Cumulus clouds – Page 27

Lemmon bloom

Thunderstorms in the distance crept toward the Catalinas late in the day, and after sunset, an approaching, but thinning anvil of a dead Cumulonimbus cloud (no updrafts remaining to feed the anvil) produced this beauty. With the death of this prospect, any hope of rain moving in here later in the evening went six feet under as well.

The anvil below looks fairly close, but if you go to the U of A time lapse, this anvil comes onto the field of view at about 7:40 PM, and you can get an idea of how much farther the anvil below had to go to be above the Cat Mountains.

For the second day in a row there were virtually no Cumulus clouds over our Catalina mountains, a real disappointment. But, undaunted, Mr. Cloud Maven person will anticipate Cumulus clouds over the Catalinas once again today, following in the same wrong footsteps of the past two days, and will again foretell that these will be ones that will rise high enough to “glaciate”, that is, have their tops convert from liquid droplets to ice crystals.

The result of this “glaciation” process is something coming out the bottom of the cloud, a dense shaft of precip, as a Cumulus cloud transforms itself into a Cumulonimbus one.

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Science Story: This is always an exciting sight and a process that Mr. Cloud Maven person (MCMP) spent some 25 odd years studying with a highly instrumented aircraft at the University of Washington but couldn’t quite figure out how it happened. In fact, MCMP (with his lab chief co-author) were criticized royally (i.e., Blyth and Latham 1998) for what they did report over the years (“royally”; they were two British guys, but working in the US). We “Reply” to their comments in quite substantial fashion in the same issue (Reply to Blyth and Latham)!

BTW, real scientists, like Alan Blyth, are still working on this problem; how clouds glaciate. Its pretty amazing when you think of it. These days the Japanese (asteroid dust Science-2011) can send a spacescraft to an asteroid named, Itokawa, land on it, pick up some dust grains, and bring them back, a process taking more than 10 years, but we really don’t know completely how ice forms in a cloud!

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Back to the local scene:

once again we have our high surface dewpoints, in the upper 50s (58 F here in Catalina) and even 62 F now at Douglas. So the bottom of our atmosphere is OK for Cumulus. And once again, we have an overcast of mid-level Altocumulus clouds. A problem yesterday was the extreme dryness above that surface moist layer, and below the Altocumulus one, a shallow moist layer that was completely obliterated after the sun came up and the dry one and razor-thin moist one mixed together. Its not so dry today above the low humid layer today, and so Cumulonimbus clouds should be able to develop in the area.

Besides the models told me so. Have been a little sloppy and a little, well, arrogant, about reading the early morning sky absent more information.

Here’s today’s TUS sounding, from the Wyoming Cowboys, so you can see for yourself.

The End, unless I find out I am going to be wrong again when more data comes in a couple of hours.

68 F dewpoint in Catalina now; 0.31 inches overnight

68 F dewpoint at TUS, too. With this kind of dampness, it should be an exciting day with clouds topping the Catalinas, and you know when that happens, its another sign of really heavy rain in the area. In fact, we have a little strip of Stratus fractus along the base of the Catalina’s now (5:29 AM).

Let’s go to the National Weather Service’s web page and see if they are excited about today… Yes! They are pumped, with “green” shading designating those areas of southeast Arizona in a NWS flash flood watch!

Here’s the 4 AM map below, courtesy of our University of AZ Wildcats National NCAA Baseball Champions Weather Department. What a great final game that was! (You can get their latest map here.)

After a mostly disappointing day, an unusual summer day in which there were no clouds being launched off the top of Mt. Sara Lemmon, and temperatures were unusually “cool”, there was finally a strong, whitish brightening of the sky to the east, with darkening to the northeast beyond Charoleau Gap, as the sun slid below the horizon.

And if you were looking at the Weather Underground (now having been absorbed by The Weather Channel in some kind of capitalistic power grab) web page for the Catalina area, you saw that the brightening beyond the Catalina Mountains yesterday evening was due to the anvils of an approaching complex of Cumulonimbus clouds. But as we know, they don’t always make it after dark coming from the east, only on some days. They often fade away, or only produce sprinkles.

It began to rain pretty hard right at 9:30 PM, but there had been no lightning preceding it. I was surprised at how hard it was initially raining, thinking earlier that the rain was going to be old stratiform rain from dead Cumulonimbus remains, very steady and light, maybe adding up to just few hundredths. Then “BLAM” this brilliant bolt nearby and two huge booms of thunder setting off a car alarm near us. How great that was! Rain continued to fall until about 2:30 AM. That lack of lightning suggests the rain producing cell was building right over us, finally climbing to heights and with updrafts strong enough to produce the first lightning. Sprinkling again now (for a couple of minutes) from Altocumulus opacus clouds… Very unusual to have morning rain here as you know.

You can get the regional values of rain here from the Pima County Alert gage network and also here from the U of A’s rain measuring network. Three Alert locations had over an inch, and many more in the U of A network! What a great start to the summer rain season!

Here’s a reprise of yesterday’s clouds starting with mid-afternoon and the remarkable absence of Cumulus boiling off the Catalinas. Instead, small Cumulus (“humilis”) were scattered helter skelter around the area as though there were no mountains.

Below, “the brightening” as Stephen King might put it, showing that deep clouds were around, and they were approaching from the east. The anvils, well above 30,000 feet, are still in full sunlight, and the sun is shining through the thin, probably haze-free air up there. Its undiminished light remains white when striking those cloud tops, not having had the shorter wavelengths scattered away by aerosols (until the sun subsides farther below the horizon).

Yesterday’s cloud movie .

Late bloomers and a dry day; but plentiful rains dead ahead

Here’s a brief reprise of yesterday in photos. Expect a similar day today, late rising Cu over the Catalinas, isolated Cumulonimbus off on the horizon, probably NW-NE over the Mogollon Rim, and to the distant SE-S. None are expected to make it here.

4:02 PM. Really haven’t done much, though some turrets poked up to the ice-forming level. Arrows show some ice falling out of an old, evaporating turret.

4:03 PM. Massive anvil appears over the horizon to the SE-S giving hope something could still happen.

5:52 PM. Getting closer!

7:16 PM. Rain complex stays to the S-SW, but provides a nice summer scene with occasional lightning.

7:37 PM. Cumulonimbus capillatus incus (one with an anvil) punctuates the sunset. Somebody got dumped on out there.

Don’t forget to go to the movies to re-live yesterday here, courtesy of our University of Arizona Wildcats.

The rain ahead

One of the great model forecasts of our time came out yesterday from the 12Z global data, and has been pretty much replicated in its results from the new data that came in yesterday at 00Z. These runs have had plentiful rains in SE AZ for just about every day after our little hot dry spell, and both of those US runs with all that rain ahead are supported by model runs by the Canadians using their brand of the Euro model. Here’s the US full run from last night, whilst the Canadian run can be found here.

What’s intriguing is that a tropical wave, sometimes called an “inverted trough” because its upside down compared to our winter troughs, is foretold to move into the State about the 4th of July. An inverted trough would bring extra organization and clustering of Cumulonimbus complexes, which means bigger areas of rain, often accompanied by a large stratiform rain shield that produces hours of rain. It is also true that these can be our most damaging storms.

OK, this big event is “out there”, and you know that this blog is going to jump on the wetter side of the model forecasts. Still, its pretty darn exciting to think of days of scattered showers beginning in early July, and maybe a real drencher just ahead around th 4-5th. The best part is that even if that doesn’t happen, we are embedded in a flow pattern that would keep up that a hopeful possibility of rain day after day, into mid-July.

Early to rise

These small fluffs of Cumulus clouds above Ms. Mt. Sara Lemmon, were the first indications that something good, and very different from the previous two days was going to happen yesterday. These clouds appeared no less than 4 h earlier in the day (between 9 and 10 AM yesterday) than those first Cumulus on top of the Catalinas on the previous two days.

The correct emotional response due to this early rising for cloud maven juniors and doscents out there should have been excitement and anticipation; that some big boys with long names (Cumulonimbus capillatus incus) were likely going to be around later in the afternoon and evening hours. No weather maps needed! See AZ Star for confirmation.

While we didn’t get a big dump right here in Catalina, we did at least get a dust-coagulating 0.02 inches. Here are the totals ending at 24 h from around the region from the Pima County Alert gages. The most hereabouts was at the Santa Cruz River at Ina Road with 0.59 inches, with that storm shown in the photo at 4:25 PM below.

Today, with dewpoints once again being in the upper 50s, it should be the case that we see these early precursor clouds on top of Mt. Lemmon, and they will once again lead to the conclusion of a satisfying day of thunder and intense rainshafts, driven by 100 F plus temperatures. It peaked at 106 F here yesterday in Catalina, and it was fairly cloudy when that temperature was recorded! Pretty remarkable.

Here’s your NWS computer generated forecast for Catalina, foretelling similar temperatures for today.

Here are some later shots of those great clouds, and if you want the whole nine yards, go to the U of A time lapse movie here. There’s a lot of rotation at the bottom of some clouds 1:03 before the movie finishes, and an indication of a rope-like funnel cloud, not too surprising given the instability of yesterday.

DSCN1915 — 4:23 PM. Eventually of those Cumulus congestus clouds reached ice-forming heights and produced our little 2 hundredths shower. By the time it reached Saddlebrooke, it had a visible shaft.

DSCN1919 — 4:25 PM: While our little shower passed by, Marana and vicinity were getting the real thing in dumps of more than half an inch.

DSCN1924 — 5:18 PM. Ditto to the NW where heavy rainshafts in this complex created a “haboob” that affected Casa Grande.

Maybe today, with plenty of clouds and heat, it will be our day to get the big dump and wash the dust off our desert plants.

The End.

Model trickeration, Dark Bluster, =s no rain!

You can see what didn’t happen here in the U of A time lapse movie.

I got pretty excited when the U of A Weather Department issued a special report yesterday morning on what the Beo Wolf cluster had come up with in terms of yesterday and today’s weather. These kind of special, technical reports, ones that only I can read, not general people, except in the pictures and everybody can read those and can comprehend, are only issued during the best (worst storm) monsoon days. So, it was VERY EXCITING for me to get in this special post in an e-mail. The many model runs had some great thunderstorms and wind building up to the S and SE of us and roaring in across the Oro Valley-Catalina urban complex during the late afternoon and evening. I was pumped. SOMETHING was going to happen!

And, just as the models were thinking, “anvilation” (first photo) began to appear to the south through soiuthwest by late afternoon before the AZCats won the national NCAA Division I baseball title. Sadly, that complex died out before getting here.

Then, over the Cat Mountains, things began to look more promising just before sunset (2nd shot).Cloud bases began looking more solid, not broken up into dark and light patches, and that solidity suggests an significant updraft over a wide area. I thought, “Here it comes!”, since those dark bases were moving off the Catalinas and toward us, possibly pushed by an outflow wind on the other side. This kind of thing, as you know, happens all the time here.

But no, those bases fell apart, they were merely a phenomenon called “Dark Bluster” which nobody really understands, and the only thing that happened from those clouds was a light rainshower over by San Manuel I think, one that produced a weak rainbow (3rd shot).

Oh, well, at least the evening ended with a nice sunset and a national title.

Today?

Hit and miss showers/thunderstorms likely in the afternoon and evening hours again. Nobody knows exactly where they will be so you’ll have to be watching. Actually this is a pretty good deal for later June, often with no chances of rain at all.

Update at 9:17 AM: Cumulus forming over the Catalinas! This is about 4 h ahead of the past two days. Is a darn good sign of more showers/thunderstorms today.

The End.

Two thunderstorms, but no rain here

A thunderstorm is in progress when you can hear thunder. Yesterday, beginning at 1:20 PM, we were having a thunderstorm in Catalina due to those modest Cumulonimbus clouds on top of the Catalinas. Here are those clouds, ones that streamed northwestward and died. This first photo of an isolated, flat cloud is the remains of what was a bulging Cumulus congestus turret that sprouted over Mt. Lemmon. It was of interest because at this time the tallest sprouts were just reaching the point where ice would form at noon to 1 PM yesterday. Its really unusual to see a marginal ice-producing turret like this dead one in the first shot. Such a cloud is of great interest to researchers studying the characteristics of ice formation since normally turrets ascend quickly through this initial ice-forming level to much lower temperatures, and the onset of ice temperature has to be estimated.

The rainshafts from these Catalina clouds were transparent (“Code 1”) the whole time they were producing, indicative of not much rain having fallen from them.

You can go here to the Pima County Alert site to see the rain totals hereabouts and in Tucson overall. CDO Wash at Rancho Solano (just NE of Saddlebrooke) got the most, 0.43 inches, due to a cell that developed later and is shown below.

This same Cumulonimbus can be seen at the very left edge of the view on the great U of AZ time lapse movie for yesterday here.

As the day starts, you can also see the waves in the atmosphere rippling through those Altocumulus/Ciirrocumulus clouds we had in the morning. Fascinating.

The next event was caused by the rush of winds from a strong cell near Marana that sent rain-cooled air pushing north into Oro Valley. That push of air gave a lift and a life to a developing Cumulus over Saddlebrooke just north of us, and before long, out dropped the load of rain, with occasional thunder with it, too. Here’s the “trigger cell” SW of Catalina with its rainshaft at the max which sent that rush of wind that in turn, pushed up the Cumulus over Saddlebrooke.

The full sequence of that Saddlebrooke cell is shown below.

Not a bad day yesterday–two thunderstorms in one day is always good–but less productive than hoped for here, always the case if there is less than an inch.

What’s ahead?

As you can probably feel, the humidity is still high. Dewpoints here are again in the upper 50s, quite juicy for AZ and that means another day of these sorts of clouds. Yay! I love photographing the bottoms of clouds, ones that are going to deposit a load, but before there is any sign of it coming out. And we will all have a chance to do that again today.

An extraordinary June 16th

Not only did Tucson set a daily record for rain on June 16th with 0.29 inches, breaking the old record of 0.20 inches that fell in 1918 (!), but here in Catalina, the 0.11 inches was the first measurable rain on June 16th in the 35-year combined record maintained at Our Garden, and then here for the past few years.

It was only the second day with measurable rain in Catalina since mid-April, and that prior rain was only a paltry 0.01 inches that fell in mid-May.

Regional rainfall totals for yesterday’s magnificent day can be found here, courtesy of the Pima County Flood Control District. Two sites in the Catalina Mountains got hit hard, with 0.94 inches at Pig Spring, and a whopping 1.54 inches at CDO at Coronado Camp. Those two gages are close to one another near the top of the CDO watershed. Here is a map having those locations. You can also get 24 h rain totals, ending at 7 AM today, from the U of A network here.

The best part, though, may have been those desert aromas that spring out of the desert when it rains, and that cool air that rushed around Catalina yesterday afternoon and evening. Makes you happy to be alive. However, those two close lightning strikes were somewhat unsettling when you’re running around outside with a camera..

The drop in temperature as the rain hit was stupefying, about 35 degrees, from 100 F to 65 F!

Here are some photos, since I am still alive, the first ones of the Altocumulus perlucidus clouds that were mutating into Cirrus uncinus, a bit of an oddity. The TUS sounding indicates that these droplet Altocumulus clouds were extremely cold, -30 C (-22 F). And their presence was another live demonstration about how odd ice formation is in the atmosphere, still not completely understood.

By late morning the Cumulus were sprouting over the Catalinas, and the Altocumulus/Cirrus were gone. Those Cumulus clouds were a great sight since the models had very little rain indicated, and these were fattening up nicely suggesting those models might not have gotten “the scene” for yesterday right; there was more hope for rain after all.

The weather ahead

The next chance for rain, the best one I could find, of course, is next Friday and Saturday afternoons. For Friday afternoon, this, from the U of WA’s model. The lightly colored, filled in areas represent rain.

Looking for just Cumulus today, maybe a very isolated Cumulonimbus cloud.

Dusty cool snap at hand

In MINUTES, the temperature will head downward as our long foretold (remember the spaghetti plots?) , “dusty cool snap” finally arrives. This time, from Intellicast, you can see below the blob coming, that blob of much lower temperatures with an epicenter at Las Vegas. Unfortunately, there are few clouds with this system, oh, maybe enough for a scruff over the Catalina’s a little later this morning and in the afternoon, Cumulis humilis, that sort of thing, and THEN we’ll get some nice cloud shadows on the mountains for awhile.

If you have a barometer, though, you will get to enjoy the “pressure check”, that sudden, sharp rise in pressure as the air over the barometer gets cooler and denser, mashes down on it more as the cold front goes by! You could be informing your neighbors about it. (Actually, “on further review”, with the temperature in descent now (5:18 AM), and barometer on the rise, I think the cold front has gone by already. )

BTW, while its windy here in Catalina right now, down in Tucson, they’re only reporting 7 knots, no gusts. This is kind of usual for this situation for us to get the brunt of the winds funneling up the Oro Valley while TUS is protected for the time being.

Still enough wind/pressure gradients around for dust today, but those gusty winds should really be gone by tonight and tomorrow in Catalina as that deep low, still in the Great Basin fades. See below for a neat looking weather map from where else, the University of Washington. In case you want to see more maps, go here.

Feels great to be in the circulation of a big low, that one centered in Utah right now (5 AM AST. People all around the country are probably talking about us and all the weather we’re having hereabouts, at least the ones watching The Weather Channel.

Not much ahead to talk about, just a few very pleasant clear days and rising temperatures.

HOWEVER, updating here at 6:11 AM, and having just checked the NOAA spaghetti factory, it does appear, but with moderate confidence, that another dusty cool snap is ahead for 11-12 days from now in a pattern remarkably like the current one with a “Big Trough” along the West Coast again. That event would center around June 7th plus or minus a day or so. It will be fun to keep an eye on this every coupla days.

The End.

Cooking with solar; dusty cool snap still ahead (25th or so)

It was 99 F here in Catalina yesterday.

Spinning entity in AZ today. See it here in the water vapor imagery from the Huskies, the Washington ones. Not much moisture with it, but we did see a couple of….. of…..yes, “Cumulus fractus” yesterday, maybe one big enough to be a humilis, if “big” and “humilis” can be used in the same sentence. In case you missed them:

No ice.

The zoomed shot is because Mr. Cloud-maven person could detect a “pyrocumulus” on top of the Crown King fire on the horizon. Can you?

Here’s the sat image, also from the Huskies, and you can see the tiniest little white spec on the top of the smoke on the left side.

Likely more Cumulus today. Yay.

At least some hot air relief is on the doorstep as a couple of weak troughs buzz the State in the next couple of days, but then its back to The Oven for a couple more.

However, after that, a much bigger cool down is still ahead…

Dusty Coolsnap coming to town

I wish there was a western singer by that name because I would probably buy his/her records.

Anyway, he’s coming to town around the 24-25th-26th, and its going to be real windy, REALLY windy with a lot of dust around, but then we won’t be cooking with solar so much then.

This is due to “big trough” implanting itself in the Southwest then. Will cause a lot of weather mayhem in the West for late May. Here are some scenes from the upcoming “show”, courtesy of IPS Meteostar: Opening the show will be The Ovens, with their hot rendition of 102 degrees (or more) here in Catalina on the 21st.

It will be so great to see “Dusty” after that! Hahahaha. Oh, well, I’m trying really hard here.

OK….now look at all the isobars in the maps below, valid for the afternoon of the 24th and then the 25th! Bunched in the State of AZ those days around that huge low center, first in southern Nevada and then, the next day, over Needles, CA! Wow. It just sits there! This is going to be fun, something besides hot air to think about.

Note, too, all that precip that creeps down into southern Nevada on the 25th. Sadly, that’s about as close as it gets to us here in Catalina. Oh, well, maybe things will “improve” for us as the event gets closer in the models. The real cool down is after the low goes by, after the 25th.

The End.

Yesterday’s awful Cumulus clouds; better ones today!

From the University of WY Cowpokes, this awful sounding from yesterday afternoon at Tucson. Where the two lines first pinch together, around the “500” label, is where the Cumulus cloud bases were yesterday afternoon (marked by the oval)! To see why those Cumulus were awful ones with too much ice, check the temperature lines, the ones that slope upward to the right with the labels on the bottom, “0”, -10, -20, etc. Yep, that’s right, the bottoms of those clouds were at 500 mb, and -20 C! The Weather Cowboy sounding algorithm, the one that produces all the numbers in the column at right, thinks the bottoms of Cumulus clouds were even HIGHER, at 428 mb and nearly at -30 C (that “LCLP” number)!

So, the awful looking, dried out, Cumulus clouds have been explained.

Too high, too cold, too much ice. Reminded me of the old days in Durango, Colorado, in the early 1970s. Charming town, but awful place if you wanted to see Cumulus clouds without much ice. Too high, too cold, and too much ice there, too.

What’s wrong with too much ice?

Too many ice crystals completing for itty bitty amounts of “condensate” (yes, Virginia, even at those temperatures, cloud begin as liquid droplets). But when they are so cold to begin with, so many of the droplets freeze, that they all try to take the water from the ones that haven’t frozen (cause them to evaporate, the water molecules rushing to the nearest ice spec.

So when nearly ALL the droplets freeze, the ice crystals are all itty bitty as well, and can’t fall out, even though individually they may have a bit more mass in them than the droplets. They just float up there and gradually die.

Stories from the field interlude

OK, gotta get this out… In the domain of cloud seeding, where ice-forming nucleants are put into clouds, the phenomenon of having too many ice crystals would be called, “over-seeding”. Believe it or not, deliberately “overseeding” clouds to make them look like the ones we had yesterday, and so that they wouldn’t rain has been tried!

Yikes. Why?

The Coors Brewing Company, in the early 1970s, did not want their hops in the San Luis Valley of southern Colorada (around Alamosa) spoiled by having rain fall on them at the wrong time. The program was ended when alfalfa farmers in the same area, ones that WANTED RAIN, terminated the program prematurely with sticks of dynamite; they blew up the seeding contractor’s radar, used to direct aircraft into the clouds to seed them. Mr. Cloud-maven person, the writer, was working in Durango in those days, on the other side of the mountains from Alamosa, on a scientific cloud seeding project (a randomized one) to see if seeding could cause more snow to fall from winter storms, so he was close to the “action.”

Yes, everyone gets excited about clouds and weather, especially alfalfa farmers! Its so great.

Below a few shots of yesterday’s small, ice-ed out Cumulus.

DSCN1690 — The haze below this little Cumulus fractus cloud is due to ice having formed in it! Bad news from the get go if you're hoping for virga and rain later in the day.

DSCN1713 — Merely a Cumulus humilis, center, and having a bit of puffery. But its mostly ice. Quite awful-looking, really.

About today’s “better” clouds

Overnight there was an invasion of air from the east carrying increased lower level humidity. How cold will the bases be today after yesterday’s -20 C or so? Around 0 C our TUS morning sounding suggests. While that’s still cold, it should mean rain to the ground here and there in the fatter Cumulonimbus clouds that will be around even though they will be dominated by ice again. With these higher base temperatures, it means more water condensing in the clouds BEFORE ice forms. When that happens, you are likely today to get “graupel” forming in areas of the clouds where the condensation is greatest, and the ice just beginning to form. “Graupel” or soft hail, falls rapidly compared to ice crystals and aggregates of ice crystals (i.e., “snowflakes” to get away from jargon) and those graupel up there are likely to be what MAINLY gets to the ground today, melted of course, into raindrops. This because the “free air” freezing level is about 7,000 feet above us here in Catalina (3,000 feet elevation). Should be a fun day, reminding us of out upcoming summer rain season.

And, what do we think about when we think about graupel/soft hail forming in the clouds overhead?

Electricity, lightning! Yes, these clouds will be getting “plugged in”, so to speak, this afternoon here and there. Be watchful.

DSCN1691 — Nice display of Cirrus uncinus in the late morning as Cu began to form.

BTW, if you want a really expert discussion for today, go to Bob’s page here. (He may weigh in on this later…) And, of course, our NWS here. They seem to be getting pretty worked up and excited about today’s weather and all the wind that might blow out of our afternoon thunderstorms.

BTW, nice flowers out there in the desert now days; this on our “Arizona rose” (took about nine attempts to upload this! Bad WP!)

The End.