Note redundancy in title. A “meteor” is already going down, so you don’t need the word “down.” Hahaha.
They were small drops, some were as small as drizzle-sized (500 microns in diameter or smaller) and too far apart to be called an occurrence of “drizzle”, but they fell throughout Catalina allowing Catalinans to register a trace of rain yesterday, a trace that was not predicted by the best model we have around these parts just hours before the “rain” occurred. It’s not clear what the benefit of a trace of precipitation is, but we are sure some ants and other insects were made quite happy yesterday as a virga from a higher level snowstorm spit out a few drops.
Drops that reach the ground in these kinds of situations are due to melted aggregates or clusters of single snow crystals locked together that most people would call “snowflakes.” Single crystals can never make to the ground on a day like yesterday. And, “yep”, that “fog” you saw drooping down on the Catalinas from time to time yesterday afternoon was due to light snow.
No Catalina, Arizona, rain in US mod forecasts through the next 15 days (!–just horrible) as the US models continue to evaporate rain chances on the 6th-8th. A few days ago the system going by then was supposed to bring a substantial rain to most of Arizona. Now its just a dry trough passage in the model, like at watering trough1 with a hole in the bottom. Phooey.
Oddly, the Canadian model, which first calculated a bust for rain here on the 6th-8th when the US model had lots, now has MORE rain in it near us here in Catalina on the 6th-7th than the lugubrious US model. The US model has NO RAIN whatsoever in the WHOLE State of Arizona ending on the morning of the 7th! How odd is that?
Below is the salubrious Canadian depiction for Arizona rain by the morning of the 7th, a rain that could be good for health of all of us and our desert:
Valid at 5 AM February 7th. The upper level trigger for clouds and rain, a trough, is already past us and in western New Mexico, but the Canadians believe that widespread rain will have occurred in Arizona as it went by during the prior 12 h ! See lower right hand panel green and blue areas; use microscope.
Its interesting how you still can remember with fondness those people who affected your life so much, even if for a short time.
Below, after an important aside, your cloud day picture jumble, one that began with a brief, but memorable sunrise “bloom”, and one that also ended with great sunset color on the Catalinas.
7:23 AM. Sunrise over the Catalinas.3:14 PM. Dog and virga.9:43 AM. A brief clearing of a couple of hours duration led to pretty scenes of Altocumulus floccus trailing virga. 8:21 AM. Altocumulus floccus/castellanus trailing long trails of snow virga trails.
5:57 PM. Color on the Catalinas.4:03 PM. Snow on the Lemmon.
The End.
————————
1Images of watering troughs, in case you’re from out-of-state and a city person and unfamiliar with western culteral expressions and don’t know what a watering trough is.
I’m talking about your clouds and weather day yesterday, and definitely NOT about someone whom I shall call, “Sharon1“, that happened to me 33 years ago and whose birthday was yesterday, Ground Hog Day, a day commemorated by a 1993 movie about a weatherman. Seemed “right”, too, to be a weatherman with a girlfriend whose birthday was on Ground Hog Day. I loved her so much! Was definitely in the first stage of the psychologist’s lab standard, the Passionate Love Scale2 ; euphoric when things were going right, and also a stage characterized by delusional and obsessive thinking. (Haven’t we all been there at some point?) Had a great sense of humor and playfulness about her, too. As it turned out, though, I wasn’t good enough for her. (I really wasn’t; she was a med student and all that; very brainy, so there was quite a mental contrast.)
Oh, yeah, NOW for the clouds yesterday on a cool day which is what I was talking about to being with; high only 55 F here in the “Heights”:
6:06 PM. Altostratus, of course, with slight virga consisting of very light snow. Too thick to be Cirrus. 3:18 PM. Altocumulus perlucidus. What the temperature? In the middle of the photo there’s an ice canal–hoped you logged it in your weather diary. That ice canal was caused by an aircraft passing through a cloud that’s well below freezing. The exact reason for the sudden freezing of drops in that cloud is still being investigated. However, when you see this phenomenon, an ice canal or hole punch cloud, I want you to FIRST think of ME, because our paper on this phenomenon was rejected twice back in the early 1980s before being published, and second, when you see this happen, estimate that the droplet cloud was probably at -20 C (-4 F) or colder. Yes, THAT cold and still composed of droplets! Therefore it produces a buildup of ice on an aircraft when one flies through it, but then the aircraft changes that by converting to ice behind it! How strance is that?. (I deliberately misspelled “strange” to see if anyone has read this far.)
Annotated version. 3:19 PM. Frosty the Lemmon. Good sign of rime icing on those trees up there. You see how frosty they look? Likely because of supercooled cloud droplets hitting the trees and freezing during all the low clouds of the previous day. Very pretty. 2:19 PM. “Angel’s hair”, Cirrus fibratus. The delicateness of those striations are amazing when you think that they are traveling in air moving at around 80 mph up there around 30-odd thousand feet above us.
Below, the predicted total rain in Arizona as this great trough goes by. NIL in Catalina! The map below is a forecast of all the rain areas and their amounts expected by 2 PM AST tomorrow afternoon. Fortunately, it has been, as in basketball, “rejected.” Read details in caption.
Expect a trace to maybe a tenth. No drop will escape my attention!
The End. I hope you’re happy now since I have titillated you with a personal story in a cheap attempt to raise blog ratings. Haven’t broke into the top 10 million blogs yet. But maybe if min is more like “Entertainment Tonight”, I make that breakthrough.
———–
BTW, if you haven’t heard yet: “Seattle Celebrate (sic) SB Win!”, a title and article written by a possible drunken AP writer after the SB, if you’re interested.
————– 1Defintely NOT a picture of “Sharon”, but its how she MIGHT have looked had she been in my Seattle living room with her son, New Year’s Eve, 1981. And, of course, I found someone I loved just as much later…
2Don’t believe me that such a thing exists? Read the first column of SCI CLIPPINGS CAUDATE OVER HEELS IN LOVE 001, no less. Probably goes farther in its discussion of these kinds of things than we really want to know about and how they came to know them…be advised.
Not much to say, so will let others speak after showing you this sunset from last evening:
6:01 PM. Best described, due to thickness and coverage, as Altostratus. Note fine virga underneath. It would be a very, very light snow if you were skimming the bottom here. Crystals? Bullet rosettes, natch! Too cold for anything else that had time to grow big enough to fall out.
————————-on claims module——————————–
About really cold air outbursts as we have had in the East (Great Lakes freezing over, etc.) and global warming…. Let’s see what Mike has to say (gonna be a little technical with a ton of references), but I think you might get SOMETHING out of these.
Check here and here. Awards? Too numerous to mention. And he may be the most disinterested person you will ever meet in the current “climate wars” surrounding the issue of anthropogenic global warming1. I don’t mean by “disinterested” that he is bored with his work (haha) but rather that he refrains from axe grinding, stays aloof from the emotions and partisanship that we see so much of in that domain. HELL, I get mad myself sometimes.
Enjoy, if you can.
————————–
Sorry to say there’s no rain in the computer outputs here for another 15 days. Pattern of warm and dry in the West, cold in the East continues to dominate computer forecasts.
The End.
1Fueled in particular these days by the halt in the rise in the earth’s temperature over the past 15 years or so when it was predicted it would continue rising GRADUALLY by our best computer models.
7:16 AM. Altocumulus castellanus virgae. Has light snow falling out of it in tiny filaments, Aircraft measurements show that those filaments, snow fibers, that are falling out right below the base are only 10 to about 30 yards (meters) wide. “Floccus” would be OK, too. Notice that there are two turrets, one is older, has holes in it on the left, while the younger one on the right side looks more solid, firmer. The younger one has not yet formed a strong virga trail, but will as it ages. These are Cumulus to Cumulonimbus transitions in miniature and in slow motion.
Today’s sunrise of the day
7:20 AM. Altostratus.
About up and down…
That giant low pressure center, so needed by us droughty folks here in the SW, has materialized in the western Pacific, shoving gigantic amounts of heat and clouds poleward (up) toward Alaskans. We like to call them Eddy or Eddys; they keep the poles from getting too cold and the Equator too hot by shoving air around. This low in the western Pacific has forced a big northward bulge in the jet stream up that way where it had previously been pretty much a west to east flow. A region of higher pressure is created aloft when there are injections of warm air into the northern latitudes by storms1.
When air surges northward and builds a region of higher pressures in the jet stream like that, it buckles and turns southward on the downwind side of the high pressure (or ridge) almost immediately. In this case, and lucky for us, the buckle is toward the south over the western US and ultimately down into Mexico, but not too far, we hope.
What goes “up” in latitude must go “down”, more or less.
Surface weather map with satellite imagery for 11 PM AST last night.500 millibar map for 11 PM AST. Ridge pilling up in AK-Bering Sea, about to turn jet southward into the western US.
So, that inconsequential looking area of clouds and low pressure which appears to be jetting across British Columbia and Alberta in the first map, will suddenly begin enhancing and expanding southward, new low pressure centers will form in the Great Basin area. It will get windy here for a time. Very exciting.
I guess what I am trying to say, too, is that old timey weather folk like this writer would look at a map like these above, even without the satellite imagery, and think, “Oh, my”, “Change gonna come“, as Sam Cook so sweetly sang so long ago, a drastic change for the area downstream of the giant low and its heat plume.
Things are out of balance at this “map moment”; weather “Koyannisqatsy“, too much swirling low in the west part of the Pacific and strangely quiet downstream over the US at the SAME latitude as that giant low is reaching down toward out there far to the west of us. “This will not stand”, as someone once said about an invasion of a Middle East country. And the “quiet” in the West won’t stand, either. Balance in latitudes affected by storms is a key proviso of weather, a kind of conservation law2 we used to talk about a lot, and still do in undergraduate courses.
We could go back all the way to the Middle East to see the roots of the storm that blew up in the western Pacific. It was already a strong upper level wave that showed up in the Middle East as the snow situation there was beginning to take place. As a strong upper level feature, it was the trigger for the stupendous low that formed when it exited the Asian continent, found heat and temperature contrast that are the building blocks for strong storms.
The clouds and storm ahead
Models have been wetting it up more and more here, sometimes the US model have no rain at all as the trough and its clouds passed too far to the SOUTH of us. But lately, that US model has been increasing the amount rain here, not taking the low so far south. The Canadian model has had rain here in every run for days, so its been more consistent on this pattern, not taking the low too far south.
Valid at 11 AM Friday from IPS MeteoStar, December 20th. The colored regions are those in which the model has calculated precip over the prior 6 h. Note heavy band over Catalina! (Dried up a lot on the next run at 11 PM AST, though.)
Due to the variable nature of the precip amounts seen by the mods, you have to figure there’s an awfully wide range of amounts that can occur here in Catalina from a tenth of an inch on the bottom, to as much as .75 inches if everything goes really well. U of AZ mod will have more to say about this in the next 48 h.
Of course, as cloud mavens, we’re interested in the sky as well as the storms. Lots of precursor high clouds today again like yesterday, and if the usual trend continues, those clouds will lower some as the day goes on from just Cirrus, Altostratus, sometimes augmented by Altocumulus. These kinds of clouds can lead to some fantastic sunrises and sunsets, so have camera ready. You only have a couple of minutes to capture the peak of the “blooms.”
The End.
————————————–
1Remember, low density air (air filled with warmth and humidity), if deep, leads to a small change in pressure as you go up in the atmosphere, and so by the time you’re at 50,000 feet, you’re in a HIGHer pressure region than those regions where the air is not so warm. How odd. So surges of warm air and clouds from the Tropics build regions of high pressure aloft, and that’s what we’re seeing now.
In case you missed the pretty sights of yesterday:
7:05 AM. Sunrise on the Altocumulus. Two layers are evident.8:42 AM. Kind of blasé except for the rarely-seen-in-AZ (faint) halo. Altocumulus with Cirrostratus above.3:30 PM. Pretty patterns; Altocumulus perlucidus.
4:45 PM. Cirrus fibratus (not hooked or tufted at top) and Altocumulus (droplet clouds at right with darker shading). Lower gray portions beyond Pusch Ridge and extending to the horizon is probably best termed Altostratus.4:56 PM. Nice lighting on Samaniego Ridge.5:21 PM. Your sunset. Nice underlit virga (light snow fallout, likely single ice crystals, not flakes) from patchy ice clouds. Could be termed Cirrus spissatus or Altostratus, if you care. What kind of crystals, you ask or didn’t? Bullet rosettes.
The clouds and weather just ahead
Expect more Altocumulus, Cirrus, and Altostratus today, patchy and gorgeous. Would expect some nice Ac castellanus (one with spires) as an upper level low off Baja starts to move toward us. Some measurable rain likely tomorrow in the area, but probably barely measurable, maybe a tenth at most since it will fall from middle clouds with a lot of dry air underneath them. (Enviro Can mod still sees rain around here tomorrow.)
Middle clouds might get large enough to call the (small) Cumulonimbus clouds, with a slight chance of lightning tomorrow, Thursday, as this low moves up and over us.
So both today and tomorrow will have some great clouds!
WAY ahead; watch out!
After a quiescent period of gorgeous, misleading days, where the temperatures gradually recover to normal values and you’re gloating over the nice weather you’re experiencing by coming to Arizona from Michigan, blammo, the whole thing caves in with strong storms and very cold air heading this way.Yesterday’s 18 Z WRF-GOOFUS model run for 500 millibars (rendered by IPS MeteoStar), was, if you like HEAVY precipitation throughout Arizona, well, truly”orgasmic.” You just cannot have a better map at 500 mb for Arizona than this one from that run. That low center over California, should this verify, would be filled with extremely cold air from the ground on up, cold enough that snow in Catalina would be expected as it goes by. So, there’s even a prospect of a white Christmas holiday season. Imagine.
Valid 264 h from 11 AM AST yesterday morning, or for 11 AM AST, Saturday, beginning of football bowl season, which last until February I think.
Now will this verify exactly like this? Nope, not a chance. But, spaghetti tells us we’re going to be in the Trough Bowl, filled with cold air and passing storms beginning in 8-10 days from now. How much precip and how cold exactly it gets is unknown because these progs will flop around in positioning the troughs that head our way. There will be major troughs passing through, so while the amount of precip is questionable, the cold air intrusion is not. It was just so neat, exciting, mind-blowing to see that such a gargantuan storm has been put on the table for us in that 18 Z run.
Most likely subsequent model runs will take this exact map away, but then put something like it back, until we get much closer to verification day, the 21st. May even shift around on which day is the doozy, too, by a couple of days either side. Still, a really exciting period of weather is ahead.
This may seem odd, but one of the keys to our storms way ahead is the eruption of a huge storm in the western Pacific (and that storm is shown developing in the last day (144 h panel) of the Enviro Can mod.
———–dense reading below————-
That erupting, giant low pressure center will shoot gigantic amounts of warm air from the tropical ocean far to the north ahead of it in the central Pacific. That warm air shooting north, in turn, causes a bugle to the north in the jet stream, a ridge, which deflects the jet toward the north toward the Arctic. As the jet stream does that, there is almost an immediate response downstream from the ridge; the jet stream begins to turn to the south, developing a bigger an bigger bulge, or trough to the south. So, a jet stream running on a straight west to east path across the Pacific can be totally discombobulated when a giant storm at the surface arises and shoots heat in the form of clouds and warm air northward1. In this case, all of this takes place beginning in the Pacific in about 6 days, so that a sudden southward bulge, a buckling of the jet stream, due to that giant low in the western Pacific 8, 000 miles away, happens over the western US. And voila, our big cold and maybe our big storms, too. then.
Summary statement: Begins in 5-6 days in the northern US, then expands southward; goes on and on, like the discussion below, after that. Cloud pics WAY below the “novella” on spag plots.
——————————————-
Our docile weather in the West for the past few months is about to end, as well as for those in the Rockies and Plains States. Wasn’t gonna blog on TG day, but looking at mods, and realized that I am the SAME person that I was as a 6-year old in Reseda, California, on January 10, 1949, that ran up and down Nestle Avenue knocking on doors to tell people it was starting to snow that afternoon (!), I realized that same “gotta tell ya” impulse lives on.
The trigger for THIS “gotta tell ya” is how bad the cold, snow, rain, and wind look for the western half of the US starting in about 5-6 days from now as cold air and storminess works its way south from the Pacific Northwest and Rockies at that time. I am sure you have heard something about this developing pattern already from your favorite media weathercaster, but I’ll try to take it a bit farther out in time, and tell you why I think you can do that in this case.
I haven’t looked at the models per se with the exception of the Enviro Can one, one in which the lasted posted output is at the start of this episode, but rather the excitement for Mr. cloud maven person was triggered by those chaotic looking, “errorful” plots we call spaghetti plots, “Lorenz plots”, if you will, posted by NOAA that tell us how sensitive a pattern is to small errors.
It seemed, too, like there was something to be learned from them, as well demonstrating a high confidence pattern of a severe weather pattern more than a week away. Many forecaster, maybe most, shy away from forecasts beyond a week because we know how often they are faulty. But there are exceptions and this is one coming up.
Valid at 5 PM AST, December 5th. This map shows a high confidence of a mammoth, cold trough at 500 millibars covering most of the US. Its “ginormous” as a friend used to say. You really don’t see anything like it, that is, like that black “quiet” zone extending so far south anywhere in the whole northern hemisphere!
OK, here we go.
Above I have added boxes in this plot to show you where the forecast is highly reliable and in another one, where its not. This is indicated by the bunching of those lines, height contours, the same ones, from many model runs starting with the introduction of slight errors. At first in these plots, with errors being tiny, there is no difference in them in the first day or two. But, as time goes on, the errors have greater impact. A metaphor: when you hit a ball off the tee, the error in the first inch of travel is nil in magnitude. But 5 seconds later? Oh my.
Here, the bunching of lines in most of the US is what got me going. Continuing the metaphor above, after 5 seconds and 300 yards of travel in this case, its analogous to 2 yards from the hole! In other words, the were essentially no effect of errors in the model runs; you slugged that golf ball perfectly.
But what does it mean, in terms of weather? That trough (the curved area where the “high confidence zone” is located, means a tremendous plunge of cold air into the West and Plains States. Don’t need to look at future maps to know this. You all know that a trough is a tongue, a wedge, of DEEP cold air that drags cold air at the surface southward on the west half of it, and drags warm air northward on the east side (in this case, toward the eastern US. The size of this wedge indicates a gigantic area of high pressure from the Arctic will be pushing DEEP into the West and Plains States as this pattern develops in the few days before December 5th.
Once established this pattern lasts for several days, a huge, deep and cold trough dominating weather throughout the US. And where the air masses clash at the ground presents ripe conditions for low centers to spin up, given a trigger aloft, like a traveling, much smaller wave in the jet stream where the lines are bunched.
Below, farther along in the sequence, these plots each one day later than the one above that illustrate how a confident pattern begins to erode. In this case, “uncertainty” in the central and eastern Pacific begins to spread eastward into our confident pattern; the blue lines start to go goofy (highlighted by boxes):
Last, here is the plot for 15 days (360 h) out in which those little errors have had their biggest effect, really done a number (haha) on the forecast confidence game, everything’s pretty unreliable except maybe in eastern Asia and the extreme western Pacific, and along the East Coast.
But, even with all of this chaos below, we can see that the model still thinks a trough (a bend in the contours to the south) will still be present in the mid and western sections of the US. Since we know that weather, once changing into a new pattern likes to stay in that pattern for weeks at a time (with brief interruptions), a reasonable forecast for December would be colder than normal in the Southwest and West overall, and in the central US, while its warmer than normal in the East, particularly the southeast US.
Precip? Always more dicey than temperatures, but CM is going with above normal in the interior of the West and in the Southwest, near normal to above normal here in SE AZ. Remember while reading this, Mr. Cloud Maven person is NOT an expert in long range forecasting, like for a month, and, he likes to see precipitation in the desert, and those wildflowers that follow. (“Truth-in-packaging” clause.)
In a couple of days, the Big Boys at the CPC, that is, the NOAA Climate Prediction Center, will be issuing their temperature and precip forecasts for December. It will be interesting to see what they make of these patterns, combined with other factors like sea surface temperature anomalies and northern hemisphere snow cover.
BTW, with a pattern like the one coming up, snow that falls during the storms is going to remain on the ground for long periods due to the lower than normal temperatures, those that snow cover helps to maintain (strong feedback loop, as we would say).
Your clouds of yesterday
If anyone is still with me, you had your Altostratus, your Altocumulus, and some Cirrus. Here they are:
8:31 AM. Altostratus, an ice cloud consisting of single crystals and snowflakes. Slight falls of snow (virga) can be seen at the bottom, that rumpled look. WAY too high above the ground to reach it, estimating 18 kft here.
3:41 PM. Altocumulus perlucidus (left), opacus center and right where they get solid. These clouds are comprised soley of liquid droplets; no virga is showing for one thing, and the greater detail, sharper edges goes with a droplet cloud composition. Droplets are almost always in far higher concentrations that are ice particles in clouds, thus, they have sharper edges. 5:22 PM. Pretty nice sunset, Altocumulus overhead left; in the distance Altocumulus floccus with heavy, funnel-looking virga fall, and extreme distance, some following Altocumulus castellanus, no virga yet.
5:24 PM. Close up of prior scene. Last row visible on the horizon is a nice little row of Ac castellanus.
I’m trying to keep you busy today. Maybe you’re retired and you don’t know what to do with yourself. Well, today you can look at building precipitation totals in Arizona all day! It will give you something to talk about.
In fact, occupying retirees with searches for precip data is why we have so many different sites that record precipitation. We have a lot of retirees in AZ, low temperature refugees, and we need to keep them occupied and out of trouble.
Imagine how awful it would be if we had ALL of these rainfall amounts in ONE place and you could look at them all immediately, or have a map plot of all these sites and amounts? Imagine just CoCoRahs and Rainlog.org being friends and cooperating together and just having one site for their rainfall collections? It would be like the Berlin Wall coming down, precipitationally speaking. Oh, well, that’s not gonna happen.
Oh, yeah, the Heights of Sutherland here in wonderful Catalina, AZ?
Got 0.17 inches overnight. “Main bang” still ahead, quite a long ways ahead, considering the passing showers we have now. Doesn’t look like the major band will get here until after midnight, then pound on us most of the day tomorrow. This prediction from the Huskies of Washington’s Weather Department model seen here.
So being on the toasty side of the cold front, should be a pleasant, mostly day with dry spells in between showers, and maybe, if the low clouds break a little, with fabulous middle and high cloud patterns associated with the powerful jet stream overhead (winds at Cirrus levels today and tomorrow should be over 100 mph!) Have camera ready.
Range of amounts from this front, a little in the withering stage as it goes by tomorrow, here in The Heights of Catalina, 0.4 to 1.5 inches, median guess 0.95 inches. Just too cellular in nature to be sure you get hit with all that’s possible, so you fudge on the downside some.
HOWEVER, just viewed the accumulated precip from our great U of AZ mod and it shows about 1.5 to 2.5 inches here, with the model run ending at 1 PM tomorrow–with more still falling! Wouldn’t that be fantastic! Certainly we’d have water in the CDO.
Precip totals ending at 1 PM tomorrow!
These mod forecasts do tend toward the high side, but I would be very pleased if more than my highest estimated amount (1.5 inches) fell.
As you will see, rain’s piling up like mad in central AZ just to the west of us. Amounts, according to radar, already well over an inch just for the last few hours according to NWS storm total radar loops from PHX and Yuma. Hah, Yuma! How often does that radar see amounts over an inch in winter?
I suppose we’ll be complaining soon about too much rain….
Yesterday’s clouds
So much was happening skyward yesterday! So much so, its probably best seen through the U of AZ Weather Department’s time lapse movie here. Its really great and shows all the complications of a day where clouds are moving in at different levels, and there are lots of wave clouds (lenticulars) over the Catalinas to marvel at.
6:59 AM. Altocumulus patches and pastel Cirrus announce a new day.
7:06 AM. A few minutes later, Altocumulus perlucidus join the color display.
11:07 AM. Once again, the rarely seen Cirrus castellanus (“Cumulus in a Cirrus) that I seem to notice every week here…
11:44 AM. Hover clouds (Ac len) over the Catalina, Altostratus above.
1:14 PM. Barging in from the south, the next lower layer, Stratocumulus and Cumulus; bases touched Ms. Mt. Lemmon. Sky darkened rapidly and almost eerily right after this.4:22 PM. The occasionally seen Seattle June sky, overcast with threatening clouds that don’t do anything, and with mild temperatures. Tops 0f these clouds were right at the normal ice-forming level here, -10 C (14 F), and by evening, virga and light rain began to fall from them as they deepened up a bit more.
The weather way ahead
More rain as month closes out. If you don’t believe me, a theme here, check this image out:
Valid for 5 AM AST, November 30th. Of course, I’m not going to show you the actual rain map, I want you to go from this as a bonafide Cloud Maven, Jr. (CMJ). I’ve noticed that some of you have not yet ordered your sophisticated “Dri-Fit” TM, “I heart spaghetti” tee shirts… What’s up with that?
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.
———————–
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”.
I was driving down in Tucson yesterday, kind of moping around about all the blogs I had done with little or no interest. You may recall from a blog I did a few months ago I reported to my reader that a business site had evaluated the worth of my blog, and due to the amount of traffic it brought, it was found to be worth $25.
But then as I rounded Campbell and headed northbound from Fort Lowell, I saw this sign exhorting fellow Tucsonians to watch clouds! My mood brightened. Maybe there were a few out there that I had affected after all; a whole cloud watching movement had started! I did see, however, that since the sign maker was wondering whether there were clouds in the sky or not, and there was a lot of Cirrus overhead, I saw that I had more work to do.
This sign seen near Campbell and just north of Fort Lowell yesterday afternoon.
Yesterday’s clouds
9:03 AM. Cirrus fibratus in rolls, undulations, due to waves in the atmosphere associated with the strong jet stream above us.
In case you were asleep, watching Monday night fubball, and NOT watching clouds, here is yesterday’s magnificent sunset as the sun underlit those dense Altostratus clouds that developed from thinner Cirrus ones during the afternoon and evening.
5:44 PM.
Today, more mid-level clouds and with strong winds aloft, we should see some lenticular clouds in the lee of the Catalinas. Videoing them would be a good thing for you to do because you would, in fast playback, be able to see how they keep forming on the upwind side and disappearing on the downwind side while holding their overall position. If the moisture increases, they expand, and if it decreases, they shrink and dry up, something likely to happen later in the day.
While that’s going on, there’ll likely be some Cumulus and Stratocumulus off to the north, and since the air is going to be much colder aloft to the north today, some ice is likely to form in them late in the day in those northern clouds, leading to some virga. Those lower clouds, according to our models, should begin appearing around here, too, in the late afternoon and evening. Alas, measurable rain is very unlikely, and with this, last little threat, October 2013 will go out rainless here in Catalinaland.
Farther ahead…..
More middle and high clouds and great sunrises and sunsets are likely on November 3rd and 4th as a little upper level trough creeps in from the lower latitudes of the Pacific off Mexico. It was once projected by the models to bring rain to here, but now it seems only a sprinkle is possible; most of the tropical moisture shunted to the south and over northern Mexico.
In the longer term, while all “fantasy rain” has disappeared for AZ based on last evening’s 11 PM AST model run, stronger than normal storms are showing up for California later in the first week of November, and with that, we’ll always have the hope that this time, the “fantasy” in that model calculations is no rain shown for here.
