Didn’t Bob Dylan write a song about this? “Rainy days, #12 and 35”, or something like that? Well, we’re writing about rainy days, too, but #s 4 and 17.
Error-laden model runs1 I really like footnotes; creates a sense of erudition where there is none), #s 4 and #17, based on yesterday’s 00 Z (5 PM AST) global data, have the best chance of a substantial storms here in Arizona in the December 20-22nd window. So, we hope that those errors in those runs are correct!
Here they are, amongst the other error-laden runs below. Novella-sized explanatory caption, an innovation first seen here, included:
Valid Friday, December 20th at 5 AM AST. The key contour at 500 mb that I had gone to some trouble to annotate, is the 558 decameter one, usually in the heart of the jet stream at 500 mb. If that contour really swings offshore as in 4 and 17, we are in for some great precip, rain with a good chance of it turning to snow as it the situation progresses after Friday morning, the 20th. But you can see that there are a bunch of those error-laden contours (oval) that are along the West Coast and dip down this way into the bottom of the “trough bowl” in the SW overall. Those would bring precip here, too, though due to the drier trajectory of the air, not as much as #s 4 and 17, which we could refer to, if we named them, “rainy day women (or men), #s 4 and 17”, maybe write a song about how bad they could be….
So, if I haven’t said that already, were going to see the actual model run based on the data as best we know that data (remember, it always contains some errors we can’t pin down), will flop around some in where the 558 contour and heart of the Jet Stream end up over these next few days. This is because the errors grow in time the farther away the predicted map is. So, as we get closer to December 20th, we’ll see the model runs “converge” more closely to the one that’s going to verify. We want #s 4 and 17, but, you can see that they are “outlier” model runs (“outlaws” to add a more western motif to this attempt to explain something. Hope like mad, too, because 4 and 17 would be real drought denting storms, and phenomenal for the wildflower bloom ahead (probably, too, for those who ski on top of Ms. Mt. Lemmon).
How about those middle and high clouds yesterday?
There weren’t any. Hahahaha (on me, who said there would be some).
Well, except for that tiny streamer of Cirrus on the S horizon at sunset, some afternoon Cu also on the S horizon (Cu not mentioned yesterday, but there they were). Here is the only shot from yesterday of any interest because the Cu I saw down there was about ten times larger than I imagined a Cu could be yesterday. All in all, it was a pretty gaffey cloud day. First, a documentation of no clouds….
4:26 PM. Day concludes with no clouds. An example, looking SE.
4:27 PM. Looking S about as far as you can possibly see. Note Cu congestus down there. Was an remarkable site for a December day.
Today’s clouds and weather
Those distant Cumulus clouds yesterday were a preview. More Cumulus, Cumulus congestus later on in the afternoon, ice likely to form in the larger ones as weak “cold upper low” goes by, freezing level comes down some. Ice in clouds means virga and rain showers as the Cumulus congestus transition to small Cumulonimbus clouds in the area. Lightning possible in the region. Apparently, its too dry aloft for even mid-level clouds3; they’ll be off to the SE-S of us if we can see them at all. All in all, a pretty cloud day is in hand even without patterned middle clouds.
The End.
—————————— 1Lorenz2 or spaghetti or Global Ensemble Forecast System plots (GEFS—hahahah, should be GAFFES because they have so many errors in them!)
2I have made this name up because I think he (E. N. Lorenz) deserves that these plots, representing an attempt to resolve the weather chaos out there, be named after him. Are you listening world? (Well, of course not. I’m just a cloud maven person here in little Catalina and nobody reads what I write anyway…)
3This deduction from our great U of AZ model that forecasts soundings over us from which you can see what it is store for moisture profiles overhead.
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.
“A historic 7-days of weather” or “An historic 7-days of weather”? Check this grammar site out, in case you were wondering, like this English language buffoon was. There must be simpler languages I can learn…
Check out the national records that fell during the past seven days here. You can view them here, but its best if you go to the original site and poke around. Pretty amazing week. You should feel pretty bad if you didn’t set some kind of record where you are, somehow got left out. Also, maybe I should check for locusts and big earthquakes…in case things are coming to an end overall. Just kidding, astrocatastrophists, thermageddonites (warm and cold ones1), etc.
Interestingly, he sez, this was all foreseen in the models more than a week out, mentioned here, and the reliability of that severe weather pattern buttressed by those crazy looking NOAA generated “spaghetti-Lorenz” plots that Mr. Cloud Maven person often displays that evaluate the degree of chaos out there by running models over and over with DELIBERATE little errors. Imagine, how bad things would be if we did that, added deliberate errors to everything we did every day that added on top of the inadvertent ones: “I think I will err today by putting too much electricity into my computer, modify plug to fit in a 220 receptacle, plug it in, see if it runs faster.” In a way, those crazy plots are doing that to see how much things change with errors we know about (since the obs contain errors that we don’t know about). So running the models with little errors is to see how robust a forecast is.
The weather ahead
Enviro Can GEM mod is seeing more rain in AZ late Wednesday into Thursday than our WRF-GFS, so I like it more than our own and it would behoove2 you to check it out for yourself to see if I am lying again. Still, its a slight upper level storm that drifts in from the southwest from off Baja. There will be great middle and high clouds no matter what happens. Rain extreme amounts are wide, zero (USA WRF-GFS) to a tenth of an inch here in Catalina by Thursday evening. Would fall from mostly mid-level clouds showing virga first. Best estimate, therefore: 0.05 inches. Oh, well, SOMETHING is in the works. You can see it spinning around out there off Baja here from the University of Washington Huskies Weather Department.
The weather way ahead
Check this out, you Lorenz plot expert. I went crazy when I saw this, really points to a great chance for a substantial storm on the 20-22nd. Need more rain for those spring flowers!
Valid at 5 PM, December 20th.
Above is an example of a strong signal for a big, cold trough 10 days out, something like we in the West have just experienced, though probably not “historically cold” not quite as cold as the present situtation all over, and along with that, another great chance for a good rain here in Catalina. As we say, CMJs, “Tell your friends.” Your favorite weather person should be all over this by now, going “deep”, you might say, with his/her audience giving them a brain thump.
Not real happy, though, about another round of low (properly, not “cold”) temperatures.
Your clouds today?
Cirrus-ee ones, maybe heading into thick ice clouds we call Altostratus. Get camera ready for great sunrises and sunsets over the next couple of days. Could be extra spectacular.
The End, of the excitement for today.
——————————– 1During the global cooling hysteria (hahaha, sort of) during the late 1960s and early 1970s, my Department Chairman at San Jose State, Dr. Albert Miller, who smoked a lot and died when he was 54 years old, suggested to me that we put soot on the growing Arctic ice pack to melt it off and increase the amount of sunlight absorbed at the ground to ward off global cooling. If the earth’s snow cover go too big, it was posited at that time, it might cascade into a complete glaciation of the earth due to feedbacks caused by too much reflected sunlight by the increasing snow cover.
2Interesting that an expression seeming to pertain to perissodactylas (hooved critters, i. e,. ungulate mammals) is used in conjunction with advising people to do something. “Behooved”? Could be, but isn’t, put on hooves? Try not to think about this all day so that the work you have to do suffers.
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. :}
Well, that cloud WAS “creeping” toward us after suddenly appearing on Pusch Ridge at dawn… Looky here:
7:14 AM. It thinks we’re not looking.7:25 AM. In only three minutes, a spurt toward Cartalina, hugging the mountains where its safe.7:44 AM. I wasn’t watching for awhile, and suddenly, there it was across from me!8:00 AM. By this time it was just sitting, pretending it was something innocuous, but I knew better.1:44 PM. By afternoon, it was gone… Or is it? You see, creepy Stratus fractus is afraid of the sun, twist and writhes in a death throe, evaporating right before your eyes when the sun comes out, or the weak light from the sun, as yesterday, warms the air up a little. Stratus fractus is truly cold blooded and only strong light will make it go away! The end. Below, some apropos music and commentary…
———–
With Halloween only 10 and half months away, I thought I would “get in the mood” and make up a little creepy-ness for the little kids who read this blog. Hi, kids! Hope you didn’t get too scared reading this. “Uncle Artie” is sorry if you did get scared.
What you saw in that sequence of Stratus fractus movement is also demonstrative of what often happens to smog layers funneling out of the Tucson area toward Mark Albright’s house in Continental Ranch, Marana. Here’s an example of creepy morning smog (smoke and other aerosol junk), partitioned to the lowest layers near the ground by a radiation inversion, a temperature reversal that develops at night that results in a temperature rise as you go up. In the afternoons, after the sun has done its work for awhile, the temperature DECLINES as you go up and the smog molecules are dispersed over greater and greater depths. Got it?
7:32 AM, December 2, 2013. Maybe you remember this morning. Smog stays down there until the sun comes up, and then slowly creepy-creeps toward Catalina and our foothills as the wind changes direction and comes toward us in the late morning and afternoon. Happens during stagnant weather patterns, not much going on. Fortunately, the heating by the sun disperses this goop into a greater depth so the smog seems less obtrusive, less visible, though its still there. BTW, the second arrow pretty much point’s to Mark’s winter home in Continental Ranch. Mark is a research meteorologist/climatologist at the University of Washington who got his feelings hurt when he corrected exaggerations of snowpack losses in the Cascade Mountains of the Pacific Northwest and people in his own department got mad at him for correcting those claims; happened back in 2005 or so. But, of course, it still goes on. Mark and his colleagues were proved right in the ensuing years of mountainous snows in the Cascades. Of course, a hundred years from now, well, that might be another story. Tune in later, maybe around 2050 to 2100. It is interesting that when me and Peter Hobbs was correcting cloud seeding claims found in the peer-reviewed literature, ones made by people in OTHER universities, the people in MY department loved me for doing so!
Now, where was I after that big caption….?
Oh, yeah, the weather on deck
Sunday marathoners, achtung!
Looking more like a dry day now on Marathon Day, Sunday, though a cold front will have gone by just before it starts. Looks like measurable precip will be partitioned to the north of Oracle on Sunday, but it will likely be cloudy with Stratocumulus clouds as the day starts, but those should gradually disperse into scattered to broken Cumulus clouds with virga by mid-day, some of those deeper Cu could produce a cold one; i. e., a sprinkle.
Jet core (at 500 mb, 18,000 feet or so) is well north of TUS as Sunday starts, and its really hard to get precip here until the core passes, which on Sunday will be later in the day. But then, the cold front has long gone, and the tendency for precip with the jet core has diminished (subsiding air behind the front is moving in then) to just scattered deeper Cumulus clouds having some ice-forming potential. Deeper clouds are stymied on the right side of the jet (looking downwind) overall in the Southwest in the wintertime by warmer air aloft and stable layers, the kind that produce lenticular clouds.
Below, what”m trying to say in words, is shown in this 500 mb forecast from IPS Meteostar with the wind velocities on it:
Winds at about 18,000 feet above sea level forecast for Sunday morning at 5 AM AST. No rain is also predicted by this latest WRF-GFS model run on Sunday in the TUS area.
Since this is an analysis from a model output, one inherently containing error, there is that inherent bit of uncertainty. So, you, as a weatherfolkperson, imagine what can go the best (the most rainful error), and the worst, and make outlier predictions. Potential rain here in Catalina on Sunday: max, a tenth (everything goes right); bottom, zero (or trace), in this case, as predicted by this model.
Way ahead
I will leave you with this. I think its looking more promising for storms later in the month. I think you’ll see what I mean:
Gauge 15 1 3 6 24 Name Location ID# minutes hour hours hours hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.00 0.04 0.08 0.08 0.43 Golder Ranch Horseshoe Bend Road in Saddlebrooke 1020 0.00 0.00 0.04 0.08 0.43 Oracle Ranger Stati approximately 0.5 mile southwest of Oracle 1040 0.04 0.08 0.12 0.12 0.47 Dodge Tank Edwin Road 1.3 miles east of Lago Del Oro Parkway 1050 0.04 0.04 0.08 0.08 0.47 Cherry Spring approximately 1.5 miles west of Charouleau Gap 1060 0.00 0.04 0.08 0.16 0.71 Pig Spring approximately 1.1 miles northeast of Charouleau Gap 1070 0.00 0.00 0.08 0.08 0.35 Cargodera Canyon northeast corner of Catalina State Park 1080 0.00 0.04 0.08 0.12 0.51 CDO @ Rancho Solano Cañada Del Oro Wash northeast of Saddlebrooke 1100 0.00 0.04 0.04 0.08 0.28 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Road
Santa Catalina Mountains 1030 0.00 0.00 0.00 0.04 0.20 Oracle Ridge Oracle Ridge, approximately 1.5 miles north of Rice Peak 1090 0.00 0.00 0.00 0.00 0.00 Mt. Lemmon Mount Lemmon 1110 0.00 0.04 0.12 0.24 0.71 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 miles south of Coronado Camp 1130 0.00 0.00 0.00 0.00 0.04 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.00 0.00 0.00 0.04 0.24 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.00 0.00 0.00 0.00 0.04 White Tail Catalina Highway 0.8 miles west of Palisade Ranger Station 2280 0.00 0.00 0.00 0.00 0.31 Green Mountain Green Mountain 2290 0.00 0.00 0.00 0.00 0.24 Marshall Gulch Sabino Creek 0.6 miles south southeast of Marshall Gulch
As you can see, a couple of stations in the Catalina Mountains were virtually missed by the storm (ZERO total, for example, at Ms. Mt. Lemmon) or it snowed on those low total precip gauges and the snow has not melted and is sitting in the gauge’s funnel. Select choice number 2. Mountains just becoming visible; looks like snow down to 6,000 foot level.
Didn’t see any precip/virga before dark yesterday, started raining just before 10 PM, nicely, and continued through midnight when it quit. However, the main event, lasting about 6-8 h is supposed to start happening about now, but rain mostly lighting up in TUS. That means we should see some clearing around mid-day, but leaving enough low clouds stacking up around the Catalinas for some nice quilted sun and shadows on those mountains, one of our prettiest sights I think, along with our now snow-capped mountains.
FROPA, or “frontal passage” in weather text speak, occurred late yesterday afternoon. I wonder if you noticed the wind shift and dropping temperatures? However, was a very shallow depth of wind that shifted, and temperature took about 3 h to drop 10 F, (58 F to 48 F) not exactly as sharp a FROPA as was anticipated from this microphone yesterday. Also, a bit unusual, the rain band was displaced far behind the wind shift that occurred around 4:30 PM.
Yesterday’s clouds
I thought yesterday was quite an interesting day for you. Lots of cloud types to log in your weather and cloud diary. Let us begin our retrospective with Sunrise on the Equestrian:
7:05 AM.7:17 AM. Splayed Cirrus display, racing at you at over 100 mph.7:52 AM. Orographic Stratocumulus top the Catalinas, a very good sign that the incoming front will produce rain. Indicates reasonable lower level humidity already in place.9:34 AM. Small Cumulus form over the Oro, Cirrus above. So pretty a sight, I thought.12:17 PM. Micro-snowstorm (Cirrus uncinus) passes past the Catalinas. You can see this cloud from the U of A here in their time lapse movie.12:58 PM. Seattle-style Stratocumulus overcast. Got a little homesick there for a minute.
3:38 PM. Atop horsey Jake now, looking for signs, knowing that front is getting closer. Here those darker, lower line of clouds were atop the windshift that was about to occur, marking the leading edge of the front. This colder air has lifted and chilled the moist air from the southwest to help create that lower base, the sure sign of a wind shift. Looking north toward Saddlebrooke from near The Chutes on the 50-year trail .
toward
4:27 PM. Cloud bases lower significantly as the cooler air rushed in. But look, no precip in spite of the heavy cloud cover. What’s up with that? No ice present in them; cloud tops still too warm in even FROPA area1.Also at 4:27 PM, looking toward weak sun producing the lighting break on the Catalinas. Note haziness, likely due to dust.
Your next storm: due in Sunday morning. Likely just something around a tenth of an inch. Nothing showing up beyond that, but lots of mod fluctuations re storms. I suspect the one that showed up a few days ago for the 20th or so will arise again in some future run. Just a gut feeling since there’s no evidence in the spaghetti plots yet to support that hunch.
The End.
———————————————— 1The TUS balloon sounding yesterday afternoon about the time of the next to last photo. Shows tops WERE warmer than -10 C, in case you didn’t believe me because the clouds looked so dark yesterday afternoon. They were pretty dark because there was a higher ice cloud overcast (Altostratus) and when droplet concentrations are high, clouds are darker on the bottom. We usually have pretty high droplet concentrations here in old Arizony.
Note that the temperature of the air (blue) lines slope upward to the right.
1) I like to refer to songs about weather, though the musical references I’ve used are somewhat dated, as here, a song from 19th Century I think. BTW, tapping on the link above, you’ll see a guy riding a horse AND singing at the same time because he’s so happy, so it really fits the big western life we’re all leading here in old Arizony in the wintertime and seemed apropos. I wouldn’t recommend singing AND riding at the same time, however, unless you know you’re horse reel good. Might get spooked if it was you or me singing and not the cowboy, Gordy MacRae1.
BTW#2, if you watch that entire song link above, you’ll see whole crowds of people getting carried away with the State of OK at the end of it. But…you’ll also notice in that scene that there is a MOUNTAIN on the distant horizon in the background. I don’t think they were in Oklahoma for that song! So, maybe they didn’t really like Oklahoma as much as they claim in song…. Now, where was I?
Man, the clouds are going to be spectacular today, zipping along like a dragster on nitro! Expecting some real great lenticular clouds, those hover ones, downstream of the Cat Mountains, too. Lots of wind, as well, to add to the drama with a Big _Cold Front (B_CF) getting closer during the day, then passing us during the evening-overnight with some rain by morning. Likely to be a 10-20 degree F drop in temperature within an hour or less, as this real “bad boy” cold front and wind shift go by. Ely, NV saw a 56 degree drop in temperatures in 24h. We Need more rain; always. Cold? Not so sure about that. All in all, a “beautiful” day2 coming up.
How much rain here in old Catalina?
We’re on the edge of the jet stream up there, and you know what that means, on the edge of the precip, too. So, if you’re telling your friends how much rain you expect, and as a CMJ, they will expect you to comment on it, you’d best not go overboard and say, “a half an inch between tonight and Friday morning”; play it down some.
On the plus side, this is a storm type (flow pattern type, more westerly up there) that we Catalinans get MORE rain than surrounding areas, other than the mountains. So, on the edge means a low rain prediction; but the flow pattern suggests pushing a little on the greatest amount possible for an edge storm. Here’s the range I would tell you to say to neighbors:
Bottom (since it might miss), 0.08 inches (the “8” for faux accuracy); top, 0.50 inches (yep, has a high potential due to the storm type; that is, the angle of the winds impinging overhead on our mountains). Average of these guesses, which likely is the more accurate guess-amount, 0.26 inches.
Later we will compare the U of AZ supermicro Beowulf Cluster model prediction, one that takes our best model’s overall prediction for Arizona, the one WRF-GFS, and then breaks it down into our local areas better, like here and on the Catalina Mountains, because it uses much more detailed terrain. (Not available yet here at 4:45 AM–to Hell with it then!) ((Still not available as of 6:24 AM. It is finished..publishing now.))
There’s another cold blast on the heels of this one. Hits on the 8th. Poor TUS marathoners… ‘Nuf said.
The weather way ahead
2) With the upcoming storm and cold well in hand, that is, well described by our excited met men and women, both at the NWS and on TEEVEE, where in the latter case they make a LOT of money, really, its incredible how much (well, maybe not in TUS, but LA? Oh, my) Let’s see, where was I? Oh, yeah, I thought I would look WAY ahead, two weeks, which in weather model terms is like an astrologer looking through a telescope at the giant star, Betelgeus, its that far away in model prediction terms.
Still, I REALLY think you need to see this forecast even though its so far away because its pretty giant, too, in weather terms. If you’re too lazy to click on “this”, I have gifted you with the highlights below, highlights that might be the best forecast maps I have ever seen (again). Yes, to quote the song, “Everything’s (weather-wise) going my way.” ( “My way”? To Catalina, Arizona.)
Drum roll……
Well, there they are. I hope you’re happy now. Its quite an orgasmic sequence from a weather standpoint.
Why? There’s about THIRTY-SIX hours of rain in our area are foretold from these maps, 14-15 days from now! That last one has heavy rain throughout Arizona! BTW, I’ve posted them in sizes that are proportional to their credibility, thumbnails.
Now, since I’ve been learning you up on spaghetti, I’ll let you decide whether its a Big_Outlier (BfO). Take a look here and at where the”blue” lines are. They would have to be clustering down around Rocky Point-Puerto Penasco for this forecast to have any serious credibility.
Yesterday’s clouds
Cirrus ones. As always with our deep blue skies now days, so pretty up there. A few shots:
7:32 AM. Bunches of Cirrus spissatus.
8:01 AM. The ever-present, rarely seen Cirrus castellanus (bubble Cirrus lower center).
8:02 AM. Cirrus fibratus (long, more or less straight trails, at least from this overhead view).
5:26 PM. Subtle sunset color in Cirrus and in a distant Altostratus layer (deep ice cloud).
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1Not wearing a helmut, either, which is also a bad example besides singing while riding a horse.
2Words can mean different things to different people, and here, “beautiful”, as in the title, may not be the “beautiful” day you were expecting to be described.
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.
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.
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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.
“Call the uh oh squad1.” I wasn’t going to blog today, was going to take a few hours off, enjoy the TG week by cleaning up the place all day before guests arrive tomorrow afternoon, not really enjoying anything at all, really, but rather, having gone into a new mental frame of mind, a higher one, in which you notice things that you didn’t notice before that are now “wrong”: the clutter, the dirt, the shabby windows, the dog hair. You now see them all!
But then when I saw the newest spaghetti plot, heart started pounding, not just because I love spaghetti, real spaghetti and these plots, but also because of what I saw in the new plot: The “old outlaw”, that old prog, the “old outlier” of yore, the one I showed yesterday with its severe storms for AZ and Catalina, and then went on and on about it likely being an “outlier” model run, and really, exerting a LOT of mental energy to try to explain why those severe storms were UNLIKELY to happen here in southern Arizona.
But that forecast of strong storms is, in fact, becoming the mode in the model! Outlier a la mode; a weather dessert of sorts for us in precip-challenged old Arizony.
Compare these plots below carefully for the SAME verification time, the first, the very one I showed yesterday, and the second, hot off the NOAA spaghetti site from last night:
Valid at 5 PM AST, December 7th.Valid for the SAME time as the first plot above, but generated 24 hours later. I think you’ll see what I mean by, “uh-oh.”
What’s so different?
That trough in the mid-Pacific is now foretold to be much deeper (extends farther to the south; compare), a key for our own much deeper, more southward-penetrating trough downstream here in the West. Those blue lines (that cold 552 height contour at 500 mb) are now bunched farther south in the new spaghetti plot for both locations, in mid-Pac, and in the West, with many fewer of them to the north (open, blackish regions).
Not much jet stream amplitude (north and south meanderings) upstream?
Probably not much downstream, either. Look, too, at how the yellow lines have amplified here between the two plots! So a firming up of high amplitude upstream translates to a better chance of troughs extruding southward into old AZ downstream.
But why did things change?
After all, NOAA puts in tiny errors at the outset of model runs to help show us what the most likely outcomes are, so we don’t expect to see “outliers” start to dominate progs as they have started to do since two days ago. But they have. Dunno for sure why things changed, but one would guess some real errors out there must have been large, larger than the ones NOAA starts with to see how the model runs change (disperse) from the one they put online for us to see.
Valid at 5 PM AST, December 5th. That contour at 500 millybars (about 18,000 feet above sea level) represents the border of the cold interior of the jet stream with really cold air there, aloft and at the ground. The jet core at this level (brown area) is far south of us at this time. Is it raining here? If you have followed this blog your answer, without even needing to look at the precip forecast, is, “Oh, yeah, baby”; probably lots of it, too. I got so excited I misspelled, “Ensanada”! (Let’s see if anyone notices…..) Maybe its a test to see if ANYONE is reading…since I misspelled it twice!
In case you don’t believe me, that is, what I wrote in the caption above about it raining a lot here just judging by the 500 mb configuration, I now present the precip forecast for this period, one I had not seen before writing this sentence, and show it to you.
Rain areas for the 12 h ending in the early morning of December 6th (5AM AST)
Actually, rain begins (in this mod series from IPS Meteo) during the day of December 3rd, as the storm that threatened rain at the close of November, first of December, FINALLY dribbles in from the Pac.
So, this could be quite the weather period for Arizona coming up. Certainly enough cold air and severe storminess is making its way down the coast from AK and points north, that we should be hearing about severe weather, snows in unusual places, blizzards, that kind of thing, before this system gets here. Looks like we’ll have plenty of warning, too, to prepare for an “interesting” spell of weather, hard freezes following the storms, windy periods, maybe another inch of rain over a few days, that kind of thing.
Great pattern for the flowers of spring!
Of course, that far out, its not in the bag for significant rain, but cold air, a hard freeze late in the first week and beyond? That seems to be the MOST confident outcome.
Today? You got yer Altostratus, nice sunrise, just now, and those clouds, thinning to Cirrus, likely augmented by Altocumulus, will likely be here all day–check sat loop here from the Huskies. Enough holes in this cloud sheet, though for a great sunset I think.
