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:

DSC_3231

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.
3:36 PM. Letting the font size demonstrate the excitement I was feeling, that excitement filling the whole sky! Maybe the temperature in this inadvertent experiment would be stupefyingly low, like -40 C (-40 F), in which case I might get a publication of my photos. Another great aspect was that this canal was streaking toward me (us)! It just could not have been a better situation.  And I would add, in retirement mind you, to my CV and I don’t even have a grant!  It was going to be a great day!
3:40 PM.  See photo.
3:40 PM. See photo.
3:47 PM.  Normal contrail in ice cloud continues to evolve as ice canal gets closer.
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.
DSC_3282
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.
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.science laughs_005

Now about those pretty patterns, by Simon and Garfunkel.  Enjoy.
1:08 PM.
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1:13 PM.
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1:34 PM.
1:34 PM.  Forgot this nice one…..

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.