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.
Wednesdays here in Catalinaland are, of course, trash and recycling days. And, along with T and R day, we found ourselves amidst some pretty pretty scenes, and in some cases, extraordinary ones,….and a little rain (a trace here in The Heights). I reprise those scenes in case you missed them; you probably did because you’re not some kind of photonut like the writer.
However, be advised that some of the mid-day photos will show smog, smog that was ingested into our poor clouds.
That smog bank, emitted from the Tucson area, almost reached Catalina yesterday during the day. It came up around Pusch Ridge and up along the west side of Samaniego Ridge and almost reached Catalina before its advance was halted by a north wind push and it retreated to the the south. My heart was beating so fast that it might overrun us! Marana and Oro Valley were heavily contaminated for awhile. And smog is like a cloud cancer1.
7:46 AM. A rare display of Stratus along the Tortolita Mountains. If you were hiking and were in this, it would be fog to you, still Stratus to me viewing it.7:46 AM. Rare shot of what appears to be ground fog or just fog rolling eastward out of Tucson. Some flakes of Altocumulus above, and a higher layer of Stratus on the Tucson Mountains.
8:49 AM. This was an amazing sight, to see a thin Stratus cloud fronting an early morning Cumulonimbus capillatus. The Stratus is hard to see, but its the thin dark line on the horizon above Priscilla’s house below the turrets and ice of the Cb. The only other time I have seen such a sight was in Seattle after a snow with Stratus clouds and fog all around the city, but with warm Puget Sound sending up plumes of big Cumulus clouds.
10:37 AM. The day was not without some cloud levity, as these “twin tower” Cumulus clouds show, drawing attention to themselves.
11:26 AM. First ice in clouds becomes visible. It was obvious a few minutes later, but if you saw at this time, or can find it here, you are a pretty CMJ, worthy of an accolade. Of course, if you looked at a radar map of the area, you would have known where to look in advance since there was a small echo in this complex by this time. The precip just was not enough to form a shaft. Note, as well, that Twin Peaks, Continental Ranch area is NOT visible due to the smog bank that was going to move up this way, as it turned out. And look how gorgeous it is toward the Tortolita Mountains!
11:38 AM. OK, here the ice from that turret in the prior photo is now obvious (center frizzy area). However, it was also obvious that the smog toward Marana/Continental Ranch was now closer, even while we had a north wind here in Catalina. Was that southwest wind going to win and mess up our fantastic skies?11:42 AM. Here you can see the smog as it was advancing around Push Ridge and had gotten farther north along the side of Samaniego Ridge. Those lower cloud fragments along Pusch Ridge at the top of the smog tell you that the air was more moist than the air our Cumulus clouds were forming in, and therefore, that this advancing smog bank likely associated with deliquesced aerosols from cars and other urban effluents (aka, “air sewage”) accumulated during the Tucson fog earlier that morning that was now being mixed into a deeper layer and heading this way! To think of breathing air like that. in a short while..it was a ghastly thought.
12:12 PM. To make a short story long, the advance of the smog, with its lower based clouds got as far as Golder Ranch Drive over there by Samaniego Ridge (whitish area below the lowest cloud base on the left), before receding under a freshet of north wind. However, some southern parts of Catalina were affected for a short time.
1:14 PM. By this time, larger complexes of Cumulonimbus clouds, pretty weak ones, were developing over and north of the Tortolita Mountains and upstream of us offering the hope of some measurable rain in Catalina, the smog pretty much pushed back to the southern parts or Oro Valley and Marana.
2:00 PM. Widespread light rain showers were in progress from these weak Cumulonimbus clouds, but sadly, bypassing Catalina. But huge visual payoffs were ahead as the clouds broke at times, and some stunning sights emerged.
2:35 PM. Stunning….to me, anyway. View this in full screen mode for best impact. Later, more accessible stunning.
3:01 PM. Breathtaking; in total awe of this scene! Note gliaciated tower at right.
4:28 PM. And those scenes just kept coming! It was hard to be indoors for even a minute.
5:28 PM. The fading sunlight and the fading Cu only got more breathtaking. And we realize how lucky we are to be here and see scenes like this so often.
5:38 PM. The smog belt, held at bay during the day, still lurked to the SW of us, compromising our sunset by providing a reddish-yellowish sickening hue to it, a sign of a smoky presence, that may compromise today if we’re unlucky.
The weather ahead and way ahead
Well, RIP El Niño, an EN expert has written me just yesterday. Not much left of it he says, having a attached a map of ocean temperature anomalies to kind of rub it in. So we can’t count on hot water in the eastern Pacific to help fuel Southwest storms as was expected by the CPC and others last spring. But, that doesn’t mean that there can’t be a juicy late winter and spring, but the odds are down.
And, we won’t see clouds like yesterday until the long-foretold-by- spaghetti trough arrives around the 22nd of January, and with it some chance of rain. Doesn’t look like it could possibly be very much. BTW, Only 0.02 inches total in three days of light showers in the current situation. :{
BUT…..in the longer term, spaghetti is once again HINTING at a break-on-through-to-the-other side situation, your writer’s favorite as a kid, 10-14 days from now. A high builds up along the West Coast and in the eastern Pacific, gets too big for its britches, can’t maintain its giant north-south range, drifts farther and farther north and begins to break up, kind of looking like a horseshoe with the open end down (toward the south) as the jet stream “breaks on through to the other side” and “underneath”, that being a jet stream comes through from the warm subtropical central Pacific to the southern areas of the West Coast.
The north part of the West Coast and Gulf of Alaska are dominated by higher pressure with lower pressure to the south, so its kind of an upside-down-from-normal looking weather map, pretty rare, and that’s why its cherished by yours truly.
The End, at last!
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1As you know, when clouds are heavily contaminated with air pollution, they can’t rain as easily because the droplets are smaller inhibiting rain in two ways: by preventing the formation of drizzle and rain drops, and making it more difficult for ice to form since the formation of ice happens at higher temperatures when cloud droplets are larger. So, clouds have to be taller when they are polluted to produce rain, either way.
An unusual sight yesterday: bulging dawn Cumulus fronted by fog. These Cumulus (not spawned by ground currents) suggest instability aloft, a rapid decline in temperatures with increasing height, which allows the buoyancy of “warmish air” in-cloud surrounded by cooler air to go up, whilst fog1 suggests the opposite; cold, damp, heavy air that can’t go anywhere but down, slip sliding away as it did yesterday because its topped by warmer air, a atmospheric “glass ceiling”. Ground fog like this is colder air that you can see.
7:21 AM. Looking NW from Equestrian Trail Road across Oro Valley. 7:19 AM. Odd multiple layers of ground fog (lowest) and Stratus clouds (“clouds” because they’re not on the ground) with shreds of Cumulus fractus above Samaniego Ridge. 7:07 AM. As above, suggesting a very fine layering of moist air with little temperature caps.
Here in Catalinaland, this kind of layering of cold air, as most of you know, is endemic on clear nights. Those who drive down across the CDO wash from Sutherland Heights or along Lago del Oro from the surrounding higher terrain know. Because of the stupefying amounts of rain in the past three days, the air is damp enough at ground level to form fog and you can see whose colder at night than you are IF you are above it. Also, anyone who walks their dog in the morning passed innocuous looking gullies, is aware of how cold air flows downhill and collects in low places.
The lack of density of this fog indicated that it formed in real clean air, air that didn’t have a lot of junk in it (which would also contain a lot of CCN, cloud condensation nuclei. Pretty hard to get fogs like we had in Bakersfield, CA.
Once things warmed up some, and with Arctic like air up top, Cumulus arose, a couple of which sprouted icy tops and shafts, namely, became small Cumulonimbus clouds, tops around 20-25 kft. Along with these clouds, there was a treasure of sunny highlights and shadows moving across the Catalinas. Here you go:
10:49 AM. Small Cumulus humilis, mediocris begin forming as temperature “warms up” to 50 F (egad).
11:13 AM. There’s water (glinting) on them rocks! One of the prettiest sights we get to see on the Catalinas after some rain. Not enough water was dumped on the mountains during our drought-denting storm to get water into the CDO Wash locally, but the Sutherland Wash developed a trickle. Just too much dry ground up there for much runoff with the relatively steady rains that we had.
12:10 PM. Small Cumulonimbus clouds erupt just north of Saddlebrooke. Thought I heard thunder from this complex later. 2:50 PM. While small Cbs developed to the north, the Cat Mountains were only able to produce Cumulus congestus (“heavy Cu”). Didn’t see any ice; neither did you, or there’s something wrong. But, if you go here (U of AZ time lapse), you WILL see some forming in the downstream portions of clouds over the Catalinas. Sometimes not seeing ice is because the tops are blowing off away from you before they show it, especially when there isn’t a lot.3:48 PM. Last gasp Cu congestus. Will highest turret form ice?3:49 PM. Ice starting to show!3:53 PM. Droplet cloud completely gone. No question now, nice ice plume. You want to target aircraft into densest portions of this ghostly veil of ice; will correlate with densest portions of liquid cloud. Not enough ice for a shaft below the cloud, but someone felt a few drops below it!
Below, one of the attributes of our partly cloudy days and low near-winter sun angle; pretty lighting:
5:19 PM.5:06 PM.3:54 PM.
The weather way ahead, first week in December.
Pile of cold air to drive into West Coast and Rockies during the first week in December. Snow even possible here, the air is that cold, but mainly the cold air will likely lead to the first cold spell where temps drop significantly below freezing. The worst days look like the 5th and 6th right now, after the threat of rain and or snow pass. So, if you have an evap cooler, you’ll definitely want to have it drained before then if you haven’t already taken care of it (like me).
Rain threat at the end of the month/first day or so in December is fading some in mods, but I refuse to give up on it!
The End.
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1Fog is “gof” spelled backwards, BTW. Has a lot of meanings and I avoided the obvious juvenile approach (today), “Think I’ll go goffing today” which I wouldn’t say anyway because I don’t play gof.