Its not about hairdressing. Its about the “curl of the low” and its jet stream configuration, as shown here by here (IPS MeteoStar):
Valid for Wednesday, March 20th, 2013. Want to see if anyone reads the captions.
Oh, shoot, this is for a storm and cold blast about 13 days from now! (Secretly, with the storm tomorrow so well predicted at this point by all—might as well show you that it might not be the end of March storms.)
OK, lets try again to get a more timely forecast map:
Oh fer Pete’s Sake. This is valid for 256 h from last night, or the morning of March 18th! But we’re in the curl AGAIN!
Oh, shoot, this ones for 256 h or almost 11 days from last night! What is going on here?
One more try for something relevant, well. its all relevant (suggests we’re in the “trough bowl”:
Finally, valid for 11 AM AST tomorrow morning, this from last night’s WRF-GFS run.
Maps look kinda similar don’t they? Hence, talk about the “bowl” phenomenon where troughs “remember” where they’ve been like your horse does, and they know where they should be. There’s a long fair weather gap between the one tomorrow and the ones later; don’t get fooled by thinking winter’s over.
This last one for tomorrow suggests the rain is either here or imminent at 11 AM AST as the jet core at 500 millibars, is already deployed to the southeast of us by that time. The timing of all of what happens tomorrow is pretty good for rain amounts since with the chilling air aloft (making it easier for air to rise from near the surface), the cold front will blast across Catalina in the later afternoon. This means that the little heating that we will get tomorrow, limited by windy conditions and clouds, will work to plump up the Cumulonimbus clouds in the frontal band–oh, yeah, there should be some, and that means what?
Graupel (soft hail)! Shafts of them, here and there in the frontal band. The presence of graupel, and it’ll be bashing snowflakes and ice crystals on the way down (the latter can’t get out of the way fast enough) means the clouds will get “plugged in”, electrified, due to those collisions because they generate electricity and lightning is virtually certain in AZ tomorrow. Talk about excitement! Cbs, graupel, lightning, a strong frontal passage, strong winds, and a greater than 100-200 percent chance of measurable rain in Catalina! It doesn’t get better than that!
This pattern also favors better accumulations of precip here with the winds being more southwesterly to west at cloud levels. Amounts? Mod, the very excellent U of AZ mod run indicates Catlania-ites will get around half an inch! I am so excited since this is close to the median amount (0.60 inches) forecast from this microphone two and more days ago! Something must be wrong! Here’s the AZ cumulative precip map for Arizona. Look at all the precip in the State, about an inch and a half of liquid expected on top of Ms. Mt. Lemmon! This is going to be so good for our drought.
Valid for 3 PM AST on the 9th. Most of this falls on the 8th, but passing showers add that bit more into the 9th.
Yesterday’s clouds
They were great, such as they were, and before leaving for NM and points east. Take a look:
6:56 AM. I wanted to hug these little Cirrus uncinus clouds. So cute, just trying like anything to make a little snowstorm to water the ground. Just look at those long tails!
7:47 AM. Then you got to see a Catalina lenticular cloud. How nice was that? Note parhelia on the right.8:04 AM. A nice, patterned Altocumulus perlucidus translucidus.
All in all, I thought it was quite a good day for you. As usual, thinking about others here.
Today’s clouds
Today we’ll likely see some precursor Cirrus, maybe a flake of Cumulus here and there. I will predict more clouds, if necessary, as they occur.
I thought today I would provide some answers to yesterday’s pop “ice-Q” quiz a new expression I just now made up except that I just now also found out that its already “out there” for a computer graphics card and some refrigerators.
But ignoring that fact completely, you might try using it in a sentence today: “My ice-Q level is gradually getting higher these days. I’ve been working on it for some time now.” Lot easier to say than “ice IQ.” Thanks in advance for using “ice-Q” in a sentence today! You’ll have to make it clear that you’re not referring to a graphics enhancing video card or to overclocking a computer and a refrigerator of some kind.
I thought, too, that maybe I need more science content; maybe I’m kidding around too much, teasing you with droll, well, maybe sophomoric humor, and ludicrously WRONG content, like indicating on a diagram that the Equator goes through Hawaii and that the day of the week changes when you cross the Equator. That was so funny! (Or was it?) ((Well, I laughed…)) (((Hmmmmm…maybe a laugh track1would help, like on all those TEEVEE shows that seem to indicate that America has the sense of humor of a moron.))) ((((Is this too strong?))))
So, today I thought I would ramp up the science content, give you something a little heavier to think about, give the old noggin’ some real exercise. Below, from Agee et al. in the February 15 issue of Science just out. I put it in extra big letters so you won’t miss anything:
Its about a bit of Mars found in Morocco at something like the Tucson Gem and Mineral show. If you ever dreamed of being a spaceperson and wanted to go to Mars to see what’s like, you don’t have to go. Some of its already here. Seems the planet was shooting stuff at us, oh, maybe “2.089” billion years ago. Some of Mars is at lot closer than you think, too. Its just over in New Mexico at the UNM Meteoritic Museum in ABQ! How great is that?
Some answers
Below, some of the very SAME photos you saw yesterday with arrows and writing on them. OK, I am repeating things. But you know what, life is a lot easier when you repeat things rather than have to think up new things.
End of answers.
Now I will look at the weather way ahead…
First, I did see a bunch of NOAA tornado watches out associated with our cold trough, now those watches are for central Florida, so it was good to hear that other than a scare, some big ones didn’t occur. You can get all the warnings and watches here, BTW.
Nothing out there, really, for us for two weeks or more. A close call for precip and another cold surge happens around the 9-10th of March, that’s about it.
Oh, me, another LONG dry spell ahead. Are we REALLY going to have a third drier-than-normal late winter and spring in a row? Sure looks like it now with February on line to be just short of an inch compared with our inch and a half average. Dang.
With no weather ahead, will likely hibernate for awhile. Watch some TEEVEE (hahahaha).
AKA, Cumulus humilis virgae, or, with virga. While there were plenty of small Cumulus around yesterday, it wasn’t until after 1 PM that trace amounts of virga could be seen starting to emit from them as they got colder during the day. I think I did, too. By the end of the day, cloud BOTTOMS of those little clouds were about -20 C (-4 F)! Poor guys. Tops were likely only a little cooler, at -22 or -23 C. Those Stratocumulus bottoms topping the mountains in the third photo were about -5 C (23 F) already.
Here’s what happened yesterday. First, the tail of the frontal cloud band came by, dropped a few flakes on the Catalinas before rushing off. Here is that precip, barely detectable on the Tucson radar:
1. 7:43 AM. A haze caused by falling snow tops Samaniego Ridge. Ms.Lemmon is obscured.2. 8:43 AM. The dramatic looking backside of the frontal cloud band (looks like merged different layers of Stratocumulus) closes the book on precip. The lack of precip suggests cloud tops are warmer than -10 C.3. 9:06 AM. Final goodbye. Crenelated tops of castellanus, kind of cute, nice looking I thought. Stratocumulus clouds now top Samaniego Ridge, no precip evident, just cloud bases, but you knew that. I think its great I’ve taught you SO MUCH!4. 12:01 PM. Cumulus fractus amid the dust. Twin Peaks were obscured briefly in dust as the gusty winds developed later in the morning.5. 12:41 PM. Pancakes over the Catalinas, hold the ice.6. 1:16 PM. Then the ice! Can you find it? More educational than “Where’s Waldo”, though both are good for the brain. 15 points.7. 1:24 PM. Some more of that ice. This should be a little easier to find, but not really easy. Remember, ice means precip in these clouds! 15 points.8. 1:31 PM. Its still dusty, windy, I’ve been sitting out in it now for almost 2 h making this ice ID test up. This is the next level of detection. Can you find the ice amid a dusty sky? 10 points.9. 2:12 PM. Another tough one worth 10 points. The Catalinas are still so pretty with those cloud shadows traversing across them.10. 2:42 PM. A lot more ice, but farther away. This was part of a southward moving snow band that dissipated before reaching the Catalinas. 5 points.11. 4:45 PM. Where’s the ice? 1 point.
Extra credit:
What are the concentrations of ice particles in those clouds shown at 1:16 PM through 2:12 PM, photos Nos. 6-9? How about in the last two photos? 25 points.
Answer: Probably less than 5 per liter of those larger than, say, 150 microns in maximum dimension in 6-9, likely 10s per liter in photos Nos. 10-11.
Why know something as arcane as this?
Because it impresses the neighbors, for one thing, because then you can go on and on about the Wegner-Bergeron-Findeisen precipitation mechanism in “mixed phase” clouds, or simply impugn them, with the words from the Walt Disney Studios science song lyric in “Water Cycle Jump1“;
“Your brain is on vacation/if you don’t know about precipitation.”
Second, if you’re into “vigilante science”, as Mr. Cloud Maven person was in parts of his science career, knowing concentrations of ice in clouds by sight will help you clean up some of the messes in the domain of cloud seeding when people report concentrations of ice that are too low. But an extra low ice concentration report benefits them because it helps make the clouds seem like they need some of that seeding to make ice and then more precipitation. Then a big contract is let based on bogus cloud reports, ones that you damn well know are goofy just by looking at the clouds, or checking out rawinsonde cloud tops when its raining from them… I could go on, and on, and on….. Someday…will tell those stories.
I hope that helps explain why this is important. If not, oh well.
The weather way ahead.
Well, you all know about the hot ahead. Now some rain pixels have shown up on March 10th. Not worth showing, but will keep an eye on them.
————
I am euphoric that this song is now online! I loved that song! Gritty but great, except the part where it is asserted that condensation leads to precipitation. Condensation (and the ice form of “deposition”) is only the first step. Also, if you like easy listening, boring music, don’t go to this site; it might be too much for you.
Condensation by itself can NEVER lead to precipitation. You got to have ice or those larger cloud droplets (again, let us call to mind, Hocking, 1959, Jonas and Hocking 1970 was it?) that cloud droplets do not stick together UNLESS they are around 38 um in diameter and larger, and then there have to be quite a lot of those that size and larger to “bump and stick” (sounds like volleyball) to form a true raindrop (mm sizes). You see, cloud droplets pretty much stop growing due to condensation at sizes TOO SMALL to fall out of a cloud as precip! They’d evaporate in the first 50 feet out the cloud bottom. NEVER forget that as a cloud maven junior!
It was hard to see all the smoke around yesterday morning after the two previous stunning days with high visibility. I was thinking I had never seen so much smoke in Catalina as I saw yesterday morning. Here is some photos of that awful event:
7:56 AM. Heavy dark smoke layer evident to SW. Some Stratus clouds also were present.
8:40 AM. Normally, in my experience here, such smoke is husbanded to that region south of Pusch Ridge. But no, not yesterday, its HERE! What an awful view this was!8:45 AM. In this photo not taken while driving1, you can see that there are TWO plumes the lower one drifting south from the area of the Golder Ranch-Sutherland Wash development of expensive custom homes, some of which might have been burning wood for heat, or something else woody, while aloft is a second, separate plume. I could not tell where the higher one came from, even in this time lapse from the U of AZ. Note how in the movie the Stratus clouds in the morning change direction in movement. The movement at first is from the west-northwest (left to right), and those clouds contained the higher smog layer. So, could it have been from PHX??? ———– 1Smokey the Bear reminds drivers that only you can prevent smoky, well, a lot of it anyway.
In the afternoon, the smog was gone, mixed through a greater depth, the layering destroyed by the convection, those rising currents and compensating downward ones, that cream any morning layering. The dilution effect, and it also could have been that the aerosol load (smog) decreased with time, made things look much more clear. To this eye, there was still a lot of smog present, just diluted in the space between the ground and the bases of these small Cumulus clouds shown below. Still, there were so many pretty scenes on this horseback ride with a friend that I took more than 100 photos! Some water was present in some of the little washes, always nice to encounter, and some vividly green spots of of emerging growth (shown last).
The final point worth mentioning for pedantic reasons, is that yesterday afternoon’s TUS sounding indicated the same cloud top temperatures as the day before, about -12 to -13 C. Yet, there was no ice dropping out of those clouds. The day before, with the SAME cloud top temperature, ice and virga were widespread.
What’s up with that?
Ah, the complexities of ice formation in clouds!
When clouds are small and have a lot of droplets per liter in them, likely hundreds of thousands yesterday, given all the smog around, the drops end up being especially small because so many form on some of the smog particles (called “cloud condensation nuclei”).
In repeated flights at the University of Washington, we found that the resistance to form ice is dependent on not just on temperature, once thought to be the sole controller of ice formation, but droplet sizes in clouds as well. Small droplets sizes in clouds meant they were less likely to form ice, given the SAME cloud top temperature. Altocumulus lenticularis clouds are the poster child for ice formation resistance in clouds with their tiny drops, often having to be colder than -30 C before ice forms. On the other hand, clouds in the pristine Arctic around Barrow in the summer time, over the oceans away from continents, and in deep, warm based clouds even polluted ones, form ice at temperatures higher than -10 C when the drops in the clouds are large and have reached precipitation sizes (more than 100 microns in diameter to millimeter sizes).
So, it seems likely that yesterday, our shallower, pollutted clouds had smaller droplets in them than those deeper, less polluted clouds of the prior day in which we saw so much ice form in the later afternoon with about the same cloud top temperatures as yesterday. It is also the case, that when clouds are in large patches as they were the day before, that ice formation has more time to take place, and that, too, may be a factor.
Complicated enough? Yep.
2:52 PM. In the Catalina Mountains on the back from the Deer Camp trail. Cumulus humilis dot skies. No ice evident.
2:18 PM. Cumulus humilis sitting around over Sutherland Heights, and the Oro Valley
The weather ahead
After another round of cold, this one dry cold just ahead for us, the heat is on by early March, and along with that heat in most of the West in early March, likely record cold in portions of the East. Check this 500 mb map out for the afternoon of March 2nd, produced by last night’s WRF-GFS model run at 5 PM AST, rendered by IPS MeteoStar:
Look at the size of that cold trough and low center! Huge!
That isn’t the only weather news ahead, cold in the East, warm in the West in March. Our upcoming cold shock that hits on Sunday, is caused by an unusually powerful upper trough that dips down into Texas after it blows by us, then roars northeastward across the South on Monday and Tuesday. Expect to read about godawful tornadoes in the South on Monday and/or Tuesday.
I wonder if you noticed the blackish smog layer to the south and southwest of Catalina yesterday? Usually it stays down that way, flowing peacefully toward the northwest from Tucson across Marana and Avra Valley, an area where a close meteorologist friend and his wife just bought a house even though they knew this happens in winter and not one in Catalina where we normally escape this characteristic Tucson smog plume. They must like winter smog overhead, but then as the sun heats the ground, it comes down to you. Go figure.
Here is yesterday’s Tucson smog plume exiting Tucson:
8:47 AM. Smog plume exiting Tucson, moving left to right over Twin Peaks area. This was one of the densest, most awful ones I’ve seen from Catalina.
But then, in the later morning hours, a southerly wind brought that smog bank to our normally clear air oasis of Catalina, infecting the shallow Cu fractus clouds that formed as the sun heated the ground. This was a real disappointment since probably most of us were expecting the kind of pristine view of the Catalinas yesterday morning.
10:09 AM. Smoke-filled Cumulus fractus clouds. The smog looks white here instead of dark because of “forward scattering”; the white light of the sun is being scattered in the viewer’s direction by the smoke particles. (In the first photo, there was no forward scattering and so you can see the actual dark hydrocarbony smoke particles for what they are, dark and sooty.
Fortunately the smog was dispersed as the day wore on. As the layer in which it is contained gets deeper, and without more smog being added to it, the amount of smog, say, per cubic mile diminishes and pretty soon it gets so thin you can’t detect it with your eyes. Still, exactly the same amount might be in the column of air between you and the higher cloud bottoms. Here’s what it looked like in the later afternoon:
BTW, while its easy to see that the Cumulus fractus clouds in the second photo are very low, in the 3rd photo above it’s much harder to detect how high these small Cumulus are. The TUS sounding indicated that they topped out at 9,000 feet, or only about the same height as Ms. Mt. Lemmon! Top temperatures in these smoke-filled clouds were no colder than about -8 C (about 20 F), too warm for ice to form in them, especially when the cloud droplets are reduced in size by smog. The larger the cloud droplets, the higher the temperature at which ice begins to form in them, and so smog generally reduces the chance of rain in shallower clouds.
This is why oceanic clouds in pristine regions lacking smog, even shallow ones, rain or drizzle so easily. The cloud droplets are much larger in those clouds right from the get go than those in smoggy regions. So oceanic clouds can rain either because those larger cloud drops reach sizes where they can collide and stick together, forming larger drops that can fall out (“warm rain process”) or form ice at the highest temperatures known for ice formation, -4 to -5 C (23-25 F). Usually both processes are work in those ocean clouds that rain so efficiently. They’re pretty great, really, such little clouds that rain.
Vacation in Hawaii if you’d like to see some up close (though not downwind of the Kilauea volcano plume and in the lee of the Big Island of Hawaii since that volcanic plume can smoke up the clouds real bad there and they stop being so darn efficient as rain producers. Recall that the biggest drop in the world was measured in clouds in Hawaii (1 cm in diameter, Beard, private communication, received AFTER Peter Hobbs and me got the Guinness record for the biggest drop ever measured, 8.6 mm in diameter–got a lotta publicity around the world, too, calls came from everywhere!).
You see, Beard didn’t publish anything about HIS BIG DROP; we published ours in a refereed journal. “Neeny, neeny, neeny”, I think is what you conclude here. Immaturity: sometimes I think its not valued enough in life.
That’s what its like in academia; you publish or die! Die that slow death as an “Assistant Associate” professor of something, never reaching the exalted “Professor” status.
The “combo” ice seen yesterday morning
We had two forms of ice yesterday morning that you may have noticed, say, on your car if it was parked outside overnight. There were originally rain drops left from the storm that froze in place during the cold night (was 30 F here yesterday morning), and then the deposited ice from water vapor on top of the drops.
The deposition process, as we call it, leads to hoar frost ice crystals growing in time as the molecules of water vapor add to it during the night. This combo ice led to an unusual site on the car before the sun did away with it. Here are a couple of shots of this unusual sight:
9:57 AM. “Strange brew.”
9:58 AM.
The weather ahead
After the “sunny malaise” for 5-6 days, with Arizonans statewide out doing things, its back to the Bowl, the trough bowl. The period we’re in now might be called, “a sucker ridge”, a high pressure ridge that is. You might well think, “Well, that’s it for winter in Arizona!” after a few days of the “sunny malaise”, but you’d be WRONG. I can’t emphasize the word, “wrong” enough. The Bowl comes back with a vengeance, too, when it reforms here in the Southwest; there will be one storm and cold blast after another. If you’re a snowbird, you might start to cry, and wonder why you didn’t go to Costa Rica for the winter.
Well, I am looking forward to storms and seeing more scenes of white mountains deep in snow, and green vegetation shooting skyward. That’s the promise of the “Bowl” ahead, where storms collect, in the weeks ahead right into March.
Taking a few days off now, likely without pay, to replenish mind, get out and do things like the rest of Arizonans will. Will give you time to ruminate on all that’s been said here over the past year or so, correct and incorrect, mature and immature…
“Sixteen hundredths”, originally a song by a boy group of that day so long ago, The Crests, about a light rain that fell in May in southern California, an event that is quite rare and exciting at that time of the year there. But then practical and marketing considerations caused the song to be revised to one about candles of all things. How odd. I thought you might like to know some reliable history behind that venerable song, one that made us cry, it was so sweet, and think about, as boys, how much we liked girls when WE were sixteen or so.
Yesterday, while Mr. CMP (“cloud maven person”, but using acronym in trying to be as indirect as possible here) was making some fun of students mixing up units in their calculations of pressure at various heights in the atmosphere, he himself was mixing up cloud “units”, by informing his reader that cumuliform clouds, some dropping graupel, would be seen over Catalina yesterday, not stratiform, sky-covering Altocumulus, followed by great masses of Stratocumulus underneath it, combining later with gray, dank, Altostratus, a scene that finally evolved in the mid-day hours into Nimbostratus with light rain, sometimes with light snow mixed in! Briefly, too, it was ALL “surprise” snow!
The total, 0.16 inches, was also about sixteen times more than CMP thought would fall from that perceived marginal weather producer. (Note: the U of AZ local model’s 11 PM run the night before had it predicted perfectly! However, in some kind of bloated self-evaluation of skill levels, CMP did not consult that model until it was “too late.”) Today, I am quite confident, however, that I really don’t need to look at that model…
What is going on here? Fallibility, I calls it, human fallibility. Remember that old saying about pencils with erasers at the end? So simple and yet, profound.
Oh, well. All’s well that ends well, and the “well” ending was one of a nice little rain mixed with snow (will burn your CMJ tee if you refer to rain mixed with snow as “sleet”!) and beautiful snow down on the Catalinas, so pretty yesterday evening as the clouds lifted.
Today a fine day with small Cumulus clouds, very photogenic again as this kind of wintertime day is here. The mountains should be spectacular, too, due to the cold air that remains that will allow them to be white down low for a few hours this morning.
Precip totals from the U of AZ rainlog.org network here and the national CoCoRahs org here for AZ totals. The measrements at rainlog will indicate that they are for yesterday, the 11th, while the CoCoRahs convention, to assign the rain to the date it was reported, will show the totals for our storm using today’s date, the 12th. You’ll have to wait until about 8-10 AM to get most of the loggers’ reports.
The most I saw in the Pima County gage network was 0.43 inches, an amazing amount, down in Avra Valley. Shocking, really.
BTW, the cloud regime that CMP foresaw for Catalinaland was just to the west of us, around Ajo, AZ, not that far away astronomically speaking. And at sunset yesterday, you could see those Cumulonimbus clouds on the horizon coming into view.
5:53 PM. The forecasted Cumulonimbus clouds for Catalina begin to come into view. I wish I could make this image bigger, maybe in 3-D so you could “feel” this cloud coming at you.
To cry-baby about it a bit more about a missed cloud forecast, this “visible” wavelength satellite image:
1:45 PM AST.
Some un-Cumulus scenes from yesterday:
10:30 AM. Altocumulus perlucidus undulatus and Stratocumulus begin overspreading the sky.11:41 AM. Dark bases of Stratocumulus-Cumulus line up with the wind and head toward Catalina. Virga spews in the distance on the right. Above these clouds was an icy layer of Altostratus.11:58 PM. Mounding tops of Stratocumulus or embedded Cumulus become infected with ice and spew forth virga. Now under this guy, there may well have been a couple of graupel. Above these clouds was an icy layer of Altostratus that helped impregnate the lower Stratocu and Cu with ice, kind of like seeding them.1:17 PM. The lumpy and dark looking bases had disappeared in the virga and snow falling from the thickening Altostratus layer as it became, Nimbostratus. What you’re looking at here is a classic example of snow melting into rain that appears to be the base of the cloud, but its really a transition zone that reveals the snow level.3:14 PM. Snowing hard in Catalina for a few minutes. Here’s what it looks like, coming down at you. Some aggregates of snowflakes were more than an inch across.5:42 PM. The result of our little storm on the Catalina Mountains, Samaniego Ridge.
The weather ahead into March
Gotta ride the storms, ones already predicted as of yesterday here over the latter half of this month. Never good to “yo-yo” on a forecast, as forecasters will tell you.
However, not getting help again in this longer range musing from the NOAA ensembles of spaghetti; site is still down, so riding bareback here so-to-speak, using a western idiom (or is it “idiot”?) In sum, Arizona to end up with above normal precip when whole state considered. This due to being in the bowl, the trough bowl, though breaks in storms, and nice weather, sometimes for several days at a time, will try to fool you into thinking you’re not.
Going farther out on a limb, twig, really, looks like the active storminess will continue well into March. We seem now to have a wet pattern going, though in a desert, its not THAT wet compared to Washington State or elsewhere. Stand by for occasional updates. Am excited for wildflowers now; there may be some!
Its not about car racing…. though that might be more exciting than what I am going to write about. This is a discussion about 500 millibar maps and what you can get out of them.
Here’s this morning’s 5 AM AST 500 millibar pressure map below. Knowing that sea level pressure averages 1013.6 millibars, then 500 millibars, around 18,000 feet or so, is about halfway through, in pressure anyway, ALL the air above us that we have on this planet. Thins out, of course, as you go higher; 10 millibars, for example, is around 120, 000 feet above sea level. You don’t want to be there. Thought I would check around for that height of the 10 millibar level, and here’s what I came across
At this link on the web, however, it is calculated that the 10 millibar level is reached at “5.48 miles” above sea level, and at 4 miles above the sea level, about 21,000 feet, the pressure is but “13.44 mb”! I started laughing because you’d need a space suit to be at the top of our Mt. Lemmon with a vertical pressure distribution like theirs. Yikes! No wonder our math and science scores are behind those in the developed countries!
The pressure at 4 miles above sea level (at 21,000 feet) averages about FOUR HUNDRED FIFTY millibars, not “13”, fer Pete’s Sake, and its still about 320 millibars at the top of Mt. Everest, about 5.5 miles above sea level. I guess these folks don’t do any hiking above about 1,000 feet above sea level. Might be too dangerous without an oxygen bottle in the atmosphere they’re making calculations for. (Looks like someone mixed units; English and metric in their calcs.)1
Now, where was I?
Oh, yeah, this morning’s 500 millibar map… Note where the wind maximum is around a cold trough that is about to pass over us, the one that extends across Utah to Vegas. The peak wind is just about over us, and as the day goes by, it drifts farther south. So what, you say?
Check below where the moisture is at mountain top level, or around 700 millibars, 3 km or about 10,000 feet above sea level.
Valid for 5 AM AST today.Temperatures and moisture at 700 mb, about 10,000 feet above sea level, also for this morning at 5 AM AST. See how the moist air at mountain top level is contained within the wind maximum at 500 millibars. Its just how it is here in the interior of the SW–doesn’t work so well along the coast or north of Salt Lake CIty, UT, or much east of Denver in the wintertime, but it is a pretty solid relationship for hereabouts.
Later today, that green area will be over us and there’ll be some scattered showers. Cloud bases will be high, higher than Mt. Lemmon, and so the precip is going to be pretty marginal. Will be very happy if even a few hundredths of an inch falls in Catalina this afternoon or evening. BTW, with the freezing level so low again this afternoon, soft hail (graupel, tiny snowballs) falling from these clouds is a certainty this afternoon or early this evening. (I’ve repeated some of this in the caption below…. Hmmm. Mind going.)
Here is the latest surface map of obs and infrared satellite imagery on top of the obs from the U of AZ. And, if you look out the window now, adding this at 6:45 AM, you’ll see the first clouds with this trough, likely good enough for a bit of sunrise color here in Catalina.
5 AM AST this morning. Good thing this trough and its minimal amount of moisture is swinging over us in the afternoon since a nightime passage would not have the scattered glaciating Cu and small Cbs we’re going to see later today. And, by the way, the skies should be real pretty, too; big long shafts of virga falling from high based convective clouds. And, as you can see, some jet stream layer clouds–Cirrus, high Altocumulus in advance (near tip of arrow at bottom. Likley another day for lenticular clouds before the cold core gets here. Lots to look forward to today!
What’s ahead? Storms
Storm world, that’s what’s ahead because we’re in the bowl now, the trough bowl, resulting intermittent periods of storminess, broken by deceptively nice weather for several days; the latter, times of some trough fakery, one that make you think the “bowl” is gone. But then its BACK! So, don’t be afraid when the weather turns nice again after today.
Here is a sequence of maps from IPS MeteoStar ones that document what I am trying so poorly to explain, the overall spell of storms that we’re in, where one cold trough after another is drawn to Arizona like metal filings to a magnet. First the “interruptus”, now on deck, a map for about five days from now. For some reason, I put all of what it means in the caption.
Valid Saturday, February 16th at 11 AM AST. No trough nowhere near Arizona. In fact, it looks like the trough bowl might be relocating to the Ohio Valley down to Natchez, MS. This is pure trough “trickeration”, the latter a term used in football for trick plays where somebody looks like they’re going to do one thing and then they do something entirely different. So at this time here in Arizona, you’re thinking, “la-dee-dah, no more storms, just nice weather now for quite a while”, and at the same time reading about bad storms and cold in the eastern US. But you’d be so WRONG, as we like say around here. Look at that trough coming into the Pac NW. Guess where its headed? By the time that one gets here, you’ll realize that you went for the “fake”, and that all is not well weatherwise in Arizona, and more troughs after that one piles on top Arizona, bringing bountiful late winter rains, one after another. Finally, you go back to Michigan, you can’t take it any more, because you only came here for the good weather, not to stay and be one of us for the whole year….Valid for 5 PM AST, the 20th of February. Now look who’s bowlling! Its Arizona! Lot of great rain foretold with this one.Valid for 5 AM AST, Sunday, February 24th. More rain on the doorstep.Valid for 5 PM AST, Tuesday, February 26th. The grandaddy, the Big Bopper, a crescendo of troughy-ness occurs.
In conclusion, and remembering that these exact depictions above are not going to be realized as such, they will vary in intensities and positioning; nevertheless, the prediction from this keyboard is that February 2013 will have ABOVE NORMAL precip in just about all of Arizona due to storms that occur in the last 15 days. I am really happy for you, and its always great to conclude things like this, conclusions that bring so much happiness to others.
The End
————————
Mr. CMP, in a twinge of conscience, realizes that the error he goes on about today is one that he himself would like have made during his struggles in math and physics in HS and college.
It seems we’re heading into another “trough bowl”, a persistent collection area for cold air in the upper levels over us during the next couple of weeks. In the meantime, something about today’s great weather, if you like a little drama.
Underview
The wind starts blowing pretty hard later on this morning or certainly by mid-afternoon. As it gets gusty and dramatic, its only natural for our heads to start swiveling around, looking skyward, knowing something ominous is happening; something’s changing drastically, like the barometer. That gut reaction comes not from the gut, as popular lore would have it, but from the deep responses to fear located in the amygdala, that ancient piece of brain that knows scary things1. And it would be right.
Here is the scary stuff that going to happen, first from the NWS, as told in their latest (as of 4:30 AM) very “Special Weather Statement“, FYI. Have goose bumps now!
Also shown at that link is a “Special Statement” from the Albuquerque office of the NWS, one in that I particularly liked because of their use in their own Special Statement of the word, “potent” to describe this incoming storm. Its a great word to employ, and apt in this case; and its a word that conveys power. A “potent” this or that is something tremendous! “Po-tent”; fun word to say, too. Think, too, of the devastation when just two little letters are prefixed to that word.
Today is the precursor day for our “potent” storm, a day with potent winds, likely reaching 40 mph in momentary “puff gusts” (lasting just a second or two) here in Catalina, especially in the hills overlooking our little berg. The air gets squeezed against the Catalinas today as it races northward into a large Great Basin low center. Should be gusty here right up to when the potent cold front hits tomorrow morning. When that front hits, we should see light to moderate rain for a couple of hours, along with our usual temperature drop of about 15-20 degrees in an hour, too. And, as it always does, the wind will drop off dramatically, turning to the northwest for awhile before returning from the southwest.
BTW, since we haven’t had strong winds in so long a time, there will likely be more dust raised today and tonight than would normally be the case. Also, you tend to see more branches break off trees after a long non-windy period such as we have had.
All the mod outputs I’ve seen from overnight (3, USA, Canadian, and the downscaled U of AZ one) have rain here tomorrow morning followed by the chance of a passing, brief shower in the afternoon. Those passing shower clouds would be Cumulus congestus converting to small Cumulonimbus clouds. Very pretty to see in the winter.
The chance of measurable rain here in Catalina tomorrow?
Oh, 100%. We don’t mess around here; but then we don’t have any particular responsibility to anyone either.
Amounts?
U of AZ mod has us on the edge of the 0.25 inches region, slightly less than was forecast yesterday at this time. SOP from this keyboard: minimum 0.08 inches, maximum 0.38 inches, middle ground, 0.23 inches, same forecast as yesterday. However, as a person who suffers from a desert version of precipophilia, I love it when its MORE than I think it could possibly be. (Didn’t really have this syndrome in Seattle…)
Rain chance here HAS to be near 100% due to our position near the Catalinas, and how those frontal band clouds will be fattening up as they approach them, especially to the point tops are fattened up to BEGIN raining in the trailing part of the frontal band (requires the formation of ice up there, as you know). The trailing parts of storm bands is where we in Catalina Census Designated Place pick up an additional amount of rain over outlying areas in fronts like the one coming tomorrow.
So, in sum, tomorrow will be a fun day and a dramatic one with rain pounding down in the early morning, and, with the snow level plummeting to below 3500 feet during the rainy part of the storm, and a scenic one when the leftover, non-raining Stratocumulus clouds begin to break open, build into scattered Cumulus and small Cumulonimbus clouds. Those snow covered mountains will come fully into view. So, a VERY photogenic day ahead tomorrow, particularly in the afternoon. Charging camera batteries now.
Today’s clouds
First, as we saw at sunset yesterday, Cirrus clouds, lots of different varieties/species today, probably including the patchy thick versions with shading called Cirrus spissatus. Most likely these clouds will thicken enough in coverage to be termed, Altostratus, widespread gray looking ice clouds. Below those, maybe a brief Cirrocumulus or maybe an Altocumulus lenticularis–again, look to the northeast of the Catalinas for that. These latter clouds can have the best, really delicate patterns embedded in them on days like this. But, they may only last minutes if they form.
Our high cloud spawning grounds have been doing their work overnight, as you will see in this infrared satellite loop from the University of Arizona. You will see that high clouds have spawned from clear air in the lee of both the mountains of southern California and those in northern Baja California. Those cloud spawning zones have quit for the most part now as the air dries out aloft over them, but the shield of clouds they launched now extends over the middle of Arizona, some are over us now, too, so a good chance of some sun rise color. That nice plume of ice clouds launched by those mountains is wrapping around our coming upper level low center as it marches down the California coast.
As you know, those high clouds are “decorations” in a sense because they will have nothing to do with the surge of lower clouds and rain that blasts into Catalina tomorrow morning. But they do present us with the chance of great sunrise and sunset color. Just now I saw that the U of A model foretells drying at Cirrus levels over us near sunset today, meaning that the huge clear slot that (oddly) precedes storms so many times, may arrive just as those Cirrus/Altostratus clouds depart around sunset. Hope so.
The weather ahead and far ahead (beyond 10 days)
This is great news and not so great news (if you’re snowbirding in Arizona); the coming rejuvenation of winter. The mod output from last night’s 5 PM AST global data crunch (can be seen here) has a series of troughs of cold air dropping southward from the Pac NW into the Southwest US, meaning multiple chances for rain, but even if no precip, lower than normal temperatures. In other words, it appears that we are entering another spell where we are in a trough bowl, a nesting place of sorts for cold air aloft and the storms that come with them.
Below, from our TUS NWS, is an example of what it means to be a thermometer going in and out of “trough bowls”, that region where one or more upper level troughs find us for a couple of days or more, this graph for January. You can see that if you were a thermometer, it would be like being in the ocean with big swells driving you up and down, up and down. That’s what’s ahead now, that same temperature roller coaster we saw in January appears to be ahead for us through the remainder of February.
Temperature roller coaster due to sporadic positioning of “trough bowls” in the SW US.
But, with troughs come chances to joyfully fill our February rain gauges and see our desert vegetation spring to life. So, really, snowbirds aside, its all good.
Would refer you to our venerable error-filled NOAA ensembles of spaghetti plots to support or weaken these longer term conclusions, but I haven’t been able to get in, seems site must be down.
—————-
1May be some kind of “first” here, seeing the word amygdala in a weather briefing. Tell your friends.
Let’s look at February’s climo for Catalina, now that the month is practically half over (hahahah, sort of):
Oh, my, such a sad chart so far….What the experts at NOAA’s Climate Prediction Center are thinking–a smudge of higher precipitation for Arizona, thought the chances, they feel, aren’t great, 30-40 % is all. Still, its something. This would be a pattern of precip that goes with our upcoming storm, one that will be much more of a dumpster in the northern half of the State than here. With the spaghetti plots having already indicated a high probability of a big trough in the SW US a week ago, this forecast may be based only on that one pretty sure thing which would give a monthly prediction of above normal in the Four Corners area and northern Arizona a leg up, so to speak. I mean, you wouldn’t want to forecast below normal precip in a region for a whole month if you knew there was going to be a flood in the first two days of that month! Hope this forecast is due to more than our Cold Slam, coming up!
BTW, yesterday I discovered at first sunlight that a trace of rain HAD fallen the previous night by finding raindrop images in the dust on my “trace detector” instrument (a car parked outside under the open sky). Hope you found drop images somewhere, too, and properly reported or at least, logged, your trace of rain.
Here’s a radar depiction of those areas of sprinkles from WSI Intellicast, amounts ending at 5 AM AST yesterday. If you are in one of the faintly blue areas shown below, and DID NOT report a trace, we will have to consider confiscating your Cloud Maven Junior tee….and you should consider whether being a CMJ is really for you. Its OK if its too much…
Here the rain forecast from the WRF-GFS model, our best, as rendered by IPS MeteoStar:
Valid for 11 AM February 10th. This is the first WRF-GFS run with rain here in it. Only the Canadian model had rain here before this one.
Yesterday’s news, of course, and a surprising development “locally” where measurable rain during the day seemed remote, at least at 6 AM yesterday. But, a blob of rain moved in around noon and gave out 0.06 inches. We’ll take it.
And as you all know, much more rain from our tropical system off Baja is just ahead, U of AZ mod says beginning late tonight and continuing into most of tomorrow morning as you can see here. If you want to see the forecast rain/snow in all of Arizona pile up over time, go here (from the U of AZ). The model is thinking between 0.25 and 0.50 inches here, an inch or so on top of Ms Mt Lemmon. Gut feeling is that we’ll see more than half an inch here from this, with a good chance that it will go beyond noon tomorrow when the mod thinks its all over. Hoping, anyway.
Below, amounts forecast by the U of AZ model ending at noon tomorrow. The model was run on data from last night at 11 PM AST.
Also yesterday, we had a very brief but fabulous sunrise “bloom” illuminating the bottoms of the thick Altocumulus clouds overhead. It looked something like this1: Hoping for same today.
7:23 AM. Year different from 2013.
In case you missed it, here’s what gray skies and light rain look like, falling of course, from that great steady rainmaker, Nimbostratus.
12:31 PM. “Two riders were approaching (under Nimbostratus), and the wind began to howl…”2 Well, OK, one rider. Note rain haze against Pusch Ridge and smoothness of sky due to precipitation fallout that obscures cloud detail. When you saw that smooth sky approaching from the SW, that was the time to turn your horse around and head for the barn, as here.
The rest of yesterday? Blasé. Steady diet of overcast Stratocumulus/Altocumulus clouds sometimes with splotches of virga, and a sprinkle here and there. Here’s pretty much what the rest of the day looked like:
2:01 PM. Two layers of Altocumulus are visible, the lower one on the S horizon beyond Pusch Ridge. Cloud detail (rumples and such) shows that there was no precipitation falling from these clouds. If someone asked you why, you’d say that the layer was not cold enough to produce ice crystals-snowflakes, things that would grow and drop out the bottom. The cloud droplets in these clouds are too small to fall, and even if they did float down and out, they’d be gone in a few seconds because they are so small.
4:46 PM. Creamy-looking Stratocumulus. Sometimes cloud bottoms look this way because of a moist layer overrunning dry and stable air, air that “raggifies” cloud bottoms and wind shear at cloud bottom can produce concave (inverted bowl-looking bases). TUS sounding at 5 PM shows air speed sped up a little at cloud base over wind just below them and wind direction turned about 10 deg from that just below cloud base. Was it enough? I guess so, but not really sure except by sky.
Rain still foretold for Sunday night into Monday morning, followed by a cold blast, but amounts have been on the decline. Could be just a few hundredths to a quarter inch is about all this one can produce.
Clouds today
More interesting scenes today of “multiple layers” as we would call them, and not as widespread as yesterday overall; Altocumulus (and with the wind picking up aloft, a lenticular here and there–look to the NE of Ms. Mt. Lemmon) Altostratus, Cirrus. And, with luck, a great sunset.
Way ahead…….
In the usual model vagaries, absent rain in them after this Monday for awhile, rain has shown up, beginning on the 4th of February. This is a new development in the models for that period. The NOAA spaghetti plots give this system pretty good support–that is, something is likely to approach the central and southern California coast a day or two before our possible “storm” on the 5th. but thereafter, not much confidence for a storm here. So, likely to be on the doorstep for us on Feb 3rd or so as it. Interestingly, it rains for two days off and on here, Feb. 4th and 5th, and the rain follows a trajectory from the Pacific much like we have today, which is always a good sign since the atmosphere likes to repeat itself. You can see the full sequence here.
TE
——————————-
1A replica of yesterday’s sunrise since Mr. Cloud-maven person’s camera failed to ingest a memory card prior to a dozen or so snappages. Camera acted like there was nothing wrong!
2That Dylan line would been that bit better, more dramatic, with “Nimbostratus” in it.
(From Dylan’s, “All along the Watchtower”, the best version, it goes without saying, performed by Seattle’s own Jimi Hendrix.)
