While yesterday did not have the drama of the prior few days, there was aerosol drama anyway, a real battle took place against the forces of evil, represented by air loaded with urban smog, and good, clean air to its north, in which we were initially immersed.
A rare fog bank streamed out of Tucson toward Marana, Continental Ranch, and south Oro Valley and beyond. The moist air near the ground associated with our recent deluge, and capped by an inversion, combined with very light winds allowed fog to form in the first place. Its westward trajectory into the southern reaches of Oro Valley is associated with the normal sloshing of winds in Tucson, from southeast in the morning, to northwest in the afternoon on “undisturbed” days. On most mornings, all we see is a haze layer close to the ground that streaming out of Tucson down that way. In this case, the smog layer was in the form of fog, droplets wreaking with all kinds of untoward particles and chemicals like sulfates, nitrous oxides, hydrocarbons, etc., these from cars, wood burning stoves, factories, etc, all the things associated with modern life in an urban center except for wood burning stoves. As a smog-containing fog, it was pretty, however.
However, most of the time, maybe nine out of ten, that thin smog layer stays south of Catalina, can’t quite get here. But yesterday, the forces of evil resulted in an advance of the smog-fog to Catalina. A southwest wind came up in mid-morning, and like a tidal wave, that low thin layer slurped its way up the Catalina Mountain sides and Oro Valley, rolling over everything, growing deeper as the long absent sun warmed the ground, dissipating the fog, leaving the aerosol contained in it, “naked”, as it were.
It seemed for a time that a slight north wind might rule the day, and the smog would stay south of us as it usually does. Instead an ugly southwest wind developed, as often happens here in the afternoon, as air starts rising off the Catalinas to form Cumulus clouds.
And that’s part of what happened yesterday to bring us smog, besides us being in the protected lee of the Catalinas due to northeast winds aloft. When you’re in the lee, sometimes moisture and aerosols remain trapped there, like those cattails I used to pop open at the north entrance of the University of Washington’s Atmospheric Science Department on days with a strong southwest wind and those seeds would circulate in the lee for maybe an hour in really interesting swirls that could be seen due to all the seeds floating around and around, incoming people waving their arms to get them away because they would stick on your clothes. I was younger then (40s maybe), and I guess it was pretty childish. I’m not like that today, as demonstrated by this blog. I wish I had some cattails today, though.
7:04 AM. Fog streams westward from TUS.7:06 AM. Close up of “sfog” bank. Looks pretty outside, but its not inside. There are people like that, too.7:27 AM. Another close up, almost surreal looking with Kitt Peak Obsy in the background.7:35 AM. If you ever need to get warm, popping up out of the fog and Stratus is a turret due to a heat source over there maybe off Tangerine Road, I-10 area.7:57 AM. It seemed to be a little closer….. Hmmmm.9:44 AM. NO doubt about it, its creeping on cat’s feet toward Catalina! I have never taken so many photos of fog before, too. You could see trees and other prominences disappearing as this smog-laden fog came closer.10:54 AM. The warming air had dissipated the leading edge of the fog, leaving only shreds of Stratus fractus clouds that were coming toward Catalina. But now the the invading smog with it was revealed for all to see, that hazy layer below those clouds along the mountains.11:35 AM. The smog was reaching Catalina, the smog front advancing here along the side of Samaniego Ridge, with almost a little arcus-like Cumulus cloud marking its advance (left of center). It was a profoundly disturbing moment that what seemed like it was going to be a visually pristine day, was now going to be mucked up by some Tucson smog.12:35 PM. Got pretty bad down there by Pusch Ridge, before more heating mixed it up into Cumulus and Stratocumulus clouds topping the Catalinas.Also at 12:35 PM, but looking north into the pristine air that was to the north of the smog bank. This was not clearer looking just due to not seeing aerosols in the back scattering view in which itgs much tougher to see aerosols–they’ll look dark or brown. not whitish. The prior pictures call out areas of smog due to “forward scattering” of the sun’s light toward you by the aerosol particles.
5:24 PM. The sun set amidst the smog and so the light on the mountains had a slightly more orange look. It was still pretty the way the scene was framed by Stratocumulus clouds.5:55 PM. The sun sets amidst a well-loaded aerosol layer, looking orangy-red, and producing the reddish orange cloud base in a polluted Stratocumulus layer. The yellowish orange sky below cloud base, with faint undulations in it, shows that a smog layer is present, and, if you look closely toward the Tucson Mountains at left, you will see the top of the smog layer is becoming visible as an inversion forms, trapping it once again.
a lot….beginning tomorrow afternoon or evening, not today. Today is “pause” day. Also, its trash day today here in Catalina, mentioned here as a public service.
Slow moving, sub-tropical system to drop several inches of water content in rain/snow in mountains, sez our best model, that run by the U of AZ. Thank you, U of AZ, btw. Below a snapshot of the total precip from that 5 PM AST global data crunch, “nested” for AZ. This plodding gigantostorm should keep the water coming down the washes, luxuriate our sprouting wildflowers, some of which, like desert asters, are beginning to emerge and even bloom1:
Total precipitation ending just after midnight, Feb 2nd, as seen by the WRF-GFS model run from 5 PM AST last evening. Catalina/Oro Valley appears to be in a bit of a shadow, so while Ms. Lemmon and vicinity are forecast to get several inches of water content in rain and snow, Catalina gets an inch–though hard to see in this graphic. Why? Likely south to southeast flow coming downslope off the Catalinas. But, I think its WRONG!
Lot’s of gray sky photograph opportunities ahead. Get camera ready. Not much in the way of rain seen in mods after this, so enjoy this rain “chapter” of your life as fully as you can.
Yesterday’s clouds
After another light shower boosted our storm total another 0.02 inches, a fabulous, wonderful, almost Hawaiian like day followed with a little humidity in the air, deep blue skies, and white puffy clouds, ones a true cloud maven would call, Cumulus clouds and would be ashamed if he just said they were “puffy clouds.”
7:34 AM. Sun tried to break through some puffy clouds over the Catalinas after our 0.05 inch shower. A few, very small shower cells were around, but didn’t look like much at this time.7:53 AM. Gee, a strong, though narrow rainshaft developed SSW of Catalina, upwind! Suggests a Cumulonimbus-like protruding, icy-looking top up there on top of the shaft.
8:08 AM. The three amigos rainshafts, headed this way, evnetually dropped another “surprise” 0.02 inches. Earlier model runs had indicated the rain would be over by dawn yesterday.
8:34 AM. One of the “amigos” hit Ms. Lemmon and Sam Ridge nicely. Ms Lemmon racked up 0.59 inches out of the storm overall. Very nice, considering our 0.07 inches total.8:53 AM. As we know so well, sometimes the best, most dramatic shots are those after the rain passes, and the rocky surfaces glisten in a peak of sunlight, here enhanced by crepuscular rays due to the falling rain. A rainbow was also seen, but not by me somehow.
8:54 AM. Closer look at glistening rocks toward the Charouleau Gap.
11:45 AM. The deep blue sky, the puffy clouds topping Sam Ridge, the strong sun, the bit of humidity, the bird flying along on the left, gave the sense of one being in Hawaii I thought.12:32 PM. Puffy clouds still top Samaniego (Sam) Ridge.
2:28 PM. Small puffy clouds provide a “postcard” view of Catalina, Saddlebrooke and environs. Visibility here well over 100 miles. Never get tired of these views! You got some Cirrocumulus up there, too.
2:51 PM. Another postcard view of our beloved Catalina. Rail-X Ranch and the Tortolitas off in the distance, left. Nice patterned Cirrocumulus up top above the little puffy clouds.
5:58 PM. The day ended with a nice sky-filling sunset as a Cirrus layer was lighted from below by the fading sun. The lines of virga show that while Cirrus clouds don’t have a lot of water vapor to work with up there at -40 C (also -40 F), the crystals that form are still large enough to settle out as precip.
The End
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1Desert Aster (I think) in bloom seen on the link trail from the Baby Jesus Trail to the Deer Camp Trail.
Seen on big hike, Jan. 22nd. This plant will be so happy by next week!
1) The quarter inch predicted/hoped for here fell on Borrego Springs, CA, (0.27 inches) instead. So, it was pretty close. We received a measly trace in the past 24 until we got 0.05 inches just now! Barely made the 0.05 inches, thought to be the least that could fall. So, in humility, will be expanding limits of storms, maybe go with 0-5 inches possible amounts for every next storm. Should hit those.
2) Mods still think more rain is ahead over the next few days, beginning on Thursday. This period of rain has always been predicted to be more than yesterday anyway.
3) As an outstanding weather note for my reader, I thought I would post this photo from a friend in Seattle of the exceptionally warm weather for this time of year they had yesterday in Seattle (60s). A young1 woman at Green Lake in Seattle displays how warm it is by dawning a bikini, near where the present writer used to live. “Smells like global warming”, as Seattle’s own Kurt Cobain1 might have said about yesterday, if he wasn’t dead.
While there have been studies about cherry blossoms and that kind of thing coming out earlier in the spring back East of late, maybe there should be one about bikinis coming out earlier, too. How many weeks earlier in spring than during the Little Ice Age, do we see bikinis nowadays? How long has the bikini season been lengthened? Is it commensurate with lengthening of the growing season? That would be a VERY interesting scientific question to address, one that needs to be fully addressed via graphs and photo documentation. Applying for NSF global warming grant monies now…..
Yesterday afternoon at Green Lake in Seattle. A young woman dawns a bikini! Unheard of in January in Seattle! Thought I would display this full size so that you could see how warm it is. Thanks to Bob S, Ballard District, for supplying this datum.
Yesterday’s clouds
8:31 AM. Rainband encroaches from the south horizon. Flow was from the southeast, but movement of band was to the north. The clouds in the foreground are two layers of Altocumulus. The banded rain cloud moving toward us would be Nimbostratus.11:30 AM. Dammitall, its still not here, and now the rain coming out of the band is so slight you can see through to the other side! Nice birds of some kind on the wires, upper left. Makes me think of that Leonard Cohen song, Bird on the Wire, best interpreted by Judy Collins, of course.
11:31 AM. Lotta birds on the wire. I thought you should see this. Above, Altocumulus/Stratocumulus, with a higher layer of Altostratus.4:08 PM. After the trace and clearing, a new bank of Altocumulus/Stratocumulus and rain band approached from the south. Virga can be seen on the horizon, too. Hope building again for measurable rain.4:19 PM. From the corral, a display of Altocumulus/Stratocumulus lenticulars downstream from the Catalinas. Nice lighting on hills, too.4:30 PM. Cloud maven juniors should have noticed that the lower layer of clouds here (left of center), are LOWER than the clouds that passed over earlier. That means the incoming rainband had a better chance of producing measurable rain though it didn’t.4:40 PM. Another great sign that measurable rain was on the doorstep though it didn’t were these faint Cumulonimbus tops showing up beyond Pusch Ridge. Gettin’ excited here, as you were no doubt. Some pretty hard radar cells came up out of Mexico then.
That’s it. No more photos, no rain last night, either, but in some kind of rain miracle, it has just put 0.05 inches in the gauge! So, the forecast from this typewriter that 0.05 inches was the least that could occur in this “storm” has been verified!
Conditions not ripe for much more, though a few light showers are still upwind. Clouds oughta thin as the morning goes along, with huge breaks in the clouds this afternoon.
Mods suggest more rain beginning as early as Thursday night. This one has more potential for rain here, somewhere between 0 and 5 inches, i. e., only a 10% chance of less than zero; less than 10% chance of more than 5 inches. There, that should do it….
The End
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Composer, lead singer for that Seattle band, Nirvana. You can see Kurt in a cloud of smoke singing, “Smells like air pressure here“, a Bill Nye parody of the true Nirvana hit where Cobain sings in a lot of smoke, “Smells like teen spirit.” Compare versions.
Yesterday’s cold front packed a few more rain “calories” than expected…. Kind of wrecked my play on beer in yesterday’s blog title as a way of making fun of it, you know, “Front light”. See rain amounts below.
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But before that, a heads up: 1) More rain on way next week, at least a 100% chance of measurable rain during the week, and more storms after that (people will be complaining before long);
2) there are some pretty cloud photos at the very bottom in case you’d like to skip over a lotta verbiage; quite dull writing, hand-waving, that kind of thing about what happened yesterday.
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Personal weather station totals as of 2 PM AST yesterday as rain ended from the Weather Underground map. The green and yellow areas are radar echoes, yellow the stronger ones.
The official totals are pretty amazing, too, considering our best model was predicting something like 0.01 to 0.10 inches here in Catalina just before the rain started1. Note below the 2.20 inches at Mt. Lemmon. BTW, we’re now just about at our average rainfall total for December here in Catalina of 1.86 inches and we’ve gotten 1.85 inches so far.
Here’s a truncated rain table for our area from the Pima ALERT gauges (its a rolling archive and so you’d better get there early if you want to see the full lineup of totals for yesterday’s storm):
Pima County Regional Flood Control District ALERT System: Precipitation Report Precipitation Report for the following time periods ending at: 04:14:00 12/14/14 (data updated every 15 minutes) Data is preliminary and unedited. —- indicates missing data Gauge 15 1 3 6 24 Name Location ID# minutes hour hours hours hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.00 0.00 0.00 0.00 0.51 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.00 0.00 0.00 0.00 0.55 Oracle Ranger Stati approximately 0.5 mi SW of Oracle 1040 0.00 0.00 0.00 0.00 0.63 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.00 0.00 0.00 0.00 0.55 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.00 0.00 0.00 0.00 0.75 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 0.00 0.00 0.00 0.00 0.67 Cargodera Canyon NE corner of Catalina State Park 1080 0.00 0.00 0.00 0.00 0.59 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke 1100 0.00 0.00 0.00 0.00 0.43 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains 1030 0.00 0.00 0.00 0.00 0.47 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak 1090 0.00 0.00 0.00 0.00 2.20 Mt. Lemmon Mount Lemmon 1110 0.00 0.00 0.00 0.00 0.55 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp 1130 0.00 0.00 0.00 0.00 0.79 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.00 0.00 0.00 0.00 0.71 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.00 0.00 0.00 0.00 1.34 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station 2280 0.00 0.00 0.00 0.00 0.59 Green Mountain Green Mountain 2290 0.00 0.00 0.00 0.00 0.98 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Hell, there wasn’t any rain in the cloud band west of us when I got up, and so I thought with some lifting, and that jet core at 500 mb slipping southward from southern Cal as the day went on, rain would develop farther south in the frontal cloud band. It did, of course, but still thought it would blow through in 2 h or so, something akin to the models as well. The rain fell for about 5 and half hours! The clearing took place a little before sunset, not in the early afternoon as expected.
So what happened?
I think you and I overlooked a disturbance aloft behind the frontal band. It was sliding SEwd fast from Nevada, catching up to our little frontal band. When those things happen, clouds magically seem to be appearing on the backside of the frontal band, fattening it up, holding its progress back; and the rain areas get bigger. The frontal band was MUCH fatter when it went by TUS than it had been just a 100 or so miles to the west at 4 AM AST yesterday morning. Here are contrasting satellite and radar images for two periods yesterday, before the band fattened up and the second, when it was raining so much here:
Satellite and radar imagery for 4:30 AM yesterday. Sneaky backside disturbance is represented by those clouds near Vegas. No rain echoes west of Catalina, stop along the Pima County line making it look like rain will be marginal here.BY 1:30 PM in this satellite image with radar, the band is twice as wide and there’s rain almost all the way down to Mexico way. Look how those clouds and showers near Vegas have caught up with our front, almost attaching themselves to it in north central Arizona. Lots of times this process of upper air disturbances catching up to a front generates a cyclone along the front as the front widens and begins to kink. I think that’s what happened anyway. Whatever. It was a great confluence of events for us here in Catalina. Think how the wildflower seeds are feeling right now with already an average amount of rain for December, and its not half over, and more is on the way, yay!
If you’re a true C-M disciple you noticed something else yesterday: true DRIZZLE in the rain. Drizzle may be even more rare than snow here. And the thick low visibility rain consisting of smallish drops from drizzle sizes, 200-500 microns (a couple to a few human hairs in diameter) and raindrops just above those sizes for much of the time the rain fell, should have made you start thinking of a warm rain process day. Maybe there was no bright band in the radar imagery during those times, something that happens when rain is ONLY formed by colliding drops that get big enough to fall out; no ice nowhere. In the heavier rains, sometimes when visibility was improved, ice was very likely involved.
The TUS sounding really can’t shed light on this question since the morning was had shallow clouds that weren’t raining yet, tops barely below freezing, and the 5 PM AST sounding, with tops at -10 C (14 F), was a little too late, though that layer that was sampled did produce what appeared to be ice virga in the direction of TUS about the time of the sounding. BTW, its well known that “warm” rain processes that don’t involve ice occur at temperatures below freezing, so the expression is a bit of an oxymoron.
So, without radar imagery over us during the time of the thick rain and drizzle, we can’t say for sure, but it sure looked like it to C-M, which is what you should think as well I think. Thanks in advance for thinking what I think.
Enough of my excuses2, let’s rock and roll with yesterday’s clouds
Your cloud day
7:35 AM. Light rain, looking suspiciously like “warm” rain, clouds not looking so deep, spreads over the Catalinas. Its only gonna get better from here as frontal band leading edge is just across the street over there on the Tortolitas.
8:09 AM. “Oh, what a crummy front, things breaking up already”, you were thinking. Also, “Look at how shallow those clouds are! Terrible.” Sometimes these brief thin spots or clearings are called, “sucker holes.” Hope you didn’t fall for it like I did. (Just kidding.)9:43 AM. W0X1/2 R–F (text for “indefinite ceiling, zero, sky obscured, visibility 1/2 statute mile in very light rain and fog”), rain has piled up to 0.10 inches by this time. But you notice there’s something different about the rain; , its thicker, small thick drops hardly making a splash in puddles, even drizzle drops in it. You begin ask, “Could this be a solely warm rain event?” I think so. Note disappearing telephone poles.12:46 PM. After several hours of rain, flood waters begin to appear. Note mottled surface of this small rain-formed lake, showing that the drops were making good splashes at this time. Rain intensity deemed R (moderate) then. Deemed not a warm process rain at this time due to those drop sizes and less bunching, fewer small drops in between the larger ones, visibility was about 2 miles in rain.
The best scenes of all were when the clouds began to part in the late afternoon and evening sun. I hope you caught these beautiful scenes:
The End
—————————————————– 1Total rain prediction from our best model, the one from the U of AZ with the predicted totals through 3 PM AST yesterday. The model run was at 11 PM AST the evening just before the rain began:
The arrow points to our location, in which only a tiny amount of rain was predicted. Mod doesn’t miss very often by this much, but the earlier December storm had the same mod problem, too little in the model compared to what actually fell here. Gee, new thought… Could it be a poor representation of the warm rain process? Hmmmm.
2Your Catalina C-M did have a correct range of amounts that could fall in yesterday’s storm right up until the last minute. For weeks he was predicting, and staying firm with, 0.15 inches on the bottom, and a voluptuous, if that’s the right word, 0.80 inches potential on the top.
Here’s your cloud day for yesterday, a fairly complex day for your cloud diary entries:
7:27 AM. Looking SW along Equestrian Trail Road; Altocu with Cirrostratus above.7:45 AM. Altocumulus perlucidus over the Catalinas.12:38 PM. Stratocu begin to move in under the Altocumulus layer.2:47 PM. Altocumulus lenticularis began appearing, suggesting strengthening winds aloft. This was an odd location for such clouds, perhaps responding to uplift ahead of the Catalinas. Haven’t looked at Froude or Richardson numbers, though, to see if this is reasonable hand-waving.3:02 PM. Looking NNW at Stratocu (“the boring”; is State Cloud of Washington, and Oregon, for that matter) with a little Altocu on top.
4:33 PM. Stratocu. Kind of characterized the dull, dark, late afternoon and evening hours.
Intermittent R- to R– expected during the day today. Hoping for a quarter inch (forecast to friends early yesterday morning, 0.225 inches; will be ecstatic if more falls. Latest AZ mod has about that amount here, and over half an inch in the Catalinas. Usually, though, those amounts are on the high side. On the other hand, if the details about where the the rain band shown below are off a bit, we could do far better than the 0.10 to 0.25 inches predicted. Here’s the accumulated precip predicted for today from that model:
Accumulated rain until 10 PM AST tonight from the U of AZ model run at 11 PM AST, the latest. Much needed, nice heavy band of rain across AZ!
Next rain threat continues for the 12th, plus or minus a day.
Of course, only CLOUDS can rain, so the title is a little silly, but it sounded more dramatic like that. This is the first measurable rain, it fell between 9 and 10 PM here, in EIGHT weeks!
And you could sure smell that special fragrance from the ground and desert vegetation as soon as you stepped outside to do your exercises this morning!
Nice sunrise yesterday morning to start the day. In case you missed, of course, I am there for you.
BTW, in the captions below, I have included for you a discussion of climate issues in a kind of stream-of-consciousness format. OK, its a rant that came upon me out of the blue. CM sometimes gets mad and loses control for a few seconds; need to get some counseling maybe…
6:56 AM. Altocumulus perlucidus. Say no more. Might be a lenticular sort of on the right. Not the classic almond shape, but it did hang on for a long time in that spot. Say no more.
Kind of gray after that in Altostratus with an undercutting, lower layer of Altocumulus by mid-afternoon darkening the sky up some more. Some virga here and there with sprinkles-its-not-drizzle reaching the ground by late afternoon in the Catalina area. Here is your cloudscape for later in the day, very Seattle like during approaching storms that actually rain lightly on you for hours:
10:35 AM. Classic Altostratus translucidus, ice path in cloud all the way to the sun.10:39 AM, after walk down a slope to give YOU a view to the southwest, classic Altostratus as seen when not looking toward the sun. Hard to tell if its translucidus or opacus looking this way. By the way, even when you can see the sun, As clouds are thousands of feet thick, tops usually at Cirrus clouds levels.1:26 PM. Here come the lower, flocculent masses of Altocumulus clouds, ones composed of droplets.3:15 PM. It was all downhill for cloud bottoms after the Altocumulus moved in. Now, the bottoms are lumpy and much larger, casting them as Stratocumulus. There was some virga and very light rainshowers reaching the ground at this time, too. A few drops fell at 3:11 PM. Only the great cloud mavens of all time would have noticed. Lasted maybe one minute.3:15 PM again. Lot going on here, so I thought I would point out some things on a gray day, in particular for my fellow meteorologist Mark A at the U of WA who winters in the Tuscon smog plume. Mark is a super sleuth when it comes to snowpacks, but maybe doesn’t have so much moxie when it comes to smog. Mark, as you know may now, was fired as Assist State Climo for Washington when he demonstrated and kept complaining, along with two faculty members, that the claims of gigantic snowpack losses due to global warming (now repackaged as “climate change1“) in the Cascade Mountains were hugely exaggerated, likely the result of cherry picking a cold snowy beginning and ending with a run of El Nino winters, ones that lead to less snowpack in the Cascades of Washington and Oregon. Such cherry-picking led to a wonderful suggestion of huge declines that has led to a bounty of funding and continued employment, promotions, accolades, citations by Big Media, etc, because such claims, even if exaggerated and untrue, are what we want to hear! And, no one ever got a job for claiming they can’t find any sign of global warming, or only a little one, but rather are vilified for even suggesting exaggerations in the “global warming” domain. Mark, BTW, continuing his sleuthing has recently shown that similar claims for declines in snowpacks in Montana near Glacier National Park, have not been decreasing but rather increasing. He’ll get HELL for this one! So, more vilification is likely ahead for poor Mark, as well as more smog.
What’s ahead, besides the Big Pac 12 Fubball Game on Friday evening?
More clouds. Maybe a few more sprinkles especially tomorrow after dawn. See nice map below from the U of WA Dept of Atmospheric Meteorology (original colors on the map below by that big troublemaker, Mark Albright)
Valid for 8 AM AST, tomorrow morning, which is Thursday, in case you’ve lost count of the days of the week. The arrow denotes an upper level trough, or bend in the winds. Ahead of the bend (sometimes referred to as vorticity, or curling air, or red curly air) the air tends to rise producing cloud sheets, whereas behind red curly air, the air descends. See Seymour Hess, Introduction to Theoretical Meteorology, 1959, Florida State University Press. As you can see by the arrow, that slight bend in the winds is about to pass over your house in Catalina, and the U of Az model output from last evening sees a little rain here with that passage. Yay! Also note suggestion of bifurcated jet flow with a minor maximum in wind (slight bunching of contours) to the south of us, nearly always required for rain here in the cool season.
Here we go…..some pretty, but also dull, photos, along with some novella-sized captions as mind wandered into the obtuse while writing them.
6:44 AM. Nice sunrise due to Altostratus/Cirrus ice clouds.2:00 PM. Kind of a dull day yesterday, kind of like this blog. Stratocumulus (Sc) clouds topped Samaniego Ridge most of the day, below that gray Altostratus ice cloud layer. But those Sc clouds were too warm to have ice in them, and droplets were too small to collide, stick together, and form misty drizzle. Have to get to at least 30 microns in diameter before they stick to one another. Misty drizzle? Could be a great name for a late night female vocalist doing earthy songs like Earthy Kitt back in the ’50s. “Earthy” was much hotter than global warming.3:29 PM. An Altostratus translucidus to opacus, mostly ice-cloud with a dark patch of Altocumulus droplet cloud blocking the sun. If you look closely, (upper center) you can see a that there’s this Altotratus layer may be topped by a Altocumulus perlucidus droplet cloud layer. Yes, droplet clouds at the top of As where the temperature is lowest? Yep, this counter-intuitive finding happens all the time, up to about -30 C -35 C. Been there, measured that; in aircraft research. Ma Nature likes to form a drop and have it freeze before forming an ice crystal directly from the water vapor.4:40 PM, shot taken as we entered a local restaurant. You’ve got your two layers of Altocumulus, with some Altostratus translucidus above those, filling in the gaps. Gaps? Huh. I am reminded that I have a failed manuscript about “gaps”, these kind; Cloud Seeding and the Journal Barriers to Faulty Claims: Closing the Gaps., rejected by the Bull. Amer. Meteor. Soc. way back in ’99. It was an instruction manual, in a sense, about how to prevent all the bogus cloud seeding literature that got published in the 1960s through 1980s, and was not only published, but cited by our highest national panels and experts, like the National Academy of Sciences. Amazing, but true. I give examples. You can read about this chapter of science in Cotton and Pielke, 2007, “Human Impacts on Weather and Climate”, Cambridge U. Press, a highly recommended book. That cloud seeding distortion of cloud seeding science was due to many factors, of which perhaps the primary one was, “nobody ever got a job saying cloud seeding doesn’t work1.” This was a great segue. Of course, we have similar stresses on those researchers looking for effects of global warming nee “climate change” now days. Nobody will ever get a job (a renewed grant) saying they can’t find evidence of global warming, “Can I have some more of that money to keep looking?” And beware the “Ides of March” if you criticize published work in that domain! Think of poor Judy C , a heroine to me, and how she’s been vilified for questioning climate things.
5:29 PM, took leave from Indian food there in R Vistoso for this. Its not just anyone who would excuse himself from dinner to do something other than visit the laboratory.
That’s about it. No use talking about the rain ahead again. Seems to be a couple chances between the 20th and the 30th.
The End
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1You can make a cloud snow a little by seeding it with dry ice or silver iodide. This has been shown since the earliest days of experiments. Below, to demonstrate this, an aircraft inadvertently “seeded” this Altocumulus cloud layer. However, whether the small amount that falls out from previously non-precipitating clouds is economically viable is not known. Increasing precipitation due to seeding when the clouds are already snowing/raining has not been satisfactorily proven. As prize-winning stat man, Jerzy Neyman, U of Cal Berkeley Golden Bears Stat Lab would tell you, you need a randomized experiment and followed by a second one that confirms the original results, with measurements made by those who have no idea what days are seeded and evaluations done by those who have no vested interest in cloud seeding. Wow there’s a lot of boring information here. Getting a little worked up here, too.
Ice canal in supercooled Altocumulus clouds over Seattle, bases -23 C, tops -25 C (from PIREPS). Photo by the Arthur.
The “perfect storm”? Well, maybe the perfect rain, and it kept giving fro several hours yesterday after our best model said it should end yesterday before 11 AM. And what a nice rain! 1.18 inches total here in Sutherland Heights, as measured by a CoCoRahs plastic 4 inch gauge. (You might consider getting one, btw, or one from the U of A’s rainlog.org)
Went down to the CDO and Sutherland Washes to see what was up after seeing the gargantuan 4.96 inch total on Ms. Lemmon, and the 3.62 inches at the Samaniego Peak gauge. Below is the resul for the Sutherland, both were the same, nary a drop in them:
8:15 AM. Looking upstream in the Sutherland Wash at the back gate of Catalina State Park. I could hardly believe that there was no flow with so much rain having fallen in Catalinas! But it was good in a sense; all that rain mostly soaked in.
6:37 AM. A photo of drizzle falling from Stratocumulus clouds. Hope you got out and jumped around in our rare drizzle occurrence. Big hat, no bicycle, works in drizzle, too, the tiny drops won’t get on your glasses. Note how uniform the fuzziness is toward Catalina/Oro Valley, only gradually thickens to the left. Took about 2 h to get a hundredth when this was going on.
7:23 AM. Drizzle drops as seen by your car’s windshield after about 1 sec at 1 mph. Note how close together they are. The tiny drops and how close together they are is what differentiates true drizzle from the phony labeling of spares large drops as “drizzle” we sometimes get from our TEEVEEs by semi-pro meteorologists. Sorry to bang on them again, but REALLY, folks, they should know better. Sure, I’m a drizzle-head, but it really does matter since its a whole different process that produces drizzle compared to sparse large drops. Sorry, too, for another mini-harangue on this, but REALLY folks, we should know the difference! Feeling better now, got that out.
8:02 AM. Heading down to the Sutherland Wash on Golder Ranch Drive with temperatures and dewpoints in the mid-60s, there really was a feel for being on the wet side of the Hawaiian Islands, maybe above Hilo, HI, at 3,000 feet elevation, except for the dead grasses.10:20 AM. One of the many dramatic scenes yestserday, this one looking toward the Charouleau Gap NE of Catalina.10:19 AM. While it was nice to see all the water glinting off the rocks on the side of Samaniego Ridge, a deeply troubling aspect was the amount of aerosol that had moved in suddenly it seemed, evident in the crespuscular rays. How could it be this dirty so soon? Seems like a weather oxymoron after such a long period of rain. Also, one wondered if this aerosol loading would stop the warm rain process by providing too many, and smaller droplets in our clouds. Fortunately, that did not happen, and what appeared to be warm rain events, or ice formation at relatively high temperatures in our clouds, also requiring extra large cloud droplets, for the most part, continued intermittently into mid-afternoon.
10:32 AM. Close up of aerosols and sun glints on wet rocks.
12:23 PM. Glimpse of ice-forming top (smooth region above crinkly top). Types of crystals visible here? Needles and hollow sheaths because the top temperature was likely equal to or warmer than -10 C (14 F) and cooler than -4 C, and that is the temperature range that those crystals form under when there is water saturation, as there is in a Cumulus turret before it glaciates. OK, a lot of hand waving, but that’s what I think and I am here mainly to tell you what to think, too.
5:36 PM. The day ended quietly with a little, but pretty scruff of orographic Stratocumulus castellanus on Sam Ridge, the clouds mashed down by the subsiding air at the rear of our little trough that went by yesterday afternoon.
The weather WAY ahead, too far ahead to even speculate about:
NOAA spaghetti plots still suggesting a pretty good chance of rain here around the 23-25th of this month. Nothing before then.
Looked for a time that the rain might be over by mid-afternoon and early evening here in Catalina with only a disappointing 0.40 inches here, but the rains kept coming overnight, piling up a nice 0.98 inches 24 h total for the storm. In the meantime, Ms. Mt. Lemmon has gotten 4.29 inches! Check out these eye-popping totals from the Pima County network, ending at 7 AM AST today (just updated. These are so great in view of last October’s trace of rain:
Gauge 15 1 3 6 24 Name Location
ID# minutes hour hours hours hours
—- —- —- —- —- —- —————– ———————
Catalina Area
1010 0.00 0.00 0.00 0.24 0.71 Golder Ranch Horseshoe Bend Rd in Saddlebrooke
1020 0.00 0.04 0.04 0.28 1.06 Oracle Ranger Stati approximately 0.5 mi SW of Oracle
1040 0.00 0.08 0.12 0.43 0.94 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway
1050 0.00 0.16 0.20 0.67 1.26 Cherry Spring approximately 1.5 mi W of Charouleau Gap
1060 0.04 0.16 0.20 0.83 1.93 Pig Spring approximately 1.1 mi NE of Charouleau Gap
1070 0.00 0.08 0.20 0.59 1.14 Cargodera Canyon NE corner of Catalina State Park
1080 0.00 0.00 0.00 0.31 0.91 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke
1100 0.00 0.12 0.28 0.55 1.06 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains
1030 0.00 0.04 0.08 0.55 1.57 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak
1090 0.08 0.31 0.67 1.42 4.96 Mt. Lemmon Mount Lemmon
1110 0.04 0.12 0.12 0.71 1.61 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp
1130 0.00 0.24 0.47 1.89 3.46 Samaniego Peak Samaniego Peak on Samaniego Ridge
1140 0.04 0.12 0.24 0.39 1.73 Dan Saddle Dan Saddle on Oracle Ridge
2150 0.08 0.12 0.28 1.14 3.50 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station
2280 0.00 0.04 0.12 0.31 1.93 Green Mountain Green Mountain
2290 0.04 0.08 0.20 0.75 2.40 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Misty drizzle with very low visibilities is still falling here in Sutherland Heights, Catalina, at 3 AM. The Catalina Mountains are not visible from just a couple of miles away. This suggests the clouds overhead are now “clean and shallow” and rain is forming via collisions of cloud drops with coalescence rather than because of ice in the overhead clouds, often called “warm rain,” a rare occurrence in Arizona. You’ll definitely want to log this in your cloud diary!
“Clean” means that the clouds have low droplet concentrations, viz., are not choked with anthro and natural “continental” aerosols but are more “maritime”, almost oceanic in composition, something that easily leads to “warm rain/drizzle” formation. In oceanic clouds far from pollution sources droplet concenrations usually are less than 100 cm-3. They average about 60 cm-3 in Cumulus clouds in onshore flow along the Washington coast, as an example. Cloud appearance should look a little different to the discerning eye, too. With low droplet concentrations, the clouds appear “softer” than usual, not a hard.
Normally, our clouds likely have a few hundred per cm-3 or more and appear darker from below since higher droplet concentrations is also associated with bouncing more sunlight off the top of the cloud1.
With vort max (aka, curly, or curling, air) still well to the west of us at this time (3 AM AST) as seen here. This sat imagery also shows plenty of shallow clouds upwind of us, so it seems like the very light rain and drizzle will continue well into the morning, likely adding a few more hundredths to our generous totals. Remember that the air likes to slide upward as curly air approaches, that is, produce a lot clouds, and today, a last bit of precip. Did pretty good last night, too!
Honestly, you really want to get out and experience our misty, drizzly rain (drop sizes mostly between 200 and 500 microns in diameter; a few human hair widths), before it ends; the kind of precipitation that makes riding a bicycle even with a big hat impossible. You might even try the near impossible trick of photographing the drizzle drops, too, as they land in puddles, see if you can catch the tiny disturbance made by drizzle drops. That would be great photo! I know, too, that experiencing real drizzle will give you a bit of a chuckle as you think of all those less informed folks, some of whom are even on TEEVEE, who call a sparse fall of raindrops, “drizzle.” Oh, my, WHAT has happened to our weather education?!
Yesterday’s clouds
Lots of gray cloud scenery yesterday, including a stunning example of Nimbostratus (Ns), the steady rainmaker (at least here we had that, anyway.) In other places, Cumulonimbus clouds were also contained within that rainy cloud mass and dumping an inch or so in an hour in TUS with LTG (weather text for “lightning2“), as you likely know. Didn’t hear thunder here, but coulda happened since I was off to the new Whole Foods market at Ina and Oracle as the steady rain from Ns moved in it because it said online that they had Brother Bru Bru’s African Hot Sauce which I had been looking for for a long time but when I got there they didn’t have it! The grocery manager apologized profusely and then we started talking about haloes and the ice crystals that cause them. So, you never know when your cloud mavenhood will come in handy in everyday conversations, maybe make that friend you’ve been looking for:
7:14 AM. The many layered remnants and distant rain creeping toward Catalina from the southwest are evident soon after dawn
7:34 AM. New round of rain begins on the Catalinas. Shafting here implies mounding cumuliform turrets on top, likely glaciating. From up there they would probably look like soft Cumulonimbus capillatus clouds, ones with weak updrafts.
8:34 AM. One of the prettiest sights around here can be just a tiny little cloud (Stratus fractus) like this one when a glint of sun falls upon it. It looked so CUTE! Imagine, you could be up on that little knob and run in and out of it, maybe play hide and seek with your friends, except that being a “clean” cloud, the visibility would be pretty good inside it, not like the shallow, impenetrable fogs you sometimes get around Bakersfield, CA. There, in one of those, you could play really great hide and seek! I’m guessing that if you’re reading this far, you may not have a lot of friends. :}1:23 PM. In the midst of our mid-day light rain, a clear example of Nimbostratus with underlying Stratus fractus and Stratocumulus. Remember, its not the LOW clouds that are raining, its the deep Ns layer above them. However, it is OFTEN true that the lower clouds ADD to the rain because as the rain falls from the Ns layer, those drops often collide with the floating drops in the lower clouds thus making a raindrop bigger. That’s one main reason why rain and snow are so much more on the upslope side of mountains just due to that collection of non-precipitating cloud drops! Its so cool! Away from mountains, you likely won’t have so many low clouds at the bottom of Ns, and the rain is less.
2:50 PM. After the rain ended, suddenly this lower cloud line formed representing a wind puff from the west. It headed toward the Catalinas, but then, within a few minutes, pooped out with no precip having fallen out. It was quite a bit fatter before this photo, too. That dissipation indicated that whatever wind source had produced had died out. But anyway, when you see a cloud line like this, think “windshift.”
4:57 PM. Expansive deck of Stratocumulus with spots of very light rain in the distance promises, along with the curly air feature (an upper level vortex) being so far to the west of us at this point, promises that the rain is not over.
The weather way ahead
Dry for almost two weeks. However, a crazy NOAA spaghetti factory plot suggests rain in about two weeks, around the 23-25th, as you can plainly see here:
NOAA spaghetti factory plot (aka, “Lorenz plot”, after chaos scientist, Edward N. Lorenz–he would really like THIS plot!) valid for 5 PM AST Oct 23rd. Rain is hinted at by the loopy lines in Arizona dipping down to the south. Will keep you posted on that, but not very often.
The End. Its really amazing how much information I have passed along today! Most of it correct, too!
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cCoCoRahs gauge, not Davis tipping bucket which seems to have a problem of late.
1This is the concept behind kooky schemes to defeat potential global warming which hasn’t happened for 18 years or so by polluting oceanic clouds, making them “brighter” on top, darker on the bottom by inserting extra aerosols into them. Ghastly thought! Haven’t we polluted enough?
2Recall that weathermen and women were WAY out in front when it came to what we now call “texting”, as in “2KOLD4me” that kind of thing.
Let me give you an example from the 50s when we were rocking around the clock: “M8BKN15OVC2R-F68/661713G24989 R-OCNLY R”, a text phrase that would take a paragraph to unravel, to paraphrase language maven, Noam C3,4., except in those days we had our own private symbols which I can’t duplicate for “BKN” (a circle with two vertical parallel lines in it) and “OVC” (a circle with a plus sign in it). Weather typewriters and teletypes came with those private symbols!
3Wow, a footnote in a bunch of footnotes! Breaking ground again I think! What Noam C. said: “takes a phrase to tell a lie; a paragraph to unravel it.”
4Factoid, one not having to do with weather: Language maven, NC, really liked Pol Pot and his “restructuring” of society back then until he learned about all the millions of skulls were piling up along with that “restructuring.” You can hear about Pol Pot (and hypocrisy) here in Holiday in Cambodia, one of the defining songs of the 1980s IMO, as interpreted by The Dead Kennedys featuring lead singer, Jello Biafra. (You remember Jello don’t you? Ran for president a while back. Kind of surprised we didn’t elect him…)
The sky was packed with tropical Cumulus congestus and a few Cumulonimbus clouds in the distance at dawn yesterday, an unusual sight for Catlanders. A few of those Cu around the Catalina/Saddlebrooke/Oro Valley area grew overhead into “soft-serve” Cumulonimbus clouds with heavy, tropical-feeling showers you could hike in with great comfort; no lightning/thunder observed.
Up to an inch likely fell out of the core of the largest ones yesterday morning, but only .09 inches was recorded here in the Sutherland Heights. The Golder Ranch Drive bridge at Lago del Oro got 0.28 inches, Horseshoe Bend in Saddlebrooke near one core got 0.71 inches, Oracle, a half inch. Due to the exceptionally warm cloud bases, about 60 F again, warm-rain processes were certainly involved with those showers, though glaciated tops were usually seen, too. In warm base situations, they can act together.
Now here’s something interesting of me to pass along to you, something you might want to pass along to your friends when the opportunity arises: ice doesn’t seem to make much difference in the rainfall rates of true tropical clouds in pristine areas, only a little “juicier” than the ones that we had yesterday. Early radar studies in the 1960s1 indicated that the rainrates of tropical clouds peak out BEFORE the cloud tops reached much below freezing, a finding that has been confirmed in some aircraft studies of rainrates in tropical clouds2. Icy tops going to 30 thousand or more really didn’t do much but add fluff. All that really heavy rain that developed before the cloud tops reached the freezing level was just due to collisions with coalescence (AKA here, but nowhere else because its too silly, as “coalision.”) So, “coalision” can be an extremely powerful and efficient way to get the water out of clouds and onto the ground!
Scattered storms beautified the sky the whole day in the area. More are expected today, as you likely know. Have camera ready! Hope you get shafted!
Cool snap, maybe with rain, virtually guaranteed now for about the 26th-27th. Should make a good dent in the fly season, if you got horses and have been battling them all summer you’ll really welcome this.
Your Cloud Diary for September 19, 2014.
We start with an early morning vignette, down there somewhere:
6:32 AM. Overcast Stratocumulus (likely with bulging tops) and the distant top of a Cumulonimbus, that bright sliver, lower right. 6:33 AM. Cumulonimbus top NW of Catalina, an usual sight since it had arisen from such low based clouds in the “boundary layer”. Usually this only happens due to heating by the sun later in the morning or in the afternoon, of course.
Vignette: When this cloud bank above Sutherland Heights (shown above) darkened up, looked more organized, and with Cumulonimbus tops visible and showers already nearby, I made the not-so-surprising comment to two hikers about to leave on their hike hour long hike, “Watch out for these clouds overhead!”
They got shafted, see photo below; came back soaked, their dogs, too.
But, I had done my best. True, it was early morning, and after all, those hikers were likely thinking, “it doesn’t rain much here in Catalina in the early morning” (unless its FOUR inches like two weeks ago).
7:30 AM. Heavy rain falls S of Sutherland Heights, on hikers who had been warned about a dump; produced a warm feeling.
8:14 AM. Those showers moved off into the Catalina Mountains and the early morning sun provided a spectacular scene. (From the “Not-Taken While-Driving” Collection, though certain attributes here suggest that someone just pointed a camera in any old way and got this shot. Pretty clever to make it look that way, kind of adds an “action: attribute to the shot.
Cloud of the Day:
1:47 PM. I meet a friend, southbound, on Equestrian Trail. I advise her that if she drives under this cloud, she will get dumped on. She continues on. There is no outward sign of ice, and no shaft, however.
1:49 PM. Thunder begins to grumble repeatedly from this cloud only two minutes later! The conversion from a droplet top to an ice (glaciated) one is clearly in progress. My friend has disappeared over the horizon, which isn’t that far in only two minutes.
1:58 PM. Kaboom! I was actually a little late getting the fallout to the ground. Will have to look at the video to see the shaft plummet down. Produced a nice little haboobula, too, on the left side, where the shaft is densest. I wondered if my friend had gotten “shafted”, as we say here when folks are under the rain shaft.
2:57 PM. An isolated Cu congestus thrusts three turrets out. Who will it turn out to be?2:53 PM. Stable layer halts growth of the two outer turrets and they begin to flatten, but caulifower top in the middle shows that further growth will occur. Will those wings develop ice? Beginning to look like a rocking horse, I see…Look! Its Snoopy with wings! (Ice seen on the right, also on the left, but less obvious).4:31 PM. Pile of Cumulus congestus clouds weighs down the Catalina Mountains again as they did the previous evening. Had to pull off the road this time, jump out car to get this grand scene, well, to me anyway. Hungry passengers a little annoyed at the pre-dinner delay. You know, had to complain a little.6:18 PM. Another sunset reason why we live here and love it so much.6:20 PM. Late storms continue on The Rim, toward Globe
The End, enjoy our last couple days, it would seem, of our summer thunderstorm season. Oh, me.
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1Saunders, R. M., 1965; J. Atmos. Sci.
2Cloud Maven Person with Hobbs, 2005, Quart; J. Roy. Met, Soc.
