6:52 AM. Altocumulus cloudlets over and east of the Catalinas.6:52 AM. Sprinting to the other side of the house, this spectacular scene of virga falling from Altostratus. Breathtaking!6:53 AM. To the NW, the virga roiled downward into mammatus bulges under lit by the sun.6:54 AM. The color was fading just in a minute or two, but it was still a breathtaking panorama I thought you should see.
Some additional commentary about these scenes. One of the remarkable things about clouds, a real unknown, is how clouds such as Altocumulus (1st photo) can get so cold, colder than it was this mid-November in Wyoming, and can remain all or mostly water drops, which is what you are looking at in those cloudlets over and beyond the Catalinas. Pretty amazing. This phenomenon has been known about for decades, but not fully explained. We expect to see a lot of ice in clouds with tops colder than -30 C (-22 F) as you might imagine.
Here’s the sounding near the time of these photos, with writing on it:
———-Begin learning module———————————-
The Tucson balloon sounding, launched around 3:30 AM AST yesterday morning.
As a CMJ, you need to be armed with explanations if, on a morning walk, your neighbor, at first overwhelmed by the morning beauty, but then instead of being quiet, goes on to ask, “Hey, aren’t those clouds composed of droplets; they must be pretty low and warm?”
Since you’ve already seen the TUS sounding for the hours just before this, you know those cloud bottoms are real cold and high, -26 C, and 19,000 feet above you here in Catalina, and tops are really cold, about -32 C (-26 F), you cringe. What to say? How do you explain clouds that can sit there at -32 C and develop little or no ice, while knowing that Cumulus clouds, ones whose tops have never been colder than -7 C, can be completely composed of ice just after reaching up to that temperature?
—————-End of learning module, such as it was———————
Here’s another example from yesterday of extremely cold clouds with few ice crystals:
9:36 AM. Altocumulus perlucidus opacus (sun’s position is not detectable). The TUS sounding for the morning would not be valid at this time since the cloud bases were slowly lowering but they would still be about -20 C at this time, height about 17,000 feet above ground level. And, at this temperature, such clouds are ultraripe for ice production by aircraft that may flay threw them. See next photo for a POSSIBLE aircraft production of ice in these cold clouds.
10:43 AM. Of course, all of you were looking for some aircraft perturbation I’m sure, and this seemed “too linear, too uniform, the crystals too small (as deduced by the sloping lines of virga underneath this line for the ice to be natural. No other virga looked like this having straight fine lines underneath, the thing typical of contrails. However, its not the typical ice canal, either, with clearings beginning on the sides. In fact, the cloud seems thicker here where an aircraft may have traversed it, posing an explanatory challenge. Also counter to reason, why would an aircraft fly so far in what would have been light rime icing conditions in those Altocumulus clouds? Lots of questions, no really good answers.
11:07 AM. Linear feature passes over Catalinaland. Was hoping for a drop so I could claim it had rained in November, even if it had been a phony rain.
11:32 AM. Looks phony to me! Not a real cloud. I think we’re looking now at the tube of high concentrations tiny ice crystals that slowly settled out from that Altocumulus layer after an aircraft went through it–this tube to me appears to be BELOW the general layer, due to settling out after a few larger ice crystals fell out first. Am about 60 % sure that’s what happened and caused that linear feature. Getting pretty worked up about, too.
Well, Shakespeare said it: “Much ado about nothing,” so it must be important if he said it.
Had some really nice cloud scenes after the big clearing came through in mid-afternoon:
3:38 PM. Our typical spectacular lighting on the Catalinas scenes as storms move away.
4:49 PM. A dramatic finish to the day; light showers hit south and southwest of Tucson, but faded before arriving here.
There were some light showers that produced as much as 0.20 inches of rain in the south and east parts of Tucson late yesterday afternoon and evening. Nice for them.
The weather way ahead
Nothing in the way of rain in the immediate future. Have to wait until December for any real chances. See this bad boy for December 6-7th, this panel only 360 h from now1!
Valid at 11 PM AST December 6th. Note that the heaviest rain in Arizona is over Catalina! These are totals that accumulated in the 12 h prior to 11 PM AST. Hope I made you that bit happier showing you this. It’s a pretty cold system, too, might be a close call for snow here.
The End.
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1360 h in advance, even using our best model, is about in time like the distance to Betelgeuse in light years. Hence, caution when the writer says, “only.”
Started out clear yesterday. Below, an example of that completely clear sky in case you missed it.
10:06 AM. Clear skies are evident as we look in the general direction of Baja California. HOWEVER, note shallow smog plume exiting Tucson and flows northwestward across Continental Ranch over there by Twin Peaks where fellow University of Washington meteorologist, Mark Albright, lives.
I think it is interesting that Mark would chose to live as a snowbird in a smog plume rather than here in Catalina where that Tucson smog plume rarely strikes. Its pretty regular down there because the normal morning wind in Tucson is from the southeast and that wind shoves the urban smog over to Mark’s house on many cold mornings. Pretty funny, really.
Yesterday’s clouds
In the mid-afternoon, a stream of patchy Cirrus was beginning to creep over us. If you don’t believe me, you can see it in the University of Arizona time lapse film for yesterday.
And, in those leading Cirrus clouds were some spectacular, stupefying really, complex patterns of cloud formation and and holes in them, ones like CM had never seen before except maybe that one time in Durango back in the 1970s. Here are some examples of those odd that were up there:
3:14 PM overview of Cirrocumulus and Cirrus clouds with oddities.3:14 PM Close up of previous cloud scene. Note all the weird stuff going on.3:22 PM. More oddities. Going crazy trying to understand what the HECK is going on!3:23 PM. Close up of rectangular “fringe.”
Started to breath a sigh of relief when this melange of complexity moved off rapidly worrying that someone might call and ask me to explain it. So, when some Cirrus uncinus and/or the rarely seen Cirrus castellanus came by I started to relax, feel confident again. Here are some of those pretty shots of little, icy clouds trailing light snow showers, likely, to repeat again, crystals called bullet rosettes. The ones in the part of the cloud from which they spew are likely tiny prisms, side planes, and tiny solid columns, thick, but tiny hexagonal plates with little fall speed, so those hang up there, while the favored ones in the best tiny updrafts in these clouds that resemble tiny glacial Cumulus clouds grow from those kind germ crystals into bullet rosettes, complicated crystals with multiple tiny columns sticking out of them. If you would like to read all about the crystals that form in high icy clouds like these you should spend some time browsing this paper, co-authored by the great John Hallett1 I really like footnotes–yes, of the Hallett and Mossop riming and splintering mechanism, discovered by them in 1974. Helped explain why there was a LOT of extra ice in clouds that shouldn’t have it.
Here’s one more weird scene in Cirrus before moving on to something explicable:
3:43 PM. Holes, plops of downward moving air amid the Cirrus/Cirrocumulus. But why so round?
Thankfully, here’s what transpired next at Cirrus levels:
4:02 PM. Cirrus uncinus (one with tufts or hooks at the top and long streamers of ice below them) followed the strangely patterned sky.4:03 PM. Look at all the larger ice crystals pouring out these little guys! Its amazing. Notice how FINE those strands are. Airborne work we did indicated that the cores were only a 5-20 meters wide!4:20 PM. Reminded me of a ballet the way the clouds and the streamers were arranged around one another.4:17 PM. Just a little before the dancing clouds came by, there toward the Gap was this CIrrus castellanus mimicry of a full grown Cumulonimbus capillatus (tuft in center of photo). Look, it even has a tiny anvil spreading out, to use the word “tiny” for the 18th time! How fun was that to see!
Of course, with all the patchy Cirrus around we were guaranteed a nice sunset and it did not disappoint:
5:29 PM. Sunset.
Today’s clouds
Heavy ice clouds, several kilometers thick at times. We call that kind of fray, often full sky-covering layer, Altostratus. Likely some Altocu around, too. Will look now and see if I see any of those latter ones. Oops, too dark.
With clouds kilometers thick, tops at Cirrus levels, you can expect to see virga, and the chance of a few “sprinkles-its-not-drizzle” later in the day. The whole progression of clouds can be seen from the U of AZ model output from last night in these forecast soundings for Tucson. As per usual, the bottoms get lower and lower as the day goes by, but are still up around 13, 000 feet above Catalina by around sunset. So, will be tough to get a drop to the ground before then. U of AZ mod thinks all measurable rain will be to the south of us. Oh, me.
BTW, and this is an embarrassment, it was asserted by this keyboard that rain would fall in November at the outset of the month. This is the last chance for that! Egad. But forgetting that possible gaffe, moving ahead anyway to what’s going to happen in December (of this year).
The storms way ahead, that is, ones in early December.
Those early December storms for us are coming and going in the WRF-GFS runs. But I am counting on rain here in early December myself due to an interpretation of those weird in so many ways, “spaghetti plots.” I think they’re showing, and continue to do so, significant troughs coming through the Southwest in early December.
The End
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1Later after the referenced paper above, and this is quite interesting, the great Hallett was to claim that me and Pete Hobbs had embarrassed2 the entire field of airborne researchers due to a paper published by us way back in 1983 (J. Hallett, 2008, communicated by him during his presentation at the Pete Hobbs Symposium Day of the American Meteorological Society, New Orleans.
2But it was a good embarrassment, not a bad one due to incompetence, I think.
6:55 AM. A surnrise glow from receding CIrrus spissatus highlights Samaniego Ridge. Very pretty and dramatic.
8:19 AM. Forming uncinus, CIrrus that is. Note trails of precip beginnng to form under these tufts of Cirrus castellanus clouds.9:06 AM. Jet contrails begin to show up in a Cirrocumulus cloud composed of supercooled cloud droplets. You know what going to happen….something special for you to log in your cloud diary.
9:20 AM. Another patch of supercooled, very supercooled for that matter, Cirrocumulus with evidence of a jet contrail. But, is the jet above or IN the Cirrocu? TIme will tell.
How cold were those Cc clouds? See below.
(Begin technical module)
The Tucson balloon sounding1 for 5 AM AST, November 19th with writing on it. The height of these clouds was slightly lower in the mid-afternoon, but (as Altomumulus then) were still about -23 C. As we know, cloud bottoms almost always get lower with passing time because the higher parts of cloud shields are moving faster.
In the mid- -20s C, around -15 F. Height, about 21,000 feet above the ground here in Catalina. Hope you got that estimate of cloud height right.
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Continuing…
9:21 AM. ANOTHER jet streaks by! This is going to be darn interesting, a rarity, like seeing a grey parrot in Catalina! The secret about what height the first jet was flying at is beginning to be revealed. Can you see what’s happening to that first contrail a little below the new one? This is a great test to see how far you’ve come as a CMJ (cloud maven junior)!
Here’s what happened in the Cirrocumulus cloud layer in yesterday’s special day, a pretty rare one, after the jets flew through it:
9:30 AM. OK, mystery’s over. Even the average CMJ Joe can see that 1) the jets were IN the Cirrocumulus cloud, and more importantly, the aircraft contrails consist of ice. Yes, that’s right, the passage of the aircraft has caused a phase change from liquid drops to ice crystals, a lot of them.
9:47 AM. Now those contrails are looking like real and icy Cirrus clouds. In this case they’re called “ice canals” but sometimes, when aircraft are ascending or descending and do this, they make round clear holes with ice in the middle, called “hole punch” clouds.
Lessons to be learned from yesterday’s supercooled clouds and the aircraft interactions inside them:
Cloud seeding works! You CAN make a supercooled, non-precipitating cloud produce a little precipitation that would not otherwise have occurred.
But in those situations where the clouds, say, are topping the Catalinas, they are often quite thin, and whether there is an economically worthwhile amount of precip is not known. However, an experiment targeting those clouds would be the perfect “baseline” one in cloud seeding to establish how much we can wring out of non-precipitating clouds. Things become kind of a mess when even randomized seeding takes on already precipitating clouds.
“Overseeding”, as here in these clouds when aircraft produce prolific numbers of ice crystals in a small volume, it leads to tiny ice crystals with low fallspeeds. Sure, they fall out and leave a hole, but they virtually never reach the ground except in one a in billion cases when the very cold clouds are real low, practically on the ground.
The Wegener-Bergeron-Findeisen mechanism produces precipitation.
Alfred Wegener, 1911, and later Bergeron3 and Findeisen in the 1930s, came up with the hypothesis that adding ice to a supercooled cloud results in the growth of the ice crystal at the expense of the droplets. They’ll tend to evaporate while ice is being added to the crystal via deposition of water vapor that was once liquid. So, an awful lot, maybe most of the precipitation that falls on earth, involves “mixed phase” clouds. This process has also been called the “cold rain process.”
However, let us not forget the two other processes that produce precipitation, the all ice process (no liquid required–helps produce “powder snow”, and the all liquid process, where cloud drops collide and grow into raindrops–the biggest measured drops in the world (about 1 cm in diameter) have formed soley through this process. It is likely that most of the rain that falls in tropical locations like the Hawaiian Islands and in hurricanes is due to this process even when ice is present in the top part of storms.
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Later, we had some Altocumulus castellanus clouds with virga as the moist level lowered, though they were long gone before they could provide us with a nice sunset:
2:32 PM Bands of Altocumulus castellanus approach Oro Valley from the west. These clouds, while based at just about the same level as the Cirrocumulus clouds earlier in the day had three things going for them to produce so much ice (right side of photo–and really, convert to Cirrus clouds). The cloud bases were slightly warmer (the TUS sounding suggests, -22 C), meaning more water was available to the cloud, something that would impact the drop sizes in the turrets of the Altocumulus clouds (left side of photo); 2) the tops were higher than the Cc clouds (ones that were paper thin) and therefore, slightly colder (probably about -28 C) than those of the Cc clouds, and perhaps as importantly, the drops near the top of the Ac turrets before they converted to ice, were larger than those in the earlier Cc clouds. The larger the droplets, the higher the temperature at which they freeze. So, ice is more likely to form in a cloud with larger droplets in it than one with tiny droplets in it even though they are the same temperature. That might explain the difference ice-forming behavior of yesterday’s very thin Cc clouds which mostly had no ice (until an aircraft came along in them) and these prolific ice-producing Altocumulus clouds, ones that converted to all ice. Just educated guesses here.
Still looking for scattered very light showers in the vicinity tomorrow as a Mr. Troughy goes by.
The End.
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1Through the oral history tradition I learned while viewing the Washington Husky meltdown2 at AZ stadium on Saturday from a Mr. Mark Albright that the Tucson weather balloon launch site has been moved from Davis-Monthan Airbase to the University of Arizona campus next to their weather department.
2Late in the proceedings, with about 2 min left and the Huskies starting a play, and in the lead, CM was visibly moved to jump up and say, “Don’t hand the ball off!”, as a gift to Arizona fumble occurred simultaneously. But, being bifurcated in his loyalties now that CM is in Arizona and not with the University of Washington, he had to be somewhat “glad” that the Cats maintained their somewhat suspect but great win-loss record.
3From the Historic Moments in Weather collection:
Your Catalina CM and Tor Bergeron meet for the first time in Goleta, CA, in 1968 at the headquarters of North American Weather Consultants. Yours for $2,100 dollars, today only. I remember thinking that his head was gigantic! No wonder he was so smart. CM, not so much.
Been away from you for a couple of days, wanting to see how you do on your own, perhaps see you grow in your cloud watching obsession, namely, that you want to name everything you see, as though you were Luke Howard himself. Hope you logged all cloud genera, varieties and species, 27 all told, over the past 48 h. You can bring your photo log books to the next meeting and CM will go over them with you.
Measurable rain chance still pretty reasonable for the window of Nov. 20-21st, too, as we have purported for some time here, but it will be pretty minimal.
The weather way ahead; a promise of substantial rains
However, as often happens, on the horizon is a substantial storm for Arizona, ones that have a habit of disappearing it seems as the foretold event gets closer. Here it is depicted below in plots from our cherished NOAA spaghetti factory:
Valid at 5 pm AST, December 2nd. Pretty cool, huh?Same spaghetti plot, annotated. Recall that these plots are ones where the model input has been deliberately errorized to see how big little errors make in the outcome of the model. Why do that? Because we know at the outset that our measurements are not perfect, and have all kinds of actual little errors in them. These plots are a way of seeing how robust a predicted pattern is, and those areas where the forecast is pretty reliable, is indicated by bunched lines (key contours of the airflow at 500 millibars, or around 18,000 feet above sea level in the mid-latitudes, lower near the poles, higher near the equator. Why do we use a pressure level instead of the pressure at a height? Go here. CM would like to see as well, in the 21st century, maps of constant altitude (3 km, 5 km, etc.) with the high and low pressures on them as we have on our sea level maps! Is anybody listening? (A google search just now could not locate, constant altitude pressure maps….)
While the above forecast of contours is two weeks away, and numerical models are often unreliable at those long horizons, we see that the red lines (not to be confused with political markers) have dipped down in great bunches over the extreme eastern Pac 12 Ocean, and continue all bunched up across Baja Cal and thence into Texas. In the plot above, the red lines represent a 500 mb height of 5760 meters, one that’s on the southern periphery of the jet stream. So, when its well south of us, our chances of rain are engorged. Recall, too, that the 5640 meter contour, just that bit lower in height, is associated with leading edge of rains in the central and southern California area–remember Brier and Panofsky, Some Applications of Statistics to Meteorology? Well, in that book you will learn that contour is what the LA weather service used to use as crib for when rain would occur in southern California.
I am sure you remember two things, maybe more than two. We have an El Nino in progress, not a great one, but an OK one, AND that El Niños strengthen the southern jet stream in the eastern Pac and across the southern latitudes to the east. So, we expect to see this pattern, one of a stronger jet stream in the sub-tropics carrying stronger disturbances as a result, evolving as the winter develops, that is, more disturbances in the lower latitude band of the jet stream (sub-tropical part). The plot above is a classic one for predicting that kind of regime, maybe with a bit of a split in the J-stream with northern and southern branches being pretty vigorous at this map time, and before, for that matter.
Valid at 5 AM AST, Monday, December 1st. Colored regions are those in which the model has calculated that precipitation has fallen in the prior 12 h.
The plot above, it has laid a foundation of credibility for what is show below, from IPS Meteostar’s rendering of our WRF-GFS forecast model output based on the 5 PM AST global data. It shows 24 h of substantial Arizona rains, including here in Catalinaland, at the beginning of December. You’d be pretty cool to inform your friends about this, ones who might be heading back somewhere after a TG visit to sunland1. (Besides, they won’t remember what you said anyway by the time December gets here.)
Valid at 5 PM AST, Monday, December 1st. Colored regions are those in which the model has calculated that precipitation has fallen in the prior 12 h.
Today’s clouds
Lots of pretty Cirrus.
The End
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1By the way, the Great Lakes are freezing over already, a month earlier than normal due to some astounding cold back there, so TG visitors from back East, upper Midwest, may look for reasons to stay longer. Well, at least until the rain and cold hit here.
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.
Beginning where we left off in our last chapter….that rain foretold here by the (affectionately) US WRF-GOOFUS models back a few days ago for the 19-21st for us only remains a possibility if you’re Canadian:
Valid at 5 PM AST, November 19th. Rainy system strikes Cal, on doorstep to AZ. You got yer subtropical jet stream crashing into the coast over southern Cal, a nice low off SFO, and plenty of rain predicted as far south as Los Angeles.Valid at the SAME TIME as the Canadian GEM model above, 5 PM AST on the 19th of November! This is a horrible prediction by our own best model, because it robs us of our rain! For rain here in the cool season, we have to have the jet stream over or to the south of us here in Arizona, and here the jet stream is over Oregon! There is no low off Frisco, either! No “Waterworld1” here.Areas of rain predicted for the 6 h preceding 5 PM AST November 19th by the US WRF-GOOFUS model. The low pressure center, rather than off Frisco, is way up there by Annette Island! Or is maybe that one inland in B C.
So, with “model divergence” like this, what’s a poor meteorologist to do? Well, here, at least, we go with the Smokers1‘ version absolutely. Look for a chance of rain here in Catalina land on the 19th-21st window, as has been suggested here a few days ago, and for that reason alone we are “staying the course” as President’s like to say. We’re not here to give you necessarily the best forecast, but rather a consistent one. So, in conclusion, look for clouds and a chance of rain around the 20th. Furthermore, to maintain consistency and build confidence in the reader by avoiding the emotional distress caused by “fluctuating forecasts”, we might be forecasting rain right up until it doesn’t happen!
—–Temperature note, or “Egad!”———
Got an e-mail from local pal, Mark A., that the -27 F recorded in Wyoming a couple of days ago was the lowest temperature ever recorded in the State for the whole month of November! How could that be? It was only 12-13th of the month! Incredible. Weather, global warming or not, are truly amazing!
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Yesterday’s clouds
Here are a couple shots of the Cirrus clouds we had yesterday and thge day before, so the header is not accurate. Not much going on lately, but those Cirrus clouds did make the sky pretty at times before racing off toward the eastern horizon.
6:39 AM November 12th. Cirrus clouds add color to the morning sunrise.9:46 AM. But which day? This is a surprise quiz for those aspiring to cloud mavenhood.
9:16 AM. Yesterday or the day before?
The End
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1Movie buffs of course, recall the great Kevin Costner movie, “Waterworld” and know that the villainous “Smokers” in that movie were Costner’s subtle nod to Canadians who smoke a lot. Pretty funny, really. I can’t believe all the pop culture information you get here! Its pretty incredible.
1I put in a second “1” footnote in case you missed the first one.
Data, except for the past summer, are from Our Garden down there near Stallion and Columbus. That last data point is from Sutherland Heights.
The End, except for what’s below.
Fall in the Sonoran Desert (the season)
These shots below from hikes/horsey rides on Friday and yesterday, FYI. Seemed a little greener than usual for this time of year probably due to those September and early October rains. I think you should hike or ride a horse/bike out there in the Catalina Mountains before the rains hit. Yeah, that’s right; its gonna rain in November1.
The End
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1Assertion subject to error. But check THIS out, from last evening’s run at 11 PM AST which I just now saw at 7:46 AM:
Valid at 11 AM AST Thursday, November 20th! Note “storm face” complete with eyes and a frown.
This was pretty neat, this forecast map from yesterday’s 11 AM AST WRF-“GOOFUS” (GFS) run. Look at all the rain barging into Arizona and Catalina!
Plenty of rain here in southern California AND Arizona! Valid at 11 AM November 20th.
What’s remarkable is that the ensemble runs made yesterday’s prediction of rain, one discussed here, quite the “outlier” of the rest of the “members” of the spaghetti plots, so one wouldn’t be expecting to see any rain for Catalina again!
But, here was that rain again, and this whole storm complex along the California coast falling mostly within that time period where over the decades there has been a tendency for storms to strike the more southerly locations between the 10 and 20th of November, something that was mentioned yesterday as a bit of a conundrum. Rain, though not as much, was shown again in the next run based on 5 PM AST global data, and due to that prediction of less rain, I am not showing it.
Below is a comparison of how the ensemble outputs (shown as “spaghetti” plots of a couple of key contours at 500 mb (around 18,000 feet above sea level) have changed since yesterday. To this observer, its been an unusually large change in where the grouping of those key contours are in just 24 h (they always change some, of course).
Notice how the blue (contours of flow pretty much in the heart of the jet stream) and red lines (periphery of it) have been shifted 10 degrees latitude and more southward from the first plot to the second, latest spaghetti plot, indicating that we’re going to be more in the storm track at that time, and the likelihood of a rain threat on the 19th-20th is more credible, less subjectively based as was yesterday’s take. Maybe subjectivity in forecasting isn’t that bad afterall…
Valid at 5 PM, Wednesday November 19th. Note how the red and blue lines bulge northward along the West Coast, suggesting a fair weather pattern.
Also valid at 5 PM AST, Wednesday November 19th. Blue lines (contours along which the wind blows from left to right) are now much farther south, and the red lines are now so far south they’re almost not in the map domain. Also, those red lines now do not bulge northward anymore, but rather are suggesting a broad trough along the West Coast at lower latitudes, completely different than the plots just 24 h earlier.
Finally found some rain for you. Took awhile. Came from the 11 PM AST global data from last night using the WRF-GFS model, our best. The rain falls around the 19th, “only” 11 days from now and during the “sweet spot” for southern California rain in mid-November, 10-20th, which gives it a few more percent of credibility than it otherwise would have.
BTW, there is virtually no support for this pattern from the NOAA spaghetti factory. So, all of the discussion below about an upcoming rain in Catalina might erroneous, based on a personal hunch about an outlier model run being the correct “solution”, one based on experience, and to HELL with spaghetti1, a study in forecasting subjectivity, etc.
Got that Bay Area rain timing info originally from C. Donald Ahrens, the big author of Meteorology Today and Essentials of Meteorology, both of which have about 400 editions out by now, while he and I were at San Jose State College University.
Don, a grad student then, and me, and undergrad, worked and sang together to Top 40 songs radiating from KGO-FM 2,3 in a little corrugated metal building there by the San Jose State football stadium back in the late 60s, and it was somewhere between songs that he told me about his findings.
Don had done a rain frequency study for the Bay Area for a local insurance company and it turned out that he found that it was somewhat more likely to rain in the middle of November than earlier or later in the month. That rain fell more more often than earlier was no surprise, but more often than later in the month was. Later I found that it was also true for southern California.
Sometimes oddities like these are referred to by big professors of weather, like Reid Bryson at the U of Wisconsin Badgers, as “singularities”, a weather pattern that tends to recur year after year around the same time of the year, like the so-called “January thaw” in the East which I don’t think happened last year.
So, ever since Don told me about the mid-November peak of rain in the central and southern parts of Cal, I have looked for it year after year and it seems to turn out quite often, and this November seems to be no exception, though the models were resisting this pattern for quite awhile before “giving in.”
Well, anyway where was I? It seems that the southern California rain is now being foretold for around 18th of November, and a day or so later it trudges on into Arizona. From IPS MeteoStar, a Sutron Company, whatever that is, this wonderful map:
Valid the night of November 19th-20th. Colored regions denote those areas where the model thinks it has precipitated during the PRIOR 12 h. So, storm has arrived here during the day on the 19th.
Some clouds
we have known over the past few weeks while CM was re-hydrating mentally:
Some ice for you on a warm fall day.Some ice for you on a warm fall day (virga from Altocumulus castellanus and or floccus)Pretty iridescence (or irisation) in a Cirrocumulus cloud.Pretty sunset, Altocumulus featured.
The End
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11The non-supportive spaghetti plot from the 00 Z (5 PM model run from last evening):
Valid at 5 PM AST Wednesday, November 19th. Arizona is in a low amplitude ridge, according to most of the “members” of the repeat model runs with itty-bitty errors deliberately put into them. I have rejected this plot and look for validation of this action around the 19th of November. You will not hear about it further if I am erroneous in this action!
2An odd, almost mysterious Frisco FM radio station with no commercials featuring, “Brother John.” We’d sing along to the Four Seasons, The Five Americans’, “Western Union” (about telegraph, the way people used to communicate before the Internet).
3 We both had quite a talent for falsetto it seemed at the time.
While living the big western life yesterday by riding a horse, me and my ridin’ pal, Nora B., came across some water flowing in the Sutherland Wash by the rusty gate on the east side of the wash that leads to Coronado National Forest land.
So, with with a 3-5 inch rain on the Catalinas, there WAS some water in the Sutherland here in the Catalina area. It was remarkable that there was no sign whatsoever of water having flowed at the Cottonwoods at the Baby Jesus Trail head on the north side of this flow (shown below), but water was flowing in it a few hundred yards farther downstream.
Nor was there any sign that water had flowed from our big rain in the Sutherland Wash at the back gate to Catalina State Park. In fact, we saw where this Sutherland Wash water disappeared just down from the rusty gate.
So, a lesson has been learned here about wash water flows: it can be flowing modestly between two dry points. Huh. Might not see this again for some time, and it will all be going away soon. Too bad so many of us have to pass hiking or horseback riding to these rare scenes today due to a necessary Pac 12 football TEEVEE vigil beginning just after 12 noon today and lasting through midnight I think. Kind of sad when you have to make choices between two equally worthy activities like these.
Cloudwise, I hope you logged the occurrence of distant Cumulonimbus clouds in the high country on the NW-NE horizon late yesterday afternoon.
The End.
9:18 AM. The Sutherland Wash near the rusty gate.9:54 AM. The apparent source of the water, the tributary Big Rock creek a few hundred yards south of the Baby Jesus trail head at the Cottonwoods.
