Category Archives: Cloud streets

The CDO roars after our 1.42 inches of rain

A few more hundredths fell after 7 AM yesterday, boosting our storm total to a remarkable 1.42 inches, January now about twice our long-term average.

Here’s what all that precip did to our beloved Cañada del Oro Wash:

3:53 PM. The CDO in full flow.
3:53 PM. The CDO in full flow at East Wilds Road, road closed.

Yesterday’s clouds

8:04 AM. A Stratocumulus overcast with areas of virga and light rain showers began the day.
8:04 AM. A Stratocumulus overcast with areas of virga and light rain showers began the day.

After a few more hundredths of rain, the skies broke open, and as we know well, some of our most spectacular scenes occur under deep blue skies punctuated by puffy Cumulus clouds, shadows and highlights on our now snow-capped Catalina Mountains.

10:36 AM. Cumulus clouds race toward Catalina borne on brisk southwest winds.
10:36 AM. Cumulus clouds race toward Catalina borne on brisk west winds.  In looking at this scene you can feel them coming at you.
10:36 AM. Deeper clouds capable of producing ice and precip still lay to the SSW of us.
10:36 AM. Deeper clouds capable of producing ice and precip still lay to the SSW of us.
11:19 AM. Heavy Cumulus line the Catalinas, spewing ice farther downwind.
11:19 AM. Heavy Cumulus line the Catalinas, spewing ice farther downwind.  Glinting rocks highlight the scene.
1:38 PM. Coming at you. The south end of the Tortolita Mountains is a common formation point in westerly and northwesterly flows for cloud street development, a line of clouds that stays in the same place, but elements are replaced.
1:38 PM. Coming at you. The south end of the Tortolita Mountains is a common formation point in westerly and northwesterly flows for cloud street development, a line of clouds that stays in the same place, but elements are replaced.
1:38 PM. The end of this cloud street shows that its tops got high enough to form a little ice, seen by that veil like cloud coming out the downwind end.
1:38 PM. The end of this cloud street shows that its tops got high enough to form a little ice, seen by that veil like cloud coming out the downwind end.
2:57 PM. Samaniego Ridge and its new coating.
2:57 PM. Samaniego Ridge and its new coating.
3:06 PM. Cloud streets continuing to stream off the Tortolita Mountains, but are now half the depth they were 2 h ago. No ice will form now.
3:06 PM. Cloud streets continuing to stream off the Tortolita Mountains, but are now half the depth they were 2 h ago. No ice will form now.
3:48 PM. "Devil's Post Pile" to the left of Samaniego Peak catches a sun break.
3:48 PM. “Devil’s Post Pile” to the left of Samaniego Peak catches a sun break.
4:01 PM. Last of the Tort cloud streets, shallower yet (estimated depth, 1000 feet) is about to fade into oblivion, wherever that is.
4:01 PM. Last of the Tort cloud streets, shallower yet (estimated depth, 1000-1500 feet) is about to fade into oblivion, wherever that is.

In the meantime, more highlights on Sam Ridge:

4:50 PM.
4:50 PM.  So pretty!
4:50.  Drawing back a bit for perspective on the scene.
4:50. Drawing back a bit for perspective on the scene.

Finally, that incredible sunset afterglow on our mountains:

5:46 PM.  I hope we never take such sights as yesterday's for granted.
5:46 PM. I hope we never take such sights as yesterday’s for granted.

 

The End.

Oops, oh yeah, storm tomorrow, supposed to begin in mid-day to afternoon hours.  Looks like a third of an incher.  Also looks to be a bit colder than the last storm, may see a flake or two by Tuesday morning.

Cold clouds and pretty, wintry scenes as long as they don’t last too long

What a gorgeous day yesterday was with deep blue skies dotted with Cumulus and one or two shallow Cumulonimbus, highlighted by our snow-capped Catalina Mountains.  After the brief warm up, more storms ahead for Catalina!

Yesterday’s clouds

DSC_0487
10:23 AM. By this time Cumulus were popping up all over, and with the temperature at just 10,000 feet above sea level (7,000 feet above Catalina) cloud mavens everywhere were pretty sure ice would eventually form in lots of Cumulus.
DSC_0490
10:24 AM. Shallow Cumulus congestus (left side) converting into an equally shallow Cumulonimbus capillatus (right half of cloud). This scene from a fairly primitive area of Arizona.
10:26 AM.
10:26 AM.  Pretty scene over Saddlebrooke.
DSC_0494
10:37 AM. Ice, there it is. Even shallow clouds spewed ice crystals and or small snowflakes (clusters of individual ice crystals.

Explanatory module below

The TUS balloon sounding, launched at about 3:30 AM yesterday morning from the campus of the University of Arizona Wildcats.
The TUS balloon sounding, launched at about 3:30 AM yesterday morning from the campus of the University of Arizona Wildcats.
DSC_0496
10:27 AM. Wintry scene #1, view toward the Charouleau Gap, and why do the French make spelling so hard?
11:04 AM. "Ice, there it is!", to paraphrase a song from "In Living Color."
11:04 AM. “Ice, there it is!”, to paraphrase a song from “In Living Color.”
DSC_0508
11:12 AM. Wintry scene #2. View is toward the Charouleau Gap.
DSC_0510
11:12 AM. Icy, but shallow Cumulonimbus cloud heads toward Catalina spewing a light rain shower and soft hail called “graupel.”
11:44 AM. Wintry scene #3.
11:44 AM. Wintry scene #3.
DSC_0526
12:32 PM. Not an advertisement for the University of Washington Huskies sports powerhouse, but rather a demonstration and graupel did, in fact,  fall from our shallow Cumulonimbus clouds yesterday.  BTW, the Washington Huskies play the NFL-ready, #1 Alabama Crimson Tide on New Year’s Eve at 1 PM AST in a fubbal playoff game.  It would be great if you watched, raising viewer numbers, and possibly therein,  the revenue stream flwoing into the University of Washington (from which I emanated). Oh, there appears to be a conical graupel there on the left. Graupel falling through a cloud of droplets often stays oriented with one face down, and that face collects all droplets that are freezing on it making that downward  facing side, as you would imagine,  bigger than the rear part, and so you get a pyramidal-shaped piece of soft ice. If it mainly tumbled on the way down through the cloud, it would be pretty spherical.  That white streak on the right is one that’s falling.
11:45 AM. Another ice producing candidate forms in cloud street aligned with Catalina.
11:12 AM. Another ice producing candidate forms in cloud street aligned with Catalina.  Couple of drops is all that came out of this.
DSC_0552
3:18 PM.  Very shallow, ice-producing clouds.  Few in the area had ice at this point in the afternoon, and a very tedious inspection of these clouds, comparing them with surrounding clouds,  suggested that their tops were just a bit higher than the ones around it that did not spew a little ice.
The TUS balloon sounding launched at 3:30 PM AST, also with writing on it.
The TUS balloon sounding launched at 3:30 PM AST, also with writing on it.
5:06 PM. Wintry scene #3 Pretty, eh?
5:06 PM. Wintry scene #4 Pretty, eh?
5:32 PM. Stratocumulus with red liner. Nice.
5:32 PM. Stratocumulus with red liner. Nice.

After the brief warm up ahead, still looks  “troughulent” and stormy in the SW as December closes out,  continuing into January.

The End

An unbelievably long blog about a surprise afternoon sprinkle of rain

A very few small, isolated drops fell between 4:50 and 5 PM here in Sutherland Heights from what appeared to be nothing overhead. You’d have to be really good to have not been driving, and to have anticipated the possibility (by recognizing ice in upwind clouds) and then having observed it.  You would be recognized, given some extra adulation,  at the next cloud maven junior meeting if you did observe it, that’s for sure.

So, a long blog about anticipating and observing a sprinkle of rain (RW—, “RW triple minus” in casual weatherspeak or text).

We start with some nice, but inapplicable to our main story photos from yesterday.

3:14 PM. Another one of those, to me, memorable, dramatic shots just because of cloud shadows on our pretty mountains caused by Cumulus humilis and mediocris clouds; Cirrus uncinus on top.
3:14 PM. Another one of those, to me, memorable, dramatic shots just because of cloud shadows on our pretty mountains caused by Cumulus humilis and mediocris clouds; Cirrus uncinus on top.
3:15 PM. Pretty CIrrus uncinus, "Angel's hair."
3:15 PM. Pretty CIrrus uncinus, “Angel’s hair.”
3:15 PM. Looks like a cloud street off the Tucson Mountains, one that streamed toward Catalina. Hope you were unbusy enough to notice it. Its a pretty common one here when the lower level winds are out of the SSW, and the clouds shallow.
3:15 PM. Looks like a cloud street off the Tucson Mountains, one that streamed toward Catalina. Hope you were “unbusy” enough to notice it. Its a pretty common one here when the lower level winds are out of the SSW, and the clouds shallow.
3:50 PM. Shadow quirk. The cloud shadow follows the terrain line. Wow. Never seen that before, but I suppose if you had an infinite number of monkeys watching, they'd see it all the time. Maybe they would type out some Shakespeare as well in time.
3:50 PM. Shadow quirk. The cloud shadow follows the terrain line. Wow. Never seen that before, but I suppose if you had an infinite number of monkeys watching, they’d something like this all the time. Maybe they’d type out some Shakespeare as well in time.
3:54 PM. While busy watching the cloud-sahdow dappled mountains, some honest-to-goodness Cumulus congestus arose in a line to the southwest! Not at all expected! Looks like they're tall enough to form ice, but don't see any. Will take too many photos to see if any develops though.
3:54 PM. While busy watching the cloud-sahdow dappled mountains, some honest-to-goodness Cumulus congestus arose in a line to the southwest! Not at all expected! Looks like they’re tall enough to form ice, but don’t see any. Will take too many photos to see if any develops though.
3:56 PM. That poor turret that first extruded from this line (center raggedy one) is being ravaged by "entrainment", that cloud killing process wherein the surrounding dry air gets in and kills off the droplets. Pretty sad when you think about. It also shows you just how friggin' dry the air was just above the main tops. No ice visible here.
3:56 PM. That poor turret that first extruded from this line (center raggedy one) is being ravaged by “entrainment”, that cloud killing process wherein the surrounding dry air gets in and kills off the droplets. Pretty sad when you think about. It also shows you just how friggin’ dry the air was just above the main tops. No ice visible here.
3:56 PM. Let's zoom in to be sure. Anyone saying they can see some ice in this is either an ice-detecting genius or just play lying.
3:56 PM. Let’s zoom in to be sure. Anyone saying they can see some ice in this is either an ice-detecting genius or just plain lying. BTW, that turret on the left, partially visible, is much taller, so its got a good chance to convert to ice.

Ann DSC_7808

3:58 PM. Now even little tiny babies can see the ice that formed in that now dessicated turret. This means some rain fell out of it! Wow, did not see that coming today.
3:58 PM. Now even little tiny babies can see the ice that formed in that now dessicated turret. This means some rain fell out of it! Wow, did not see that happening today.
3:58 PM. Pulling back to grab the whole scene, those Cumulus congestus clouds converting to small Cumulonimbus clouds that will bring those few tiny drops to Catalina in an hour.
3:58 PM. Pulling back to grab the whole scene, those Cumulus congestus clouds converting to small Cumulonimbus clouds that will bring those few tiny drops to Catalina in an hour even as the dry air up there wasted them. Real cloud mavens would be thinking about the possibility of rain here, seeing the ice form in clouds upwind of us, that right at that time! Congratulations!
4:09 PM. Doesn't look that great now, but areas of ice visible, and its heading this way with a light shower falling out of it! Maybe we'll pick up another trace!
4:09 PM. Doesn’t look that great now, but areas of ice visible, and its heading this way with a light shower falling out of it! Maybe we’ll pick up another trace! But what cloud name would you put on this scene? Well, its kind of embarrassing to call them “Cumulonimbus”, but we do have a suitable moniker for weakly-producing Cumulus ice clouds with a little precip, Cumulus congestus praecipitatio. Yep, that’s the name I would use here since the rain is reaching the ground (is not just producing virga).
4:30 PM. Code 1 rain shaft, a transparent one. We're going to a LOT of trouble for a trace of rain here! But, you should have been really excited by this time. The possiblity of rain is just minutes away, but you'll have to be outside to notice it!
4:30 PM. Code 1 rain shaft, a transparent one. We’re going to a LOT of trouble for a trace of rain here! But, you should have been really excited by this time. The possiblity of rain is just minutes away, but you’ll have to be outside to notice it!
4:40 PM. Drawing back to look at the whole scene, which is not that great. Bottom of sprinkle cloud has evaporated leaving that big patch of ice, left side of photo. Can the sprinkle heading toward us survive? Your heart probably was really pounding at this point since you wanted to see some drops so BAD, report that trace the next day, one that maybe only you would have noticed.
4:40 PM. Drawing back to look at the whole scene, which is not that great. Bottom of sprinkle cloud has evaporated leaving that big patch of ice, left side of photo. Can the sprinkle heading toward us survive? Your heart probably was really pounding at this point since you wanted to see some drops so BAD, report that trace the next day, one that maybe only you would have noticed.
4:47 PM. Three minutes to first drops, though here no drops would be reaching the ground from the condition the cloud is in now, its too high, just really anvil ice, and the ice crystals too small, The drops that are going to be intercepted are surely the last ones reaching the ground, the top of the sprinkle shaft, above which there are no more drops.
4:47 PM. Three minutes to first drops, though here no drops would be reaching the ground from the condition the cloud is in now, its too high, just really anvil ice, and the ice crystals too small, The drops that are going to be intercepted are surely the last ones reaching the ground, the top of the sprinkle shaft, above which there are no more drops.
4:55 PM. Drops are collecting on the windshield a few hundred yards from the house with almost no cloud aloft at this point!
4:55 PM. Drops are collecting on the windshield a few hundred yards from the house with almost no cloud aloft at this point! A trace of rain has been logged!

The End

(What about those gorgeous Cumulus congestus and Cumulonimbus calvus clouds over toward and well beyond Charouleau Gap about this time? Maybe later or tomorrow.)

“Just another day”, pretty much like the day before

Just Another Day“, btw, one of the many great songs by Oingo Boingo, if you’ve ever heard of them.  We’re not just about clouds here.  Trying to broaden your pop cultural knowledge with distractions like this.

Yesterday was remarkable  in how exact it was to the day before in clouds, but ultimately disappoiting.1  There was supposed to be more cloud action, shafting around, that kind of thing, but there wasn’t.  It was virtually identical in every way, including having only two clouds that got high and cold enough to have ice in them. I am sure you recorded them in your cloud diary, and this will be a little tedious as a result, but….what the HECK.

Here is your cloud day for yesterday, focusing on the detection of ice in clouds:

DSC_8007
1:15 PM. Not much going on.
DSC_8010
1:17 PM. Not much going on.
2:44 PM.
2:44 PM.  Not much going on, but nice cloud street.
3:23 PM.  Suddenly,  a narrow erection of cloud shot out of the larger Cumulus mediocris/congestus.  Would it form ice?  I was thinking so, and with that, maybe a rain shaft that could disrupt the wind field and trigger more buildups.  "Here we go," I was thinking, as you were as well.
3:13 PM. Suddenly, an erection of cloud (center at top)  shot out of the larger Cumulus mediocris/congestus. Would it form ice? I was thinking so, and with that, maybe a rain shaft that could disrupt the wind field and trigger more buildups. “Here we go,” I was thinking, as you were as well.
3:14 PM,  Looks pretty firm yet.  No indication of ice.
3:14 PM, Looks pretty firm yet. No indication of ice.  But definitely a few thousand feet higher  and colder than the surrounding cloud.
3:15:30.  Beginning to soften and fall back!  No sign of ice.  Those ragged edges represent the intrusion of dry air into the cloud called "entrainment."  Entrainment is less as the cloud shoots upward and contains vortex rings.  Worried now that this turret was not as high as initially perceived.
3:15:30. Beginning to soften and fall back! No sign of ice. Those ragged edges represent the intrusion of dry air into the cloud called “entrainment.” Entrainment is less as the cloud shoots upward and contains vortex rings. Worried now that this turret was not as high as initially perceived.
3:17 PM.  Stepping back and looking at the whole cloud, the top has been disconnected from the bottom by very dry air between where the top is now, and the lower part of the cloud.  Entrainment has beheaded this cloud!  And, no sign of ice...yet.
3:17 PM. Stepping back and looking at the whole cloud, the top has been disconnected from the bottom by very dry air between where the top is now, and the lower part of the cloud. Entrainment has beheaded this cloud! And, no sign of ice…yet.
3:18 PM.  Not much good up there, with no body, but ice is now visible, and is likely forming, as more of the cloud head evaporates.
3:18 PM. Not much good up there, with no body, but ice is now visible, and is likely forming, as more of the cloud head evaporates.  See that faint ice  veil below the head?
3:21 PM.  I am sure you can see the wisps of ice that this turret contained quite easily now.  Won't do much good decapitated like that.  Huh?  "Decapitated."  Seem to be on a religious theme today.
3:21 PM. I am sure you can see the wisps of ice that this turret contained quite easily now. Ice won’t do much good being decapitated like that with no cloud body to fall through and grow.. “Decapitated.”  Huh?  Seem to be on a religious theme today.  Must be due to that article I read in the Atlantic recently.
3:30 PM.  Twin towers, but like the one over Catalina, it faded into oblivion.
3:30 PM. Twin towers, and like the one over Catalina, it faded into oblivion after getting a little higher than ours, forming more ice.
DSC_8052
4:13 PM. Ever hopeful, but no, never  saw no ice from this tall boy,  phrasing here mindful of that classic new  old folk song, “Never did no wanderin’ ” by The Folksmen.
DSC_8063
7:26 PM. Nice storms elsewhere. Here, looking NE-E.

Today is another day.  More hope for a shower late today or tomorrow, models say, then likely another dry spell as the summer rain season ebbs again for awhile until that possible super hurricane Dolores drags some moisture up this way.  (Dolores, now just a tropical storm, was just born off southern Mexico near the coast.  Will be interesting to see just how strong she gets.

The End

——————-

1Some fans  like to see misspelled words here.  Amyone see that criminal who was sentenced to “life in person” as described in the AZ Star?  That was pretty grate.

Another Catalina rain day for May 2015

We received 0.08 inches here in “The Heights” for a third day with measurable rain in May already.  0.12 inches fell at the Bridge on Golder Ranch Dr. , while Saddlebrooke got up to a quarter of an inch (as estimated by CMP) in a tiny streak of clouds that erupted into shallow Cumulonimbus clouds, anvils and all yesterday afternoon between 4:30 and 5:30 PM. It was pretty much all over by 6:00 PM,  those shower clouds passing off toward Mammoth.

No rain was reported at mountain sites, to give you an idea of how localized that was, localized practically to Basha’s Market parking lot,  Sutherland Heights’ Equestrian Trail Road,  and Saddlebrooke’s Acacia Drive, to exaggerate some.

The astounding aspect of a tiny line of showers that suddenly erupted over and a little downwind of Catalina was that it was EXACTLY predicted  in the University of Arizona’s 5 AM AST model run yesterday morning, one whose results are available by mid-morning!  So, there would have been a few hours notice of possible rain here in Catalina.

There is no rain predicted in that model run anywhere else except in extreme NW Arizona, just that tiny ribbon of rain right over us, and the U of AZ “Beowulf Cluster” weather calculator got it right.

However, unless you were in the right spot, you might not have even known that it rained, the shower streak was so narrow.

Below, the astoundingly accurate predictions for 3, 4, and 5 PM for that model run from yesterday morning.  No rain whatsoever is shown at 3 PM, as you will see.
3pm

Ann 4pm

Ann 5pmTo be “fair”, NO RAIN was predicted anywhere NEAR Catalina by that same model crunching the data from 5 PM AST the evening before our little rain event, leading CMP to be a little asleep at the wheel yesterday morning, no blog.

Some cloud shots before and as this predicted (or unpredicted, as the case may be) rain began to happen.  Of course, if you want to go to the movies and see this, go here, from the U of AZ:  Yesterday’s cloud movie

DSC_6158
3:23 PM. Looking upwind. Nada going on, clouds to shallow for ice.
DSC_6165
4:04 PM. Hmmmm. Clouds definitely fattening up upwind of us in a nice cloud street from upwind of and over Pusch Ridge to Catalina. Nice scene, anyway, even if nothing happens.
DSC_6171
4:12 PM. Cumulus clouds are looking to gather down there at the corner of Pusch Ridge and Oracle Road, Huh. And they’re heading in this direction. Can ice really form in these guys today?
DSC_6172
4:23 PM. Clouds over and downwind of Pusch Ridge continuing to gather while heading toward Catalina. Looking for ice now or virga, but don’t see any anywhere.
DSC_6173
4:33 PM. Ice begins to show up in even modest clouds! And it started to show up everywhere in the form of virga. But then then the virga became thin shafts all the way to the ground. Cloud Maven Person is beside himself, but must go indoors for a social engagement!  Those of you who fancy yourselves as Cloud Maven Juniors, should have recorded this sighting of “first ice” in your cloud diaries for yesterday.
DSC_6176
Also at 4:33 PM. Ice is now readily visible in that Cumulus mediocris massing upwind of Catalina and is not about over the south part of the Catalina CDP (“Census Designated Place” that might one day be absorbed by Oro Valley, rumour has it.)
DSC_6180
4:41 PM. Just minutes before the first drops fall in Saddlebrooke, and CMP’s last photo of this incoming masterpiece of weather forecasting and little rain band; he can no longer comfortably jump up from dining room table in mid-conversation to say he has to pee again whilst actually taking a photo. You can only say you have to pee so many times in 10 minutes and still have your credibility intact. But, how can you say repeatedly, “I have to go look at some clouds?”, so I can’t hear the rest of your quite interesting story……”  Really came down for a couple of minutes several times there in Saddlebrooke between a quarter of five and 6 PM as one little raining cloud formed after another in this cloud stream.

Below,  sat view of this cloud streamer with radar, from IPS MeteoStar.  The image below is at the same time as the last photo above:

Satellite and radar imagery for 4:40 PM AST.
Satellite and radar imagery for 4:40 PM AST.  Note the many lines of clouds running almost due south to north into SE AZ from Mexico.

Here some more cloud stuff from the sounding launched at the U of AZ around 3:30 PM AST.

The TUS balloon sounding ("rawinsonde") for yesterday afternoon.  Looks like most tops were dabbling with the ice forming temperature of -10 C, but the sounding suggests that somewhat deeper tops could easily have arisen (and did!).  Interestingly, the model "knows" when ice forms, and it must have "known" that the ice-forming temperature was going to be surpassed in that little cloud line coming off Pusch Ridge.  Astounding, for the Nth time.
The TUS balloon sounding (“rawinsonde”) for yesterday afternoon. Looks like most tops were dabbling with the ice forming temperature of -10 C, but the sounding suggests that somewhat deeper tops could easily have arisen (and did!). Interestingly, the model “knows” when ice forms, and it must have “known” that the ice-forming temperature was going to be surpassed in that little cloud line coming off Pusch Ridge. Astounding, for the Nth time.  Bases were pretty cold, 0 C (32 F).

Here’s a diagram of when ice forms in the type of clouds we mostly have in Arizona, “continental” ones with high droplet concentrations, and when ice should form in them.  As you can see, ice should form in them soon after the top temperature gets colder than 10 C WHEN the base temperature is about what it was yesterday.

 

From a survey of the onset of ice formation in continental clouds by Rangno and Hobbs (1995)1
From a survey of the onset of ice formation in continental clouds by Rangno and Hobbs (1995)1

 

“CMP” is not mentioning it at all, but yesterday was another kind of mucked up sky, not a Catalina postcard sky,  with lots of aerosols making the sky a whitish-blue, the lower aerosol stuff again from Mexico, but there was also a layer far above the cloud tops, likely a long-range transport event from thousands of miles away.

This higher haze layer still seems to be around if you look toward the horizons right now (5:59 AM).

We’ll be between two jet streams today, kind of a jet stream sandwich, and the stronger one is now approaching from the northwest with that mega upper low over Cal.  That means no rain today, subsidence rules, though we’ll have small, non-ice producing Cumulus, and likely some Altocumulus lenticulars, maybe a Cirrocumulus patch here and there.  Should be a pretty nice day for cloud photos, haze aside.

The best chance for rain is still after midnight tonight into mid-day tomorrow as the core of the stronger jet stream goes just about over us.  Still thinking a tenth of an inch will occur here, though mod run from the U of AZ at 5 PM completely dry.   A little snow likely on Ms. Mt. Lemmon, too!

The End, FINALLY!  Brain empty.

———————————-

1From “A New Look at the Israeli Cloud Seeding Experiments.”

 

 

 

Surprise showers drop 0.02 inches in Sutherland Heights; April won’t be rainless!

Well, those showers were a surprise to “me and my model” yesterday morning, at least the one I looked at just before going on the air. There were no upstream echoes in the clouds upwind of us, either, something normally seen before cool season showers get here. Fortunately, I was able to get in a prediction that rain would fall just as the drops began coming down.

However, there are a few times when that bit more lifting as the air moves from the lower ground to the southwest of us to here can trigger precip; the tops get that bit colder, form ice, voila, out drops the rain (and snow).  That’s probably what happened yesterday to cause a sudden development of light showers, “all quads” it seemed.

Cloud tops may not have gotten colder than about -10 C yesterday, too, and so our rain likely fell from ice crystals rarely seen in Arizona, hollow sheaths and needles (columnar crystals), which have to be in big aggregates before they can form a drop big enough to reach the ground.   So, not only are they rare here, but there also have to be a LOT of them )10s to 100s per liter in the clouds) for them to form big enough snowflakes so that a drop reaches the ground.  In fact, when columnar ice crystals form in clouds, they often do so prolifically so that, at least at the University of Washington where the present Arthur worked for about 30 years in airborne studies of clouds, needles and sheath crystals were always associated with the highest concentrations of ice crystals that we observed.   Some of those rare ice crystals were STILL forming in the clouds above us  near the time of the second sounding, shown below,  launched at 3:30 PM!  That was really shocking!

This ice crystal happenstance, and the surprise light showers,  made yesterday particularly worth commenting on from this cloud pulpit, if that’s what it is.  Some nice examples of needle and hollow column ice are shown here at CalTech.  These kinds of crystals are rare in Arizona because they require larger (greater than 23 microns in diameter2 in clouds at temperatures between -3 and -8 C.  Like the needle crystals themselves.  Since the clouds were shallow, one has to speculate WHY the cloud droplets might have been extra large.  It may have been that there were few of them (seems kinda unlikely this far from  clean oceanic air.  More likely, those clouds had large (micron-sized) dust particles in them, known to help form larger cloud droplets.  So, I’m guess those clouds were helped by dust so’s they could have larger droplets in them, ones big enough to help produce ice splinters consisting of needle and hollow sheath crystals at such high temperatures (higher than -10 C).

Our U of AZ model predicted soundings were pretty much what we saw, too, cloud capped by a stable layer that got stronger as the day went on, and the air drier above it.  Below, from IPS MeteoStar, these TUS soundings from yesterday morning and afternoon.

Baloon (I prefer this spelling) sounding launched from the U of AZ yesterday morning around 3:30 AM AST.  Shows tops were marginal for ice in AZ at this time.
Baloon1  sounding launched from the U of AZ yesterday morning around 3:30 AM AST. Shows tops were marginal for ice in AZ at this time.
2015042500Z_SKEWT_KTUS
The baloon sounding from the 3:30 PM AST launch from the U of AZ.  Where the lines pinch together is the top of the boundary layer where cloud tops were, -10 C.  A few shocking rain drops fell in Catalina (stop light at Oracle and Golder Ranch Drive construction zone) soon after this launch (4:22 PM) from a shallow complex of Cumulus/Stratocumulus clouds. Unbelievable.  Carried out a little photo documentation when I saw them on my windshield to record the remarkable event.  It was pretty darn exciting, and I hope for you, too, if you felt a coupla drops about that time.

But let’s drag this out and look at yesterday’s clouds now…

DSC_5779
6:13 AM. Clouds much fatter than expected this morning, but nothing to worry about. Not gonna rain. Mod says so.
DSC_5780
6:14 AM. Looking to the north, not much, just some harmless Stratocumulus.  Maybe will go inside, not think for awhile….
DSC_5782
6:33 AM. Its raining over there, cloud has a tremendous amount of ice in tops (that smooth area to the right and above Pusch Ridge. Unbelievable, since the tops aren’t that high!
DSC_5783
6:34 AM. Another soft turret filled with ice trailing light rain! That softness suggests to this observer that they are not the usual ice crystals, but rather jillions of needle and hollow column (sheath) crystals, too.
7:38 AM.  By this time, the light showers were everywhere, especially in Oro Valley and drifted over Catalina for the next few hours.  Here. light rain, not haze, produces crepuscular rays.
7:38 AM. By this time, the light showers were everywhere, especially in Oro Valley and drifted over Catalina for the next few hours. Here. light rain, not haze, produces crepuscular rays.
3:29 PM.  By mid-afternoon, the clouds had gotten shallower, not warmer though, as bases rose more than the tops did.  Tops were still around -10 C at this time, but the bases were higher, above the mountains, as you can see here.  And, we had our usual "mountains shadows" (would be a nice motel name) light show.
3:29 PM. By mid-afternoon, the clouds had gotten shallower, not warmer though, as bases rose more than the tops did. Tops were still around -10 C at this time, but the bases were higher, above the mountains, as you can see here. And, we had our usual “mountains shadows” (would be a nice motel name) light show.

During the afternoon, a nice cloud “street” formed, came all the way from Mexico way, one that spawned a little more anomalous ice, and those few raindrops; see below for evidence if you don’t believe me.

DSC_5809
3:39 PM. Long cloud street trails over Catalina. Isolated veils of ice formed, with a few drops reaching the ground. See car front windshield below for the shocking evidence.
DSC_5816
4:20 PM. Raindrops fell on windshield as part of the long cloud street still in progress overhead. Grabbed camera immediately, of course, as this astounding event occurred! Was at the Golder Ranch Drive and Oracle intersection “war zone” as we would call it these days. (Hope they’re done before 2020. :}

BTW, here’s our cloud street as seen in the “visible” satellite imagery at 4 PM AST, just before the drops fell on my windshield.  You can see that it originated near the border with Mexico, as many things do.

Visible satellite imagery for 2300 UTC (4 PM AST) from the U of AZ.
Visible satellite imagery for 2300 UTC (4 PM AST) from the U of AZ.

The End, except I think there will be some more rain tomorrow morning, trace to quarter of an inch are the bounds, meaning about a tenth is the most likely amount from this cloud pulpit.

The End, again.

——————-

1I prefer this spelling today; more “o’s” than “l’s” in that word make you think more of a thing full of air; maybe a few more “o’s” would help even more, too,  like “baloooon”…

2That size is considered “large” for a cloud droplet, and lab studies have shown that they splinter when they hit something, like soft hail, also called “graupel.”  Splintering is thought to lead to all those extra ice crystals at temperatures between -3 and -8 C.

The streets of Marana-Oro Valley-Catalina, the cloud ones

In case you didn’t notice, there was a prolonged street of clouds emanating from possibly as far away as Kit Peak, or maybe just the Tucson Mountains. Lasted for a few hours.Happens only on days with relatively shallow clouds (cloud-topped boundary layer) with a little wind, meaning that the thermals from the surface heating ended up being capped by an inversion or other stable layer, and those thermals form clouds in some places.  In this case,  a long line of intermittent clouds formed from an initial air bump caused by those mountains far to the SW of us. CTBL is more often invoked as a term by cloud folks when the sky is much cloudier in low clouds than these shots from two days ago, such as when the sky is covered in Stratocumulus clouds.

These kinds of streets occur over the same places whenever a day like this comes along.  Think of it, especially here in Arizona, as a row of shady air under which you might like to live compared to those areas on either side of this cloud “street.”  In Seattle, where the “cloud topped boundary layer” is almost a daily occurrence, you want to avoid being under the cloud street, where it can block the sun, and instead find the clearer slots!

DSC_0147
12:14 PM.
DSC_0150
1:07 PM.
DSC_0153
3:19 PM. Barely hanging on now, but still present. Dissipated within about a half hour of this shot.

DSC_0160

 

TUS rawin for June 18th, 5 PM AST (launched about an hour and a half before that).
TUS rawin for June 18th, 5 PM AST (launched about an hour and a half before that).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For those sharpies that day and logged in their cloud diaries that ice formed in those shallow Cumulus clouds, they will be a little chagrined by this TUS sounding.  This sounding suggests the clouds around the balloon were topping at -8 C, too warm for ice formation in shallow Cu.   Let us begin to explain this puzzle by presenting evidence of ice formation in those clouds on the 18th:

4:13 PM.  Virga hangs down from Cu mediocris, maybe only a km thick  toward Charoleau Gap.
4:13 PM. Virga hangs down from Cu mediocris, maybe only a km thick toward Charouleau Gap.  Lots of ice visible.

 

4:13 PM.  Overhead view of likely ice vellum between Cumulus clouds.  The clouds themselves may well have a few ice crystals, but too few to provide any visual indication except in the clearings between them.
4:13 PM. Overhead view of likely ice vellum between Cumulus clouds. The clouds themselves may well have a few ice crystals, but too few to provide any visual indication except in the clearings between them.  Ice crystals evaporate more slowly than liquid drops when encountering sub-saturated air between clouds, and so can be visible a bit longer if present between clouds in marginal situations like this.  Confidence level that this little patch is ice and not just haze is about 70-80 percent.

Simple answer to our connundrum; due to lifting of the air as it approached and went over the Catalina Mountains, the tops of the clouds reached those temperature below -10 C where is begins to form.  We would guess even closer to -15 C in that cloud in the distance beyond Charouleau Gap due to the amount of ice.  Ice increases with decreasing cloud top temperature, but the temperature at which ice onsets can change on a daily basis; higher onset of ice temperatures on days in which the clouds have larger drops in their tops (a phenomenon originally reported by Ludlam in 1952, then re-discovered by Rangno and Hobbs (1988) who did not, at that time, know of the Ludlam finding, and thus, did not cite it.  Pretty embarrassing, really.  Was cited later in an update, however.

The weather way ahead

Seasonal rains beginning to show up in southern Arizona now on models beginning around the 4th of July as a big anti-cyclone parks itself over the Four Corners area in the latest model run from 11 PM AST last night.  Very excellent run.

The End

 

 

 

 

 

The cloud streets of Oro Valley

3:53 PM.  Three little rows of clouds are emitted from the Tortolita Mountains to the west, drift over Oro Valley.
3:53 PM. Three little rows of clouds are emitted from the Tortolita Mountains to the west, drift over Oro Valley.  These kinds of “streets” are there, and usually emit form the same spots, every time we have a moist, but shallow layer of air, and there’s a bit of wind.  We met men would call this situation a “cloud-capped boundary layer” where air rising to form these clouds doesn’t get any higher, usually due to a stable layer like an inversion.  The visual divergence, where one of the streets looks to be going to the left, and the one on the right going to the right,  is due to perspective.  Cloud streets are virtually parallel to one another.  The flow at cloud level was toward the photographer, me.  You got Cirrostratus on top of these Cumulus/Stratocumulus clouds.  (Where clouds like these are more isolated, we call them, Cumulus, when the same clouds group together into masses, we start calling them Stratocumulus.   Its kind of a fuzzy area in our fuzzy classification system (see Catalina cloud maven’s cloud classification article in the Encyclopedia of the Atmospheric Sciences, 6 vols., yours for $2258.20, “only one left in stock”, Amazon says, and the great Judy Curry, is Ed.–better get it before its gone!

 

5:03 PM.  That little zone on the Tortolitas is still pumping out the clouds.  Compare the back edge of this larger mass (which now would be Stratocumulus) with the origin point of the previous photo.  The cloud street is the one on the left that goes off the screen.
5:03 PM. That little zone (center, here) on the Tortolitas is still pumping out the clouds. Compare the back edge of this larger mass (which now would be Stratocumulus) with the origin point of the previous photo. The cloud street is the one on the left that goes off the screen.
5:32 PM.  That Cirrostratus steadily thickened as the afternoon wore on, almost making it look like another storm was moving in.   Cumulus filled in, too, becoming large areas of Stratocumulus, adding to the anticipation of a rain.
5:32 PM. That high Cirrostratus layer steadily thickened, becoming Altostratus here,  as the afternoon wore on.  Seemed like another storm was moving in.  Those isolated Cumulus clouds and their “streets” filled in, too, becoming large, dark areas of Stratocumulus, adding to the false anticipation of a rain as a storm skirted Arizona.

The weather way ahead after the upcoming heat wave

I have been staring at this weather Rorschach test for a few hours now, and there’s not much to say about it, except that there seems to be two eyeballs near the North Pole, and maybe one of the yellow lines forming a jaw down there toward Greenland, possibly a tilted drivers cap toward Russia.

Clearly the global patterns are “unsettled”, to use one of our favorite forecasting words.  (“We will have ‘unsettled’ weather over the next few days”, as one might say in Seattle most of the year.)

Below, “troughing” is suggested in the SW, but not much.  The Asian trough, anchored along the coast of Asia, is shown moving offshore here as it should during the spring, and that in turns helps form a trough downwind in the SW US, as we see happen in the spring over the long term (in climatology).   So we can only hang our hat on climo, that these uncertain times shown below in the plot below will resolve into something better than more drought.

We can also ponder the larger question of, “How’s come we can put a man on the moon and various space junk on Mars and can’t forecast the weather beyond about a week?”  Its crazy.

Or even the vastly larger question concerning chaos theory, a theory that rests on the phenomenon that small perturbations in the initial state of unstable systems are able to make huge changes over time, thus:

“Will a space probe, going off into deep space, as is happening now, an artifact that’s not supposed to be there, unsettle the unstable Universe?”

Valid for 1700 AST, March 17, 2014.
Valid for 1700 AST, March 17, 2014.

Pretty thoughtful blog today, I thought.  Usually don’t go this deep, but it just kind of happened.

The End, or is it?

Interesting sights; rain still on the Catalina event horizon

Too dark for the best sight, our 14-year old flat-coated retriever mix dog, at first seeming to be walking slowly up the dirt driveway in back of the house with another dog.  I could just make out two outlines.    I wondered whose dog had gotten out and was in our backyard?  Moving closer, I see that our dog is walking side-by-side up the dirt driveway, not with another dog, but with a javelina, like they’re buddies!  Then two more javelinas came out of the brush to join the slow walk uphill forming a peccary herd containing a dog!  After about 10 yards of this group slowly ascending the driveway toward me, the javelinas turned off into the brush.  Too dark for photos; dang.

—————————

Next, its raining in Tucson and I am eastbound on Prince Avenue about to turn left on to Oracle.   I was feeling good that its raining downtown, and it was not just here in Catalina that rain had fallen.  A car swerves across a lane in front of me to turn left on Oracle, and it turns out to be the best car ever evaluated by Consumer Reports!   Its the all electric Tesla Model S!

I am not a car buff, but this was a very great sighting for anyone knowing much about the direction cars are taking! Its made by a tiny company in Fremont,  California.  No gas used of course, its not a hybrid; you have to find a charging station.  But those stations are increasing pretty fast. You can go about 200 miles or so on a charge.

Anyway, if you have $90,000 or so, I think you should buy one right away.  No, really.  It would be worth it to be an “early adopter” and drive the market forward so that the price descends rapidly.

Yesterday morning in the rain, on Prince Avenue, a Tesla pulls in front of me! From the "Not-taken-while-driving" collection; this photo yours for $11,000.
Yesterday morning in the rain, on Prince Avenue, a Tesla pulls in front of me!  And, like me, they’re from Washington!
From the “Not-taken-while-driving” collection; this photo entitled, “Tesla in the Tucson Rain,” yours for $11,000 due to rain falling in Tucson simultaneously with a Tesla Model S sighting, an extremely rare combination of sights that your friends will envy.

————————

Sports AND clouds….

The Seattle Seahawks are in the Superbowl today.  The city where I worked is going bonkers over this because besides the team, they really like some of the players, like Russell Wilson whose really too small to be an NFL QB, and hasn’t been in jail ever.  The entire city has come together, including liberals and conservatives to root on the Seahawks! Reminds one of the afterglow of the first Gulf War when Arab cars were sporting American flags!

Cells in the rain

7:50 AM.  Rainsahft indicates a buildup in the tops above.  These were the kinds of cells that moved over Catalina during the early morning hours.  Likely would have looked like soft Cumulonimbus clouds if on top in an aircraft.
7:50 AM. This well-defined rainsahft indicates a buildup in the tops above. These were the kinds of cells that moved over Catalina during the early morning hours. Likely would have looked like soft Cumulonimbus clouds if on top in an aircraft.

 

9:43 AM.  Reflected light from the rain drops lingering on this blue palo verde gave it something of a lighted Christmas tree look.
9:43 AM. Reflected light from the rain drops lingering on this blue palo verde gave it something of a lighted Christmas tree look.
10:44 AM.  As the sun launches convective currents on a breezy day, and with some resistance to cloud top heights, lines of clouds form, something we call a "cloud street."  This one came all the way from the Tucson Mountains to the SSW of us.  When showers start to fall from these clouds, the downdrafts in them usually dissipate the line and it become chaotic, as happened over downtown Tucson later that morning.
10:44 AM. As the sun launches convective currents and Cumulus clouds on a breezy day, and with some resistance to cloud top heights due to a stable layer, lines of clouds form, something we call a “cloud street.” This one came all the way from the Tucson Mountains to the SSW of us to just about over Catalina.   When showers start to fall from  clouds lined up like this (because the tops have gotten high enough to form ice), the downdrafts in those showers usually dissipate the line and it becomes pretty chaotic and broken up into cells,  as happened over downtown Tucson later that morning.

 

5:26 PM.  By late afternoon there were some fabulous lighting scenes on the Catalinas, here looking NE toward Charouleau Gap.
5:26 PM. By late afternoon there were some fabulous lighting scenes under the Stratocumulus clouds on the Catalinas, here looking NE toward Charouleau Gap.

 

The weather ahead…

Looks like a minor rain in the works for Monday into Tuesday evening.  Probably will begin in the mid-day hours and probably will only produce a few hundredths to a tenths is all here in Catalina.  There’ll be more snow in the mountains, so that will be good to keep some of the creeks running.

The following storm, the one that looked substantial, has been diminishing in the model runs of the past day or so.  Dang.  The Enviro Can mod has given up completely on rain here in this trough that moves in on Thursday and Friday, the 7th and 8th.  Then, voila, the US one began to follow suit, though showing a less bountiful rain, but at least still has some beginning Friday the 7th and then has it dribbling into Saturday, the 8th (this from the 11 PM AST global run from last night).  Looking more like maybe a quarter inch of rain here in that one, but very dicey now in view of those Canadian calculations.  Sometimes their model does better than ours.

Still looking like a LONG, warm dry spell after next Saturday….

The End.

 

 

 

 

 

Filling in the blanks

Breezy, deep blue skies were pocked with Cumulus humilis (“humble”) but as the afternoon wore on, they became more numerous, and spread out to nearly fill the morning’s clear sky, while remaining “humble”; about the same depth, 1,000 to 1,500 feet, max.  Cloud tops were above freezing, so no chance to form ice and snowflakes, which would have fallen out as virga.  Nor was there a single Ac lenticular, as opined here that there might be one yesterday.

These kinds of days with scattered clouds producing shadows on our spectacular Catalina Mountains is one of the most mesmerizing.  If you can, you want to be somewhere where outside where you can see those shadows trek across our mountains,  their rocky faces highlighted and then dimmed, while another portion lights up highlighting some other characteristic of those mountains, particularly in the late afternoon when the sun light is that bit richer (due to traveling through a greater path of the atmosphere as it sinks toward the horizon and more of the harsher, shorter wavelengths of white light are scattered out).  Ask any photographer or artist.

And its no wonder we draw so many visitors in the cooler half of the year when there are so many days like yesterday; no rain, pleasant temperatures, but astounding, simple beauty just in the passing of a cloud shadow on a mountain.

3:11 PM.
3:11 PM.
3:11 PM, looking farther toward the south.  So pretty.  You can just sit there and watch these ever changing scenes for hours
3:11 PM, looking farther toward the north. So pretty. You can just sit there and watch these ever changing scenes for hours.  “Less doing, more watching.”
5:15 PM.
5:15 PM.
5:33 PM.  Even our dreaded cholla cactus can have so much beauty in the right light.
5:33 PM. Even our dreaded cholla cactus can have so much beauty in the right light.
4:19 PM.  Wonder how many of you noticed this line of small Cumulus clouds, called a "cloud street"?  At first I thought it was caused by a bounce of the air going over and around Pusch Ridge, but later it was clear it had origins far to the south.
4:19 PM. Wonder how many of you noticed this line of small Cumulus clouds, called a “cloud street”? At first I thought it was caused by a bounce of the air going over and around Pusch Ridge, but later it was clear it had origins far to the south.
5:29 PM.  Still going, but you can see the origin is not much related to Pusch Ridge as it shifted westward and extended overhead and downstream into Pinal County.
5:29 PM. “Cloud street” still going, but you can see the origin is not much related to Pusch Ridge as it shifted westward and extended overhead and downstream into Pinal County.  The clouds were filling in pretty fast at this time, but barely deepening.
6:07 PM.  While the sunset itself wasn't spectacular, the lighting on the mountains was.
6:07 PM. While the sunset itself wasn’t spectacular, the lighting on the mountains was. Aren’t you glad you live in Catalina?

——————————————————

In spite of overcast Stratocumulus clouds right now in the pre-dawn hours, there are no echoes on the radar anywhere near us.  Boohoo.

 

And, if you’ve read this blog, and studied its contents, taken all the quizes, you know its because the tops aren’t cold enough to form ice (generally requires -10 C, 14 F here), pretty much required for rain here in old Arizony. Of course, some of our citizens are older than “old Arizony” as a State, which is pretty darn amazing, so maybe it should be, “not-that-old-Arizony”, to depart from whatever it was I was going to say before thinking about “Arizony.”

Now, back to weather….   Looking at the satellite and radar from IPS MeteoStar, it would appear that there are enough clouds around that a sprinkle is possible before noon as an upper trough goes by today. The air will be getting colder aloft, and there appears to be a line of colder clouds in a band right now in western Arizona, maybe ones cold enough to do that. Measurable rain is a very remote possibility, however.

Another trough, very similar looking to this one today, with a blast of cooler air comes through on Friday, October 4th, but like this one, looks dry.  So, we have two pretty nice weekends in a row ahead of us as far as moderate temperatures go, and more great cloud shadows.

No rain for SE AZ in models for the next 15 days.  Dang.

The End.