Category Archives: Bullet rosettes

Hihg clouds begin to move toward Catalina! Storm of bullet rosettes ahead!

Misspelling the word, “high” was inadvertent; but leaving it was deliberate, thinking it might work as another cheap attempt to get more than one reader1, presently my mom.   Hi, mom.  Glad you enjoyed your mom’s day dinner yesterday, followed by the exciting trip through the Catalina car wash.  Really squirts, doesn’t it?

Continuing….people might wonder if “hihg” a new word or acronym they haven’t seen before, maybe wonder if it describes something they should know about.   So, I am looking to capture one or two extra folks today.

Our next “storm” will occur mostly above 20 kft above Catalina in the form of light snow showers of single ice crystals from Cirrus clouds, typically those crystals that fall out of Cirrus clouds are bullet rosettes.

What’s a bullet rosette?  See below:

University of Washington flight engineer, Don Spurgeon monitors the Stratton Park Engineering Company's images of "bullet rosettes" in flight.
University of Washington flight engineer, Don Spurgeon.  monitors the Stratton Park Engineering Company’s images of “bullet rosettes” in flight.  Chad Slattery, Smithsonian mag free lance writer, took the shot.  Sadly, Don and the other crew members did not get into the Smithsonian article, only Pete Hobbs and me.  Pretty sad for them but happy for me! Yes, I was on this flight!  Except it wasn’t a flight, we were sitting on the ground at Paine Field, Everett, WA, where our plane was kept, and Don brought up that image so that Chad could take what would appear to be an “action. in-flight” shot in his article.


Oh, there could be an Altocumulus cloud, too, by tomorrow.  But that’s about it.  Our last storm was not actually a storm, btw, though there were some low clouds.   I guess it got pretty windy, but not rain fell here, nor did it snow whatsoever atop Ms. Lemmon, though it was cold enough to.  Boohoo.

But, the overall trend for upper cyclonic systems to nest over the Great Southwest continues, insuring a mild May here in Catalinaland, and also a ton of precip in other parts of the SW, with only brief interruptions of hot air, like the kind that comes from this weather keyboard.

The pretty, and high Cirrus clouds should begin arriving this afternoon, except that some are already arriving (5:20 AM)!  Cloud maven seems to be on a wrong streak!

Next Catalina rain chance, graciously presented by the Canadians, is overnight, May 14-15th, just a few days from now.  Check it out.  This graphic been arrowated and texted for your convenience and understanding.

Valid at 5 AM AST, May 15th.  Lower right panel shows where The Model thinks that rain has fallen during the prior 12 h, and it includes Catalina!
Valid at 5 AM AST, May 15th from the Enviro Can GEM model.   Lower right panel shows where The Model thinks that rain has fallen during the prior 12 h, and it includes Catalina!


The End



1Still can’t get over that Atlantic article about, “Blogging for dollars”; its like a song hook, maybe like the one from,   The Model,  by the very Germanic Kraftwerk techno-pop group, and yet after two years, I have made nothing!  With millions of readers, you can make a LOT of money, get some great advertising like the various stuff that precedes the viewing of The Model, which has already accumulated more than 4 million views!

So I continue to reach out for readers and money.

What would a neurotic-compulsive, self-described “cloud maven” do with “a LOT of money”?

Underground power lines in his neighborhood.  They obstruct sky and cloud views.  Used to be quite a movement around the US to do that, but not so much anymore.


7:35 PM.  Curtains of ice droop down from heavy patches of Cirrus spissatus (or you could call this Altostratus, too)
7:35 PM. Curtains of ice droop down from heavy patches of Cirrus spissatus producing an outstanding sunset last evening.  Hope you saw it.  What kind of ice?  Likely “bullet rosette” ice crystals are the ones falling out.
Bullet rosette as maged at 120 mph by an instrument on the University of Washington's research aircraft high over Barrow, AK, toward the bottom of Altostratus clouds around 23, 000 feet above sea level.
The complex ice crystal called a “bullet rosette” for some reason as imaged at 130 mph by an instrument (Cloud Particle Imager) on the University of Washington’s research aircraft high over Barrow, AK.  These were at the bottom of Altostratus (thick ice)  clouds around 23, 000 feet above sea level.  Tops were about 32,000 feet, and was thick enough to produce a gray overcast.  The CPI was designed and built by Paul Lawson, a friend who was a starting defensive back on the Michigan State Spartan’s National Champion fubbal team of 1966 or 1967.  He formed,  and is still the CEO,  of Stratton Park Engineering Company, one that makes a lot of high end instrumentation for imaging cloud particles.  Likes to meditate, too;  just kind of sits there for hours on end like a piece of pottery.  I don’t get it.  Maybe its related to concussions he might have gotten.


Action shot of the University of Washington Convair-580 research aircraft, in case you wanted to see that.
Action shot of the University of Washington Convair-580 research aircraft in flight, in case you wanted to see that.  My job was to stand on a little stool (hmmmm, that doesn’t sound right) so my head would be high enough and fit in that little dome and say things about clouds, which as here, was usually too much.  Pretty cool, eh?
















Wasting time here, filling in with filler material1 since there’s no real chance of rain, though, as usual, pretty clouds and maybe some real nice sunrises llike this morning’s and sunsets.  That’s OK.  We’ll get by until the Big Boys arrive, those Cumulonimbus clouds of summer, with all their splendor and drama.  As reported in the media, a better than average rain season is being foretold by the Climate Prediction Center.  How nice is that?

Small Cu today, maybe a CB top way off toward the S or SE….  Have some nice Altocu now, splattered around. No rain in WRF-GFS hereabouts for two weeks, but, as we know over and over again, they can be VERY wrong in that longer view!

The End.


1Remember when newspapers had “fillers”, interesting little facts punctuating the pages where the columns and such left little spaces after being laid out? They had some fascinating material in them, such as that a certain spider’s web strand, if the diameter of a garden hose, could support TWO 747 jets!  (True!)

Sequence in C; Cirrus spissatus

Some nice CIrrus spissatus and the rare Cirrus castellanus yesterday (something I say a lot here in old AZy).   Here is half hour sequence of a patch of heavily precipitating Cirrus spissatus,  kind of a cloud oxymoron.  I thought it was pretty spectacular even if you don’t care one wit about it.  (Hahaha,  “wit” instead of “whit.”)

Those Cirrus clouds were up at about 35,000 feet above sea level, at around -50 C (-58 F), but snowing like mad.   Don’t let folks tell you its too cold to snow; usually happens that way because here on the surface there’s a high pressure over you, the sky is clear, to wit; a fair weather pattern, and that’s why its not snowing here on the earth when its -58 F, except maybe when there’s a ice haze called “diamond dust“, tiny ice crystals floating/glinting in the air.)


8:48 AM. Cirrus spissatus on the left with the little snowstorm trailing off to the left will pass overhead of Basha’s parking lot there on Oracle in about half an hour, a prediction made in hindsight.
9:07 AM

9:07 AM.  Taken while not driving down Equestrian Trail Road to Basha’s supermarket.
9:21 AM.  Basha's parking lot.
9:21 AM. Basha’s parking lot.  Snow, composed of single crystals, not flakes or what we called “aggregates” because they don’t stick together at such low temperatures, pours out of this really cold cloud.  The single crystals in the trail would be bullet rosettes, a complex looking crystal consisting of hexagonal columns that stick out from a center point. How much snow falls out?  Just a dusting.  You could blow it away off any surface.  When flying through these icy clouds toward the top where the crystals are simpler, there are sparkles and glints when the sun hits the crystals just right.  Very pretty.


The day ended up with lower Cirrus and few Altocumulus clouds with virga as the dry air aloft moved in, providing the clear western horizon that allowed the sun to highlight our clouds.  That great sunset, as much as I could see anyway being “on the road” here:

5:37 PM.  Heavy Cirrus with Altocumulus on the right.
5:37 PM. Heavy Cirrus (spissatus) or Altostratus patch, either name OK, with Altocumulus on the far right horizon.

The weather ahead

Mods still showing rain in the area on Sunday the 17th pretty consistently now. And as we saw from the “errorful” NOAA spaghetti maps yesterday, a trough with cooler weather, clouds and scattered precip is pretty much in the bag for that time period (16th-18th). Can only hope that we get something measurable here. But, even without rain, those days will be pretty ones with Cumulus clouds around.

“Los Angeles” Catalina

Got a little homesick yesterday looking at the white sky, the barely visible mountains in the distance, like Twin Peaks, eyes a little teary, not from sadness so much, but from smog and smoke.  Grew up in the San Fernando Valley you know, Reseda.  Lots of smog there at times, though not as much as in Burbank, thank heavens, where it banked up against the San Gabriel Mountains.

Reseda, as you know is quite famous from the Karate Kid movie and was even mentioned by Frank Zappa in his Tinsel Town Rebellion album so I like to tell people that I grew up there, went to Reseda High School, played some sports. Maybe I should add a sports highlight to convince you that I went to such a famous high school, and maybe, too, mention that overpowering, incapacitating crush I had on Rozzi R. when I was 15 years old, since a story like that would titillate your interests more than a sports story, or maybe even stuff about weather.  I think I know the people who read this blog pretty darn well.

Below is that “nostalgic” LA sky we had yesterday, thanks to fires in New Mexico, the second one of the yellowish-orange sun typically associated with smoke particles.  Of course, the “white sky” is common on humid days back East, and in the global warming domain, is our friend.

Yes, that’s right, smog is our “friend”, because, as was likely yesterday, in spite of record heat, the temperature would have even been a tad HIGHER without that smoke layer!

In fact, one of the conundrums in foretelling climate in the coming decades, is how much smoke, our “friend”, will offset the warming due to trace gases like CO2.  Imagine, a world of never-blue-but-always-white skies and no more worries about global warming!

As the cliché goes, “Beam me up, Scotty” if such a world came to pass!  So, lets knock off the fires, all smog, in fact, and untoward gases!

  More clouds, less smog today 

In case you missed it, some sunrise Cirrus today!  Finally a cloud.  Who cares if its at 45,000 feet above the ground!  It shows there can still be humidity in the air.

Probably had some….OK, your guess… on the ice crystal type up there in those Cirrus clouds.

Yes, that’s right, bullet rosettes, would be an excellent guess, crystals with a solid “germ” center from which columns radiate outward like these ones below captured in Cirrus clouds over Barrow, AK, some years ago.


 Update on “dusty coolsnap”, foretold many days ago for around June 5th.

 Here, from the NWS Tucson, you will see that “dusty coolsnap”,  foretold by the models many days ago, has been evolving into “breezynotashotsnap”, if you can call that a “snap”, a word that implies more suddeness that what will likely happen.  Still, a trough brushes by to the north, just doesn’t have the amplitude it once did in the models; we’ll see only some moderation in temps.  How can they not “moderate” after record highs, so that was an easy thing for me to say.

Still no rain in mods for hereabouts, but some close calls from afternoon thunderstorms in New Mexico every now and then.

The awful indications is, just beyond a week from now, more record HIGH temperatures lasting for a few days!  Yikes.

The End


Snow day February 25th; “webby” Cirrus

Remember, whether it happens or not, you heard about it FIRST here!  Tell your friends.

Was pretty excited to see this 500 millibar map (about 15,000 to 20,000 feet above sea level) for the morning of February 25th below from our friends at IPS Meteostar.  Pretty cool, eh?  This from the model run based on global data taken at 5 PM AST yesterday.

Note on that map, we are encircled by the jet stream, indicated by the brownish orange regions at the outskirts of this behemoth of a trough, a requirement for winter precip here.  How “be-a- moth-ian” is it?

Check out how abnormal this pattern is in the panel below this one, marked by the dark blue bulls-eye here in Arizona!  So, its really an unusual pattern that is being calculated by the computer.

An aside:  Oddly, we use contours of the height above the ground of a pressure surface for our upper level maps1, and the LOWER that height is (such as over AZ in the top panel), the COLDER the air must be overall below that height.  Low sea level pressure also adds to this height “deficit”, but mainly its the density of the cold air that does it.  The more dense the air is, the more rapidly you reach above you any particular pressure level.  (It really would be so much better to have pressure maps with highs and lows at a constant level above us than having to divert attention for this explanation.)

So, in the panel below, its the LOW HEIGHT of at which the 500 millibar pressure was reached (i. e., 5340 meters) that tells you this is a cold, cold, cold, cold system.  (They say that redundancy is the key to remembering things.  Remember, “534” (decameters) is COLD).

What DOES that the huge anomaly from normal in the bottom panel tell us weatherfolk?

The forecast map for February 25th is a real outlier model forecast, and so we shouldn’t be proclaiming a snow day or anything like that here 15 days in advance because it is such an extreme prediction and likely to go wrong.  So, that’s what I have not done here.

HOWEVER, this outlier prediction shown below, is a part of a jet stream pattern that is developing RIGHT NOW in which low pressure systems and cold fronts will come zooming down into the Southwest from the northwest, one that is likely to go on for  a couple of weeks or more.  I would guess there might well be a hard freeze at some point, though not in the immediate future.  Be ready!

This developing pattern also means more chances for rain here in Catalina over the next few weeks, and with the cool air ahead, holding our late winter vegetation together better even if there is not much precip because it won’t get burned out.  So, overall, good news unless you came to AZ for consistently warm days.  Ain’t gonna happen so enjoy the warmth we have now!

 Webby Cirrus clouds

Yesterday, moving rapidly out of the north, were some “webby” looking Cirrus clouds.  These are always seen only right after they have formed, maybe 10-20 minutes or so after that.   They start out as tiny flecks (which for a moment might be termed, Cirrocumulus clouds), and, possibly, for the briefest moment, may be comprised of liquid.  They then convert to ice and as the individual crystals grow and fall out,  or are dispersed by turbulence,  the tiny flecks become larger and larger and some of the ice falls out in strands.

After about a half an hour to an hour, they are usually just masses of tangled looking Cirrus without much cellular structure.  Here’s what they looked like yesterday in that younger formative stage.  At most upwind end (lower part of photo), the newest flecks have formed, while the older Cirrus elements are broadening and becoming “webby” looking.  The likely ice crystals in these older Cirrus, for some additional annoying trivia, “bullet rosettes”, spikey-looking crystals having columns jutting out from the original “germ” ice particle.  Nice images of bullet rosettes here at the beginning of a long article…






















1In the olden days, weatherfolk liked to look at “isentropic surfaces” which helped them figure out where the air was sliding upward and likely to form clouds and precipitation before there were computer models. These areas were well represented on constant pressure maps where the cold and warm air was being pushed around.