About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
Author: Art Rangno
Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.
Here, from last night. Has a great solution to weather: all AZ rains beginning the NW portion of the State late on the 21st, spread over the rest of the State the next day (22nd) and continue into the 24th. Not looking at other models since they might be different.
Incoming Pac trough (bend in the upper level winds) curls into low center over southern Cal, then takes a couple of days as it slowly spins east over the US-Mexican border allowing beau coup moisture to flood into AZ from the south.
The End, and pretty easy today; saw what I wanted to and went with it.
A couple of Pima County gauges reported measurable rain yesterday or overnight, but that was about it. But it was a fabulous cloud day yesterday. Heavier spotty rains, one USGS station indicating over an inch, fell in the central and northern mountains, which is good.
Below, a rehash of yesterday’s great variety of clouds.
7:48 AM. Altocumulus lenticularis clouds beyond the mountains to the SE of Catalina. Lenticular clouds indicate a stable layer of air, one resisting being pushed up, the opposite of what the slender Cu below indicated. So, an usual sky for us yesterday morning.8 AM. Towering Cumulus atop Ms. Lemmon indicated how unstable the air was just above mountain top level. Underexposed for dramatic silouhette look. The smooth top on the right would be Stratocumulus lenticularis, again an odd juxtaposition.
10:37 AM. Then you had your Altostratus mammatus/testicularis.3:08 PM. Your Cumulus mediocris topping the Catalinas with a few Altocumulus above; nice shadows and sun quilting.
3:09 PM. And you had your “weak” Cumulonimbus capillatus clouds to the north.
4:19 PM. Here’s a better shot of the Altocumulus perlucidus (here) top side.
4:33 PM. Nice example of glaciating smaller Cumulus remnant north over Saddlebrook. Likely some sprinkles reached the ground under that ice plume. As you know, takes ice to get rain in AZ.4:34 PM. More sunlight and shadow drama due to Stratocumulus and Ac perlucidus above. Was indoors socializing so didn’t see sunset. Hope it was a good one. I am beside myself thinking about how happy you were seeing all these kinds of clouds in one day!
The weather ahead
Models beginning to act quite well now. A little rain is foretold for Catalina and environs on the 21st of November, but Enviro Can make that storm look more significant and slower to move in, on the 22nd. Still two mods, both having some precip? Its all good. First, for your viewing pleasure and because it portends more rain, from Canada, this:
Valid for 5 PM, November 21st. Low and lots of rain shown banging into Cal. Would be here about 24 h later, or on the 22nd.
Also valid for 5 PM AST, November 21st, this depiction of the flow at 500 mb.
An aside: the Canadian model tends to have a westward bias, that is, a storm is foretold to be farther west a few days out than it turns out to be, something I’ve learned since becoming a forecaster yesterday (hahaha, just kidding, if anyone’s reading this far). So you have to figure the Enviro Can depiction of a trough off Frisco, Cal, is really going to be inland that bit. The US mod output shown above, has this same trough going more overland before it gets to us than the Canadian one, and so there’s less cloud water in it by the time it gets here. Root for the Canadian “solution”!
Farther down the road….more illusory water on the hot highway?
And, of course, a heavier rain is once again over Catalina and vicinity as November closes. This model really likes Catalina and SE AZ! Check it out:
6:52 AM. Altostratus with modest downward hanging mammatus1 bulges under lit by rising sun above the Catalina Mountains. Altocumulus clouds are in the background. Was a magnificent sight.6:57 AM. Mammatus protuberances more evident here, and quite lovely I thought. I seem drawn to mammatus formations.
The weather way ahead
Well, the WRF-GOOFUS model has lots of rain for us again as November closes out, with the model rain amounts foretold in November for Catalina now totaling over two inches, or about twice normal. Its been great model month of rain for us. Below the latest rains foretold, beginning on the 27th, continuing into the 29th. Here from IPS MeteoStar, these renderings from our best model, based on last evening’s global obs taken at 5 PM AST:
Valid at 5 PM, Wednesday, November 27th.
Vallid on Thursday, November 28th at 5 AM AST.Valid at 5 pm November 28th. Green areas denote areas where the model has calculated that rain has occurred during the prior 12 h.Valid at 5 AM AST Friday, November 29th.
There is some evidence from the NOAA spaghetti factory that churns out those spaghetti plots that a big change happens in the last week of November, so rain at the end of the month, two weeks from now, is not out of the question. This rain pattern results from a stagnant upper low SW of us which you can see here.
What about the weather immediately ahead?
Global pattern shifting like mad today due to what we call, “discontinuous retrogression” caused by low cutting off out of the jet stream in the central Pacific. Troughs/ridges jump westward almost overnight when this happens. Highs disappear overnight as is happening right now over the whole West! Very exciting, except in this case, while a trough blossoms overnight replacing a ridge in the West, its amplitude (how far south the jet stream in the trough gets) doesn’t seem to be enough to provide us with rain here in Catalina now. Remember that winter rain here is nearly ALWAYS associated with a jet (at 500 mb) to the south of us.
This drastic change in pattern often only lasts a couple of days, too, before reverting to “same old same old” as we had, fair and warm. I wanna cuss here.
The foretold development of a trough in mid-month in the West was a huge, and strong signal, you may recall, in our “Lorenz plots” (I am hoping this name catches on; he deserves it), those balls of yarn I show every so often. So the trough and cold air getting here to SE AZ has been “in the bag” for more than 10 days in advance, according to those strange plots.
However, the rain here in the actual model runs has come and gone in them as mid-month approaches, and lately, there ain’t been nothin’ here. At most, a few hundredths it would now seem, and most likely, nil.
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1Gender-specific naming cloud variety convention: if male, as in the case of the writer, this cloud formation is deemed, “Altostratus mammatus”; if female, the proper name would be “Altostratus testicularis.” Its part of an adjustment similar to the one when only female names were used for hurricanes, and doing that, it was felt, lent a kind of stereotype to female behavior/character. So, male names for hurricanes were introduced by NOAA in the 1970s to “even the score”.
Some nice CIrrus spissatus and the rare Cirrus castellanus yesterday (something I say a lot here in old AZy). Here is half hour sequence of a patch of heavily precipitating Cirrus spissatus, kind of a cloud oxymoron. I thought it was pretty spectacular even if you don’t care one wit about it. (Hahaha, “wit” instead of “whit.”)
Those Cirrus clouds were up at about 35,000 feet above sea level, at around -50 C (-58 F), but snowing like mad. Don’t let folks tell you its too cold to snow; usually happens that way because here on the surface there’s a high pressure over you, the sky is clear, to wit; a fair weather pattern, and that’s why its not snowing here on the earth when its -58 F, except maybe when there’s a ice haze called “diamond dust“, tiny ice crystals floating/glinting in the air.)
8:48 AM. Cirrus spissatus on the left with the little snowstorm trailing off to the left will pass overhead of Basha’s parking lot there on Oracle in about half an hour, a prediction made in hindsight. 9:07 AM. Taken while not driving down Equestrian Trail Road to Basha’s supermarket.9:21 AM. Basha’s parking lot. Snow, composed of single crystals, not flakes or what we called “aggregates” because they don’t stick together at such low temperatures, pours out of this really cold cloud. The single crystals in the trail would be bullet rosettes, a complex looking crystal consisting of hexagonal columns that stick out from a center point. How much snow falls out? Just a dusting. You could blow it away off any surface. When flying through these icy clouds toward the top where the crystals are simpler, there are sparkles and glints when the sun hits the crystals just right. Very pretty.
The day ended up with lower Cirrus and few Altocumulus clouds with virga as the dry air aloft moved in, providing the clear western horizon that allowed the sun to highlight our clouds. That great sunset, as much as I could see anyway being “on the road” here:
5:37 PM. Heavy Cirrus (spissatus) or Altostratus patch, either name OK, with Altocumulus on the far right horizon.
The weather ahead
Mods still showing rain in the area on Sunday the 17th pretty consistently now. And as we saw from the “errorful” NOAA spaghetti maps yesterday, a trough with cooler weather, clouds and scattered precip is pretty much in the bag for that time period (16th-18th). Can only hope that we get something measurable here. But, even without rain, those days will be pretty ones with Cumulus clouds around.
Here, in chronological order, yesterday’s pretty sunrise, as today’s wil be, too:
6:46 AM. Pretty Altocumulus just on the other side (downwind) of Ms. Lemmon.
6:49 AM. Walkin’ the dog under pastel skies and virga from Altocumulus at -27 C (-16 F), about 21-22kft above us. 6:57 AM. Dog inside eating while Altocumulus with virga continues to highlight north sky.
7:32 AM. Newly formed Altocumulus perlucidus, sometimes called, “mackerel1 sky”, no ice evident. Even at very low (not “cold”, BTW, to be technically correct) temperatures, ice free clouds can occur. Sometimes its momentary, sometimes not, these clouds appeared to evaporate without producing ice.
More pretty clouds coming in today. Look up now, or see sat images here.
Cold blast dead ahead after warm spell, rain iffy here, pretty certain in Cat Mountains. Cold air arrives on the 16th-17th now. Has very strong support in the NOAA-Lorenz spaghetti plots.
Rain is with another deep trough is shown here in last evening’s model run for the 21st. I’d be VERY excited normally, but when YOU look at the NOAA spaghetti, you’ll see that it has very little support and must be considered mostly fantasy, an outlier model result, one not likely (though not impossible) to verify. Once again, precip center is depicted in this goofy run as over my house (us). Here’s that rain as rendered by IPS MeteoStar:
Valid for 5 PM AST, November 21st. Not where heaviest precip is indicated again (arrow).
…and maybe points north, too. Lately models have been foretelling rain in Catalina on the 17th or 18th. In case you don’t believe me, here’s the precip forecast from last evening’s (00 Zulu) WRF-GOOFUS1 model run for the morning of the 18th as rendered by IPS MeteoStar:
Valid for Monday morning at 5 AM November 18th. The colored areas are those in which the model has foretold rain during the previous 12 h. As usual, the heaviest amount is foretold for my house here in Catalina/Sutherland Heights.
What are the chances this will really happen so many days ahead? Pretty good. Let’s check out the “Lorenz map2” below:
The Lorenz map, a name I made up but he deserves it since he came up with the Chaos Theory due to which such maps like these are produced by our computer models; where little, itty bitty things can feed into the system and alter the whole thing, like the cliche of a butterfly flapping its wings in Brazil and affecting a tornado in Texas later, as a friend said in a SEA Times article a few years ago, a friend, BTW, that I played softball with on the Dept team and could really hit the long ball3… Oops, where was I? Oh, yeah, this map is valid for 5 AM, Monday, November 18th.
Cold air in Catalina? Having to put your jacket on for a few days? Its in the bag.
Rain? No doubt showers in the area with a pretty low snow level on the 17th-18th, but, with the long overland trajectory as presently indicated, not much, maybe a tenth of an inch or so, kind of marginal.
Yesterday’s clouds, high ones
There was some iridescence in a patch of Cirrocumulus about mid-morning, and then what might have been a bit of a parhelic circle in a patch Cirrus. That was it. More interesting clouds today as streamers of moist air at high levels sporadically invade Arizona, and today should be one of those. Get cameras ready!
10:56 AM. Sublte bright, slightly curved line in the upper part of this photo of a Cirrus cloud patch may have been a “parhelic arc.”
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1 As the Global Forecast System is affectionately known.
2I think E. N. Lorenz deserves it, a map with his name on it that we currently call “spaghetti plots”, or by the uppity “model ensembles” name. You put little errors in at the beginning of the model run and see how different the end results are. Not too much effect at the beginning because the errors are so small, but usually end up producing a ball of yarn after kitty played with it, as one reader wrote, after a couple of weeks, meaning that the reliability of any specific prediction at that time is nil. You see, all instrumentation has some error factor, so we never really measure the exact state of the atmosphere. This is a technique of adding little errors is to see how much they can affect the outcome. Sometimes, when something really POWERFUL is out there somewhere, those little errors don’t have much of an effect, and that’s when we can make a pretty good prediction for more than a week out.
3In case you don’t believe me again, this time that I actually played on a softball team with someone that might be asked his opinion on something by a newspaper reporter from the Seattle Times, here is a picture of Dr. Nick “Blaster” Bond, my teammate. I took this picture him because I really liked him, and we both liked to play on teams with girls who could really play, too, then we would win co-rec titles because of how well THEY played. It was great! Nick always wore those ripped short-shorts no matter how cold it was, even if it was raining.
Famous scientist, quoted in newspapers, Blaster Bond, looking askance at some lollipop softball pitcher, about 25 years ago. Not the same Bond responsible for “Bond Cycles” in paleoclimate proxies, though I wish he was because then I would be more important as a person having more important friends I could mention.
We have a monthly rain total that’s not zero! But will there be more this month? Stay tuned until November 30th! (Nothing imminent.) In the meantime, a very pretty blue sky day today pocked with residual Cumulus clouds, maybe some virga. There’ll be nice cloud shadows and sun on the Catalinas again today.
In the meantime, here are the Pima Country reports for last evening’s rain. The heaviest amount seems to be at our end of the Catalinas at Pig Spring, with 0.39 inches. Nice.
Yesterday’s clouds and why
Not exactly the way they were supposed to go, the ice cloud shield WAS on the horizon to the NW at mid-day but didn’t advance over us, but rather fizzled out. That’s OK. What was left of it enhanced a spectacular sunset through the rain.
The Cumulus clouds were the stars of yesterday, doing something in the way that the old rock band, Jethro Tull used to do. The members of JT would come out on stage as roadies, fiddle around with equipment for awhile, then suddenly turn around and began playing! Oh, who can forget Jethro Tull and that Aqualung album that roiled the rock waters back in 1971 by interrupting heavy, driving rock with acoustic interludes and flute playing (!!! )? What were they thinking?
Well, our Cumulus clouds pulled a fast one, too, after hanging around, fiddling around not doing much, then blammo, here comes the ice around 4:30 PM, followed by an eruption into an honest-to-goodness Cumulonimbus cloud with a strong rain shaft, sending forks of lightning to the ground, and pea to grape-sized hail bouncing off the roof with winds gusting to over 30 mph. This spectacular happenstance was triggered by a surge of much cooler air in conjunction with the lifting of air associated with our approaching trough just above those Cumulus tops yesterday afternoon. That steepened the lapse rate; spring-loading those Cumulus clouds as it were, allowing tops to rise and still be that bit warmer than the surrounding air and stay buoyant as they rose. Here are a couple of TUS balloon soundings rendered by the Cowboys of the U of WY:
While cloud fattening and ice was expected late in the day with sprinkles and light showers, the U of AZ mod run based on 5 AM AST data was spectacular yesterday morning in foretelling this larger eruption as that cold air moved over us. But were grape-sized hail stones and LIGHTNING expected? Not only “no”, but “HELL no”.
Here’s your day, reprised below, of which the MOST IMPORTANT part was the first detection of ice, very tough yesterday, but a precursor to the rain that began to fall a few minutes later. You can also reprise your day here thanks to the U of A time lapse films. Watch what happens around 5 PM, if you can read the tiny font in the lower left hand corner.
Here is the pictorial of your cloud day below:
12:06 PM. Flatness.3:49 PM. Clouds fattening, no ice visible anywhere yet. Nice cloud street generated upwind of Pusch Ridge, floating over Catalina. Shows wind direction at cloud level is from that direction.4:01 PM. Nice cloud shadows and sun highlights moving along the Cat Mountains, too.4:34 PM. Something’s definitely happening now. Note turret protruding on the left. Clouds evolving into larger masses to the south, the cloud street having broken up. And, those massing clouds are upwind of us. Still, no ice evident.4:35 PM. Ice! I can’t believe it. Its going to rain! Can you find it? This is REALLY tough. 4:37 PM. Close up of ice. A higher top was breaking off to the NE and was converting to ice.
5:07 PM. By this time, ice had formed in cloud clusters all around Catalina, and this beauty erupted upwind.5:22 PM. About to strike with hail, lightning, wind and rain.5:35 PM. While the rain and hail weren’t done yet, it gave this colorful scene reminiscent of summer sunset color except that the sun would be setting WAY over there on the right out of view.5:40 PM. Second thunderstorm with hail in formation upwind of Catalina.
Yesterday was one of those ideal days for us here in Catalina, the kind that draws visitors from all over the country to be together with us. It was also kind of like that space-age, relaxo-elevator music; goes nowhere in particular with a hook or melody, or if there is one, its been eviscerated by sleepy, sedated violin players.
But, going back to yesterday’s weather, you could have taken a nice snooze in the sun yesterday afternoon, with only zephyrs to brush up against you, and with temperatures in the upper 70s, it was perfect for being unconscious for a bit, not having to worry about missing an ice crystal, a patch of virga, or an interesting pattern in middle-level or high clouds that you should write about in your weather diary, or document with a photo.
BTW, tops of the small Cumulus (humilis) were warmer than -10 C (14 F) yesterday, and so not one ice crystal or snowflake fell out of them.
6:52 AM. Residual Altocumulus castellanus from the little rainband that went through the night before last.
2:00 PM, from along Equestrian Trail, these picaresque small to medium Cumulus clouds, hold the ice, with dramatic shadows on the Cat Mountains.
Imagination going dry. I’ve talked about these kinds of days a lot. Will insert cow with cholla ornamentation here as a distraction. Might be best part of blog today.3:44 PM. Cumulus clouds wither to Cu fractus as temperature falls. These days are so clear that it seems the earth ends just over the horizon.
Today’s clouds (should be interesting)
Should see a band of Cirrus and thicker ice cloud, Altostratus, off to the NW horizon by about mid-day. Some Altocumulus likely around, too. That band (you can see it here, courtesy of the U of AZ Department of Weather). should arrive here here during the mid to late afternoon, producing a fair amount of gray. But also there should be thinner portions before the main icy mass gets here. In those thinner portions and leading CIrrus, there could be some some great patterns, like Cirrus uncinus, hooked Cirrus (“Angel’s hair”). Lower Cumulus clouds are likely to form over the mountains during the mid-late afternoon. Could be really pretty overall if you can get out of your windowless office for a moment to take a peak this afternoon.
Freezing level and the critical -10 Centigrade (14 F) level for ice formation in clouds here in AZ will be lowering especially during the evening and overnight hours, and should lead to ice formation/virga as the clouds fill in later in the day and overnight. This means a chance for measurable rain here. Noticed just now that yesterday morning’s U of AZ mod (available after about 10 AM) did have a few hundredths in Catalina overnight tonight. You can also see this progression of clouds, more or less, in the U of AZ model output from that yesterday morning’s run here1.
Will write more about later happenings in November when the prior forecasted rain in the models returns; its gone for now!
The End.
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1The 11 PM AST model run from the U of AZ is not yet completed, so to HELL with it! Hahaha, just kidding, but must move on to other chores, like digitizing old research flight videos from the University of Washington’s Cloud and Aerosol Research Group I was once a part of but now its over, plane gone, group gone. Life changes, not always for the better, I can see that now. I liked flying in clouds, hearing the graupel hit against the bubble where I had my head, standing on a little stool in the back. BTW, here is what the bubble looks like. I like to look at it even now and remember all the great cloud friends I got to know and write about.
The aircraft dome that was atop the fuselage of the University of Washington’s research aircraft. RIP. For awhile after retirement, I felt lost as many do. So, I would put this on my head, maybe while doing yard work in Seattle before coming here. It seemed to help the withdrawal I was feeling in those days. Great as a rain hat, too! It really didn’t look that bad.
Here are the surprising totals from the Pima County Alert gauges. Mt. Lemmon received 0.31 inches from last night’s little rain! And most gauges, except the ones in Catalina, got measurable rain. Very nice NWS radar-derived rain graphic here (and below), something that shows we probably got a sprinkle here in Catalina. (Trace detector was not parked outside last night, a huge oversight caused by too much football on TEEVEE.)
Rain totals from 6 PM to just after 4 AM AST last night. Note how rain streamer just missed us to the east.
Some residual clouds are around and likely will provide some nice sunrise shots, but the rain possibility is over for now.
2:27 PM. Altocumulus perlucidus3:49 PM. Altocumulus, getting fatter here, tending toward castellanus and floccus (tiny Cumulus clouds)5:41 PM. Altocumulus castellanus clouds getting bigger yet, pretending not to be doing anything. No virga showing here, but some was beginning to show up on the extreme SW horizon at dark, as clouds began to fill in toward the S through SW. The appearance of virga would mean that the cloud tops were higher and colder than are seen here.
Next chance for rain is late tomorrow afternoon through overnight tomorrow as clouds fill in late in the day. US mods have backed off rain here, while our Canadian friends with their mod still have some (shown here) as they have calculated a deeper trough; more strength and amplitude (more of an extension to the south of us). However, its a marginal situation and the most that can fall here in Catalina in “Rain 2” would be less than a tenth of an inch.
Way ahead….
Some mod runs still have decent storms affecting Arizona in the 9 to 13 day period, 12th and 17th of November, to be specific, from last evening’s 11 PM run. Not good to be too specific at that forecast range as you know.
While waiting for measurable rain to begin piling up in November, let’s look at no rain so far for the current water year which began October 1st:
The observed monthly rainfall is shown by an adjacent column in yellow on the right… (hahaha, trick or treat, there isn’t any yet)
In fact, speaking of piling up, here’s some rain in this forecast from the Canadian GEM model already for the night of November 4th-5th, and, of course, windy on the 4th before the cold front with this barges in. And, I am happy to report that the USA WRF-GFS model is ALSO showing rain during this time, after being rather reluctant until the run from last night at 11 PM AST, seen here. This is lookin’ good now for our first measurable rain in over a month.
Valid at 5 AM AST November 5th. Colored regions in the lower RIGHT panel are those in which the model thinks it has rained during the prior 12 h (overnight, Nov-4-5). You might have to use binoculars to see it.
But wait, there’s more!
Amajor precip episode has shown up in the 11 PM AST WRF-GRS run from last evening! Check out these renderings from that model run from a site I like, IPS MeteoStar:
Valid for Thursday, November 14th at 11 PM AST. Colored regions indicate where rain should have fallen in the prior 12 h. Note heavier blob over us, indicated by darker green! Valid for 11 AM November 15th. Precip for the prior 12 h ending at this time shown by colored regions. Note bull’s eye in this area (likely associated with mountains around here). So, the mod thinks it could be raining over a 12-24 h period.
In the past we have seen numerous examples of “fantasy rain” produced for us here, often involving decaying tropical storms, that turned out to be completely bogus in this time range, that beyond 8-9 days. Its pretty normal for goofy things to show up in these models beyond that time. Just too much chaos going on and using measurements with their inevitable errors, even if fairly slight ones, not to mention that we don’t really have all the answers to how the atmosphere works.
So, what do we do? We deliberately input errors into a few model runs at the very beginning and see what happens, how crazy the key contours and isobars get. “Pretty cool, huh?”, as Bill Nye the science guy might say if he were writing this. Where they remain pretty steady, that’s where a prediction, even one ten or more days out, is going to be very reliable. Here’s is a sample of one of those crazy results from NOAA:
Valid at 5 PM November 10th
The plot above indicates that there is a very strong signal for a big trough and storms along the West Coast 10 days out. The red lines show that there is a strong signal for the jet stream from the subtropics to be a bit south of us.
The main point here is to point out that while the DAY OF THE RAIN on those forecast maps might change in the models, there are still going to be a number of days where troughs and fronts threaten to bring rain yo Catalina over the next two weeks, and one’s likely to make it as a rainy one.
Thinking now, having a rain bias (“truth-in-packaging” note here), that November’s rain will be near or above normal.
Today’s clouds
Look for a few Cirrus and maybe Altocumulus to appear late in the day with the likelihood of a nice sunset shot.
