Cirrus fibratus, straightish fibers of CIrrus lacking a tuft or hook at the top, in this case toward the left. For fussy folks who detect a slight hook, Cirrus uncinus would be OK, too. Not really too important to differentiate between these species. Just shows its moist up there, and, like yesterday, there was a trough going by; air sliding up ahead of it, going down and clearing things off behind it (as happened late yesterday).Cirrus uncinus (tuft, center, with dangling strands of snow), something like the tops of deep storms on a rainy day. These little guys are also sometimes called “generating cells.” Vertically-pointed radars during storms show that those dangling strands of ice can make it all the way to the ground, the head, or cell, dozens of miles downwind by the time that happens since the wind is so strong at the tops of storms.Cirrus fibratus (foreground) and Cirrus spissatus where shading of the underside begins to occur in the distance.The rarely seen Cirrus castellanus, center, a cloud that can resemble the top of a Cumulonimbus calvus before it crumples back down into a flat fluff of ice.
The weather ahead
Tried to find some rain for you in the models, but only one had rain, and that was the low resolution (big grid spacing) Canadian GEM model posted here. It had the rainy panel (lower right) for SE Arizona calculated from last evening’s global data:
Valid for Wednesday morning, 5 AM, October 30th. The colored areas in the lower right panel are those ones where the model thinks it should have rained in the prior 12 h. Note heavier, red-blobs in AZ! How great would that be? Again this rain is the result of a westerly trough grabbing the moisture out of a tropical storm off Baja, a very “iffy” situation, to quote a term oft used by the much honored, late atmos sci Professor Richard Reed of the U of WA1.
Also, I am really learning about how much the WRF-GFS model likes to bring hurricanes and tropical storms into the Southwest. Yesterday’s model run at 11 AM AST, had another doozie coming up the coast in two weeks still having tropical storm strength and its about to pounce on northern Baja, southern Cal, and maybe AZ. Here is that depiction for your amusement, valid at 11 AM, Saturday NCAA football day, November 9th.
the stuff of dreams for Saturday, November 9th, 11 AM AST.
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The late Richard Reed, a man that did not mince his words. The nicest thing he ever said to me was, “Those guys have gotta be stopped.”
This is definitely not the same title as was a few days ago for a similar map, one also valid for Nov 3rd-4th. That title was quite different: “Not likely, but a wonderful map.” The rainy Arizona map back then from our best model showed a tropical storm and moist plume being drawn northward into AZ.
Almost the exact map as that one a few days ago has shown up again out of the blue, if you can say that when you’re talking about clouds and precipitation. There’s been nothing like that former map since that first time it showed up, and, in view of how odd it was, you tend to write it off as something you’ll not see again. But there it was again, now only 10 days out.
Below, the happy, rainy AZ map churned out by last night’s model run based on global data taken around 5 PM AST yesterday ( from IPS MeteoStar):
Model output valid for 5 PM AST, Monday, November 4th. Shows tropical storm remnant being sucked up toward Arizona with lots of rain already here. Green blobs denote where the model thinks rain has fallen in the prior 12 h, which here is the entire State of AZy!
Below is the pattern aloft that steers (hahaha) all that moisture into our water-challenged State, one that has a lot of steers.
HOWEVER, this rainy situation requires a lucky conjunction of a Pacific trough coming in out of the Pacific onto the southern California coastline, while a tropical storm/former hurricane is off Mazatlån at that same moment. If these two features of interest are just about anywhere else than is shown here in these model projections, forget it.
The flow pattern in the middle of the troposphere, around 15,000 to 20,000 feet above sea level. Yep, that’s right, half the air is gone by the time you get to only about 17,500 feet!
The first time this rainy map was shown for Nov. 3-4th, back about five days ago, the chances of it actually happening were probably somewhere around 0.2 percent. Just too much had to fall into place. Coming up twice, however, jacks the lucky numbers up to, oh, maybe to an 8 percent chance of actually happening as a wild guess. Not a great chance, but one that’s trending upward. You know, after the rainless October that’s about to finish up, we really deserve this storm in early November. The NOAA spaghetti factory has good support for a trough along the California coast at this time, so its likely THAT ingredient will likely be in place on November 3rd-4th.
Yesterday’s clouds; yes, there were a couple, some patchy Cirrus and a little band of Altocumulus, some of the latter trending toward lenticularis-ee ones. later on. Here they are.
2:37 PM. Patches of Cirrus drift across the southeastern sky.3:51 PM. Lines of Ac perlucidus streaked across the sky in the afternoon, soon to disappear.4:52 PM. Ac len below a patch of Ac perlucidus.
Last evening’s model1 run based on global data from 5 PM AST yesterday, gave us this, the remnant of a tropical storm barging into Arizona on November 3rd, just after our rainless October closes out:
Valid at 5 PM AST, November 3rd two weeks from today.
As an expert “spaghetti” decipherer, you can easily see from the map below that there’s not much chance of this happening though its not completely impossible. Too much “noise” in the pattern around here (lines aren’t bunched like they are off Japan and in the western Pacific). I just posted the map above because its the first one in SO LONG that had any Arizona rain on it, that green and blue stuff on the map above.
Valid at 5 PM November 2nd, the day before the map above, but close enough.
Who knows, maybe there’ll be a cloud over us one day again, too.
Of note… unusually cold air for October is poised to rush into the eastern and central US in several waves during the next two weeks; those events have a much higher probability of occurring according our venerable NOAA plots of spaghetti like the one above. Likely will see cold air refugees beginning to bail to Arizona in their droves from eastern units of the country as October low temperature records fall.
Its great to be where other people want to be.
The End.
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1Namely, the Global Forecast System-Weather Research and Forecasting (GFS-WRF) model, pretty much our best.
Some rare drizzle precip1 fell yesterday. Suggests clouds were pretty “clean”, that is, didn’t have much aerosol loading and the concentrations of droplets in them was low (likely less than 100 cm-3) Also likely, in view of the recent strong winds, some of the aerosols in those clouds might have been large dust particles2 rather than those due to just “smog” and other tiny natural aerosols. Large dust particles can not only influence the development of ice at higher temperatures than normal (above -10 C), but is also known to aid the formation of rain due to cloud drops bumping into each other and sticking together; collisions and coalescence because large dust particles can accelerate this process by forming large initial drops at the bottom of the cloud where drops first condense. Here, drops are nearly always too small to bump together and join up unless clouds are deep, like our summer ones, and ice is going to form anyway.
So, yesterday, was a bit of a novelty. Some photos and story telling:
1:34 PM. Drizzling from Stratocumulus!
1:35 PM. Drizzling here. Hope you noticed and wrote it down. I remember how excited I was in 1986 when I was in Jerusalem and it drizzled! I did not expect to see drizzle there, and I remember how I screamed out, “DRIZZLE?” after putting my hand out the window of the modest hotel I was in. In those days, the cloud drops were reported to be too small by researchers there to form drizzle in them. Yes, Mr. Cloud Maven person was the first person in the world to report in a journal article3 that it DRIZZLED in Israel! One of the great things about blogging is that you can write ALL of the things that you like to read about yourself, and this one is no exception. I am really enjoying today, reliving past efforts and accomplishments since there don’t seem to be too many ahead….The late Jack Russell, flight engineer, listening to Art tell another cloud investigation story.
2:43 PM. Cumulus humilis field over Saddlebrooke.3:06 PM. Drizzle precip just a memory. These clouds too shallow to rain via collisions, and too warm to form ice.
Looking ahead….
Mods paint dry weather for the next 15 days, and so yesterday’s disappointing “trace” (don’t recall here that Mr. Cloud Maven person had predicted at least 0.02 inches!) may be it for October. Phooey.
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1Drizzle: Fine (size range, 200-500 microns in diameter drops) close together, that nearly float in the air. Very difficult to bicycle in drizzle even with a cap or big hat. Fallspeeds, just a few mph. Smaller sizes can’t make it out of the cloud, or evaporate within a few feet almost if they do. Even true drizzle occurrences, you can’t be too far below the base of the clouds or those tiny drops won’t make it down to you.
2What is a “large” dust particle in a cloud? Oh, 1-10 microns in diameter, real rocks compared with the other stuff normally in them. So’s you get a drop that’s already pretty large as soon as condensation takes places. And, if the updrafts are weak at the bottom, then only them big ones might be activated, keeping the whole cloud’s droplet concentrations low! Happens even in places in the middle of huge land masses where in Riyadh, Saudi Arabia, we saw this happen on a dusty, moist day in shallow Stratocumulus clouds. They developed some drizzle drops. I was with the National Center for Atmos. Research on a field project then.
31988: Rain from Clouds with Tops Warmer than -10 C in Israel (Quart. J. Roy. Meteor. Soc.)
6:09 PM. Not so long ago, this kind of thing happened at 7:09 PM… Altostratus here; too thick to be Cirrus.
Some rain to fall on Thursday, most likely between 5 AM and 11 AM. Both the US models and the Canadian one have rain for us now, not much, but likely measurable. Best personal guess from the “pattern”: between 0.02 and .20 inches. This “pattern” is one where the Catalina Mountains are at the southernmost extension of much heavier rain/snow to the north, the clouds bank up on the west side of our mountains, and little Catalina-its-not-Tucson gets measurable rain whereas Tucson and places south do not. Jet core at 500 millibars (18,000 feet or so above sea level) will be passing just about overhead Thursday morning, and the wind at cloud levels during precip southwest to west-southwest. In the cooler half of the year, that jet core usually demarcates a sharp line between no precip (to the south) and precip on the north side of it when the core is oriented west to east. From IPS MeteoStar, this rendering for mid-day Thursday for illustrative purposes:
From last evening’s 5 PM AST global data, the WRF-GFS model forecast winds at 500 millibars at 11 AM, Thursday, October 10th, Julie B’s birthday. I liked her a lot (late 70s) but it didn’t work out. Recall sea level pressure averages 1013.6 mbs and so this level is about halfway through the mass of the atmosphere above us, and around 18,000 feet above sea level. Likely that any precip here is ending here about this time as the trough over us shuffles off to ‘Braska and vicinity.
Adding to the rain excitement in the meantime will be scattered interesting clouds, windy conditions in the afternoons, and much colder air arriving during the daytime on Thursday.
To keep you occupied while waiting for rain, I now present an enigma. I shot this during a return flight from our B-23 aircraft as it ferryied back to Paine Field in Seattle after a study of emissions from the Mohave Power Plant near Kingman, AZ, September, 1983. Not sure of the location, might be eastern California or southern Nevada. On these kinds of ferry flights after a big field project, often with two bumpy, low-level flights a day, you don’t care where you are on the way home, you just wanna be home!
Might be a satellite calibration field of some kind. Even today this grid in rough terrain still amazes:
Late September 1983, over eastern California or southern Nevada. Not sure; half asleep.
Hot off the Canadian presses from last evening’s global data from 5 PM yesterday, this exciting depiction (from Enviro Can) for Friday afternoon, the 10th. Note green and yellow regions in all of the SW, lower right panel! Note big upper trough over Vegas, upper left panel. Its all good, and, this being the 5th, its only a few days away!
Valid Friday afternoon at 5 PM AST. Note “tropical river” emanating from a tropical storm or depression off the tip of Baja (colored regions in lower left panel). No reason to be depressed if this happens.
But let’s look deeper….deep into the heart of the US WRF-GFS model for the exact same moment in time, shown below:
Also valid at 5 PM AST on October 10th from IPS MeteoStar. Perhaps the US model is sequestering rain for Arizona…. NONE, as in nil, is indicated from a model run generated at the same time as the Canadian one above! As you can see from the arrow, there is NO RAIN indicated for most of Arizona as a very strong upper level trough goes by. How bizarre is that? Something’s goofy here and its not just me.
What caused this model bifurcation?
For one thing, the US mod sees no tropical depression off Baja, and our hurricane center is very skeptical that any tropical development will take place south of Baja, one that would move NW or N and send a moist plume up into a trough positioning itself over southern Cal on the 9th. US mod has NO tropical moist stream coming out of the eastern Pac ahead of a trough over southern Cal at all, whether there is a low down there or not. Boohoo.
So, any rain here in Catalina would be with the usual passage of the jet core and in the cold Pacific air behind the cold blast headed our way on the 10th-11th. And that rain would be very light, likely less than a tenth of an inch.
The Canadian model, sadly, has to be considered a little goofy right now with its copious SE AZ rains, and widespread rain/snow over the rest of AZ, too. It would be good to inform your neighbors that you are thinking the same thing about the Canadian model, i.e. that its a bit looney as well in case they saw it and are touting a lot of rain on the way without really looking into things. Embedded editorial note: A lot of people vote like that, too, I think; also read health claims in magazines without looking at the peer-reviewed literature, taling with their doctor, examine the results of double blind, randomized trials, that kind of thing on which we base the whole edifice of medicine on. No, they’d rather read on the side of a health pill food, “these claims have not been evaluated by the FDA” and then take the stuff anyway and enjoy the effects of a placebo, which, if you believe in it, can be pretty good.
No doubt the reports of low temperatures in Arizona with this coming big upper trough on the 10th-11th, and snow in the high mountains, will spur a flock of snowbirds to migrate south. It’ll be windy and dusty, too, as it usually gets ahead of the passage of the cold front with these big troughs. That will be interesting, as well as all the cloud forms that start to show up with it.
Note: I’d show you some NOAA spaghetti so that we could get a little more on this model discrepancy, but its been sequestered from me, as you will see here. In the meantime, will hope for Canadian vindication in the days ahead.
Here are the updated plots from the Our Garden location on Stallion where a continuous record has been maintained since way back in 1977 when the Sex Pistols, led by Johnny Rotten, were beginning to alter the face of pop music and pop culture and trigger an alternative music and fashion scene called “Punk.” Let’s see what John Lyden (aka, Johnny Rotten) had to say some years later after the SP years…
Below are the water year data for 2012-2013 ONLY from the Our Garden site, not a mixture of obs from MY gauge and theirs (which could cause “heterogeneities”, as I have posted before. Not much difference, really, between our sites, but it makes for a cleaner dataset, a “homogeneous” one. Thanks to the folks at Our Garden, Jesse, Wayne and Jenny, for letting me update their precious data into a spreadsheet lately. State climo wants it, too.
One difference that stood out this year was that Our Garden was clobbered by a few summer storms that we didn’t get and their water year total is 2 inches more than here (11.08 inches) in Sutherland Heights/Catalina, just a couple miles away.
So, here are the “homogeneous” data back to 1977 FYI:
I don’t place too much credence in a continuation of a downward trend, lately obdfuscated some by juicy summer rains. These kinds of things, even assuming some slight GW influence, usually reverse themselves rather suddenly with a burst of wetter years such as we see at the beginning of the Our Garden record in the late 1970s and early 1980s. Some of that was fueled to some degree by El Ninos, sometimes called “Eel Nino” due to its monstrous effects on Cal coast and the SW in general. Here’s what “Eel Nino” looks like when it occurs:
I wonder if you caught it? Fell between 8:10 and 8:12 AM. Very isolated, and pretty small drops. If you weren’t driving in it, or outside, you would never have known this happened. But observing and reporting events like this is what makes us who we are, you reader of CM. We take pride in seeing and observing what others don’t.
8:12 AM. Photographic documentation of the total rain event on a car window, zoomed view. The largest raindrops are about 1 mm in size.
Before the rain hit, some two or three RW– (weather text version of “very light rainshowers”) began to fall to the SW of us from that deck of Stratocumulus clouds. Must have been where the tops were higher than anywhere else. Here’s the first sign, and upwind of Catalina, that you, as a CMJ (cloud maven junior) know to pull your car out of the garage. (BTW, thinking about having a CMJ cookie drive next month…so look around for your best recipes.)
7:42 AM. A full 30 minutes before the trace event in Catalina, a weak shaft of rain is observed on Twin Peaks, part of a broken line of sprinkles-its-not-drizzle rain.
It may seem strange, a non-sequitor, for those blog passersby to be talking about taking your car out of the garage or carport if a slight amount of rain might occur, as was the case yesterday. Here’s the “skinny”, as we used to say in the last century when we were young and could do things: a “clean” car, one that been wiped of all evidence of prior rain drops, but one having a thin coating of dust (you don’t have to apply a thing dust layer, its goes with the territory here) is great as a “trace detector.” And for us, CMs and CMJs, observing a trace such as yesterdays, when ordinary observers miss it (fumble the ball), is like hitting a low outside slider from former Husky pitcher Tim Lincecum, for a game winning touchdown. Or Boise State beating Oklahoma in a bowl game.
Why not just use the radar instead of parking your car outside and if the 24 h depiction of precip shows an echo over you, just mark yourself down as having a “trace”?
That would be cheating! Besides, some echoes seen on radar are only aloft.
And what if you’re in a “data silent” zone, where the radar beam is blocked by terrain, or is too far away? You’re adding unique information with your trace. Sure, nobody around you really cares if you had a trace or not, but, what the HECK.
8:01 AM. Heavy looking cloud produces sprinkle on the Tortolitas. Looks so dark partly because of the time of day, and partly because there was a fair amount of aerosol in the air. When higher aerosol concentrations get into clouds, it causes the drops in them to be small, and when small, they reflect more light off their tops and the bottoms appear darker. But it also indicates that the clouds are thicker than surrounding clouds, there’s a mound on the top. Still, among those higher droplet concentrations must have been drops large enough to collide and stick together and become small raindrops.
Did the tops reach -10 C or so to form ice and cause this shower? Nope. Capped out at 0 to -5 C, so almost impossible to have had ice form to cause our sprinkles. Check this sounding from the WY Cowboys, who are off to a good season BTW.
The Tucson sounding for 5 AM AST yesterday morning during our cloudy conditions.
In examining this TUS sounding closely, its good to remember that we are NOT Tucson, but in Catalina. We are 14 miles from the city limits; have a road sign that sez so. “Hey”, we aren’t even on the same side of the mountains as is “Tucson.” In fact, you have to go through the city limits of Oro Valley to get to Catalina! Only the Post Office thinks that Catalina is in “Tucson.” OK, got that in…
And, during the cooler season when troughs go by, as yesterday, the temperature profile from Tucson balloon is not accurate for us here in Catalina; its always that bit colder to the north and west of the balloon launch site for days like yesterday. So, like a chef, adding that bit more of butter or garlic, OUR sounding should be tweaked from the TUS one to show slightly higher and colder cloud tops, probably near – 5 C, not at ZERO or slightly cooler in overshooting Cumulus/Stratocumulus tops as would be expected from the Tucson sounding. Also, since it sprinkled at 8 AM, and not 5 AM, its also likely that clouds tops were going up some as the trough from the west approached yesterday. So there are lots of possibilities.
Sure wish we’d had a PIREP! (Texting form of, “Pilot report”). Any CMJ’s out there have an aircraft that we could take up and kind of poke around up there, see for sure what really happened instead of “hand waving”?
Absent aircraft reports, I am going to say that almost certainly yesterday’s sprinkle was a case of rain formed by “collisions with coalescence, or via the “warm rain” process (called that because it doesn’t have ice), sometimes called here, “coalision” rain. Very unusual in Arizona and, you can see that if you have to park your car outside to see how much came out of a cloud producing rain through “coalision”, it doesn’t amount to much.
You know, this is a great story for you. First, you observe rain that no one else did, or even cares about, until maybe you tell them it was almost certainly caused by collisions among cloud droplets, and then watch their eyes bug out!
Had some spectacular highlights again on the Catalinas, and also evidence of the aerosol loading as we say, in the crepuscular rays (colloq., crepsucular) shown below.
8:03 AM. Evidence of smog, maybe some dust, too, aka, aerosols that were getting into our clouds yesterday.8:04 AM. Gorgeous highlights continuously moved across the Catalinas. Hard to stop watching, snapping photos like mad, HD filling up, not much room left, gasping for more empty sectors now.
1:39 PM. Its all over. Only a field of small Cumulus (“humilis”) are left. Photo taken from inside a horse corral to give it a western flavor, make it more accessible to reader, maybe make you feel more comfortable after a heavy dose of “science-hand waving” today. Note rust on panel piping; adds artistic content. “Rusty corral and Cumulus humilis”; yours today only for $2,000.
Since there is STILL no rain indicated for the next 15 days in the models, just dry (for now) trough passages, I may have to discuss yesterday’s sprinkle again tomorrow. Thinking of a title even now: “That sprinkle; more insights on what happened.” Yeah, that should do it.
Breezy, deep blue skies were pocked with Cumulus humilis (“humble”) but as the afternoon wore on, they became more numerous, and spread out to nearly fill the morning’s clear sky, while remaining “humble”; about the same depth, 1,000 to 1,500 feet, max. Cloud tops were above freezing, so no chance to form ice and snowflakes, which would have fallen out as virga. Nor was there a single Ac lenticular, as opined here that there might be one yesterday.
These kinds of days with scattered clouds producing shadows on our spectacular Catalina Mountains is one of the most mesmerizing. If you can, you want to be somewhere where outside where you can see those shadows trek across our mountains, their rocky faces highlighted and then dimmed, while another portion lights up highlighting some other characteristic of those mountains, particularly in the late afternoon when the sun light is that bit richer (due to traveling through a greater path of the atmosphere as it sinks toward the horizon and more of the harsher, shorter wavelengths of white light are scattered out). Ask any photographer or artist.
And its no wonder we draw so many visitors in the cooler half of the year when there are so many days like yesterday; no rain, pleasant temperatures, but astounding, simple beauty just in the passing of a cloud shadow on a mountain.
3:11 PM.3:11 PM, looking farther toward the north. So pretty. You can just sit there and watch these ever changing scenes for hours. “Less doing, more watching.”5:15 PM.5:33 PM. Even our dreaded cholla cactus can have so much beauty in the right light.4:19 PM. Wonder how many of you noticed this line of small Cumulus clouds, called a “cloud street”? At first I thought it was caused by a bounce of the air going over and around Pusch Ridge, but later it was clear it had origins far to the south.5:29 PM. “Cloud street” still going, but you can see the origin is not much related to Pusch Ridge as it shifted westward and extended overhead and downstream into Pinal County. The clouds were filling in pretty fast at this time, but barely deepening.6:07 PM. While the sunset itself wasn’t spectacular, the lighting on the mountains was. Aren’t you glad you live in Catalina?
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In spite of overcast Stratocumulus clouds right now in the pre-dawn hours, there are no echoes on the radar anywhere near us. Boohoo.
And, if you’ve read this blog, and studied its contents, taken all the quizes, you know its because the tops aren’t cold enough to form ice (generally requires -10 C, 14 F here), pretty much required for rain here in old Arizony. Of course, some of our citizens are older than “old Arizony” as a State, which is pretty darn amazing, so maybe it should be, “not-that-old-Arizony”, to depart from whatever it was I was going to say before thinking about “Arizony.”
Now, back to weather…. Looking at the satellite and radar from IPS MeteoStar, it would appear that there are enough clouds around that a sprinkle is possible before noon as an upper trough goes by today. The air will be getting colder aloft, and there appears to be a line of colder clouds in a band right now in western Arizona, maybe ones cold enough to do that. Measurable rain is a very remote possibility, however.
Another trough, very similar looking to this one today, with a blast of cooler air comes through on Friday, October 4th, but like this one, looks dry. So, we have two pretty nice weekends in a row ahead of us as far as moderate temperatures go, and more great cloud shadows.
No rain for SE AZ in models for the next 15 days. Dang.
