Crepuscular rays “stairway to heaven”

Gray clouds appear over Catalina, then leave

You have to work with what you have. Imagine a day without crime, or an exploding balloon, traffic accident, tax folderol, etc., and the television news for that day is cancelled, not worthy of air time, maybe replaced with one of our favorite PBS programs, like, “The Desert Speaks”?

Had a nice lenticular a couple of days ago, in case you missed it.

Wasn’t up much that day; you know, the FLU! Its out there.

7:54 AM yesterday morning. Stratocumulus cloud tops Samaniego Ridge. Was actually hoping that the encroaching clouds would be cold enough to form ice even though models said no, tops would be warmer than -10° C (14°F) or so. However, in windy situations such as we had atop the Catalina Mountains, clouds like these can leave water in the form of “rime ice” on trees. How pathetic is that; we can only hope for some mountain sky water¹ through riming, not actual precipitation?

8:34 AM. Looks pretty good over there beyond Eagle Crest. Maybe there will be some ice in this deck after all… Or is that dust under that distant band?

8:45 AM. Wonder if something special is going on over there, maybe I should know about?

8:46 AM. Not much going on directly upwind, though Tucson Mountains obscured in dust. Of course, any cloud band is going to propagate, spread in, from the NW yesterday.

9:49 AM. Looking better. Now, if only some ice would form…

10:01 AM. Almost looks like precip. but its not. Note clouds still topping Sam Ridge, likely lots of rime icing gong on higher up, toward the middle and top of this shallow layer since the droplets are too small at cloud base to produce riming. Higher up in the clouds like these, the droplets will reach the size (about about 15 um in diameter) where they are large enough to collide with objects and freeze onto them.

10:01 AM. A closer look at a dust-infused crespucular ray that almost looked like fine precip.

11:56 AM. The Stratocumulus deck is thinning, but an anomalous darkening has appeared, either due to the shadow of a lenticular cloud or a large space vehicle on top of the lower Stratocu. Note that the clouds have now lifted above even Ms. Mt. Lemmon. No more riming to add to our aquifers. No actual precip was recorded in the county.

12:38 PM. The clearing side of our little cloud band as it slud by, the complete clearing zone to the right. Tucson Mountains still mostly obscured in dust, though it really wasn’t that windy here.

1:41 PM. Waiting for the electrician…. If you can find a sunny porch out of the wind, its amazing how pleasant 52°F can be. BTW, if you need an electrician badly, but it conflicts with open heart surgery, its best to cancel the open heart surgery; you may never get another chance to get a licensed, bonded electrician out, but you can always have open heart surgery on another day. The above, our former home, rented for so long, now in the process of being sold. (boohoo).

No real change apparent in the drought pattern.

The End

Looking back; your updated Catalina water year and summer rainfall graphs

Let’s face it, for most of the people living in Arizona, their best years are in the rear view mirror, as are mine which were probably about 50 years ago… Following that thought, let us not look ahead to further declines, but rather look back at the last water year for Catalina, ending this past September 30th, and see what it says, if anything, about the changing global climate we hear so much about:

Your Catalina water year history, compiled through 2008 by the folks at Our Garden there on Stallion Avenue off of Columbus where great, and fresh organic vegetables can be purchased every Wednesday and Saturday morning. Tell them Art sent you! — Your Catalina water year history, compiled through 2008 by the folks at Our Garden there on N. Stallion Rs. off of Columbus Blvd. where you can find fresh organic vegetables every Wednesday and Saturday morning. Tell them Art sent you! Haha.

Can’t say I see too much going on here in Catalina so far; things seem pretty stable in the precipitation arena for the full water year’s rainfall.

I point out again, with great redundancy since I have pointed this out before, that the Our Garden climate record started just as a monumental change in circulation patterns occurred. Most climate scientists would attribute that to a shift as due to the Pacific Decadal Oscillation, discovered by important scientists I know well, like Mike Wallace¹, of the University of Washington Huskies Atmospheric Sciences Department where I worked for about 30 years, but in airborne studies of clouds.

The PDO shift, if that’s what done it, was a circulation pattern change that brought astoundingly wet conditions to Catalina and the whole Southwest US, wet conditions unlikely to be seen in our remaining lifetimes, which aren’t that much longer anyway.

You may remember that bristle cone pine tree rings in California, analyzed by Haston and Michaelson in 1994, found only one period in the last 600 years (!) that was as wet as the late 1970s into the 1980s there (certainly spilling into AZ).

Remember how the Great Salt Lake was filling up to record levels back in the 1980s?

And any long term resident here, like the ones that I have spoken to, will tell you about the days of yore when the washes around here were running all year.

Well, that wasn’t the norm. sadly. They were just so lucky to have seen that era.

In weather, what goes around, comes around. Count on it happening again at some point in the future IMO. (Some climate changers might disagree with this assertion.)

How about our summer rainfall, June through September. Well, here’s that graph, updated through this past summer! Hope you like it:

Not much going on here, either.

Yesterday’s clouds–another day, another rainbow, of course.

Sprinkles of rain occurred off and on all day yesterday, but couldn’t muster even one hundredth of an inch of rain! With a few exceptions, the clouds producing the rain weren’t too deep, though still icy ones, and pretty high off the ground, mostly above 8,000 to 9.000 feet above us, which doesn’t help.

First, a rainbow shot:

4:20 PM. Maybe, following the example of the University of Hawaii (Rainbow Wahini), the Banner University of Arizona should call themselves the Rainbow Wildcats... — 4:20 PM. Looking north toward the Charouleau Gap (on the right). We have so many rainbows in Arizona, maybe, following the example of the University of Hawaii (Rainbow Wahini), the Banner University of Arizona sports teams should call themselves the “Rainbow Wildcats”…

4:42 PM. Here's a problem for a great shaft of rain, sloping tops of Cumulonimbus clouds. Don't see any shaft here, just rain. When tops slope like this, it indicates the updraft isn't very strong and the ice in the cloud is going to collect little in the way of "supercooled" cloud droplets, that would stick to the ice, eventually making it a graupel or soft hail particle, the kind of thing that our vertical shafts are largely comprised of aloft. Slopey tops mean not a lot of growth of the precip, more "stratiform" like rain with fewer is any pulses of big drops. — 4:42 PM. Here’s a problem for a great shaft of rain, sloping tops of Cumulonimbus clouds. Don’t see any shaft here, just rain. When tops slope like this, it indicates the updraft isn’t very strong and the ice in the cloud is going to collect very little in the way of “supercooled” cloud droplets because the ice that forms is ejecting downstream from where the greatest growth would occur due to collecting cloud droplets, ones that would stick to the ice crystal, eventually making it a graupel or soft hail particle, the kind of thing that our vertical shafts are largely comprised of aloft. Slopey tops mean not a lot of growth of the precip, more “stratiform” like rain with fewer is any pulses of big drops.

5:31 PM. Of course, still another rainbow. Notice how the colors are not as vibrant as some rainbows. This would indicate the concentrations of drops are less, and smaller than in the bright ones. So, not a lotta rain falling over there.

3:50 PM. Now here's a shaft with a real top, a pretty vertical one above it. There were a couple of these. Once again the spaces between the shafts lined up to pass over Catalina, rather than the shafts. The Tortolita Mountains got most of this one. I love these scenes, though, so many times resulting in disappointments. — 3:50 PM. Now here’s a shaft with a real top, a pretty vertical one above it. There were a couple of these. Once again the spaces between the shafts lined up to pass over Catalina, rather than the shafts. The Tortolita Mountains got most of this one. I love these scenes, the backlighting, though, so many times they have resulted in disappointments.

4:01 PM. The "Torts" cleaning up with a decent rain as that complex passed over them. — 4:01 PM. The “Torts” cleaning up with a decent rain as that complex passed over them.

5:19 PM. But even with a rain disappointment, we get to see these scenes here in The Heights over and over, again and again, to add to redundancy, We are so lucky! The cloud line above the mountains would be Stratocumulus.

5:21 PM. Here crepuscular rays of sunlight produced by falling light rain diverge from the sun's position. Light from an "infinite" source is supposed to be parallel at great distances. This seems to prove that our reality, as is sometimes suggested by philosophers, is not what we perceive with our brains, and the sun is much closer to us and much smaller than generally believed by astronomers... — 5:21 PM. Here crepuscular rays of sunlight produced by falling light rain diverge from the sun’s position. Light from an “infinite” source is supposed to be parallel at great distances. This seems to prove that our reality, as is sometimes suggested by philosophers, is not what we perceive with our tiny human brains. These diverging rays demonstrate that the sun is much closer to the earth and much smaller than generally believed by astronomers… The true reality of life and the universe are sometimes right in front of us.

5:37 PM. By this time, the crepuscular rays and the existential questions they raised were gone and reality was back to normal. Here a pretty good Cumulonimbus with a pretty vertical top and big shaft heads in the general direction of Catalina, once again raising hopes for measurable rain. — 5:37 PM. By this time, the crepuscular rays and the existential questions they raised were gone and our perceived reality back to normal. Here a pretty good Cumulonimbus with a pretty vertical top and big shaft heads in the general direction of Catalina, once again raising hopes for measurable rain. Instead, it faded to sprinkles and our total rain from them was only a trace.

The End

—————–

¹Well, actually we said “hi” in the halls once in awhile, I gave a talk in his class once, and, along with a bunch of Atmos Sci faculty, got to watch the 1992 New Year’s Day Rose Bowl mash down of Michigan for the Washington’s 1991 NCAA Division I fubball championship at his house. He also mediated an authorship kerfluffle between Peter Hobbs and me.

Eruption! CDO ran big last night (updated with golf balls shown in the wash))

This just in

Just back from a horsey ride with Zeus the horse. Rode into the CDO to see the surprising view that it had run bank-to-bank last night after that mighty cell passed by along the foothills. In the wash, were golf ball-sized golf balls scattered throughout the wash, indicating that it hit the planned community of Saddlebrooke with it many golf courses very hard. No golfers were found.

The Pima County ALERT gauges really did not call out that such a flow would occur from precip data around here, the greatest amount being barely over an inch, and its likely that such a flow in the CDO, bank to bank would need 2-3 inch dump in its watershed.

This morning around 10 AM in the CDO south of the E Golder Ranch Drive bridge,

———-end of updated material unless I get more updated——

After an afternoon of “steady-state” Cumulus congestus and small Cumulonimbus clouds trailed northward from the Catalina Mountains, the “Mighty Kong” erupted about 5 PM providing one of the most intimidating, yet majestic and beautiful scenes of the summer rain season; this or any.

Cloud Maven Person was indoors drowning his sorrows concerning what appeared to be a a grotesquely failed forecast of a good rain day (“about half an inch”) here in Catalina in flavorful Indian cuisine when the unexpected began to take place outside. So, the photo record is incomplete for this event. “CMP” had given up on the day.

Just measured in NWS-Style 8-inch gauge and CoCoRahs gauge:

0.12 inches was our total here in the Heights.

And, the photos aren’t quite as good as they should be, slightly out of focus since CMP didn’t adjust his camera for the dark scenes his was seeing. Oh, me. Missed the great sunrise, too, due to not having memory stick in the camera! Oh, me.

The day started propitiously enough with a ton of clouds, and a line of weak Cumulonimbus heading for us from the S and SW. A small Cb can be seen on the left. — 6:48 AM. The day started propitiously enough with a ton of clouds, and a line of weak Cumulonimbus heading for us from the SW -W. horizon. A small Cb ahead of this line can be seen on the left.

7:14 AM. Looking at this scene, and pondering a day of these, "CMP" is wondering just how many inches of rain we might have, — 7:14 AM. Looking at this scene, and pondering a day and evening of these, “CMP” is wondering just how many inches of rain we might have,

However this line faded, bringing only sprinkles, a trace of rain to Catalina, and was followed by a huge clearing and sunny skies, thought to be a good thing at the time. Soon, gigantic Cumulonimbus clouds would erupt to over the mountains all quadrants… Nope. By mid-afternoon, only Cumulus congestus had formed with an occasional bit of ice and rain visible, all to the north.

2:08 PM. Cumulus congestus repeatedly formed in the lee of the Catalinas. Occasionally one produced a shower. The clouds are moving from right to left in southerly flow, probably pinching together in the lee of the Catalina Mountain “sky island” as happens in the lee of real islands.

4:21 PM. Another nice Cumulus congestus, but where's are the Cumulonimbus clouds, the big line coming in from the S and SW? Pretty much threw in the towel, gave up except to document for purposes of training a little conversion from water to ice visual lesson in one of these turrets that climbed just high enough to convert. — 4:21 PM. Another nice Cumulus congestus, but where’s are the Cumulonimbus clouds, that big line of them coming in from the S and SW? Pretty much threw in the towel, gave up except to document for purposes of training a little conversion from water to ice visual lesson in one of these turrets that climbed just high enough to convert.

4:25 PM. Thus in a series is just 5 min long. Shows how fast the liquid looking cloud can convert to one that is all ice and droplets evaporate due to incursions of dry air, and their molecules race over to that ice crystal next to them. When water and ice are together, its supersaturated with respect to ice, and water molecules head toward any ice around, accumulating as a solid on the ice (a process called deposition), racing over there as a vapor.

4:27 PM. A very slight change has taken place. The tight cauliflower look due to liquid water “cells” (such as those on the left side where a new turret is rising up) are disappearing, Its not very obvious at all, but you should be thinking even with this little bit of change, “There she goes! It made it to the “glaciation level” today.”

4:28 PM. Underneath this converting turret are ice particles that are just starting to fall out. Can you see the little fibers of ice? Since they don’t have a long water path to fall through, these would be pretty pristine ice, maybe only lightly “rimed” covered in frozen cloud droplets. Notice to here and in the next shot, that they are sloping a bit, indicating they’re not heavy ice particles at all. If you’re really good, you can see that the whole turret has changed, no longer looks “watery”; that tight, hard, cauliflower look has “mellowed”, the crenelations have mostly disappeared. What is a “crenelation” anyway? Better look it up….

4:30 PM. Its a gonner here, no liquid water is left in that turret. The question we still struggle with is how this conversion happens so fast?

This was the last photo I took until walking out of a local Indian restaurant and exclaiming, “What? When did this happen?” It was so clear to the S-W with the exception of a single dissipating Cb that it didn’t even seem worth a photo.

6:04 PM. Hope! — 6:04 PM. Hope for that great, meaningful rain in Catalina, though I am in Rancho Vistoso when shooting this.

6:04 PM. Looking over the Catalina Mountains as much as I could. Look at that nice, solid base!

6:08 PM. Luxurious shafts of rain begin to pour out of solid cloud bases. And look at the one protruding outward toward Rancho V. THis is looking incredible for something humongous to happen. Not sure why this happened? Was there a trigger aloft that was going over this late in the day?

6:11 PM. Now, a rainbow to boot! This shot from Honeybee Canyon Park.

6:13 PM. This is becoming something memorable. Losing control, photos every minute or so, but ISO level too low!

6:14 PM. In the meantime a shelf of clouds, Stratocumulus I'd say, spreads westward from the storm. — 6:14 PM. In the meantime a shelf of clouds, Stratocumulus I’d say, spreads westward from the storm. Would they, could they erupt, too? No, as it turned out.

6:16 PM. As dark fell and the rainbow faded, it was now becoming evident that this late eruption was becoming something special. The rest of the time was spent racing home to be there when it hit Catalina/Sutherland Heights. — 6:16 PM. As darkness fell at Honeybee, and the rainbow faded, it was now becoming evident that this odd late eruption was becoming something special. The rest of the time was spent racing home to be there when it hit Catalina/Sutherland Heights.

6:26 PM. Got this shot waiting at the light at Rancho Vistoso Blvd and Oracle Rd. By this shot, I am thinking, unbelievable what has happened! This has become the "Mighty Kong" of summer storms. — 6:26 PM. Got this kind of crummy shot waiting at the light at Rancho Vistoso Blvd and Oracle Rd. By this shot, I am thinking, unbelievable what has happened! This has become the “Mighty Kong” of summer storms, and its spreading away from the mountains toward Sutherland Heights!

6:33 PM. Car was blasted going down Golder Ranch Drive by not blowing dust but blowing gravel as outflow winds slammed down Golder Ranch Drive. Estimated gusts 60 mph. Afraid to look at front of car this morning. Also look at how firm, solid that leading base is, telling you that there is a strong updraft feeding into it. More cells will develop downwind. That's Jenny and Matt's house shining in the sun on the hillside. — 6:33 PM. Car was blasted going down Golder Ranch Drive by not blowing dust but blowing gravel as outflow winds slammed down Golder Ranch Drive. Estimated gusts 60 mph. Afraid to look at front of car this morning. Also look at how firm, solid that leading base is, telling you that there is a strong updraft feeding into it. More cells will develop downwind. That’s Jenny and Matt’s house shining in the sun on the hillside.

6:33 PM. Looking from Golder Ranch Drive toward Samaniego Ridge, obscured in rain.

Well, as it turned out it was a near hit, only 0.06 inches fell in a violent few minutes of huge drops at my place in Sutherland Heights. From what I saw going by, and needing 0.44 inches on yesterday morning’s forecast of 0.50 inches in Sutherland Heights. about 500 yards farther west for this remarkable, dramatic storm would have given us that amount easily. 1.06 inches was recorded at Cargodera Canyon, NE corner of Cat State Park, and several sites in the foot hills of Catalina toward the mountains area had more than half an inch.

A quickie take on a U of AZ model run from last evening’s global data, has Cumulonimbus clouds developing to our southwest and rolling across Catalina in the afternoon. This would be, appropriately, considering the definition of the end of our summer rain season as September 30th, very appropriate.

The End.

Evening thunderstorms roll across Catalina with apocalyptic cloud scenes

Some apocalyptic cloud scenes can be Cumulus that explode suddenly into Cumulonimbus, and Cumulonimbus clouds with their foreboding (unless you live in a desert) rain shafts, and their predecessor shelf clouds like “swirly dark Stratocumulus”, and arcus clouds, the latter, a lower line of clouds just above and a little behind the wind shift at the ground, usually just ahead of the main rain shaft. While we didn’t get to see an arcus cloud yesterday, we had some dramatic swlrly dark Stratocumulus clouds to scare us. I say “swirly” because if you looked up yesterday evening as they passed over, you would have seen rotation in them.

These can combine, as they did yesterday, to make you think someone might drop out of the clouds and fix the world¹. See those scary photos below, way below as it turns out.

This monster collection of Cumulonimbus clouds (“mesoscale convective system” or MCS in weather lingo) with swirly shelf clouds preceding it barged over Catalina later yesterday afternoon after it appeared that not much was going to happen all day. Heck, there wasn’t even a decent Cumulus over the Catalinas until after 2 PM!

The result of this system slamming Catalina was the usual strong preceding winds roaring down from Charouleau Gap way and points north or northeast. The winds were not as damaging as three days earlier.

Then the rain! So nice! Got 0.55 inches of rain here in Sutherland Heights, an inch and half on Samaniego Ridge, and 1.65 inches on Ms. Lemmon.

Worth watching is the U of AZ weather departments time lapse video, especially beginning at 2 min 50 s into it. That’s when the big group of Cbs begins to make its presence known from the east. What is interesting, and what I have not seen before, is that you will see the tops of a thunderhead farther west, that icy part up around 30,000 to 40,000 feet, shoved backwards (back toward the west) by outflow at the tops of the huge incoming system. Very dramatic.

Yesterday’s clouds

1:30 PM. Yawn. Its 103 F, dewpoint 60 F. Baby Cu begin dotting the Catalina Mountains.

2:14 PM. Cumulus congestus finally arises within the local cloudscape. Looks like the top is high enough to convert to ice.

Detour: detecting ice in clouds….some practice shots

As the burgeoning cloud maven junior person you, of course, know how important the appearance of ice in our clouds is. You got ice; you got precipitation, which is snow up there, soft hail, hail, frozen drops.

2:19 PM. The declining right side of this cloud has ice in it, but its hard to detect for most observers. Only the BEST of the cloud-mavens could scream out, “there it is!”, before its more obvious to the less gifted CMJPs.

2:22 PM. Well, too easy now to see that there's ice in those little fingers extruding out from the body of the cloud; evaporation of the cloud drops has left the slower evaporating ice "naked" so-to-speak. It also in the higher turret, and would be termed a "calvus" topped Cu, properly, Cumulonimbus calvus, though not much fell out of it. — 2:22 PM. Well, too easy now to see that there’s ice in those little fingers extruding out from the body of the cloud; evaporation of the cloud drops has left the slower evaporating ice “naked” so-to-speak. It also in the higher turret, and would be termed a “calvus” topped Cu, properly, Cumulonimbus calvus, though not much fell out of this one, close to Saddlebrooke.

3:31 PM. In the meantime while I wasn't looking, Mt. Lemmon erupted sending a plume of cloud droplets which converted to ice skyward to at least 35,000 feet ASL. — 3:31 PM. In the meantime while I wasn’t looking, Mt. Lemmon erupted sending a plume of cloud droplets, higher up, ice, skyward to at least 35,000 feet ASL. Indicated a phenomenal amount of instability afternoon, instability that was about to be realized in a line of mammoth Cumulonimbi.

3:49 PM. "Eruption" just about over. Notice how skinny the root is now, AND that the top of the stem of convection is now only about half as high as in the first shot. Like a wild fire plume that has cooled off, the plume height goes down. Still formed ice on the right side, as you SHOULD be able to see. You should also be guessing that those were likely warmer habit crystals, like needles and sheaths. I did, if that's any help. — 3:49 PM. “Eruption” just about over. Notice how skinny the root is now, AND that the top of the stem of convection is now only about half as high as in the first shot. Like a wild fire plume that has cooled off, the plume height goes down. Still formed ice on the right side, as you SHOULD be able to see. You should also be guessing that those were likely warmer habit crystals, like needles and sheaths. I did, if that’s any help.

4:38 PM. Another cloud jack (Cumulonimbus eruption indicating a whole lotta instability), tops probably far above 40,000 feet. A lower portin of the anvil drifts southward toward Catalina. This one was dumping somewhere near the Biosphere 2 landmark. Note that anvil, lower right. That was our incoming major complex of Cum

5:17 PM. WOW! This was magnificent, and just one of the many large Cumulonimbus clouds racing toward the Catalina Mountains. This is the one that in the video, the crown of it can be seen forcing the air over us in the opposite direction. Still, it was not certain at this time these storms would make it here. And, this is looking ESE, while the storm movement was from the ENE.

5:25 PM. The "Menace of Charouleau Gap". Many of our worst storms roll in from the ENE, toward Charouleau Gap, and many who have lived here will tell you and this is the archetypical seen for those storms. A sudden blackening of the sky beyond Charouleau Gap. These darker clouds are rarely the ons producing the storms, but are riding a strong NE wind surging toward Catalina, about to produce some mayhem. The winds always arrive before the rain. And, as a few days ago, there are times when ONLY the wind arrives, there is not enough instability aloft to allow the storms to drift past higher terrain without falling apart. — 5:25 PM. The “Menace of Charouleau Gap”. Many of our worst storms roll in from the ENE, toward Charouleau Gap, and many who have lived here will tell you and this is the archetypical seen for those storms. A sudden blackening of the sky beyond Charouleau Gap. These darker clouds are rarely the ons producing the storms, but are riding a strong NE wind surging toward Catalina, about to produce some mayhem. The winds always arrive before the rain. And, as a few days ago, there are times when ONLY the wind arrives, there is not enough instability aloft to allow the storms to drift past higher terrain without falling apart. On this day, they will make it.

5:48 PM. I am going to work this scene over because it is associated with one of the more spectacular storm sequences here in Catalina, one that comes up usually a few times every summer. The anvil outflow aloft is thickening and lowering, and the outrider shallow Stratocumulus are racing out and along the Catalina Mountains. Things are changing incredibly fast and the NE wind is about to hit.

6:05 PM. Walking the dogs to beat the rain, The NE wind has hit, the power line wires are howling. The sky continues to darken and look ominous, but....no rain shafts have come over the mountains, a cause for concern. — 6:05 PM. Walking the dogs to beat the rain, The NE wind has hit, the power line wires are howling. The sky continues to darken and look ominous, but….no rain shafts have come over the mountains, a cause for concern.

6:21 PM. The shallow clouds ahead of the rain area continue to spread down and out from the Catalinas. A small opening in the clouds allows this dramatic highlight. I like highlights.

6:22 PM. Let's look a little closer at this spectacular highlight. — 6:22 PM. Let’s look a little closer at this spectacular highlight. Wow! This is just as good as a bolt of lightning.

6:33 PM. Maybe time to get the Good Book out, cram for the finals.... This was really quite the sight, considering it had been so sunny just a couple of hours before. Again, these are fairly shallow clouds riding the outflow winds, now gusting 35-45 mph in Sutherland Heights. The mottled bases here indicate that there is no organized wide updraft to launch them into deep Cumulonimbus clouds at this moment, anyway. — 6:33 PM. Maybe time to get the Good Book out, cram for the finals…. This was really quite the sight, considering it had been so sunny just a couple of hours before. Again, these are fairly shallow clouds riding the outflow winds, now gusting 35-45 mph in Sutherland Heights. The mottled bases here indicate that there is no organized wide updraft to launch them into deep Cumulonimbus clouds at this moment, anyway.

6:34 PM. Finally, a major new rain shaft emerges over Samaniego Ridge, upstream of Catalina!

6:35 PM. Looks like more and more people are dropping off Word Press as these files are going in pretty easy now. Here, the apocalyptic cloud formation rolls down and out across Oro Valley, with heavy rain just to the left. — 6:35 PM. Looks like more and more people are dropping off Word Press as these files are going in pretty easy now.Here, the apocalyptic cloud formation rolls down and out across Oro Valley, with heavy rain just to the left.

6:43 PM. A rare sight, wind driven rain streaming off the tops of the foothills of the Catalinas. The winds were likely hurricane force (>64 mph) to do this. — 6:43 PM. A rare sight, wind driven rain streaming off the tops of the foothills of the Catalinas. The winds were likely hurricane force (>64 knots, 74 mph) to do this. Samaniego Peak received 1.50 inches during this storm.

7:21 PM. Sunset in Catalina, July 29th. The sun does not have a sharp disk because the light is being scattered by large particles like rain drops. When its smog, the particles are of the order of micrometers and a sharp disk will be seen. — 7:21 PM. Sunset in Catalina, July 29th. The sun does not have a sharp disk, is rather blurry, because the light from the sun is being scattered by large particles like rain drops which bend the light so that we can’t see the disk’s outline. When its smog, the particles are of the order of micrometers and a sharp disk will be seen because the sunlight is not bent around large particles. I think Einstein said that…

7:21 PM. Orange and rainy as sunset procedes as usual.

Only the largest hailstones up there can make it to the ground as such here in Arizona due to our high summertime freezing levels. The rest melt into raindrops, some of which are large enough to reach the ground. Those downpours that suddenly emit from cloud bases were always hail or graupel (soft hail) aloft.

Sometimes in deep stratiform clouds attached to clusters of Cumulonimbus clouds, and with especially moist air from the base of the stratiform layer to the ground, clusters of ice crystals we call snowflakes make it to the ground without evaporating as steady light or very light rain.

Last night as our storm was coming to an end, it is likely that THOSE drops were once snowflakes rather than soft hail or graupel.

The End (finally)

————————————–

¹Huh. Maybe that wouldn’t be a bad thing. I am very concerned about microplastics (particles 5 millimeters and smaller) in our oceans, resulting from the breakup of larger plastic items we’ve been throwing in the oceans for decades. Seems those tiny particles are getting into everything, including the fish out there! It would be great if someone could get rid of them.

Forgetting about our mud for a moment; thinking of the danger to others as seen in future weather maps

Have had 1.75 inches here in the Heights last few days. Horsies are tromping around in significant mud.

But, to resume a theme about others from the prior entry, those in California, they’d better be paying close attention to the weather a week and more out. In this weather watcher’s opinion, which should count for something, California may be in for an unforgettable January.

Why?

Recall how those “ensemble-spaghetti-Lorenz” plots had an unusually constrained (contours of flow, red and blue lines that were unusually bunched together all the way from Hong Kong to ‘Frisco even 10-15 days out? That indicated a high confidence forecast of where the jet stream would be.

USUALLY, the contours are pretty wild, scattered all over the eastern Pac after about 10 days or so, and Cloud Maven Person got overly excited about this esoteric part of weather forecasting, and decided to write a partially decipherable tome on it.

Well, that constrained jet, blasting into Cal from the subtropical latitudes with a terrible ferocity, has continued in model run after model run now, and CMP’s excitement has been further elevated, maybe to penthouse level now, hard to elevate it more.

Way below are a few examples from just last night’s model run based on global obs at 5 PM AST, showing a few sample of the jet stream predicted pattern at 500 millibars, or around 18, 000 feet (from IPS MeteoStar, as usual).

THESE are extraordinary maps, and extraordinary maps mean extraordinary storms, AND they are appearing with extraordinary consistency.

They are also compatible with what we saw in those ensemble-spaghetti plots of a few days ago. So, like the “Frankenstorm” of 2010 that hit California, this series of strong storms hitting Cal in just over a week, will be considered to have been “well-predicted” by those crazy plots.

Is FEMA ready?

I think they will be involved at some point.

But, too, this is a forecast series where we (those in Cal) have lots of time to get ready for big, destructive events.

Like what?

For Cal, the usual.

1) Huge waves smash the coast, some home roll into the ocean. With a jet having a gigantic fetch from the Pac, huge waves are a certainty, surf will definitely be up, if that’s what you do because the surface winds will ALSO have a huge fetch to build those giant rollers.

2) Winds. At some point, hurricane force winds blow stuff around in one of more of the low centers generated by such a powerful jet stream. Looking at the pattern, I think one within this storm series may produce 100 mph winds or more somewhere in Cal.

3) Flooding. Can the nearly empty Cal reservoirs we’ve heard so much about be filled up in a series like this, something that might go on for one to two weeks? I think so, some anyway. But this is a truly wild thought, and as you can see, CMP is kind of out of control here.

It is certain that the rains with one or more of the low centers that slam the West Coast during this series will produce rains of 10 or more inches in a day in the hill and mountain regions of Cal.

Also, the series begins with a strong, but maybe not exceptional storm about 8 days from now, this after a pretty good rain has already occurred, so the ground is going to be pretty wet when the Big Series hits.

The jet stream pattern strengthens and shifts farther south with each day after this first major storm, and that’s when the real onslaught will hit.

I don’t want to get people overly excited like I am, but I am terming these, and the whole recent series of unbelievable jet streams bashing into Cal, and even Baja!, “the California calamity maps.”

2016010900_WST_GFS_500_HGT_WINDS_240 — Valid, Monday, January 18, 5 PM AST.

Skipping ahead:

2016010900_WST_GFS_500_HGT_WINDS_312 — Valid Thursday, January 21st, at 5 PM AST. EGAD! WHAT a monster!

2016010900_WST_GFS_500_HGT_WINDS_336 — Valid 5 PM, January 22nd. One blast is finishing up, but look at the jet entering on the left/west side. Once again, “egad!”

Skipping ahead some more….

2016010900_WST_GFS_500_HGT_WINDS_384 — Valid at 5 PM AST, January 24. Upper cut to jaw of Cal from the Pacific. This one would be quite bad in rain, wind, floods.

Now the timing of these things WILL VARY as the mod runs keep churning out results, but in CMP’s view, the pattern that will cause CA havoc is locked in now, promulgated ALMOST without doubt by our Big Niño.

Here is another amazing map from a prior run, that just makes your jaw drop due to what the models are sensing is “out there” for Cal and the West Coast:

This is looks like it was for another planet, the jet SO POWERFUL and heading into Baja!

Crespuscular rays due to light rain from precipitating Stratocumulus (i.e., “praecipitatio.”, if you want to impress your friends.)

Pretty good sunset color. The clouds? Stratocumulus.

Weather station and mountain sunset color. You don't see that too often.... — Weather station and mountain sunset color. You don’t see those together too often. Mountains topped by non-precipitating Stratocumulus clouds.

How will SE AZ do?

Seems like passing rains will hit during this CA bludgeoning period, but floody weather not expected.

Since we’re pretty much at our average total for the month of January right NOW, CMP is going out on a limb and predicting an above normal total for the WHOLE month.

The End

Raining in puddle just ahead, but not on car; also, a horse picture

This was amazing. I approach one of the puddles on Equestrian Trail. I see that its raining HARD in the puddle. I am only 20 feet from it, but its not raining on my car! Here’s what that scene looked like:

3:26 PM. Equestrian Trail road puddle outbound from Sutherland Heights.

How could this be? Of course, we’ve all seen heavy rain on the road and drove into it. But the illusion here that was so striking is that it only SEEMED to be raining in the puddle, not around it since the drop splashes were not obvious as I drove up to it.

The rest of yesterday was pretty great, too, lots of rainbows, brilliant clouds and skies, too photogenic for a neurotic-compulsive photographer. However, one of 221 photos was of a human, a neighbor, not of clouds and rain shafts.

Here are a few too many cloud photos; excess is kind of a specialty of mine:

11:58 AM. Cumulonimbus cloud boils upward upwind of Catalina.

12:25 PM. Getting closer.... — 12:25 PM. Getting closer….

12:51 PM. Lightning strikes not that close... — 12:51 PM. Lightning strikes not that close…Hail up to pea size, though.

1:10 PM. Backside of storm looked pretty good, too, quite firm and protuberant. Note whitish fallstreak, likely graupel and or hail. — 1:10 PM. Backside of storm looked pretty good, too, quite firm and protuberant, indicating updraft still intact. Note whitish fallstreak, likely graupel and or hail.

1:43 PM. Crepuscular rays due to rain, not haze. A pretty scene sez me.

2:36 PM. Biosphere 2 hit by light rainbow.

2:42 PM. For the sharp-eyed, bit of arcus cloud below Cumulus bases shows the northwest wind and cold front about to hit Catalina. Hit over there by Marana first. Was minutes away here.

2:46 PM. Something akin to an arcus cloud is just about on Catalina. Remember, the shift of the wind precedes the cloud, and lifts the air above it. Did you notice how the whole sky began to fill in with clouds as the windshift hit and for the hours after that? Pretty cool, huh?

3:56 PM. Awful dark out for this time of day. And yet another rainbow! Is this Hawaii, or WHAT? Rainbow colors end where snow is falling, not rain.

4:05 PM. Day closes with more storms drifting toward Catalina.

Lightly looking ahead

Still a lot of “troughy” weather ahead, and chance for decent November rains in the first half of the month after cold one goes by, followed by a short dry spell.

The End.

Loud May rain totals 0.47 inches in Sutherland Heights, Catalina

After last evening’s surprisingly heavy rain, we have now met our average for May for Catalina, having received 0.47 inches of rain over the past 24 h, some 0.36 inches during some house-shaking thunderclaps last evening.

Below are the 24 h local totals, ending at 4 AM today from the Pima County ALERT gauges rolling archive , these totals pretty much capturing all of our beautiful storm:

    Gauge    Location
    ID#
    —-     —-       —-        —-       —-         —-       —————–            ———————
Catalina Area
    1010     0.63      Golder Ranch                            Horseshoe Bend Rd in Saddlebrooke
    1020     0.83      Oracle Ranger Station          approximately 0.5 mi SW of Oracle
    1040     0.55      Dodge Tank                   Edwin Rd 1.3 mi E of Lago Del Oro Parkway
    1050     0.75      Cherry Spring                approximately 1.5 mi W of Charouleau Gap
    1060     0.79      Pig Spring                   approximately 1.1 mi NE of Charouleau Gap
    1070     0.39      Cargodera Canyon             NE corner of Catalina State Park
    1080     0.63      CDO @ Rancho Solano       CDO Wash NE of Saddlebrooke
    1100     0.35      CDO @ Golder Rd              CSO Wash at Golder Ranch Dr

Santa Catalina Mountains
    1030     1.18      Oracle Ridge                 Oracle Ridge, 1.5 mi N of Rice Peak
    1090      0.35      Mt. Lemmon                   Mount Lemmon
    1110      1.34      CDO @ Coronado Camp          CDO Wash 0.3 mi S of Coronado,       1130          0.83      Samaniego Peak               Samaniego Peak on Samaniego Ridge
    1140      0.79      Dan Saddle                   Dan Saddle on Oracle Ridge
    2150     0.24      White Tail                   Catalina Hwy 0.8 mi W of Palisade RS
    2280     0.24      Green Mountain               Green Mountain
    2290      0.12      Marshall Gulch               Sabino Creek 0.6 mi SSE of Marshall Gulch

For more rainfall info, go here and here. And here to the USGS, too, not to mention the NWS rainfall tables. Too bad they can’t all be in one gigantic table!

The clouds and weather just ahead

A little cold morning rain, and even snow on The Lemmon, is looking likely for Saturday morning. Presently, the core of the jet stream at 500 millibars or around 18,000 feet associated with a mighty upper cold low that sits on Arizona on Saturday is forecast to be south of us (as was yesterday’s jet), a pretty black and white discriminator for cool season (Oct-May) rain here.

However, if that jet core around the low does not circumscribe TUS, you can forget rain. From IPS MeteoStar, this rendering of the upper level configuration for Saturday morning, showing that it WILL circumscribe TUS:

The 500 mb heights and winds predicted for 5 AM AST, Saturday morning, May 10th. Its gonna a cool Mom's Day, too. One would expect rain here in Catalina with this configuration. Note how max winds are in a band well south of us. That banding circumscribes the deeper parts of the Pacific moisture that came in with this trough. — The 500 mb heights and winds predicted for 5 AM AST, Saturday morning, May 10th. Its gonna a cool Mom’s Day, too. One would expect rain here in Catalina with this configuration. Note how max winds are in a band well south of us. That banding circumscribes the deeper parts of the Pacific moisture that came in with this trough. This rendering is from the global crunch of data taken at about 5 PM AST, yesterday evening. These runs are updated every six hours.

In the meantime, “troughiness” today, tomorrow and Thursday, with secondary jet stream to south of us, will give us some more photogenic high-based Cumulus, maybe with some with virga in the afternoons. Today, as our upper low says goodbye, subsiding air is supposed to keep clouds from attaining tops high and cold enough to form ice. So, no rain today.

Yesterday’s clouds (going deep, as in pedantically)

There were some great scenes yesterday, summer-like ones, odd for May here, with massive rainshafts as the cloud bases lowered, reflected a huge jump in surface dewpoints to summer-like values in the mid-50s. Cloud bases yesterday morning, riding the tops of Samaniego Ridge, were near 7 C, compared with -5 C the afternoon before.

This warming of cloud bases greases the precipitation “wheel” since clouds with warm bases are be able to rain easier than ones with cold bases (say, near or at below freezing temperatures). Droplet sizes have to be larger at any given level above cloud base compared to the clouds of the day before since more moisture is forming in those updrafts at the higher base temperature. And, oddly, the larger the droplets, the higher the temperature at which ice can begin forming in clouds. And when ice forms, snow, then rain, come out the bottom.

To go on too long on this in covering all rain possibilities for yesterday, a base temperature of 7 C here is on the edge of being able to produce droplets big enough so that some begin colliding with one another and sticking together so that drizzle, then raindrops can form, a couple to a few thousand feet above cloud base, and those sizes of drops can really accelerate the formation of ice and then rain out the bottom. Are there any readers left? I doubt it.

Let us go even deeper…. It was hazy, smoky looking yesterday most of the morning, even when some good thunderstorms formed. So what? Well, smoke is bad for storms. Remember when it was reported by Warner and and the U of Arizona’s own Sean Twomey (1967) that sugarcane burning made it stop raining downwind from those fires in Australia? That effect has been verified in satellite measurements by cloud seeding nemesis, Danny Rosenfeld² of the HUJ in Science a few years ago.

Well, too much smoke can choke droplet sizes down and inhibit the formation of rain by collisions, and delay the formation of ice. And so we had that counter effect of smoke from somewhere, maybe LA this time since it was in the boundary layer, not aloft like that smoke layer from Asia was a couple of weeks ago.

So, cloud microstructurally-spekaing, it was an especially interesting day, one, if he were cloud maven person, wishes he would have had an aircraft to sample them.

But let us look now and see what all the fuss is about:

5:40 AM. Dewpoints in the 50s, Stratocumulus clouds top Samaniego Ridge! — 5:40 AM. Dewpoints in the 50s; Stratocumulus clouds top Samaniego Ridge!

6:41 AM. Soft-serve Cumulonimbus forms over west Tucson, Oro Valley. Icy top looks like its comprised of needles and hollow sheaths to me, ice that forms at relatively high temperatures for ice formation, higher than -10 C.

6:42 AM. In the meantime, drama over Oro Valley to the west and north of Catalina as a deeper cloud unloads. Thunder, too.

7:19 AM. Haze and rain. This was a pretty astounding sight, so much haze/smoke in the rain as evidenced by these intense crepuscular rays.

8:19 AM. A real summer-looking sky on a big rain day. Frequent lightning was emitted by this behemoth that went on to pound Saddlebrooke.

8:37 AM. Unusually strong May thunderstorm pounds Saddlebrooke.

3:42 PM. In spite of lots of convection and scattered Cumulonimbus clouds, the sky remained almost an eastern whitish due to smoke, which I will blame on southern California, absent any facts or investigation. No time.

3:42 PM. In spite of lots of convection and scattered Cumulonimbus clouds, the sky remained almost an eastern whitish due to smoke. — 8:37 AM. Unusually strong May thunderstorm pounds Saddlebrooke.

3:42 PM. In spite of lots of convection and scattered Cumulonimbus clouds, the sky remained almost an eastern whitish due to smoke, which I will blame on southern California, absent any facts or investigation. No time.

6:59 PM. Our major evening rain and thunderstorms were developing upstream.

The End

————————————-

¹Warner, J. and S. Twomey, 1967: The Production of Cloud Nuclei by Cane Fires and the Effect on Cloud Droplet Concentration. J. Atmos Sci., 24, 704–706.

²Rosenfeld a “nemesis?” See the references and discussion below for kind of an interesting science story aside….

Rangno, A. L., and P. V. Hobbs, 1997a: Reply to Rosenfeld. J. Appl. Meteor., 36, 272-276, and…..

Rangno, A. L., and P. V. Hobbs, 1997b: Comprehensive Reply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp.

With the publication of voluminous (en toto) commentaries/critiques in 1997 by a few of our peers, but mainly by Danny Rosenfeld of the Hebrew University of Jerusalem, that concerned our 1995 paper reanalyzing the Israeli randomized experiments, yours truly and Peter V. Hobbs, had attained, according the the Technical Editor of the Journal, the status of having become the most criticized meteorologists in the history of weather–well, in the history of the Amer. Meteor. Soc. journals, anyway! How fun is that? Its fun.

Our findings, that the two benchmark Israeli randomized cloud seeding experiments conducted in the 1960s and 1970s were largely misperceptions of cloud seeding effects due to storm biases on seeded days, were independently verified in peer-reviewed publications by researchers at Tel Aviv University some many years later.

Operational cloud seeding has ended in Israel in favor of more fruitful avenues for obtaining the water they so badly need.

4.63 inches; enhancing our historic storm due to “further review”

First, a tedious note about the Big One of two days ago.

While the Davis Vantage Pro 2 tipping bucket gauge registered a whopping 4.18 inches, a smaller plastic gauge from CoCoRahs here had 4.63 inches, after subtracting some rain (half an inch) I forgot to dump due to a brain cramp. A neighbor a couple hundred yards away here in Sutherland Heights, measured 4.65 inches in her gauge, and I now think that the 4.63 inches is the correct amount of rain for this spot. This goes with two other reports of 4.48 inches at Our Garden, and another one of 4.50 inches just a bit on the west side of Lago del Oro Parkway, and the 4.59 inches at the Samaniego Peak ALERT gauge just E of us. We seem to have been in the heaviest band of that storm! (Makes up for all the misses during the summer.)

The Vantage gauge is mounted above the ground, and some loss occurs due to wind, and also when the rain falls too hard, the tipping bucket can’t keep up. The CoCo gauge is ground mounted, and is protected from wind by surrounding natural desert vegetation (aka, “weeds”).

Below, from the University of Arizona’s rainlog.org, is a map of rain totals in our area and the northern areas of TUS. (The Our Garden and Samaniego Peak totals of 4.48 and 4.59 inches, respectively, don’t show up because they are not members of rainlog.org but probably should be so’s we can get all the rain we want to see in one site! I have added those values

Ann TUS rainfall 9-9-2014 fell prior day — Rain totals for September 8, 2014. The green values are for Our Garden and Samaniego Peak, along with the revised total for Sutherland Heights. Recall a neighbor here measured 4.65 inches!

In the meantime, from CDO at Wilds Road videos I took in heavy rain as the Sutherland Heights rain started to eclipse 3 inches, this larger wave that formed. I think it could have been surfed.

10:55 AM. From a frame of a video taken at the CDO wash and Wilds Road intersection, this monster. Must have been 6 feet high! — 10:55 AM. From a frame of a video taken at the CDO wash and Wilds Road intersection, this monster. Must have been 6 feet high in total height! So, you CAN “surf Arizona!”

Yesterday’s clouds

First of all, it was real disappointing to see so much haze in the air after so much rain! Not sure where it came from yet, will have to do some back trajectories to find out, but later…

6:54 AM. Crepuscular rays outline a Cumulus turret.

6:54 AM. Distant Cumulonimbus offers hope for a similar scene later in the morning over the Catalinas, a scene that was NOT realized.

8:17 AM. A great example of crepuscular rays and bad air.

12:53 PM. Promising Cumulus congestus that really went nowhere.

2:03 PM. However, it was not a completely rainless day. Some clouds got thick enough to rain lightly. In this Arthur's opinion, this rain was due to the collision with coalescence rain process, not the ice one which I deem with a 51% confidence level. — 2:03 PM. However, it was not a completely rainless day, as can be seen, “dead ahead.” Some clouds got thick enough to rain lightly. In this Arthur’s opinion, this rain was due to the collision with coalescence rain process, not the ice one which I deem with a 51% confidence level.

4:26 PM. Kind of losing interest in the whole day now as Cu disappear in favor of an Altocumulus opacus deck, one originating right out of Norbert if you saw the satellite imagery.

The weather ahead

Still pretty confident in more summer rains and tropical air after the current dry spell of a few days, this partly associated with the next tropical storm, likely to be named “Opal” or something like that with an “O” as it takes shape. Of course, we could look up what name it will be, but it will be named soon enough, so why bother?Its already a numbered tropical depression (a weak area of low pressure) down there off Guatemala now.

Much adieu about nothing (i.e., no rain)

There are a lot of photos here of yesterday’s clouds, considering it was a day with no rain. Oh, well, pretty normal for a cloud-centric person where the least cloud minutiae is somehow “interesting.”

8:13 AM. Very gratifying and a little surprising to see the first tiny Cu spring up so early in the morning off'n Lemmon. But, would it be only shallow moisture? — 8:13 AM. Very gratifying and a little surprising to see the first tiny Cu spring up so early in the morning off’n Lemmon. But, would it be only shallow moisture?

10:13 AM. Also a promising sign, a thin turret rising out of a blob of small Cu. Mr. Cloud Maven Person apologizes in advance if this shot is somehow offensive. — 10:13 AM. Also a promising sign, a thin turret rising out of a blob of small Cu. Mr. Cloud Maven Person apologizes in advance if this shot is somehow offensive by suggesting a middle finger.

10:52 AM. Clouds mass above Ms. Lemmon, BUT, can they reach the ice-forming level where the temperature is as low as -10 C (14 F) or lower so that they can rain? I'm thinking it'll be close, but was not real hopeful. — 10:52 AM. Clouds mass above Ms. Lemmon, BUT, can they reach the ice-forming level where the temperature is as low as -10 C (14 F) or lower so that they can rain? I’m thinking it’ll be close, but was not real hopeful.

11:19 AM. Amazing! On this expected to be dry day, Ms. Lemmon and her environs have created a Cumulonimbus cloud! Nowhere within a hundred miles was there another cloud like this!

11:19 AM. Zoom of the icy "calvus" top in the middle (its not very fibrous yet, but is clearly loaded with ice, unlike the crinkly turret at left. Sometimes that "calvus" look is compared with the look of "cotton candy." You remember, cotton candy don't you? — 11:19 AM. Zoom of the icy “calvus” top in the middle (its not very fibrous yet, but is clearly loaded with ice, unlike the crinkly turret at left. Sometimes that “calvus” look is compared with the look of “cotton candy.” Within about 10 s, there was a rumble of thunder! You remember, cotton candy don’t you?

12:56 PM. Pretty clear here that the day was done as far as Cumulonimbus clouds are concerned as the drier air moving in the from the west took it toll, and well as the cooling of the mountains by the prior thunderstorm. Or was it done? CM thought so, but maybe I shouldn't tell you that, causing you to lose confidence. — 12:56 PM. Pretty obvious here that the day was done as far as Cumulonimbus clouds over the Cat Mountains are concerned as the drier air moving in the from the west began to take its toll, as well as the cooling of the mountains by the prior thunderstorm. Or was it done? CM thought so, but maybe I shouldn’t tell you that, causing you to lose confidence.

1:50 PM. A truly shocking sight to CM. The Cumulonimbus clouds were able to start up again!

2:04 PM. Mr. Cloud Maven Person enjoys showing you how fast cloud tops can glaciate, and this was a nice case. — 2:04 PM. Mr. Cloud Maven Person enjoys showing you how fast cloud tops can glaciate, and this was a nice case (Cb calvus stage here).

5:23 PM. Well, it was all over by this time, no more Cbs, but here's a Cumulus mediocris showing crepuscular rays (ray features due to high aerosol content of the air). — 5:23 PM. Well, it was all over by this time, no more Cbs, but here’s a Cumulus mediocris showing crepuscular rays (ray features due to high aerosol loading of the air).

7:32 PM. Nice pastel colored Cirrus spissatus cumulonimbogenitus (I couldn't stop with just "Cirrus", I had to ruin it with a long unpronounceable part. Oh, well, that's what cloud-maven person does. — 7:32 PM. Nice pastel-colored Cirrus spissatus cumulonimbogenitus (I couldn’t stop with just “Cirrus”, I had to ruin it with a long unpronounceable part. Oh, well, that’s what cloud-maven person does.

Next and maybe last rain of the summer (kidding only a little) looks to be around August 3rd still. Flow aloft looking awfully grim overall for summer rain in Catalina mod longer term predictions… This may be the worst thing I have ever said to a desert people during their “wet” season. Let’s hope we have about 5 inches on August 3rd or so!

Traced yesterday, BTW

I wonder if you caught it? Fell between 8:10 and 8:12 AM. Very isolated, and pretty small drops. If you weren’t driving in it, or outside, you would never have known this happened. But observing and reporting events like this is what makes us who we are, you reader of CM. We take pride in seeing and observing what others don’t.

8:12 AM. Documentation of the total rain event on a car window. — 8:12 AM. Photographic documentation of the total rain event on a car window, zoomed view. The largest raindrops are about 1 mm in size.

Before the rain hit, some two or three RW– (weather text version of “very light rainshowers”) began to fall to the SW of us from that deck of Stratocumulus clouds. Must have been where the tops were higher than anywhere else. Here’s the first sign, and upwind of Catalina, that you, as a CMJ (cloud maven junior) know to pull your car out of the garage. (BTW, thinking about having a CMJ cookie drive next month…so look around for your best recipes.)

7:42 AM. A full 30 minutes before the trace event in Catalina, a weak shaft of rain is observed by Twin Peaks. — 7:42 AM. A full 30 minutes before the trace event in Catalina, a weak shaft of rain is observed on Twin Peaks, part of a broken line of sprinkles-its-not-drizzle rain.

It may seem strange, a non-sequitor, for those blog passersby to be talking about taking your car out of the garage or carport if a slight amount of rain might occur, as was the case yesterday. Here’s the “skinny”, as we used to say in the last century when we were young and could do things: a “clean” car, one that been wiped of all evidence of prior rain drops, but one having a thin coating of dust (you don’t have to apply a thing dust layer, its goes with the territory here) is great as a “trace detector.” And for us, CMs and CMJs, observing a trace such as yesterdays, when ordinary observers miss it (fumble the ball), is like hitting a low outside slider from former Husky pitcher Tim Lincecum, for a game winning touchdown. Or Boise State beating Oklahoma in a bowl game.

Why not just use the radar instead of parking your car outside and if the 24 h depiction of precip shows an echo over you, just mark yourself down as having a “trace”?

That would be cheating! Besides, some echoes seen on radar are only aloft.

And what if you’re in a “data silent” zone, where the radar beam is blocked by terrain, or is too far away? You’re adding unique information with your trace. Sure, nobody around you really cares if you had a trace or not, but, what the HECK.

8:01 AM. Heavy looking cloud produces sprinkle on the Tortolitas. Looks so dark partly because of the time of day, and partly because there was a fair amount of aerosol in the air. When it gets into clouds, it causes the drops in them to be small, and when small, they reflect more light off their tops and the bottoms appear darker. — 8:01 AM. Heavy looking cloud produces sprinkle on the Tortolitas. Looks so dark partly because of the time of day, and partly because there was a fair amount of aerosol in the air. When higher aerosol concentrations get into clouds, it causes the drops in them to be small, and when small, they reflect more light off their tops and the bottoms appear darker. But it also indicates that the clouds are thicker than surrounding clouds, there’s a mound on the top. Still, among those higher droplet concentrations must have been drops large enough to collide and stick together and become small raindrops.

Did the tops reach -10 C or so to form ice and cause this shower? Nope. Capped out at 0 to -5 C, so almost impossible to have had ice form to cause our sprinkles. Check this sounding from the WY Cowboys, who are off to a good season BTW.

The Tucson sounding for 5 AM AST yesterday morning during our cloudy conditions.

In examining this TUS sounding closely, its good to remember that we are NOT Tucson, but in Catalina. We are 14 miles from the city limits; have a road sign that sez so. “Hey”, we aren’t even on the same side of the mountains as is “Tucson.” In fact, you have to go through the city limits of Oro Valley to get to Catalina! Only the Post Office thinks that Catalina is in “Tucson.” OK, got that in…

And, during the cooler season when troughs go by, as yesterday, the temperature profile from Tucson balloon is not accurate for us here in Catalina; its always that bit colder to the north and west of the balloon launch site for days like yesterday. So, like a chef, adding that bit more of butter or garlic, OUR sounding should be tweaked from the TUS one to show slightly higher and colder cloud tops, probably near – 5 C, not at ZERO or slightly cooler in overshooting Cumulus/Stratocumulus tops as would be expected from the Tucson sounding. Also, since it sprinkled at 8 AM, and not 5 AM, its also likely that clouds tops were going up some as the trough from the west approached yesterday. So there are lots of possibilities.

Sure wish we’d had a PIREP! (Texting form of, “Pilot report”). Any CMJ’s out there have an aircraft that we could take up and kind of poke around up there, see for sure what really happened instead of “hand waving”?

Absent aircraft reports, I am going to say that almost certainly yesterday’s sprinkle was a case of rain formed by “collisions with coalescence, or via the “warm rain” process (called that because it doesn’t have ice), sometimes called here, “coalision” rain. Very unusual in Arizona and, you can see that if you have to park your car outside to see how much came out of a cloud producing rain through “coalision”, it doesn’t amount to much.

You know, this is a great story for you. First, you observe rain that no one else did, or even cares about, until maybe you tell them it was almost certainly caused by collisions among cloud droplets, and then watch their eyes bug out!

Had some spectacular highlights again on the Catalinas, and also evidence of the aerosol loading as we say, in the crepuscular rays (colloq., crepsucular) shown below.

8:03 AM. Evidence of smog, maybe some dust, too, aerosols that were getting into our clouds yesterday. — 8:03 AM. Evidence of smog, maybe some dust, too, aka, aerosols that were getting into our clouds yesterday.

SONY DSC — 8:04 AM. Gorgeous highlights continuously moved across the Catalinas. Hard to stop watching, snapping photos like mad, HD filling up, not much room left, gasping for more empty sectors now.

1:39 PM. Its all over. Only a field of small Cumulus ("humilis") are left. Photo taken from inside a horse corral to give it a western flavor, maybe make you feel more comfortable after a heavy dose of "science-hand waving." — 1:39 PM. Its all over. Only a field of small Cumulus (“humilis”) are left. Photo taken from inside a horse corral to give it a western flavor, make it more accessible to reader, maybe make you feel more comfortable after a heavy dose of “science-hand waving” today. Note rust on panel piping; adds artistic content. “Rusty corral and Cumulus humilis”; yours today only for $2,000.

Since there is STILL no rain indicated for the next 15 days in the models, just dry (for now) trough passages, I may have to discuss yesterday’s sprinkle again tomorrow. Thinking of a title even now: “That sprinkle; more insights on what happened.” Yeah, that should do it.

The End.