Mr. Cloud Maven person doesn’t have to tell you, the advanced Cloud Maven Juniors, where he gets such an outrageously distant forecast that most meteorologists are afraid to make; it originates with clustered lines on something we call the “ensembles”, plots representing the greatest advance in computing and weather forecasting since the Intel 486 chip could be had at 386 prices. In case you don’t believe me again…..
Here’s what I am talkin’ ’bout, the “ensembles” or fondly, “spaghetti plots” for 5 PM AST, the 27th of December, two weeks from now:
The red lines are about where the middle and southern edges of the core of the jet stream is, so, its going to be way south of us, “way” being at least a few hundred miles in its average position by then. That means RAIN here! “Whey” is something else, we don’t what; you should make that clear if you’re pronouncing this exact forecast to someone.
We ignore immediate weather and the possibility of rain on the 16th and again on the 18th ; the TV men and women of weather always have that well-covered.
Looks to be shaping up to be a very good spring wildflower season I’d say. Tell your friends.
The End, except for some recent cloud photos:
From a few days ago, little fluff-fluff cloud on Samaniego Ridge.Be thankful we live in Catalina. Here the TUS urban plume exits TUS borne on SE winds toward Continental Ranch and points W and N. Rarely affects Catalina. Sometimes this urban plume is referred to as the Mark Albright smog plume, named after a well-known U of WA meteorologist who accidentally bought a house over there.December 11th. A band of Cirrus spissatus with almost regular virga trails graced the evening sky.
Finally, also from December 11th, this beauty:
Altocumulus castellanus with heavy virga trails. As a cloud maven, you would estimate cloud top temperatures are less than -20°C, and probably closer to -30°C.
As readers know, we like to jump out ahead, sometimes exceeding professional standards:
“Right or wrong, you heard it here first!”
The totality of evidence, which isn’t all that strong is in our beloved spaghetti plots, ones that have misled us a coupla times this winter…
Valid at 5 PM AST April 8th. These outputs based on global data from last evening at 5 PM AST. Note how the cold blue lines dip into Arizona! So, a big trough is guaranteed about on April 8th, maybe one with enough amplitude to produce a significant rain here in the Sutherland Heights.
Toot, toot, drip, drip. Rain fell on Catalina, Arizona, for the third day in a row, bringing our three day total, at least in Sutherland Heights, Catalina, to 2.18 inches, and over NINE inches at Ms. Mt. Lemmon, subject to quality control later.
Here’s a nice map, courtesy of the Pima County ALERT network, whom I haven’t actually asked to post this but you can go here and see it in the original:
The three day totals for the Valentine’s Day starting storm of February 14th, of course, through the 17th, 4 AM to 4 AM AST. The map has been enhanced with a total over that time period from Sutherland Heights for comparison.
Yesterday’s clouds
No photos, still suffering from WP or godaddy hosting chokehold. Even text takes seconds to appear! Worse than dial up. The above jpeg, just 1.4 mb, took several minutes to upload!
The weather way ahead and soap-boxing the erroneous, “warm temperatures” expression
While the NOAA ensembles let us (me) down in mid-January when it appeared that troughs would dominate in late January through early Feb (it wasn’t even close to that interpretation, and the first time I’ve seen those crazy plots do so badly, will go with them now and present a couple that strongly suggest the drought pattern has been decimated for Arizona and the Southwest; no more weeks of no rain or rain threats, with ridiculously warm days (note, not days with “warm temperatures”, a temperature is a unit of measurement, not a thing that can be cold or warm—-got it? Its the AIR that’s warm or cold, or a day, a month. What if, when a high pressure sat on Arizona, that I said we had really “dense millibars today”, to make a comparison showing how WRONG it is to say, “warm temperatures.” Its HIGH temperatures or LOW temperatures, etc. Tell your friends….
OK, will go through that bit more of uploading misery with these stupefying spaghetti factory plots. Inspect them and be happy if you like unsettled weather, storms threatening or actually occurring every few days. The first one is a week from nows, then ten days from now, and the last one two weeks from now. Exult over the troughulent regime we’re now in! Yay!
Note how the red and blue lines dip southward over the whole southwest US. That dip represents the location where upper air troughs will be occurring at this time. The red lines are more or less the periphery of the jet stream on the warm or tropical side, and the blue lines nearer the heart and cold side of the jet stream.
This “ensemble” approach, where tiny errors are deliberately input into the model data as the computer run begins is deemed one of the great advances in forecasting, this due to more powerful computers that can crunch so much global data so fast. There are always errors in the data, and we can’t measure the atmosphere over the whole globe in an instant, and this is a way of determing what the errors might do to the forecast. Heck, we don’t even know what the real errors are. So we input some and see what happens.
The greater the effect errors have, the more spread out and chaotic the patterns are. When the red and blue lines stay close together, it indicates that at least, tiny errors, don’t have much effect. Normally, after ten to 15 days, the lines are kind of a mess, with only general patterns discernible. (Sure is annoying typing and waiting seconds to see what it is you’ve typed!)
In last evening’s global data runs, the red lines in our domain stay pretty bunched up, indicating a strong indication of troughing over these next two weeks, even out to 15 days! So, cloud maven person is pretty excited thinking that maybe a wildflower or two can now pop up, and our spring greening will go forth.
Just yesterday on a dog walk to the Sutherland Wash, tiny plants were bursting forth from the ground. What a miracle that is. (The wash had no water in it.)
Blue, as in the 5520 meter height contour line as produced by a single run of the many NOAA GFS model re-runs with those little “perturbations” of the starting data. Below, our only hope for rain here in Catalina is if the model run with a 552 decameter height contour over eastern Pacific across southern California (see arrow) verifies. Its an outlier, a rogue, a voice in the wilderness, etc.
From the NOAA spaghetti factory based on the global data taken and perturbed at 5 PM AST last evening. The thin blue line to which the arrow points, would be a major, rain/snow producing trough. But since its an outlier from the other blue lines, representing the heart of the jet stream, its very unlikely to happen, even if it is produced by an actual model run for this date and time.
Some background and diversionary writing in excess; skip if busy
Now that we have more powerful computers, we can run the same model over and over again with very slightly different starting data and then see how the results diverge from one another in the days ahead. In the first few days to week of the model run, the various outputs are virtually the same because the starting conditions are tweaked so very slightly. This is chaos in action! And it makes sense because we measure everything perfectly in the atmosphere at the same instant. So, little errors abound in our starting data anyway.
Think of E. N. Lorenz, “Dr. Chaos”! In fact, he thought our existing atmosphere could shift into a pattern resulting in an ice age without any external forcing (oh, like an interstellar dust cloud coming by for a few thousand years, the sun dimming, etc.)
Pretty amazing thought when you think about it, which you just have.
Nobody really thinks that today, but he threw it out on the table in his seminole (haha) paper, “The Intransitive Atmosphere” back in 1967. He also wrote about that kind of thing in the 1968 American Meteorological Society Monograph, “The Causes of Climatic Change“, papers by 22 of the leading climate authorities of that time. (Based on a 1965 conference at the National Center for Atmospheric Research, located in “Potville”, CO (aka, Boulder-haha. But, they really do love their marijuana in Boulder…).
Strangely believe it, in a further diversion from current weather and a mea culpa downstream that maybe you won’t get to with a lot boring writing before it: not one paper in that AMS Monograph was about the climate effects of CO2! Talk about being asleep at the wheel! Wow.
Well, OK, you can’t blame them too much.
The earth’s temperature was slipping downward in those days, and while it was well-known that the effect of CO2 was to cause warming, it didn’t seem to be having enough effect to counter the cooling, and we were only just getting obs of CO2 from Mauna Loa. Sure, its kind of an embarrassing chapter of science, so your not gonna hear much about it from scientists; the monograph above is almost never cited, or course. We like to avoid mentioning embarrassing chapters.
I could name some others, in my specialty, like those cloud seeding experiments at Climax, CO, in the 1960s which looked so good, so complete, and fooled the National Academy of Sciences because it was really all “smoke and mirrors.” Or those in Israel in the 1960s and 1970s that fooled everyone for a long time, too, but, upon further review, were also “smoke and mirrors.” Yes, that’s right, there was a “consensus” of scientific opinion about the results of each of those cloud seeding experiments that for a time was wrong, as, to beat a dead horse, happened in the early 1970s concerning the prospect of “global cooling;” the preponderance of scientific thought was that an ice age was ahead (as indicated by a climate change conference at Brown University in 1972, the results of which were summarized in Weather and Climate Modification, 1974, Wiley-Interscience publishers, W. N. Hess, Ed. Hell, the earth was cooling, so it made sense at that time!
Pretty amazing when you think about it, which you just have.
We know better now. CMP, like most everybody else, is predicting warming dead ahead, only how much is in question.
Here, we address embarrassing chapters head on, if anyone is still reading, which I hope they are not. Check it out.
About 13 days ago, the NOAA spaghetti ensemble factory showed a result that strongly “IMI” (in my interpretation) indicated a vast weather change beginning at the end of January. Sure, it was WAY out beyond what we consider to be a reliable forecast window, and unprofessional to make a forecast that far in advance, that is, much beyond a week, but the signal, the bunching of lines was so great, I went for it anyway. I got excited and brought to your attention that a likely drought-interrupting weather change was to occur in 12-15 days from then, troughs would occupy the entire Southwest beginning at the end of January into the first week of February.
Its not gonna happen.
Cloud maven person was too confident in his interpretation of spaghetti back then, that a trough positioned in the SW was virtually in cement; it had to happen. I was so excited and so wrong, got carried away, like I did with Sharon so many decades ago, thinking we were surely going to be a couple. I was rongno then, too. Arthur Rongno…. Oh, well, we learn and sort of move on.
Oh, there could still be a major trough toward the 5-6th of February, but as the title imputes, we’re down to a single blue, a rogue contour produced by one of the many model runs repeating forecasts last evening with those little errors in starting conditions. the Lorenz model runs. 🙁 🙁 :{
Check this out. Unbelievable, really, though it is kind of what our ensembles have been telling us would happen. These outputs of jet stream location shown below are but 6 h apart, and that’s what makes this comparison so remarkable; they are so drastically different (check how the orange colors have moved around, and then say, “Oh, my gosh!!”):
The question now is which one is right?
The answer, of course, is NEITHER ONE!
They’re both a little crazy because exact forecast maps like this for 300 h (13-15 days) can never be relied on exactly.
But, here’s where we fall back on our ensembles (spaghetti plots) to help us figure out which one is CLOSER to the truth; that’s the best we can do. Sometimes those plots aren’t helpful; there’s too much noise in the pattern around the world, so the spaghetti plots don’t converge to a pattern in which you can have confidence in.
So, here’s the ensemble (spaghetti) plot from last evening’s global data where the model computer model is started with tiny errors, ones that make no difference in the first few days of the model run, but then due to those, the repeated runs with slightly different errors start diverging, sometimes ending up looking like a ball of yarn. Its where these model runs produce the same result that we have confidence in a forecast as far out 10-15 days. In the plot below, the constricted contours in east Asia and across most of the Pacific, represents high confidence in where the jet stream will be in 14 days. The left turn to AK and a big hump off the West Coast is also almost surely the pattern that will be in place as well, as is the dive in the jet into the Plains States. Thus, a pattern of warm and wet in Alaska, and cold east of the Rockies is a VERY good bet at the time of this plot.
How about us?
The plot below is tilting toward a trough here, which would mean rain/snow chances along with below average temperatures. This, by the way, is the OPPOSITE of what the ACTUAL model runs have been telling us would happen for the past two to three days (as was the subject of a somewhat comprehensible blogulation just yesterday here). Sadly, though, the ensembles were off in their strong suggestion of a trough here, starting in late January and continuing into early February. So, we’ve lost a little of the precip expected when that pattern faded.
What about panel 2 above, which suggests a major storm for Arizona?
Its almost certainly a bogus outlier; its not supported. Its not impossible, but you wouldn’t make a forecast on that pattern. Most likely our trough pattern will, from another interpretation of the ensembles, be farther inland from the coast, which would mean colder and not as much precip as would be suggested in panel 2. But its pretty certain that its not going to be hot and dry, a computer solution that’s been roundly rejected from this keyboard all along.
No clouds; no photos.
How about a pilot weather joke instead? Fits with the models joking us around I think:
Yesterday, after I finally saw the model run based on global data from 5 AM AST for Feb 6th, CMP (the writer) was gloating that bit. The troughy, cold spaghetti for AZ, that which had been excitedly written about yesterday, was being confirmed; the interpretation right on, it seemed. Why even look at more model outputs until later January, I thought.
Then, just now in the pre-dawn darkness, I examined the computer outputs from last night’s 5 PM AST global data, also for Feb 6th, 5 PM AST. That is, global data crunched just 12 h later than the first panel I was gloating over, feeling really great about.
But, a completely, ghastly different weather regime had popped out!
How could this be? We don’t know. Relatively small changes would be expected, but the model outputs should gravitate back to where spaghetti placed the high and lows aloft. But this change was ridiculous, and must be rejected.
Some people, like neighbor and big professor “emeritius” of meteorology at Colo State U, Bill Cotton, refer to such differences as “delta model”. “Hence”, if that word is still used, today’s title.
(For snowbirds who have just moved to Arizona, the maps below have been annotated to show where you are relative to the rest of the US).
Yikes!
The first regime is cold, maybe some snow down in Catalina at some point about this time (early Feb), whilst the 2nd regime for the same time is suggests warm conditions, and definitely dry; no rain nowhere.
CMP (the writer) spoke of a high probability, based on ensemble spaghetti, of cold and lots of precip chances here in Catalinaland beginning at the end of January through the first week of February So, what’s up with that, this dichotomy?
Moving on to a new topic, let us look at last evening’s sunset rather than ponder what happened to the weather computer model, that is, which panel above is likely correct1:
6:09 PM. Cirrus uncinus and other forms of Cirrus provided a beautiful sunset highlight.
The End.
—————————————
1The first regime above, the troughy, cold one, is strongly supported by ensemble outputs whose crazy-looking output plots are fondly referred to as “spaghetti”. The second panel served up from just last night’s 5 PM AST global data is not.
Have not looked at last night’s ensembles, but will ignore the bottom run anyway; will not panic as weaker elements might, that is, change my overall interpretation of troughy conditions in late Jan, early Feb., that is#2, reverse course now, predict drought and warmth for early Feb. , that is#3, “yo-yo”, as forecasters describe reversing course, confuse the public, lose credibility, where are my pills?
……yet. :}.
Still, “egad re this delta model”, as Bill likes to say. Its astounding! A total joke! The later one to be totally and completely rejected!
In no way did I expect to see what’s in the bottom panel, which is now above here! Trying to not panic real hard. (more kidding)
Still, how can there be an outlier of that magnitude as we see from last night? Must be a real bad error somewhere (maybe 2 kts of wind, 1.5 deg in temperature, wind direction, 5 decameters in geopotential height, etc), not an itty-bitty error as ensembles start with. Maybe Russian2 hackers did something, the North Koreans, or the Chinese? Just kidding
with weather noise and pseudo-paranoia, your Catalina cloud-maven of sorts.
Speaking of Russia, my great-grandparents emigrated from the Ukraine, here’s the cover of my latest book, published a few years ago. Well, its not my book per sé, but all the cloud photos in it are mine! How great izzat?
A book about flying. I asked that my contributions be dedicated to A. M. Borovikov, the great Russian cloud physicist. Did a lot of airborne stuff in the 1950s and 60s. The cover photo above I took while in KWAJEX in 1999, a tropical cloud study featuring several research aircraft centered at Kwajalein Atoll, Marshall Islands. Of note, seeing a monument to the bravery of the Japanese soldiers (fair enough), and seeing a Japanese military plane land there during our six weeks. Gorgeous clouds! Kwajalein Atoll is the terminus of missle launches from Vandenberg. Alerts on TEEVEE tell you when they’re coming in. Unlike in Hawaii where people panic when missles are coming in, folks on Kwajalein go out to “see the show.”
0.22 inches was, indeed. how much rain fell in the form of drops from Nimbostratus clouds yesterday as a modest little rain band generated by a rapidly moving trough swept through during the afternoon. Regional precip values can be found here. Our local area got the most, up to about a quarter of an inch, as often happens in marginal storms.
Yesterday’s storm marked the beginning of the new, more normal weather regime for southern Arizona, as has been blabbed about here in recent weeks. No more week after week of droughty weather with temperature far above normal, the kind of weather that has marked this whole fall and winter so far! I. e., “Thank you very much, a snowbird might say, but get the hell out!”, the rest of us might conjure up, thinking about the needs of our desert’s wildlife and vegetation.
Indications are now that below normal temperatures and above normal precip are ahead for us and all of Arizona in late Jan and early February.
The evidence for these claims?
Below, the stunning, jaw-dropping evidence for this seemingly outlandish assertion in the form of an ensemble (spaghetti) plot generated by NOAA last night. I have followed these charts for almost ten years now, and I cannot remember when such a strong signal (clustering of flow lines) 15 days out has occurred before in our region.
So, excessively excited this morning when I saw it! Its been annotated with excitement text.
This troughy pattern begins to take place on January 30th. Until then, a strong but dry cold front with a lot of wind comes by in a few days, on the 25-26th.
Valid at 5 PM AST, February 4th. You can pretty much count on a trough hereabouts in two weeks. Since the blue lines, the colder portion of the jet stream, do not dip down this way so much, our troughiness likely would be in the form of something we call a “cutoff low.” A full latitude trough extending from the “blue jet” up there in Canada, instead of a “cut off”, would be excessively cold. We probably don’t want that anyway.
Yesterday’s clouds
The whole interesting, if excessively gray story is shown below:
7:24 AM. It was breezy already, and with Cirrus underlain by Altocumulus lenticularis clouds in the lee of the Catalina Mountains, you knew that a storm day was ahead without turning on your favorite TEEVEE weatherman.8:53 AM. With Cirrus and Altocumulus spreading rapidly from the SSW, lenticulars downstream from the mountains, the wind gusting to 25-35 mph, you knew a great gray cloud day was in store!11:32 AM. Before long, an entire sheet of Stratocumulus spread over the sky, making you sure that rain would fall.12:50 PM. First drops begin to fall on Sutherland Heights. That layer of Stratocumulus appeared to be deepening as it approached from the SSW to where the tops were getting just cold enough upwind of us to produce ice and snow that melted into those sparse drops. Not enough ice /snow formed to hide the bases, though, in virga.1:26 PM. Snow begins to fall on the Lemmon.2:04 PM. Lower Stratocumulus clouds begin to show up below the original deck that overran us.
3:16 PM. Pretty and dramatic. Stratocumulus piling up over and upwind of our Catalina Mountains/Pusch Ridge.3:19 PM. Oh, so pretty.3:27 PM. Crazy, I know, but I thought these scenes were so pretty!3:28 PM. As that rain band approached there were some nice lighting highlights.3:40 PM. Here comes that rain band across Oro Valley/Marana.4:19 PM. A truly great scene for a desert; mountains partially obscured in precipitation.4:19 PM. Nimbostratus. Its hard to get a better photo of rainy Nimbostratus than this. Drops coming off the roof, NOT raindrops, can also be seen. This was at the peak of the rain, too! Very exciting.5:54 PM. Sunset Stratocumulus, hold the ice. Yet, that Stratocumulus was cold, way below freezing.
The weather way ahead
The title sums up where we are now. Will we go have more rain? Oh, yeah. But not right away, as you already know.
A swatch of Altocumulus perlucidus translucidus (sorry, that’s the way we talk around here) passed over Catalina early yesterday afternoon, each “unit” nearly perfectly evenly spaced with its fellow cloud element creating a brief period of cloud awe for those Catalinans (or is it, “Catalina-ites”? “Catalinians”? Who knows, who cares?). Here it is, in case you work indoors and missed it. It was truly a fabulous sighting!
1:16 PM.1:16 PM. Starting to take too many pictures of the same thing!1:16 PM.1:16 PM, of course. So pretty.
The afternoon was marked by a melange1 of middle clouds:
1:52 PM. Altocumulus opacus with a Cirrostratus above.3:11 PM. Some equestrians on horses (haha) went by the house. Sometimes we focus too much on just clouds here, and so we offer the reader who visits here an occasional relief from cloud fatigue.3:12 PM. Those equestrians were being shaded by a Altcumulus perlucidus and by an overcast of Cirrostratus. If you look real hard, you can see a faint halo. The Cirrostratus was thickening upwind as an upper level wave approached and was increasing the amount of rising air aloft over us. The Altocumulus clouds also thickened toward sunset. See below.5:07 PM. Heavy Altocumulus approached from the SW, keeping the sun from under-lighting the Altocumulus as it went down, so no flaming sunset last night. The Cirrostratus overcast continues. All in all, a fine day for Catalinians!
The weather just ahead
The local TEEVEE met men are, of course, pounding out the good news rain is just ahead for Catalina. Looks like, oh, 100% chance to CMP (Cloud Maven Person) starting after midnight Tuesday to Wednesday. How much?
This is a potent, but fast moving trough. Maybe will have only 2-4 h of rain with the passage of the cold front and its rainband. But, coming from the sub-tropics, should have a appreciable rain band with it.
I would expect rainrates to reach “moderate” as the heart of the band goes by for a coupla hours, anyway. Moderate rain is defined by the NWS as 0.1 to 0.3 inches per hour. So, only two hours of moderate rain should be at LEAST 0.2 inches, and most likely more.
We’re thinking here that there’s a 90% chance of more than 0.15 inches, and a 90% chance of less than 0.70 inches. So, averaging those two leads to a best estimate in CMP’s opinion of 0.425 inches! Wow. Nice.
Now, I will look at the U of AZ nested model and see what it thinks. Kind of game we play here, seeing how a seat of the pants forecast, made over a coupla minutes, measures up to a computer model with billions if not trillions of calculations:
Cumulative rainfall ending at 3 PM AST Wednesday afternoon. Catalina is in the GREEN, indicating that the Beowulf Supercluster thinks we’ll have over half an inch (Ms Mt. Lemmon, over an inch!) I am so happy!
The weather way ahead
After the nice rain just ahead, we have to get through the week-long dry spell before we move into a new stormy regime. First, a spaghetti depiction of the ridge after our nice storm:
Valid at 5 PM on the 14th. Huge ridge has stacked up along the West Coast, making it look like the drought will continue ad nauseum. You’ll be discouraged when the middle of January comes around (though by then, everyone will know this is a straw ridge, will collapse in almost hours from this time from the outputs made in real time then.)
Here’s what’s been exciting for a few days now, and below, from last evening’s global model output:
Let’s see what the actual and very latest model run from IPS Meteostar has for us:
From the 11 PM AST last evening global model output this big boy. Unlike so many prior troughs that were bogus this winter at this time ahead (two weeks), this one has spaghetti support and will be real!!! And, it won’t be the only one!!! I’m shouting again!!!
How much these coming rains can benefit our spring wildflower bloom and spring grasses I don’t know, but I sure hope they can resuscitate what otherwise will be a dismal spring.
Expecting a snow event during the “new regime” that takes over after mid-month, too. Be ready!
Yep, unless you were outside yesterday morning, you probably missed the few drops that fell. But fall they did, giving us officially a trace of rain for January! In case you don’t believe me, here is a shot of the incoming shafts of rain. OK, “veils” of rain.
8:22 AM. Rain reaches the ground from thick Altostratus/Altocumulus clouds.
Now, a historical forecasting criteria note after that paragraphical blog title, a criterion that still holds true:
In the 1950s and 1960s, the Los Angeles forecast office used the 564 decameter height on 500 mb weather maps (those made for about 18,000 feet above sea level) to delineate where the rain line was for incoming troughs. North of that, rain fell; south, no rain.
It was remarkable how well that worked.
Don’t know it that height criteria holds here in AZ, probably not, but the 500 wind max seems to be a good discriminator for TUS for rain; under or north of that max seems to be a necessary (though not sufficient) criteria in wintertime. (That wind max does not hold in Cal; rain often falls south of the 500 jet max; only east of the Sierras and coastal ranges does it hold.)
Lately, as winter gets colder, the NOAA spaghetti factory has recently lowered the red line heights to 564 dm in their 500 mb spaghetti plots, you can see that in 5 days from last night’s 00Z run, rain is virtually assured in southern Cal using that criterion, and we hope that rain gets here, too.
Check out where red lines are in the plot below. I’ve helped you to find red lines on this plot by annotating them with an arrow:
Valid at 5 PM AST. See red lines. See red lines move east from California.
But after that trough whooshes by like a Nike logo, in ten days (2nd plot), we’re doomed again to be in the midst of a long warm, dry spell:
Valid on January 14th, at 5 PM AST.
But what about after that next warm, dry spell? The weather way ahead
In a less professional comment than the usual ones posted here, reaching beyond the 10 day forecast limit, that domain of the models where things that are forecast beyond ten days often go to hell with just the next model run, these spaghetti plots foretell a collapse of that big fat, storm blockin’ ridge after our next warm, dry spell! It collapses into a muddle down, oh, I dunno, way down in subtropics somewhere. Yay! I can feel your happiness as I write this for you!
That ridge collapse means, first of all, that strong storms will blast Cal with needed flooding (well, big rains, anyway), and its likely that those Cal blastin’ storms will reach into all of Arizona providing a much needed hiatus in our drought, that is, will bring appreciable rains right here into Catalina as well. You can see if I have made this up by looking at the whole sequence here, keeping an eye on where those red lines are foretold to be.
So, that’s it, that’s my take on the longer term weather pattern:
“A Change Gonna Come,” as so eloquently sung by the master, Sam Cooke, when that 500 mb criterion was being used in LA, and apropos here because a change is gonna come, not that long from now. (Warning: The historical video scenes with Sam’s heartfelt tune will bring tears I just learned… Everyone should see it. Yep, we’ve been through a lot since he sang that song….)
Will keep you up to date every so often if it looks like my take, cribbed from the spaghetti plots is going to be correct in that drought bustin’ part I’ve described beyond ten days. In the event this “take” goes bad, it will, of course, not mentioned again. May have to fall back on writing about aircraft ice production in supercooled clouds to distract you.
That’s why you come here, to answer important questions like that. After all, those precipitating clouds could have been Nimbostratus, Stratocumulus opacus praecipitatio, Cumulonimbus capillatus incus flammagenitus, or even just “plain” Cumulonimbus capillatus (no anvil), and possibly, Stratus opacus nebulosos praecipitatio.
Of course, with no large fires around, we can at once rule out Cumulonimbus capillatus incus flammagenitus….(the new name for clouds on top of fires, formerly referred to by the more accessible terms, “pyrocumulus” or “pyrocumulonimbus.”
For the curious, and since I broke my camera and don’t have the dozens upon dozens of photos to regale or bore you with, I will reach into the archives for a shot of “flammagenitus” and show you one from the pyromaniacs’ paradise, Brazil!:
Brazil, 1995: Cumulonimbus capillatus flammagenitus. Shot taken by Arthur on flight from, Porto Velho to Maraba. The black at the bottom is mostly smoke. Where it starts to turn a little white is where cloud droplets are forming. Smoky ice is just above the aircraft’s wing and a little behind it. You probably didn’t expect to see a “flammagenitus” here today, but, here it is.
Now, on to more recently viewed clouds, like yesterday’s:
9:16 AM. Stratocumulus praecipitatio line the tops of the Catalina Mountains. What’s “wrong” with this scene? Very shallow clouds are precipitating, ones likely exhibiting, yep, the rare phenomenon in Arizona of “ice multiplication” wherein ice forms in clouds with tops warmer than around -15° C or so in great concentrations (often 10s to 100s per liter.) Here, probably not that high, maybe several per liter of unaccounted for ice. Happens when the cloud droplets are larger than usual–so when you see shallow clouds precipitating, but ones with tops still below freezing, -5° C, say, you can report in your cloud diary that you saw some “ice multiplciation on that day. You would definitely get some accolades for such a report if cloud maven club members were to read it, perhaps, an “Observer of the Week” award. Of course, you get a mountain of extra credit for stating that those crystals falling on side of our mountains (Sam Ridge here), “look like needles and hollow columns” those ice crystals that form at temperatures higher than -10° C (14° F).10:52 AM. The actual cloud that produced this mist-like precipitation has literally “rained itself out.” What’s interesting here for you is that there seems to be no demarcation of the melting level. Hmmmm. Was this all drizzle then that fell out of that cloud, starting at cloud tops noticeably below freezing? It happens, though usually that phase is short lived as ice takes over.10:52 AM. A wider view of this intriguing scene. You can see all the glinting rocks, too, due to a little water on them. So pretty, the highlighting and all.11:08 AM. This shot, not taken out the window whilst driving since that would be crazy, gives a nice profile to those shallow, precipitating clouds. Sure would have liked to fly through them, see what the precip actually was. However, we do know that it was snowing on Ms. Mt. Lemmon, so that implicates the ice phase. If you were up there, you may have seen those needles and hollow columns, of course, mostly in aggregates (snowflakes). And, to trigger the “ice multiplication” process, you may have seen some tiny snowballs falling, too, ones we call graupel or soft hail.The U of AZ balloon sounding for 5 AM AST yesterday morning. May have been valid for those shallower preciping clouds.
Later these scenes were overtaken by a slab of Nimbostratus and steady light rain for a few hours.
A note on the recent southern Cal rain blast
As you know, up ten inches fell in some mountain locations in southern California as a monster low pressure system smashed into the coast near San Francisco1. You might recall, too, that the shift of the jet stream (and thus storm track) into the southern portions of California was well predicted two weeks in advance in those crazy spaghetti plots. You can’t always get much out of those plots except maybe the degree of uncertainty in weather patterns a couple of weeks out, but that was a rare case in which the signal far upstream for something strong barging into southern Cal also strong. And, of course, we are experiencing the residual of that storm, also as was indicated in those plots (“…the weather change around the 18th.”
Presently, a another sequence of extremely heavy rain is in the pipeline for central and northern California starting today, which will take a few days for it to come to an end.
Following a break, what was intriguing in the model outputs, and a little scary was that it appeared that yet another scoop of tropical air was going to jet across the Pacific under another blocking high in the Arctic and Gulf of Alaska into California. Take a look at this prog:
Valid Sunday, March 4th, at 5 PM AST.
Here’s where spaghetti can shed some real light:
From last night’s global data, this output for March 4th at 5 PM with writing on it.
So while it is still possible that some model runs will indicate a blast from the sub-tropics affecting Cal, they can be pretty much waived off as outliers (not impossible “solutions” but rather unlikely ones. Breath easier Califs! At least after the current onslaught ends.
BTW, can you see what kind of weather is indicated in this plot for the SW and old Arizony?
Cold; temperatures below normal, precip likely at times.
The End.
——————————– 1The low pressure center that passed over San Francisco yesterday was not as deep (988 millibars) as the notorious “Frankenstormmaggedon” of 2010 which barged into Frisco with a 979 millibar center. You may recall, too, that spaghetti had strongly suggested a “Frankenstormaggedon”, as it was later called, also more than ten days in advance. Recall, too, if you can recall, that 2009-10 was an El Niño winter with this kind of thing pretty much anticipated.
For history buffs, I reprise that January 2010 storm as seen on our national weather map. You may recall that, if there’s anything left in that noggin up there, that Catalina experience no less than THREE inches of rain as this system went by, taking a couple of days:
11 AM AST, January 21st, 2010.Valid at 2 PM AST, February 17th. Junior.
Right out of Computer Shopper magazine, too! You can’t find deals like this today, that’s for sure.
