic looking tomorrow. Those cloud base lowerings are pretty common with fronts here.

How much rain?

Oh, possibilities range between 0 (a complete bust is still possible) to only about 0.25 inches, tops in the “best” of circumstances. But, this keyboard would like to see ANYTHING measurable; that would bring happiness.

There are some more rain blobs showing up in regular intervals in the days ahead for you to think about, as rendered by IPS MeteoStar. Arrows have been added to show you where you are, if you are in SE Arizona:

Valid tomorrow morning at 11 AM AST. Colored areas denote regions where the model has calculated precipitation during the preceding 6 h.

In the storm below, which is pretty much going to happen now, the range of amounts as seen from here, at least 0.15 inches, top, 0.50 inches, best guess, therefore, 0.33 inches (from averaging the two.)

Val at 11 PM, March 1st. Colored areas are those in which the model has calculated that precip has fallen during the prior 6 h.

There’s great uncertainly in whether this last storm will actually occur, so range of amounts are zero to 1 inch. :} See reasons for uncertainty below, besides being too far in advance or our models to be reliable anyway.

Ann 2015022300_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_264 — Valid Friday, March 5th, at 5 PM AST. Colored regions NOW denote areas of precipitation that have fallen during the prior TWELVE hours. (Mod resolution degrades after about 192 h, and so a coarser view of precip areas is used.)

While a significant storm on the 1st is virtually assured according to spaghetti, this last major event in the panel above is doubtful. See below, in another lesson on consuming weather spaghetti:

Ensemble spaghetti valid for the same time as the panel above, 5 PM AST Friday, March 5th. Not much support for a storm, low confidence is indicated by the LACK of bunching red and blue lines, unlike those off the East Coast, and over there east of Asia. So, while a great storm is predicted in last evening’s model run, prepare for sadness and disappointment as a hedge.

Yesterday’s fine clouds

7:10 AM. A couple of shafts of big virga. Likely a drop or two reached the ground. Could have been caused by aircraft penetrations, or, taller Altocumulus castellanus-like turrets that reached lower temperatures, produced more ice. They look suspiciously like an aircraft artifact due to their very small size.

7:41 AM. Nice stack of lenticular pancakes in the lee of the Catalinas. You can see some great lenticular occurrences in the U of AZ Time Laps movie for yesterday. There are also a lot other fascinating things that go on in yesterday’s clouds, too.

8:05 AM. Natural virga approaches Catalina. Looked for a drop as it went over, but saw none. — 8:05 AM. Clearly natural virga approaches Catalina. Looked for a drop as it went over, but saw none.

8:22 AM. Pancakes downstream from Ms. Mt. Lemmon.

9:07 AM. Doggies, Emma, and little Banjo, sample and inspect water STILL running in the Sutherland Wash!

1:46 PM. After a brief sunny period, banks of Altocumulus invade the sky.

2:46 PM. Altocumulus opacus clouds continue to fill in, darken.

5:40 PM. Muliple layers of clouds stream ahead of sprinkle producing cloud blob just upwind at this time. — 5:40 PM. Muliple layers of clouds stream ahead of sprinkle-producing cloud blob just upwind at this time. Note how the Altocumulus opacus clouds disappeared, leaving lenticular like formations, with a thin ice cloud (Cirrostratus) above.

The End, though I COULD go on and on and on, and then on some more. Its who I am….

Watch for pretty clouds today, tweet

5:41 AM: “Tweet” Patch of big virga, sprinkles, now in progress SW of Catalina. Could make for a spectacular sunrise if more of that is around.

5:43 AM: “Tweet”: Banks of heavier, middle clouds and high clouds expected to arrive later in day. Forming off Baja now.

5:45 AM: “Tweet”: Still expecting a trace to maybe a tenth of an inch from that system off Baja by mid-day tomorrow.

5:46 AM: “Tweet”: Major cold front goes through tomorrow night or Tuesday but looks dry now with just a big change in temperature. Izzat more that 140 characters?

5:49 AM: “Tweet”: Still thinking about weather things and what to say next.

5:50 AM: “Tweet”: It wasn’t me that fell off that horse with a riding pal, in case you were worried about me, though I ride in that area.

5:51 AM: “Tweet”: Brain still pretty empty.

5:52 AM: “Tweet”: Still waiting for something to enter brain.

5:53 AM: “Tweet” OK, just thought of a joke. See below.

5:56 AM: “Tweet”: OK, its a sophisticated weather joke.

5:58 AM: “Tweet”: Arrow points to today’s little cloud maker, but mods pretty clueless about where it is from the get go; how funny izzat? Can I tweet and use a semi-colon?

6:02 AM: “Tweet”: Have cameras ready!

6:03 AM: “Tweet” Brain empty again. Reminds me of that song, “Running on empty.” Feels just like that. Maybe that will distract some people while I think of something.

6:04 AM: “Tweet”: I haven’t added anything but will update anyway.

6:08 AM: “Tweet”: Rain still expected in March.

6:09 AM: “Tweet” The End.

Not to worry; plenty of model rain still ahead in models

¹While several inches of model² rain has occurred in Catalina and in the nearby mountains this month, most of which cloud-maven person has festooned his blog with model panels of, there really hasn’t been any ACTUAL rain.

But having said that, there is even MORE model rain ahead, some beginning tomorrow in these parts. Tomorrow’s rain comes from a sub-tropical minor wave ejecting from the sub-tropics. You know, as a CMJ, a wave from that zone means a ton of high and middle clouds, i.e., likely DENSE Altostratus with virga, something that was seen yesterday off to the SW of us. This time, though, some rain should fall from these thick clouds, though almost certainly will be in the trace to a tenth of an inch range between tomorrow and Monday morning.

Model rain from 11 PM AST global data then falls in Catalina on:

February 24th

March 1st

March 7-9th

with the model total rain in these periods likely surpassing an inch or more! What a model rain winter season this has been! Astounding. The model washes have been running full since late December, too!

BTW, that last model rain period is really a great one, a major rain for ALL of Arizona!