All posts 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 I participated in were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.
Definitions

Catalina Water Year Rainfall Data Updated

5 Comments
The “ENs” denote those winters with significant El Niñoes. The biggest of all, back in 2015-16, didn’t do much as far as SW weather goes. Generally, as you can see, they are very powerful “weather actuators” for us.
Our poor summer rains kept this from being a truly spectacular water year. Still, over 20 inches is very good.
Our bountiful September rains kept this summer from resembling one of those from the early and mid-90s.
Definitions, Spaghetti plots, The weather WAY ahead (10 days or more)

Mid-month outlook: December 2018 to close out on a wet note (or notes)

3 Comments

Mr. Cloud Maven person doesn’t have to tell you, the advanced Cloud Maven Juniors,  where he gets such an outrageously distant forecast that most meteorologists are afraid to make; it originates with clustered lines on  something we call the “ensembles”, plots representing the greatest advance in computing and weather forecasting since the Intel 486 chip could be had at 386 prices.   In case you don’t believe me again…..

Right out of Computer Shopper magazine, too! You can’t find deals like this today, that’s for sure.

Here’s what I am talkin’ ’bout, the “ensembles” or fondly, “spaghetti plots” for 5 PM AST, the 27th of December, two weeks from now:

The red lines are about where the middle and southern edges of the core of the jet stream is, so, its going to be way south of us, “way” being at least a few hundred miles in its average position by then. That means RAIN here! “Whey” is something else, we don’t what; you should make that clear if you’re pronouncing this exact forecast to someone.

We ignore immediate weather and the possibility of rain on the 16th and again on the 18th ; the TV men and women of weather always have that well-covered.

Looks to be shaping up to be a very good spring wildflower season I’d say.  Tell your friends.

The End, except for some recent cloud photos:

From a few days ago, little fluff-fluff cloud on Samaniego Ridge.

Be thankful we live in Catalina. Here the TUS urban plume exits TUS borne  on SE winds toward Continental Ranch and points W and N. Rarely affects Catalina. Sometimes this urban plume is referred to as the Mark Albright smog plume, named after a well-known U of WA meteorologist who accidentally bought a house over there.

December 11th. A band of Cirrus spissatus with almost regular virga trails graced the evening sky.

Finally, also from December 11th, this beauty:

Altocumulus castellanus with heavy virga trails. As a cloud maven, you would estimate cloud top temperatures are less than -20°C, and probably closer to -30°C.

 

Definitions

November to close out/December to begin on wet notes

Kind of tired off entering zeroes for precipitation every day in CoCoRahs and the U of AZ’s rain log. org, as you are, too.

So, what the HECK, am going to end the boredom to assert that November will close out,  and December will begin with storms and significant  rain here in Catalinaland.   Our November average rainfall is just under an inch, less than October or December’s normal.  Hence, if anyone uses that word anymore, its not unusual for a dry November, as this one has been so far., completely so.

This outlandish, even outlaw forecast is based on many “signs”; the ensembles  (aka, spaghetti plots) are trending toward a stagnant trough along the West Coast with the jet flow way down into Baja California with the southern edge of the jet stream clustering around Cabo1 (!),  combined (ingredient 2) with computer models that now and then show strong storms invading southern California and the interior of the SW recently (again showing strong storms in the latest model runs,  combined (ingredient 3) with the rapidly developing Niño conditions in the central and eastern Pacific2 , combined (ingredient 4) with a strong gut feeling that the usual fantasy storms being predicted in the model for us beyond 10 days from now are real–well, they ARE real in the model, just not generally in real life.

I think they’re real this time.  End of story.

Here are some of the usual plots to feast your eyes on, if anyone is out there, after the long hiatus here.  While its not likely that a particular upper level configuration will verify exactly as  shown below, a map for two weeks from now showing a colossal trough affecting the SW, it does nevertheless appear as though similarly strong troughs will be affecting AZ as the month closes continuing into early December.

Before those major troughs threaten appreciable rain, some weak upper air disturbances will bring lots of cirri form and middle clouds (Altocumulus and Altostratus) prior to the onset of the major troughs. One of those preceding  weaker ones might produce a sprinkle Monday night into Tuesday.

I hope you’re happy now.  As the Beatles once sang (before they sadly changed the lyrics to something about guns) ,   “Happiness… is a big rain, mama, yes it is….”

The End

1In case you don’t believe me, here’s a typical spaghetti plot from last evening’s global model run at 5 PM AST with directions on it:

Valid on Thursday, 5 PM, November 29th. Illustrative diagram showing stuff.

Valid December 1st, 11 AM AST. An example of a humongous storm that’s shown up on the computer models. A couple of storms for AZ precede this one. If this exactly verified, there’d be cloud bursts, hail. maybe a waterspout or two in southern Cal.

2In case you don’t believe me that there’s a significant Niño developing, here is a link to the Climate Prediction Center where you can read so that you can see that I am not lying about it:

CPC Niño discussion (80% chance of coming through)

Historically, the SW does great under Niño conditions except during that “Godzilla” Niño of a couple of years ago.  We’ll forget about that “Godzilla” bust in ’15-’16; it kind of materialized the following winter (’16-’17) when there was no warm water in the east Pac at all!   Yes, that’s right, Virginia, weather often breaks your heart,, but then surprises you with the unexpected to make you happy again.

But, not this time, I venture, will there be a “bust.”  In fact, I would buy some Niño merchandise right now, maybe a Tee, proclaiming in a big font,

“Niño 2018-19!  Oh, yeah,  baby.                                                                 Weather and water is on the way! ”

Maybe that’s too much, but, that’s what we’re about here, too much of almost everything, including footnotes.

Catalina climate data, Definitions

Looking back before the end (Catalina’s June-September rainfall)

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OK, its not the time of the end…of the month, but since no rain will occur before the end of the month, thought I would give you a heads up on our latest summer rain, now having 41 years of data (thanks to the early reports by Our Garden down off Columbus and Stallion, a great natural produce farm:

Pretty remarkable how consistent our summer rain has been over the past 22 years (since 1996).  Can’t continue forever, as we know. Notice, too, that our summer rain has increased slightly (red trend line) over 41 years.  Can’t really count on that continuing, either.

———–

Still pretty much in a blog hiatus, as I work on science stuff–“manuscripts” (reviews, histories, critiques)……to submit to actual peer-reviewed journals.  Best to have peer-review literature since almost everything else is ignored, even if its accurate and well-researched; it can’t really be cited in peer-reviewed pubs.

cloud-maven a

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2017-18 Water Year progress report for Sutherland Heights/Catalina :(

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“Read ’em and weep”, as a Los Angeles Times sports scoreboard page used to say:

So far, so bad.

No joy ahead in “Dustville”, as a once mighty trough has struck out.  An  long-foretold, incoming trough for April 8th appears now to not have enough amplitude (i.e., the core of the jet stream won’t get to us, but will stay a little to the north of us).  Only wind and a temperature drop is likely.

Should see some nice Cirrus from time to time though….maybe small Cu after the cold front passes.  Oh, me, living in a desert can be hard.

But, “hey”, the northern Cal drought is getting squashed quite a bit by major spring storms, with some monsters still ahead.  I guess we be happy for them as they recover from extreme drought.  Snowpack around Reno/Lake Tahoe, to give you an example,  has made its biggest recovery in some 41 years as of April 1st after the near record low on March 1st.  Reno is near northern California.  And, a whole lot of precip is in the pipeline.   Might even make the news….

The End

Definitions, Spaghetti plots, The weather WAY ahead (10 days or more)

Measurable rain to fall in April 2018! (In the Heights of Sutherland)

1 Comment

As readers know, we like to jump out ahead, sometimes exceeding professional standards:

“Right or wrong, you heard it here first!”

The totality of evidence, which isn’t all that strong is in our beloved spaghetti plots, ones that have misled us a coupla times this winter…

Valid at 5 PM AST April 8th. These outputs based on global data from last evening at 5 PM AST. Note how the cold blue lines dip into Arizona!  So, a big trough is guaranteed about on April 8th, maybe one with enough amplitude to produce a significant rain here in the Sutherland Heights.

 

The End.

Cumulus clouds, Definitions, Ice crystals, Virga

Frosty the Cumulus cloud

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No NWS sounding from the U of AZ Weather Department yesterday afternoon, so’s we can’t really tell with solid data what the temperatures of yesterday’s frosty clouds were.

However, with a max here in the Heights of Sutherland of 71°F, and with a dry adiabatic lapse rate to the bottoms of the clouds (as is always the case on sunny afternoons with Cu), if we estimate how high the bottoms were with any accuracy we can get that bottom temperature.

You already know as a well-developed cloud maven person that they were WELL below freezing which could see by noticing how far the snow virga extended below the bases of the Cumulus, at least 3,000 feet.  and more from the larger clouds later on.   So we have something,

Let’s say bases were at 14,000 feet above the ground over Catalinaland–they were way above Ms. Mt. Lemmon at 9,000 feet which you could probably tell.  That would make the bases at about 16,000 to 17,000 feet above sea level in the free air, pretty darn high above us.

From a ground level of 3,000 feet, and with the dry adiabatic lapse rate of 5.4°F per 1000 feet, that would make the cloud bottoms a cold, cold, -2°F, or about -17° to -18°C!  COLD!  Then, tops, of  clouds only 3,000 feet thick (about 1 km), would be -28° to -30°C (assuming a mix of the dry adiabatic rate with the “moist adiabatic” rate, given yesterday’s conditions, or about 4° per 1000 feet, “plus or minus.”

Addendum–corrections, hope nobody see’s ’em:

Later analysis and the next morning’s NWS sounding from the U of AZ suggests that bases were closer to -10°C because they were not as high as CMP estimated.  Rather they were closer to 12,000 feet ASL.  Tops would not be quite as cold, too, more like -25° C and colder in the deeper clouds, plenty cold enough for ice in even the small clouds, and for the long snow virga trails.

Below, some samples of Frosty the Cumulus (Cumuli, plural):

1:22 PM. Small Cumulus (humilis and fractus) begin to form.

 

3:40 PM. By mid-afternoon, the slightly fatter Cumulus clouds (mediocris) start showing ice crystals coming out the downwind side, which is what that bit of haze is above the cloud outline.

3:41 PM. An ice haze is seen here, too, in the dissipating remnant of a humilis-sized Cu on the left edge, center.

4:10 PM.  Ice is appearing just about everywhere now as the air aloft cools a little more, and the Cumulus deepen upward some.  The clouds are likely no deeper than about 3,000 feet or about 1 km.  Tops, using the in-cloud lapse rate, typically a little less than the dry adiabatic rate, would be a frigid -27° C (-17°F) or so, which readily explains the ice-behaving nature of yesterday’s shallow Cumulus.  Even deeper clouds formed later in the afternoon and evening hours.  This image not left “blank” but has explanatory writing on it.

5:23 PM. Raindrops from heavy virga were beginning to reach the ground in several areas as evening approached. Overnight, a few fell on Catalina! These Cumulus complexes were likely more than 2 km thick, 6600 feet) topping out at temperatures well below -30°C (-22° F)

 

Not much ahead now.  Maybe a few more frosty Cu will form today… before things dry out and heat up.

The End.

Cumulus clouds, Definitions, Ice crystals, Science stories, Stratocumulus clouds, Sunsets

Drizzle and Stratocumulus bonanza

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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!

Altostratus clouds, Definitions, Lenticular clouds, Nimbostratus, Stratocumulus clouds, The weather ahead

50 actual shades of gray

Huh,  Sounds familiar.  Well, 50 shades of gray is a theme here at cloud-maven.com.  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