2:53 PM. Cumulonimbus tops with their anvils line horizon northwest to north. The ones that begin this series on the left are in the Prescott area. See radar chart below. Cumulus fractus clouds are in the foreground.2:45 PM AST. Arizona radar echoes yesterday at the time of the photo. Note little green patch SW of Prescott, maybe Peoples Valley area. Radar courtesy of WSI Intellicast. That would be the leftmost tops. 6:41 PM. Nice sunset with “surprise” rogue Cumulonimbus located NW of Sells. Nice little virga patch hanging down from some Altocumulus next to it. Did not expect a Cb in that direction at the end of the day. Bodes well for today; having Cbs that are a little closer to us.6:46 PM. The sky was completely clear, however, moon intact, S-SW. Note stratified smog layer at the bottom.
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Our desert greening seems to be reaching its peak now, and so it would be nice for you to get out and see it before football day on Saturday and it could start to wilt that bit under our drier conditions. Just after sunrise, and just before sunset, there is some great lighting on our weedy summer desert vegetation.
Canadians1 think the tropical air will hang around SE Arizona for a few more days, with the chances of rain actually increasing that bit on Saturday. The US WRF-GFS model is not quite so generous with precip here, so we will ignore that one. But, in any event, we should have pretty Cumulus, and distant Cumulonimbus clouds for a few more days before The End, after which we have to wait for a hurricane/tropical storm to roar up the coast of Baja and across Yuma to get any real rain.
In the meantime, I am wondering whether you have taken that trip I suggested to SE Arizona to see the vegetation explosion resulting from this summer’s extraordinary rains they’ve gotten down there? Douglas, for example, has just crossed over the 16 inches mark for this summer a couple of days ago, the wettest summer of the past 100 years down that way. The summer desert vegetation down there must be extraordinary, too, and it would really be worth seeing. I will get down there for sure!
It has continued to rain extraordinary amounts of rain in western Arizona. Here is a depiction of just the past seven days ending yesterday morning (today’s image is not out yet). Its a great sight, considering our “extreme” and “exceptional” drought designations over that way.
Seven day radar-derived precipitation totals for the US ending yesterday at 5 AM AST. Just look at how Arizona overall has fared during this period. Amazing. Should make a good dent in our drought conditions. And the generous rains in droughty NM are foretold to continue, good news indeed. (BTW, the excessive precip around Salt Lake City is bogus, due to an error.) There are holes in mountainous areas due to blocked radar beams, so this map under represents the rain that actually occurred. Need more radars!
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1The writer exhibits bias here due to his precipophilic personality combined with having most of his relatives living in Canada. Also, the cruder Canadian model with its larger grid sizes tends to smooth out precip over larger areas than the US WRF-GFS model shown here.
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 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, 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 with a lot of lightning. Still, a gorgeous sight. Looking northwest, beyond Saddlebrooke.
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 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 (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.
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!
6:21 AM. Kind of a Ac lenticularis overhead, due to east to southeast winds over the Cat Mountains. What would those winds mean? Forming side of cloud is at the bottom of the photo, bright white area, or toward the east.. After all, that puts us in the downwind/downslope side of the moiuntains. Could showers still develop over the Catalinas and drift toward us without falling apart as they often due? Yes.12:54 PM. After a grueling drive deep into Tucson, I came home to Catland to find pounding rain, both along Oracle Road at Rancho, and here on ET (Equestrian Trail). Drops, though falling from about 10, 000 feet above us were pretty huge, as you can see. Note, another photo in the collection, “Not taken while driving”, Price, $1,200. The tilt lends an aire of excitement, perhaps danger.
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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!
2:03 PM. Drops away!
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.
“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.
In case you missed it, this eye-candy from last evening as a crepuscular ray highlight some lower Altocumulus below the main layer:
6:40 PM. Lower patch of Altocumulus is under lit by a ray of sunlight. Higher layer would be termed Altocumulus opacus. This was quite a dramatic scene and had to sprint up a hill from a neighbor’s place to get this and the next shot.6:42 PM. Was gasping after sprinting up hill in an obsessive-compulsive pulse to get this shot. But it was worth it.
11:19 AM. Small Cumulus were erupting nicely over Mt. Lemmon and the Catalinas, but oddly, due to the southeasterly winds aloft, they were larger in an extended cloud “street” downwind. See next shot taken at the same time.11:19 AM. That cloud street went for miles!
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. 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 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 (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.3:27 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.
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.
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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?3:43 PM. Zoomed view of the same smogged up scene. See ’em now, just above and to the right of Twin Peaks?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?
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.
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, 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!” 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. 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). 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 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 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 being in the photo.6:46 PM. Expanded shot of same scene, so fabulous, one of the best!
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:
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:
6:36 PM. First, before the pileus shots, the overall scene to the southwest and west, and also why telephone poles and overground wiring, relics of the past, are offensive and need to be removed; those wires put under ground. Don’t blow down that way, either. I’d like to start digging right now! Hope I’m not upsetting you too much with this scene. As a CM Jr., , overground wires are the bane of civilization.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 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:
2:42 PM. Just a pretty picture looking NW across Saddlebrooke with Cumulus humilis and Cu fractus in the foreground and scattered Cumulonimbus and Cumulus congestus on the horizon.11:45 AM. A good sign of an interesting day ahead, that Cumulus sprout over Ms. Lemmon that indicates there is a lot instability (the decline in temperature with increasing height is pretty large) and that further heating will likely lead to deep clouds.4:26 PM. A sight very reminiscent of the previous day, a narrow Cumulonimbus shoots up off the Catalinas. This was the second one in a row like this. Kind of blew up into something considerably larger than the one around 3 PM, with this one’s vast anvil eventually overspreading Catalina and Oro Valley. Here, playfully, it appears to be in the shape of an alien with two arms reaching out, a fibrous, icy one on the left, and a fragmented, droplet cloud one on the right, with a big head between them.
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!
Forgot the nice sunrise and another faint rainbow, two mornings in a row! In case you missed them, again, here they are:
6:01 AM.5:54 AM. Ac opacus.
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, 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 (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.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.
First, yesterday’s sunrise rainbow, in case you missed it.
5:56 AM. Virga/RW– (very light rain shower) from Altocumulus opacus (‘thick”) leads to an early morning treat. The rainbow faintly extends all the way up to cloud base, indicating that the freezing level was at or above cloud base. The TUS morning sounding indicated that this layer was based at 14,000 feet and about 0 C. Some sprinkles did reach the ground, but shadows from terrain or other clouds prevented the bow from reaching the ground.
“Dumps of the Day”:
12:57 PM. North of Saddlebrooke, this cloudburst. With bases as low as they were, LTG, indicative of stronger updrafts in the storms yesterday, likely an inch or more fell in this one. If anyone drove under this with a gauge, I’d like to hear from you, get some ground truth. Also note how obscured this tremendous Cumulonimbus is by the layer of Altocumulus, showing that on really moist days, it doesn’t have to get real hot and sunny to generate big storms.
A little later, this masterpiece of a cloudburst, without doubt one of the most dramatic I have seen in five summers here, or anywhere really. Here’s the sequence:
1:57 PM. Nice looking shower, but kind of so-so at this point. Drifted away from the “action” for about 15 min, and came out, jaw dropped when I saw what had happened over there! You just cannot take you “eye off the ball” here in the summer for even that long without some “volcano” going off. Check out the next shot.2:13 PM, just 16 min later, we have a serious cloudburst over there somewhere near Railway Ranch mining operations next to the Tortolitas. Easily 1-2 inches in 15 minutes kind of rainrate1. Was losing control here and took a lot of shots, just in awe of how nicely shaped it was, the lighting, the lightning, lots of it, feeling lucky to be alive and living here in Catalina and seeing something like this, and on and on. But I had to remember that sights like this are only seconds in duration. So much water is falling out at this second, and smashing into the ground, that the air has to get out of the way, and this columns like these flare out on the sides, and, it can rain out in minutes if the updraft isn’t continued somewhere else. In this case it was on the right side, and new dumps kept falling out as it propagated north. Took some video to prove it, too.2:14 PM. One minute later. Look how the blast at the ground is spreading out already! Unbelievable sight! So pretty, too.2:35 PM. New splash-downs occurred as those dark bases in the earlier photos, representing the updraft portions feeding the storm, gave out, first with fine fibers, if you looked closely, then the whole dump. With each new smash down (does that expression come from wrestling vaudeville?) new updrafts are launched adjacent to the dump and the cycle is (usually) repeated. About this time gusty NW winds from this storm hit Saddlebrooke and Sutherland Heights, but, alas, no new Cumulus formed above it. Must have not been enough of an upward shove, and/or our air too cool.3:05 PM. Eventually, all of those dark Cumulus bases got rained out and no new ones formed, leaving this “debris” cloud to continue raining itself out. At this stage, little if any new precip is forming up there. If you flew in it, what you would find for precip is giant snow flakes, amid lots of other tiny ice crystals, and some residual small cloud droplets, all of which are disappearing. Those large snowflakes melt into normal-sized raindrops (not ones splashing 3 inches off the pavement as would be in the “dump”). The rain here is more and more beginning to resemble the rain that falls in our winter storms. Seeing an absence of new Cumulus near us made me kind of sad at this point after the euphoria and hope just two hours earlier when I thought maybe the outflow winds that roared through would launch new Cumulus over ME. But no, it was all over at this point, with no chance of appreciable rain in “The Heights” (of Sutherland). We did get a sprinkle from a similar dying gasp of a storm that crept over the Catalinas from the east a little later.
Looks like today, absent the latest mod runs and using older material, always a little risky, looks very similar to yesterday, except as yesterday compared to the tropical day before that, our cloud bases are heading upward overall as the level of moisture declines.
Also, like yesterday, there’s very little steering wind for our storms, and so they tend to sit and die, unless the outflow winds can launch new buildups that blow up into Cumulonimbus clouds. Those outflow winds are chaotic, and where that happens, well, you’ll have to be watching. Though Ms. Lemmon, our nearby friend, did not produce much of anything yesterday, you figure that’s going to change today.
The good news ahead is that there is no clear cut end to our summer rain season yet, though there will be greater and lesser days of activity, as usual . Eventually the westerlies aloft will sweep down into Arizona and clear it out once and for all, but that’s not in the cards yet over the next 15 days.
Being Saturday today, NCAA college football day in America, I hope you will be able to separate yourself at least once from the TEEVEE at least once during the day, preferably after 11 AM, to view our too soon-to-end summer clouds. Remember, you can watch football until February 2014, but you only have maybe two weeks more of big Cumulus and Cumulonimbus clouds and lightning spectacles. Think about it.
The End.
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11-2 inches has been measured in hourly recording gauges in 15 minutes here in AZ. When that happens, you don’t have beads of water running off the roof, you have pretty much a solid waterfall.
Maybe they sneaked up because I wasn’t looking. After posting yesterday just after 5 AM, went out side and looked at the Catalina Mountains, that is those parts I could see through the thick rain shafts, and said, “WHAT!!!?” I was STUNNED to see them; had not even looked at the radar imagery for a couple of hours. Really was asleep at the keyboard.
And then the hour or so of rain that followed, with no lightning! Rain is so rare here om the morning in the summer, and it was so substantial. If there was a disappointment, a slight one, it was that Cargodera Canyon (NE corner of Cat State Park) with 0.87 inches, and the bridge at Golder Ranch Dr and Lago del Oro (0.71 inches) got so much more than we did here in Sutherland Heights in the past 24 h (0.38 inches). They were hit harder, too, by that late afternoon Cb that drifted off Pusch Ridge, again, a heavy shaft of rain with no lightning–how often have you seen that in a summer afternoon?
For a roundup of Pima County rainfall totals, go here.
It was, with its high concentrations of drops, a rain reminiscent of coastal Washington State in the early fall when offshore waters are still pretty warm, or Hawaii, for that matter, the latter location where most of the rain forms without ice. Our high concentrations of rain drops was also likely due to forming, at least partly, through the “warm rain” process, one that does not require ice, and is VERY rare in Arizona. Requires really warm cloud bases, and we had them yesterday, with bases around 60 F, 15-16 C, not too much cooler than you would find hovering over you in New Orleans or Miami, or Merida, Mexico, etc., places where warm rain develops routinely along with ice in the deeper clouds.
Here are some scenes from our huge, and low based, soft-looking, “soft serve” Cumulonimbus clouds, ones that looked that way because updrafts are weak for such deep clouds. You will see that updraft weakness in these photos.
This will seem strange, but I thought yesterday, with its absence of thunder until around dark to the NE, was one of the most unusual days I have experienced here in the summer, so reminiscent of the clouds in the Marshall Islands near the Equator that we (the U of Washington’s research aircraft) flew into during a ’99 field project down there; low, warm bases, high visibility under them, and clouds with weak updrafts and little lightning (the plane was only struck twice during the program):
11:44 AM. After the rain, this gentle giant. No anvil, frosty glaciated slides that kind of slope upward, all indicative of relatively gentle updrafts, a situation that limits the amount of electrification that can build up in them. I was in awe of how pretty this was, and how unusual its appearance was, too. Had to stop, jump out in the mud and grab a shot.
11:46 AM. A closer look. I am just beside myself at how tropical this scene is, so I took another shot. Took too many photos yesterday, too.2:31 PM. Another tropical-looking scene on the Samaniego Ridge. Cloud bases are running about 15-17 C here, 59-62 F. Coulda been taken in the hills around Luzon, Phillipines. Note itty bitty rain shaft. Without doubt that from drops colliding and sticking together (“warm-rain process), no ice needed for those clouds to start raining yesterday. I hope you enjoyed this unusual day as much as I did! It was like being transported to a REALLY warm and humid climate, and yet, here we are in a desert!3:06 PM. Maybe the “Dump of the Day”. It was beginning to fade at this point, and as it approached Catalina, I listened intently for thunder, but none was heard. This, too, made it so “tropical oceanic” since those huge clouds with their weak updrafts, hardly ever have lightning. But I have never seen a shaft like this in the afternoon here sans thunder, making the day that bit more unusual, and special. I will never forget you, August 29th, 2013.6:43 PM. Just the condensation of the water, and the accompany release of a little heat was enough even in the evening to send small clouds shooting upward, another sign of warm based clouds. The warmer the base, the more water is contained in the droplets that first form, and the more heat that is given off to the air next to the droplet. Those clouds were magnificent last evening on the Catalinas! There was yet another Cumulonimbus beyond the mountains, too.6:45 PM. Just two minutes later, I was thinking about that curry dish with mushrooms. I guess it shows how flexible the human mind is, going from this to that.
Well, that’s about all we have time for, kids, and the hour of the exede.com choke hold, 5 AM approaches, and its too frustrating to be on the Web after that. May dredge up a Kwajalein shot at some later point, for comparison purposes, though.
——Today——-
Dewpoints are still running very high, even several 70s in the state (68 F here in the Heights). And so, with luck and no drying and no appreciable changes evident, we’ll have another day in the Phillipines, or the Marshall Islands, or Puerto Vallarta, New Orleans, Miami, Panama, etc. Enjoy.
