Cirrus altocumulus castellano-floccogenitus

We had a rare form of Cirrus yesterday, whose name I have made up in the title as a hint of where they came from, due to the very high altitude and low temperatures of some Altocumulus yesterday.   Those Ac morphed to Cirrus, hence the strange, unpronounceable  title.

Reminder,  weatherscience mavens, its more proper to say “low” temperatures; not “COLD” temperatures, FYI, though you constantly hear it.  (“Things”, like coffee, air, chairs in the sun, etc., are hot, warm, cool,  tepid, and cold; temperature is not a physical thing, and is high. moderate, or low, etc.))

Still bristling over some unexpected clouds yesterday, so I wanted to complain about something minor, bring some discipline to the field.

Mr. Cloud-maven person was not paying attention, asleep at the wheel, etc., when some Altocumulus castellanus and Cirrus castellanus came a truckin’ over the horizon and floated over Catalina after dawn yesterday, but had not been mentioned in this blog in advance.   I am sure, since they had not mentioned  from this keyboard, you may have been in some distress yesterday when they showed up and you weren’t sure what was happening.  My apologies.  It will almost never happen again.

Here are some photos of the interesting clouds that passed overhead yesterday.  I was quite excited to see them partly because I had not prepared myself mentally for them.  Now, there is something strange in the first caption.   But I wrote it that way on purpose because I REALLY want to know if YOU know WHERE the HELL you are, and where the mountains are around here.  Next, after that outrage,  some interesting banded Cirrus. Then a hint at where those Cirrus came from in the background of the 3rd shot.

First, this sunrise over the Tortolita Mountains with Cirrostratus nebulosus (vellum-like cloud) and a hint of Cirrocumulus (tiny, brighter, flocculent specs).
This banded Cirrus gave some hint as to its origin. Might be termed, Cirrus uncinus, or floccus, or fibratus, its a pretty complicated set.

 

Caption function not working now for this third shot in WP, so here it is:
3) A nice example of Cirrus uncinus in the foreground, tufted or hooked ice clouds trailing tiny ice crystals.  In the background, a clue to the origin of the patchy, banded Cirrus.
4) Another shot of the approaching Altocumulus castellanus (Ac cas) and (Ac floc) floccus clouds as they arrived overhead, some of which have morphed completely into ice (Cirrus) clouds, such as that larger element over the house in the foreground!  In the upper left quadrant of this shot are Ac clouds that, to this eyeball, are still liquid.
Droplet clouds have more sharply defined edges because droplet clouds have MUCH higher concentrations of particles in them than ice crystal clouds (which tend to make them “fuzzy”, ghost-like, striated, fibrous, etc.
Why this visual difference, which I want you to learn, to see for yourself and impress your friends?
There are more cloud droplet condensation nuclei than there are ice crystal nuclei.   For example, liquid Altocumulus clouds might have 100,000 to 500,ooo drops per liter in them, while ice crystal clouds may have only tens to a few thousand per liter  (and then only in newly formed elements) of ice crystals.  In general, there are more cloud condensation nuclei than ice nuclei, too.

Today

While “Joe” is spinning up into his little hurricane-like self in some kind of weather tantrum off the California coast today before heading to Oregon, our skies over Catalina will be marked by various forms of Cirrus clouds, ice clouds well above 25,000 feet above the ground, and not much else.  BTW, you can follow Joe’s progress here from the U of WA, if interested.

If you’re interested, instead, of following our Cirrus clouds as they approach and go overhead today, go here, also from the U of WA.  You see the Cirrus clouds pealing off the main frontal band in the Pac NW and then fading as they head this way.  (I would increase the speed of the loop for maxium excitement.)

The End.

 

Author: Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.