Flash: Plethora of storms lining up for Catalina during the rest of December. Spring wildflower seeds take note. Expecting to see a little snow here, too, in one of those–happens about once a year at our elevation (3,000 to 3500 feet), btw, so its not terribly unusual.)
The first one, on December 12th, is in the bag, the one we’ve talked about for a few months I think (that forecast based on spaghetti), except now it happens on the 13th. Droughty Cal will get slammed by this one, too.
Hope you’re happy now.
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Now, for the “main event,” a recapitulation yesterday’s clouds….
A Nice,cool and gray day it was, if you like sky-covering layers of Altostratus translucidus and opacus , interrupted in the mid-day hours by a lower layer of Altocumulus clouds.
Those Altocumulus clouds represented a “thin” corridor of clouds between deeper bands that went over us yesterday. Bands of thicker and thinner clouds are pretty normal as storms pass by us. First, this overview from satellite of our cloud sequence:
Visible satellite image for 1:15 PM yesterday when Altocumulus clouds comprised the main deck, rather than Altostratus. Too bad there was more humidity underneath this system,; coulda been a great rain. The arrow points to our location and the thinner cloud corridor that pass over at that time. Cloud banding like this always occurs with storms, providing lighter and heavier periods of rain over an hour or two.
From the beginning, these for your edification:
9:29 AM. Classic icy Altostratus translucidus. No droplet clouds evident. Hope you logged that remark. Estimated height above ground? 22, 000 feet at this time, somewhat lower than the balloon sounding indicated at 5 AM AST. Stuff lowers with time as storms approach.
11:29 AM. Big virga (falling snow) from Altostratus opacus (sun’s possible is not detectable at this time) rolls in from the horizon. Lots of weak radar echoes beginning to show up in our area. Some lower flakes of Altocumulus clouds can be seen at left center, and on the horizon, left center. Bases now around 18,000-20, 000 feet above the ground. Likely a few drops were reaching the ground where the virga hangs down another few thousand feet. Freezing level was around 11,000 feet above sea level.1:40 PM. Thin spot in satellite image, characterized by Altocumulus opacus clouds, was now passing over us between bands of heavy Altostratus with virga. As a CMJ, the appropriate thing to say to your neighbor would have been, “Wow (lot of excitement here), what happened to those deep clouds?! Cloud tops have really come down. Must be a thin spot. Hope that darkness on the horizon is another deep cloud band because then it might rain.” End of excitement. Cloud bases as you would guess, have continued to lower (but not nearly as much as the tops did). The Altocumulus bases here are estimated to be 12,000 feet above the ground. (By the end of the day, they were about 9, 000 feet above the ground, 12,000 feet above sea level).
3:05 PM. That last banded feature in the sat image, consisting of Altostratus opacus again, is starting to pass overhead. More weak radar echoes were present, some passing overhead, but, saw no evidence of a single drop on trace detector (car parked out in the open, moved for that purpose, since CM can’t be outside at all times.3:06 PM. Most of you will share my excitement here; surely a drop will be felt at any moment! As you know, in these situations, the rain hits the ground (largest drops first) long after the preciping part of the cloud has passed overhead. So, here we are looking downwind over the Charoulou Gap at a bunch of virga that passed over a few minutes ago, hoping for that drop that never came.5:01 PM. As the deep cloud tops moved away, and a large clearing approached from the west, the setting sun provided a golden view of Samaniego Ridge. The lower-topped Altocumulus clouds can be seen above Sam Ridge. Bases were now down to 9,000 feet above the ground. Tops were about 16, 000 ASL, about -13 C. Higher colder tops were still in the area producing virga.
5:03 PM. Even the teddy bear cholla, as horrible as it is, can be quite gorgeous in the evening light.5:19 PM. Later, sunset occurred, pretty much on time. It was OK. These, of course, are those Altocumulus clouds, sans virga; too warm in this case for ice production even with tops around -13 C, or about 9 F. Ice formation characteristics can vary from day to day, the reason is not always clear, but seems to be most closely related to the sizes of the cloud droplets. The bigger they are, the higher the temperature at which they freeze.
Below, from Intellicast, folks who hate Accuweather, where our radar network thought it rained a few drops on you (or probably just above you) yesterday:
Radar-derived precipitation for the 24 h ending at 5 AM AST this morning. Note dry slot over Catalina.
There was quite an astrological event yesterday, hope you caught it. Only lasted a minute or two as a comet, or a gigantic piece of space debris, or maybe that asteroid that astronomers said was going to hit earth, an event usurped on the Seattle Times front page (!) by a Washington Husky basketball victory over the ranked Xavier U team1 blazed across the sky.
Happened to walk out side just as it appeared in the sky and became very afraid at first glance, but had enough presence of mind to take a couple of quick shots for posterity in the seconds before possible death as we all do these days no matter how bad things are for us at the time since we have our smart phones with us, and why not? Might go viral and we’ll be famous at last!
I was thinking there would be this gigantic, cataclysmic explosion like the one that ended dinosaur life on earth 65 million years ago any moment. But, then nothing happened and I realized I had been fooled by a parhelia (sun dog or mock sun) with a strong radial-like portion! How funny izzat? Here are more images of those things.
In case you missed it, or also got very afraid for a moment, likely as early peoples and their astrologers would have, likely interpreting the phenomenon as a sign from the gods to sacrifice someone for a great crop or hunting season, here it is:
2:56 PM. Rare comet or gigantic space debris sighting during the daylight hours.2:56 PM. Zooming in closerAlso 2:56 PM. You can see really how hot it is on the front end as it races across the sky and into the earth’s atmosphere!
The weather?
Oh, yeah. Well first of all, it did rain during the Big Game in Santa Clara last night, as forecast here, and just about everywhere else as well, as many of you likely saw. While its true that rain falls on the rich and the poor alike; the good and the evil as well, it only rained Duck touchdowns on the Arizona fubball team last night.
How sad was that?
Was figuring an AZCat victory over The Duck would be the same as a Washington Husky one since we beat down the AZCats in every way imagineable except for the score when we (the former company team) played them a few weeks ago2.
Oh, yeah, the weather HERE….
Overcast pretty much the whole day in the State Winter Cloud of Arizona, Altostratus–get a lot of that here as storms sideswipe the area. As you know, Altostratus is a deep mostly or all ice cloud with tops nearly always up near where Cirrus clouds are.
Why, if its so friggin’ deep, you ask, is the optical depth nearly always less than FOUR? (I can feel your anger). Of course, more than FOUR would mean the sun’s position is not discernible; its just gray up there. Well, my friend, its because Altostratus is mostly composed of ice crystals, not very high concentrations of them, typically a few to tens per liter, as contained in a volume of air in one of those today’s “Coke Tastes Great!”) liter bottles. Those low concentrations let a lot of the sun’s light through even though the clouds are 2-3 km thick. Really not much to As clouds if you’re flying in them, kind of like being in an extremely light snowstorm. So, we can see where the sun is. When the sun is gone, they”re likely more than a few km thick, maybe 4-6 km, since eventually even low concentrations of ice crystals won’t let the position of the sun be seen.
You can expect those thickest As clouds today at times.
Altocumulus clouds, all or mostly droplet clouds are surely going to show up, too, as the moist layers lower into temperatures that are too warm for all ice clouds.
Since droplets are 10 to 1000 times more numerous in clouds than ice crystals, and droplet clouds reflect more sunlight off their tops, a much thinner droplet can obscure the sun’s globe and look darker on the bottom than a much deeper ice cloud. In techno-speak, create its much easier for a droplet cloud to be associated with an optical depth of 4 or more– a great piece of information to pass along to your neighbors as a CMJ; do it in a casual way, it’ll be more impressive that way.
Since the 500 mb jet stream is passing south of us today, still looking for a few sprinkles or R– somewhere later this morning or in the afternoon around these parts.
The End, and its really enough! Yikes. Storms still dead ahead in the remainder of December!
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1From the Seattle Times this classic front page on, The Importance of Asteroids Hitting Earth and Husky Basketball:
From 1997. Yeah, we save stuff.
2Like all great former employees, I continue to root for the company team, even though have developed an AZCat partiality, as well.
WHAT a come-through, drought-denting rain that was yesterday to interrupt our Oct 19 through Dec 4 dry spell! Take that, rainless November, you disappoint you!
No one expected so much, not even our best models. In fact, the great U of AZ mod, if you can remember as far back as yesterday at this time and that you ALSO stopped in here, it had a measly 0.10 to 0.25 inches here, with just 0.50 and 1 inch prediction for the Catalinas–have to look real hard at yesterday’s precip map. Usually these models overpredict the precip some, too.
Here’s your Pima County ALERT gauge 24 h totals as of 2:30 PM yesterday , though the rain fell mostly in the 12 h ending at this time1:
Gauge
15
1
3
6
24
Name
Location
ID#
minutes
hour
hours
hours
hours
—-
—-
—-
—-
—-
—-
—————–
———————
Catalina A
rea
1010
0
0
0.12
0.47
0.83
Golder Ranch
Horseshoe Bend Rd in Saddlebrooke
1020
0
0
0.35
0.79
1.81
Oracle Ranger Stati
approximately 0.5 mi SW of Oracle
1040
0
0
0.28
0.75
1.10
Dodge Tank
Edwin Rd 1.3 mi E of Lago Del Oro Parkway
1050
0
0
0.28
0.67
1.10
Cherry Spring
approximately 1.5 mi W of Charouleau Gap
1060
0
0.04
0.55
1.06
1.77
Pig Spring
approximately 1.1 mi NE of Charouleau Gap
1070
0
0
0.31
0.75
1.10
Cargodera Canyon
NE corner of Catalina State Park
1080
0
0.04
0.28
0.75
1.22
CDO @ Rancho Solano
Cañada Del Oro Wash NE of Saddlebrooke
1100
0
0
0.16
0.47
0.63
CDO @ Golder Rd
Cañada Del Oro Wash at Golder Ranch Rd
Santa Cata
lina Mountai
ns
1030
0
0.08
0.55
0.94
1.77
Oracle Ridge
Oracle Ridge, approximately 1.5 mi N of Rice Peak
1090
0
0.04
0.59
1.65
2.87
Mt. Lemmon
Mount Lemmon
1110
0
0.04
0.47
0.91
1.46
CDO @ Coronado Camp
Cañada Del Oro Wash 0.3 mi S of Coronado Camp
1130
0
0.04
0.71
1.46
2.72
Samaniego Peak
Samaniego Peak on Samaniego Ridge
1140
0
0.08
0.63
1.14
1.73
Dan Saddle
Dan Saddle on Oracle Ridge
2150
0
0
0.16
0.75
1.57
White Tail
Catalina Hwy 0.8 mi W of Palisade Ranger Station
2280
0
0
0.08
0.24
0.31
Green Mountain
Green Mountain
2290
0
0.04
0.16
0.55
0.94
Marshall Gulch
Sabino Creek 0.6 mi SSE of Marshall Gulch
Below, the view of our storm during its peak if you had been flying on a commercial satellite, say, from Honolulu to Washington, DC:
Annotated visible satellite image excerpt for late yesterday morning during the heavier parts of our storm. This image from the University of Washington Huskies Weather Department, and let us not forget that except for clock mismanagement2 in the waning two minutes combined with and an unfortunate fumble that Arizona would NOT be playing in the Big Game in rainy Santa Clara, CA, today since the Huskies had won that game in every way but the score, the latter being the unfair way to get a win when you’ve really been beaten down. But, that having been said, let us forget our differences and root for whichever team wins! A front from the Pacific is scheduled to move over the players during the game and so, like Napoleon’s ill-advised invasion of Russia, weather may make a huge contribution to history today as it did back then. Recall that extreme cold and lack of preparedness led to the loss of almost all of Napoleon’s invading army in 1812; those poor guys.
Analysis of the 500 mb height contours and wind field from IPS MeteoStar for 5 AM AST just after rains began. Jet max at this level had already spurted inland and south of Tucson by this time. Upward motion is best ahead of the bend in the winds around Baja on this map, AND under and north of the strongest winds at THIS level in just about all of the INTERIOR of the SW and into some of the western high Plains, like Denver. This relationship disappears completely for the eastern US. In fact, almost no precip of any magnitude falls within the 500 mb jet core back East, just the opposite of here because the major rains and precip back there occur in the warm, moist air rushing northward and rising due to that warmth ahead of fronts and low pressure centers from the Gulf of Mexico.7:48 AM. Looking ESE at the Samaniego Ridge and the Catalina Mountains from Sutherland Heights near Equestrian Trail Road. Weather, for people who text: 1 R-F; R- OCNLY R. (Visibility 1 in light rain and fog, light rain occasionally moderate rain, the latter falling at a rate of 0.1 to 0.3 inches per hour. This photo valid until about 1:30 PM yesterday.
9:41 AM. Dogs assess rain intensity and indication of flooding before deciding if they will venture out. “Rain: it doesn’t just affect people.”
1:44 PM. Looking west, signs that the storm is about to end or has ended already. Such signs are marked by huge blue regions in the upwind direction.
1:51 PM. Blue palo verde enjoys a raindrop on a twig, that drop essentially a fish eye lens since the reflection in it is of the mostly blue sky that was moving in at this time.1:46 PM. Laddled with drops, even the teddy bear cholla, the worst plant known to man, but when covered with snow is called an “Arizona Christmas tree” had a particular beauty right after the rains ended.
Close up view…. This is about as bad as a plant can get.
3:44 PM. What spectacularly blue skies and unlimited visibility the day finished with after such a satisfying rain. Good to be alive still!
The weather just ahead….
Another lower latitude wave is progressing toward Arizona as we speak. That wave and its front will likely drench the AZCats in their championship quest this evening. And, the southern part of wave is again juicy with a ton of middle and high clouds. Those clouds start passing over us today, starting, of course, with the highest, thinnest ones, Cirrus, and, as per usual, the level of moisture will lower as time goes on. The wave (the bend in the winds aloft) passes over us during the day tomorrow, and again, the wind maximum at 500 mb will be south of us. It is a necessary, but not always sufficient condition for almost all of our winter rains. Just looking at the upper level map makes me think some rain here overnight or tomorrow. No model run, as of 11 PM AST, that I have seen has rain here overnight or tomorrow, but I would watch out for a little rain anyway during that “window.” Cloudwise, lots of Cirrus today, lowering to Altostratus with Altocumulus by tomorrow, lots of virga around by tomorrow and likely sprinkles or light measurable rain around.
Farther ahead….
Several rain chances are building up, the first one looking better all the time for the 12th, something that has been pretty confidently suggested in the “spaghetti plots3” for more than ten days. Spaghettis is suggesting lots of trough action over the next two weeks. The individual details will vary in the model outputs, some will have rain here, some won’t for the same day, but the weather pattern will be, “unsettled”; lots of trough actions, lot of clouds coming and going like today and tomorrow, no unusual warmth since “Mr. Troughy” (aka, the trough bowl) will be the dominant weather personage for us over this two week period. Lots of great sunrises and sunsets guaranteed, no long boring clear spells.
Pretty darn excited about the weather promise ahead!
2Even a weatherman knows clock mismanagement when he sees it.
3Don’t forget those great, “I heart spaghetti” tee shirts with those colorful spaghetti displays on them! They make fabulous Christmas gifts for those discerning weather friends of yours; sophisticated, too. Most people won’t get it. Yours today for just $19.95, plus $43 dollars shipping. Order now!
Here’s your cloud day for yesterday, a fairly complex day for your cloud diary entries:
7:27 AM. Looking SW along Equestrian Trail Road; Altocu with Cirrostratus above.7:45 AM. Altocumulus perlucidus over the Catalinas.12:38 PM. Stratocu begin to move in under the Altocumulus layer.2:47 PM. Altocumulus lenticularis began appearing, suggesting strengthening winds aloft. This was an odd location for such clouds, perhaps responding to uplift ahead of the Catalinas. Haven’t looked at Froude or Richardson numbers, though, to see if this is reasonable hand-waving.3:02 PM. Looking NNW at Stratocu (“the boring”; is State Cloud of Washington, and Oregon, for that matter) with a little Altocu on top.
4:33 PM. Stratocu. Kind of characterized the dull, dark, late afternoon and evening hours.
Intermittent R- to R– expected during the day today. Hoping for a quarter inch (forecast to friends early yesterday morning, 0.225 inches; will be ecstatic if more falls. Latest AZ mod has about that amount here, and over half an inch in the Catalinas. Usually, though, those amounts are on the high side. On the other hand, if the details about where the the rain band shown below are off a bit, we could do far better than the 0.10 to 0.25 inches predicted. Here’s the accumulated precip predicted for today from that model:
Accumulated rain until 10 PM AST tonight from the U of AZ model run at 11 PM AST, the latest. Much needed, nice heavy band of rain across AZ!
Next rain threat continues for the 12th, plus or minus a day.
Of course, only CLOUDS can rain, so the title is a little silly, but it sounded more dramatic like that. This is the first measurable rain, it fell between 9 and 10 PM here, in EIGHT weeks!
And you could sure smell that special fragrance from the ground and desert vegetation as soon as you stepped outside to do your exercises this morning!
Nice sunrise yesterday morning to start the day. In case you missed, of course, I am there for you.
BTW, in the captions below, I have included for you a discussion of climate issues in a kind of stream-of-consciousness format. OK, its a rant that came upon me out of the blue. CM sometimes gets mad and loses control for a few seconds; need to get some counseling maybe…
6:56 AM. Altocumulus perlucidus. Say no more. Might be a lenticular sort of on the right. Not the classic almond shape, but it did hang on for a long time in that spot. Say no more.
Kind of gray after that in Altostratus with an undercutting, lower layer of Altocumulus by mid-afternoon darkening the sky up some more. Some virga here and there with sprinkles-its-not-drizzle reaching the ground by late afternoon in the Catalina area. Here is your cloudscape for later in the day, very Seattle like during approaching storms that actually rain lightly on you for hours:
10:35 AM. Classic Altostratus translucidus, ice path in cloud all the way to the sun.10:39 AM, after walk down a slope to give YOU a view to the southwest, classic Altostratus as seen when not looking toward the sun. Hard to tell if its translucidus or opacus looking this way. By the way, even when you can see the sun, As clouds are thousands of feet thick, tops usually at Cirrus clouds levels.1:26 PM. Here come the lower, flocculent masses of Altocumulus clouds, ones composed of droplets.3:15 PM. It was all downhill for cloud bottoms after the Altocumulus moved in. Now, the bottoms are lumpy and much larger, casting them as Stratocumulus. There was some virga and very light rainshowers reaching the ground at this time, too. A few drops fell at 3:11 PM. Only the great cloud mavens of all time would have noticed. Lasted maybe one minute.3:15 PM again. Lot going on here, so I thought I would point out some things on a gray day, in particular for my fellow meteorologist Mark A at the U of WA who winters in the Tuscon smog plume. Mark is a super sleuth when it comes to snowpacks, but maybe doesn’t have so much moxie when it comes to smog. Mark, as you know may now, was fired as Assist State Climo for Washington when he demonstrated and kept complaining, along with two faculty members, that the claims of gigantic snowpack losses due to global warming (now repackaged as “climate change1“) in the Cascade Mountains were hugely exaggerated, likely the result of cherry picking a cold snowy beginning and ending with a run of El Nino winters, ones that lead to less snowpack in the Cascades of Washington and Oregon. Such cherry-picking led to a wonderful suggestion of huge declines that has led to a bounty of funding and continued employment, promotions, accolades, citations by Big Media, etc, because such claims, even if exaggerated and untrue, are what we want to hear! And, no one ever got a job for claiming they can’t find any sign of global warming, or only a little one, but rather are vilified for even suggesting exaggerations in the “global warming” domain. Mark, BTW, continuing his sleuthing has recently shown that similar claims for declines in snowpacks in Montana near Glacier National Park, have not been decreasing but rather increasing. He’ll get HELL for this one! So, more vilification is likely ahead for poor Mark, as well as more smog.
What’s ahead, besides the Big Pac 12 Fubball Game on Friday evening?
More clouds. Maybe a few more sprinkles especially tomorrow after dawn. See nice map below from the U of WA Dept of Atmospheric Meteorology (original colors on the map below by that big troublemaker, Mark Albright)
Valid for 8 AM AST, tomorrow morning, which is Thursday, in case you’ve lost count of the days of the week. The arrow denotes an upper level trough, or bend in the winds. Ahead of the bend (sometimes referred to as vorticity, or curling air, or red curly air) the air tends to rise producing cloud sheets, whereas behind red curly air, the air descends. See Seymour Hess, Introduction to Theoretical Meteorology, 1959, Florida State University Press. As you can see by the arrow, that slight bend in the winds is about to pass over your house in Catalina, and the U of Az model output from last evening sees a little rain here with that passage. Yay! Also note suggestion of bifurcated jet flow with a minor maximum in wind (slight bunching of contours) to the south of us, nearly always required for rain here in the cool season.
Beginning to wonder, with all the middle cloud thickness out there over and SW of Baja that’s headed this way if we won’t get sprinkles that produce a little measurable rain later today or overnight….
7 AM AST. Look at all those clouds over Baja and to the west of there.You can see this whole loop from the Washington Huskies here.
Models beginning to wetten things up here as well, like that Enviro Can model that sees our tropical surge high and middle clouds passing over us now, as deep enough for measurable rain later today and overnight. Huh. U of AZ mod, the best one for us, is still dry around here except on mountain tops. Our larger scale model, however, also has some very light rain in this area now, later today into tomorrow morning.
What’s intriguing is that a little jet core at 500 mb (up there at about the height of middle clouds) passes south of us as this happens, key for precip here1 in the cool season. The major jet stream is far to the north.
As you know, we have a bit of an El Niño going, both a “Classic Niño” as well as the “New Niño” going, and El Niños strengthen the southern portions of jet streams in the very way that we’re seeing in this situation.
They do that because its warmer than usual in the central and far eastern Pacific tropics due to heat in extra big Cumulus and Cumulonimbus clouds that pump away down there over that extra warm water, and that rising warmth produces a greater than usual difference in temperatures throughout the troposphere between the tropics and the mid-latitudes. Since jet streams are the products of temperature differences between warm and cold air around the globe, so unusually deep warmth in the tropical eastern Pacific gives a little strength tweak to jet streams coming into the coast2.
SInce there are two of these lower latitude “waves” traveling along in the southern branch of the jet stream, there are TWO chances for slight rains including that for later today. The next one barges in on the 6th of December. Will again be dense middle and high clouds with virga at its worst, like this one, though again a hundredth or two could happen.
Next real rain chance, and major front passage with air that’s too cold for us, will be on the 12th. Spaghetti folk, or “Spaghetti Busters”, those who can make sense of these balls of yarn, can EASILY see that trough on the 12th and a cold front with are “in the bag” even though that’s ten days away. Rain occurrence is more dubious, since the trough may land a bit too far east to produce rain, only a lowering of temperatures. Here is that plot from last evening. Enjoy.
Valid at 5 PM, December 12th. Pretty clear a nice trough will be in the area then.
Your yesterday’s clouds
11:44 AM. Up and down, up and down, those wavy air motions that produced this interesting line.3:37 PM. Classic Altostratus translucidus (sun’s position is visible).5:20 PM. Sunset Altostratus (ice clouds) and Altocumulus (droplet clouds).
BTW, for horsey people, the Cement Trough had water in it yesterday after being completely dry ten days ago:
11:44 AM. At the Cement Trough headed to South Gate.
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1See Rangno, 1973, unpublished manuscript and figures for the whole US using only the horizontal shear in jet stream at 500 mb as a definer of precip occurrences. Its really quite something, though, I guess you can’t see it.
2This was figured out by the Great Jacob Bjerknes of the Norwegian School of Meteorology while he was cruising into retirement (“Emeritus” status) at UCLA in the 1960s, though Chuck Pyke3,4, his grad student, did most of the work. Did a lotta work on the big “Classic” El Niño of 1957-58, which, per chance turned out to be an International Geophysical Year with a lot of extra observations! How lucky wazzat?
3Chuck, as you may recall was in the National Guard whilst at UCLA and was sent to Biloxi, MS, for two weeks of training and while there, was “gifted” with the passage of the eye of Hurricane Camille, one of the strongest of the century. Later the remnants of Camille, to go on and on, produced 31 inches of rain in 6 h in Virginia.
4Chuck P, who now lives in Arizona, also was very thorough in his evaluations of rainfall in his other studies concerning the seasonal timing of rainfall throughout the West. He once told me when I visited UCLA once to get Bjerknes autograph5 that he had gone to every rainfall measuring site in his study! Now some people go to every baseball park in America, but going every rain gauge site would be more interesting to cloud mavens. He further told me he found one that had not moved for 30 years, but the rainfall had been decreasing. When he went to that gauge, he found that it was being overgrown by a tree! This is why you have to check things.
5I failed. He was “Emeritus”; too good to be in his office that day. You see, your Catalina cloud maven was a strange person even then, wanting an autobgraph by Bjerknes rather than one by Mickey Mantle, though one by Mickey M would be worth a lot more today.
(Formerly titled: “Storms lining up for Catalina in early December”)
Things change.
Confidence was never real great in the spaghetti plots we rely on for hints about the reliability of our longest range “wishcasts,” as a friend puts it. Now it seems we’ll only see high (Cirrus) and middle (Alftocumulus and Altostratus) clouds on the edges of the rain areas that move across California, maybe the NW corner of Arizona, too, during the first week in December. Oh, I suppose there could be some virga with a sprinkle here from the thickest of those middle clouds, but that’s about it now.
But, on the happy side, we’ll see our usual array of stunning sunrises and sunsets under warm conditions when those high and middle clouds begin arriving about Saturday, the envy of many northern “climers”, or “northlats” this time of year. (Starting to see those Illinois, Minnesota, Ohio, license plates now, aren’t we?)
Our next chance at rain after that is not good but revovles, and the air does, around a cutoff low that gets stuck out of the mainstream here in the SW in mid-December. Those, unless you’re in the exact right position, or are gigantic like that one back in ’67, often have limited amounts of moisture. If you’ve never seen a cut off low, here’s what they look like in the middle troposphere, a forecast valid for this Monday afternoon:
From the University of Washington Huskies Weather Department, this example of a cut off low at 500 millybars, or around 18,000 feet above sea level. They kind of meander around not doing much, then eventually dissipates/”opens up” into just a bend in the winds up there, as this one does as it begins to move eastward and then northeastward (the killer for us) as it comes into the Cal coast. Most of the jet stream, as indicated by numbers of contours, is far to the north, something that allows lows like this to pretty much have a mind of their own for awhile. The bulging northward contours over us mean that it will be toasty and dry here, maybe some Cirrus clouds around..
So, it would kind of lucky for us to get something out of it. And, when you’re in a droughty period, as we have been in for the past EIGHT weeks, things like that don’t usually work out in your favor. Its like being a football team that loses the close ones but also gets blown out in other games. Since we’re talking about sports now, a pause for a sports exultation: Washington1 volleyball somehow beat No. 1 Stanford on Wednesday!
Special Scientist, Bob Maddox, who is an actual expert and does a superb weather blog for this area, has passed me a long range forecast from the CPC (Climate Prediction Center) recently that I will share with my reader:
A wet mid-winter in the Tucson area been forecast!
How wet? 2 inches in December, 4 inches in January, and a colossal 6 inches in February. Wow. There would certainly be flooding at some point later in this period.
These results derive from a longer range forecast model the CPC runs. Although the fantasy factor is high here, still, something to hope about. With a bit of an El Niño in progress, and this forecast resembling the tendency for El Niños to act up in aiding wetness in the Great Southwest in the mid-winter to spring, there is some SLIGHT credibility here.
Too, such forecast amounts resemble the great El Niño winter of 1992-93 that helped ruin the Biosphere 2 experiment, then in progress because there were too many clouds and not enough sunshine to make it “work.” Imagine.
OK, already getting too worked up about this. Will quit here.
The End
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1The writer was employed in studies of clouds by the University of Washington’s Cloud and Aerosol Group, and quickly adopted the company teams as his own, one of the signs of a great employee, one who wore Washington this or that sports Tees in the off hours, no doubt helping to enhance Washington revenue streams.
I wanted to add some suspense to this blog today, and to enhance readership beyond one, I would do like TEEVEE news and weathercasters do who get people to hang around by saying silly things like:
“Will it rain for the Arizona fubball game tomorrow? We’ll tell you at 11”
when an answer consisting of a single word would do.
These are one of the dumbest, outrageous and annoying lines that weather and newscasters come up with over and over again, and I hope I am NEVER on TEEVEE and have to say something like that unless I am making a LOT of money, and then I might say almost anything! (Haha, just kidding, I think, but not positive.)
Valid for 5 PM AST Thursday, December 4th. The location of Arizona and Catalina on a map of the United States is shown. Areas of rain are generously pointed out by arrows to help the reader comprehend this map.
Well, since the supercomputer calculations, these based on earth data from last night at 5 PM AST (00 Zulu, Greenwich Time, Central Universal Time, etc.) continues to show early December rains in Catalina (see illustrative figure above), we need to have some spaghetti to see if a trough in the middle troposphere has much chance of being here:
Also “valid” for 5 PM AST, Thursday, December 4th, corresponding to the storm map above from NOAA, and also based on earth data from last evening at 5 PM AST. Areas of high confidence and cluelessness are pointed out, FYI. The yellow lines are what the model actually predicted. (Hint: doesn’t match up that well with itty-bitty error-laden runs, one that try to account for “chaos” in the atmosphere (where itty-bitty things like a single thunderstorm mislocated in the initial run can cause the forecast to go bad; and, of course, real errors in measurements. Sometimes this strange plot, deemed a major advance in weather forecasting, is called by CM, anyway, a Lorenz Plot, after E. N. Lorenz who liked to publish papers on chaos. OK, as you can see, I hope, not a lot of confidence is suggested for a storm on December 4th at this time; mods will continue to see it come and go. Here, you will only see those forecasts that have a storm for Catalina.
Went on a hike yesterday morning, about 4 h worth up the Baby Jesus trail to the Deer Camp trail and back down again. Here are some scenes from later November from a desert having a lot of rain in September and October. Octotilloes are blooming here and there! Amazing! Morning glories hanging on, too. Cement trough, though, was dry. Boohoo. Didn’t expect that.
Ocotillo in bloom, November 22nd, 2014.Arizona fall color as evidenced in a coral bean bush.More Arizona fall color in something, maybe a wild cotton bush. Was hiking with the Cottons, too.Some kind of green grass. Most of the grasses, though, were dried up.Morning glories still abound!Typical riparian scene seen on the hike. Crossed this wash several times, and all of the views were as good as this.A weed. Burrowweed in bloom. Kind of pretty, I thought, but who cares what I think?Expected to see water here at the old “Cement Trough” where water is often counted on by horsemen and horsewomen.People from all over gather at the Cement Trough scenic area for a hike respite.Two stage arrowhead.
6:52 AM. Altocumulus cloudlets over and east of the Catalinas.6:52 AM. Sprinting to the other side of the house, this spectacular scene of virga falling from Altostratus. Breathtaking!6:53 AM. To the NW, the virga roiled downward into mammatus bulges under lit by the sun.6:54 AM. The color was fading just in a minute or two, but it was still a breathtaking panorama I thought you should see.
Some additional commentary about these scenes. One of the remarkable things about clouds, a real unknown, is how clouds such as Altocumulus (1st photo) can get so cold, colder than it was this mid-November in Wyoming, and can remain all or mostly water drops, which is what you are looking at in those cloudlets over and beyond the Catalinas. Pretty amazing. This phenomenon has been known about for decades, but not fully explained. We expect to see a lot of ice in clouds with tops colder than -30 C (-22 F) as you might imagine.
Here’s the sounding near the time of these photos, with writing on it:
———-Begin learning module———————————-
The Tucson balloon sounding, launched around 3:30 AM AST yesterday morning.
As a CMJ, you need to be armed with explanations if, on a morning walk, your neighbor, at first overwhelmed by the morning beauty, but then instead of being quiet, goes on to ask, “Hey, aren’t those clouds composed of droplets; they must be pretty low and warm?”
Since you’ve already seen the TUS sounding for the hours just before this, you know those cloud bottoms are real cold and high, -26 C, and 19,000 feet above you here in Catalina, and tops are really cold, about -32 C (-26 F), you cringe. What to say? How do you explain clouds that can sit there at -32 C and develop little or no ice, while knowing that Cumulus clouds, ones whose tops have never been colder than -7 C, can be completely composed of ice just after reaching up to that temperature?
—————-End of learning module, such as it was———————
Here’s another example from yesterday of extremely cold clouds with few ice crystals:
9:36 AM. Altocumulus perlucidus opacus (sun’s position is not detectable). The TUS sounding for the morning would not be valid at this time since the cloud bases were slowly lowering but they would still be about -20 C at this time, height about 17,000 feet above ground level. And, at this temperature, such clouds are ultraripe for ice production by aircraft that may flay threw them. See next photo for a POSSIBLE aircraft production of ice in these cold clouds.
10:43 AM. Of course, all of you were looking for some aircraft perturbation I’m sure, and this seemed “too linear, too uniform, the crystals too small (as deduced by the sloping lines of virga underneath this line for the ice to be natural. No other virga looked like this having straight fine lines underneath, the thing typical of contrails. However, its not the typical ice canal, either, with clearings beginning on the sides. In fact, the cloud seems thicker here where an aircraft may have traversed it, posing an explanatory challenge. Also counter to reason, why would an aircraft fly so far in what would have been light rime icing conditions in those Altocumulus clouds? Lots of questions, no really good answers.
11:07 AM. Linear feature passes over Catalinaland. Was hoping for a drop so I could claim it had rained in November, even if it had been a phony rain.
11:32 AM. Looks phony to me! Not a real cloud. I think we’re looking now at the tube of high concentrations tiny ice crystals that slowly settled out from that Altocumulus layer after an aircraft went through it–this tube to me appears to be BELOW the general layer, due to settling out after a few larger ice crystals fell out first. Am about 60 % sure that’s what happened and caused that linear feature. Getting pretty worked up about, too.
Well, Shakespeare said it: “Much ado about nothing,” so it must be important if he said it.
Had some really nice cloud scenes after the big clearing came through in mid-afternoon:
3:38 PM. Our typical spectacular lighting on the Catalinas scenes as storms move away.
4:49 PM. A dramatic finish to the day; light showers hit south and southwest of Tucson, but faded before arriving here.
There were some light showers that produced as much as 0.20 inches of rain in the south and east parts of Tucson late yesterday afternoon and evening. Nice for them.
The weather way ahead
Nothing in the way of rain in the immediate future. Have to wait until December for any real chances. See this bad boy for December 6-7th, this panel only 360 h from now1!
Valid at 11 PM AST December 6th. Note that the heaviest rain in Arizona is over Catalina! These are totals that accumulated in the 12 h prior to 11 PM AST. Hope I made you that bit happier showing you this. It’s a pretty cold system, too, might be a close call for snow here.
The End.
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1360 h in advance, even using our best model, is about in time like the distance to Betelgeuse in light years. Hence, caution when the writer says, “only.”
Started out clear yesterday. Below, an example of that completely clear sky in case you missed it.
10:06 AM. Clear skies are evident as we look in the general direction of Baja California. HOWEVER, note shallow smog plume exiting Tucson and flows northwestward across Continental Ranch over there by Twin Peaks where fellow University of Washington meteorologist, Mark Albright, lives.
I think it is interesting that Mark would chose to live as a snowbird in a smog plume rather than here in Catalina where that Tucson smog plume rarely strikes. Its pretty regular down there because the normal morning wind in Tucson is from the southeast and that wind shoves the urban smog over to Mark’s house on many cold mornings. Pretty funny, really.
Yesterday’s clouds
In the mid-afternoon, a stream of patchy Cirrus was beginning to creep over us. If you don’t believe me, you can see it in the University of Arizona time lapse film for yesterday.
And, in those leading Cirrus clouds were some spectacular, stupefying really, complex patterns of cloud formation and and holes in them, ones like CM had never seen before except maybe that one time in Durango back in the 1970s. Here are some examples of those odd that were up there:
3:14 PM overview of Cirrocumulus and Cirrus clouds with oddities.3:14 PM Close up of previous cloud scene. Note all the weird stuff going on.3:22 PM. More oddities. Going crazy trying to understand what the HECK is going on!3:23 PM. Close up of rectangular “fringe.”
Started to breath a sigh of relief when this melange of complexity moved off rapidly worrying that someone might call and ask me to explain it. So, when some Cirrus uncinus and/or the rarely seen Cirrus castellanus came by I started to relax, feel confident again. Here are some of those pretty shots of little, icy clouds trailing light snow showers, likely, to repeat again, crystals called bullet rosettes. The ones in the part of the cloud from which they spew are likely tiny prisms, side planes, and tiny solid columns, thick, but tiny hexagonal plates with little fall speed, so those hang up there, while the favored ones in the best tiny updrafts in these clouds that resemble tiny glacial Cumulus clouds grow from those kind germ crystals into bullet rosettes, complicated crystals with multiple tiny columns sticking out of them. If you would like to read all about the crystals that form in high icy clouds like these you should spend some time browsing this paper, co-authored by the great John Hallett1 I really like footnotes–yes, of the Hallett and Mossop riming and splintering mechanism, discovered by them in 1974. Helped explain why there was a LOT of extra ice in clouds that shouldn’t have it.
Here’s one more weird scene in Cirrus before moving on to something explicable:
3:43 PM. Holes, plops of downward moving air amid the Cirrus/Cirrocumulus. But why so round?
Thankfully, here’s what transpired next at Cirrus levels:
4:02 PM. Cirrus uncinus (one with tufts or hooks at the top and long streamers of ice below them) followed the strangely patterned sky.4:03 PM. Look at all the larger ice crystals pouring out these little guys! Its amazing. Notice how FINE those strands are. Airborne work we did indicated that the cores were only a 5-20 meters wide!4:20 PM. Reminded me of a ballet the way the clouds and the streamers were arranged around one another.4:17 PM. Just a little before the dancing clouds came by, there toward the Gap was this CIrrus castellanus mimicry of a full grown Cumulonimbus capillatus (tuft in center of photo). Look, it even has a tiny anvil spreading out, to use the word “tiny” for the 18th time! How fun was that to see!
Of course, with all the patchy Cirrus around we were guaranteed a nice sunset and it did not disappoint:
5:29 PM. Sunset.
Today’s clouds
Heavy ice clouds, several kilometers thick at times. We call that kind of fray, often full sky-covering layer, Altostratus. Likely some Altocu around, too. Will look now and see if I see any of those latter ones. Oops, too dark.
With clouds kilometers thick, tops at Cirrus levels, you can expect to see virga, and the chance of a few “sprinkles-its-not-drizzle” later in the day. The whole progression of clouds can be seen from the U of AZ model output from last night in these forecast soundings for Tucson. As per usual, the bottoms get lower and lower as the day goes by, but are still up around 13, 000 feet above Catalina by around sunset. So, will be tough to get a drop to the ground before then. U of AZ mod thinks all measurable rain will be to the south of us. Oh, me.
BTW, and this is an embarrassment, it was asserted by this keyboard that rain would fall in November at the outset of the month. This is the last chance for that! Egad. But forgetting that possible gaffe, moving ahead anyway to what’s going to happen in December (of this year).
The storms way ahead, that is, ones in early December.
Those early December storms for us are coming and going in the WRF-GFS runs. But I am counting on rain here in early December myself due to an interpretation of those weird in so many ways, “spaghetti plots.” I think they’re showing, and continue to do so, significant troughs coming through the Southwest in early December.
The End
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1Later after the referenced paper above, and this is quite interesting, the great Hallett was to claim that me and Pete Hobbs had embarrassed2 the entire field of airborne researchers due to a paper published by us way back in 1983 (J. Hallett, 2008, communicated by him during his presentation at the Pete Hobbs Symposium Day of the American Meteorological Society, New Orleans.
2But it was a good embarrassment, not a bad one due to incompetence, I think.
