Cloud-maven – Page 57 – About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno

The trace

We had a trace yesterday in SH. There was not ONE but TWO periods of rain, the first at 1236 to 1237, and the second from 1240 to 1240:30, both from the same cloud, but likely from different turrets protruding above the base. The drops were very small, barely mm-size, with considerably horizontal separation between them. Likely were from a few ice crystals that rimed up, became soft hail, then melted and evaporated on the way down to those tiny 1-mm sizes.

Here’s the key to recording trace events: First of all, you have to “want it”; have to have the fire in your belly like I do, that a day in which a small amount of rain falls is not getting by you as a zero rain day. In effect, you have to have a linebacker’s mentality. Be out there when it might happen, park your car outside overnight after cleaning the front and back windows before nightfall. Dust on it is especially good.

Now for yesterday and what happened, presented in detail so that you can improve your trace measuring skill set:

SONY DSC — 12:17 PM. Cumulus congestus lined up to pass over Sutherland Heights. Have to be ready.

12:36 PM. Isolated drops falling, there's one over there, and I thought I felt one, arms extended. But cloud is slipping slightly to east of me! No shaft coming out! — 12:36 PM. Isolated drops falling, there’s one over there, and I thought I felt one, arms extended. But cloud is slipping slightly to east of me! No shaft coming out! But great looking cloud bottom. Will go into that collection.

12:35 PM. Just before first drops felt. — 12:40 PM. Another surge of little drops, can hear them on porch roof! Bottom not looking as generous as a couple of minutes ago.

———-

Now, for that smog bank that moved in during the afternoon….THAT was a horrible sight, and kind of ruined the late afternoon sky views. The deep blue seen in the first shot was replaced by this whitish, hazy look, lots of “crepsucular” rays, in fact the whole sky got a bit “suckulent”, to misspell another word with purpose…. Take a look:

Likely will have the same stuff today. Origin? Well, seems to be coming out of the southwest and Mexico, but also may be old southern Cal smog. Here’s the GOES aerosol optical depth (AOD) image for later yesterday afternoon, 3:15 PM.

GOES AOD for 3:15 PM. Be glad you're not in Bakersfield, CA! But note some smog over and to the SW of Tucson heading this way. — GOES AOD for 3:15 PM. Be glad you’re not in Bakersfield, CA! But note some smog over and to the SW of Tucson heading this way around low in central AZ. Colored regions denote smog; blue small amounts, orange and red, ugh, gimmee a handkerchief! Can’t measure AOD if too many clouds are present.

Today? Some smog, some pretty-but-dirty Cumulus clouds (ones with extra high droplet concentrations, likely darker bases than they really should have due to the “dirt” inside’em), and not much more. Maybe a Cumulonimbus off on the horizon somewhere.

Better late than never; night storms dump 1.42 inches on Sam Ridge!

If you were awakened last night by thunder, as I was, but then that bit disappointed that not a lot of rain fell, well it did, just not here. In three hours, in the epicenter of those storms, Samaniego Peak got a whopping 1.42 inches, by far the most around, bringing the 24 h total there to a magnificent 1.93 inches. Here in “The Heights”, we only got a tenth last night, with the 24 h total ending at 7 AM, of just 0.19 inches, thanks to about a tenth yesterday morning. You can see more precip data here from the Pima County ALERT gages, along with the other sites such as Rainlog.org and CoCoRahs.

The “tropical river” of moisture from the Tropics is shifting east, and soon we’ll be in the “dry wash” of the westerly flow from the Pacific, too soon really, with a very small chance of storms. Today is the last day of the larger ones, ones with a greater chance of landing on Catalina. After today, we’ll likely just see them off in the distance.

There were some fabulous scenes yesterday, even in the overcast morning rains, followed by those low Stratocumulus and Stratus fractus clouds lining the Catalinas. Here are a few, well, too many again:

7:56 AM. You may wonder why I am posting this shot. Well, its a sky we don't see often here, that dark, rainy look, Stratus fractus creeping along the Catalina Mountains. I thought it was pretty neat. Wouldn't if I still lived in SEA; would be same old same old as they say. But here! Fabulous. — 7:56 AM. You may wonder why I am posting this shot. Well, its a sky we don’t see often here, that dark, rainy look associated with Nimbostratus (the amorphous cloud above the darker ragged Altocumulus.Stratocumulus clouds in the center). Stratus fractus is creeping along the Catalina Mountains. I thought it was pretty neat scene. Wouldn’t if I still lived in SEA; would be same old same old as they say. But here in Catalina? Fabulous.

9:25 AM. While the little rain storm had ended, those low Stratocumulus (too bumpy to be Stratus) were a delight to see up against the mountains with the light playing on them as holes in the higher Altocumulus deck went by,

10:25 AM. Springtime for fungi. Our recent rains have triggered unusual life forms. Here, a large white disk has emerged from the soil just off ET *Equestrian Trail), encountered while walking the dog. — 10:25 AM. Springtime for fungi. Our recent rains have triggered unusual life forms, probably from Seattle. Here, a large white disk has emerged from the soil just off ET *Equestrian Trail), encountered while walking the dog (Laurie Anderson).

11:40 AM. Wasn't long before a bit of heating launched giant Cumulonimbus, though soft ones, not real powerful ones. Still, a gorgeous sight. — 11:40 AM. Wasn’t long before a bit of heating launched giant Cumulonimbus, though soft ones, not real powerful ones with a lot of lightning. Still, a gorgeous sight. Looking northwest, beyond Saddlebrooke.

12:10 PM. Windshift line marked by a line of Stratocumulus approaches Catalina. This did not seem good. There was no real response to it, just shallow clouds, and the clouds behind it seemed suppressed, suggesting drier air was going to move in. I wonder if you saw this line of clouds? — 12:10 PM. Windshift line marked by a line of Stratocumulus/Cumulus congestus (right) approaches Catalina. This did not seem good. There was no real response to it, just shallow clouds, and the clouds behind it seemed suppressed, suggesting drier air was going to move in. I wonder if you saw this line of clouds? Any cloud line like this should be viewed as one likely associated with a wind shift. It was also approaching pretty fast.

3:10 PM. After being in the gym for awhile, came out to see that drier air had indeed moved in, and these great looking Cumulus congestus clouds were going nowhere. From the "Not taken while driving" collection. I really like not taking pictures while driving. That would crazy to do. — 3:10 PM. After being in the gym for awhile, came out to see that drier air had indeed moved in, and these great looking Cumulus congestus clouds were going nowhere. From the “Not taken while driving” collection. I really like not taking pictures while driving. That would be a crazy thing to do.

4:09 PM. The Cumulus over the Cat Mountains continued to wither under the influence of drier air. Was getting pretty discouraged since little of the daytime rain predicted had occurred by this time.

In fact, the only precipitation I had seen since about 9 AM in the morning was by this cow. "Precipitating Cow", yours for $2,000. — In fact, the only precipitation I had seen since about 9 AM in the morning was by this cow (look closely). “Precipitating Cow”, yours for $2,000.

5:31 PM. Cute little cloud tries to grow up like his surrounding brother and sister clouds. What an effort! (Demonstrates the instability of the layer in which the Cumulus formed.)

6:30 PM. But hope arose again as a line of Cumulonimbus appeared on the horizon before sunset, and grew closer. Because there were several, you could tell it was something organized was yet to come; it was not just an isolated one or two. Note the pileus cap on the highest turret (between the lines) indicating a strong updraft.

6:54 PM. Unzoomed view of the approaching group of Cumulonimbus, our nighttime storms. The shadow radiating from the setting sun was due to a Cumulonimbus top not visible on the horizon at right. Indicative, too, of organization, something that might make it into the night, not just die away, were all the towering Cumulus lined up on the horizon to the left of the big cell in the center. Pretty darn spectacular scene I thought.

Precipitating cow

Wall of Voodoo

Nice lighting

Clouds were so-so yesterday, didn’t deliver the big punch as one U of AZ mod foretold (Samaniego Ridge and vicinity only got a tenth of inch or so compared with the 1-2 inches that was predicted), but, the lighting yesterday morning, oh, my, that lighting on the mountains and elsewhere as little breaks in the overcast Altocumulus/Stratocumulus deck zipped by, were beyond description. Lost control and began snapping photos like a turtle or toad surrounded by little flying somethings that they thought would be great to eat. Here are SOME:

For the day in review go to the U of AZ time lapse movie. Its really pretty interesting, and if you thought it was a dull and disappointing day, at least it will go by fast.

At least we did receive another 0.04 inches here in SH-Catalina over the past 24 h, though it fell at an excruciatingly low rate; didn’t think that little tipping bucket would ever tip for that ONE hundredth amount. Seemed like drops fell for hours before it did. BTW, the forever reminder: it wasn’t drizzle precip, but rain, very light

RAIN!

(This is my legacy; that when I am done, folks say; “You know, I knew that guy. I don’t remember a thing that he said except that drizzle isn’t a few drops here and there, but rather a thick, misty kind of precipitation that floats under your umbrella if there’s much wind. Comes from the coalisions-with-coalescence rain formation process, one that doesn’t require ice, though I don’t know why I would want to remember something like that.”)

Today….

Another fun-filled cloudy day with rain here and there. “Take Me to the River“, as David Byrne wrote, and was covered by the Songs of Science by Bill Nye et al (which I can’t find online, dang), the tropical one. Well, its here, that tropical one, passing right over head and so the POTENTIAL for big rains continues for another day or so. Lots of rain predicted twixt now and midnight by that U of AZ WRF-GFS mod–you can go here and check it out. Of course, it wasn’t so great yesterday, but they’re just too good most of the time to discard and so maybe today and tonight, the errors won’t be so great and we’ll pick up an inch or so hereabouts.

The End.

Boring but intersting day behind us

Well, it seems that the WP spell checker doesn’t work on titles. Intersting. Oh, well, “intersting” gives today’s cloud harangue a folksy, accessible aura I think.

So not much happened yesterday. Kind of dank with that mid-level Altocumulus overcast, a few sprinkles-its-not-drizzle¹ here and there most of the day. I noticed I didn’t take even 100 photos, a photographic measure of local sky boredom. Three hundred plus? Now that’s a really great day!

Here’s what we had, the first photo of the day just after 9 AM (a little slow off the mark due to boredom):

9:13 AM. Altocumius opacus, some light precip coming out beyond Pusch Ridge. But that big clearing, filled with huge Cumulus portent was a fine sight. — 9:13 AM. Altocumius opacus, with a lower patch of Stratocumulus with some light precip coming out beyond Pusch Ridge. But that big clearing on the horizon, filled with huge Cumulus portent was a fine sight.

9:30 AM. Going down Oracle toward Tucson, that gritty looking rain haze was apparent on Samaniego Ridge. People often don't realize how much we descend when going into Tucson from Catalina-its-not-Tucson, but I think this shot demonstrates that incline. — 9:30 AM. Going down Oracle toward Tucson, that gritty looking rain haze was apparent on Samaniego Ridge and on Ms. Lemmon. It was nice to see.

Was going down to the south part of Tucson, well, South Tucson, to look at a car for sale on Craig’s List. Since yesterday was so boring, will show shot of that car to break up the boredom to follow. The sellers wanted $3,000 for it. I thought it was a little high after I saw it up close. Looked like it had been sitting there awhile, maybe 10 years, too:

10:06 AM. Car for sale, $3,000. Maybe they meant pesos, or rupees. — 10:06 AM. Car for sale; $3,000. Maybe they meant pesos, or rupees. I deferred. Missed a lot of lack of action in Catalina, too, in the hours it took to go take a closer look down Tucson way. Real nice folks, though, were offering it. Cute story about how they met. He was from Bremerton, WA, called down to complain about some work she had done, and then decided to move to Arizona and next door to her! Gossip content always jacks up ratings and that’s what we’re into here. What would we do if we didn’t have titillating gossip? (This is a true story, BTW.)

12:32 PM. Altocumulus lenticularis, produced by an air bounce off the Catalinas, embedded in Altostratus — 12:32 PM. Altocumulus lenticularis clouds (hover clouds that don’t move), at left and at center above the dark tuft. The lenticular clouds were produced by an air bounce off the Catalinas. They formed at the base of an Altostratus layer. Other patchea of Altocumulus clouds are seen in the distance. The dark tuft in the foreground was first beginning of a Cumulus cloud near the Catalinas (Cu fractus), but it went nowhere.

4:18 PM. That Altocumulus lenticularis, still hanging on. — 4:18 PM. That Altocumulus lenticularis, still hanging on, though it has moved in position a bit.

For a terrific view of yesterday’s clouds and those lenticulars that recurred over and over again, to be redundant, go to the U of AZ time lapse movie for yesterday. It also demonstrates how breezy it was up there at cloud levels compared with our normal sluggish summer flow, and how complex behaving clouds are even when they appear dank and uninteresting.

Of course, we had a nice clearing, and some Cumulonimbus clouds arose in the distance toward the border during the mid and late afternoon. And as the sun went down, another thick patch of middle clouds started coming across the Catalinas with light rain, and with that, a rainbow appeared. Quite nice.

6:30 PM. A rainbow briefly appeared as another patch of lightly raining As/Ac clouds approached producing a segment of a rainbow just beyond the Catalinas. — 6:30 PM. In case you missed it again, a rainbow briefly appeared as another patch of lightly raining As/Ac clouds approached

Seems like a nice place to quit inserting photos.

Today?

Very light rain over the past 2 hours, and so we’ve accumulated another 0.03 inches on top of the 0.42 inches yesterday. U of AZ mod run from 11 PM last night seems to think we’re in for a pretty good rain day today. Seems to be predicting something around 1.5-2 inches on Samaniego Ridge before midnight (mod run not done yet, either!) Well, these forecasts tend to run on the high side, but still, this could be a fabulous day here in the tropical river we’re in! Charging camera batteries now….

BTW, flow is now from the south, and so you’ll want to be looking toward Pusch Ridge for “incomings.”

The End.

————————

¹Another reminder about the difference between “drizzle” and rain. You must know this. Sprinkles isn’t drizzle!

Stormy weather; 0.42 inches so far

Three thunderstorms with rain here, one overnight, have dumped 0.42 inches here in SH (Sutherland Heights) More is virtually certain. 1.18 inches fell at Horseshoe Bend Road in Saddlebrooke. More reports here and here and here and here, to name a few. Can’t wait for daylight to see how the desert looks.

What an interesting day, beginning with the odd scene of an Altocumulus lenticularis overhead, telling us the wind was substantial and from the east or southeast. Usually you see this cloud in the cool half of the year on the other side of the Catalinas, but there it was, filled with mystery and lightning!

1:54 PM. From the cloud bottoms collection, this. Just about everyone fulfilled its promise by having a — 1:54 PM. From the cloud bottoms collection, a photopgraphic niche of mine, this overhead view just before Saddlebrooke got dumped on. Just about every wide cloud bottom fulfilled its promise by releasing rain yesterday, even some pretty small ones. I thought this shot was exceptional. Price, $1,500. Would look great on somebody’s wall; great texture!

2:06 PM, just three minutes later! Saddlebrooke about to be pounded. Look for golf balls in the CDO.

6:06 PM. Then after a long break in the action, kind of like halftime at a fubball game, those magnificent Cumulus began to reform, climb up once again to levels where they could form ice and rain. I thought this sight was reel perty. Took many photos of the same thing, that's the way it is with photographers. — 6:06 PM. Then after a long break in the action, kind of like halftime at a fubball game, those magnificent Cumulus began to reform, climb up once again to levels where they could form ice and rain. I thought this sight was reel perty. Took many photos of the same thing, that’s the way it is with photographers.

“Little Swirl”, a cyclonic eddy really, but could be somebody’s name, too, to SE moving NW and over us this morning: Look here. Will help keep showers going today, but also check with the real experts. Must quit here as time expires for big bandwidth flow.

Mediocre clouds followed by a brilliant sunset

In case you missed it, this eye-candy from last evening as a crepuscular ray highlight some lower Altocumulus below the main layer:

6:42 PM. Was gasping after sprinting up hill in an obsessive-compulsive pulse to get this shot. But it was worth it.

Now, for the rest of the day. The Cumulus clouds with tops flattening into Stratocumulus were a bit disappointing, their tops, in a few places, did reach the level where ice would form in them and virga and a few light rainshowers fell out. Remember, gotta have ice to have precip is Arizona, mostly.

1:21 PM. Larger patch of Cumulus, spreading out due to a "stable layer" has reached upward to begin forming some ice. That fallout of ice is causing the base to look a little too smooth. If you can detect this, you have reached the pinnacle of cloud maven-ness. — 1:21 PM. Larger patch of Cumulus, spreading out due to a “stable layer” has reached upward to begin forming some ice. That fallout of ice is causing the base to look a little too smooth. If you can detect this, you have reached the pinnacle of cloud maven-ness. Its just beginning to come out, very hard to detect at this point, more obvious in minutes. Even I wasn’t sure at this point, but hedged an opinion about it to myself.

1:42 PM. Same patch trailing ice, though not much. Still a difficult proposition to see it. — 1:42 PM. Same patch trailing ice, though barely. Still a difficult proposition to see it. Its just SLIGHTLY frizzy/fuzzy at the bottom, a look due to low concentrations of single crystals and a few snowflakes.

2:08 PM. Now the presence of ice is obvious. You have a wonderful itty-bitty rain shaft reaching the ground, and an ice veil around the edges of this cloud. Even a little baby could see that there was ice now. — 2:08 PM. Now the presence of ice is obvious. You have a wonderful itty-bitty rain shaft reaching the ground, and an ice veil around the edges (upper left) of this cloud. Even a little baby could see that there was ice now. But as little and as long as it took to form and fallout, you would guess that the top was marginally cold for ice formation, a superb scenario for research aircraft. From last evening’s TUS sounding, looks like they were barely ascending past the -10 C (14 F) level, maybe to -12 C to -13 C here in those tops that overshot a little inversion at -8 C. Those flat-topped Altocumulus clouds that rolled in during the evening as the sun set had tops around -8 C, just a little too warm for ice to form in them.

3:27 PM. But that TUS sounding was not indicative of the air just a 100 or so miles south of us where large and deep Cumulonimbus arose. Can you see a Cb calvus top in this photo? It was pretty exciting to think that air capable of producing large storms was so close after it looked for awhile like a longish dry spell. The moisture was returning faster than models foretold a few days ago.

3:26 PM. — 3:27 PM Zoomed view of distant Cumulonimbus calvus top, far easier to see without the smog of the day before!

Today, the inversion is gone, and dewpoints are increasing all over southern Arizona as we start into a real tropical push. So chances of rain here in Catalina are zooming upward. Should be some nice “Cbs” around.

Tropical storm Lorena is headed toward the tip of Baja and its remnants will come into southern California and Arizona over the next few days. Hang on for some potential mighty rains, something to bring our summer rain season totals to more respectable levels here in Catalina. Very excited, as are all local weather folk!

Also, no end to summer rain season yet appearing in mod run extending out for two weeks (from last evening’s global data crunch). Still seems to hang on, for the most part, through the 20th of September. Excellent.

Canadian dreams

Note: Images did not show up when posted yet are present in draft; first time for this happenstance in WP.

This just in, from last night’s global GEM model run by The Canadians. Using a magnifying glass, you can see that these panels show a tropical storm (now only known as Tropical Depression 12-E) moving into Arizona on the evening of September 9th (the panel with all the red coloring). Hmmm. Something to dream about, a final big greening rain; well, maybe just holding off the crispy period of our vegetation following the summer rains. In any event, the tropical river should be back over us, even if it misses, bringing some more of that summer rain.

The USA! “WRF-GFS” model have no such storm, so there’s no point in showing that model output, though it does get real showery here before and on the 9th. That would be good, too, though not AS GOOD.

Dreaming of what might come will help us get through the mini-drought and several day hot spell we’re now in I think. Today is supposed to be pretty much like yesterday, capped small Cumulus clouds, too small to form ice and precip.

——————————

Yesterday you probably thought there were no Cumulonimbus clouds in sight. Maybe the haze and smoke were too much for you, and looking at local Cumulus clouds with not the slightest inclination to be more than “mediocris”, you gave up looking.

No Cumulonimbus sightings in your weather diary?

I feel sad that you didn’t see them, and you really didn’t need the telescope at the Stewart Observatory, but almost. The smoke and haze, which made the sky whitish, made it a challenge, maybe like seeing a spotted owl in Eugene, OR. Still, they were there. Here’s the physical evidence:

3:43 PM. Hiding through the haze, a Cumulonimbus calvus turrets. Still can’t see ’em?

Same zoomed scene with helpful arrowing.

Where’s all the damn haze and smoke coming from after our stupendously clear days, ironically, during our high humidity and wet spell?

Mexico, after the the air mass has poured across there from Texas. In case you still don’t believe me, take this from ARL:

Back trajectory of the air at 4,000 meters above sea level over Tuscon at 5 PM yesterday. — A 72 hour back trajectory of the air at 4,000 meters above sea level over Tuscon at 5 PM yesterday. Looks like it started out as a mid-level “long range” transport since this suggests that the haze was already up above 5000 meters three days ago.

Thunder-a-plenty, but only a trace

A great immediate sign yesterday of the later cloudscape, if you were outside and not working in a room with no windows, was the early Cumulus rising off Ms. Lemmon. Some places got half inch to an inch, but only a trace fell here amid hours of thunder. Here’s the day:

9:29 AM. It would have been good for you to have pointed out the early riser, then told your neighbor, I think its going to rain today, by Leonard Cohen; "Broken windows and empty hallways, — 9:29 AM. It would have been good for you to have pointed out the early riser, then told your neighbor, maybe breaking out in song, “I think its going to rain today”, by Randy Newman; “Broken windows and empty hallways, pale dead moon in a sky streaked with gray.” Well, pf course, you know this song. Well, if you’re friend hasn’t shot himself after you’ve finished that sad song, you might also have added, “there could be a lotta thunder with that rain, too.” Well, there’s always a lot of thunder here in the summer, but it sounds prophetic to add that.

11:18 AM. First thunder on the Lemmon! Was pretty pumped as anvil overhang overspread me and The Heights. Was thinking rain moving off the mountain this time! — 11:18 AM. First thunder on The Lemmon! Was pretty pumped as anvil overhang overspread me and The Heights. Was thinking “rain moving off the mountain this time!” And little itty bitty spritzes did, over and over again all day and thunder crashed and boomed around for hours. The result was one of the heaviest traces of rain ever I think to Sutherland Heights. Public service message: Overhangs like this can spit out a spark down to the ground, WAY out ahead of the rain area, visible on the top of Ms. Lemmon. Its not good to be out under it standing on a knob, pretty much the highest point around, taking pictures like this. I went out as soon as I heard thunder; would never just go out without knowing where it was in the charging cycle. Still, you probably shouldn’t even do that since that charging cycle can rev up, too. Silly me.

11:50 AM. Anvil overhang from The Lemmon with new Cumulus piling up north of Saddlebrooke, as they often do. This indicated storms were going to also form before long over the lower terrain. Sometimes, as you know, they can't. — 11:50 AM. Anvil overhang from The Lemmon with new Cumulus piling up north of Saddlebrooke, as they often do. This indicated storms were going to also form before long over the lower terrain. Sometimes, as you know, they can’t. When they do this, it means we have a chance to get a core, as does everyone out in the hotter lower elevations.

1:26 PM. A real beauty north of the Gap. The darkening blue sky that goes with autumn really brings out the contrast between these immaculate white tops of a.....Cumulonimbus calvus ("bald") on its way to the fibrous "capilatus" stage (when the ice phase up there is clearly evident). — 1:26 PM. A real beauty north of the Gap. The darkening blue sky that goes with autumn really brings out the contrast between these immaculate white tops of a…..Cumulonimbus calvus (“bald”) on its way to the fibrous “capilatus” stage (when the ice phase up there is clearly evident). It may have been this one or the next one that dumped a half an inch around Oracle town.

3:07 PM. If you look carefully around this power pole, you can see that the heavy rains, indeed, got out into the lowlands. I hope I have made my point about poles and wires. They have no business being above ground. — 3:07 PM. If you look carefully around this TEP Co power pole, you can see that heavy rains, indeed, got out into the lowlands. I hope I have made my point about poles and wires. They have no business being above ground in the 21st Century.

3:12 PM. A little mammatus showed up, too, maybe from a collapsing, "overshooting" top. — 3:12 PM. A little mammatus showed up, too, maybe from a collapsing, “overshooting” top upwind.

6:47 PM. Overhead wires and just a trace of rain are forgotten about as this luscious sunset unfolded down below where i had to walk to avoid the overhead wires. — 6:47 PM. Overhead wires and just a trace of rain are forgotten about as this luscious sunset unfolded down below where i had to walk to avoid the overhead wires being in the photo.

Looks like a similar day today, just eye-balling the maps and stuff, clouds piling up on The Lemmon, drifting NW over Sutherland Heights and Catalina, chance of thunder, some sprinkles or light showers. However, drier air is filtering in from the east as I type, meaning cloud bases will likely be higher than yesterday, and we probably won’t see such an early start to Cumulus forming on Ms. Lemmon as we did yesterday. And not as much cloud cover.

Supposed to dry out tomorrow and Friday further but then moisten up again on football viewing days, Saturday and Sunday as a tropical storm/depression works it way up the Baja coast. Could be a great weekend.

Below, a remarkable storm report from yesterday from around the Prescott area, brought to my attention by climate folk hero, Mark Albright at the U of WA:

504 PM MST TUE SEP 03 2013

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

0425 PM FLASH FLOOD 4 NNW PRESCOTT 34.63N 112.48W
09/03/2013 YAVAPAI AZ TRAINED SPOTTER

TWO INCHES RAIN FELL IN A HALF HOUR…WILLIAMSON VALLEY
ROAD JUST NORTH OF PRESCOTT…WATER FOUR FEET DEEP IN
WASH…CARS AND LOGS CARRIED OFF ROADS

Crazy over pileus

Lost control for awhile yesterday evening at sunset as pretty little pileus caps formed repeatedly on top of new Cumulus congestus/Cumulonimbus turrets to the west. It like an entomologist seeing a spotted owl, or some other rare bird like that. You don’t see pileus caps that often, and when you do, you’d better have your camera ready because they only last seconds. Nice sunset color along with them, too. Some nice lightning over that way later, too.

If you were in a research aircraft and wanted to find the most liquid water around at a particular flight level, a pileus cap on a Cumulus turret at that level is a good sign that that’s where it will be compared to other clouds. But don’t sample too close to cloud top, maybe 100 m below since dry, ambient air is being mixed into the extreme top and you MIGHT not measure the most liquid water there, especially if the top looks a little “frizzy.” . Its fun to see how much you can hit with an airplane; see what the instruments do.

The rest of the day was very nice before this pretty much replicated the day before in virtually every detail; several Cumulonimbus clouds arose on Ms. Lemmon beginning in mid-afternoon, anvils trailed over Oro Valley, and there were again a number of distant Cumulonimbus clouds to the NW-NE scattered over the high terrain way up that way. There were also Cumulonimbus far to the S-SW toward Mexico, as well as an active cluster to the west at sunset that generated so many pileus clouds. Here is your cloud diary day in photos:

5:58 PM. Grouping of Cumuloni,bus and Cumulus congestus clouds distant west, ones with repeated pileus caps as new turrets surged upward through a thin moist layer, also shoved up due to the approaching rising air in the turret.

6:56 PM. Yet another pileus cap formed, but this time, is above the top of the surging Cumulonimbus calvus (its got rain coming out of it) top. — 6:56 PM. Yet another pileus cap formed, but this time, is above the top of the surging Cumulonimbus calvus top. (Its got rain coming out of it, so its that bit better to call it that instead of just a Cumulus congestus.)

The clouds prior to the pileus eruptions were these ones:

5:19 PM. Pretty much all over here, just a big anvil as bottom got rained out with no more surges of Cumulus to keep feeding it. — 5:19 PM. Pretty much all over here, just a big anvil as bottom got rained out with no more good surges of Cumulus to keep feeding it. Just getting too cool up there.

Want to get one more thing in here, in case you haven’t paid attention to all the rain that’s been falling in Arizona, particularly in the NW part, SE CA, and southern Nevada. They are having a spell that is just incredible. Here, from WSI Intellicast, the 7-day rainfall totals for the US, which highlights how well those areas are doing compared to the rest of the county even. This is an amazing graphic, and so pleasing since all this rain in the Southwest has been falling on very drought-impacted areas.

The seven day, radar-derived precipitation totals for the US. Mountains, of course, interfere with radar beams that do this, and so in mountainous regions these estimates are likely too low, or can be missing altogether.

Summer rain season set to sputter along today and for the foreseeable future. Looks like there will be a few more thunderheads around today compared to yesterday, a bit more instability today, too, this from a 2 min look at model outputs as choke time approaches. If you want a good forecast, you should see Bob’s writeup. I like Bob. Plus, he’s a stupendous expert on convection!

Isolated, but “volcanic”

Forgot the nice sunrise and another faint rainbow, two mornings in a row! In case you missed them, again, here they are:

While yesterday’s Cumulonimbus clouds were sparse, their “overshooting” tops told you that they had pretty violent updrafts in them, ones that carried the top of the cloud past the tropopause (the boundary where the decline in temperature as you go higher stops). Above the tropopause sits the stratosphere, normally cloud-free and extremely dry.

These “overshooting” tops are due to inertia generated by the strongest updrafts in the cloud below them, they end up being much COLDER than the surrounding air in the stratosphere because the air is still expanding and cooling as the cloud punches through the tropopause. Like stones in water, they plummet back down quickly as they drift away from the root updraft. The worst volcanoes, like El Chicón in the early 1980s and, of course, Pinatubo in 1991, do this, too, and to a lesser degree these overshooting tops also inject aerosols and moisture into the stratosphere. These tops are usually easily recognized as a bulb-looking, whiter top above the flat anvil, the anvil representing cloud top ice that has been stopped by the tropopause barrier and has spread out.

Some examples:

1:10 PM. Violent looking Cb with an overshooting top. There were many of these yesterday, regrettably so far away you couldn't even see the rain shaft! Boohoo. — 1:10 PM. Violent looking Cb with an overshooting top, one that punches through a flatter anvil cloud. There were many of these yesterday, regrettably so far away you couldn’t even see the rain shaft! Boohoo. Here, looking SSW from Catalina, range about 50 miles or so.

2:51 PM. I thought this cluster looked especially "volcanic" with how tight the Cumulus tops were in the foreground. When the updrafts are strong from the base on up, you have a lot of aerosol particles taking part in the condensation melee, cloud droplet concentrations are extremely high, the clouds are extremely dense inside, might not be able to see the wingtip of your aircraft. For this reason they look like granite on the outside. When ice forms, such as in the higher tops, the concentrations are less and the cloud "softens" in appearance. — 2:51 PM. I thought this cluster looked especially “volcanic” with how tight the Cumulus tops were in the foreground. When the updrafts are strong from the base on up, you have a lot of aerosol particles taking part in the condensation melee, cloud droplet concentrations are extremely high, the clouds are extremely dense inside, might not be able to see the wingtip of your aircraft. For this reason they look like granite on the outside (center). When ice forms, such as in the higher tops, the concentrations are less and the cloud “softens” in appearance (highest top, left of center), one that appears to have punched through a flatter anvil cloud.

2:56 PM. Many Rim Cbs also had overshooting tops. In our worst storms, with frequent cloud-to-ground lightning and blinding rain, you can pretty well be sure that you're under one, or close to it. — 2:56 PM. Many Rim Cbs also had overshooting tops. In our worst storms, with frequent cloud-to-ground lightning and blinding rain, you can pretty well be sure that you’re under one, or close to it.

1:38 PM. Mt. Lemmon did join the Cumulonimbus producing fray in the distant mountains around us, but they were about a magnitude smaller than the ones in the distance, and, as you saw, could not leave the high terrain. — 1:38 PM. Mt. Lemmon did join the Cumulonimbus producing fray in the distant mountains around us, but they were about a magnitude smaller than the ones in the distance, and, as you saw, the several that formed could not leave the high terrain.

Seems we have a day similar to yesterday ahead for today, but the models suggest an uptick in activity tomorrow. When the thunderheads are more isolated, they are more photogenic I would have to say, especially against the backdrop of the darker blue skies we have now. And with no haze around, something that often can accompany higher humidities such as we have had over the past week or two, our cloudscapes are especially pretty I think.

The End.