Very happy to post this breaking future news here on February 24th. Close rain call on the 27th, too, as the first of two significant troughs with their low pressure centers march into California, bringing a drought break there of some consequence. Likely an inch or two in the coastal areas south of SFO (“Frisco”; rhymes with Crisco), and maybe even LA area as well with the first storm. That first one continues across Arizona bringing widespread, though light rains the central and northern mountains on Thursday the 27th.
Valid at 5 PM Thursday, the 27th. Upper left panel shows “little brother” trough over Arizona, and most of State covered by a little precip (lower right panel). Big brother on the move offshore of Cal, flow reaching deep into sub-tropics.
Then “Big Brother” hits Cal beginning on the evening of the 28th, gets here late on the first or early on March 2nd. The LA Basin rains in the second one look like they’ll amount to 2-4 inches, and maybe something from a quarter to half an inch here in Catalinaland when it arrives.
Model?
Canadian GEM (General Environmental Model). Sometimes, like their hockey team, it defeats the US models in weather forecasting, and I am riding the fence that it will this time. In the interest of disclosure, the US WRF-GFS model has virtually NO RAIN in Arizona on the 27th (!), whilst the Canadian one has widespread rains (both using global data from 5 PM AST yesterday). So, I reject the US model, one that takes the first storm too far north to affect AZ much. (This has sometimes been a problem for our US models.)
Second storm?
Both models have rain on the 1st-2nd, but the Canadian, much larger amounts in southern California where I grew up and, while having poor grades after puberty and the realization of girls (!) hit, nevertheless had some success playing baseball. Could be nearly a month’s worth of rain in one storm in the LA area, which averages about 3 inches in Feb and March, both, IF the Canadian model verifies. Those kind of amounts upstream would also mean more rain potential for us here, too. But, the fact that they BOTH have rain, is really great to see. One would think that some rain is pretty much in the bag. I hope they put rain barrels out in Cal!
After the storm…
Oh, me, look at this “Lorenz” (the chaos guy) plot:
Valid March 8th, 5 PM AST. Its awful as a graphic to begin with, but when interpreted its even more awful in the kind of weather it implicates for us as we march farther into March: in one word, Hot and Dry! Easterners won’t like it, either, as the severe winter continues back there, Lake Superior might remain frozen over until April! Jet stream is flowing along the red and turquoise lines, so cold air brought southward where lines aim toward the southeast, as over the eastern US.
A pattern like the one above is hard to maintain in March since the climatology of March-May leads to a trough in the western US. So hoping the awful pattern above will give way by mid-March or soon thereafter, as do easterners I would bet. Below, likely fantasy, since its WAY out on the forecast horizon, but this historic forecast (would produce historically cold weather in the East if it did verify, chances probably less than 30% as a wild guess. I just now saw it and it was AMAZING!
Valid March 11th, 5 PM AST. LOOK at that high pressure area and cold air slamming down east of the Rockies and strong low over New England. Good grief! Would be headlines if it happens.
Yesterday’s clouds
9:22 AM. Great example of Altocumulus perlucidus.1:47 PM. Later became blobby with heavy virga; Altocumulus opacus virgae if you really want to know.6:22 PM. Skipping ahead, these formations led to another in a long series of nice sunset shots. Hope you got one.
Total precipitation predicted for Catalina (0.01 to 0.10 inches) ending at 5 AM tomorrow morning. Some to the north fell yesterday afternoon, but it wasn’t that much. Sure, its yesterday’s model crunch based on data that’s almost 24 h old, but its got some rain in it, and glimpsing the incoming cloud mass, now located in western AZ and southern Cal, this looks a little reasonable to even a little low now. thinking now that it will be more than 0.10 inches; might get 0.11 inches here in Catalina. Have dip stick (rain gauge one) ready. A new set of computations is not yet ready, but by the time you crawl out of bed and while I’ve been working, the link above will have new information that might be a little different than what I am looking at here at 4:10 AM AST. But I have to move on now!
So, look for lots of middle clouds (Altocumulus/Altostratus) again today, but likely bases lowering during the day and looking pretty threatening by evening. Check this sounding sequence from the BC and how the dewpoint and temperature lines come together at lower heights during the day today. So lots of clouds to write about in your weather diary today, pretty much like yesterday1.
No rain and lots of warming ahead after this.
Yesterday’s clouds
Perhaps first, before moving on to something as ephemeral as clouds, we should start with something contemplative; an aphorism written by a man who compared humans and their lives to the activities of arachnids. Pretty effective I thought.
Chief Seattle, too, by his very namesake, reminds us of the recent big Superbowl victory, after which 700,000 Chief Seattleites gathered in the streets yesterday to see the parade of players and other festivities, weaving their own distinctive strands of life.
Sanctuary Cove Park, Marana, maybe. Then again, it might be in Tucson. Nobody really knows where these towns start and end.
Day started with an overcast of Altostratus with mammatus/testicularis (which I showed yesterday) that devolved into an Altocumulus overcast most of the rest of the day, example below:
12:45 PM. Altocumulus opacus. No virga evident.
2:52 PM. Thin wisp of vIrga and light snow top Mt. Lemmon (center peak). Hope you logged it. I did and I was about 15 friggin’ miles away. But don’t feel bad. I sometimes miss things myself. You just have to bear down, as we say around here, and be fanatical about it. That’s the strand I want you to weave in this life.3:46 PM. Altocumulus lenticulars form under an Altocumulus perlucidus layer. View from Sanctuary Cove Park, very nice little loop walk there.
4:14 PM. More isolated examples of Altocumulus lenticularis near the Tucson Mountains.
Seen in Sanctuary Cover Park, inappropriately blooming wildflowers. This MIGHT be a purple “brown-plumed wire lettuce”, best match I could find in Wildflowers of Arizona by Rick and Nora Bowers. Message sent: global warming hitting hard in AZ this winter so far.
On the other hand, to be fair to the earth, global warming’s on the run in the Great Lakes area. Check this “find” out, courtesy of that big troublemaker and former WA State Climatologist, Mark Albright who enjoys finding discrepancies in fashionable postulations, causing people to think, maybe explain things they weren’t expecting:
The green line is the median ice coverage for the Great Lakes. Good grief, has it been cold around there or what? I guess it all evens out, and for some folks, that’s a problem these days.
The End.
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1I did notice that the big clearing didn’t get here yesterday as early as was thought, that clearing between yesterday’s trough and clouds those in this incoming one today and thought I would hide the discussion of that forecasting error in a footnote. But, maybe the whole point of life is learning from your mistakes, taking them head on. Then at the end, when you’ve finally think you’ve got it all right, you die. Doesn’t seem right.
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.
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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.
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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.
Thought the overall clearing that occurred at around 8 PM yesterday afternoon was going to be much earlier. So kind of disappointed there, as all of us weatherfolk are when things don’t go right. I thought I was going to see some nice small to moderate Cu amid big sunbreaks during the afternoon. Instead, that incoming Altocu-Stratocu deck from a mostly wasted Pac NW storm had more in it than it looked like on the sat images. That’s what passed over and occluded the forecast. Still, there was quite an afternoon clearing at one point, if a brief one….. So, I guess I was partly right after all.
3:15 PM. Giant clearing passes over Oro Valley and Catalina as clouds begin to breakup. (Photo not zoomed or cropped at all in a cheap attempt to exaggerate a clearing?) ((By putting a question mark, I am not actually lying right out.))
On the other hand, I do get to report a trace of rain in the past 24 h today, which is always good. Hope you saw it, too, to put a bright spot on an otherwise dismal day.
That incoming deck that piled on top of the residual Stratocu here that was topping Samaniego Ridge, was cold enough to produce virga, and some it fell into the clouds below which allowed it to reach the ground rather than dry up.
Also, some of those lower clouds built upward into that higher deck and developed ice, one produced quite a shaft briefly on the Catalinas. That was the surprise of the day, since it appeared to be too stable for that kind of development.
Mods had no rain around here, too, so they’re a little red-faced, as well.
Here are a few other shots from your cloud day:
8:51 AM. This is a common cloud scene that we have here when moist air is being lifted up as it approaches the Catalinas and moves upward in the slot between those mountains and the Tortolitas. The back edge, shown here, is moving toward you, but either never gets here, or takes a lot longer than it should. The reason is that cloud is forming on the back edge. Sometimes when this happens and you see a big clearing that you think will get to you and it doesn’t, its called a “sucker hole.”
10:57 AM. Here, with Big Blue, I was thinking that the clouds were breaking up, and it was going to be nice, scattered Cumulus, day, and the forecast I made early yesterday morning would turn out to be one of the great ones of our time. Middle level clouds rolled over the top of the lower Cumulus and put the kabosh on that! In a way, it was like that big meltdown in the last two minutes by the Washington State Cougars in their bowl game against the Colorado State Rams yesterday when the “Cougs” were leading by 15 points at that time and thought they had a bowl win with so little time left. But no. Like yesterday’s cloud forecast, the win went into the spin cycle at the drain and then down the tube. The writer worked in the Washington Huskies Weather Department, the Cougs in-state rival, but during bowl season the proper rooting etiquette for fhose teams in your league, the Pac 12.1:31 PM. Surprise of the day. A real shaft on the Catalinas! This was the last thing I expected to see yesterday, you, too. I’m sure. Such a shaft indicates that the top of this cloud got higher (likely just a few thousand feet) than any other tops yesterday, mounding above the tops of the higher layer of Stratocumulus clouds.
2:43 PM. A prototypical shot for pretty much the whole day, one in a Seattle motif; scattered to broken coverage in lower Cumulus and Stratocumulus, with another layer of Stratocumulus on top of the lower clouds.
Sun was able to sun behind the backedge of that Sc cloud deck and produced some spectacular lighting on Sam Ridge.
5:08 PM.5:21 PM. “Cow and sunset”; $1200.
The weather WAY ahead, that is, after the long dry spell now starting…
Still looking at storms passing through here as December winds down and during the first week of January, likely with cold, possibly exceptional cold, in the West. “Stay tuned”, of course.
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.
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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.
“Cards” in title referring to computer models, not some kind of goofy fortune telling thing, though, in fact, the models can be kind of goofy, too.
Also by talking about the exciting weather ahead here in Catalina (how many inches will it pile up?), I wanted to deflect attention from error. No rain here in Catland yesterday, as thought likely a couple of days ago (thanks to Enviro Can’s GEM model), though a couple of light showers and even a thunderstorm were close by. There was even a lightning strike from the cell shown below according to the National Lightning Detection Network, one that’s off limits for the tax payers who paid for it. (Must go through private weather providers or work at a university to see the NLDN directly, quite an outrage, as was the case in the early years of Doppler radar data.)
4 PM AST. Radar and satellite IR image from IPS MeteoStar. Arrow points to Cumulonimbus cloud that briefly erupted to the SE of us.
First of all, the long foretold and then bailed on Altocumulus castellanus (and floccus) showed up yesterday morning:
11:09 AM. Altocumulus floccus and castellanus. Floccus has a ragged base; cas a flat base, not that it matters that much. From the taken- while-not-driving collection though it looks like it. Professional course, do not attempt.
2:59 PM. Later in the afternoon, scattered Cumulus clouds were aplenty under some remaining Altocumulus, but did not attain the ice-forming level, with a couple of exceptions, which of course, I will have to show.
3:44 PM. Small and moderate Cumulus (humilis and mediocris) over the Catalinas. Can you find the remnant puff of ice from the highest turret formerly in this grouping? That ice puff up there tells you that one of these rained on someone earlier. Hope you logged it in your clouds and weather diary…
Same photo as above except with annotation and s… like that. I don’t cuss but it sounded funny to write that, detracting just that bit from erudition; stepping out of character for humor. I laughed anyway. Maybe this blog is just for me anyway. That’s what my brother says.
4:40 PM. Dramatic scenes like this on the Catalinas closed out our dry day.
5:19 PM. Fading clouds and drier air move in from the southwest. All threat of rain is gone, but not of a great sunset.
What’s that about white stuff?
Here’s the latest 500 millybar map (flow around 18,000 feet above sea level):
Valid at 5 AM AST, Friday, December 20th, rendered by IPS MeteoStar. Those bowl games in the SW are going to be SO COLD! Poor guys.
Big U-turn in jet stream shown over AZ and all the way to Canada! On the east side of the U-turn are clouds and precipitation and sh… like that. (hahahaha, to continue an out of character theme for a second for humorous purposes…) In the middle of the U-turn are the lowest freezing levels, on this map, low enough in AZ for snow here has either already occurred, or is on the doorstep or already here. On the backside of the U-turn, where the wind is blowing out of the north, the air is mostly subsiding, drying out, clearing off, allowing huge amounts of infrared heat to escape from the earth’s surface into space.
Here’s something else… See how much stronger the wind at this level is over CA, OR, and WA than in the eastern part of the U-turn? That means the U-turn itself is going to push farther S as time goes on, a mechanical thing. This would be a VERY cold episode for us, hard freeze variety, when the clouds and precip clear off.
While the amount of precip here has varied as the exact configuration and placement of the jet has varied in model run to model run, the OVERALL pattern of very cold air getting here has remained in place. Be ready!
Note, too, in the map above that the strongest winds at this level are WELL south of us, and so its already preciped here. Now I will look and see when the precip starts with this gargantuan trough and record cold (in part of the West) pattern first takes hold: OK, looks like the night of the 19th-20th, starting out as rain, changing to snow as storm ends, IMO.
Terribly cold weather will impact the whole West, and punish the northern Rockies and Plains States again. You’ll be reading/hearing about this one during the through the runup to Christmas, so similar to the blast of cold air that broke so many low temperature records last week. Will be tough on travelers. Not so happy about that prospect.
BTW, just to make a point about those crazy NOAA spaghetti factory plots: they have been pointing confidently, as readers of this blog will know, for more than ten days or so, to another pretty extreme weather event here and throughout the West, and that’s where they come in as an important tool for weather forecasters, when a strong signal shows up. Normally, weather forecasts go pretty bad after five days to a week. But “Lorenz”-spaghetti plots can help us see through the fog of middle range forecasting sometimes. That’s why you look at them everyday to see what’s up beyond the first five days or so.
BTW#2, all of this crashing down of the jet stream suddenly into the West after our nice spell of weather, is due to that jumbo storm that erupts in the western Pacific, builds a high pressure ridge ahead of it, and then that causes the mild-mannered jet crossing the coast in British Columbia to go into a southward, buckling rage, dragging record cold air behind it as it does so from northern Canada. That key gigantic eruption in the western Pacific has also been predicted with confidence day after day.
Really going overboard today, got up too early I can see that…. Below, the first the “la-dee-dah” spaghetti plot valid just two days from now:
See how the illustrative contours are piling into BC and northern Washington State? Over us and the WHOLE West, is a big fat ridge. No problems. Toasty weather, here too, for December. Note also, how small the errors are that are deliberately introduced at the beginning of the model test (or “ensemble” runs)! They hardly make any difference in a 48 h forecast (the lines run on top of each other). The giant low in the western Pac has not yet erupted, so there’s not much amplitude to the jet stream, its just pretty much west to east flow, la dee dah.
But look below at the waviness (amplitude) of the flow in the Pacific AFTER the giant low erupts, forming a big ridge downstream!
Valid at 5 PM AST, Thursday, December 18th; pattern caving in. Wrote all over this, got too excited about what’s ahead.
Whew! Quitting here, got a little over worked today about the weather way ahead. Too long to proof, too…. But HELL, its the internet; don’t have to be a great writer to be on the internet2!
The End, except for historical culture footnote below.
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1Part of the “British invasion”. If you’re a kid, have your parents explain to you that it was not a military thing to reclaim America except in terms of music. Pop music here wasn’t good enough (Beatles were better than the Beach Boys I guess) in the mid-1960s, and so they came, and they came and they came from that little island nation with their weird hair styles and great hooks and dominated the air waves. Pretty soon, everybody had weird hair styles.
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.
Remember Consumer Reports, “Quotes Without Comment” page? Well, I am lying like anything here1.
Only ONE comment today (I’m lying again), but its about wind today. It will pick up suddenly from the north later this morning or in the early afternoon, and be gusty and cold. We here in Catalina get more of this north wind than, say, TUS, which is blocked from this wind by the Catalina Mountains. A big high is bulging into Utah, a state north of us, that’s why.
Next rain chances, a weak one late Wednesday or Thursday, and a stronger one around the 20-22nd, the latter as spaghetti has been suggesting for some time now.
Your cloud day below in case you were inside watching football television all day:
7:03 AM. Note light rainshowers on north horizon. Only a trace here.9:14 AM. Looks pretty much the same. Hmmm. That’s a comment. When it comes to clouds, I guess I just can’t shut up, even when they’re boring Stratocumulus.9:15 AM. Only a minute later! Yes, a “Concerto in Gray” yesterday, to allude to some music that has not yet been written (perhaps it will be one day by a depressed composer), and I want to make sure you see all of the gray we had. Gray was my favorite color in elementary school! THought you’d like to know that. Man, after a second cup of coffee I am just exploding with interesting information!11:49. Still “Overcast in Stratocumulus”; could be the second movement in “Concerto in Gray.” Signs of break up here.11:50 AM. Some of you are dropping away like Jake the horse. Can’t take it anymore. Well, I demand a million dollars to stop blogging! Note, however, that “Dreamer” the horse is still paying attention, setting a good example.3:26 PM. Skies eventually opened up and our pretty deep blue skies returned amid the small Cumulus and shallow Stratocumulus, a rousing, happy finale to our “Concerto in Gray.”3:58 PM. “Frosty the Lemmon”; could be a popular Christmas song. If you stepped away from football television for even a minute, you might have noticed this interesting look on Ms. Lemmon. This frosty look is almost certainly due to “riming” on the trees, the collection of supercooled cloud drops by the trees in windy clouds that are not snowing much or at all envelope them. The liquid drops hit and freeze and buildup on them, much like airframe icing. Substantial water can be collected by trees on mountains when supercooled clouds envelope them in windy conditions like yesterday. Hope that bit of science wasn’t piling on the boring for you. “Piling on” can be a penalty in football if it happens late, like in this blog. I demand TWO millions dollars to stop blogging!5:20 PM. OK, some ice cream on your plain oatmeal; a pertty sunset, pastel Altocumulus above (gray, of course) Stratocumulus.
The End, at last. You can wake up now, horsey!
———————— 1It comes pretty easily to weather forecasters, but you do have to speak with conviction; a certain degree of authenticity has to be imparted when lying. :}
WHAT a gorgeous day was yesterday! Perfect. No wonder the northlanders come here in their droves now! Its great to see (via the increasingly larger number of out-of-state license plates) all the people that want to be where I am already!
While waiting for the storms and cold air just ahead now, this cloud commentary:
Along with the pretty high and middle clouds was a rarely seen phenomenon, aircraft flying into those “supercooled” Altocumulus droplet clouds were converting them to ice in their wakes. These are similar to contrails, called by me, APIPs, Aircraft Produced Ice Particles. That’s right, your Catalina Cloud Maven person named that phenomenon, though its not a great name since it could apply to usual contrails as well. Modest brain strained hard, but couldn’t come up with anything better. So, given that background, he’s probably going to make a big deal out them when he sees one or two here.
Its rare because the Altocumulus have to be pretty cold, -15 C (5 F) or so and colder1, and at a level where aircraft are flying, usually in a descent or climb pattern to their normal flight altitudes up around the higher Cirrus levels (30-40 kft above sea level and at temperature generally below -35 C). Typically because of climbing or descending, the ice canals, or holes with icy centers, are short and small. Here are a few examples from yesterday, but you really want to look at the U of AZ timelapse movie to see a bunch of them going by in those pretty Altocumulus clouds and mackerel skies we had. Note that as cold as these Altocumulus clouds were, they were not producing ice:
12:21 PM. Ice strip produced earlier by an aircraft that flew through supercooled Altocumulus clouds. Usually these events lead to optical displays like this faint sun dog almost overhead. You have about 10 seconds to see it, but, of course, Mr. Cloud Maven person, on a hike with friends, was waiting for it to happen.
11:21 AM. One of many.12:19 PM.11:50 AM. Note Cirrus-ee part upper right.
And there were other fine sights! Look at this display of Altocumulus perlucidus undulatus, rippled mackerel sky:
11:12 AM.1:19 PM during hike with friends, not just people standing there as I walked by, in case you thought someone who would write like this and take cloud pictures all day might be a recluse and have no real friends. Shown are Bill and George, JoAnn and Vollie, admiring the Cirrostratus shield coming over the horizon. (I do see why you might think that, though.)4:42 PM. Day ended up with a great big halo; haloes are pretty rare here in the kinds of Cirrus clouds we get. More Altocumulus out there, too.
Weathering ahead….
Looks like cold spell will last, once underway, into the middle of the month. SNOW indicated HERE in Catalina-land on the morning of December 11th from a crazy model run based on last evening’s global obs at 5 PM AST yesterday. Here’s what that morning looks like overhead, at 500 millibars:
Valid at 5 AM AST December 11th. Thinking about making snowballs that morning. Also, in appeal to youthful readers, I have texted some here. Astonishingly deep cold air piles into Arizona, Those northlanders will be piling into their jeeps and heading home. Unfortunately, an examination of the reliability via the newly named, “Lorenz plots” from NOAA, show virtually no support for this “solution.” It appears, at least for the moment, dang, as a crazy outlier, likely due to some goofy error (s) WAY upstream somewhere. But, its fun to contemplate snowballs here in Catalina.
BTW, the local weather services all around the SW are already worked up over the coming cold wave and have issued Special Statements, quite fun to read because they reflect the excitement we weather folk are feeling now as we look ahead to wind some rain, and a big frontal passage followed by cold air. After all, the weather’s pretty dull here in SE AZy most days of the year, and by “dull” I mean that not much is happening except for pretty clouds and nice temperatures, a weatherperson’s “dull.”
The End.
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1 Yesterday afternoon’s Tucson balloon sounding which I forgot to look at until now:
Rawinsonde balloon sounding data from Tucson. Balloon launched around 3:30 PM local yesterday; rises at about 1,000 feet a minute.
