All posts by Art Rangno

Drizzle and Stratocumulus bonanza

No, this is not about Bonanza, the TEEVEE show, “Hoss”, or any of those ranching people, though that might be more interesting than a blog about clouds, gray ones.  First of all, the word, “bonanza” would be capitalized (its not on my view of this edit, FYI)  if this was a blog about it.  Second, there was no “Bonanza” episode about Stratocumulus and drizzle, another clue.

Your cloud diary, for those of you still reading this blog:

8:34 AM. An orographic layer of Stratocumulus tops Sam Ridge while a separate higher layer covering the whole sky sits on top of it. Neither one seem to be able to produce precip, ice or “warm rain”–precip without ice.
8:34 AM. Stratocumulus. Light rain is falling from them on the horizon. What does it mean? Those clouds over there are just that bit thicker, tops higher and colder. Could be a warm rain (no ice involved) or a case of “ice multiplication”, a still continuing mystery in the cloud and precip domain where more ice forms in clouds than we can explain. Mostly occurs when the cloud top temperatures are higher than -14°C to about -4°C. Ice crystals can be in tremendous concentrations in such clouds but we don’t know quite why yet. So, models that forecast rain and snow, as good as they are today, could be that bit better if they could accurately the ice in clouds in that cloud top temperature range I just mentioned a few paragraphs ago. That’s probably the biggest payoff for really understanding how ice forms in clouds. At the University of Washington, me and Peter Hobbs were reporting that the consensus theory on how ice formed in clouds was not capable of explaining what we were finding in the clouds we sampled with our aircraft. There was too much ice in clouds, and it appeared too fast. We were on the outside looking in and our whole body of work was criticized as being wrong by two of the great professors of ice-formation in clouds, Alan Blyth and John Latham in 1998. They used our names in the title of the article, too, “the glaciation papers of Hobbs and Rangno.”  I sent a copy to mom.  This is what happens when you’re not part of a consensus, you eventually get criticized royally because no one believes you, they think without commenting about it that your work is bogus. At the same time, it was truly GREAT that Blyth and Latham took time to look into all of our work since we scientists don’t do enough of that kind of thing, look into the work of others we suspect might be wrong. But over the years, the concensus about how ice forms in clouds has weakened and new factors are being touted as important players like drizzle drops that fragment or explode when they freeze because at certain temperatures an ice shell develops on the outside of a freezing drop, and then when the water farther in freezes and tries to get out because it wants to expand, it breaks the ice shell, and maybe spicule or ice splinter comes out helping to produce extra ice we call secondary ice particles since they didn’t form on an “ice nuclei”, something we have a though time measuring anyway. Fragmenting drops as they freeze has been known about for decades, but now its being thought that maybe a lot fragments result, not just a few as was thought before.  So those extra ice crystals end up creating concentrations of  ice crystals  we can’t quite explain in clouds here even in 2018,  such as those ones over there that were raining north of Saddlebrooke to bring us full round in this photo.  Caption too long?  Let us not forget that this site originated the practice of novella-sized captions.  I think many of you forget that a picture is worth a thousand words of caption, too.  Here, we’ve only managed a few hundred.
10:13 AM. Still raining way over there NE of Saddlebrooke and Bio2 if you look carefully, lower right. Can there be a better “classic” photo of Stratocumulus? I don’t think so. Cloud bases still running about the level of Sam Ridge, or about 3,500 to 4,000 feet above the ground.
10:05 AM, maybe. Stratocumulus clouds spewing drizzle precip roared out of the west in a band, now enveloping the Catalinas toward Pusch Ridge. Drizzle is pretty rare in Arizona, so I hope you noted it in your diaries yesterday. Means the clouds overhead have low droplet concentrations, and the larger drops are greater than about 30 microns in diameter, which are those sizes that when they bump together they can coalesce into a much larger drop that collides with more and more drops to form ones that can fall out of the cloud instead of just hanging around up there not doing much. We call that process the “collision-coalesce” process of rain formation, or “warm rain” process, one that doesn’t involve ice. The formation of ice almost never results in drizzle, hence (is that still a word?), why CMP thinks it was a warm-rain process yesterday over there. Also, drizzle is often think enough to make it look like its a snow shaft, which is what we see over there, too. But we know the freezing level was really high yesterday, so it can’t be snow over there. Nor are the clouds Cumulonimbus ones that CAN produce dense shafts.

Well, let’s move ahead to sunnier conditions, those pretty scenes we see on the mountains when a storm begins to clear out.

12:27 PM. As the Stratocumulus broke up, you got a glimpse of the deeper clouds north of Oracle that had been, and likely were still raining. Estimating depth here at about 2 km, or 6600 feet. With bases at 4,000 feet above ground, that would put the tops at only around 11,000 feet, too warm for ice since it would barely be below freezing at that height. Will check now to see if that statement is true.  Actually, the soundings from the U of AZ make it a little more ambiguous than what I was thinking about too warm for ice formation, and so there’s no point in showing those soundings where people might question what you just said.
1:19 PM. So pretty. I am a lucky man to see scenes like this so often.
1:29 PM. A cloud street with this fat boy formed off the Tortolita Mountains and it passed overhead of Catalina! I wondered if some big drops might fall out since it would be a Cumulus congestus if you could see it from the side, and with “warm rain” having fallen earlier, there was still a chance that the drops in this guy, toward the tops, would reach sizes where they coalesced into drops.
1:29 PM. Nice. One of our photo niches is cloud bases, and here’s one of the best. Am waiting outside for big drops, not Godot. Can’t go inside because they might only fall for a few seconds or minutes, it surely won’t be shaft.  And what if no rain had fallen earlier?  I might need to report a trace.
1:41 PM. It wasn’t too much longer the drops began to fall, finally thinking to get a photo in case no one believed me that rain had fallen from that cloud.
2:11 PM. Cumulus humilis and Cu fractus are all that remain of the gray skies of morning.
3:59 PM. Just enjoy.
6:37 PM. The sun, completing its weary journey around the earth, finally goes down.


The End

PS:  The agonizing delay from typing then seeing words appear 5-10 s after you stopped typing, disappeared when I jettisoned Firefox for Safari.  So, all these months of agony, were due to a Firefox bug, not a WordPress or GoDaddy hosting service problem.  Unbelievable.  This problem I think began when I downloaded the latest version of Firefox, which also came loaded with pop up ads and web site diversions it previously was free of.  Dummy me never connected it to the venerable Firefox web browser.   So, Firefox has been trashed from this computer!

50 actual shades of gray

Huh,  Sounds familiar.  Well, 50 shades of gray is a theme here at  Those various shades brought 0.02 inches of rain this morning to The Heights.  Here are yesterday’s 50 shades:

7:58 AM. Massive ice cloud advances on Catalina from the Tropics.

This Altostratus invasion covered the sky within about 15 minutes, and that was it for sun, except some “filtered sun” at times (when this layer is called Altostratus translucidus (the sun’s position can be seen).  Its an all ice or mostly ice cloud.

10:58 AM. Altostratus creates a pleasant gray sky.
1:26 PM. Lower droplet clouds began to appear, high-based Stratocumulus. The globules are too large to be Altocumulus, though these were based at about 7,000 feet above Catalina, or a little above the height of Ms. Lemmon.
1:26 PM. A UFO appears to be soaring toward Catalina with some kind with a trailing spider web.  Other lenticular can be seen, this one was truly out of this world.  But, from where?  What world?
1:41 PM. More lenticulars; more shades of gray.
3:36 PM. Altostratus is now transitioning to Nimbostratus with lower bases as steady, but very light rain, moves in toward Twin Peaks.  What you’re looking at here is mostly virga, and, as the relative humidity increases below virga bases, the virga is able to drop to lower elevations.  The humidity is increasing due to gradually rising air that is accompanying an upper level trough. Got pretty wind about this time, too, before calming down.  Not sure what that was from except maybe virga falling into very dry air ahead of the rain.
3:42 PM. Classic look of Altostratus translucidus. “Opacus” (too thick to see the sun), just ahead. Those darkest areas near the sun are droplet clouds.  Most of the scene is ice cloud.
4:16 PM. Finally, as very light rain began to fall, we now see the most perfect view of Nimbostratus you’ll ever see. I hope you took plenty of shots of this scene cloud maven juniors!
(Nimbostratus, the deep, deep cloud producing steady rain and snow is almost ALWAYS partly or totally obscured by lower Stratocumulus clouds so you can’t really see it. But, not here!

The weather ahead

Pretty much a sure-thing rain (we, unprofessionally forecast at least a 90-100% chance of measurable rain then) will move in late on the 16th or on the 17th.  Should be a significant, vegetation-boosting rain, too–by that I mean at least a quarter of an inch–unlike this rain this morning.  It looks,. too,  like a second rain might  move in a day or two after that one.  Quite strong support in the ensembles (“spaghetti plots”) for that to happen, too.  How great would that be?  Very great, of course.

After that, the models are showing even more troughs affecting AZ, but the ensembles aren’t sure about it.  Neither am I (CMP).

The End

More March rain ahead; and not so far ahead

High cold ones that are headed this way in a curvilinear path. Image was made at 5 AM AST, annotation later.

That means that a deep Altostratus overcast will be in place by tomorrow with a load of virga and sprinkles, not really much rain since the bases will also be cold and…high.  Top possible rain amount from these high cold ones is a tenth of an inch, but more likely will be traces.  Chance of a trace in the area?  Oh, about 99% IMO.

But that’s not our full rain destiny.

On the horizon, only a week from now, is the likelihood of a significant rain.  Check the models and the spaghetti:

Valid at 5 PM AST, March 16th. You don’t need the precip prediction for this day when the 500 millibar pattern is like this, the core of the wind at that level south of Tucson. Its not a sufficient criterion for rain, but a necessary one in the cool half of the year. (Only about 5% of the rain in TUS falls outside of this criterion in the cool half of the year.

Here’s the rain prediction which I have not looked at until posting now to make the point you don’t need to look at it:

Where the model thinks it will have rained in the 6 h prior to 5PM AST on March 16th. I hope you’re happy now.
Valid at 5 PM AST March 16th. Blueish lines of cold and rain (546 decameter geopotential height contours) way down the Cal coast, and somewhat bunched (confidence indicator) for a major trough to affect all of Arizona, keep the current greening underway.

Would say the chances of measurable rain from this “incoming” are at least 90%; i. e.,  virtually certain.  (Note that “virtually certain” is not the same as 100% certain,  but its damn close.)

Problems with hoster and connections to hoster continue–must wait seconds to see what I’ve typed, then have to go back and correct the gibberish.  So, not doing much as a result.

But here are a couple of cloud shots from yesterday anyway:

6:17 PM. Altocumulus perlucidus appearing to spread out, though likely a perspective tomfoolery. Thin Cirrostratus above.
6:39 PM.

Addendum:  Coupla of days ago saw the rare “Cumulo-cirrus” clouds, ones that appear to be Cumulus but are fakes, up at Cirrus-levels.  You might call them Cirrus castellanus.  I feel these are worth sharing so that the young cloud maven person doesn’t embarrass himself or herself when making a cloud call to friends and neighbors, as you would do.  They occurred on March 7th between 11:30 AM and Noon.  Can you tell, upon “zooming big” that these are mostly ice clouds?  If droplets were present they were there for only a short time, thus (is that still a word?) indicating that these rag clouds were at very low temperatures.

Some sounding detective work below

The 5AM AST sounding for March 7th. The sliver of moist air at 16,000 feet above sea level is not deemed the source of those rag clouds.
5 PM AST, March 7th sounding with writing on it.


The End

The Greening

Its not a  review of a new Stephen King movie where people turn green after eating too many vegetables.  Its a status report on growing grass as of yesterday from a hike.

Got pretty excited yesterday watching grass grow.  Below, some exciting examples of growing grass, mostly from the flats around the Canada del Oro wash near the Catalina State Park entry building,  in case you’re thinking about rushing down yourself to see grass grow. Some areas are not so far along (last photo).

Nice to see this eruption of green after our 2 inches or so of rain recently.  Even saw a couple of poppies popping up by the entrance to the Park.

More rain in route, as you know.  You can see it spread in from Cal here in this model depiction from the U of Arizona Wildcats weather department.  It arrives Tuesday overnight.  Amounts appear to be rather modest at this time–around a quarter of an inch.

Chance of measurable rain here in Catalina?   100% (IMO).

While these photos popped in in a rather timely manner after changing ISPs, typing text remains an unsolved buggabo; must wait several seconds to see what’s been typed, making any writing, such as it is, a real debilitating slog.  Thanks for sharing my pain.

The weather way ahead

Doesn’t look so great for more rain after this upcoming event.  The ensembles (spaghetti plots) show the trough bowl we are in now retrograding to offshore of the West Coast.  This will be great for droughty California, but downstream over the SW will be a ridge leading to a long dry and warm spell as this regime change takes place after our rain.

The End






Morning smog attack

One branch of a seemingly bifurcated plume, spread north along the side of Samaniego Ridge.  The other branch appeared to moved out of Tucson to Continental Ranch, “thence” northward toward the east side of the Tortolita Mountains.  It’s happened before, but is pretty rare, maybe once a year occurrence.

(Took an hour for these first three jpegs to be uploaded to WP, btw.)

7:23 AM.
7:25 AM.
7:25 AM.
8:16 AM. Smog plume at its maximum northward extend along Samaniego Ridge, Sutherland Heights area, before dissipating.
7:49 AM.
8:58 AM. Stratocumulus perlucidus races toward Catalina.
7:59 AM. Altocumulus translucidus perlucidus undulatus, quite a cloud-filled mouthful.
5:30 PM. This rain shaft is strong enough that one could suspect a weak Cumulonimbus cloud has erupted from the Stratocumulus.

Quitting here due to slower than dial-up service, hosting service, “godaddy” has confirmed its not them….





Cloud advisory

Have cameras ready for interesting clouds today as yet more storms approach.  Winds at 500 mb (around 18,000 feet above sea level) are forecast to approach 100 kts by tonight (oops, TOMORROW NIGHT!  Egad).  With winds like that, likely will be some nice lenticulars around to add to your collection.  Oh, I already see one downstream of the Catalinas….

Maybe some photos later if  the upload problem can be resolved.

Its not resolved….  But, trying to look at the bright side, while this ONE photo was uploading, I got some more coffee, read a book (Cadillac Desert, Marc Reisner, and got a good start on, Mythical Rivers by Melissa Sevigny–both highly recommended for cloud maven readers.

6:27 PM AST last evening, though after the brutally slow uploading speed to WP, maybe its not the same day as I started this upload anymore….

Some more on the upcoming rain and wind event in the next 24-36 h:

From this keyboard, 10% chance of less than a trace (pitiful forecast), in other words,  a zero from this storm, and 10% chance of more than 0.40 inches.  The average of those two, which helps center a forecast in the forecaster’s mind, great or small, would be, say, 0.21 inches.

But the wind max during this storm event will be the most  “interesting” part of it:  10% chance of puffs less than 35 mph, 10% chance of more than 65 mph , in this forecaster’s opinion.  The average of those would lead me to think that very momentary gusts will reach 50 mph (averaging those extremes to center a forecast).  So, the wind in the next 24-36 h is really the most interesting thing to keep an eye on; stuff will blow around, shingle fragments likely to come off.  This is NOT a NWS forecast.

The End

1“Puffs”: almost instantaneous blasts of a few seconds.

Rain train keeps on chuggin’ over Catalina

Toot, toot, drip, drip.  Rain fell on Catalina, Arizona, for the third day in a row, bringing our three day total, at least in Sutherland Heights, Catalina, to 2.18 inches, and over NINE inches at Ms. Mt. Lemmon, subject to quality control later.

Here’s a nice map, courtesy of the Pima County ALERT network, whom I haven’t actually asked to post this but you can go here and see it in the original:

The three day totals for the Valentine’s Day starting storm of February 14th, of course, through the 17th, 4 AM to 4 AM AST. The map has been enhanced with a total over that time period from Sutherland Heights for comparison.

Yesterday’s clouds

No photos, still suffering from WP or godaddy hosting chokehold.  Even text takes seconds to appear!  Worse than dial up.  The above jpeg, just 1.4 mb, took several minutes to upload!

The weather way ahead and soap-boxing the erroneous,  “warm temperatures” expression

While the NOAA ensembles let us (me) down in mid-January when it appeared that troughs would dominate in late January through early Feb (it wasn’t even close to that interpretation, and the first time I’ve seen those crazy plots do so badly, will go with them now and present a couple that strongly suggest the drought pattern has been decimated for Arizona and the Southwest; no more weeks of no rain or rain threats, with ridiculously warm days (note, not days with “warm temperatures”,  a temperature is a unit of measurement, not a thing that can be cold or warm—-got it?  Its the AIR that’s warm or cold, or a day, a month.  What if, when a high pressure sat on Arizona,  that I said we had really “dense millibars today”, to make a comparison showing how WRONG it is to say, “warm temperatures.”  Its HIGH temperatures or LOW temperatures, etc.    Tell your friends….

OK, will go through that bit more of uploading misery with these stupefying spaghetti factory plots.  Inspect them and be happy if you like unsettled weather, storms threatening or actually occurring every few days.  The first one is a week from nows, then ten days from now, and the last one two weeks from now.  Exult over the troughulent regime we’re now in!  Yay!

Note how the red and blue lines dip southward over the whole southwest US. That dip represents the location where upper air troughs will be occurring at this time. The red lines are more or less the periphery of the jet stream on the warm or tropical side, and the blue lines nearer the heart and cold side of the jet stream.

This “ensemble” approach, where tiny errors are deliberately input into the model data as the computer run begins is deemed one of the great advances in forecasting, this due to more powerful computers that can crunch so much global data so fast.  There are always errors in the data, and we can’t measure the atmosphere over the whole globe in an instant, and this is a way of determing what the errors might do to the forecast.  Heck, we don’t even know what the real errors are.  So we input some and see what happens.

The greater the effect errors have, the more spread out and chaotic the patterns are.  When the red and blue lines stay close together, it indicates that at least, tiny errors, don’t have much effect.  Normally, after ten to 15 days, the lines are kind of a mess, with only general patterns discernible.  (Sure is annoying typing and waiting seconds to see what it is you’ve typed!)

In last evening’s global data runs, the red lines in our domain stay pretty bunched up, indicating a strong indication of troughing over these next two weeks, even out to 15 days!  So, cloud maven person is pretty excited thinking that maybe a wildflower or two can now pop up, and our spring greening will go forth.

Just yesterday on a dog walk to the Sutherland Wash,  tiny plants were bursting forth from the ground.   What a miracle that is.  (The wash had no water in it.)

The happy ending

Rain drenches Catalina! Mt Lemmon passes four inches!

Sutherland Heights total as of 5:34 AM (tipping bucket): 0.90 inches!  No way was this much expected from this keyboard.  Looks like the rain is going to continue for a few more hours, too.  Just terrific!  Update:  1.21 inches in CoCoRahs gauge at 7 AM!

As of 4:34 AM, these totals from the Pima County ALERT gauge rolling archive :

Catalina Area        
0.87  Golder Ranch (Horseshoe Bend Rd in Saddlebrooke)
1.26  Oracle Ranger Stn approximately 0.5 mi SW of Oracle 
0.94  Dodge Tank, Edwin Rd 1.3 mi E of Lago Del Oro Parkway               1.34  Cherry Spring, approximately 1.5 mi W of Charouleau Gap 
1.38  Pig Spring, approximately 1.1 mi NE of Charouleau Gap
0.94  Cargodera Canyon, NE corner of Catalina State Park 
0.79  CDO @ Rancho Solano, Cañada Del Oro Wash NE of Saddlebrooke
0.71  CDO @ Golder Rd, Cañada Del Oro Wash at Golder Ranch Rd

Santa Catalina Mountains
1.42 Oracle Ridge, Oracle Ridge, approximately 1.5 mi N of Rice Peak
4.06 Mt. Lemmon, Mount Lemmon
1.42 CDO @ Coronado Camp, Cañada Del Oro Wash 0.3 mi S of Coronado 
1.02 Samaniego Peak, Samaniego Peak on Samaniego Ridge  (looks low)
3.03 Dan Saddle, Dan Saddle on Oracle Ridge
2.20 White Tail, Catalina Hwy 0.8 mi W of Palisade Ranger Station
0.83 Green Mountain, Green Mountain
1.97 Marshall Gulch, Sabino Creek 0.6 mi SSE of Marshall Gulch

Let us look noew at the precursor clouds from yesterday:

Sorry, no images.  It took more than 2 h to upload several images yesterday, and now, as also has happened since downloading the latest version of WP, several seconds before I see what’ve typed!

This has been going on for weeks and weeks, ending the fun in  blogging.

Will be spending the next few weeks either moving to another hosting site, blogspot, or figuring out why WP has become unusable (again).

The End.

Behold! Cirrus!

We often have phony dramatizations suggested by titles with exclamation marks, and frankly, today is no exception.   I do like Cirrus, though.  Hope you do, too.

Why like Cirrus1?

They provide a lot of nice sunrises and sunsets.  EOM.

Example of a recent CIrrus sunset, FYI.
An example of a recent display of Cirrus at sunrise.


Yesterday’s displays of Cirrus, ending with a scruff of Cumulus toward Pusch Ridge:

7:29 AM. Cirrus castellanus, or what we sometimes call, “Altocumulocirrus” because it looks so much like just Altocu.

Rain’s on the doorstep!

The End