A lot of snowbirds head home when the temperature goes above about 85 F (30 C) because they can’t take it like we can, which is what will be happening today and for a couple more days before some thick middle and high clouds move in toward the weekend with their often accompanying blazing sunsets/sunrise to go with the blazing temperatures. So, expect some extra traffic on the roads in the next few days. If this blog was a grammar school playground, I’d be calling them “little crybabies” when I saw them leaving.
But, while the hot regime digs in now, “I want to leave you today with this final thought”1but one in the form of a weather map:
384 h from now, or about two weeks. From last night’s WRF-GOOFUS model run which can’t be trusted this far out.
For credence, and transparent, or “clear water” credibility2, we look to the NOAA spaghetti bowl to see if that map above has any support:
Valid the day before of the map above. I think I can see something here that would support unusual rains in Arizona in later April…. Its my job. Those red lines (contours that reflect where the troughs are), at least kind of dip down in our area. But for real credibility, we those blue contours, not red ones.
The End
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1This phrase is kind of a literary device, a trick really, often used to keep people reading, thinking that the piece is going to end without them investing too much more time. But then it goes on some more.
2Though it would be a good name for a band, its not a strained and awkward allusion to the 60s band (“Creedence”3 CR) that broke up because of all the infighting and never got back together to do legacy tours of all their great hits and make a lot money like the Eagles did when they resolved all of THEIR infighting (almost). I guess Hell hasn’t frozen over for CCR. Too bad. I remember seeing CCR live at the Santa Clara County Fairgrounds, and how the whole audience leaped up in unison and as if by command when they launched into their hit, “Proud Mary” with those big, booming chords we all learned to play on our guitars!
3A common misspelling of the word, “credence.” The band was not known for spelling, but man, to name your band with a misspelled word, wow.
First, it behooves me1 to point out that there remains a considerable amount of uncertainty in the weather WAY ahead. This is demonstrated below by the map from the NOAA spaghetti factory from last evening, one that churned out a LOT of “spaghetti”, perhaps making the point about how chaotic weather is:
Valid at 5 PM, March 26th, two weeks from now. Doesn’t matter where Arizona is; although, although… when I look really close….I think I can see some rain for us. The lines are selected contours of the height of the 500 mb surface, after slight errors have been introduced to the initial state of the forecast model. The actual forecast of those contours is in their somewhere.
Yesterday’s Cirrocu
Late yesterday, a thin moist layer moved in and produced, where the air was lifted that bit more, a little patch of Cirrocumulus, our most delicate cloud.
5:09 PM. Cirrocumulus. No ice apparent, something that would blur the spaces between the tiny cloudlets. Height was about 17 kft above the ground, temperature, -15 C. So delicate!
6:28 PM. Line of Altocumulus enhances sunset. Too thick, elements too large to be Cirrocu, though they were both at the same height yesterday.
I think that covers just about everything.
The End.
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1What an odd expression, to “behoove oneself” in effect, as in becoming a perissodactyla, while doing something you feel you must do as a responsible person. Imagine, before issuing a responsible statement, that it was normal for people to put on hooves, or to wear them when coming out to a news conference to announce something responsible, correct the record, etc. Perhaps, if it wasn’t that bad, you would wear only one hoof…
Valid two weeks from now, Thursday, 5 AM, March 20th. Massive trough, at last, settles into the West for awhile, more in keeping with climo. Keep jackets at the ready. Rain? Dunno yet, but probably on the correct side of 50-50 beginning around the 17th. Changes! Warm and dry for a coupla days, followed by a parade of troughs, quite a few minor ones over the next week or so, before the Big One forms. Above, this is a VERY strong signal in the spaghetti for two weeks out, and so got pretty excited when I saw it, as you are now, too. So, when mid-March arrives, get ready!
Was going to close with this NWS forecast for Catalina (might be updated by the time you link to it), but then saw just now that Saturday, the day a cold, dry trough is over us, it’s predicted to be 76 F here in Catalina, too warm. I would prepare for upper 60s.
Canadian model has even had rain near us at times as this trough goes by on Saturday, but only here in the 11th hour (from yesterday’s 5 PM AST run) has the US model indicated that the core of the trough and rain near us on Saturday, as the Canadian one had for a few days before that. Hmmm…
The fact that any trough is ending up stronger than it was predicted, as the one on Saturday, is a good sign of being close to the bottom (farthest S lattitude) of the “trough bowl”, that location where troughs like to come and visit. So, maybe this is a precursor for us, this unexpected little cool snap on Saturday. Maybe climatology is beginning to work its wonders at last in the West.
Powerful storms begin affecting the interior of the West and Great Basin in 10 days, and that pretty much marks the time when the winds here start to pick up to gusty at times as strong low centers develop to the north of us, and the major jet stream subsides to the south toward us.
It will be the end of the warm winter era for us, too. While cold settles in the West, it will mean very toasty weather back East from time to time, something those folks will greatly enjoy.
———————–Climate issue commentary; skip if you’re happy with the climate as it is now—————————-
As you likely know, much of the upper Midwest had one of its coldest winters ever, and just a few days ago Baltimore (locally, “Ballimore”, as in “Ballimore Orioles”) had its lowest measured temperature EVER in March, 4 F!
“RECORD EVENT REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
0930 AM EST TUE MAR 04 2014
…DAILY AND MONTHLY MINIMUM TEMPERATURE RECORDS SET AT BALTIMORE
MD…
A DAILY RECORD MINIMUM TEMPERATURE OF 4 DEGREES WAS SET AT BALTIMORE MD TODAY…BREAKING THE OLD RECORD OF 5 SET BACK IN 1873.
THE MINIMUM TEMPERATURE OF 4 DEGREES FROM TODAY WAS ALSO THE LOWEST MINUMUM TEMPERATURE RECORDED ON ANY DAY IN MARCH FOR BALTIMORE. THE PREVIOUS RECORD MINIMUM TEMPERATURE FOR MARCH WAS 5 DEGREES ON 4 MARCH 1873.”
(Thanks to Mark Albright for this official statement; emphasis by author)
If you’ve followed some media reports, the exceptional cold of this winter has been attributed to global warming, a hypothesis that has been questioned by climo Big Whigs. However, if it is right (which even lowly C-M doubts), parts of the upper Midwest may become uninhabitable due to cold in a warming world, quite a weather “oxymoron.”
Also, if you’ve been hearing about weather extremes and global warming (AKA, “climate change”) you really should read this by a scientist I admire, Roger Pielke, Jr., at Colorado State Univsersity, his rebuttal to a Whitehouse science adviser’s characterization of his testimony before Congress about weather extremes (they’re not increasing).
What seems to be happening in climate science is the opposite of what our ideals are. Our conglomerate of climate models did not see the present “puzzling” halt to global warming over the past 15 years or so as CO2 concentrations have continued to rise. However, instead of being chastened/humbled by this failure, some climate scientists seem emboldened and only are shouting louder about the danger ahead. Presently we are struggling with a number of hypotheses about why the hiatus has occurred (e.g., drying of the stratosphere which allows more heat to escape the earth, more aerosols in the stratosphere in which incoming sunlight is dimmed some as it was due to the Pinatubo eruption in 1991, ocean take up of extra heat, the Atlantic Meridional Overturning Current slowing down, causing northern hemisphere continents to cool off.)
UPdating at 8:28 AM: This from the “current”issue of Science (Feb 28th) about the Global Warming Hiatus (GWH): It might be due to the cold waters of the eastern Pacific, now reigning year after year almost for the whole time of the “hiatus.” (BTW, you’ve heard of it, haven’t you, that hiatus in rising global temperatures? If not, write to your local media sources about this. Its pretty important.) Science mag is $10 if you want to buy it off the newstand.
What ever the cause of the puzzling hiatus in warming, it was not accounted for in our best models right from the get go, and so, naturally there SHOULD be caution on everyone’s part until we know what happened and can get it right in those many climate models..dammitall! Unless we know what done it, how else can we have confidence that they are going to be very accurate 100 years out????
———————————————end of climate issue/rant module————————–
Here are a couple of nice sunset scenes from March 4th, that same day it was SO COLD in Ballimore, these to help you cool off personally after I got you pretty worked up with climate issues. Hope I didn’t spoil your day, and try not to be mad at work thinking about it.
6:19 PM. Row of Cirrus lenticulars appears below CIrrus/Altostratus layer. I think they were too high to be Altocumulus lenticulars, and dissipated into ice puffs right after this shot.6:31 PM. Cirrus spissatus (thicker parts) with strands from Cirrus uncinus under lit by the sun.
Since the Big Bowl is just ahead, featuring our Seattle Seahawks, a team that played their games right near the University of Washington where I worked, it seemed like a good title, one that ordinary, football-loving peoples could identify with. But, of course, I am talking about “trough bowling” and the inclement weather that goes with them, right here in Arizona, not in New Jersey.
Models are foreseeing a spell of upper level troughs collecting in the SW US in the next week. In the map below from the NOAA “spaghetti factory“, you will see a great example of the best chance for a halfway decent rain in AZ as these several troughs march through, including one today (but too far north). All we get today is clouds, mostly middle and high ones, too high above us to rain on us, then later in the day, lower ones like Stratocumulus, but with tops too warm to form ice crystals, necessary for rain here in old Arizony even though it may look pretty gray at times.
Back to the maps….
In the map below, the red, yellow and gray lines all bulge southward toward the Equator in our area. The wind at this level (500 millybars, around 18,000 feet above sea level) travels along the lines going toward the SE off’n Cal, then bend back to the NE over Baja.
The air tends to sink and dry out in flow going to the SE, but tends to rise and moisten as it bends back to the NE. So, as troughs come and go, with the SW winds ahead of them pass by, there’s a chance for rain each time one goes by.
The third one that passes by, later on Thursday, February 6th, gives us the best chance for widespread rains, as foreseen for AZ by last night’s 5 PM AST model run.
How great would that be?
If you don’t believe me that widespread rains are forecast for AZ, you’ve given up on rain here after weeks of drought, I’ve added a map from last night’s model run. Its OK. I’m a weather forecaster and there’s a certain degree of incredulity, an aura really, that goes along with this occupation. We get used to it, kind of like economic forecasters do.
Valid February 6 at 5 PM AST. I’ve annotated it so you will know where Arizona is. Its shocking to me that I have to keep putting arrows on maps showing where Arizona is to my readers.Valid at 2 PM AST, Friday, February 7th, 2014. The green areas denote where the computer model thinks rain has fallen in the previous THREE hours. There are several maps like this after this one for 2 PM, ones that extend the AZ rain into early on the 8th. Who knows at this point, but maybe half an inch could fall here in Catalinaland. Hoping so.
Mods are grim after this storm passes on the 7th, with the jet stream staying north of us, maybe for the rest of February, and that means chances of rain are nil. No jet, no rain.
Oops, I forgot to show you where Arizona is….here’s that same map again.
Same prog, valid for 2 PM AST, Friday, February 7th, 2014. Recall that this storm has been predicted, more or less, for about two weeks, as has the pattern change.
The first real chance of light rains here is just ahead, that on late on MONDAY! Looks like only a tenth of an incher, though, right now.
BTW, poppies in bloom (!) are being reported by hikers here in the Catalina area. Wonder if this has happened before in January?
Looking ahead to rain and other weather mischief in the days ahead.
I think its pretty plain to see in the NOAA spaghetti plot below that our first rain in January will just about be here in a week. Looking forward to an upcoming pattern change, with two troughs zooming into AZ in the week-to-two-week period.
Valid for 5 PM January 9, 2014. Can you find Arizona here? Hope so.
“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.
————————
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.
“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.
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.
“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.
It doesn’t get better than this if you like wind, rain, snow, piles of it, and newspaper stories about Southwest storms. From IPS MeteoStar, these renderings for December 6-8th from our BEST model, the WRF-GFS, crunched from yesterday morning’s global data taken at 5 AM AST:
Valid for Friday, December 6th at 5 PM AST. The colored regions where the model has calculated that precipitation will fall during the prior 12 h before this. Precip indicated in just about all of Arizona Valid at 5 AM, Saturday, December 7th. Twelve more hours of precip throughout most of Arizona! Valid at 5 PM, Saturday, December 7th, precip center moves to just about over my house/Catalina and environs again as it has so many times in the past. Valid for 5 AM, Sunday, December 8th. Rain area intensifies and grows in size over SE Arizona! I was beside myself with joy when I saw this model output!
Now, after all this excitement, you may wonder why, with several model outputs since yesterday morning at 12 Z (5 AM AST) the writer has not updated these maps. If you have followed this site for any time at all, you know the answer; the subsequent model outputs were not as good. In fact, the last one, from yesterday evening’s 5 PM AST global data, had NO PRECIPITATION at all south of about Winslow. Such an outrageous, even if possibly more accurate model output due to being based later global data, is NOT going to be displayed here! I want you to be uplifted by thoughts of coming storms and rain, spring wildflowers in profusion, not droughty thoughts.
But we have a conundrum: Will it or won’t it rain here in Catallina in the first week in December?
And, of course, you know what happens here. We examine that ball of yarn, those “Lorenz plots”, namely, the spaghetti plots from the NOAA spaghetti factory that puts them out, those plots you’ve come to love, to see if we can tease out the answer to our conundrum; which model run was the outlier, the one likely to be WRONG!
Let us first look at the projected contour map for 500 mb, about 18,000 feet above sea level, or about half way through the entire mass of the atmosphere, which is kind of scary when you think about how low that is:
Valid at 5 PM AST, December 7th. We will compare the 552 height line with those “errorful1” ones on the Lorenz-ball of yarn plots below, and see if a lot of those same height lines show up SOUTH of Tucson, as it does here in this great prog. Fingers crossed…. We need a LOT of those same contours south of us for this NOT to be an outlier, goofy model output.
Here it is:
Valid at 5 PM, December 7th, during height of predicted strong AZ storms shown above. The light blue lines are the errorful, key 552 contour lines. Look, there’s only ONE south of Tucson, very unlike the stormy model output showed above! Most of those bluish 552s are WAY to north, indicating that the stormy Tucson mod run was an outlier, not likely to happen as shown.
———————————-Gigantic explanatory footnote—————————————- 1“Errorful”–if you can imagine it, our government weather service puts little errors in the global measurements that were actually taken, and then runs their computer models over and over again with slightly different combinations of DELIBERATE errors. They do this because we cannot measure the atmosphere accurately over the whole globe at the same instant. There are always measurement errors, but we don’t know what they are.
The stronger a pattern is, the less it is changed in the future even with those tiny errors having been introduced at the beginning of the model run. The more fragile a pattern is, the more chaotic the future prediction of it gets. This means that where patterns are strong, the red and bluish lines are bunched together, and where the model is clueless, the lines are all over the place.
Naturally, in the first few days of a model run, pretty much all of the lines are bunched together, but after awhile, the fragile patterns start to emerge as the lines go crazy. Here in the western US, the plot above indicates, even though its 10 days out, that there is, without doubt, going to be a strong trough, lots of stormy action in the western US. The blue and red lines are RELATIVELY bunched together.
The thing that’s missing for us, is the AMPLITUDE of the pattern, that well-predicted trough with storms in the West does not appear like its going to reach down to Tucson, but rather produce rain and snow in the northern third of the State. On the other hand, its not so far away that further slight changes won’t result in precip here, though not the behemoths indicated in the progs at the start of this blog, which I think was yesterday sometime.
In the cool half of the year, its essential for the core of the jet stream to be over or south of us for rain to get here, and that core is located between the red and blue lines above, so its not so far away. Fingers crossed…
Finally, The End (of the footnote, and everything else)
