BTW, finally got a “submission” in late yesterday about our neat storm after what was deemed a power outage of some type affecting the hosting service yesterday. After re-reading it, perhaps I had too much time to think about it… Oh, well, onward.
First, from yesterday, a day with occasional sprinkles, dessert:
6:48 PM. Residual Stratocumulus and Altostratus translucidus from a cloudy, unusually cool April day.
The remarkable thing about yesterday, and you might have thought it was fog, was the amount of dust in the air after the rain and after the winds calmed down from those 50-60 mph blasts from yesterday. Well, it was plenty windy in the deserts behind the rainy frontal band and that dust-laden air moved in right after the front went by. At first glance, and since it had rained, I thought it might be fog! But a quick check of my senses and the relative humidity, which needs to be near 100%, showed that it was only around 60%, the measurement that demonstrated it could not POSSIBLY be fog. There you have it. Problem solving for you by C-M.
Here’s an example of that dust:
7:12 AM. The unusual sight of thick dust below Stratocumulus clouds and only hours after a substantial rain.
With cloud tops yesterday only having to reach to 11,000 feet above sea level to surpass the magical -10 C (14 F) temperature level, hardly much above Ms. Lemmon, ice and virga from these clouds was virtually guaranteed. And, if you were watching, there was plenty, including from those clouds we couldn’t really see so well due to dust, ones that produced those several morning and early afternoon sprinkles (“its not drizzle”, a continuing theme here. Only a meteorological ignoramus would call a fall of isolated drops, “drizzle” (or snow and rain mixed together “sleet”). Perhaps I am too strong here, but it is important to get it right since REAL drizzle and sleet (raindrops that freeze on their way down through a shallow cold layer) tell you important things about the clouds and layering of the air overhead. Here are some of yesterday’s clouds as the dust thinned (both due to mixing upward into a greater depth, and due to clearer air moving in):
9:09 AM. The dust remains, but the Stratocu is mostly gone. Twin Peaks still not visible from Catalina.10:13 AM. Dust lifts as Cumulus arise on the Catalina Mountains. Nice view of “Catalina Heights” manufactured home country, too, where C-M lives.12:20 PM. By mid-day, quite a few of the highest tops of the Cumulus-Stratocumulus complexes had likely surpassed the -10 C level, probably much lower, to -15 C or lower temperatures, and scattered virga and snowshowers were aplenty in the afternoon.3:20 PM. By this time cloud tops had descended, weren’t so cold, and those Cumulus and Stratocumulus clouds just kind of sat around not doing much but making pretty shadows on the Catalinas.
By mid-afternoon, most of the deeper clouds with substantial virga were gone. You can see what happened in the mid-afternoon here in the U of AZ time lapse movie (as well as the thinning of the dust haze we had yesterday) here.
The weather ahead
No rain has popped now in the mods for some time regarding the passage of a trough on the 17th, just some wind with it, though not anywhere like what we just had. In the drought relief department, it was another great day yesterday for portions of KS and NE as shown in the WSI Intellicast radar-derived precip map:
The 24 h precip totals for the US ending at 5 AM AST this morning.
Of course, the title refers to Dickens’ little known sequel (and frankly, a lightly regarded one) to his popular, “Great Expectations”. Dickens fully expected that by rushing out another novel similar to “Expectations” that a financial success similar to the one that “Expectations” had garnered for him would be easily acheived.
However, like most sequels, his effort was weak and appeared to be thrown together to merely take advantage of a gullible public. However, and much later, his sequel came to be regarded as a semi-clever, though lightly disguised, slam on the early English weather forecasting system, which was, of course in those days, was map-less, model-less, and mainly consisted of limericks and folk sayings:
“Birds flying low; beware the Low1.”
Forecasts were quite bad in those days in which Dickens lived, naturally, ships went down regularly due to unforecast storms, and Dickens wanted to dramatize this to his readers in his sequel; the various twists and turns in the plot of that sequel now thought represent ever changing, unreliable forecasts. He had hoped, with his satirical sequel, to provoke advances in weather forecasting, which he did. Isaac Newton, joined by Leibnitz, took wind of the Dickens sequel, and together they invented calculus, a tool which which allowed the calculation of the movement of air using the laws of fluid dynamics.
—-End of historical antedote2——————————
A surprising overnight rain
Well, even C-M and associated models like the Beowulf Cluster as of the 5 AM AST run on the 8th, did NOT see 0.38 inches from “Joe Cold Front”, who was supposed to pass by as a dry front, not a wet one. Still, it was fantastic surprise, one that could have only been made better by having forecasted it from this keyboard; going against the models big time. And THEN to hear Joe’s rains pounding on the roof as he went by between 10 PM and midnight. Oh, my, euphoria. BTW, the temperature dropped from 60 F to 43 F, too. Whatafront! Thank YOU, Joe.
You can see some rainfall totals from the Pima County ALERT gages (April 8th-9th rainfall). We “northenders” pretty much got the bulk of it, with Pig Spring, 1.1 miles northeast of Charoleau Gap leading the way with great 0.71 inches. Ms. Lemmon was not reporting at this time because it fell as snow. So look for a frosty Lemmon this morning. BTW, Sutherland Heights picked up 0.42 inches, and had “pre-rain” gusts to 58 mph! Whatastorm!
Continuing now at 7:21 AM after a “godaddy.com”/Wordpress meltdown an hour ago.
BTW, all the haze out there is dust under the clouds, not fog. Its pretty unusual to see something like this, especially after a good rain, so you’ll want to document it with photos and a little paragraph or two about it, and how it makes you feel. There was so much dust raised behind Joe throughout AZ and Cal that its rainband could only do away with that dust within it. This overcast situation should gradually breakup as the day goes on into more cumuliform clouds, ones with large breaks between them, the dust probably hanging on most of the day. With the -10 C level, the usual ice-forming level here at just around 11,000 feet above sea level. So it should be easy for the taller Cu to reach that and spit out some isolated precip later in the day.
Signs that the forecasts were going bad in a major way was when lines of clouds and some with precip formed in southwest Arizona late yesterday afternoon. Here’s a nice map of that development, one in which caused the tiny brain of C-M to think that it might rain, probably you, too, and anyone else that looked.
5:30 PM AST visible satellite image from the U of WA.5 PM AST 500 millibar map. You can just see that little line of clouds, and you can also see how the jet, wrapping around San Diego and headed this way, partitions the clouds. I think this is called a “teachable moment.”
Some scenes from yesterday’s dust, from the beginning. Save these for posterity:
8:21 AM. No sign of dust.1:47 PM. Dust haze becoming increasingly noticeable.2:00 PM sharp. Mr. Cloud Maven person’s cap blows off about 40 yards down the road in spite of having warned others about having this happen.2:04 PM. Dust increasing rapidly, wind peaking at 55-60 mph in the Sutherland Heights district. Twin Peaks no longer visible.3:02 PM. Small Cumulus (humilis and fractus) increase in coverage as dust limits visibility to around 10 miles.6:38 PM. The yellow sunset, indicative of large aerosol particles associated with dust.
————————–
Feeling good about rain here, feeling good about rain there
Not only can we exult over a surprise rain of some substance, but look what has been happening in the droughty central Plains States. Below, from WSI Intellicast’s 24 h radar-derived rainfall amounts for the US (april 8th, then April 9th at 5 AM AST. Especially take stock of the amounts over the past two days in those worst drought areas of Kansas and Nebraska. So great! And this is only the beginning of a huge rain/snow event in those drought areas!
24 h rainfall ending at 5 AM AST April 8th.
The End
—————————————————
1Hygroscopic insects adsorb water molecules and are weighed down in conditions of excess humidity, the kind that often precedes a storm. Birds then fly lower, too, to grab lower flying insects, or so the saying goes. (I am quite pleased by the kind of information I provide for you almost everyday.)
This whole situation, in spite of the inclinations seen in “spaghetti”, has gone to pot. Well, actually, to the north more than foretold days ago. No rain is now foreseen here for another week or two.
But instead of discussing in minutiae what went wrong, and why CM fell for it, that is, go through a bunch of hand-wringing about how bad our models are, even with some chaos thrown in (produces “spaghetti”), let us instead change direction for awhile, a diversion really, and consider the two forms of anarchy today: good anarchy, and bad anarchy.
We begin our discussion with an example of “good anarchy”, shown below:
Here, at an entrance to the University of Washington, conscientious citizens exhorting their fellow citizens to be as good as they can be and not break laws. While it was illegal to write on the wall, you can see that they were good-hearted people, ones that might pick up litter as well.
In contrast, below I present an egregious example of quite “bad anarchy.” Please note the clear message by the authorities on the sign at right:
This was horrific, shocking. Here people, but not me, violate a clear edict about walking past a sign with a black pole marking the point you are not supposed to go past. And the violators seem to have no remorse about they have done, but are just kind of ambling along. What has happened to us? Perhaps the woman on the left is bowing her head in shame. Maybe THAT is the only thing we can take away to boost our spirits over this sad scene of otherwise happy, non-chalant acting people in violation of the law. I will never forget this scene.
Yesterday’s clouds
We did have a nice sunset; so many here. Hope you saw it. Pretty much an all daymlollipop lentiular cloud downwind of Ms. Lemmon yesterday, too. Here’s the U of AZ time lapse for yesterday. You can really see how these clouds hover, shrink and expand, disappear, reappear, as the moisture grade changes.
6:45 PM. Altostratus with virga, lit from below due to a distant hole that allowed the fading sun to illuminate this portion of the As clouds and the light snow falling from them (virga).
7:03 AM. Ac len downstream of Lemmon.1:13 PM. Still there.4:43 PM. Some more over there, too.
Yesterday, that is. It felt like I never left. Only 49 F here; was 55 F in Seattle yesterday.
But the main thing that made it seem “so Seattle” was the persistent low Stratocumulus overcast, almost no sun whatsoever, and a little rain. We picked up another 0.03 inches in a couple of morning episodes of R– (an old weather texting1 shorthand for “very light rain”) to bring the storm total here to 0.55 inches. Of course, the best part of that overcast was that it allowed the ground to be damp for another day, helping the spring grasses and wildflowers by keeping the soil moisture in the soil and not flying away under a hot sun. The worst part of the overcast that lasted almost all day, was that Mr. Cloud Maven person had the day completely wrong–thought it would break open in the afternoon to “partly cloudy” and so he was as gloomy as the sky. You see, as a weather forecaster, you can’t even really enjoy a nice day if you didn’t predict it. Had some sad 75 F days in Seattle when I only predicted 69 F; everybody having summer fun but me.
Enough nostalgia, here are the clouds, even if you have no interest in seeing such boring clouds again:
6:56 AM. Interesting little punctuated lenticular. Mr. “CMP” has just finished his long blog and thinks the sky will break open in the afternoon. Hah!
8:00 AM. Stratocumulus tops Samaniego Ridge–with the turrets, you might lean toward adding the descriptor, “castellanus.” Note blue sky here, if you didn’t see any at all yesterday. No precip evident.8:02 AM. Looking north toward S-Brooke. Fine shafts of precip emit from Stratocumulus clouds indicating those regions in the cloud where there was more liquid water at one time, that is, where these clouds are humped up like those Sc clouds on Samaniego Ridge in the prior photo (the precip from those clouds may have been out of sight). But, was the precip shown here due to ice or the colliding drops process? I wasn’t sure at this point. You see, after a storm, the clouds can be real clean, almost oceanic-like meaning they have LOW droplet concentrations, and when the droplet concentrations are low, the drops are usually larger and can get to sizes where they can stick together when they collide (think 30-40 micron droplet diameters). You probably don’t have a clue about those sizes, but it sounds great if you see rain like this and tell a neighbor that, “those clouds might have drops larger than 30-40 microns in diameter near cloud tops.” Instant neighborhood expert!
8:06 AM. Then the clouds to the west of Oro Valley and Catalina began to produce fine precipitation and advance on Catalina. How nice. Definitely was looking like a true drizzle event (caused by colliding drop rain formation process), at least to me at this point. That process is a rare event in AZ when very light rain or true misty drizzle (tiny drops, close together) forms like that. Usually our clouds have too many droplets from natural and anthropogenic sources and the cloud droplets stay too small to collide and stick together, instead bumping around like marbles with all the surface tension they got. And then because they’re all tiny, they don’t have much impact when they hit, there’s not a lot of velocity difference like there would be in a cloud with a broad droplet spectrum, the kind of spectrum we see in “clean” clouds where drops bigger than 30 microns are a plenty. Note trails of precip coming down in center. BTW, to go way off topic, to distract from how bad my forecast was, in “hygroscopic” seeding, particles like salt are introduced at cloud base to encourage the formation of rain through this process in polluted Cumulus clouds. Worked in Saudi, based out of Riyadh, winter of 2006-07, flying in a Lear jet, helping to select Cu for random seeding using that methodology2. Our office at the government met building, I recall, was cleaned by the “Bin Laden” group. Hmmmm. Maybe its a common name there, to go even farther off topic.10:09 AM. So Seattle! (Have to make up for that last bloated caption.)4:49 PM. And that’s your entire day.6:27 PM. Sunset tried to do something. But, like the day, it was like that sugar icing on a stale dried out cinnamon roll, just didn’t quite make it, though cinnamon rolls are quite good as a rule.
Today’s clouds
Some residual small Cumulus, maybe clumping into a larger group this morning for a bit, which you would then refer to as Stratocumulus. Should gradually diminish in size and coverage until almost completely clear in the afternoon. Expect a north wind in the afternoon, too.
The weather ahead
There isn’t any, well, not right away, but WAY ahead….
Chances for rain begin to pick up after the 19th as we enter the “zone of curl”, “cyclonic curls” in the upper atmosphere with a lot of “vorticity” in them again, with temperatures falling back to normal values. Pretty tough to have warm weather for long at this time of year in AZ. You see, its troughs like to “nest in the West” in March, April, and May, even when they’re not strong and far enough south to bring rain, maybe only wind. Its a climo thing, and it causes many areas of the West to see an increase in precipitation in March from February, and also halts the rapid rise in spring temperatures (especially in Seattle, hahahaha, sort of).
This because the global circulation pattern, responding to the climb of the sun in the sky and warming continents in the northern hemisphere, those forces acting on the position of the jet stream, and weakening it here in the NH (northern hemisphere), is changing the jet stream pattern so that storms begin to move southeastward from the north Pacific across the Pac NW into the Great Basin area in the spring, bringing cold north Pacific air into the West. There was a great report about this phenomenon by old man Bjerknes out of UCLA with his Ph. D. grad student, Chuck Pyke, back in the mid-1960s. Pyke was a UCLA sports nut, BTW, to add some color to this account.
We won’t see that “trough in the West” pattern for awhile here in our “oasis of warmth” now about to begin, but count on it returning, as it appears to do late in the model runs from last night. Climo is forcing it.
The End, except for footnotes.
——————————————- 1Yeah, that’s right. Weathermen, as we would say it then, were way ahead of their time, “texting” each other long before kids thought of “texting.” You might write a weather friend, if you could find one: “We had a TSTM to the S with FQTLTGCCCG ALQDS last night for a few H. MVD N.” PIREPS, SIGMETS, too, were all “texted” and texted by teletype! Tell your kids.
2Was under the aegis of Research Applications Program (RAP) at the National Center for Atmospheric Research (NCAR) in Boulder, CO. Money was good…though not nearly as much as you would make as a TEEVEE weather presenter (hahaha). I was a post retiree guest scientist for RAP NCAR. Clouds could be real bumpy there in Saudi, thought I was gonna die once as bottom dropped out of the Lear going into Cumulonimbus at night that one time. Pilot liked to cut it close between the hail shafts and the rising parts of the Cu with little or no precip, using his aircraft radar. But sometimes, it was a little too close…and we got into the shear zone between a strong updraft and the downdraft.
Well, here it is, the NOAA Catalina spaghetti output for March 8th, 5 PM AST, hold the sauce:
The 564 decameter height contours for 500 millibars over Catalina and environs (in the center) on March 8th at 5 PM. The yellow line is the 5 PM AST model prediction, and the gray pixel in the lower left corner is what’s left of the same contour (after I cut and pasted) yesterday’s 5 AM AST prediction. They were pretty much showing the same thing.
The plot at left, with likely a Guinness record for a long, thin caption, pretty much guarantees a big trough of cold air here by then, another door opens into winter, which seems to be gone right this moment, and, being March, you might be thinking, “la-dee-dah, no more winter here in southeast Arizona.” But as I often point out to my reader, and while trying to be a bit delicate about it, “You’d be so WRONG! I can’t even describe how WRONG you would be!” So keep that balloon-like parka ready, heck, there could even be some snowflakes with this.
And, of course, I am a be little disappointed, well, royally, because you should have seen this coming in the red dot-plot at left for Catalina on March 8th already, and I wouldn’t have to admonish you again. Oh, well.
BTW, the “red dot” is a baseball term used to describe the appearance of a slider coming at the batter–there’s a red dot in the center of the ball caused by the spin and where most of the red lacings appear to be concentrated because the pitcher had to grip the ball a certain way. Seen’em, at one time. Of course, you wouldn’t remember the great pitchers like Lee Goldammer of Canova, SD, or Dave Gassman; the latter amassing over 4,000 strikeouts in South Dakota summer baseball league play. It was a big story in the Mitchell Republic–they keep track of that stuff there (amazing and charming). Lee Goldammer pitched a DOUBLE header and his team won the SD State Tournament back in the late 1960s. (All true!) You see, Lee Goldammer struck me out on three pitches in 19721. Man he was good! I had hardly gotten to the plate, and I was walking back again!
Had a nice sunset a couple of days ago, some pretty Cirrus clouds again. Where I’m from (Seattle), Cirrus and sunsets are generally obscured by Stratus, Stratocumulus, and every other kind of cloud imaginable so that you don’t see them often because those clouds extend for thousands of miles to the west where the sun is setting.
6:28 PM, February 27th, not last night.
————————————–
1I was working that summer for North American Weather Consultants as a “radar meteorologist” in Mitchell, SD, directing up to four cloud seeding aircraft around thunderstorms. But when it wasn’t raining, I could play baseball for the Mitchell Commercial Bank team. The project was under the aegis of the South Dakota School of Mines, was statewide in 1972. Unfortunately, for the people on the ground, one of the aircraft was seeding a storm in June of that year hat dropped 14 inches of rain in the Black Hills, and the ensuing flash flood took over 200 lives. “Hey”, it wasn’t one of my aircraft. Ours were in the other end of the State.
Cloud seeding was absolved in the disaster, which was correct; the weather set up that day did it. No puny aircraft releasing stuff could have had any effect whatsoever. However, had that 14 inches filled a dry reservoir to the top and saved a city from a water famine, what would the seeding company have claimed in that case?
I know. It happened when I worked a project in India, the water famine there making the cover of Time magazine in 1975. The reservoirs in Madras (now, “Chennai”), India, where I was assigned by Atmospherics, Inc., as a “radar meteorologist” whose job again was to direct a seeding aircraft around storms, were at the bottom, just about nothing left, when I arrived on July 14th, 1975.
But on the third day I was there, July 16th, 1975, a colossal group of thunderstorms developed over the catchment area of the Madras reservoirs and, naturally, our one twin-engined Cessna was up seeding it. It was my job to see that we had a plane up around the thunderstorms.
Five to 10 inches fell in that complex of thunderstorms with tops over 50,000 feet, and there was a flow into the Madras reservoir (oh, really?) for the first time in the month of July in about 14 years. July is normally a pretty dry month in the eastern part of India, with Madras averaging just over 4 inches, only a little more than we do here in Catalina in July. The main rainy season in Madras is October and November, during the “northeast” monsoon. This is what those giants looked like:
Looking west-northwest from the Madras International AP at Meenambakkam, India, 1975.
But as a meteorologist, I saw that a low center had formed aloft over southern India, weakening the normally dry westerly flow of the “southwest monsoon” across southern India after it goes over the western Ghats. This weakening allowed the moist air of the Bay of Bengal to rush westward and collide with that drier westerly flow and set up a “convergence zone” where the two winds clashed and the air was forced upward forming huge, quasi-stationary Cumulonimbus clouds.
Below, what I look like when I am in India and starting to be skeptical about this whole thing, “Is this going to be another cloud seeding chapter like the one in the Colorado Rockies, to graze the subject of baseball again?”
First row, 2nd from left. Our pilot sits next to me.
As before in Rapid City, the weather set up the deluge; no aircraft releases could have made the least difference in such powerful thunderstorms. While the leader of the seeding project did not take credit for the odd flow into the reservoir that July, it was pointed out to the media, without further comment that, “yes, we were up seeding it.”
The odd storm with that comment, sans a description of the weather set up that did it, made it too obvious to the uninformed that seeding had done it. The Indian met service was, of course, outraged, and did their best to “fill in the blanks”, but the sponsor of the project, the Tamil Nadu state government, was unconvinced because it was obvious to them what had happened, and, after all, it was what they paid for!
I had already been disillusioned while working as a forecaster for a big, randomized cloud seeding project in Durango, Colorado by 1975, and this project was to add more “fuel to the reanalysis fire” that I was later to be known for. (hahaha, “known for”; I was despised in some quarters for checking their work after they had published it and it was being cited by big scientists, and I mean huge, like the ones in the National Academies, but like you when you thought summer was here NOW and there would be no more cold weather, THEY were so WRONG! I can’t even describe how WRONG those national academy scientists were, like the ones in Malone et al 1974 in their “Climate and Weather Modification; Progress and Problems” tome.) ((I knew they were wrong because they talked about clouds and weather associated with cloud seeding experiments in the Rockies, and I was seeing how at odds those clouds and weather was with the way it had been portrayed in the journal literature by the scientists who conducted the precursor experiments to the one I was working on in Durango.)) (((Wow, this is quite a footnote, if it is still one.))) ((((Still worked up about that 1974 National Academy of Sciences report, but don’t get me going on the 2003 updated one, which they botched royally, including not even citing the work I did correctly! How bad is that??????)))) As the title of today states, “seeing red.”
The reason for going to India in the first place was that it had been indicated in our peer-reviewed journals that randomized seeding in Florida, that clouds like ones in India, had responded to cloud seeding. Besides, I had an ovwerwhelming desire to see giant, tropical Cumulus and Cumulonimbus clouds up close! BTW, the Florida results fizzled out in a second randomized phase.
But first, continuing from yesterday: “…and a few small to moderate sized Cumulus (humilis and mediocris) clouds as well to go with the high and middle clouds.”
Sorry I took so long to finish that up, but it was worth the effort because it was pretty darn accurate.
The storm on the doorstep
Here is your very excellent Catalina forecast as of now (4:50 AM) from the computers at the NWS. There is a statement on the exciting New Mexico weather, posted by the Tucson NWS here. You can feel the excitement in NM in this message they consider quite special, labeling it a “Special Statement.” Hope our Arizona guys and gals get on board with the NWS in ABQ and issue something special soon! Being weathercentric, of course, I am at one with the ABQ office even now.
Here’s a depiction of the incoming storm from our best model, that at the U of AZ, one that downsizes the “WRF-GFS” model to smaller scales so we can see what happens in our local mountains and valleys as it barges across California and then into Arizona on Saturday. Precip is shown to begin on the Catalinas before dawn on Saturday, but probably won’t reach here for a few hours after that. The model onset time here in Catalina is 8 AM AST on Saturday. However, this model tends to run a bit fast in these situations, so it may be mid-morning before those cold, cold raindrops start falling. But, 8 AM vs maybe 11 AM AST? Amazingly close no matter how you put it. It just shows how good our modeling systems have gotten over the years.
The amounts? Seems measurable rain is certain here in Catalina–the flow pattern jetting against this side of the Catalina Mountains favors us here. The finest scale model at the U of AZ, the first place to look, is showing a range of values between 0.25 and 0.50 inches, oddly corresponding with a ludicrous guess made too far in advance here a few days ago. Hmmm. The Catalinas are shown to get more than an inch and that calls for a celebration.
Here is the scoop from the 11 PM AST U of AZ model run for total precip (snow on the Catalinas again, the best kind of precip because it just sits there and soaks in when melting):
Valid at 2 AM AST Sunday the 10th, the storm is long gone from Catalina at this time but still adding some in the mountains up to about here.
Out of character a bit, but also since we’re on the edge of the predicted range of amounts, I think the bottom is closer to 0.08 and the top likely amount is 0.38 inches, with a “median”, most likely amount of about 0.23 inches, to be a little silly here.
Clouds today?
Probably (and this time I will examine the TUS sounding more carefully than yesterday), just a few isolated Cumulus clouds again, likely dissipating during the afternoon, and a couple of Cirrus clouds.
The clouds tomorrow (more interesting)
One of the interesting cloud formation zones for Arizona is over and downwind of the mountains in northern Baja (Sierra de Baja California). Gigantic plumes of Cirrus/Altostratus ice clouds often form in these situations as moisture at high levels from the Pacific Ocean (located west of Baja, California) travels over those mountains. Those clouds would be something akin to standing wave clouds, lenticulars, but because the air is pretty moist (“ice saturated”) wrapping around this powerful low, they don’t evaporate downstream once having formed but end up as a huge, icy plume across central and southern Arizona. I think we’ll can see that start to happen today, first in the lee of the Sierras of California, as the jet stream works it way down the West Coast toward us.
Eventually, the higher level moisture dries out over those Baja mountains, as it will later tomorrow, and the icy plumage source ends, and many times we see the end of that plume from those Baja mountains (Cirrus/Altostratus clouds) as a huge clearing that, oddly, preceeds the real storm; the surge of lower level clouds that carry the precip. And with that clearing as well, the passage of the core of the jet stream (in the middle levels) above us.
I know many of you have seen this sequence over and over again, the clearing of a high dense layer of clouds from the actual storm that’s on its heels.
Such a separation in those two clouds systems, the high and the low, can lead to spectacular Catalina sunsets. Tomorrow, out on a limb here, is the kind of day where that could happen–the sun sets in the distant clearing to the west as the shield of icy plumage overhead passes.
Yesterday’s clouds
Yesterday was another one of those especially gorgeous days here in the wintertime. Delicate patterns in Cirrus, as well as the dense patches. Then, a few lower Altocumulus clouds above scattered small to medium Cumulus clouds against a vivid blue sky and limitless horizontal visibility. Here are some examples:
7:47 AM. Old Cirrus (foggy stuff above palm tree) below in altitude newly formed Cirrus (flocculent specks to left and right).
10:31 AM. Only the exceptional cloud maven junior would have noticed this rogue Altocumulus castellanus masquerading as a Cumulus. Its betrayed by those specks of Ac floccus around it. Also, if there was a true Cu fractus nearby, you would have noticed a tremendous difference in the relative movement of the much higher Ac cloud and the real Cu.
12:02 PM. Last of the high clouds (Cirrus spissatus) approach Catalina with Cumulus fractus and humilis starting to form.
2:36 PM. One of the best shots of the day; small Cumulus with a trace of Altocumulus perlucidus above.
5:51 PM. Though it was clear to the west, we still had our sunset color on the Catalinas, and an orange reflection on the bases of the last clouds hanging on above them.
Kind of rushing around today, hope this is intelligible….
“Storms” at 30,000 feet, single ice crystals falling from various varieties and species of Cirrus clouds. That’s about all we got for “weather” in the next few days as Cirrus creeps up from the tropics into Arizona. But those Cirrus produce great sunrises and sunsets, so have camera ready. And while not much is happening, you should practice logging what you see up there.
Cirrus clouds are the first clouds we see when something is up with the weather, even when it stays up high, but even in these “storms at 30,000 feet”, the moist level tends to decline over time, meaning there might be a chance for mid-level clouds to appear….such as, you guessed it, say, Altocumulus clouds, clouds mainly comprised of droplets, in the near future. That would be pretty exciting; mo’ better sunsets!
Maybe if it was a “cold one”, an Altocumulus cloud with virga hanging out of it, would give you a great opportunity to talk with your neighbors about the Wegner-Bergeron-Findeisen1 precipitation mechanism (be sure to use all three names to attain the greatest personal stature with them).
——–Warning! Beginning pedantic unit———-
What’s “WBF”, you say?
Hell, you see it all the time! Well, actually only once in awhile here in Arizona. Below, in a pictogram, is a representation of “WBF in action” from a few days into our cold spell just passed so you’ll know when you see ice virga hanging from a droplet cloud you’ll know what the HELL has happened up there. (Dry spells, such as we are in now, make me want to cuss that bit more.)
The background.
Your car has been parked outside all night, and the air was moist. You finally wake up and go outside and you see that dew has formed on your car windows, well, all over. But even though its a bit below freezing, not too much because we’re in Arizona, you also see that in a couple of spots, ice has formed; “horror frost” crystals as we call them here in Arizona because we don’t like frost and cold air of any sort. (The real name is “hoar frost”, and watch out how you use that in a sentence.) The remainder of the drops you see on the car are still in the liquid phase, or have JUST frozen.
But here’s the exciting, magical thing that happens around those “horror frost” ice crystals, demonstrated with a photo through a car window. I’ve added stuff on this jpeg to help explain the magic show going on when the two, liquid and ice, mingle.
A recent example of the WBF in action.
And what you see that has happened here is the same thing that happens in clouds when ice and droplets mingle, are co-located so-to-speak. When an ice crystal forms in a droplet cloud, it becomes a vapor hog, water molecule hoarder, because at water saturation, the condition that results in the drops forming in the first place, its SUPERSATURATED with respect to an ice crystal! Amazing, and CRITICAL for life as we know it on this planet because most of the precipitation that falls in mid-latitudes is related to this process. We would have virtually no precip here in Catalina ever without this process.
What does that mean? When the two phases are in proximity as here, the droplets nearest the crystal evaporate, and the ice crystal grows and falls out, usually, as precipitation. Most rain on this planet is due to that process! There are two others that are also important, all ice, all liquid, but today I’m only talkin’ WBF, the “mixed phase” process.
In a cloud, especially a flat one like Altocumulus, this “mixed phase” condition results in ice crystals that grow too heavy to stay in it–its kind of like a “Thanksgiving-for-ice-crystals” inside a mixed phase cloud, and they fall out in those fine strands because they are so fat.
In another way, the ice crystals in a mixed phase cloud are like a low pressure centers, the droplets high pressure centers and the molecules move from high to low pressures.
Mixed phase clouds would go away completely, of course, UNLESS there was some upward motion to keep new droplets forming. But, as in “Ghosts of the Perlucidus” blabbed about here a couple of days ago, sometimes there isn’t enough upward motion to keep the droplets “alive” and only a ghostly remains of the droplet cloud can be seen in a thin patch of ice.
Further detective work re the above jpeg.
Those ice crystals has to have formed when the drops around them were still liquid, probably just as the window reached a freezing temperature or a hair below. If all the dew drops had frozen at once as clear ice, you would not have seen this crystal growth happen because everybody is in the solid phase, no “high or low pressures.” So, while dew drops were forming and growing while the temperature dropped below freezing, there was something quite unique about a particle on the window that caused ice to form when most other places were quite happy to be liquid. We call those special particles that might have triggered an ice crystal, “ice nuclei”, though, too, there may have been a window surface imperfection that did it.
Anyway, ice nuclei are always much rarer in clouds than “cloud condensation nuclei”, particles that the cloud droplets form on. A demonstration of that is in that photo above.
Cirrus clouds, almost never having water, “don’t need no water” because its often supersatured with respect to ice above 30,000 feet without having a droplet cloud. So, even without the water phase, an ice crystal can get fat and fall out in many Cirrus clouds, such as the revered, Cirrus uncinus with its pretty trails. Veil clouds like Cirrostratus? Not so much growth.
———-End of pedantic unit———
Yesterday’s clouds
You may have spotted those creepin’ Cirrus at sunset yesterday. If not here they are, a classic example, ones that kind of drift up to the north out of the tropics into Arizona that from weak circulations down there, even in drought times here, periodically passing overhead, keeping our skies from being boring, particularly for those many of you who out there who are cloud-centric, head-on-a-swivel when outdoors:
5:48 PM. Distant Cirrus, loaded with a few contrails because there’s an airway down there, creeps toward Catalina. Outta be here by now. Its dark and I think I can make out something so this is not really a forecast because I kind of cheated by looking at the sky just now but I WOULD have said that without looking… And if those clouds did get here, there might be nice sunrise for you.
What ahead?
Of course, there’s some rain on the model “horizon” (IPS MeteoStar rendering of WRF-Goofus model), but like that “puddle” on a desert highway on a hot day that you never get to, and I’ve tried, because it moves away as you speed down the road, the “puddle” staying the same distance away, our model rains seem to do the same thing. I’ve used this metaphor before, but I can’t think of a better one. I think its pretty good, too; damn good, really, to cuss a bit more. :} Here are a couple of examples of rain in southern Arizona from last night’s global model run to get your hopes up, most likely to be dashed:
Valid for 5 PM AST, January 28th, Monday. Green areas denote the rain the model thinks has fallen in the prior 12 h. Yeah, right.
Valid for 5 PM AST, February 1st, Friday. I would gladly eat my words with whipped cream on them if this happens.
The END, FINALLY!
—————————-
1They’re not “mostly dead” now, but “all dead”, to crib a line from “The Princess Bride.”
Title properly sung to “Rawhide1“, a western theme song for a TEEVEE show known by heart by all us TEEVEE viewers of old, and how it might be sung today by a weather-centric cowboy, one that lived in “a area” of drought, like us.
On with the story…
There was a couple “stray” model runs (hahaha) yesterday, ones that dried up all the storms but the BIG ONE tomorrow night and Friday. Those runs were quite bad ones; looked like the CDO wash today.
It had been penned from this keyboard recently, if you can say, “penned” in the context of a keyboard, that a SERIES of storms were on their way to Catalina after the drencher Thursday night into Friday, so I had a vested interest in not showing those runs.
I know, too, when you read that C-M person had said that there were a lot of storms coming that you were probably ecstatic. Maybe thought the drought might be vanquished by “a few good storms” over the next two weeks to a month. Maybe you did something fun that day after you read what I posted about a lot of storms ahead; maybe called in sick and went to Ms. Mt. Lemmon to see if you could see some precursor clouds off to the west.
Therefore, having written about all those storms in my last post, I had the responsibility to ignore the later model runs with no rain in them (after Friday) and wait for those other rains to re-appear. (Its funny, but it happens.)
I am pleased to report, after not telling you about those dry model runs, that the series of rain days the model had before have magically re-appeared, though no as “juicy” as before, and I can resume telling you about them! This is so great!
Here are a couple of examples from last night’s WRF-GFS run from data taken around the world at 5 PM AST, the first for Sunday morning, 5 AM AST. The two panels below are posted in smaller sizes because they have less credibility being as far in advance as they are; click on them for a larger view.
What about the drencher coming in tomorrow night and Friday? Let’s let the highly paid TEEVEE weather practitioners take that today. They’ll be all over it, and they’ll do fine. I’m sure… They’re all pretty good.
Sunday afternoon, the 19th, new rains approach.Morning of the 27th. Good fantasy rain here; too far out to count on, but. “hey” its something to write about!
Yesterday’s sunset
What would a C-M be without a sunset picture, this of Cirrus clouds.
5:27 PM.
—————
1Frankie Laine remindner here; a great song with a lot about weather and flooding in it; cuss word, too, bold for those days. Had Clint Eastwood in it; whodda guessed he’d be still making movies 100 years later?
Pretty upset this early AM to find that the US’s Weather Forecasting and Research-Global Forecast System (WRF-GFS) model run, a model costing millions of dollars BTW, ingested last night’s 5 PM AST global data, BUT then threw up an identical twin that matched the Canadian Enviro Can model output that came out 24 h earlier! It was unbelievable to see this, humiliating really, something akin to a reverse nose job.
Recall that the USA! model had rain here and a big cold trough right over Catalina on the evening of December 9th into Monday morning the 10th. The Canadian model had that SAME trough over Cornhusky Stadium, Lincoln, Nebraska!
The Canadian model was right.
Here’s are the two forecast maps made within 24 h and each for for the SAME DAY AND TIME by our own WRF-GOOFUS model: on the left, the rainful run from the previous day that made me so happy (until I had some “spaghetti” and saw it was likely a bogus output). The panel on the right is the sickening output from last night, both rendered by IPS.
Valid for Monday, December 10th at 5 AM AST. Sweet! From last night, also valid at 5 AM AST, Monday, December 10th. Horrible, unbelievable amount of change between the two. Makes you feel sad for weathermen and weatherwomen that have to deal with these things.
I really wanted Enviro Can to eat some crow with their forecast of MY trough over Nebraska. But no! “Bow down to Canada”, as heard here if you substitute in your mind the word, “Canada” for “Washington.” Hey, its got the lyrics at this site and so it should be pretty easy for you to sing along with it.
BTW, the Canadians (Enviro Can) don’t feel they have to show “spaghetti” plots to reveal how bad their numerical forecasts might be because they are always so right (in the 144 h time frame available from Enviro Can). “Don’t need no spaghetti.”
Can we say the same?
Doesn’t seem like it. We need “spaghetti” so we can see how bad our model forecasts might be. Calling Obama now…. not “happy with crappy”, to quote some overseas manufacturer’s creed, here. OK, our models aren’t exactly “crappy” but they aren’t as good as they should be.
Too, I have to deal with Canadian relatives that will be gloating today, I am sure. Maybe this spectacular example of “model divergence”, as we would call it, Canadian vs. US, is the talk of Canada today, and that’s what makes today’s wrf-goofus output sting so much.
I really want to call President Obama on this and tell him about it; I know he would add it to his list of things that need to be fixed in our country. Even if you have only a tinge of jingoism, you HAVE to be upset that the Canadians in their big little country, have a better weather forecasting model than we do! I think I am going to have to lie down for awhile…calm down.
So, what is ahead in our weather?
Of course, we have to look at the Canadian model first to get the most reliable one to see if they have anything for us… (hahahahah, sort of). I always do look at that one first, but I don’t brag about it. The summary of last night’s Enviro Can run, out to 144 h: they got nothin’ for us, just some cooler air over time. Cirrus clouds will be floating by from time to time as they do on most days. Did you know that Cirrus is a precipitating cloud? Yep, little ice crystals are always settling out leaving those pretty trails. Mt. Everest would know this…
Hope you had some good log entries describing the varieties and species of Cirrus… If you did, you’ll be getting closer to getting that Cloud Maven Junior Tee.
7:01 AM. Sunrise Cirrus.5:32 PM. Sunset Cirrus, maybe with a contrail in there, dammitall.
A day of pretty Cirrus and a nice sunset yesterday:
5:35 PM.
Now for some more of that Catalina climo, featuring December
(Most of these data below are due to the folks at Our Garden right here in Catalinaland just off Columbus._
First, the rainfall frequency chart for December. Not much going on. Chances of rain on any day about the same as any other, no trend up or down during the month, except for that one peak. Below this chart, in the monthly averages for the October through September “water year”, you’ll see that the average rainfall has jumped up considerably in December from November. Yay!
But will it rain at all in December 2012?
Let’s check…and also look, just for the HECK of it, whether any trough/storm is headed here in the 11th-13th rain frequency peak shown in the first plot…to see whether the atmosphere “likes” to have a little rain in Catalina in that time frame this year.
Below, the USA WRF-GFS model output, again rendered by IPS MeteoStar, from the global data taken at 5 PM AST valid for Monday, December 10th at 5 AM (close enough):
Astounding! A strong trough with rain IS predicted in about that time frame where the chance of rain in our 35 year record peaks, though a bit early. If this map verified, rain would be ending at about the time of this map, 5 AM AST on the 10th, it would be very, very cold, probably in the upper 30s in that rain. Amazing.
But let’s check with the superior Enviro Can model from the Canadians, our friends to the north, because-its-built-on-the-Euro-model-where-they-have-more money-for-big-computers-and-better-models-than-we-do.
Not even close to the prediction by the USA model!
Unbelievable difference, in fact. In the USA model, the apex of the trough is over us in Catalina and in the superior (or will it be?) Canadian model, its over the “‘Braska” Cornhuskers, Lincoln, NE, maybe ONE THOUSAND miles farther east!
Unbelievable2. This is a phenomenon, BTW, which does happen from time to time, that is called, “model divergence”, to put it mildly.
The NOAA spaghetti factory, which I have annotated for you below:
Outstanding forecast reliability is indicated in the Pacific, off Asia, but who cares?
Sadly, only mediocre reliability indicated here in the Great SW USA, as shown in the wanderings of the blue lines.
But will a trough be close to us?
Pretty much count on that because so many blue lines feint to the south in interior of the western US. I think we’ll surpass the Canadians this time…
There’s still a chance of rain on the 9-10th, but its pretty slim. Having cold air invade us, to varying degrees is pretty much guaranteed even if sans rain because that nearby trough will drag cooler air this way as it goes by.
Its the AMPLITUDE that matters here, and in our USA model, that is not so well known. In fact, the blue lines, with so many of them north of us are telling us that the actual forecast map from last night’s global data is an outlier model run; can’t count on it. It will likely come and go on the future model runs.
