About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
One branch of a seemingly bifurcated plume, spread north along the side of Samaniego Ridge. The other branch appeared to moved out of Tucson to Continental Ranch, “thence” northward toward the east side of the Tortolita Mountains. It’s happened before, but is pretty rare, maybe once a year occurrence.
(Took an hour for these first three jpegs to be uploaded to WP, btw.)
Quitting here due to slower than dial-up service, hosting service, “godaddy” has confirmed its not them….
a
Rain almost certain today and/or tonight in Sutherland Heights.
See for yourself:
Our persistent easterly flow is dragging smoke that circulated from the Pac NW and MT fires into AZ since that smoke was circulated southward into the southern Plains States as we saw in those back trajectories from a couple of days ago.
Some Cumulonimbus clouds are foretold to develop in the region today, more tomorrow. This should mean some clarification of the air as the smoky air is mixed over a great depth. Also it appears that the air will be coming from a less smoky direction, more from the south in two or three days, along with a much greater chance for significant rain, and that should help get Arizona skies back to the ones we love!
The End
August rainfall total in Sutherland Heights: A measly 1.10 inches, to editorialize that bit, rather than to just report facts. Average August rain here is 3.16 inches. Egad.
End of looking back….”What’s the Use” (Tuxedomoon) said it best, well, maybe.
What about the haze? Where’s it coming from and its awful! And its here again today. Reminds one who lived in southern California of summer skies in southern California, hazy, whitish, the orange- colored sunsets that people sometimes thought were “so pretty” but they were ugly because they were orange because of smoke and smog and s like that.
Where’s it coming from, to repeat? Not sure. But see back trajectories below.
These suggest its coming from the east in the last day or so of the trajectories. The trajectories start high up because we’re in the descending air branch of an upper air anti-cyclone that’s dessicating the air, preventing even little baby Cumulus from forming.
————-
Lidia’s moisture will help some, but it appears no rain will reach us today, Dang.
But things get more promising for at least a short return of the summer rain season (remember, the real monsoon is in India) in the immediate days ahead, phrasingly vague enough to insure a great forecast verfication! haha
Looks across Catalina and Oro Valley toward the Twin Peaks area yesterday afternoon. “Egad”, to repeat a mild expletive.
Every once in a great while, we have days where fairly thick clouds do not produce even a sprinkle, even though their tops are a little below freezing, but not quite cold enough for natural ice to form. Yesterday was one of those days.
And it was a day you, a cloud maven junior member, could likely have done something about it: rented a small plane or helicopter capable of flying up to around 15,000 kft ASL, taking a bag of commercially available dry ice pellets, then drop them into the fattest, highest Cumulus tops you saw while nipping them in VFR flight mode, and, “violet!”, ice would have formed along the path of the falling dry ice pellets!
So what were the ingredients that made yesterday so special for a little renegade cloud seeding?
The clouds that did not rain were pretty thick for ones that didn’t rain naturally, maybe 5,000 to 6,000 thousand feet thick in their maximum “overshooting” tops, and temperatures at top were a little below freezing, but warmer than -10° C. At lower top temperatures ice would likely have formed naturally. Here’s the annotated TUS sounding from yesterday afternoon from IPS MeteoStar:
Here’s how it works: the dry ice pellets, themselves at -72° C, will chill the air it comes in contact with to -40° C, resulting in the formation of jillions of tiny ice crystals in each pellet’s wake, which are then spread over a wider region in the following minutes due to turbulence in the cloud. In essence, each pellet is creating a tiny, vertical “contrail” in that cloud, as least in those upper parts of the cloud below freezing. (Bases yesterday were a little above freezing, around 2° C, while the highest afternoon tops locally appeared to run between -5° and -10° in clouds that were forming in more haze and smoke than usual (wonder if you noticed that?) Haze and smoke tend to reduce droplet sizes, and in doing that, make it harder to form ice and rain, especially in marginal clouds for that, such as we had yesterday.
What happens next is that the “supercooled” water in the cloud evaporates around those crystals due to the dry ice bombardment, while the crystals take up that evaporated vapor. When the crystals get large enough, they may collide with some remaining cloud droplets, if there are any around. Usually all those crystals that have formed will not left too many droplets in their vicinity.
As the crystals grow in size, and because they are in such high concentrations, they will bump into one another and form clusters of ice crystals we call snowflakes. Cloud Maven Person has, along with Professor Doctor Lawrence F. Radke, the latter the “Flight Scientist” in those days with the University of Washington Huskies’ Cloud Physics Group1 in the late 1970s, made snowflakes the size of pie plates (fluffy light ones without a lot of water content) in Cumulus clouds like yesterday’s here.
IMO you would have created not something of much importance, but rather just an annoying sprinkle or very light shower for those out hiking, horseying around on their horses, biking the trails, on an otherwise perfect day for outdoor activities.
One of the problems, long known about in such seeding experiments as could have taken place yesterday, is that the cloudy air is moving THROUGH the cloud, exiting at the downwind location. That is, lower clouds in particular, move SLOWER than the air itself2.
So, you drop some dry ice in a nice turret, the air you dropped it is, along with that turret’s air, will be moving downwind and is going to go out into clear air eventually. So, if the crystals don’t stay in a turret and upward moving air, but goes out the side of the cloud or into “shelf clouds” like yesterday, those crystals/snowflakes aren’t going to grow much, and will remain “light and fluffy” even though they could be huge because they are like “powder snow” not a lot of water mass in them. When they melted at cloud base, they might end up being just drizzle-sized drop (less than 500 microns across) or very small raindrops. So, that’s why you would likely have gotten just a sprinkle or very light rain shower had you done some unlawful, renegade cloud seeding yesterday. Remember, just like when you hike in the State Land Trust areas, you need a permit to seed legally.
This message brought to you as a public service by CMP.
While warm weather returns to AZ over the next week to12 days or so, there is now, and this goes with climo, a big trough that barges into all of the West Coast in two weeks.
When I say climo, I mean that there is a noticeable tendency for this to happen in mid-November in the longterm upper air records so that in some areas of California, for example, there is a modest increase in the chance of rain in mid-month over other times in the month. These kinds of things in weather are termed, “singularities” like the supposed, “January thaw” back East. This mid-November annual trough passage may be related to the increasing speed of the jet stream in the Pacific as winter approaches, something that changes the spacing between the troughs. Pure speculation.
But in any event, be on the lookout for a major change in weather here between the 17th and 20th of November. Something like this is starting to show up in the models.
The End
———
1Later renamed the Cloud and Aerosol Research Group.
2Something that was even noticed in small tradewind Cumulus in the Pacific in the 1950s by Joanne Malkus (later, Joanne Simpson) and her colleagues.
Through deliberate deception, the title is likely to bring in quite a few football-centric people, since “jumbo package” is a term used when an offensive team bring in all the “Sumo wrestlers” they have, usually in attempts to score a touchdown from 6 inches outside the goal line.
The “jumbo package”, however, is about some weather, essentially at “mid-field” rather than on the goal line (i.e., just ahead):
A large and very strong upper low center is forecast to arrive on Sunday, October 25th, football day, the last reference to football in this blog. As it passes over Arizona, the first snow of the year would likely fall on the ‘Frisco Peaks by Flagstaff.
Tremendous rains, too, would occur here in AZ with this low, espepcially2 here the SE corner, should it happen. See WRF-GFS model outputs below, as rendered by IPS MeteoStar:
But does it happen?
Let’s check the spaghetti from NOAA for a hint about whether this weather happenstance has much chance of occurring:
You, too, as an expert on spaghetti now, are as crestfallen as I was to see this spag output from last night, showing that the espepcially strong low is, in fact, an outlier; a not impossible situation, but an unlikely one since we don’t have the bunched blue contours where the jet stream is strong, down thisaway. Rather, those blue lines are grouped over the Pac NW, and only one or two bluish contours are down here, ones that would be associated with that upper low on the 500 mb map above for Oct. 25th
Still, even when you know its an outlier, it brings hope for a bountiful rain, which is good. Will monitor this as the days go by, in case the outlier spaghetti output is an outlier.
Of course, as all weatherman know, we still have our boomerang friend Joe Low returning with rain; that’s in the bag, and has a little “friend” following behind him. These, combined, should bring substantial rains overall in AZ and in the Catalina area, in the form of scattered showers and TSTMs that persist over several days beginning later Thursday through Monday. Joe et al. are slowpokes, which is good.
Haze and smoke are up, if you’ve noticed that our skies have been not so blue, but whitish. Stuff is coming up from Mexico it appears; (Smoky) Joe will bring more of that before it gets here. So, look for a hazy patches of Altocu and/or Cirrus in the next couple of days. Maybe a small Cu off in the distance.
The End
——————————-
2“Espepcially” is a word I made up via some inadvertent key strokes, but I kind of like it: “In particular, but with some energy.” BTW, Coke tastes better than Pepsi, if that new, unexpected word made you think of a soft drink.
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.
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!
—————————————————-
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.
Well, that cloud WAS “creeping” toward us after suddenly appearing on Pusch Ridge at dawn… Looky here:
———–
With Halloween only 10 and half months away, I thought I would “get in the mood” and make up a little creepy-ness for the little kids who read this blog. Hi, kids! Hope you didn’t get too scared reading this. “Uncle Artie” is sorry if you did get scared.
What you saw in that sequence of Stratus fractus movement is also demonstrative of what often happens to smog layers funneling out of the Tucson area toward Mark Albright’s house in Continental Ranch, Marana. Here’s an example of creepy morning smog (smoke and other aerosol junk), partitioned to the lowest layers near the ground by a radiation inversion, a temperature reversal that develops at night that results in a temperature rise as you go up. In the afternoons, after the sun has done its work for awhile, the temperature DECLINES as you go up and the smog molecules are dispersed over greater and greater depths. Got it?
Now, where was I after that big caption….?
Sunday marathoners, achtung!
Looking more like a dry day now on Marathon Day, Sunday, though a cold front will have gone by just before it starts. Looks like measurable precip will be partitioned to the north of Oracle on Sunday, but it will likely be cloudy with Stratocumulus clouds as the day starts, but those should gradually disperse into scattered to broken Cumulus clouds with virga by mid-day, some of those deeper Cu could produce a cold one; i. e., a sprinkle.
Jet core (at 500 mb, 18,000 feet or so) is well north of TUS as Sunday starts, and its really hard to get precip here until the core passes, which on Sunday will be later in the day. But then, the cold front has long gone, and the tendency for precip with the jet core has diminished (subsiding air behind the front is moving in then) to just scattered deeper Cumulus clouds having some ice-forming potential. Deeper clouds are stymied on the right side of the jet (looking downwind) overall in the Southwest in the wintertime by warmer air aloft and stable layers, the kind that produce lenticular clouds.
Below, what”m trying to say in words, is shown in this 500 mb forecast from IPS Meteostar with the wind velocities on it:
Since this is an analysis from a model output, one inherently containing error, there is that inherent bit of uncertainty. So, you, as a weatherfolkperson, imagine what can go the best (the most rainful error), and the worst, and make outlier predictions. Potential rain here in Catalina on Sunday: max, a tenth (everything goes right); bottom, zero (or trace), in this case, as predicted by this model.
I will leave you with this. I think its looking more promising for storms later in the month. I think you’ll see what I mean:
The End
PS: Lots of low temperature records falling in the West these days.
I wonder if you noticed the blackish smog layer to the south and southwest of Catalina yesterday? Usually it stays down that way, flowing peacefully toward the northwest from Tucson across Marana and Avra Valley, an area where a close meteorologist friend and his wife just bought a house even though they knew this happens in winter and not one in Catalina where we normally escape this characteristic Tucson smog plume. They must like winter smog overhead, but then as the sun heats the ground, it comes down to you. Go figure.
Here is yesterday’s Tucson smog plume exiting Tucson:
But then, in the later morning hours, a southerly wind brought that smog bank to our normally clear air oasis of Catalina, infecting the shallow Cu fractus clouds that formed as the sun heated the ground. This was a real disappointment since probably most of us were expecting the kind of pristine view of the Catalinas yesterday morning.
Fortunately the smog was dispersed as the day wore on. As the layer in which it is contained gets deeper, and without more smog being added to it, the amount of smog, say, per cubic mile diminishes and pretty soon it gets so thin you can’t detect it with your eyes. Still, exactly the same amount might be in the column of air between you and the higher cloud bottoms. Here’s what it looked like in the later afternoon:
BTW, while its easy to see that the Cumulus fractus clouds in the second photo are very low, in the 3rd photo above it’s much harder to detect how high these small Cumulus are. The TUS sounding indicated that they topped out at 9,000 feet, or only about the same height as Ms. Mt. Lemmon! Top temperatures in these smoke-filled clouds were no colder than about -8 C (about 20 F), too warm for ice to form in them, especially when the cloud droplets are reduced in size by smog. The larger the cloud droplets, the higher the temperature at which ice begins to form in them, and so smog generally reduces the chance of rain in shallower clouds.
This is why oceanic clouds in pristine regions lacking smog, even shallow ones, rain or drizzle so easily. The cloud droplets are much larger in those clouds right from the get go than those in smoggy regions. So oceanic clouds can rain either because those larger cloud drops reach sizes where they can collide and stick together, forming larger drops that can fall out (“warm rain process”) or form ice at the highest temperatures known for ice formation, -4 to -5 C (23-25 F). Usually both processes are work in those ocean clouds that rain so efficiently. They’re pretty great, really, such little clouds that rain.
Vacation in Hawaii if you’d like to see some up close (though not downwind of the Kilauea volcano plume and in the lee of the Big Island of Hawaii since that volcanic plume can smoke up the clouds real bad there and they stop being so darn efficient as rain producers. Recall that the biggest drop in the world was measured in clouds in Hawaii (1 cm in diameter, Beard, private communication, received AFTER Peter Hobbs and me got the Guinness record for the biggest drop ever measured, 8.6 mm in diameter–got a lotta publicity around the world, too, calls came from everywhere!).
You see, Beard didn’t publish anything about HIS BIG DROP; we published ours in a refereed journal. “Neeny, neeny, neeny”, I think is what you conclude here. Immaturity: sometimes I think its not valued enough in life.
That’s what its like in academia; you publish or die! Die that slow death as an “Assistant Associate” professor of something, never reaching the exalted “Professor” status.
We had two forms of ice yesterday morning that you may have noticed, say, on your car if it was parked outside overnight. There were originally rain drops left from the storm that froze in place during the cold night (was 30 F here yesterday morning), and then the deposited ice from water vapor on top of the drops.
The deposition process, as we call it, leads to hoar frost ice crystals growing in time as the molecules of water vapor add to it during the night. This combo ice led to an unusual site on the car before the sun did away with it. Here are a couple of shots of this unusual sight:
After the “sunny malaise” for 5-6 days, with Arizonans statewide out doing things, its back to the Bowl, the trough bowl. The period we’re in now might be called, “a sucker ridge”, a high pressure ridge that is. You might well think, “Well, that’s it for winter in Arizona!” after a few days of the “sunny malaise”, but you’d be WRONG. I can’t emphasize the word, “wrong” enough. The Bowl comes back with a vengeance, too, when it reforms here in the Southwest; there will be one storm and cold blast after another. If you’re a snowbird, you might start to cry, and wonder why you didn’t go to Costa Rica for the winter.
Well, I am looking forward to storms and seeing more scenes of white mountains deep in snow, and green vegetation shooting skyward. That’s the promise of the “Bowl” ahead, where storms collect, in the weeks ahead right into March.
Taking a few days off now, likely without pay, to replenish mind, get out and do things like the rest of Arizonans will. Will give you time to ruminate on all that’s been said here over the past year or so, correct and incorrect, mature and immature…
The End.
