…says the sky on August 5th, referring to almost the exact same sky as on August 4th at this time. Also, both days had OCNL LTG (texting “occasional lightning” here in weatherspeak) off the to distant NE, unusual for this time of day. Even heard thunder this AM.
Below, which shot is from today, just now, and which boring shot of “stratiform” debris clouds from complexes of Cumulonimbus clouds that have dissipated instead of arriving here full strength boo-hoo is from yesterday?
6:07 AM, August 5th. Altocumulus floccus/castellanus deck with Altostratus cumulonimbogenitus (watch out how you pronounce this in mixed company).
7:00 AM, August 4th. Altocumulus castellanus deck under Altostratus cumulonimbogenitus.
So what’s the routine now? Gradual thinning with isolated showers, ones that also eventually disappear, followed by brighter skies, and growing of Cumulus clouds like desert weeds in July after the first rain. You’ll have noticed by this time that was a cloud scruff (Stratus fractus) on Ms. Lemmon today, indicating that the moisture is enhanced today over yesterday when the bases were appreciably above Ms. Lemmon. So, a better chance of rain, sans any model glimpses, but then since rain was very sparse yesterday, except for that 2 inches that fell in the mountains S of TUS yesterday afternoon (1.61 inches measured at the Florida Canyon Work Center), almost anything would be an enhancement of a rain chance here over yesterday so I have fudged some words here.
What happened to produce all these dense, morning clouds the past two days? Cloud gigantism in northern Mexico last evening and overnight. Must have had a TON of precip in these complexes that just exploded down there, inches of rain no doubt fell. Sure wish we had some reports under these magnificent blow ups. There are quite a few rain measuring stations in Mexico, but that data is not available from remote areas until they’re published. Here’s a view of last night’s Mexican eruption from IPS Meteostar.
!! PM AST U of AZ mod has rain “on the mountain” (the Catalina ones) by 3 PM AST, and, like yesterday strong storms to the south of us heading this way. But, like yesterday afternoons showers down thataway, they don’t make it here, the model reports. You can do the loop for precip here in their rendition of the WRF-GFS mod. Hoping Mr. Leuthold, our U of AZ expert, will shed further light on this when he reports here today between 10 and 11 AM. In the meantime, I am sure convection expert, Bob (Maddox), will have something to say before then.
Not looking that great for a juicy August rain season here in Catalina Sutherland Heights…. Recall last year we had about 8 inches in July and August here, and at the end of August the mountains and grasses were SO green!
The clouds yesterday were supposed to be “splotchy”, big clearings between interesting middle clouds like Altocumulus with long virga strands. Instead there was a vast coverage of Altostratus opacus “dullus” with long streaks of virga, with a few drops reaching the ground here and there but not here. There was some mammatus-t clouds, too. Also, the end of the clouds didn’t get here until after nightfall, not in the afternoon as anticipated from this keyboard.
The result was a much cooler day than expected, too. On TV, they were talkin’ low 80s for yesterday, a reasonable expectation given “splotchy clouds”, but in Catalinaland, it only reached 73 F under the heavy overcast. Very pleasant for being out-of-doors.
Oh, well. Maybe I’ll try building model airplanes and talk about those instead. Or make up historical anecdotes that aren’t true, mixing characters up from different eras and see if anybody notices. Now that would be fun! (Naw. Too silly.)
Here’s your day, beginning just before sunrise when some fabulous, fine-grained Cirrocumulus clouds came over top:
6:31 AM. Finely grained Cirrocumulus (Cc) top of photo, line cloud would also qualify as Cc, though the granulation is larger, still not large enought to be Altocumulus. With a little imagination, the top center cloud appears to be hanging down like those house Christmas lights.Also at 6:31 AM. Here are your splotchy clouds. I can’t believe how good the forecast is going after an hour! There some much ice in the center cloud that you’d have to call it Cirrus spissatus, but an hour ago it was likely an Altocu cas, or floccus, one at very low (not “cold”, to be proper) temperatures.
7:41 AM. Clearings between clouds disappearing! Passing by, and from a thick Altostratus opacus cloud, a display of mammatus/testicularis left center (trying to be even-handed here in cloud nomenclature).
Also at 7:41 AM. More mammatus-t over there, too. My mind has kind of drifted off to mammatus now. Quite nice dispay here. Note: Not associated with thunderstorms, as some urban myths have it. Look, I’m trying to make a dull day interesting. Its hard.1:04 PM. Line of heavy virga from what else, Altostratus opacus, tops at Cirrus levels. Chance of late sun pretty much gone by now. BTW, if you saw a time lapse of mammatus-t clouds, you would see that the “upside down Cumulus turret” look (as in the prior two shots), open up to fibrous little shafts like these.6:50 PM, just before Husky softball defeated No. 2, ASU last night in Tempe, the heart of devil-land. Good sunset, not great, as backside of Altostratus (As) clouds finally comes into view on the horizon. The lower cloud specks at the base of the As layer are those comprised of droplets, not ice, as is the higher As. This shot helps show how different in appearance clouds of the two phases, liquid and ice, are. When they’re together, mixing it up, we call that a “mixed phase” cloud. Because there are so many particles that droplet clouds can form on (typically, in continental settings, there are hundreds of thousands per liter) those clouds have more detail and the drops are too tiny to fall as precip. In the higher Altostratus layer, the concentrations of ice particles that comprise it are probably only in the tens per liter, and those ice crystals/particles are far larger than the droplets in droplet clouds. Most of the ice particles in the As, therefore, are settling downward, evaporating. However, all ice clouds can produce light precipitation to the ground, one of the THREE ways we get precip out of clouds; all ice, mixed phase, and all liquid processes. (Some textbooks I’ve seen only talk about the latter two, BTW.)
If you want, you can go to this loop from the U of WA Huskies Weather Department here and see how the little splotchy cloud thing with that passing upper trough became a big fat thing as it came by. Also in this retrospective, you should examine the U of AZ Weather Department time lapse film. You’ll be amazed at all the stuff going on in a day that looked pretty dull all in all. Also, at the end (after 5 PM AST) you’ll seen the winds aloft change completely in direction as the backside of the trough, the clearing side, approached. I saw stuff I didn’t know was happening. You’ll also see how the mammatus pouches, if I may, open up into fibrous virga. Thank you, U of AZ Weather Department, for posting these great instruction films!
Not expecting clouds for most of today, but will likely see a couple of Cirrus streaming in from the NW late.
The weather ahead
Still no precip in sight, unless you consider lithometeors a form of precip, dust accumulations, that is, such as we had a few days ago. Half inch (of dust) I predicted wasn’t that bad (hahahah). Dust accumulations expected now on the afternoon of the 16th, and again on during the afternoons of the 25th and 26th of April.
C-M alive, local, and… finished with the dust report, now back to the studio.
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.
Wasn’t going to blog, gets boring after a while with only dry conditions ahead, but then saw this and got pretty excited, as you will, too. Might not need that extra cup of joe to get going today.
Its valid for Wednesday, April 17th, at 5 PM AST. Pretty cool, huh?
Its unusual to see a strong signal 312 h from the model start time as here, but especially so as we get later into the spring when the jet stream is slowing down all over the northern hemi and the troughs in it smaller, spaced more closely together, slower moving, too. (Summer is really goofy in that regard.)
Here, both the 00 Z (yellow lines) and 12 Z (gray lines) model runs in the past 24 h are indicating a big fat trough in the Southwest, and the bunching together of the red lines suggest a lot of confidence in that forecast. It would mean another real chance for rain here near this time, plus or minus a day or so.
The weather just ahead, Monday
In the meantime, our very next big trough, cold slam, and stupefyingly large low center, one that explodes from a tiny “Tonopah Low1” early on Monday morning, to one whose circulation extends from southern California to Missouri, virtually covering the entire western US! In spite of its gigantic extent, it still looks dry here, any rain accumulation here very “iffy.”
On the other hand, a half inch of dust accumulation is quite likely since it’ll be darn windy that day, dramatically windy. Likely to see more than 40 mph here in Catalinaland and visibility noticeably reduced in dust later on Monday.
BTW, its quite normal for low centers that are weak over the ocean to erupt into deeper lows as they move inland, during the spring. Just the opposite happens during the deep winter period when ocean lows move inland and weaken or die over the cold continent because they lose the temperature contrast that drives them. In the spring, the warming continent is “food for lows”, like spinach for Popeye (you remember Popeye, don’t you?). Ok, then in more modern terms, like that Hulk guy that got so gigantic when he got mad or something. That’s what happens in the spring to little lows and their troughs when they move inland, especially into the warm Southwest from the Pac NW.
The great news here, and I am so pumped about it, is that this giant low will be a whopper in terms of precip for so many droughty areas of the mountainous West and the central and northern Plains States. Check out the Canadian model here as an example of what’s coming to the Plains States. Just what the weatherman ordered. I’m sure it will make the news.
For reference purposes, a before you, if you will, here is the awful drought situation from the drought monitor folks in Lincoln, NB, in the central and Southwest US as it stands today:
US drought status as of April 2, 2013. Ugh
Yes, this Monday’s low will be a billion dollar baby for some. And here’s where storm chasing is truly fun because of all the happy people you’ll meet in the rainy areas, not like those storm chasers who relish seeing tornadoes and destruction, as might happen farther to the south in Texas and across the South2.
Yesterday’s clouds
Cirrus, thickening into a dull, kind of lifeless layer of Altostratus by late afternoon and evening, the latter a deep all ice cloud; no opening in it to the west for a great big sunset, nope, just gray all the way. Staring with sunrise:
5:59 AM. Cirrus/Cirrostratus over Samaniego Ridge.10:41 AM. Cirrus fibratus (the thicker patches might also be termed spissatus, but who cares? :}) There also appears to be a high thin layer of Cirrostratus. There are definitely multiple layers where clouds are located.6:08 PM. Altostratus opacus. Note the mottled look due to virga, demonstrating that its a precipitating cloud (light snow); just doesn’t get to the ground
Today’s clouds
We’ll see the end of our pretty Cirrus and Altocumulus clouds that we have this morning by mid-day to early afternoon. Enjoy them now. Might get a good sunrise bloom here in a few minutes, too. Hope so.
————— 1Usually located on top of Tonopah, Nevada
2 “Truth-in-packaging”: Mr. Cloud Maven person chased Hurricane Carla in 1961, one of the 20th century’s greatest, ended up in Seabrook, Texas, near Galveston, and let us not forget the song about Galveston (has some wind in it) as a kind of distraction, so he’s being just that tiny bit hypocritical here.
Well, at least much of today anyway. The title for today is from Gershwin, of course, and the version of a song he later changed to “Blue Skies” (really old version here)–this was after he moved from New York, an extremely cloudy state, to southern California (“Hollywood”, in 1936) where weathermen can sleep for six months due to soporifically boring weather, to emphasize that weather aspect there with redundancy since “soporific” means boring as well. I lived there in so. Cal., myself, San Fernando Valley, growing up and I know first hand. Slept out in the backyard with doggie in case a sprinkle fell out of Altocumulus in the summers and didn’t want to miss it1 That’s how bad it was weatherwise.
Continuing, Gershwin didn’t think “Gray Skies” was so uplifting as a song, and he eventually changed the title to something more “accessible” as a popular song (who wants to think about Altostratus, or, Stratocumulus???).
BTW, you won’t find facts like this on other blogs; in fact, to be redundant with the word “fact”, won’t find this kind of information anywhere else at all!
We got us some more of that Altostratus overhead today, and in places, embedded or separate patches of Altocumulus (droplet clouds), and you know what this means. Its snowing up there above 15,000 feet above ground level, and if Ms. Mt. Lemmon was only a few thousand feet higher, there would be PLENTY of snow on top. There could be some spectacular sunrises/sunsets today and tomorrow as this stream of tropical moisture aloft passes by. Be ready.
Yesterday’s clouds
First, a couple of “action” shots, ones where glaciation is taking place:
6:48 AM. You know the drill, (the cloud) used to be this, and now its that. “Droplets to ice; its a natural thing.” The droplet cloud on the right side is Altocumulus perlucidus (looks somewhat like a honeycomb).
6:47 AM. Some more of that over there. Sometimes I have called the icy small patches, “The Ghosts of Perlucidus.” (Happens because the clouds are not only real cold, but damn cold (usually less than -25 C (-13 F).
The weather ahead
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The End.
—————-
1 In case you don’t believe me, maybe I just made that up about sleeping out, only pretending to be some kind of weather fanatic in this blog, this picture for the doubters out there from those summer days with doggie in the backyard; hoping for a drop so I could enter it in my weather diary. Oh, yeah, I had one.
I hope you’re happy now. I put it in full size so that you could see it was me, not someone else.
First, a water year (Oct-Sept) update. You won’t like it:
One caveat about February’s total: It might be as much as 0.25 inches higher since a good bit of snow during the historic February 20th storm probably did not get into the Davis Vantage Pro gage located some six feet above ground level where wind raises havoc with snow measurements in particular. Gauges day had more all around mine. You can go to the U of AZ rainlog.org home, plug in the date (in this case the 20th, and see what other folks had compared to the crummy 0.52 inches the gauge here got following the meltdown. Generally, while there are a couple of goofy obs on the rainlog site, the amounts around here were 0.70 to 0.90 inches. Thus, our February 2013 total is more likely around 1.20 inches, not 0.95 inches as shown in this graph. Dang.
Here’s the March daily measurable rain climo:
Current and just passed weather
Traced last night, I’m sure you logged it. Drops were falling, pretty big ones, at 2:42 AM. Only lasted about a two minutes. If you want to see what happened in radar and clouds, go here. Shouldn’t be surprising that it traced here given all the virga, and isolated spots where drops were already hitting the ground last evening.
Here are some shots after I got back from PHX-Anthem late yesterday. Some drops hit the window, too. First, I thought I would share with you a wildlife response to coming changes in the weather, something you’ll begin to notice as you traverse the long road to cloud maven juniordom. Here, shelled creatures demonstrate a preoccupation with the sky over due to increasing Cirrus cloudiness in Anthem, late on March 2nd, the day BEFORE all the heavy virga. Its something to note when these creatures do this. They are telling you something about the coming weather. Well, anyway, that’s what you should say when you see this turtle formation; your neighbors will then think you’re some kind of turtle “whisperer” AND a weather guru all in one.
At the Anthem Community Park: Wildlife shown here were clearly becoming increasingly concerned about the thickening cloud cover late on the 2nd.
3:53 PM. Tentacles of virga from deep Altostratus clouds reach down toward the Tortolita Mountains.5:53 PM. Altostratus with virga and mammatus (left side), a term reflecting certain female mammalian characteristics. As I have reported here in the past, some of the female grad students at the U of WA weather department were offended by such nomenclature, asking why such clouds couldn’t have have been termed, “testicularis” (quite an unseemly term, really) and drew lines through a label of a wall print of “mammatus” on a fifth floor hallway. The culprit was never caught, and the “graffiti” was never removed. Makes you realize the kind of issues that budding, bright female meteorologists at the U of Washington are thinking about. BTW, this also demonstrates that the notion of “mammatus/testicularis” are always associated with, or indicating a thunderstorm, is quite goofy.6:30 PM. Had a late “bloom” as a distant hole in the overcast let the sun under light our Altostratus clouds with virga. Only lasted a few minutes. Nice.
The weather ahead
Of course, the big media weather stars with their gigantic salaries are all over this next storm, I am sure. Its mind boggling how much money they make having fun with weather on TEEVEE…
Here’s is the latest forecast from our friends in Canada, most of whom want to live here in the good ole USA!; that’s why the entire population of Canada is so clustered near the US border. You can feel them up there (hahah, I like to tease my Canadian relatives):
Valid for 5 AM AST, Friday, March 8th. “Vorticity maximum poised to strike AZ from low over central Cal. “Vorticity maximum”? Cloud and weather maker. There’s some writing on this; hope you can read it.“Bee” sting! LOOK at all the precip indicated for AZ! THis is so great, one of the great model forecasts of our time, well, this winter anyway.
Range of amounts with this next storm: I think in view of the wetting up of the models, I too, will wet it up. Bottom amount, almost surely in the bag, 0.25 inches now, up from 0.10 inches. Top? Wow, in view of passage of this system in the afternoon, you have to think about enhanced convection, thunderstorms here and there, and with those, and luck, the top has to be around 1.00 inches now. Notice how similar the track of this in the Candadian model is to our historic Feb. 20 storm, one in which amounts over half an inch to an inch were the norm. Can’t wait to see this go by, no matter what!
I’m not missing any of this. Its too good. Supposed to rain off and off until the frontal blast about 10 AM -Noon, then clear up for awhile, then scattered showers develop from what will be icy looking Cumulus and small Cumulonimbus clouds, kind of the usual storm chronology we have here. This sequence shown in the U of AZ model run from last night is here, and its been well-predicted by the media weather folk as well. Don’t watch TEEVEE much, but I did catch some bits and pieces by George. It was pretty comprehensive, quite good really, and then I started to feel sad. Why am I doing this, blogging about weather myself when its already out there???????????????????????? Oh, well.
It will be interesting to see if there is more than a few flakes of snow as the front goes by, the rain becomes moderate to briefly heavy, and that’s when the precip will start to have ice in it, maybe turn to snow for awhile due to a diabatic effect where the snow level comes down due to big melting snowflakes dragging it down. An early morning frontal passage would have been better for the best snow accumulation, but, oh, well.
Still looks to be an appreciable amount here, both eyeballing the situation and in the U of AZ mod run from last evening. From this keyboard yesterday, the best estimate for this storm that just kind of popped out was 0.450 inches (the median between a lower limit of 0.20 and upper one of 0.70 inches). Since “we” last wrote, the U of AZ model has increased its precip for us, as though it was affected by something I said. The green “half inch” region has crept that bit closer to Catalina in this latest run below over where it was yesterday.
Accumulated precip for the 24 h ending at midnight tonight.
And we’ll need as much rain as we can squeeze out of this one as the follow up series of storms foretold so long ago in the mods have disappeared–shown during a time when our “truth viewer”, those NOAA spaghetti plots were down for a few days, or they might have tipped us off to be more “circumspect” about a run of storms by showing that they were not reliable predictions. No further rain is forecast for the two weeks after this now! Dang!
The intermittent rain that has been falling is WAY ahead of the front, over there by Yuma as I write at 4:41 AM.
Its developing in the moist flood of air that rushed in overnight at lower levels along with a huge icy shield overhead, no doubt a thick Altostratus with virga on top of Stratocu, maybe dumping some drops into the lower cloud deck. Need more of that.
——————Learning module———————–
The effect of rain drops falling into a lower layer of Stratocu?
If you dropped a cup of water on the top of the layer yourself, the amount coming out the bottom would be more than a cup. Those fast falling drops, about 5-10 meters per second, say for regular raindrops, collide with the itty bitty cloud droplets blowing sideways in the wind. The larger cloud droplets, say bigger than 20 microns in diameter, collide and stick to the fast-falling raindrop, adding to its size. We call this accretion. That bottom kilometer of storms where otherwise “harmless”, non-precipitating Stratocu is likely to be, is critical for appreciable snow and rainfall due to this process in mountainous regions. Almost always, the impression is that its the Stratocu that’s precipitating, but usually its not. So, when you see a raindrop fall, thank a Stratocu deck for making it that bit bigger, thought in some cases to increase precip by 50% due to the effect of accretion in the bottom kilometer (3300 feet).
Might look like this if you could step back to the south of the Catalinas today and draw a crummy cartoon of what was happening, but it was the best you could do at the time
From a 101 class I taught at the U of WA, with modifications to show I am in Catalina, AZ. Background: couldn’t get the real guy to teach that class that summer, and so I was enlisted to do the job at the last minute, thus lowering the accreditation rating of the University of Washington. You see, I have NO ADVANCED degree of any kind, and to have a lecturer without the big Ph. D. means you go DOWN! On the other hand, unlike most faculty at ANY university, I have been asked my opinion on something and was quoted about it in the Wall Street Journal in 2011! Oh, yeah, baby! Wanna spike a football right now! Credentialism; a bunch of hooey (sometimes).
————end of learning module and statement on credentialism aloong with a display of immaturity—————
Back to the storm…. After a couple of light and brief showers, we have amassed 0.01 inches! Only 0.44 inches to go to make a perfect prediction!
Yesterday’s clouds
Kind of a bust, really, and admitting that will make up for some exultations above. Sure, there were some Altocumulus with virga hanging down, but those virga trails needed to be about 20,000 feet longer to be anywhere near where I thought they would be. And then it cleared off almost completely during the afternoon! Oh, well. Pretty day, with lots of wind and mild temperatures. Here are a few shots:
6:55 AM. Altocumulus floccus virgae–has virga. These were up around 20,000 feet above sea level, or about 17,000 feet above ground level here in Catland. Top temperatures with all that ice falling out? About -26 C (-15 F).7:12 AM. Ditto.9:46 AM. More of the same but less.
6:25 PM. After a clear afternoon, a vast shield of Altostratus/Cirrus advances on Catalina.
“Sixteen hundredths”, originally a song by a boy group of that day so long ago, The Crests, about a light rain that fell in May in southern California, an event that is quite rare and exciting at that time of the year there. But then practical and marketing considerations caused the song to be revised to one about candles of all things. How odd. I thought you might like to know some reliable history behind that venerable song, one that made us cry, it was so sweet, and think about, as boys, how much we liked girls when WE were sixteen or so.
Yesterday, while Mr. CMP (“cloud maven person”, but using acronym in trying to be as indirect as possible here) was making some fun of students mixing up units in their calculations of pressure at various heights in the atmosphere, he himself was mixing up cloud “units”, by informing his reader that cumuliform clouds, some dropping graupel, would be seen over Catalina yesterday, not stratiform, sky-covering Altocumulus, followed by great masses of Stratocumulus underneath it, combining later with gray, dank, Altostratus, a scene that finally evolved in the mid-day hours into Nimbostratus with light rain, sometimes with light snow mixed in! Briefly, too, it was ALL “surprise” snow!
The total, 0.16 inches, was also about sixteen times more than CMP thought would fall from that perceived marginal weather producer. (Note: the U of AZ local model’s 11 PM run the night before had it predicted perfectly! However, in some kind of bloated self-evaluation of skill levels, CMP did not consult that model until it was “too late.”) Today, I am quite confident, however, that I really don’t need to look at that model…
What is going on here? Fallibility, I calls it, human fallibility. Remember that old saying about pencils with erasers at the end? So simple and yet, profound.
Oh, well. All’s well that ends well, and the “well” ending was one of a nice little rain mixed with snow (will burn your CMJ tee if you refer to rain mixed with snow as “sleet”!) and beautiful snow down on the Catalinas, so pretty yesterday evening as the clouds lifted.
Today a fine day with small Cumulus clouds, very photogenic again as this kind of wintertime day is here. The mountains should be spectacular, too, due to the cold air that remains that will allow them to be white down low for a few hours this morning.
Precip totals from the U of AZ rainlog.org network here and the national CoCoRahs org here for AZ totals. The measrements at rainlog will indicate that they are for yesterday, the 11th, while the CoCoRahs convention, to assign the rain to the date it was reported, will show the totals for our storm using today’s date, the 12th. You’ll have to wait until about 8-10 AM to get most of the loggers’ reports.
The most I saw in the Pima County gage network was 0.43 inches, an amazing amount, down in Avra Valley. Shocking, really.
BTW, the cloud regime that CMP foresaw for Catalinaland was just to the west of us, around Ajo, AZ, not that far away astronomically speaking. And at sunset yesterday, you could see those Cumulonimbus clouds on the horizon coming into view.
5:53 PM. The forecasted Cumulonimbus clouds for Catalina begin to come into view. I wish I could make this image bigger, maybe in 3-D so you could “feel” this cloud coming at you.
To cry-baby about it a bit more about a missed cloud forecast, this “visible” wavelength satellite image:
1:45 PM AST.
Some un-Cumulus scenes from yesterday:
10:30 AM. Altocumulus perlucidus undulatus and Stratocumulus begin overspreading the sky.11:41 AM. Dark bases of Stratocumulus-Cumulus line up with the wind and head toward Catalina. Virga spews in the distance on the right. Above these clouds was an icy layer of Altostratus.11:58 PM. Mounding tops of Stratocumulus or embedded Cumulus become infected with ice and spew forth virga. Now under this guy, there may well have been a couple of graupel. Above these clouds was an icy layer of Altostratus that helped impregnate the lower Stratocu and Cu with ice, kind of like seeding them.1:17 PM. The lumpy and dark looking bases had disappeared in the virga and snow falling from the thickening Altostratus layer as it became, Nimbostratus. What you’re looking at here is a classic example of snow melting into rain that appears to be the base of the cloud, but its really a transition zone that reveals the snow level.3:14 PM. Snowing hard in Catalina for a few minutes. Here’s what it looks like, coming down at you. Some aggregates of snowflakes were more than an inch across.5:42 PM. The result of our little storm on the Catalina Mountains, Samaniego Ridge.
The weather ahead into March
Gotta ride the storms, ones already predicted as of yesterday here over the latter half of this month. Never good to “yo-yo” on a forecast, as forecasters will tell you.
However, not getting help again in this longer range musing from the NOAA ensembles of spaghetti; site is still down, so riding bareback here so-to-speak, using a western idiom (or is it “idiot”?) In sum, Arizona to end up with above normal precip when whole state considered. This due to being in the bowl, the trough bowl, though breaks in storms, and nice weather, sometimes for several days at a time, will try to fool you into thinking you’re not.
Going farther out on a limb, twig, really, looks like the active storminess will continue well into March. We seem now to have a wet pattern going, though in a desert, its not THAT wet compared to Washington State or elsewhere. Stand by for occasional updates. Am excited for wildflowers now; there may be some!
You will soon notice a nice sunrise with a sky full of clouds, Cirrus-ee ones, Altostratus, some Altocumulus tending toward lenticulars (red denotes cloud forms added after the sun came up and I saw them.)
I am late today, not because I overslept some, but also because I wanted to post a great sunrise photo for you.
You know, its all about YOU again, isn’t it? Maybe you should step back and think about that for a second…ask yourself just where your life is going? Thanks in advance for doing that!
Here is this morning’s nice sunrise, Altostratus clouds with virga:
7:07 AM today.
When you see this morning’s clouds, and the great sunrise, no doubt you will be thinking along the lines of a great sunset today as well.
But you’d be so WRONG!
Using a technique developed here, you can foretell where the back side of today’s band of high and, later, middle clouds will be quite accurately. You won’t need the Titan supercomputer to do it, though it would be nice if you had one. Will reprise that methodology for you:
1. First go to, say, a web site having infrared image loops, such as here in purple and gold Huskyland up there in the wet Pac NW
2. Select a loop that you like that shows the clouds to the west of us, such as the one I have selected for you.
3. Stop the loop at a time period not less than 4 h from the current time (probably best not to exceed 12 h).
4. Get out a Hollerith card (computer punch card), and carefully mark the position of the backside of the cloud band of interest that is upwind of your location, pressing the card hard against your computer montior.
5. Proceed in stepwise fashion to the current time in that satellite loop and mark on the same punch card, the location of the backside of the cloud band. You will now have two “tick” marks denoting the movement of the backside of the clouds over the time period you chose.
6. Now, move the first “tick” mark to the current backside, carefully moving the card along the direction of movement of the band, and pressing it against the computer monitor.
7. The second tick mark you made will now be ahead of the band at a future position and time, based on the time increment you have used.
8. Determine from that future position whether local sunset will occur to the west of the backside while it is still OVERHEAD. If the answer is “yes”, then a tremendous, memorable sunset is likely.
Illustrative example, using an 11 h time increment to enhance difficulty:
Satellite image 1
6 PM yesterday. Cloud band backside is over central California.
Satellite image 2
6 AM this morning. Backside approaching Colo River Valley. But is it moving slow enough to be overhead at 5-6 PM with the big clearing to the west?
Preparation of the Hollerith card; no “hanging chads” here–some people disperse incense now:
Results
The back edge of our cloud band is too far east for a good sunset tonight. New clouds would have to form on the backside for a good sunset. Yes, that COULD happen, and it sometimes does in certain situations, but it probably won’t today. Be thankful for a nice sunrise.
The weather ahead? The cold slam?
Well, every weather presenter is on top of that big time, and so why blather about it here? Of course, tomorrow….”tomorrow is another day” to quote a quote. And after I see how this mostly clear sky sunset prediction turns out.
Chance of early Feb rain still ahead, and I can prove it. This panel below is from last night’s 5 PM AST global data ingest into the WRF-GFS model, our best, as rendered here by IPS MeteoStar. As you can see, there are quite a few acres of rain showing up in southern Arizona on the 5th at 11 AM AST. I’ve added an arrow to help you find it.
What’s gone wrong with the possibilities of a good rain?
A low center is positioning itself off Baja as we speak, in almost exactly the same spot as the one that gave us our drenching rains of a couple of weeks ago. But, like a raggedy-looking hitchhiker that no one picks up, there’s no interaction with this developing low center down there by a trough zipping by in the westerlies to the north of it, one that dips down to the south just that bit and scoots our promising low and all its water to Arizona. Before that happens, that low wanders around and dies a quiet death down there.
When low centers are as far south as this one that is developing off Baja and over the warm waters out there, it’s cool center gradually warms up due to all the Cumulonimbus clouds it spawns, that warm air shooting up into its center and around it, and the circulation around it dies; it gradually just goes away. This is because there is no longer any temperature contrast between the center and regions outside of it, that which drives the circulation: no temperature contrast, no circulation.
Valid at 11 AM AST, February 3rd. This is looking very good, indeed, at this point.
You can see what happens to that low center in the panel above when no trough ejects it right away toward Arizona and it has to survive on its own in the next forecast map below.
Valid for 11 AST, Tuesday, February 5th. I thought I was going to cry when I saw what happened to our promising low and storm. That remnant passing south of Arizona means dense middle and high clouds with a lot of virga, sprinkles, and that’s what the models are seeing in that small area of rain in the first panel. Could be some great sunsets, like yesterday.
Yesterday’s cloud sequence, a classic one we see over and over again
First the thin Cirrus or Cirrostratus. Then, as though a real storm was coming, the sky lowers and thickens up in Altotratus. It non-desert locations, this sequence to Altostratus leads to rain about 70% of the time, that number from ancient cloud observation studies conducted before satellites and models. Finally, the back of the “storm”, well, at 25,000 feet you would’ve have thought is was a “storm” with all the snow that fell on you. Here is the start, middle and end, the latter of our fabulous sunset:
8:03 AM. Cirrostratus fibratus overspreads sky.1:39 PM. Too thick, too much shading to be defined as Cirrus; its now Altostratus. CIrrus typically, from vertically-pointed cloud radar studies, thickens downward to become Altostratus, with cloud tops staying at the same height.
6:01 PM. The backside, the last of the Altostratus clouds, allows the sun to illuminate their undersides, and the light snow that falls from these clouds, only to evaporate here in Arizona.
A look back at our end of January rainstorm
Radar-derived total precipitation from WSI Intellicast for the week ending January 31st, 2013. The Tucson radar was down several times and so our local heavy rains are not shown. But look at what the mountains got SE of Flagstaff, 4-8 inches! So great in this droughtful winter.
