Category Archives: Cirrus clouds

This is a new category

More patterns galore, but with natural holes in them that made for an extra fascinating day!

The TUS balloon sounding launched at around 3:30 PM from the Banner University of Arizona
The Banner NWS TUS balloon sounding launched at around 3:30 PM from the Banner University of Arizona.  The temperature of the Cirrocumulus was indicated to be about -36° C, at about 26,000 feet above Catalina (29,000 feet ASL) and yet portions of the Cc had liquid droplets.  The higher vellums of Cirrostratus or Cirrus were located.

Photos of yesterday’s patterns

I could literally hear the cameras clicking all over Catalina and Oro Valley as these patterns showed up, moving in from the southwest as the increasing numbers of cloud-centric folk lost control of themselves.  Reflecting that general loss of control, which affected yours truly, too many photos will be posted here.  Below holey clouds with icy centers, but not ones caused by aircraft:

DSC_3203 DSC_3201 DSC_3198 DSC_3197 DSC_3187 DSC_3186 DSC_3181

And look closely at the fine patterns, lines and granulations in these shots!  Truly mesmerizing.

DSC_3222 DSC_3221But what’s missing in this photo above?  There was no iridescence seen around the sun where we normally look for it suggesting that those Cirrocumulus clouds nearest the sun were composed of ice crystals, and not tiny droplets.    Iridescence is rarely seen next to the sun due to ice crystals because they are usually the result of the freezing of existing droplets, that then grow rapidly as ice particles to sizes too large to produce diffraction phenomenon  close to the sun.  Where’s my Lear jet,  so’s I can confirm these speculations?!!  I would very much like to have one on “stand by”, in case I think of something.  Below, a wonderful example of no iridescence even though newly formed clouds are by the sun:

4:21 PM. An outstanding example of no iridescence, maybe one of the best ever taken!
4:21 PM. An outstanding example of no iridescence, maybe one of the best ever taken!  The power pole shows signs of being in an archaic neighborhood.

A jet runs through it

Or so I thought.  In this chapter of cloud-maven.com, we inspect the photos of a commercial jet flying at or near the level of these clouds and determine what happened.  I was quite excited to see this happen because we would now determine whether there were any liquid droplets in what to the eye of the amateur cloud watching person would be a liquid droplet Altocumulus clouds.  Here the size of the elements are just a bit too large to lump it into the Cirrocumulus category, if you care.  So, with heart pounding, took this sequence of photos:

4:23 PM. A commercial jet streams into it seems, the Altocumulus layer. Or did it? CMP thought so.
4:23 PM. A commercial jet streams into it seems, the Altocumulus layer. Or did it? CMP thought so.

Let is go zooming:

4:23 PM. Looks to have descended to below this layer. Note sun glint on aircraft.
4:23 PM. Looks to have descended to below this layer. Note sun glint on aircraft.
4:23 PM. Zoomin' some more.
4:23 PM. Zoomin’ some more.
4:26 PM. But, as the location of the aircraft path slipped downwind rapidly, there was NOTHING! I could not believe it! No ice canal with a clearing around it, and no contrail inside these clouds. The clearing would have occurred had the aircraft penetrated supercooled droplets leaving an ice canal. But, if the cloud was all ice, a penetration by an aircraft should have left a contrail, as they do in cirriform clouds. The conclusion? As close to this layer as the aircraft was, it did NOT apparently go into it. Amazing to this eye.
4:26 PM. But, as the location of the aircraft path slipped downwind rapidly, there was NOTHING! I could not believe it! No ice canal with a clearing around it, and no contrail inside these clouds. The clearing would have occurred had the aircraft penetrated supercooled droplets leaving an ice canal. But, if the cloud was all ice, a penetration by an aircraft should have left a contrail, as they do in cirriform clouds. The conclusion? As close to this layer as the aircraft was, it did NOT apparently go into it. Amazing to this eye.
4:25 PM. Looking downwind at those "Altocumulo-cirrus" clouds, all ice from almost the very leading, upwind edge due to that -36°C temperature they were at.
4:25 PM. Looking downwind at those “Altocumulo-cirrus” clouds, all ice from almost the very leading, upwind edge due to that -36°C temperature they were at.  Though overhead, as you saw in the photos below, they might be reckoned as plain Altocumulus, and not solely composed of ice ones.

By the way, if you caught it, there were a couple of standard, aircraft-produced, “hole punch” clouds at the very upwind, formative portion of this patch of clouds before it got here. These photos pretty much prove that the Cc at the formative end at that time was composed of highly supercooled droplets and that the passage of an aircraft produced ice, that caused a fall out hole.

1:52 PM. Hole punches caused by aircraft in the Cirrocumulus to Cirrus patch that moved over us later. Clouds like these do not move at the speed of the wind, about 60mph up there yesterday at this level, but rather, the air moves through it a hump in the airflow that moves much more slowly than the wind.
1:52 PM. Hole punches caused by aircraft in the Cirrocumulus to Cirrus patch that moved over us later. Clouds like these do not move at the speed of the wind, about 60mph up there yesterday at this level, but rather, the air moves through it a hump in the airflow that moves much more slowly than the wind.  Note the slight iridescence in the hole on the right.

 

The End–quite enough, eh?

High cold ones, and lots of patterns in a complex sky

In particular, those Altocumulus clouds, “cold” Cirrocumulus (ones that transform to ice immediately),  and those “Altocumulocirrus” clouds combining  with  scenes of “regular” cirriform clouds.  Lots of interesting sights to have seen yesterday.  All these the result of marginal moisture aloft and strong winds, up around 100 mph at the highest Cirrus levels.

Let us begin as cloud maven folk by examining the late afternoon sounding launched from our Wildcat balloon launching machine at the University of Arizona, courtesy of IPS Meteostar:

The temperature and humidity profile obtained from a weather balloon launched at about 3:30 PM yesterday afternoon from the U of AZCats.
The temperature and humidity profile obtained from a weather balloon launched at about 3:30 PM yesterday afternoon from the U of AZCats with some suggested cloud levels.  The Altcoumulus level is in doubt. the others are pretty straight forward.  Notice how high those little Cu were yesterday afternoon, about 16,000 feet above sea level, or about  13,000 feet above Catalina, with bases at a cold -13°C or so.  No ice came out of those, though.  Likely droplets too small, or short-lived.
DSC_3122
6:45 PM. A very narrow line of Altocumulus castellanus and floccus virgae approaches Catalina.
DSC_3123
6:46 PM. Let us exercise our curiosity and examine this element in more detail below.
6:47 PM. Altocumulus floccus virgae. Another example of how the top of a storm, as here, can be composed of droplet cloud while the ice that forms in it falls out below. Here, the extreme dryness underneath the Altocu prevents long trails. The ice crystals wither so that they have almost no fallspeed soon after they have fallen out, leaving a flat bottom of tiny ice crystals.
6:47 PM. Altocumulus floccus virgae. Another example of how the top of a storm, as here, can be composed of droplet cloud while the ice that forms in it falls out below. Here, the extreme dryness underneath the Altocu prevents long trails. The ice crystals wither so that they have almost no fallspeed soon after they have fallen out, leaving a flat bottom of tiny ice crystals.  When you see tiny cloudlets like this spewing ice, you KNOW that the temperature has to be extremely low, and colder than -30° C (-22°C) would be a good starting guess.  Actually, guessing “-31.3° ” would be more impressive to your friends or neighbors….   It was a pretty scene, that’s for sure.
5:37 PM. Pretty iridescence occasionally erupted in newly formed Cirrocumulus, newly, as within seconds or in the last minute when the cloud droplets are extremely tiny, less than 10 microns in diameter. You don't see iridescence in clouds with droplets much larger than that.
5:37 PM. Pretty iridescence occasionally erupted in newly formed Cirrocumulus, newly, as within seconds or in the last minute when the cloud droplets are extremely tiny, less than 10 microns in diameter. You don’t see iridescence in clouds with droplets much larger than that.  And, it has to be pretty much overhead to get the best views.  Hope you saw those yesterday.
5:41 PM.
5:41 PM.
5:43 PM. ??????? These are little cloudlets of ice up at Cirrus levels, but it looks exaclty like a field of normal Altocumulus to the ordinary eye. "Altocumulocirrus"?
5:43 PM. ??????? These are little cloudlets of ice up at Cirrus levels, but it looks exaclty like a field of normal Altocumulus to the ordinary eye. “Altocumulocirrus”?  Without doubt this “ice” composition would be contested by other observers.  However, cloud-maven person’s interpretation should be used.  Now it is likely that the ice in these clouds first formed on what we deem as “cloud condensation nuclei”, and it might be likely that water saturation was reached.  But, if there was an instant of liquid, is certainly transitioned to ice in seconds since the temperatures at Cirrus levels were well below -40° C.   I don’t believe this was at the same level as the Altocu shown in the beginning of this writeup, yet it wasn’t as high as the highest Cirrus yesterday (up around the -50° C level).
6:07 PM. An example of how complicated the cloud scene was yesterday. The whitish clouds in rolls were icy cirriform clouds, and the delicated clouds were HIGHER Cirrocumulus and Cirrus. Cirrocumulus yesterday was indeed where most cloud schematics put it, at Cirrus levels, though probably half the time its in the mid-levels were Altocumulus clouds reside. So, with Altocumulus-like clouds at Cirrus levels and Cirrocu on top of Cirrus, it was really a crazy cloud day yesterday.
6:07 PM. An example of how complicated the cloud scene was yesterday. The whitish clouds in rolls were icy cirriform clouds, and the delicated clouds were HIGHER Cirrocumulus and Cirrus. Cirrocumulus yesterday was indeed where most cloud schematics put it, at Cirrus levels, though probably half the time its in the mid-levels were Altocumulus clouds reside. So, with Altocumulus-like clouds at Cirrus levels and Cirrocu on top of Cirrus, it was really a crazy cloud day yesterday.  At the very top of this photo were Altocu that were immediately ice clouds that might have comprised a separate third level of clouds.  Need a Lear jet to get there fast to resolve these many guesses.
5:07 PM. Jumping around in time.... These were some of the best scenes yesterday IMO, those oh-so-delicate patterns in those cold Cirrocumulus clouds, ones that transitioned to Cirrus clouds downwind.
5:07 PM. Jumping around in time here…. These were some of the best scenes yesterday IMO, those oh-so-delicate patterns in those cold Cirrocumulus clouds, ones that transitioned to Cirrus clouds downwind.
5:08 PM.
5:08 PM. Same patch Cirrocu.  Note Cirrus forming in the lower portion of this photo, once Cirrocu.  BTW, all power lines should be placed under ground.
2:29 PM. Amid some real Cumulus fractus was some Cirrus "cumulus mimicry" I've termed "Cumulo-cirrus". Can you spot the fakes at Cirrus levels? Its pretty hard.
2:29 PM. Amid some real Cumulus fractus was some Cirrus “cumulus mimicry” I’ve termed “Cumulo-cirrus”. Can you spot the fakes at Cirrus levels? Its pretty hard.
2:29 PM. OK, I give up. Here's a zoomed shot of Cumulus fractus mimicry by clouds at Cirrus levels. Might have been some droplets, too, before converting to ice.
2:29 PM. OK, I give up. Here’s a zoomed shot of Cumulus fractus mimicry by clouds at Cirrus levels. Might have been some droplets, too, before converting to ice.  These kinds of clouds suggest significant turbulence at this level, as would be in a regular Cumulus fractus cloud.

The weather way ahead

Still looking for that chance of rain before July….  haha

Troughy conditions will actually recur aloft over us over the next few weeks it seems, which means slight chances of rain, but periodic cold fronts passing by, mostly dry ones.  Best chance for rain still seems to be around the 20th, plus or minus a day or two, even though mod outputs have backed off that scene.  But, we have our spaghetti that tells us the models will likely bring back that threat around the 20th, even if some individual runs show nothing at all or only close calls.  We shall see if this interpretation has any credibility at all, won’t we?

Of note, Cal having big April in rain and snow after the gigantic January and February accumulations!  Looks like they’ll continue to get slugged by unusually strong storms, off and on, for another couple of weeks.  Water year totals are going to be truly gigantic.

The End

“Peru’s Niño”

I thought you’d like to read this (Peru’s Niño), forwarded to me by Niño expert, Nate M.   Pretty incredible to read about what is happening down there in the wake of the Big Niño of 2015-16,  which really turned out to be more of a couch potato in terms of weather production in the Great SW.

But, all this winter,  along the Equator near the coast of South America, there has been something we used to call an “El Niño”,  but is downplayed or ignored these days because of a new definition that seemed to explain more weather when it occurred, “Region 3.4” a large zone along the Equator WAY out in the Pacific rather than something near the South American coast (that zone now called, “Regions 1 and 2”),  as nicely illustrated by NOAA here.

But what has been the effect of what we might call the “Classic Niño”, a warm strip of water along the South American coast, one that doesn’t extend too far into the Pacific?  “Read all about it”, as they used to say.   Its pretty remarkable.

And here’s what the SST field looks like.  Its boiling down there off South America!  (Speaking figuratively, of course):

Sea surface temperature anomalies as of yesterday from the Navy!
Sea surface temperature anomalies as of yesterday from the Navy!  Wow.  That hot water is fueling giang Cumulonimbus clouds, ones that spew out huge anvils that can affect the weather in the mid-latitudes, disrupt the normal winter patterns of where highs and lows like to go.  Could such a warm anomaly, limited to the near coastal region of South America, have created this astounding winter in the West?

Peru’s Niño can be thought of as a “classic Niño”, the ones written about in the decades before about 1990 or so when the definition of what constituted a  NIño (or Niña) was expanded and delineated more sharply among several definitions that were floating around. We ended up focusing on a region WAY out in the Pacific Ocean called, “Region 3.4” that SEEMED to explain more over the prior years.

What’s so interesting about this is that the “Classic Niño” has been underway pretty much all this winter, and we’ve had, especially in California, a classic Niño response; that is,  abnormally heavy precip farther down the West Coast that no one anticipated.

Hmmmmm.

Well, the correlations with Cal precip and “classic Niño” occurrences will take a huge jump upward after THIS winter!

End of Statement (hand-waving)  on Niñoes.

——————————–

Local weather statement:  for immediate release

Cooler, fluctuating weather foretold here for that latter part of March, I don’t know how many weeks ago, is on the doorstep after the long, anomalously hot dry spell.  Poor wildflowers have been suffering, too, fading, looking a little stunted after a great beginning, one rivaling the great displays of 2010.

All of the local weatherfolk are on top of this now, and so no point recasting that stuff.  HECK, you can go to Weather Underground1
and get as “good as can be” forecast for Catalina (Sutherland Heights) out to ten days!  And, there’s nothing worse for a weather forecaster with forecasting in his blood, than to be excited about an “incoming” and when you mention it to a neighbor he replies, “Yeah, I heard about that already.  Supposed to get a quarter of an inch.”  There is no air whatsoever in the “balloon” after that.  So, if you have a weather-centric friend who says something about the upcoming weather, pretend that you haven’t heard about it yet, “DON’T say something as hurtful, as “Yeah, I heard about that already.”

So, here, we go the long route because most weatherfolk are afraid to go too far into the future because its often WRONG.  Our models tend to lie a lot after about even a week, so only the brave go out even ten days!

However, here, we go out as much as two weeks and more because its not a truly professional site but rather want to get something out there earlier than other people, sometimes called a “scoop” in the news and weather business.  That’s why our motto here is, “Right or wrong, you heard it here first!”  Furthermore, if a longer range forecast posted here is WRONG, you won’t hear about it anymore!

Cloud maven person will say this about the first incoming of several fronts:  comes in early Thursday morning, its strong!    Rainfall potential:  10% chance of less than 0.12 inches, 10% chance of more than 0.75 inches.  Best of those is the average, or about 0.4350 inches in this one.  It has great POTENTIAL to be a soaker, but mods have been all over the place; hence, the large range of potential amounts.  At least some measurable rain seems to be in the bag, a paper one please, because plastic is insidious.  Note, CMP’s forecast is more generous than that found in WU’s latest forecast for Catalinaland.

The weather WAY ahead, unprofessionally so

Let us look beyond the professional forecasting limits to April:

We know we got several storms/fronts zipping across AZ as March goes out like a lion, but what about April?

Looks like that pattern will continue into April with temperatures below normal for the first part.  The end of the unprofessional forecasting portion of this blog, though we do have our NOAA spaghetti to hang our umbrella on….  Check it out for about two weeks ahead.

Some clouds recent clouds, including a couple from yesterday

DSC_2744
2:33 PM.  Yesterday afternoon saw a few globs of lenticular forming on top of mini_Cumulus clouds, ones that made you think the summer rain season could be at hand, given the 90+ heat of yesterday around these parts.
12:52 PM.
12:52 PM.  A high  (above 30 kft above the ground) and cold (less than -40°C patch of Cirrocumulus cloud that is going to transition to CIrrus over the next 10-20 minutes.
DSC_2737
1:12 PM:  Later that same patch as those cloudlets spread out and merge into just an ordinary Cirrus after being that delicate-looking patch of Cirrocumulus. Most Cirrocumulus clouds are not this cold, but rather evaporate or fatten into larger elements of “Altocumulus” clouds, rather than transition to Cirrus.
DSC_2728
Had a nice sunset a couple days ago (15th), some liquid Altocumulus cloud slivers with higher Cirrus.

The End

———————–
1Although “Weather Underground” might sound like an org has a radical origin, maybe something left over from the late 1960s, this particular one was NOT formed by 60s “weatherman” terrorists like Bill Ayers and Bernadine Dohrn (the link is for those of you who may have set trash cans on fire, as happened at San Jose State to protest the Vietnam War, to look back at those days in horror or nostalgia; take your pick) , but rather by genuine weather geeks (haha, I count myself among them, those that can’t get enough of weather, there can never be too much, like the guys mentioned in this “Cloud City” article.)

Catalina WY progress report; Cal WY update, too, since I grew up in Cal

I thought you’d like to see this:

As of the end of February 2017. We're pretty average, but it took some "heavy lifting" in December and January to get there.
As of the end of February 2017.  You can see were right about at the average for the Water Year,, but it took some “heavy lifting” in December and January to get there.

Doesn’t look promising for much rain here in Catalina in March, however.  No rain in sight through the next 10 days at least.

Let’s check our 7 inches with what’s happening upwind, say, in CALIFORNIA, and see if there’s been any drought relief there, through February,  via the CNRFC:

California water year totals through the end of February 2017. Note one station in the central Califorina coastal range is already over 100 inches!
California water year totals through the end of February 2017. Note one station in the central Califorina coastal range is already over 100 inches!  There are 20 stations already over 100 inches as can be seen from the table at right.  March looks to have substantial rains north of SFO, which will add appreciably to those highest totals.  Amazing!  You can go to the CNRFC and expand these interactive maps, btw.

As you are likely to know from many media stories last year, Cal was in a drought siege of five straight years,  with but got a little relief last year in the northern part thanks to help from  the giant Niño, one of the strongest ever.

Alas, it was one that failed to deliver as the big rain producer for the south half of Cal and the SW in general as was expected.

In case you’ve forgotten how bad things were in Cal, let us look back at what was being said, those horrific appearing drought maps,  and also how hopeful were were at the time  that the Big Niño would take a bit bite out of drought.  This is a really good article:

https://www.climate.gov/news-features/event-tracker/how-deep-precipitation-hole-california

Then, when the Big Niño faded away like maple syrup on a stack of buckwheat pancakes last spring and summer,  we were surely doomed for more dry years.  And, for a time, the dreaded cold tongue of water in the eastern equatorial region, the so-called, La Niña, started to develop, which would be no help at all for  a good rain season like a Big Niño is, usually.

The Niña faded away, too, to nothing as the winter went on, so we really didn’t have much going on in the tropical Pacific to help us figure out what kind of winter rainfall regime we were going to have om 2016-17.  Not having anything going on meant winter rainfall could go either way, a difficult to figure out situation for season forecasters.

In retrospect it is pretty astounding how big a signal must have been out there SOMEWHERE that this winter was going to be one for the history books on the West Coast in general, and in particular, for Californians.  Californians saw their drought chewed up and spit out in a single winter, including snow packs so high the height of some mountain peaks have been revised.  (I’m kidding.)

No one saw such an astounding winter coming.

This winter sure makes one think of the QBO (Quasi-biennenial Oscillation, one up there in the Stratosphere where there’s almost no air (haha, well, practically none)…  Did the QBO have a role in this astounding winter;  was there a delay in the effects of the Big Niño even without a bunch of convection in the eastern Pac tropics?  Doesn’t seem that could be right…

But, William “Bill” Lau, U of Maryland scientist,  reported some statistical evidence of  such a lag way back in ’88 due to a QBO connection of some kind and ENSO, no physical cause could be discerned, however,  not yet,  anyway.  Lau, 1988, is reprised below for readers who want to go deep:

Annual cycle, QBO, SO on global precip J Geophys Res 1988ocr

Sure has looked like the Big Niño WY we expected last year!

Some recent clouds; after all, this is CLOUD maven, not RAIN maven:

I’ve been kind of holding out on you.  I dropped my camera and busted it.  Its no fun taking pictures when you don’t have a real camera.  Still doesn’t work right, but take these anyway:

March 4th, afternoon. Hope you logged this; the rarely seen CIrrus castellanus (almost "congestus" in size) or, informally, "Cumulo-cirrus."
March 4th, afternoon. Hope you logged this; the rarely seen CIrrus castellanus (almost “congestus” in size) or, informally, “Cumulo-cirrus.”
Poppies are out, btw. Nice display on "Poppy Hils" just across and southwest of the Pima County Pistol Club, off Bowman.
Poppies are out, btw, in case you haven’t noticed. Nice display on “Poppy Hils” just across and southwest of the Pima County Pistol Club, off Bowman.
DSC_2499
March 4th, late afternoon. Nothing terrifically special in this tangle of Cirrus spissatus (“Cis spis” to cloud folk) but I thought it was just a really nice scene

Moving to the next day, Sunday, that REALLY windy day:

March 5, Sunday morning 6:13 AM. Altocumulus lenticularis alerts cloudwise folk to the possibility of windy conditions although it was already windy.
March 5, Sunday morning 6:13 AM. Altocumulus lenticularis alerts cloudwise folk to the possibility of windy conditions although it was already windy.
3:55 PM, March 5th. After a day of solid Altostratus overcast with underlying Cumulus and Stratocumulus, a layer of Altocumulus began to move in to add a little more interest to the sky.
3:55 PM, March 5th. After a day of solid Altostratus overcast with underlying Cumulus and Stratocumulus, a layer of Altocumulus began to move in to add a little more interest to the sky.
3:57 PM. Looking to the north revealed that some of the lower Cumulus/Stratocumulus complexes reached heights where ice could form. That smooth region on the bottom and right side of the cloud is a fall of ice from this cloud with a RW- (text for "light rainshower") if you like to text stuff) right below that. This is not a lot of ice and so you'd be thinking the cloud barely made that ice-forming temperature.
3:57 PM. Looking to the north revealed that some of the lower Cumulus/Stratocumulus complexes reached heights where ice could form. That smooth region on the bottom and right side of the cloud is a fall of ice from this cloud with a RW- (text for “light rainshower”) if you like to text stuff) right below that. This is not a lot of ice and so you’d be thinking the cloud barely made that ice-forming temperature.  CMP doesn’t think it was caused by an ice fallout from that higher layer, which sometimes can happen.  Let’s look at the most timely sounding, just to check.  From the real Cowboys at the University of Wyoming, this:
Ann 2017030600.72274.skewt.parc
The TUS sounding which I only now just saw, showing a vast separation between the lower Stratocumulus and the higher layers of Altocumlus and Altostratus on top. Note, too, that over TUS the tops of the lower cloud is not quite at -10°C the temperature we start to look for ice formation in AZ. However, our clouds were NW of that balloon sounding, and it would have been that tiny bit colder, and tops were also lifted some when they passed over the Tortolitas earlier, meaning that the tops of this complex were colder than -10° C (14° F) at some point.

Wow, too much information….after a hiatus in blogging I feel like that  Oroville Dam in California, metaphorically overflowing with too much hand-waving information.

6:03 PM, March 5. Its still real windy. Line of virga brought a few drops when it passed overhead at 6:30 PM.
6:03 PM, March 5. Its still real windy. Line of virga brought a few drops when it passed overhead at 6:30 PM.
6:04 PM. Nice dramatic shot toward Marana as the backside of the middle cloud layer approached allowing the sun to shine through.
6:04 PM. Nice dramatic shot toward Marana as the backside of the middle cloud layer approached allowing the sun to shine through.
6:09 PM. Virga getting closer. May have to park car outside to make sure I don't miss any drops!
6:09 PM. Virga getting closer. May have to park car outside to make sure I don’t miss any drops!
6:22 PM. SW-NE oriented virga strip about to pass overhead. Drops fell between 6:30 and 6:40 PM, but you had to be outside to notice, which you would have been as a proper CMJ eccentric.
6:22 PM. SW-NE oriented virga strip about to pass overhead. Drops fell between 6:30 and 6:40 PM, but you had to be outside to notice, which you would have been as a proper CMJ eccentric.  You would have WANTED that trace of rain report, maybe slackers would not have observed.
6:30 PM. Climax; the great sunset allowed by that backside clearing.
6:30 PM. Climax; the great sunset allowed by that backside clearing.

The End, at last!

Iridescence, jet streak Cirrus warn of overnight “middlin'” storm

I guess “billows” (“undulatus” in cloudspeak) two days ago in the late afternoon wasn’t enough of a sign that the weather was changing. Yesterday we had fast moving Cirrocumulus with rainbows in it, and as the sun was setting, “jet streak Cirrus”, a line of Cirrus clouds often seen in the very core of high altitude, powerful jet streams passed overhead.

How hard was the wind blowing up there in that Cirrus last evening? Oh, our Tuscon balloon sounding, lifting off around 3:30 PM, going up about a 1000 feet a minute to, indicates that the max wind up there at Cirrus level was 146 knots (just under 170 mph)! Yikes. Poor balloon.  Must be in France by now.

The storm has been a bit of a disappointment in rain production. We’ve only logged 0.22 inches1.  Not as much as foretold here, 0.33 inches, but that forecast was a better prediction than  by “Weather Underground Robotics” (0.58 inches).  Its great to beat a robot!

We had another sign yesterday in the fastest moving Cirrocumulus clouds I think you’ll ever see around here (about 100 mph), ones at just 18,000 feet above sea level, 15 kft above Catalina:   rainbows of color near the sun called iridescence (also called “irisation”).   Here, as is the norm here,  are a few too many shots of the same thing2.

DSC_1885

 

10:54 AM. The fist of weather is used as a prop to indicate that these colors are forming a ring around the sun.
10:54 AM. The fist of weather is used as a prop to indicate that these colors are forming a ring around the sun. Usually you try to find a light standard somewhere…maybe a “gopro cam on a stick” might do it. Just don’t look at the sun when you do this.
DSC_1894
10:57 AM.
DSC_1896
10:57 AM, pulling back some for perspective. As we often say here, “so pretty.” And look at how tiny the granulation is in this Cirrocumulus cloud is!

The colors themselves, of course,  don’t warn of something about to happen, but the fast movement from the southwest did; a powerful jet stream is over you.   That strong stream, the result of temperature gradients in the atmosphere, is dividing deep warm air from deep cold air, and steers the alternations of high and low pressure centers, and with those alternations of lows and highs along the jet stream, air is drawn from different latitude zones and the boundaries where those different masses of air meet at the surface, is called fronts.  Here, such as last night, its nearly always cold ones.

The rest of the day was pretty exciting, the wind arising suddenly yesterday morning, along with our usual great visibility, and darker blue wintertime skies, made the clouds stand out more.

7:56 AM. Looking to the west at a scattering of Stratocu patches.
7:56 AM. Looking to the west at a scattering of Stratocu patches.
7:57 AM. Highlight on the hills above Saddlebrook. Stratocumulus overhead.
7:57 AM. Highlight on the hills above Saddlebrook. Stratocumulus overhead.
8:42 AM. This patch of Stratocumulus was the result of a lift zone that often produces clouds headed our way in southwesterly flow. The difference here is how limited in size this patch was allowing you to see where that lift zone was. Downstream, though, descending motions creamed this cloud, one that sat there most of the early part of the day. Usually a whole layer is over us, with a clearing visible toward the SW horizon.
8:42 AM. This patch of Stratocumulus was the result of a lift zone that often produces clouds headed our way in southwesterly flow. The difference here is how limited in size this patch was allowing you to see where that lift zone was. Downstream, though, descending motions creamed this cloud, one that sat there most of the early part of the day. Usually a whole layer is over us, with a clearing visible toward the SW horizon.
11:02 AM. Still out there, still limited in size. Wind here now 20-30 mph with stronger puffs.
11:02 AM. Still out there pretty much near the same spot, still limited in size. Wind here now 20-30 mph with stronger puffs.

 

DSC_1904
11:40 AM. By this time it had shifted closer to us, still forming on the southwest end, dissipating at the downwind end where the cloud is so ragged due to mixing with dry, descending air.
12:42 PM. Creeping closer, but still a standing wave, dissipating as it came toward us.
12:42 PM. Creeping closer, but still a standing wave, dissipating as it came toward us.  It was about this time that it disappeared, the sky becoming more complex with no simple standing waves.

The sky at last, considering the power of the trough approaching, FINALLY began to fill in.  Started looking around for the first sign of ice having formed in these clouds as the air aloft became cooler. Along with this filling in by Cumulus and Stratocumulus clouds, some sun highlights began to appear on our mountains, contrasted by the darkening skies above.

1:55 PM. Stratocumulus banks up against the Catalinas, Samaniego Ridge.
1:55 PM. Stratocumulus clouds  bank up against the Catalinas, Samaniego Ridge.
2:03 PM. While Stratocumulus banked up against the mountains, huge temporary clearings occurred elsewhere. Notice how shredded the tops of these clouds are and how the tops lean to the right. They're revealing the great increase in the wind with height, and yet, how dry it was above this layer (that, by the ragged cloud tops mixing with the very dry air just above them.)
2:03 PM. While Stratocumulus banked up against the mountains, huge temporary clearings occurred elsewhere. Notice how shredded the tops of these clouds are and how the tops lean to the right. They’re revealing the great increase in the wind with height, and yet, how dry it was above this layer (that, by the ragged cloud tops mixing with the very dry air just above them.)
3:38 PM. Here comes the Jet Streak Cirrus! Also about this time, the frontal windshift line, marked by low scud clouds in the cold air, began to appear on the NW horizon. It was an exciting moment. Here we go! FROPA within a coupla hours maybe. Well, took longer than that....
3:38 PM. Here comes the Jet Streak Cirrus! Also about this time, the frontal windshift line, marked by low scud clouds in the cold air, began to appear on the NW horizon. It was an exciting moment. Here we go! FROPA within a coupla hours maybe. Well, took longer than that….
3:52 PM. A little ruffle of Cirrocumulus leads the advance of the jet streak Cirrus.
3:52 PM. A little ruffle of Cirrocumulus leads the advance of the jet streak Cirrus.
4:11 PM. Cloud line forming above the frontal windshift line. Was progressing this way at this time, but was to stall, maybe back off.
4:11 PM. Cloud line forming above the frontal windshift line. Was progressing this way at this time, but was to stall, maybe back off.
4:11 PM. Zooming, floating over Saddlebrooke, this close up of our FROPA and windshift line. Ended up backing off, dissipating, maybe reforming later after dark.
4:11 PM. Zooming, floating over Saddlebrooke, this close up of our FROPA and windshift line. Ended up backing off, dissipating, maybe reforming later after dark.  These lowest clouds form in the colder air associated with the windshift line at the nose of the front as the moist air ahead of the front  mixes with it and is lifted.  We see this with most of our incoming cold fronts, and in our summer thunderstorms.  The best cases  form “arcus clouds”, a solid line just above and behind the windshift at the ground.  These kinds of ragged clouds, in cloudspeak, are called “pannus.”  Was pretty excited here, as no doubt you were, that FROPA (frontal passage) was imminent, might happen within the hour.  Nope.
4:40 PM. In the meantime, our jet streak CIrrus moved overhead, the clearing behind this thin band leading to some memorable fading sun highlights on the Catalinas.
4:40 PM. In the meantime, our jet streak CIrrus, above the Stratocumulus clouds,  moved overhead, the clearing behind this thin band leading to some memorable fading sun highlights on the Catalinas.
5:40 PM. No words needed.
5:40 PM. No words needed.
5:43 PM. "Fading sun and rain gauge." Another one of those exceptional scenes you won't find anywhere except on this blog. Tell your friends. A small mammal, termed a "packrat" is decimating my prickly pear wind protection for this gauge! A lot of rain loss occurs due to wind. drops missing the collector! It very upsetting to see this happen.
5:43 PM. “Fading sun and rain gauge.” Another one of those exceptional scenes you won’t find anywhere except on this blog. Tell your friends. A small mammal, termed a “packrat” is decimating my prickly pear wind protection for this gauge! A lot of rain loss occurs due to wind. drops missing the collector! It very upsetting to see this happen.
5:43 PM. Even the often despised teddy bear cholla can be so beautiful in this fading sun, the spines capturing it so well.
5:43 PM. Even the often despised teddy bear cholla can be so beautiful in this fading sun, the spines capturing it so well.

Eventually our jet streak Cirrus provided the background for another great sunset scene:

5:56 PM.
5:56 PM.

 

 

A 300 millibar (about 30,000 feet above sea level) with an IR satellite image for yesterday at 5 PM AST. Arrows denoted the jet streak Cirrus cloud, enhanced in the downwind region of the Baja mountains.
A 300 millibar (about 30,000 feet above sea level) with an IR satellite image for yesterday at 5 PM AST.   The Cirrus layer extended from about this height to around 35, 000 feet above sea level.   according to our TUS balloon sounding.  Arrows denoted the jet streak Cirrus cloud thatpassed over us,  enhanced in the downwind region of the Baja mountains.  Note that the wind at San Diego max wind was even slightly stronger than our wind max was at this level at152 knots.  This map is the courtesy of the University of Washington Huskies Weather Department.

Today’s clouds and weather

From that map above, you’ll see that there’s a “tail-dragger” trough still to the west of us and about over Sandy Ego (haha). That’s going to keep the air over us extremely cold, and with some sun, the Cumulus clouds that arrive are expected to have tops colder than -15 to -20° C, plenty cold enough for the formation of ice.
Ice means precip, snow up there, rain down here in spots. So, we could still pick up a few more hundredths if a shower happens to drop by. The chance of isolated very light showers in the area is 100%, but no one can tell you if one will actually land on us. You’ll have to be watching, mostly after 12 noon. Look to the west toward the Tortolita Mountains, terrain that ought to spawn one or two of those.

Looks like a longer dry spell ahead; several days to a week, maybe more.

The End

—————————-

1CoCoRahs gauge, btw. NWS-style gauge had only 0.20 inches, likely due to enhanced wind loss associated with my collapsing prickly pear protector.
2 I was driving and had to park and jump out of car to get these.  You only have seconds or maybe a minute or three to capture stuff like this.

Strange sunset brew of clouds and color; but was it natural?

Cutting to the chase:  I don’t think so.

Yesterday,  after an ordinary beginning,,  finished in a spectacular, if likely artificial way.  Let us work our way through yesterday’s cloudulations:

DSC_9909
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.
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.
DSC_9914
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. 10:47 AM. It was nice to see low clouds topping Sam Ridge, the lower boundary layer air (where convection takes place) moist for a change.
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.
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.
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.
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) testicularis contrail. 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.
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.
5:13 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....
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. 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.
5:23 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.
5:25 PM. Thank you sun! Looks pretty round again, which is good.
DSC_9962
5:27 PM. Oh, so pretty.
5:27 PM.
5:27 PM. Zooming again. Wow.
5:28 PM. Another view of the same thing.
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.
5:28 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.
5:29 PM. Taking WAY too many photos of the same thing. Out of control… Here I demonstrate that with another photo of the same thing.

 

DSC_9984
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.
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:

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.
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.

In case you missed them…a 2008 full moon and, moving ahead, yesterday’s sunrise

The full moon of December 11, 2008. Thought maybe you'd like to see it again coming up over the Catalinas.
The full moon of December 11, 2008. Thought maybe you’d like to see it in case you missed it, or see it again if you did see it.  Maybe you had a special memory with this moon.
DSC_9864
7:09 AM. Altocumulus perlucidus with a little lenticular underneath.
7:43 AM.
7:10 AM. Zooming and zooming.
DSC_9869
7:10 AM. Zooming some more.
7:14 AM. Iridescence is evident in the cloud ripples just above the mountain silhouette.
7:14 AM. Iridescence is evident in the cloud ripples just above the mountain silhouette.
DSC_9884
7:16 AM, Contrails were soon visible in our Altocumulus layer, the aircraft making it at the right edge of the photo. Appeared to be in a climb out going right to left. And, when you see these “high temperature contrails” in Altocumulus, you can be sure ice will form and rifts will develop as a little bit of light snow develops and falls out.  The jillions of ice crystals in the contrail cause the droplets in the Altocumulus to evaporate, in a way, gutting it. An ice crystal is like a low pressure center when amid droplets;   the droplets evaporate and those water molecules deposit themselves on the ice crystal, a process named after the discoverers, Wegner-Bergeron-Findeisen.   Eventually the crystal is large enough to settle out and a clear streak results unless the air is rising rapidly and can replace the droplets (as generally happens in storms).  Sometimes the lift in the Altocumulus layer is enough that a clear canal caused by an aircraft can fill back in after many minutes.
7:18 AM. Two aircraft contrails, about a minute old.
7:18 AM. Two aircraft contrails, about a minute old.  After two or three more minutes, they will not be visible within the cloud, though ice is forming, decimating the droplets around the intense streamers of ice in the contrail.
DSC_9897
7:28 AM. The small ice canal (the ice is hanging just below the Altocumulus clouds–kind of hard to make out, but its there.
DSC_9900
7:42 AM. Those little clear streaks are hardly noticeable now, partly because they were quite narrow, and because of perspective and things bunching up in the distance.

 

From the Cowboys in Laramie, Wyoming, this TUS sounding for yesterday morning in the pre-dawn hours:

Suggested locations of cloud layers. The Altocumulus layer in which the contrails were embedded seems to be at -25°C, a "normal" temperature for this kind of "high temperature contrail". In general contrails are not supposed to occur until the temperature is below about -35° C and the air is moist, thus they are usually seen amid or near Cirrus clouds. not down in Altocumulus.
Suggested locations of cloud layers. The Altocumulus layer in which the contrails were embedded seems to be at -25°C, a “normal” temperature for this kind of “high temperature contrail”. In general contrails are not supposed to occur until the temperature is below about -35° C and the air is moist, thus they are usually seen amid or near Cirrus clouds. not down in Altocumulus.   See usual contrail height at Cirrus levels  in moon photo.

As the morning wore on, the Altocumulus deck faded away, moving east, and we were left with some Cirrus clouds, but what kind?

DSC_9904
10:58 AM. Cirrus of some type, but notice there is absolutely no fibrous details (strands and such) as we normally see in Cirrus.  Could be transverse waves in a Cirrostratus deck since Cirrostratus can be fog like, have no detail, in a version we call, Cirrostratus nebulosus.  The up and down motions would cause clearings perpendicular to the wind up there.  The lack of strands and uniformity in these bands suggests very tiny ice crystals, ones having very little fallspeeds.
DSC_9905
2:34 PM. Some nice “hovercraft” clouds, Altocumulus lenticularis off in the distance SSW. Hung around out there for a couple of hours.
DSC_9906
3:17 PM. This one appeared to be concave upward, which was a little odd. Zoomed view next.
DSC_9907
3:17 PM. Looks like the inside is higher than the outside. Huh.

Well, that was  it for photography yesterday.

Doesn’t seem to be any reliable indication of rain in sight.   Oh, sure, rain here pops up in the models almost every day, but its about 12-15 days out.  As the model gets closer to the day it predicted rain, it seems to go away like the “water mirage” on a hot paved road; always ahead of you, but you never get to it.  We’ve had some major rains indicated in the models as of a few days ago, but spaghetti was never very high on those events (clustering those crazy lines in a trough over us), so it wasn’t even worth mentioning.

And, even that rain is a gonner in the model runs from last night!

The End

A stragne and wonderful day

Many strange1  and wonderful sights were seen yesterday; I could feel the excitement out there as one cloud  microstructural mystery after another regaled our Catalina skies.

DSC_9657
7:24 AM. Here, a tiny highlighted flake of Altocumulus floating above a mass of light snow/ice crystals, maybe straight below it. This is one the classic mysteries we deal with in “cloud microstructure”;  the oddity of nature preferring to generate a droplet before an ice crystal at least to somewhere in the -30°s C. Liquid clouds often are at the top of Altostratus and Nimbostratus (rainy or snowy days) providing the tops aren’t too much colder than -30° C. How strange is it to have liquid water at the lowest temperatures in a cloud system, with all the ice and snow underneath, as shown in this photo (though here they are no longer connected).
7:24 AM/ I think there is itty bitty droplet cloud at the very top bright dot there.
7:24 AM/ I think there is itty bitty droplet cloud at the very top bright dot there.  A droplet cloud was likely much broader to have produced all the ice we see below that bright dot of liquid cloud.
DSC_9659
7:26 AM. Looking afar, to the SW, there’s what appears to be an Altocumulus (droplet cloud) with a few ice crystals underneat it, especially to the right.

How cold are these clouds?  Lets look at the TUS sounding, launched at about 3:30 AM yesterday morning.

The TUS rawinsonde balloon data for yesterday morning before dawn.
The TUS rawinsonde balloon data for yesterday morning before dawn.  That Altocumulus layer, and the other clouds above were likely at the pinched point above, topping out at -27°C and up around 23,000 feet above sea level (400 millibars), pretty darn cold.  But, as you saw in the 3rd photo, not a lot of ice is being generated at this temperature by that patch of Altocumulus clouds to the SW.  Not sure why, but its pretty remarkable and that is likely due to small droplet sizes AND a lack of ice nuclei, most of which are known to originate with soil particles  When you see these rare occurrences of all or mostly droplet clouds at low temperatures (<-20° C in particular, get ready to see hole punch and ice canals produced by aircraft, a kind of inadvertent cloud seeding.

That bank of Altocumulus was racing at more than 50 mph toward Catalina, and so it got here in a hurry.    And, as it got closer, it was also getting more into some airways at that height, possibly descents into PHX since the height of those clouds was below normal jet cruising levels at 23,000 feet Above Sea Level.

7:55 AM. This is one of the strangest sights I have ever seen. Why? On the left side of this photo, the clouds are completely glaciated, composed of ice, while along a line to the right, there's no sign of ice in Altocumulus clouds that appear to be at the same height (namely, temperature). I have no explanation for this scene, except those involving a lot hand-waving, so we'll just let go.
7:55 AM. This is one of the strangest sights I have ever seen. Why? On the left side of this photo, the clouds are completely glaciated, composed of ice, while along a line to the right, there’s no sign of ice in Altocumulus clouds that appear to be at the same height (namely, temperature). I have no explanation for this scene, except those involving a lot hand-waving, so we’ll just let go, except that we speculate that the Ac layer was a little lower (warmer)?  Could have been.

Now for the aircraft effects.  Hardly a few minutes go by before aircraft began marking up this cold Altocumulus layer.  Notice that it doesn’t seem to be producing much or any ice on its own, making aircraft inadvertent seeding lines and holes where tremendous numbers of ice crystals are generated immediately present.   Here’s the first of many:

8:16 AM. An icy canal due to the passage of an aircraft rips through this pristine layer of Altocumulus whose temperature was around -25° C.
8:16 AM. An icy canal due to the passage of an aircraft rips through this pristine layer of Altocumulus whose temperature was around -25° C.  The view is looking S toward Tucson, but is unlikely to have been an aircraft landing there because this layer was above 20,000 feet Above Sea Level.  An aircraft lanidng at TUS would be much lower, this close.  The passage of the aircraft was likely 10 or more minutes before this photo.
8:19 AM. The ice canal is broadening due to turbulence, and ice is not plainly evident to all Cloud Maven Juniors or we will have to go over discerning ice from droplet clouds at the next club meeting.
8:19 AM. The ice canal is broadening due to turbulence, and ice is not plainly evident to all Cloud Maven Juniors or we will have to go over discerning ice from droplet clouds at the next club meeting.
8:20 AM. A view of the northwest end of this aircraft-produced ice canal. Several others became apparent, too.
8:20 AM. A view of the northwest end of this aircraft-produced ice canal. Several others became apparent, too.

Heading for Catalina, this:

9:11 AM. Heading for Catalina, a whole mess of aircraft induced ice in that poor Altocumulus layer. The hole punch was likely due to an aircraft climbing out of or descending into TUS. The age of a hole that large, with ice below it like this would be something of the order of at least half an hour to an hour old. Just behind the hole is a new contrail in the Ac clouds,
9:11 AM. Heading for Catalina, a whole mess of aircraft induced ice in that poor Altocumulus layer. The hole punch was likely due to an aircraft climbing out of or descending into TUS. The age of a hole that large, with ice below it like this would be something of the order of at least half an hour to an hour old. Just behind the hole is a new contrail in the Ac clouds,
9:23 AM. Hole punch area and ice canal arrive over Catalina! Losing control here, taking photo and photo, now looking for stragne optics, usually observed with aircraft produced ice particles because they are so numerous, compete for the available moisture and therefore remain tiny and perfect, prisms, plates, short column ice crystals, ones that can do a lot of optical stuff.
9:23 AM. Hole punch area and ice canal arrive over Catalina! Losing control here, taking photo and photo, now looking for stragne optics, usually observed with aircraft produced ice particles because they are so numerous, compete for the available moisture and therefore remain tiny and perfect, prisms, plates, short column ice crystals, ones that can do a lot of optical stuff.

Here’s the south end of that ice canal:

9:24 AM.
9:24 AM.  Also note iconic horse wind vane, and real wind vane atop a personal weather station.  Doesn’t everyone have a “PWS”?

Looking straight up at the icy heart of a hole punch region caused by an aircraft.  I am sure you have never done this before!  This is gonna be a great blog with all these new things for you!

9:27 AM. Look at the detail in the ice, those fine, fine strands! Amazing. The thickest strand might be due to the higher liquiid water in the heart of one of those little Altocumulus cloudlets. ???
9:27 AM. Look at the detail in the ice, those fine, fine strands! Amazing. The thickest strand might be due to the higher liquiid water in the heart of one of those little Altocumulus cloudlets. ???  Look how much wind shear there is, those little itty bitty ice crystals falling so far behind the parent cloud, the streamers flattening out because the poor little guys, already undersized to begin with, are getting smaller and smaller, the fall velocity getting less and less until the strands are almost horizontal.
9:27 AM. Looking at this gorgeously uniform layer of Altocumulus perlucidus 9honeycomb of elements) translucidus (no shadows).
9:27 AM. Looking at this gorgeously uniform layer of Altocumulus perlucidus 9honeycomb of elements) translucidus (no shadows).  To me this is a phenomenal scene, though maybe to u, not so much, which is understandable.
9:30 AM. The expected intense optical phenomena began to occur in these aircraft contrail remains.
9:30 AM. The expected intense optical phenomena began to occur in these aircraft contrail remains.  Here a parhelia, or sundog.  More fireworks in a bit.
9:30 AM. While the parhelia was in its full display, very intense, this was the ice canal passing overhead. Look at the regular spacing of these strands of ice, Might be due to the spacing of the cloudlets in the Altocumulus layer, the spaces between them not producing much ice, or, as we know, contrails tend to clump behind the aircraft likely due to wingtip vortices interacting and combining masses of exhaust water and crud.
9:30 AM. While the parhelia was in its full display, very intense, this was the ice canal passing overhead. Look at the regular spacing of these strands of ice, Might be due to the spacing of the cloudlets in the Altocumulus layer, the spaces between them not producing much ice, or, as we know, contrails tend to clump behind the aircraft likely due to wingtip vortices interacting and combining masses of exhaust water and crud.   This is now about an hour and fifteen minutes old, since we saw it way out to the west at 8:16 AM shortly after it formed.
9:37 AM. Here's what a new aircraft contrail in these clouds looks like, this one about 60 s old looks like
9:37 AM. Here’s what a new aircraft contrail in these clouds looks like, this one about 60 s old looks like.  Note all the irregularity in the contrail from the get-go.

As the south end of the original ice canal began to enter the refraction zone for simple ice crystals around the sun, usually at the 22° degree halo position, things began to light up with a particularly bright circumzenithal arc (more often observed on a halo) or colorful (in this case) partial  “reverse halo”.   The colors (iridescence)  due to the refracting of light within very small ice crystals.   Normally iridescence is seen near the sun in Cirrocumulus clouds or the then edges of other droplet clouds.   Very exciting.

9:44 AM. Halo curving in the wrong direction, away from the sun!
9:44 AM. A part of a halo curving in the wrong direction, away from the sun! (This is actually called a circumzenithal arc).
9:44 AM. Taking up you up thousands and thousands of feet via a zoomed view.
9:44 AM. Taking up you up thousands and thousands of feet via a zoomed view.   Pretty cool, eh?  Notice how much its moved in just seconds,  You really have to let your coffee get cold if you’re a photographer and you want to get the best shots of this kind of phenomenon.  You really can’t do anything but keep watching every second!
9:44 AM, again. All these changes took place within the minute between 9:44 and 9:45 AM!
9:44 AM, again. All these changes took place within the minute between 9:44 and 9:45 AM!  Here, the next grouping of ice strands is being lit up.
9:48 AM. Just a pretty scene. Altocumulus perlucidus translucidus, pocked with aircraft contrails, if you look real close.
9:48 AM. Just a pretty scene. Altocumulus perlucidus translucidus, pocked with aircraft contrails, if you look real close.  Make me move:  $1 billion dollars…
9:54 AM. Its not even 10 AM and now this comes along, this fabulously complex zone of CIrrocumulus (at the same level of the Ac clouds) at the tail of the Altocumulus. You can see the much higher Cirrus going crossways, lower center. See TUS sounding for height of Ci.
9:54 AM. Its not even 10 AM and now this comes along, this fabulously complex zone of CIrrocumulus (at the same level of the Ac clouds) at the tail of the Altocumulus. You can see the much higher Cirrus going crossways, lower center. See TUS sounding for height of Ci.

Then this strange sight:

12:29 PM. A row of Altocumulus or Cirrocumulus, each formed by a little upward bump in the atmosphere of a layer just a hair below saturation. Just rising a few hundred feet or so causes these cloudlets to form. Why aren't they everywhere? Might be drier. Bumps like this are always present in the atmosphere, especially if there are mountains upwind.
12:29 PM. A row of Altocumulus or Cirrocumulus, each formed by a little upward bump in the atmosphere of a layer just a hair below saturation. Just rising a few hundred feet or so causes these cloudlets to form. Why aren’t they everywhere? Might be drier. Bumps like this are always present in the atmosphere, especially if there are mountains upwind.  Not taken while driving, of course, ; just looks like it thanks to photoshop.

The day closed out with a lower layer of Altocumulus moving in, this layer, according to the TUS sounding, at “only’ -17° C, and little ice detected.  Below, at 2:09 PM:

2:09 PM. Altocumulus perlucidus translucidus. A natural conversion to ice is occurring on the right side of the photo.
2:09 PM. Altocumulus perlucidus translucidus. A natural conversion to ice is occurring on the right side of the photo.
DSC_9836
4:42 PM. So pretty these Altocu.

 

4:41 PM. A strand of finely patterned Cirrocumulus shot out of the SW as the sun declined.
4:41 PM. A strand of finely patterned Cirrocumulus shot out of the SW as the sun declined.
The Tucson afternoon rawinsonde . launched around 3:30 PM.
The Tucson afternoon rawinsonde . launched around 3:30 PM.  The Cirrocu in the above photo was likely also at the Cirrus level indicated above.

U of AZ mod thinks so light rain will develop around here in the mid-later afternoon.

The End

—————————————–

1“stragne” above, originally an inadvertent typo, but left in place as another cheap trick to get draw the curiosity of readers who might wonder what stragne is.

A day with rare and regular clouds

Yesterday, whilst disappointingly dry, no rain fell here overnight was a day of rare cloud sightings, most of it involving the rarely seen, “Cumulo-cirrus1“, a cloud fakery situation where extremely cold (less that -40°Ç, -40° F)and clouds at Cirrus levels appear to be ordinary little Cumulus fractus clouds. I hope you weren’t fooled by those impersonators. You’d be pretty embarrassed at the next meeting when we go over yesterday…  Yesterday was, in essence, a test for you, and I hope you passed.

Along with the rare “Cumulo-cirrus” sightings, there were intricate patterns in Cirrocumulus clouds that may have caught you’re eye. However, with the wind aloft being so strong (around 90-100 mph at 18,000 feet) you didn’t have a lot of time to enjoy them.

Yesterday’s clouds

DSC_9554
10:01 AM.  These were the first “Cumulus” pretenders I saw yesterday, though I suppose the discerning eye might have called them “Altocumulus” as well.   When they first formed they look hard and rounded like they might have had cloud droplets.  But then within seconds, that brighter look caused by high concentrations of droplets or tiny ice crystals (sometimes called “germs” because they have no particular shape when just formed) fades as the concentrations decline rapidly due to evaporation and mixing with the dry environmental air around them.   Eventually, they become transparent.  Also notice that you don’t see trails come down out of them.  This is likely because the concentrations are so high that competition for moisture keeps all of the ice crystals so small they can’t really fall out.
10:01 AM. Zooming in.
10:01 AM. Zooming in.  The brighter ones have just formed.  The faded ones are the older ones heading for extinction.  Many more shots of “Cumulo-cirrus” to follow.  Got kind of carried away, as usual.
DSC_9557
10:18 AM. Another moist layer shot in, first showing up as Cirrocumulus, though this cloud was in the middle levels, not at Cirrus heights. The fine granulation makes it look higher than it really is. This was probably around 12, 000 feet above the ground, if that. One giveaway was the rapid movement of the cloud itself, and compared to the cirriform clouds above it. If they are near the same levels, they won’t move much at all relative to one another. Anyway, these patterns changed by the SECOND! It was amazing how quickly they devolved into something completely different.
DSC_9562
10:27 AM. A wid angle view of another incoming group of “Cumulo-cirrus.” The thinnest clouds are the ghostly remains of those clouds. The more compact and brighter ones are the youngest ones.
DSC_9565
10:27 AM. A closeup of a just formed globule. Everything around it was onece like that but now has the visual attributes of regular Cirrus.
DSC_9571
10:42 AM. One of the strangest cloud sights ever seen by yours truly, CMP. Here a layer of Cirrocumulus (note fine patterns lower center) passes rapidly underneath those globules of fake Cumulus clouds full of ice.

Explanatory figure below:

Ann DSC_9571

DSC_9597
11:22 AM.  Another patch of fake Cumulus fractus at Cirrus levels comes by.  Note the true Cirrus in the background, and was higher than the fake Cu fra.
DSC_9601
11:36 AM. Was beside myself seeing this! Just incredible!
DSC_9604
11:38 AM. Just two minutes later! Look what has happened to that puff ball of ice. The turbulence up there must have been tremendous.
DSC_9621
11:57 AM. Some real fakery here. Ordinary people would have said, “Oh, those are just little Cumulus fractus over our Catalinas.” But not you. You would have chided them in friendly, gentle way, telling them they were WAY too high for Cumulus clouds and are mainly composed of ice, not possible for low Cumulus fractus clouds.   You could have also pointed out that the cloud in the upper part of this photos were way below those Cumulus fakeries, and that they about to obscure them as this encroaching  layer slid underneath them.  Also, try not to be condescending, act superior like you know so much even though you do.  You might lose your friend if you do that.
11:53 AM. Another zoomed view of one of those icy puff balls, not long after it formed.
11:53 AM. Another zoomed view of one of those icy puff balls, not long after it formed.
DSC_9635
4:01 PM. Altocumulus opacus underneath a Cirrostratus layer. A great sunset was in the works with that opening to the southwest. Also notice, no ice or virga evident. Guess that the temperature at the tops of this layer, likely only a couple of hundred meters thick, is warmer than -10° C.
DSC_9647
5:31 PM. Altocumulus opacus at sunset. The height of this layer was about 8,000 feet above Catalina by the TUS sounding, top temperature about -5° C. “No virga, no cry,” as Bob Marley said.

The End

—————
1Though it fits, I made this cloud name up.  Probably would be Cirrus floccus, maybe Cirrus castellanus in the humped up cases.

Colorful evening ends day with a colorful morning; a note on the great Cal rains of October 2016

Not much else to talk about, no rain of course;  what is that?

But with so many colorful scenes yesterday, we can be partially sated by the  lives we lead here sans rain here.  October ended with a puny 0.01 inches in Sutherland Heights.

Now, because I grew up in California and remain a little Cal-centric, this brief diversion from AZ:

But droughty Cal got nailed though, from about San Luis Obispo, so we can be happy about that I guess.  One station, Gasquet RS,  near the Duck border,  got just under 28 inches in October; stations in the Santa Cruz Mountains, way down by Monterrey, got between 14-17 inches!  From the California-Nevada River Forecast Center, this nice map of October rainfall anomalies in that domain.  Red is real dry, and that’s the color we would be in if it was the California-Nevada-Arizona River Forecast Center:

Many departures are far over the map color-coding limit of 350%, but are over 1000% of average!
Many departures are far over the map color-coding limit of 350%, but are over 1000% of average!  Note red below normal swath.  This tells you that the mean area of low pressure at the surface and aloft was just off the West Coast.  Pac NW set maximum October rainfall records, too.

But let us not dwell any more of generous rains that others got, but celebrate the color and clouds of Arizona.   Here are yesterday’s glorious scenes, beginning with a spectacular Altocumulus lenticularis under some Cirrus at dawn:

DSC_9019
6:37 AM.
DSC_9022
6:47 AM. Ac len stack.
DSC_9027
10:51 AM. Tiny patch of Cirrocumulus tried to hide in front of some Cirrus. Hope you weren’t fooled and logged this sighting in your cloud diary. Cloud maven person almost missed it himself.
DSC_9030
12:50 PM. There were lenticulars aplenty yesterday. Here’s another one in a location a little different from normal, beyond the Catalinas. Upwind edge is the smoothest one at right. No ice streamers coming out the downwind end, so must have been pretty “warm”. Lenticulars, due to their tiny droplets and those droplets having short life times, have been known to resist ice formation to temperatures well below -30°C -22° F). Pretty amazing.
DSC_9034
2:42 PM. Kind of clouded up in the afternoon, and with breezes, made it seem like something was up. It was, but far to the NW of us. We have been under a streamer of high to middle clouds originating deep in the Tropics for a couple of days. Here some lower level moisture has crept in on cat’s feet, to be poetic for a second, and has resulted in small Cumulus and Stratocumulus clouds underneath the Cirrus and lenticulars standing around. All in all, though the temperature here reached 87° F, a very pleasant day.

Now, just some nice lighting and color:

DSC_9045
5:32 PM. The almost flourescent plant in the foreground is what is known as a “cholla.” The end elements fall off quite easily and attach to things like your pant leg if you brush by them on a horse, or if back into them while walking and correcting your horse for something when he’s acting a little “wild.”  I can report that when seven or eight of them are stuck to the back of your shirt, its really hard to get that shirt off.  In fact, it just about won’t come off without a major scream.
DSC_9047
5:35 PM. The higher Cirrus are shaded by clouds to the west, but the lower remnants of Stratocumulus/Cumulus and a few Altocumulus are highlighted as though they were meant to be for this photo. So pretty.  Notice, too, how there seems to be more than one layer of Cirrus.
DSC_9053
5:44 PM. Cirrus and Altocumulus, the latter with some turreting making those the species, “castellanus”, if you care.
DSC_9059
5:47 PM. A nice flame-out of Cirrus occurred as those pesky clouds blocking the fading sunlight from striking them opened up below the horizon. A few Altocumulus castellanus can be seen, too, but relegated to shadow status.

In a further celebration of dryness here, let us examine the rainfall cumulative rainfall predictions calculated by the University of Arizona’s Dept Hydro and Atmos Sci computer the period ending at Midnight on November 5th.  Says the coming rain in the State misses us here in SE AZ while falling just about everywhere else, of course.  Dang.  Let’s hope it one of the worst model predictions ever!

This really poor forecast is based on the global data from last evening at 5 PM AST.
This really poor forecast is based on the global data from last evening at 5 PM AST.

 

The End.