Still a chance, a small one for a shower today, before it dries out for a few days. Mods pretty sure about rain on the Cats this afternoon, which is good. Should be a very photogenic day, with nice shots of more isolated thunderblasters.
With that out of the way…let us reprise yesterday, the good and the bad.
Only 0.17 inches here in Sutherland Heights yesterday while Saddlebrooke was getting shafted, rain shafted, that is. Moore Road at La Cholla, over there, also got more than TWO inches yesterday afternoon. You can check the interesting amounts here and here.
Another near miss here at the house. May have to sell if this keeps up. July rain here in Sutherland Heights, now at only 2.87 inches (normal is 3.5 inches) while everywhere within radius of two miles has more, for example, about 3.5 inches already over there to the south on Trotter (just S of Golder Ranch Drive), and 4 or so inches in places in and around Saddlebrooke, almost within ear shot.
Here are the effects of more July rain than here; these shots from yesterday morning down in the Regional State Park next to Lago del Oro Road:
8:05 AM. For depth perspective, riding pal, Nora B., co-author with hubby of “Wildflowers of Arizona”, admires the vegetation as she usually does being a big vegetation “author” and all that. This is how the summer vegetation is erupting in Cat Regional Park now where they have had more rain than I have. :(…. Might be worth a look down there. Think about it. Also note; she forgot to put the saddle on my horse, Jake. How funny is that? Also shows I have a friend that doesn’t mind an excessive amount of cloud chatter, unlike our former engineer, Jack R., , who had to rip his headset off when I spoke about clouds to crew members on our research flights at the University of Washington. I liked Jack, though, shown below for reasons of nostalgia.
The late Jack Russell, 1942-1998, engineer with the Cloud and Aerosol Research Group, University of Washington. He kept EVERYTHING running, though he was not fond of cloud talk! I ahd to tell him about cloud instruments that were busted, but we kidded around a lot, too, leading a grad student who observed our relationship to say, “I don’t know whether Jack loves you or hates you.”
Continuing with vegetation shots after nostalgia break:
Also had a surge down the CDO wash. I know you like to see this, you love water, so here are two shots from yesterday afternoon after the Saddlebrooke mash down:
3:17 PM. The CDO wash at Wilds Road.3:12 PM. Just as the surge passed at Wilds Road down by the mail boxes.
While the rain was a disappointment, all the other scenes yesterday caused more than 200 photos to be taken from it. Since I have termed myself, rightly or wrongly, as a “cloud maven”, I should show you ones I thought were exceptional, pretty and or dramatic. The first one, while I was looking forlornly at the Saddlebrooke cloudburst, “Why there, and not on me?”:
1:17 PM. The Saddlebrooke mash down as it was happening. Thought it might propagate this way, that is, the push of wind out of this send up a giant Cumulus to Cumulonimbus over ME, and while the sky darkened for awhile, no real cloudburst occurred.
Here’s what rips your heart out, the big, smooth-looking base indicating a good updraft right overhead but nothing comes out. The giant drops, those ones that are the biggest ones in the cloud could be coming down, defeating the updraft that’s been holding them up there because they’ve gotten too big and heavy for it, and likeyly they were even were big hail stones or giant graupel particles (soft hail), and they’re up there. but the strands of those biggest drops begin to streaming downward just a mile away you see. First, you have some sky rage seeing those strands reach the ground just a mile away, your face reddening, but then, being by nature more contemplative, resign yourself to yet another miss as now the sky fills with dead looking debris cloud upstream of you, only producing light, steady “little baby” rain at best, rain that wouldn’t amount to that much, only might be important to a flying ant colony, but that’s about it. Heartbreak Hotel, right here, overhead yesterday, started thinking about moving on again:
12:51 PM. Harris hawk takes advantage of updraft feeding Cumulus congestus base over the house. My heart was aching for those giant drop to start falling out. Did the hawk know he was safe from that event somehow wherein he might have had trouble flying? Maybe he was sensing that the updraft was too chaotic, broken up into small bits, some genetic implant passed down over the eons? Will be watching for hawks under dark cloud bases and what happens now.1:38 PM. Another Cu congestus base almost directly overhead. Was overhead a coupla minutes earlier. Not as smooth now as it was then, suggesting the updraft is getting chaotic. Darn.
Thought back, too, to all the promise, the propitious start to the day with those thunderheads, mimicking hydrogen bomb blasts, over the Mogollon Rim on the north horizon at 9:30 AM. As a cloud maven junior, you would been thinking, “THIS is going to be a special day today.” Here’s that distant scene, so fabulous to see, from Equestrian Trail Road:
9:34 AM. Giant Cumulonimbus calvus clouds line the Mogollon Rim already! This is a great sign for a “big day” with a good chance the same kind of air that let this happen there is over us, too! Watch out, Catalinas!11:45 AM. Sure enough, there they go, thunder on the Cats! Superb. Note anvil peaking out on the right side, middle. Oh,well, you know the rest of the story. Still, there were so many great cloud scenes all day. I loved it overall.
The first t yesterday, from growing clouds topping Mt; Lemmon was at 9:30 AM, the earliest such event of the summer. Cumulus that grew immediately into Cumulonimbus clouds, then one cell after another in a continuous stream came off Mt Lemmon with no breaks in the dark bases above the spawning area. Had never seen that before. Usually there are breaks between cells, a brief clearing on even the most active days. And those cells really must have sprouted upward around 11:10 AM when, finally, a second blast of thunder occurred. After that grew much more frequent, and by early afternoon, it was almost continuous. Very exciting, as steady rain fell here.
Here in Catalina Sutherland Heights, we were the beneficiaries of the more stratiform (flat, dissipating) part of those Cumulonimbus that stayed rooted on the mountains. Those flat portions provided a more or less gentle rain amounting to 0.18 inches here. However, more than an inch fell in the Mt. Lemmon and Samaniego ALERT gauges. You can see more rain data here from the U of AZ rainlog. org home page. It is a certainty that some mountain sites got considerably more yesterday if you saw the repeated dense shafts of rain S of Samaniego Peak, where 1.10 inches fell. Guessing the peak (but non-measured total) was more like an 1.5 inches. This should recharge many of the normally dry creeks and streams on the Catalinas, and keep the green coming.
Another aspect, making yesterday one of the best visually pleasing days was the absence of haze and smoke. The sunlit Cumulus clouds that were forming away from the mountains and over Oro Valley were especially, pristinely white and gorgeous; took your breath away to see them piling up so high, and so purely, brilliantly white, so clean looking.
Here are some shots from yesterday, beginning with some “morning castellanus”, which were nice to see, too:
7:50 AM. Always a hopeful sign, Altocumulus castellanus float lazily to the north of Catalina.8:27 AM. Altocumulus castellanus growing into sizes that they would now be called, Cumulus clouds. Those very flat bases tell you that they are not from plumes of warm air from the ground, but are associated with a moist layer that’s being gently lifted. Its clouds like these that produce our dawn thunderstorms and showers from time to time, and indicate there’s a disturbance in the area lifting the air. It was another hopeful sign of a significant rain. These clouds, unlike the ones that were starting to grow over our mountains, tend to dissipate lin the morning hours after the sun comes up and burns them off.8:12 AM. In the meantime, actual, ground launched Cumulus, from the slight amount of morning heating, were already starting to puff up from Ms. Mt. Lemmon. This was really unusual. You can tell that these are “real” Cumulus because such ground plumes of warmer air produce more irregular bases and scattered shred clouds, show more turbulence (movement) when you watch them than Ac cas clouds, the latter seeming to be almost motionless. Bases of these starting Cumulus not too much different in height than the castellanus clouds in the prior shot. Looks like today will be a big day for captions, if nothing else!
9:25 AM. The first Cumulonimbus is about to announce its presence with a thunderblast. No precip evident here, but aloft, next shot, is the “ice” in the overhanging anvil.9:25 AM, overhead view showing that this buildup had already deepened upward enough to form ice, and was about to let go of some precip. See arrows.9:31 AM. Seconds after first, and completely unexpected thunderblast. Didn’t look big enough. Top of Mt. Lemmon is obscured in heavy rain.
11:13 AM. Finally a second blast of thunder occurred in this cell, though one rain shaft after another drifted across the Catalinas, fading away as they continued across Catalina and Oro Valley.11:14 AM. A look at the downwind part of these storms where only the deep, flat portion remains. Yesterday we were lucky since it is often too dry underneath these portions for the rain aloft to reach the ground. Steady light rain was occurring at the time of this photo, while deluges were taking place on Samaniego Ridge. Rain from these Cumulonimbus portions shown here is mainly due to melting snowflakes while the strong shafts are produced by melting hail and or graupel,that began as as frozen drops or ice particles that subsequently get heavily rimed (coated with ice) as they collide with supercooled drops in the vigorous rising portions of Cumulonimbus clouds, finding their way down as the updraft weakens or collapses entirely. I can;t believe how big these captions are getting, but it can’t be helped.11:27 AM. While things were “humming” along from the Catalinas, Cumulus arose elsewhere in a hurry, producing this gorgeous scene. This cloud is a Cumulonimbus calvus, that short-lived stage when a congestus begins to form ice in its top, but has not gotten to an obvious fibrous stage. That ice is present is seen in the rainshaft already pouring out of this cloud. Can you see that the very top is ice?
6:52 PM. As with many active days, yesterday ended with “debris” clouds from the many Cumulonimbus clouds that formed early in the day, providing a comfortable, overcast evening. The clouds are Altocumulus, at two different levels, with an Altostratus overcast above. Who says Arizona is unbearable in July? Some of the most pleasant days of the year are now.
Today is supposed to be another early starter as well with rain on The Lemmon before noon, the model runs at the U of AZ from last night say. However, the longer term model runs indicate a break in the summer rain season for a few days after today. I guess that’s when our weather can be that bit unbearable here in July. Phooey.
Cloud bases were very warm again yesterday, 15-20 C (59-68 F) paving the way for thunderstorm rainfalls similar to those seen in the Southeast US, inches in an hour or so. Didn’t happen locally, but just to the north of us toward Park Links Road and up toward the Florence area, likely happened as one giant cell after another formed between Saddlebrooke and Florence.
Those were the only clouds that produced thunder yesterday. Less vigorous clouds rained, but didn’t have the ingredients to be thunderstorms, stronger updrafts, apparently. Also, at times it appeared some of the rain, to this eyeball, was “warm” rain, rain formed without ice, a rarity here in Arizona (something that happens all the time in Hawaii, and over the oceans.)
And if you were sharp, you saw something happen yesterday that is also quite rare; the clouds erupt in our vicinity into Cumulonimbus by 9 AM from surface heating (they weren’t those nighttime showers that tend to fade as the sun comes up). That was exciting because when they took off, it seemed like a day destined to have giants here.
But then something happened, drier air began to move in from the east, and pretty soon, the ONLY large clouds were to the west and north, a sure sign a disturbance aloft was moving through and less favorable conditions for rain would follow it, the normal “couplet”, or sequence.
Sure enough, the clouds over the Catalinas, after such an auspicious start, struggled to grow into Cumulonimbus clouds, as they did elsewhere to our southern flank, while we watched one magnificent Cumulonimbus after another rise up to the north.
Fortunately, a moistening and destabilizing regime of air is moving this way from Texas across northern Mexico toward Douglas, and so our day here in Catalina should be more enlightened, by lightning.
Yesterday’s clouds
6:15 PM Cumulus congestus forms over Oro Valley in smoky air. Died away in 20 min. Nice, isolated example of that cloud, anyway.1:42 PM. Another one of the large Cumulonimbus capillatus clouds forms just north of Saddlebrooke.1:36 PM. Looked like a promising sign that the clouds on the Catalinas might still erupt into Cumulonimbus after the brief shower an hour earlier. But no. Looking like someone exulting over a three-pointer, hands raised, it turned out to be a case of cloud erectile dysfunction. It flopped back down in minutes. HELL, we can talk about things like that because we hear about them all the time during our favorite TEEVEE shows! BTW, “TV party tonight!”12:27 PM. The very most hopeful part of yesterday. Forming over Charoleau Gap was this beauty. I thought I was going to see the first strands of large drops/and graupel pour out of it at any moment. I was so happy then. But then, only misty-looking rain fell out, no strands, filaments, suggesting maybe that it was rain due to drops colliding together rather than from ice/hail mechanism. Well, did get measurable rain, but only 0.07 inches.10:55 AM. What a behemoth this was, dumping its inches, producing the first thunder of the day, north of Saddlebrooke.9:13 AM. First Cumulonimbus forms out of the growing field of Cumulus clouds. Can you see the ice shield peaking out on the left?8:26 AM. To see real (ground launched) Cumulus sprouting like this so early in the morning was incredible; hopeful signs of “big day.”
At least it wasn’t predicted the day before, but how nice to see a “mesoscale convective complex1” (a bunch Cumulonimbus clouds clustered together) come roaring over the Cat Mountains yesterday morning. Here it is, in case you missed it and want to see it again, from the beginning when what was going to happen was in doubt:
11:00 AM. Major rainshaft, and accompanying dark base where updraft is forming new precip approaches Catalina area.11:47 AM. The dramatic backside of this cluster, resembling those seen in the Plains States; good mammatus, too.
It was great, too, to see some evidence of water on the ground, and several natural livestock ponds form due to the storm. Its been too long since puddles formed. I like puddles, BTW2.
11:18. Evidence of significant rain; a puddle has formed.4:38 PM. Calves inspect newly formed livestock pond on Equestrian Trail Road. Mom not impressed.
Go here to see some regional rainfall totals from the Pima County network and here for the U of AZ network.
What was best was the clarity of the air after the rains washed all that smog, and we had our brilliantly white clouds against that deep blue sky back:
4:10 PM Cumulus mediocris over the Catalinas.
Today:
First, right now (6 AM) we have some of the best Altocumulus castellanus around I have ever seen. So pretty!
U of AZ 11 PM mod run expecting afternoon showers/TSTMS over Cat Mountains today, trailing off to the NW and near Catalina proper. Showers and lightning now to the S-SW, expected to die out before reaching us. So, happens, look for bases launched in the late morning and early afternoon to drift overhead–often a street of clouds forms over the southern portions of the Cat mountains about where that dark base in the first photo is, and if we’re lucky, will dump in this area. Look toward Table Mountain and a stream of clouds from around there headed this way.
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1It would be great if you used this term with your neighbors when talking about yesterday’s rain: “That was a great MCS that came through yesterday morning! Hope we get another one today, though rain in the morning here is rare, but anyway…..” Neighbor “A what went through?” You: “Oh, sorry, I meant a nice cluster of thunderstorms. ” You continue: “As a cloud-maven junior, I’m learning a lot incomprehensible jargon that I can use to impress neighbors. Hey, have you heard of the ‘diffusion domain’? That’s when you’re flying in clouds and you can’t see either the ground or the sun! The next time you fly and that happens, tell the passenger next to you…..”Hey, I think we’re in the diffusion domain.”
2Photographed a lot of puddles on a trip to Death Valley in 2005 (wettest rain season there in 75 years). It was a lot of fun for me.
Yesterday was a disappointment. Oodles of water up there above us, as represented by cloud bases somewhere around 15 Celsius (59 F) yesterday morning, early Cumulonimbus activity–one was up toward Oracle by 10:37 AM–Oracle got 1.06 inches yesterday, but while the skies darkened over Catalina several times, they didn’t “unload.” Maybe only once or twice before in six summers have I seen this darkening to the level we had yesterday, without a rain shaft soon falling out of it. A couple of examples from yesterday:
1:29 PM. A Cumulus congestus takes shape over Cat State Park, and heads toward Catalina. Only sprinkles fell.2:40 PM, looking toward Charoleau Gap. It doesn’t get more “portenful” than this. I was SURE a shaft would crash down, and with it, the WIND from the north, the clouds then building over ME to the south, as happens so often when heavy rains pour down on the Gap. Didn’t happen, at least not until too late, long after it had moved farther north. Got pretty dejected.
So, what went wrong? Why were the clouds SO DARK, even shallow ones like Stratocumulus, let alone the Cumulus congestus, but with so little “emitting power”?
The darkness of these clouds was surely due to the high smoky aerosol content of the air that led to unusually high droplet concentrations in these clouds. The higher the droplet concentrations, the darker the bottom of the cloud, say holding cloud depth constant. So, a moderately deep cloud, but one too shallow to rain, can look like these, like the normal darkness on the bottom from which blinding shafts of rain fall. So, most likely we were looking at smog-laden clouds, the kinds of ones in our future around the world because that’s what we do, produce smog and smoke, well, us and lightning.
And, as we recall from Squires and Twomey (1967), smoke inhibits the formation of rain in clouds. I am sure most of you remember that article about smoke and sugar cane fires in Australia, and how those smoked up clouds did not rain like the ones around them that were “clean.” This phenomenon has been reported on numerous occasions since, like how in LA it helps reduce drizzle (mist rain) occurrences.
However, as we know, even smoked up clouds can rain IF they get high enough to reach the -10 C level here because then copious amounts of ice, soft hail and snow will form aloft, and down it will come! That only happened in isolated places, like over Oracle where they got that inch of rain (at least around here). So another cause of dark clouds lacking in downspouts was that they were not QUITE deep enough for the tops to reach -10 C. up around 20,000 feet above the ground yesterday–those tops were SURELY so close, though!
Back to smoke effects. With bases as warm as 10-15 C yesterday, there should have been rain formed without ice, and almost certainly a little did (these eyeballs detected some yesterday afternoon on the Catalinas). However, this is the type of rain that smoke inhibits most. This is because with so many cloud droplets competing for a given amount of condensation, they all stay too small to collide and stick together (requires drops bigger than 30 micrometers in diameter (let us not forget Hocking and Jonas (1970)…. So, we lost some rain due to smoky skies there, too,
Next, it can be relatively cool with tremendous amounts of rain IF there is a good disturbance to cluster the clouds together, forcing converging air near the ground, taking it away at Cirrus levels. We didn’t have a “disturbance”, a trough or a low to help out.
Finally, without the help aloft, we needed, as you can all guess by now, that bit more heating at the ground, maybe just a few degrees was all to launch some really large but isolated storms.
Today?
U of AZ 11 PM mod run has Cbs developing over the Catalinas by noon, and during the afternoon some of those showers trail to the northwest over Catalina. I think one will. So, once again we have a day with rain around, and maybe today a little cell will bombard us with a quarter of an inch. Should be warmer, today and that will help since again we have no trough help. Still smoky, as you can see here at sunrise by that orange-brown layer below this morning’s Cirrus. So, once again, the clouds may look a bit darker than they “should” when we have clean air.
The End except for this nice morning shot of Ac perlucidus undulatus I would call it. Very nice!
6:54 AM. Altocumulus perlucidus undulatus, if you care.
BTW, finally got a “submission” in late yesterday about our neat storm after what was deemed a power outage of some type affecting the hosting service yesterday. After re-reading it, perhaps I had too much time to think about it… Oh, well, onward.
First, from yesterday, a day with occasional sprinkles, dessert:
6:48 PM. Residual Stratocumulus and Altostratus translucidus from a cloudy, unusually cool April day.
The remarkable thing about yesterday, and you might have thought it was fog, was the amount of dust in the air after the rain and after the winds calmed down from those 50-60 mph blasts from yesterday. Well, it was plenty windy in the deserts behind the rainy frontal band and that dust-laden air moved in right after the front went by. At first glance, and since it had rained, I thought it might be fog! But a quick check of my senses and the relative humidity, which needs to be near 100%, showed that it was only around 60%, the measurement that demonstrated it could not POSSIBLY be fog. There you have it. Problem solving for you by C-M.
Here’s an example of that dust:
7:12 AM. The unusual sight of thick dust below Stratocumulus clouds and only hours after a substantial rain.
With cloud tops yesterday only having to reach to 11,000 feet above sea level to surpass the magical -10 C (14 F) temperature level, hardly much above Ms. Lemmon, ice and virga from these clouds was virtually guaranteed. And, if you were watching, there was plenty, including from those clouds we couldn’t really see so well due to dust, ones that produced those several morning and early afternoon sprinkles (“its not drizzle”, a continuing theme here. Only a meteorological ignoramus would call a fall of isolated drops, “drizzle” (or snow and rain mixed together “sleet”). Perhaps I am too strong here, but it is important to get it right since REAL drizzle and sleet (raindrops that freeze on their way down through a shallow cold layer) tell you important things about the clouds and layering of the air overhead. Here are some of yesterday’s clouds as the dust thinned (both due to mixing upward into a greater depth, and due to clearer air moving in):
9:09 AM. The dust remains, but the Stratocu is mostly gone. Twin Peaks still not visible from Catalina.10:13 AM. Dust lifts as Cumulus arise on the Catalina Mountains. Nice view of “Catalina Heights” manufactured home country, too, where C-M lives.12:20 PM. By mid-day, quite a few of the highest tops of the Cumulus-Stratocumulus complexes had likely surpassed the -10 C level, probably much lower, to -15 C or lower temperatures, and scattered virga and snowshowers were aplenty in the afternoon.3:20 PM. By this time cloud tops had descended, weren’t so cold, and those Cumulus and Stratocumulus clouds just kind of sat around not doing much but making pretty shadows on the Catalinas.
By mid-afternoon, most of the deeper clouds with substantial virga were gone. You can see what happened in the mid-afternoon here in the U of AZ time lapse movie (as well as the thinning of the dust haze we had yesterday) here.
The weather ahead
No rain has popped now in the mods for some time regarding the passage of a trough on the 17th, just some wind with it, though not anywhere like what we just had. In the drought relief department, it was another great day yesterday for portions of KS and NE as shown in the WSI Intellicast radar-derived precip map:
The 24 h precip totals for the US ending at 5 AM AST this morning.
Of course, the title refers to Dickens’ little known sequel (and frankly, a lightly regarded one) to his popular, “Great Expectations”. Dickens fully expected that by rushing out another novel similar to “Expectations” that a financial success similar to the one that “Expectations” had garnered for him would be easily acheived.
However, like most sequels, his effort was weak and appeared to be thrown together to merely take advantage of a gullible public. However, and much later, his sequel came to be regarded as a semi-clever, though lightly disguised, slam on the early English weather forecasting system, which was, of course in those days, was map-less, model-less, and mainly consisted of limericks and folk sayings:
“Birds flying low; beware the Low1.”
Forecasts were quite bad in those days in which Dickens lived, naturally, ships went down regularly due to unforecast storms, and Dickens wanted to dramatize this to his readers in his sequel; the various twists and turns in the plot of that sequel now thought represent ever changing, unreliable forecasts. He had hoped, with his satirical sequel, to provoke advances in weather forecasting, which he did. Isaac Newton, joined by Leibnitz, took wind of the Dickens sequel, and together they invented calculus, a tool which which allowed the calculation of the movement of air using the laws of fluid dynamics.
—-End of historical antedote2——————————
A surprising overnight rain
Well, even C-M and associated models like the Beowulf Cluster as of the 5 AM AST run on the 8th, did NOT see 0.38 inches from “Joe Cold Front”, who was supposed to pass by as a dry front, not a wet one. Still, it was fantastic surprise, one that could have only been made better by having forecasted it from this keyboard; going against the models big time. And THEN to hear Joe’s rains pounding on the roof as he went by between 10 PM and midnight. Oh, my, euphoria. BTW, the temperature dropped from 60 F to 43 F, too. Whatafront! Thank YOU, Joe.
You can see some rainfall totals from the Pima County ALERT gages (April 8th-9th rainfall). We “northenders” pretty much got the bulk of it, with Pig Spring, 1.1 miles northeast of Charoleau Gap leading the way with great 0.71 inches. Ms. Lemmon was not reporting at this time because it fell as snow. So look for a frosty Lemmon this morning. BTW, Sutherland Heights picked up 0.42 inches, and had “pre-rain” gusts to 58 mph! Whatastorm!
Continuing now at 7:21 AM after a “godaddy.com”/Wordpress meltdown an hour ago.
BTW, all the haze out there is dust under the clouds, not fog. Its pretty unusual to see something like this, especially after a good rain, so you’ll want to document it with photos and a little paragraph or two about it, and how it makes you feel. There was so much dust raised behind Joe throughout AZ and Cal that its rainband could only do away with that dust within it. This overcast situation should gradually breakup as the day goes on into more cumuliform clouds, ones with large breaks between them, the dust probably hanging on most of the day. With the -10 C level, the usual ice-forming level here at just around 11,000 feet above sea level. So it should be easy for the taller Cu to reach that and spit out some isolated precip later in the day.
Signs that the forecasts were going bad in a major way was when lines of clouds and some with precip formed in southwest Arizona late yesterday afternoon. Here’s a nice map of that development, one in which caused the tiny brain of C-M to think that it might rain, probably you, too, and anyone else that looked.
5:30 PM AST visible satellite image from the U of WA.5 PM AST 500 millibar map. You can just see that little line of clouds, and you can also see how the jet, wrapping around San Diego and headed this way, partitions the clouds. I think this is called a “teachable moment.”
Some scenes from yesterday’s dust, from the beginning. Save these for posterity:
8:21 AM. No sign of dust.1:47 PM. Dust haze becoming increasingly noticeable.2:00 PM sharp. Mr. Cloud Maven person’s cap blows off about 40 yards down the road in spite of having warned others about having this happen.2:04 PM. Dust increasing rapidly, wind peaking at 55-60 mph in the Sutherland Heights district. Twin Peaks no longer visible.3:02 PM. Small Cumulus (humilis and fractus) increase in coverage as dust limits visibility to around 10 miles.6:38 PM. The yellow sunset, indicative of large aerosol particles associated with dust.
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Feeling good about rain here, feeling good about rain there
Not only can we exult over a surprise rain of some substance, but look what has been happening in the droughty central Plains States. Below, from WSI Intellicast’s 24 h radar-derived rainfall amounts for the US (april 8th, then April 9th at 5 AM AST. Especially take stock of the amounts over the past two days in those worst drought areas of Kansas and Nebraska. So great! And this is only the beginning of a huge rain/snow event in those drought areas!
24 h rainfall ending at 5 AM AST April 8th.
The End
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1Hygroscopic insects adsorb water molecules and are weighed down in conditions of excess humidity, the kind that often precedes a storm. Birds then fly lower, too, to grab lower flying insects, or so the saying goes. (I am quite pleased by the kind of information I provide for you almost everyday.)
This from Canada last night for April 8th at 5 PM AST: appropriate descriptor for AZ; “juicy.” This was such a great find early this morning!
Note deep upper low at 500 mb in eastern Cal (upper left panel) and gigantic surface low centered in Four Corners area (upper right panel). Would almost surely mean rain here in Catalina 24 h after these panels (the last one in the forecast series). If these maps verify this would be another billion-trillion dollar value storm in drought relief for the Southwest AND Plains States over the days following this map.
However, you will be as moribund as I was after looking at the USA WRF-GFS model output for the SAME moment in time, 5 PM AST April 8th below. I had hoped both models would show the same thing, which would build confidence on what’s going to happen on the 8th-9th, but they are vastly different! Take a look at THIS upper level pattern: no low in eastern Cal, just a strong jet pouring down from the Pac NW with cool air. No moisture of consequence here in Catlandia with a pattern like the one below.
Also valid at 5 PM AST April 8th, for the 500 millibar pressure level.
So who you gonna call when these kinds of things happen? Spaghetti!
Well, if you know anything at all about “spaghetti” you will only get more moribund, maybe start crying when you see it for the same time as these models. The Enviro Can mod is clearly an outlier “solution” even if though are dealing with different models. Inserting some “chaos” in form of “bad balloons” (bad data) at the start of the USA model run does not reveal a pattern with a low in eastern Cal in any of the “ensemble” model runs, but only results in a strong signal (line bunching) for a jet to whoosh down the interior of the West Coast that then loops back toward the northeast over and east of us–not good for precip here, just a rush of cool-cold air.
However, it WILL still be a pattern that’s great for Texas and the Plains States in general, so let us not be selfish in our dryness and begrudge others who get rain, but rejoice with those droughty others who will get so much relief beginning around the 8th as shown here–and that relief lasts for about three days, too. Just hope there aren’t too many tornadoes in Texas and eastward…
As an aside, it might be worth the drive to central Texas to see some of those Big Boys out there, get some perspective on Nature’s power.
Valid for 5 PM AST, April 8th.
Yesterday’s clouds, those small Cumulus, almost beyond the curvature of the earth to the north-northwest
Only the truly great cloud maven juniors of our time would have observed and logged in their weather diaries those tiny Cumulus clouds (humilis and fractus) that appeared momentarily off to the north-northwest horizon, barely visible, from Catalinaland around 5:12 PM. Since I had foretold some distant Cumulus to the north yesterday, I damn well was looking the whole afternoon, straining eyeballs, and was starting to feel sad until I saw this one cloud, and then I was SO happy, euphoric really. I think this one, and a couple of others needing a microscope to see, were there for about 15 minutes is all. Here is that photo-documentation of a small, distant Cumulus humilis. I’ve added some writing on this photo to help you find it, but you will have to blow it up.
Also, its OK to log things you missed in retrospect into your weather diary; it helps make it more complete. BTW, there were also a few little patches of Cirrus.
May take Jake Horse out to see if the Sutherland Wash is running, anyway, if the CDO is not running here in Catalina.
Thunderstorms (at least 4 separate ones yesterday), with hail, graupel, wind, rain; what a nice day for Catalinans and our environs. Lightning was still visible as of 7:52 PM last evening, and close enough that thunder could be heard, technically meaning a thunderstorm is in progress in weather parlance. Here’s some pea-sized hail for you, sent by a listener, “Dave”, in Sutherland Heights:
Was awakened by a moderate rainshower just before 3 AM. Dropped 0.03 inches in a few minutes, to bring the total to 0.40. Another shower followed within half an hour, but bucket didn’t tip for even 0.01 inch. May have to jiggle it to get that extra 0.01 inch that I KNOW fell. Hahahah.
In the meantime, exulting over the large amounts, so well foretold by the U of AZ Beowulf Cluster run from 24 h ago. Truly amazing! Our total here was also well=predicted by that model; amounts in this storm increase northward reaching 0.87 inches at Oracle State Park, 0.55 inches at the NE corner of Saddlebrooke. We SO needed a good rain. Here’s where the totals are:
Here are some mind-boggling statewide totals from the USGS, some approaching two and a half inches of water content at Sunflower near Payson! How great is that?! Really, this has been a billion dollar storm in dropped water and snow. Maybe it should have a name now.
You will can also access rainfall data from the U of AZ rainlog.org network here, and from CoCoRahs national network for Arizona here. As always, its necessary to point out that in the rainlog network, the measurements reported this morning will be assigned to yesterday’s date, while the ones in the CoCoRahs system will be assigned to today, March 9th.
Since its unlikely to rain for at least 10 days, I thought I would overdo the precipitation data for our billion dollar storm.
Sadly, as you will see in this Pima County ALERT gauge totals above, we in the north end of the County really got the nice rain; most of the county did not. We were lucky we were that bit farther north because it wasn’t the wind direction helping us out in most of the storm; that “help” is taking place now because the wind is more from the west at cloud levels. Going into yesterday yesterday evening the wind at cloud/mountain top levels was from the south-southwest rather than from the west, and normally that more southerly flow helps the south facing sides of the Catalinas, as much as us. So, it was more to do with cloud top temperatures and those clouds being a bit too warm to the south, while northward and to the northwest (perpendicular to our jet stream), the temperatures decreased rapidly at the same level in the atmosphere, and that in turn, allowed cloud tops to deepen more as they went nortward. Make any sense? Here’s a map of temperatures aloft for yesterday, two graphics to try to explain this:
A 500 millibar map at 5 PM AST. Center of coldest air is to the northwest of us at that time, gets colder over you as you take Highway 79 to Florence and beyond. Cloud tops do, too. The full loop is here.
Mapm for the same time with colors showing temperatures getting colder to the NW of us. More likely to have deeper clouds and thunderstorms as you go NW. Full loop is here.
First, here’s last evening’s TUS sounding, as rendered by the Cowboys of Wyoming. Its got some writing on it:
The Tucson sounding at 5 PM AST, yesterday, March 8th. Cloud tops marked by asterisks to represent ice crystals, and bottom by little “o’s”. The arrows in roughly an “R” shape is an attempt at replicating the thunderstorm sign used by NOAA. Even though the clouds were topping out at less than 25,000 feet, they still contained enough ingredients such as hail and updrafts to generate enough static electricity for lightning.
———begin tedious stream of consciousness again, probably worth skipping——–
Graupeling hard here at 3:38 AM! Third shower since getting up! Pounding roof. Very small, like rice grains. Just quit, like someone turned a light off at 3:41 AM. Tells me its a new cell that just formed with narrow strands of precip/graupel. Investigating…no echo at 3:36 AM nearby… waiting for next 6 min sweep… 2:42 AM: No echo! I have not seen this happen before. Could it have developed and died in less than 5 min? Did not tip bucket! Its just like yesterday, we had no less than four hail/graupel episodes and I was beside myself thinking of those balls of ice bouncing OUT of my rain gauge collector! I was being short-changed in the amount of precip I could report. I think I am going to have to add to my rain total, maybe 0.03 inches due hail balls that bounced out
——————–end of tedious stream———————-
OK, now up to 0.13 inches in rain that has fallen since about 3 AM. This is great, because now the total amount in the storm is 0.50 inches here!
Yesterday’s clouds
After a few sprinkles-its-not-drizzle amid brief sunbreaks yesterday morning, the first thunderstorm rumbled across Marana and the Oro Valley at 9:30 AM.
9:55 AM. Thunderstorm with hail and heavy rain moves into Oro Valley.10:21 AM. Looking upwind toward Pusch Ridge at the bases of a line of rapidly moving Cumulus congestus clouds.10:25 AM. Hail-producing cloud has passed by, but shaft increases in size and visibility. This is a time when tremendous amounts of ice is forming in the cloud, ultimately leading to its demise as a fluffy area looking area of only ice crystals. Without the liquid droplets, that disappear during this stage where ice forms explosively, no graupel or hail can form. Its a normal life cycle event for cells like this.12:12 PM. Another line of young Cumulonimbus clouds races toward Catalina and Sutherland Heights, a recurring theme yesterday.12:23 PM. Passage of that complex of Cumulonimbus clouds shown in the prior shot resulted in this hail shaft trail on the foothills of Samaniego Ridge. Hail shafts are very narrow. If it had been snow, there would have been much greater coverage.2:30 PM. But the day wasn’t done then, was it? Here something in the way of an arcus cloud rolled across Oro Valley and onto the Catalinas. Thought maybe a tube might form.4:55 PM. Just kept on giving. Here yet another line of developing Cumulus congestus, just reaching the precip stage a little upwind of Catalina, dropped a few more graupel particles while going on to dump heavily farther north. This recurring pattern of clouds developing, able to become deeper with colder cloud tops is the primary reason the north part of Pima County did so well yesterday and this morning,
Today’s clouds
These early morning stratiform (flat) clouds will disperse into Cumulus and Stratocumulus in clumps. They’ll be cold enough at cloud tops for ice and virga, but clouds likely will be too shallow for more than a hundredth or two in the heaviest precip areas around Catalina. Things dry out later in the day, the Cu becoming smaller, so the best chance of measurable rain is before, say, 2 PM.
Get camera out fast, too. THere was a huge dump of hail or snow on Charoleau Gap last night or this morning I suspect, and it looks spectacular even now at 6:53 AM. Its local, because its not seen at the same elevations to the south on Samaniego Ridge. But, it will just be gorgeous with those deep blue skies and white Cumulus clouds all around.
This is so great, today’s badly needed substantial rain for our Cal pops and other wildflowers, now beginning to bloom. You may have seen some poppies along North Oracle Road in the past week.
Here is the current radar and cloud situation from IPS MeteoStar (loop is here). You can see three rain bands, very similar in configuration to the historic snowstorm of February 20th that also had three bands. What’s potent and interesting is that the lead band with precip just to the west of us (passing over Ajo at this time). That cloud band is usually just that, composed of thick, middle and high clouds (Alstostratus/Cirrus/Altocumulus) without any precip or just virga. And its usually also followed by the “clearing before the storm”, the ones that lead on many occasions to those super spectacular sunsets before the surge of low clouds and precip. You can see that “clearing before the storm” aspect in southwest AZ in the image below.
But, as you can see, THIS cloud band “before the storm”, has developed some rain. So, in this case, we have a chance to pick up some light rain before the major bands arrive later in the day. You can also follow the progress of the storm on those great WunderMaps here. Might be on this site ALL DAY.
4:10 AM combination satellite and radar, the best on the web IMO.
Here, too, is the University of Washington’s 500 mb map for 5 AM AST this morning showing the flow at about 18,000 feet above sea level. You can see the three bands here, too, and a fourth taking shape in the center of the low, now off southern California. You will see that the strongest winds at this level are over Tucson now, meaning rain is imminent, and it is. Already had a trace, a few drops fell at 4:06 AM. Expect lightning in AZ today, maybe around here, too, with the second or third bands.
Here’s the loop U of AZ weather department’s mod output from last night’s 11 PM run, which gives you an hour by hour account of the storm over the next two days. While the main bang is today, a lobe of cold air aloft follows it and scattered light showers continue into tomorrow. What will help Catalina’s rainfall is that the wind will be more westerly rather than southerly at cloud levels during and after the storm, which means they will pile up on this side of the Catalina Mountains the best, and which should do better than other areas. The U of AZ mod knows something of this, and you can see the precip in the panel below extending from the Catalinas toward the west and over us. Its due to this frequent occurrence during and following storms that really boosts our winter precip totals over surrounding areas of similar elevation.
There are a lot of parameters available from this output. You can look at the whole range of them here.
Valid for 3 AM AST tomorrow morning, March 9th.
Yesterday’s clouds
It was asserted yesterday that there would be some Cumulus and Cirrus by Mr. Cloud Maven person.
Here they are:
4:16 PM. Forecast of Cumulus cloud(s) verifies! It was small, but great.6:10 PM. Cirrus creep underway from the west.
Sure, it was clear practically the whole day, and some people might complain that they got eye strain looking for Cirrus and Cumulus clouds during the day…. But then, you can find people who will complain about anything.
