Cumulus and ice

Today:

Virga here and there, chance of sprinkles through early afternoon, then blammo, clearing as wind shift aloft makes it way across Oro Valley/Catalina.  CLouds will consist of Cumulus mediocris virgae, small Cumulonimbus capillatus virgae.  Cloud bases will be below freezing and higher than Ms. Mt. Lemmon, so will be tough to get rain down to the lower elevations, though a virga trail may hit The Lemmon.  Tops of Cu, -15 C to -25 C, i.e., cold enough for ice formation, of course.  Crystals will be mostly stellars and dendrites with some clustering into aggregates we would normally call “snowflakes.”  Some of the very coldest tops will contain some solid columns, maybe some prisms and hexagonal plates.

If you’re having trouble here because you’ve forgotten a few things, you might well want to get your Magono and Lee (1996) ice crystal “bible” and review crystals types and the temperatures they form at.  Heck, maybe I’ll just put the first couple pages here for you…Magono and Lee (1966).  Everybody had one back then.  Very important to have that with you.  As a further challenge, I have not rotated two pages to the upright position to make it too easy for you.

I suppose, too, that you COULD hire an small aircraft to go up there and check on these predicted types using the old “black glove” technique of the early 1960s, where a scientist would stick out a black-gloved hand from the passenger side of the aircraft and then report/log the ice crystals he found.  Not making this up.

 Yesterday’s clouds (something’s “wrong”)

Day started out dusty; ended up dusty.

8:16 AM. Dirt roads 'n' dust, that's who we are. Got some Altocumulus, but they are so high and cold (-30 C) that they transformed into patches of Cirrus clouds almost immediately. Pretty normal, even at temperatures that low for a liquid drop to form first, followed by freezing. Weird.
8:16 AM. Dirt roads ‘n’ dust;  that’s who we are. Got some Altocumulus, but they are so high and cold (-30 C) that they transformed into patches of Cirrus (ice) clouds almost immediately. Pretty normal, even at temperatures that low, for a liquid drop to form first, followed by freezing. Weird.

 

8:23 AM. Here, a real bird, not a fake one, begins to notice something extraordinary; the virga trails from the parent cloud are going the "wrong way", toward the northeast!
8:23 AM. Here, a real bird, not a fake one, begins to notice something extraordinary; the virga trails from the parent cloud are going the “wrong way”, toward the northeast!
8:35 AM. "What's going on here?", the photo asks. Well, the virga trail is going FASTER and leading the head or "generating cell" from which it issued, meaning the wind increases with velocity going down, not UP, as usual! Incredible, really! Hardly ever see this. Is it due to global warming, the polar vortex has maybe turned upside down? I think so.
8:35 AM. “What’s going on here?”, the photo asks. Well, the virga trail is going FASTER and leading the head or “generating cell” from which it issued, meaning the wind increases with velocity going down, not UP, as usual! Incredible, really! Hardly ever see this. Is it due to global warming/climate change, the polar vortex has maybe turned upside down? I think so.  Has annotations on it.

 

12:07 PM. Then I saw this, a cloud with no name, but could be the silhouette of a polar bear, eyes and head at lower left. Can't be Cu fractus, but a thermal has pushed a damp layer up here, causing a concave shape. You don't want to fly that small plane in or below this cloud, looking for ice. It would be real bumpy.
12:07 PM. Then I saw this, a cloud with no name above the Catalinas.  Could be the silhouette of a polar bear, eyes and head at lower left looking downard, asking what have we done to it? Its white, too.   Can’t be Cu fractus, though a thermal has pushed a damp layer up here, causing the concave shape.  You don’t want to fly that small plane in or below this cloud, looking for ice. It would be real bumpy.

DSC_0059Above, through the dust, for some perspective of our ghost  “bear.”  Pretty cool, huh?  I hope there are some left by the time I get done with this blog!  Maybe I should check….let’s see what the Canadians (well, one Canadian at U of Victoria) has to say about this dire sitiuation, get informed about stuff.  Here’s a link provided by the climate provocateur, and former WA State Climatologist, Mark Albright, who forwarded it to me for my own illumination.  I found that post interesting, unexpected…maybe you will, too.

12:39 PM. Iridescence in Cirrocumulus patch. Very pretty for a minute or two, then gone.
12:39 PM. Iridescence in Cirrocumulus patch. Very pretty for a minute or two, then gone.

 

 

3:24 PM. Day ended up cloudy and dusty with some areas looking like sprinkles could have fallen out and reached the ground, but nothing here, and echoes on radar were awful weak when present.
3:24 PM. Day ended up cloudy and dusty with some areas looking like sprinkles could have fallen out and reached the ground, but nothing here, and echoes on radar were awful weak when present.

 

Rain continues to show up on the forecast horizon, which is about 8 days

Best chance of rain, 21st-23rd, mods fuzzy on which day has the best chance.  If you love spaghetti, you’ll love this one below.  The vast change in the pattern, indicated for almost two weeks now, is just about here.  Some mod runs have rain as this “trough bowl” develops, and a strong trough passes through from the west.  Seems more likely than not from here that rain will fall as that happens.

Valid for 5 PM AST March 22nd.
Valid for 5 PM AST March 22nd.

The End. (Nice sunrise, lots of Ac cas, Sc, virga around!)

By 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.