About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
Author: Art Rangno
Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.
Been kind of sad since the “cold turkey” end of the summer rain season about a week ago, grasses browning now, pig weed wilting.
8:24 AM Saturday, Sept 15th, fubball day, near the back gate of Cat State Park.
Trying to “man up” today. Got happier just now when I saw that the “WRF-‘GOOFUS'” model returned “green pixies” (aka, green pixels indicating areas of rain) to Arizona beginning next Sunday. They stay around for a couple of days, too.
Now, in a disclosure of some kind, I have to tell you that this run from last night’s global data taken at 11 PM, is one of the wetter model indications from the past few days for rain in AZ, Sunday through Tuesday. Some horrible model runs have had NO RAIN whatsoever around these parts.
This is NOT about Cream, the Eric Clapton-led group who did the song, Strange Brew which I allude to in the title, though I did like that song at the time. (The link is hilarious. What were people thinking, dressing like that? And that hair on the expressionless Clapton!)
Yesterday was an interesting day with some gorgeous clouds, some light rainshowers and a tornado–well, not quite–but almost. A long funnel cloud appeared and re-appeared three times in succession over there by the Tortolita Mountains. Since this is the internet and you might not believe me, here is the proof in these photos taken in mid-morning:
9:55 AM. The tube was first noticed. Its interesting that just before that I was thinking, “You know, I think there’ll be a tornado today.”9:59 AM. Getting long and dangly in this second “ejection” downward. Maybe I should call the fire department. Nah, its just one of those rope-like ones like you see in the Florida Keys all the time, hardly more than a big dust devil.
10:00 AM. Getting fatter, but not advancing downward. Yawn…. I wonder if anybody else is noticing this? I mean, screaming here, “Its a friggin’ tornado almost over there!!!! Wake up!!!”
10:05 AM. Tube came out a third time trying to get to the ground in a snake-like pose, trying to scare people, but those bent rope types never last. It was gone in a minute or two after this.
Less sensational, erudite part of today’s yesterday’s rehash
Yesterday we had clouds developing rain by the “warm rain process”; light rain showers that fell from clouds with no ice, except maybe for one maybe that did appear to get a little ice in its top.
The formation of “warm rain”, something that occurs, say, in Hawaii all the time, and along the coasts of the continents, RARELY occurs in Arizona. Cloud bases have to be particularly warm (“check”, 15-17 C, around 60 F) in the morning hours yesterday), the air relatively “clean”, that is, free of much air pollution (“check”, due to rain lately), and perhaps even more importantly, updrafts that at the bottom of the cloud that relatively sluggish (check, weak updrafts only activate the biggest, best cloud condensation nuclei, insuring few and larger drops. I think that was a real contributor yesterday morning). Rarely are our high Cumulus cloud bases warmer than 10 C (49 F).
The last two factors, clean air, weak updrafts at cloud base, mean that the droplet concentrations in the clouds will be low. Low droplet concentrations mean that each itty bitty cloud droplet will carry more water, be larger in size than a cloud with high droplet concentrations in which the condensed water spread on many, many more drops that HAVE to be smaller.
“So whut?”, you say.
Well, when cloud droplets reach sizes between 30-40 microns in diameter, HUGE for drops formed by condensation alone, something rare here, they can bump into each other without bouncing off one another like ping pong balls, but can collide and stay together as one much larger drop (remember Hocking 1959? The reprise, Hocking and Jonas 1970?). Remember, too, that cloud droplets smaller than 30 or so microns have hardly any fall speeds and so those drops just hang around up there not doing anything but trying not to evaporate (“die”).
That larger drop that results from coalescence, then falls much faster, bumps into more of those larger in much more violent collisions, cloud drops and soon is a billion times bigger than a cloud drop. Drizzle, fine drops of thick, misty rain that almost floats in the air, but drifts toward the ground at 1-2 meters per second , about like a walking speed, from Stratus or Stratocumulus clouds is always formed by this process. This in turn tells you something about the drops in the clouds overhead. Tell your friends.
Remember that rain CANNOT form through condensation of water on nuclei alone! Your local weather presenter might assert this unless he/she is quite good and really knows stuff. There HAS to be ice, OR, collisions with coalescence. Sometimes ice AND collisions with coalescence are happening in the same cloud, ones with warm bases but also having high tops, ones above the -5 C, 23 F) level in the atmosphere.
Yesterday, nearly all of our clouds that sprinkled in the morning (a trace here) a bit did not reach above the ice-forming level of -5 C, and certainly, in the opinion-assessment of this eyeball, did not reach the -10 C (14 F) level.
Here is the one top that appeared to have ice in it. Can you find it without an arrow? That would be great, quite an advance for you, since it is pretty hard to see. First the pretty sky with two main clouds, then a close up:
9:40 AM. Twin towers; two Cumulus congestus clouds pile up NW of Catalina on an extraordinarily pretty day.9:40 AM. Closeup of cloud top on the right, the frizzy one.
Extra credit question (answer upside down at bottom of page. Note: it won’t make any difference):
Next, if that was ice in that cloud top, and it was indeed warmer than -10 C, 23 F) what would the ice crystals look like?
Congratulations! If you said “rod-like”, or specifically, “needles” and “sheaths” you have won a copy of the Magono and Lee 1966 classic booklet naming ice crystals!
Rimed needles and/or sheaths (the latter, tube-like crystals, hollow inside) ones that collected water drops on the way down that then froze on them) . These are the ones that make it to the ground because after awhile, they become “graupel” or soft hail, roundish little snowballs in Cumulus and Cumulonimbus clouds.Today?
Today?
AZ mod here has a surprising chance of showers late in the afternoon here. Did not expect that. Fingers crossed for ONE MORE DAY!
Might get a shower today, likely our last day for a summer one, one spawned by all that residual tropical humidity we still have today in our lowest layers. Don’t really have a great chance for rain today, and the whole rest of the month looks dry, but you might see a shaft somewhere off in the distance. That would be nice.
Then it gradually dries out more and more in the days ahead, and, without the high humidities we’ve been immersed in for some months now, we’ll have to suffer through cooler nights, even a cool daytime snap is foretold in the models around the 20th.
Kind of sad when you think about it, because all that green we have been enjoying with our bountiful summer rains (8.91 inches here since July 1st), will be turning brown. Makes me think of that California song that was so popular some decades ago, “All the leaves are gray, and the sky is brown, I went walking for awhile on a winter’s day…”, etc. etc., the song referring to the gray coating of smog on the leaves that fall off trees there.
Here is the radar-derived rain report for the nation for the past 90 days, pretty much mid-June through mid-September (June 11 to September 11). Except where blocked by mountains, radar-derived rainfall amounts are really quite good. Check out those 8-15 inches blobs in southeast Arizona, and along the Mogollon Rim! Cool. What’s best about this period is that it took a huge bite out of some of the nation’s worst droughty areas during this spell, here in AZ, mountains of CO, KS, the Southeast. You can go here to create your own maps of rain. Below that is the AZ radar rain map from Intellicast for just the past WEEK. Its amazing. Check out those 4-8 inches (!) blobs in the south part of the State.
I think I will go walking in the desert this week and say goodbye to all that green because in a couple of weeks a lot of it, our grasses and remaining wildflowers, will be as dry and dead as Mars.
In the meantime, a reprise of yesterday’s clouds in the usual “cloud diary”; the light rain that produced 0.15 inches, somewhat disappointing. No thunder, either. Here are some of the best scenes, to me, anyway:
6:49 AM. Early morning rainband approaches from the S, but weakens and is a “no show” here. At least somebody toward Kitt Peak got some rain.1:38 PM. Sun comes out a bit, creating this upward-surging, imitation-of-whipped-cream, or maybe a big muffin, Cumulus congestus cloud on top of a green Samaniego Ridge and Mt. Lemmon. I wanted to be inside it. No rain was seen to fall from it, however.
1:38 PM. At the same time as the prior shot, a second rainband moves up from the S. This is looking very promising, but why don’t I hear any thunder? Reason to be concerned about how much rain is going to fall from it.
2:03 PM. Still no thunder. Rain not looking all that thick, and the “stratiform” part of this system seems upwind of Catalina, not the part with the thicker shafts. Going into a funk, properly so.
2:33 PM. Its just about over. Here a superb example of the boring Nimbostratus cumulonimbogenitus cloud layer, one still able to produce boring R– (very light rain). I guess any rain is good, so I will stop complaining here. I do like complaining, though. Complaining is fun!
6:37 PM. At least we got a nice sunset out of all those debris clouds left over from the Cumulonimbus ones earlier.
Will be hanging clothes up to dry in the house for extra humidity until July 2013 I suppose.
First, the rain report: 1.73 inches on Samaniego Ridge in the 24 h ending at 3 AM this morning; 0.42 inches here! Fantastic. We’ll keep those watery, glistening rocks on the sides of the Catalinas for a few more days. How nice is that for mid-September? Some rain 24 h totals til 3 AM, catches the early yesterday storm period from some of the Pima County ALERT rain gages (a bit chopped up, sorry):
Today? Lots of incoming stuff, should be another day of major rains! (Maybe our last of the summer season. Enjoy.)
Reviewing yesterday…..
Looks like afternoon but its not; yesterday morning just after dawn:
6:33 AM. Unusual early morning thunderstorm rakes Catalinas. What a great scene for dawn.6:39 AM.
Later that afternoon, after the morning Altocumulus clouds thinned and skies became sunny, there was explosive cloud growth over the Catalinas as the temperature recovered from our pre-dawn rains and clouds. Below, a few shots, the first three showing the transition from Cumulus congestus clouds lacking in ?????? (Answer: ice), to ones just starting to show ice in their tops (which means snow and then rain formation).
Now I am going to transition to tiny thumbnails, so you’ll have to work harder to see what I am talking about. But if you work hard, you might remember it better. Also, to help you, I have added an arrow in one shot, really going that extra mile for you today since usually I am too lazy to do that.
The Cumulus congestus clouds you see in the first couple of photos, though quite pretty, are oriented ALONG the Catalinas, not trailing over us from Mt. Ms. Lemmon. This tells you that should rain develop in these clouds over the Catalinas later on will stay ALONG the Catalinas, and not dribble over this way as it often does. That means incoming storms for us here in Catalina will be to the south, toward Pusch Ridge. Still pretty much the same today, except a bit more toward the right of Pusch Ridge, and toward Twin Peaks.
Below, another example of a cloud photo diary, pretty much like the one you should be keeping:
2:07 PM. After a weak shower around noon, Cumulus congestus rebuild over the Catalinas and kind of just mill around for awhile not doing much, being less than they could be.2:15 PM. Its EIGHT minutes later, and I am getting pretty impatient with these clouds. Sure, they’re looking pretty, but they have nothing in them so far (except droplets).2:24 PM. FINALLY, after being bored by pretty but empty Cumulus congestus clouds with nothing much up top, ICE forms (arrow)!
2:34 PM. Had to wait another TEN minutes for some “content” to show up below this cloud, that fine haze of rain just appearing at the top of Sam Ridge in this photo. Note all the ice/rain trails just above the bottom. Time to think about lightning, too, some real content!2:46 PM. First transition to a Cumulonimbus and a thunderstorm, now maybe two rumbles old, is a weak one, shown by the weak shaft on the left. But what’s that coming out of that base to the right?! Now that’s more like! That far denser shaft on the right shows that the upwind turret has powered upward FAR higher than the one topping the weak thunderstorm. This is gonna be good!4:06 PM. And so it was good. This, one of several outstanding rainshafts that affected Sam Ridge and helped that 1.73 inches total along. No doubt something even a bit higher went unrecorded. Here you can also see the end of the heaviest rain blob about halfway down from the cloud base indicating the original turret up top has dropped all it can and will be dissipating.
This is not a tome about Spinal Tap….(clips here in case you forgot) that legendary, well, mythical, really, band described as “one of England’s loudest.”
If you thought the thunder was exceptionally loud yesterday morning during our “thunderrain”, even for strikes as far as a mile or two so away, as the writer did, it probably was. Sound travels best and away when the atmosphere drops in temperature rapidly as you go up, as it normally does on an Arizona afternoon.
But in yesterday morning’s very-unusual- for-us thunder before 8 AM LST, the temperature did NOT drop very rapidly as one climbed higher above the ground for the first couple of thousand feet. See arrow showing this layer above the ground in the sounding shown below. Under these conditions, the explosions produced by cloud-to-ground lightning, do not travel upward and away so well as they would with a sharp drop in temperature with height, as we have in the afternoons, and so what we hear is incredibly LOUD thunder under these conditions. Yesterday morning’s thunderstorm, no doubt to the glee of remaining Spinal Tap band members, was one of Arizona’s loudest it seemed to me.
This morning we have had another thunderstorm THIS MORNING, astonishingly unusual to have two morning thunderrains in a row, and strikes were again loud. The Tucson sounding this morning is very similar to yesterday’s; this time with an isothermal layer (temperature stays the same as you go up), something that would help trap the sound even better. However, it is not quite as deep, and that, too, would play a role.
Note: lived a couple of miles from I-5 in Seattle. That freeway was “closer” on morning’s with an inversion (say, after a clear sky night, quite unusual in Seattle, of course) and “farther away” without one, say when it was cloudy all night, and no inversion formed.
The rain and cloud report: 0.45 inches here in the past 24 h! Excellent! Fell from these kinds of clouds::::: (I’ve got too many colons already; may as well add a few more for emphasis that there is supposed to be a pause for some kind of surprise or something, anyway that comes next. Besides, as many (“many”, hah!) of you have probably noted, I am a cloud maven, not a language maven.
Here is the surprise, one that I did not even know about until I uploaded the photo below::::::
8:21 AM. Just snappin’ away when I caught this stroke at right. Didn’t even know one had happened since the thunder delayed quite a bit. Kind of a cool shot.
Today?
Just eye-balling the maps and clouds, SOP forecast, looks like more thunderrain is in the bag today. Great!
Check with Bob and the NWS for a real good forecast… I have to go out and VIEW clouds now!
The U of AZ models got pretty excited about yesterday’s rain potential, even the WRF-GFS run AFTER the one I looked at and got me excited about yesterday’s rain potential. The model one that followed the one I saw when posting yesterday’s blog, one that comes out around mid-morning based on 5 AM data, also had a big rain day in these parts. (Sometimes the two runs don’t agree so well, so when they did, it seemed like a “done deal.”) Take a look, for example, at the total rain predicted in that later model run that came out yesterday morning, and take a look at what it thought Mt. Lemmon, would receive in the 24 h ending at midnight last night in this pdf:
Yep, 3-4 inches (!) was to have fallen from the skies on Ms. Lemmon in the 24 h ending at midnight last night. You can also see that we here in Catalina were supposed to see at least half an inch (that greenish area to the west of the orangy area). We got 0.14 inches. Better than zero, though.
Catalina mountains max: 0.55 inches, at White Tail, near Palisades Ranger Station (on the highway to Mt. Lemmon).
Probably as much as half an inch fell “over there” under this sudden late afternoon thunderstorm by Samaniego Ridge shown in the photos below.
Two places, though, one in the Rincons, and once again over in Avra Valley, did get drenched with more than 2 inches yesterday, so large amounts did fall in some areas. Very appropriate for the really warm cloud bases and humidity we have these days.
Today?
That late night model run (based on 11 PM data) has another active day today, though not as active as yesterday. The model thinks showers will roll off the Cat Mountains this morning. Not so sure about that, but surely, there will be some giant clouds around and some tremendous falls of rain here and there with the humidity we have. 69 F dewpoint here now (5 AM) in Catalina. Enjoy, as we know these spectacular rain days are numbered, and sooner or later, the westerlies will creep down here and wash all this humidity away with dry Pacific air, and we’ll start to feel those cooler mornings associated with drier air overhead, that dry air that lets all that night warmth escape into space.
GW moisture factoid
One possible cause about why global warming has pretty much halted over the past 10-15 years (well, up to 2010, anyway, when this paper I am going to mention was published), was that the moisture in the stratosphere (the layer above where clouds and precip form) had declined over the period when the temperature stopped rising. With less moisture up in the stratosphere, more heat was escaping into space from the earth since water vapor is the biggest greenhouse gas of all, and when it changes a little, a lot happens to the radiation characteristics of the earth. This decrease in water vapor “topside” since the late 1990s was enough, it was calculated, to offset the effects of increasing anthropogenic greenhouse gases since then. Whether such a drying will continue, or why it happened, is not known.
This finding was from Susan Solomon’s group, work that appeared in the illustrious journal, Science. Solomon is the scientist that did so much work on explaining the ozone hole in the 1980s.
4:21 PM. Veil-like rain with little gradation (just above trees in foreground) falls from soft-looking bases along Samaniego Ridge. I’m thinking “warm rain” process. With those low (and very warm bases) the scene looks “Hawaiian” to me, a location where ice is rarely involved in the production of all that rain they get there. 4:39 PM. After the rain over there being “veil-like”, a shaft suddenly emerged announcing that a top has shot up at least 10 kft more than the tops around it, has reached the ice-forming level. Lightning is now immiment.4:48 PM. A wall of rain moves slowly off the Catalinas toward Catalina. Only remnants of a once proud line of heavy rainshafts arrive, leaving us with just 0.14 inches.
Dewpoints above dry ground yesterday of about 70 F at 3000 feet elelvation? Yep, that’s just like Florida air if you could be in it at 3,000 feet. And we had Florida-like clouds yesterday, too, with their warm bases, around 15 C (59 F) in the morning–remember how important warm bottoms are for a big rain dump. Warmer cloud bases mean more water up top.
After a couple of grizzily, grudgingly humid days with no rain very close by, we finally got that explosive, much greater coverage of huge Cumulonimbus clouds and some rain yesterday. Only 0.06 inches here though. Oh, well. Lets be happy for well-watered others, if grudgingly.
The cloud signs that the day was going to be very different from the previous two humid “dry” days were there early. The first thunder was heard at 11:45 AM, as one cloud piled into the upper troposphere on top of Mt. Ms. Lemmon just an hour after the first photo below. Those Lemmon drops produced 1.38 inches at the Pima County ALERT gage there, but a Summerhaven private gage reported 2.46 inches after several storms in the afternoon!
10:48 AM. The day ahead is laid out before you. No need to ponder whether giant storms will abound. Very tall, thin clouds like these tell you that the atmosphere is like a stick of dynamite; only the sunny fuse needs to be lit, and that fuse is beginning to be lit. I was beside myself with excitement when several clouds like this jetted upward off the Catalinas yesterday morning, their “warm” bases topping the mountains. As a cloud maven junior, you should have at least mentioned something to a neighbor: “Man, there are going to be some doozies today!”, and he knows you haven’t even checked with the NWS yet.
Pima County rainfall table Most: Avra Valley area, Michigan and Calgary Streets, 2.13 inches.
Later yesterday day, these, a collection of my favorite moments, ones I hope you caught, too. In case you forgot to log these events, I have filled in some appropriate “novella-sized” captions for you. I don’t mind if you copy them down as though you had written them yourself… Also, don’t forget to review the awesome U of AZ time lapse movie here, to fill in any other gaps you might have. Now these photos are going to be kind of scattered around but in that sense, reflect the writer’s eccentricities, and because he hasn’t got time to straighten them out.
11:20 AM. Your log book entry: “First cloud to reach glaciation level, 11:20 AM above Mt Lemmon. I am so excited. This is going to be a fantastic day for clouds.”11:46 AM. Your log book entry: “First thunder now. The earlier Cumulonimbus capillatus cloud has been replaced by this larger one. I bet Lemmon/Summerhaven are getting pounded. Wish I could be there.”12:31 PM. “Mt. Lemmon still getting pounded, but sky brightening, looks like the base has been eroded and is not being replaced, not good. Some rain working its way off Lemmon and Samaniego Ridge, but not making it very far. Maybe it won’t even get to me. Feeling sad.”12:32 PM. “What that over there! I had not seen that while focusing on Ms. Lemmon. That cloud is huge. Look at that base, so firm, so fully packed! This is gonna be a great dump. I wonder if I can get over there in time. Nah, it goes too fast. Looks likes its gonna land on RailX Ranch over.”12:38 PM six minutes later. “Oh yeah, baby, here it comes! Drops and hail as big as cataloupes! Well, I guess in Arizona, we would say, “as big as gourds!”, figuratively speaking.12:41 PM, just THREE minutes later! “Feeling sad again that I am not there under this cloud with my raingauge. Maybe a cloud maven junior is there measuring it, keeping track of the time after getting his gage out in it, maybe see if some record for AZ is going to be set, like more than 2 inches in 15 minutes. I guess I can be happy thinking that someone is over there having a good time in the rain.”12:54 PM. “Rain dump sweeping air out of the way like a big broom. Feeling a little exhausted now as storm reaches peak, likely to fade soon.”
In the meantime, more Cumulonimbus clouds form quickly over the Catalinas, but just as quickly fade, the rain getting closer, but only sprinkles have gotten to Catalina by late afternoon. Then another surprise!
3:13 PM. “Yikes! What’s this coming around Pusch Ridge and out of Tucson? This is incredible-looking! Will set up video, charge camera batteries. No telling how much weather excitement might get to Catalina.”3:33 PM. “Starting to look ‘biblical.’ That’s always good–‘the end is at hand’, at least of the disappointing dry days.’ I can only imagine how excited the cloud maven juniors are getting seeing this scene.”3:40 PM. “The cool outflow wind has struck Sutherland Heights, those lower scud clouds riding on top of it. But where is the solid base needed for a regeneration of a huge dump of rain? I want really want to cuss and say, ‘dammitall’, but I will refrain from doing that. And its looking more stratiformy toward the south, like its dying out. What is happening? Is the main development going to propagate out toward Avra Valley again? Am really starting to feel awful now, that kind of disappointment you feel when your team has a 24 point lead at half time and loses by 12. Still looking ‘biblical’ but with your cloud maven junior skills you know its not looking ‘right’ for a big rain on you.”4:05 PM “It is finished. ‘Biblical’ sky raced by, one associated with outflow winds of that really good storm somewhere else down to the south, and not on me, and it couldn’t push up some new fat bases of clouds that would grow into giant Cumulonimbus clouds as so often happens with the outflow winds. Going home now, kind of dejected. Hoping now we just get any measurable rain. Grasses fading in color now after our dry spell, and suggestion that a new season will soon be here, no more big clouds, adds to dejection and feelings of worthlessness. That’s what a disappointing day can do to you. But as Scarlet said, and we must remember those words, ‘Tomorrow is another day.’ And, we are having some lightning to the west of us here at 4-5 AM. Cool! Getting excited!”
Today?
OK, have spent some silly time here, now, looking out window, bases low on the Catalinas again. Dewpoints very high. Seems like it should erupt again IF the atmos structure above these clouds is anywhere close to yesterday. Let’s see what the best, Bob, has to say here. Oops, he’s not up yet, but he is the true guru of Cumulonimbus and such that we have here. Be sure to check back soon!
Sounding from TUS this morning makes it look like its a “go” for giant clouds again, bases as warm as yesterday, if not a little warmer. Egad, flash flood size.
Finally, U of AZ late night model here also says there’ll be a big day. Charge camera batteries.
While we here in Catalinaland only received a “trace” of rain again from a thunderstorm that sudddenly formed just before 3 PM to our SE-S, there were some tremendous rains in the area yesterday afternoon and evening. Some examples:
Pima County ALERT precip, max observation: 2.09 inches, Brawley Wash at Highway 86
U of AZ rain map, maximum, as of 7 AM (more reports will filter in during the day): 0.90 inches, N Tucson, see this dump in the movies.
Cocorahs, Pima County max, as of 7 AM (more reports will filter in during the day): 0.64 inches, 2.5 WNW Tucson
USGS, Statewide max 1.2 inches, JD Cabin near Williams.
In the meantime, here’s a nice map of radar-derived rainfall, ending at 5 AM today, from the folks at WSI Intellicast:
The most exciting, predictive aspect of the day, that is, how unstable the air over us was, how ready the atmosphere was to allow plumes of cloudy air to shoot upward, is shown in this U of AZ Weather Department action-packed movie which I shall name; “Dancing Rainshafts”, because they do kind of twist around each other in this movie in the late afternoon. One of those is responsible for that 0.90 inches rain in north Tucson around Sky Line Ave. This is one of the most interesting videos I’ve seen. Nothing much happens until late morning, and then, “Pow!”
If you noticed at the beginning of the day, when Cumulus started to form on the Catalinas, you saw these incredible, tall, thin clouds, something akin to smoke stacks, plumes from geyers, rising off them. It was a sure sign the atmosphere would do something special yesterday. You’ll have to see those tall thin clouds in the U of AZ movie; while I did “document” them in a sense, there was no memory flash card in the camera again, the tiny font alerting me to this fact too small for normal vision.
Still, thanks to the U of AZ Cats, who won their football game on Saturday, you can see it here, to repeat.
OK. now on to the local cloudscape yesterday….
Here’s what I thought was a surprise, this sequence where a modest cloud glaciated. Suddenly, after a period of remission in Cumulus activity, this moderately large cloud welled up SE of the house (first photo).
2:49 PM. So-so Cumulus congestus arises to the SE. Am hopeful something will happen, but it doesn’t look so well organized; base a little broken up. I decided to go into the house and think about something else. 2:58 PM. Amazing! That modest guy has glaciated at the top! I am somewhat shocked. As you know, this means a bunch of snow/rain/graupel-soft hail has formed up there. Fantastic! The next two shots illustrate that this happens, most of the time here anyway, just BEFORE rain falls out the bottom.
Also at 2:58 PM looking at cloud base of the glaciating top (far right) to see if there was yet any sign of a filament of rain, though a few very large and sparse drops might have ejected from it by now (under the far right).2:58 PM. As part of a photographic burst, here’s a better view of the bottom of that cloud with the glaciating top. No shafts. Here’s an example where, in a burst of converational meteorology you can amaze your friends by telling them, “There’ll be a heckuva shaft of rain coming out of this cloud in about five to ten minutes.” You’ll be seen as some kind of weather guru. Perhaps you’ll be invited to the next neighborhood party as a result of your new status.3:03 PM. Shaft emerges. There are striations in the cloud above the bottom if you can make them out. That’s all that precip up there finally being unloaded.3:08 PM. The shaft at right, such as it is, is fully developed from that modest Cumulonimbus cloud. Other shafts have developed more rapidly.3:16 PM. The original shaft is just about gone, but look at this coming out! This intensification tells you that a turret had shot upward to far higher levels than the one that started this whole thing off. The shower has drifted to the east, too.
The weather ahead….
More of the same every day for the foreseeable future, which is about a week now. Check here. They have a lightning icon in every 12 h period! Fantastic!
But, with all those percentage chances of rain over that whole given in 12 h increments, what IS the chance of measurable rain here in Catalina at some time during that FIVE days? IF I have calculated it correctly from an example given to me by Mark Albright, Research Meteorologist at the U of WA, it is…drum roll… 96%!
Pattern clouds: Cirrocumulus undulatus in odd, parallel lines. I had not seen parallel lines like this before. Fragments of Altocumulus are also present.
7:55 AM. Hope you saw this–I ran out of the house since these delicate patterns are usually gone in a couple of minutes.12:21 PM. Ms. Mt. Lemmon starts to do her thing, send moist plumes of warmer air upward, with cloud remains trailing off to the NW. A southeast flow is present just above mountain top level, giving hope that later, a thunderstorm will drift off the Catalinas toward Catalina.2:47 PM. Not a great base, but still, it holds promise of representing the bottom of a cloud that can produce measurable rain.3:09 PM. During halftime I am able to go outside and notice that the Cumulus clouds are still trying to do something, but only light, barely visible showers have fallen toward Samaniego Ridge.4:06 PM. After the game was over (which game? Dunno, they’re all great) I am able to go outside again and see that a giant cell has formed dropping an inch or more out there to the NW of Catalina. There are frequent cloud to ground strikes. But, there are no more Cumulus above the Catalinas! What happened? End of rain possibility story.
Though only a few drops hit the ground here in Catalina, the day ended with a pretty sunset. This marked the third day in a row where large Cumuluonimbus clouds cells at least an inch of rain in southern Arizona, but we got missed, something that also happened several times in early August.
Some of the moisture doing this is from old, former tropical storm, Elena, particularly the moist plume that resulted in yesterday’s pretty pattern clouds shown in the first photo. Check the moist plume (whitish stream) from her here.
Looking ahead…..
While Elena was a bit of a disappointment as far as producing rain here in Catalina, her lower level moist plume too far to the west, a sibling storm is arising off Mexico, one that the models (hah!) as they did before, have calculated will cause a renewal of our summer rain season; showers are foretold for several days beginning around the 3rd as that storm trudges up the west coast of Mexico toward Baja. You can see the storm and the showers here in this rendering of the WRF-GFS model by IPS MeteoStar. Remember those green areas on these maps are those in which rain is foretold to have fallen in the previous 6 h (later in the run, in the prior 12 h). There is a LOT of green over SE Arizona after the showers begin to occur by the afternoon of the 3rd.
As is commonly heard these days from people concerned about drought, “think green”!
6:40 PM. A little hole in the clouds allows the late evening sunlight to penetrate into the aerosols we have over us, thereby producing an orange ray of sun.
I guess we can be happy for them… Here’s how the day went.
9:39 AM In case you missed logging this special cloud, Cirrocumulus undulatus, waves in the atmosphere.9:40 AM. I guess you could have been distracted by the first Cumulus rising off Mt. Ms. Lemmon.12:07 PM. Nice progression to our Catalina cloud street off’n Lemmon, but slower to grow than the day before. Reason to be concerned.
3:08 PM. The local picture begins to improve as a Cumulonimbus with a strong rainshaft forms N of Catalina and Cumulus congestus arise away from the Catalinas.4:23 PM. Now this is really looking fantastic! Its going to dump for sure, and while this Cumulus congestus base is to the N of us and moving away, the ensuing outflow winds from the falling rain might well cause clouds to back up against the wind and new heavy Cumulus might form over us!4:33 PM. “Dump, der it is”, paraphrasing the popular ditty from “In Living Color” that emerged at ball games, “Bloop, there it is”… Now, lets see what the outfloiwng wind does. Can it move that dark region this side of the rainshaft thisaway? I sped off to Sutherland Heights district to get a closer, electrifying look.4:43 PM and 20 photos later…. This is looking fantastic, at least, over there by Saddlebrooke.4:50 PM. Someone’s getting ver wet over there. A Pima County ALERT gage reported 1.06 inches under this. But, the dark cloud base on this side has thinned (take a look above the partial rainbow). Its over for Catalina as far as outlfow winds pushing up a new base.5:15 PM. While pretty to look at, the tattered clouds to the left of the rainshaft are telling you “its over.” Now, the only question that remains is whether there will be a nice sunset?6:50 PM. And the answer to the sunset question was yes.
