The first of a couple of patches of rain over the next 36 h are passing through now, R at this second, 4:40:32 AM, and 0.09 inches of rain so far. Nice.
And with the last troughy coming across tomorrow during the day, with another chance of light rain then, too. Looks like we’ll easily go over 2 inches for the month of December (1.94 inches now), the first above normal in rainfall winter month since November a year ago.
Yesterday’s clouds and flowers
Not as widespread or dense as expected in the afternoon, but prettier, which helps counteract error. Let us begin our review of clouds with some paper flowers; there are still some blooms out there! Amazing.
8:25 AM. Seen on a dog walk under overcast Altostratus. Desert marigolds still going strong.8:38 AM. Classic Altostratus, some virga apparent below darkest part. Saguaro cactus is extruding slowly from the ground on the right. Need time lapse to really see it do anything.11:17 AM. Deeper clouds have moved away and now comes lower, shallow Altocumulus clouds some spewing virga. Photo annotated for Mark Albright, University of Washington research meteorologist who lives in Continental Ranch, and thus in the Tucson morning smog tide.
3:27 PM. One of the prettiest scenes of the afternoon, this array of Altocumulus.
3:27 PM also. Only the extra special Mark IV cloud maven personage would have caught this aircraft ice trail, originally within those lower Altocumulus clouds, much too warm for normal contrails. This is probably around 30 min old.
5:12 PM. Sunset in leading bank of clouds that led to the light rain this morning.
The weather way ahead
Threat of a larvae killing cold wave later this month fading; looks like that cold air will end up in the eastern US now, and no further precip after the series this week. Darn.
Check these out in yesterday’s “Olympics of optics” where all kinds of goofy optical things were seen:
3:19 PM. Fireball crosses Tucson skies leaving long plume of “smoke.” Photo not touched up in any way shape or form because that would be wrong. Note: always carry your camera with you since you only have seconds to capture something like this.3:19 PM Fireball crosses Tucson skies 2.
3:57 PM. Then there was this “wrong way1” partial halo a few minutes later. Could it be another sign of climate change, as almost everything that happens is? The sun is below the bottom of the photo; haloes are supposed to go around the sun not around nothing. When a partial halo around nothing occurs like this, its called a “circumzenithal arc” caused by tiny, pristine ice crystals like hexagonal plates. If you want to read about optics of all kinds, go to the University of Washington Huskies weather department where they have optics chapter online.
4:10 PM. Contrail passes through or above Cirrus uncinus. Yesterday was one of the top (worst) days for contrails above and in view of Catalina IMO. Note lines of contrails above and behind weather station. We hope it was due to an unusual confluence of conditions such aircraft flying a heights different from normal due to a peculiar wind profile, Cirrus moisture at the level of the airways, that kind of thing since we rarely see as many as yesterday.
Today’s clouds
Thickening and lowering, ho hum, the usual as a trough aloft (bend in the jet stream winds up there) off southern Cal and Baja approaches today. Ahead of the bend in the winds, seen in the map below, the vast layers of air rise ever so gradually, something like cm per second. But, its enough to produce sheets of clouds.
What kind of clouds?
Heavy, dense and gray ice clouds we call Altostratus (As), with thicker and thinner spots should dominate the day. Then as the moist layer lowers, that is, as the As “bases”, really just comprised of falling snow that only looks like a solid bottom, get lower, patches of virga will start to reach the ground later today. Altocumulus ought to be around, too, water droplet clouds not cold enough to be completely iced up. Expecting those layer clouds, or undercutting layers to be low and lumpy enough to be termed Stratocumulus late in the day.
Rain?
The strongest winds at 500 mb (around 18,000 feet above sea level) will be to our south beginning today, a necessary condition for virtually ALL wintertime rain here. CM is expecting some rain to fall in Catalina later today, or tonight as this bend in the winds aloft goes by. Expected amounts in this first wave, trace, minimum to 0.25 inches max by mid-day tomorrow.
Its really dicey situation since its not clear how deep the moisture is off Baja now, but looks potent enough for as much as a quarter inch from this keyboard, though less is more likely. Sorry the range is necessarily so great.
BTW, the WRF-GOOFUS model didn’t have ANY rain predicted for this time frame period in both of the 5 AM AST and 5 PM runs of yesterday. So, we’re out on a bit of a limb.
After tommorow….
After 5 PM AST tomorrow, all peoples and models see more rain for Catalina as two waves/troughs barrel in right behind the first one that goes over tonight. The 2nd and 3rd ones produce a couple of rains through Thursday with big breaks likely in between.
The total amounts for Catalina between now and Friday morning still look like they will be contained within the range of 0.25 inches (things don’t go so well; disappointing really) and an inch (things go really well). Best guess is average of those, for a few day total of 0.625 inches.
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1Remember “Wrong Way Corrigan”? Picked up that fumble and scored a TD for the other team? Maybe it was an early sign of the effects of concussions in fubball.
Due to some kind of server meltdown, the NOAA spaghetti plots, better, “Lorenz plots” in honor of “Dr. Chaos”, Edward N. Lorenz, the ones my fans1 like so much, have not been available.
But they’re back today!
But what are they telling us? Gander this for Christmas Day:
Valid at 5 PM AST Christmas Day, December 25th. I’ve annotated it especially for you. The view is one where your looking down at where Santa lives from a big tower. Not all annotations are accurate.
Don’t need to tell you that the weather looks like there’s a good chance of cold and threatening weather for Christmas Day. Big trough implanting itself in the West around then. Maybe those easterners who hogged all the cold air last winter will share some of it this winter. The warmth we had last winter made it bad for horsey with all the fly larvae that survived.
Kind of bored now with the rain immeidately ahead, but only because everybody else is talking about it, too. Its no fun when you don’t have a scoop and you’re just saying things that other people are already saying. Even my brother in North Carolina, who knows nothing about weather, told ME that it was going to rain here on Thursday! How lame is that? Of course, it is true that you won’t here anywhere else that the chance of measurable rain is more than 100% this week in Catalina ; at least I still have that. Tell your friends.
When does it fall? Sometime, maybe multiple times, between Tuesday afternoon and Friday morning. Hahaha, sort of.
Looks like the first trough and weather system will go over on Tuesday through Wednesday, chances of rain then, and yet another colder one on Wednesday night into Thursday. So, 100% chance of measurable rain falling sometime between Tuesday afternoon and Friday morning, probably in several periods of rain. Look for a frosty Lemmon Friday morning.
Predicted amounts from this keyboard? Think the bottom of this several day period of individual rain events will be only a quarter of an inch. Top, could be an inch, if everything falls into place. Canadian mod from 5 PM AST global data yesterday, for now has dried up one of the storms, that on Thursday, the day the USA! model thinks is our best chance for good rains based on the virtually same global data! Of note, the USA model based on 11 PM AST data, has begun to lessen our Thursday storm that bit.
This is the reason that the certainty of measurable rain here in Catalina is spread over such a several day period.
Your cloud day yesterday
Just various forms of Cirrus, most seemingly from old contrails that produced exceptional parhelias (sun dogs, mock suns).
Very contrail-ee sunset, too, as contrail lines advanced from the west. They were likely more than an hour old when they passed over Catalina yesterday.
10:56 AM. Glistening rocks after the rain. Very nice. Cu fractus at moutain tops.
2:36 PM. Nice example of the rare seen Cirrostratus fibratus (has lines in it). Hope you logged it.
3:42 PM. Looks like old contrails to this old eye, resembling CIrrus radiatus. The “radiating” aspect may be due to perspective.
3:50 PM. Parhelia lights up in CIrrus. These, due to the high speed of Cirrus movement, only last seconds in thin streamers like these. To get really spectacular optics the crystals up there have to be especially simple, like plates and stubby columns, maybe prisms as well. When aircraft create contrails, there is an excess of ice crystals, far more than occur in natural Cirrus as a rule, and due to that high concentration, can’t grow much and usually stay as simple crystals, not develop complicated forms like bullet rosettes, crystals with stems sticking out every which way.5:23 PM. Contrail-ee sunset. Pretty, but awful at the same time, since it shows how the natural sky can be impacted by us in our modern lives. You wonder how much of us the earth can take?
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1Why just recently C-M had a comment from a fan in Lebanon3, that country near Israel, not the one in Ohio2! Said it was warm there now, but normally it rains for days at time in the winter, and gets real cold. You see, the eastern Mediterranean is, climatologically speaking, a trough bowl. Troughs just hang out there a lot, creating something called the “Cypress Low.” Though it only rains in the cool season, October through May, as in Israel, places in Lebanon get 25 -40 inches of rain during that time, and its exciting rain because it almost all falls from Cumulonimbus clouds, many with lightning! C-M is getting pretty excited, since he’s on record as wanting to go Lebanon to study the clouds there! See Lingua Franca article from 1997! He loves those Mediterranean wintertime Cu. Hell, you probably threw it out, so here it is: Lingua Franca _1997. See last sentence. last page. Thanks.
2Speaking of Ohio, who can forget that great 1980s rant against urban sprawl in Ohio by Chrissie Hinds and the Pretenders! Will it happen to Catalina after the road project? An insurance agent told me that Catalina was to be absorbed by Oro Valley after it was completed. Oro Valley says they know nothing about that.
Yesterday’s cold front packed a few more rain “calories” than expected…. Kind of wrecked my play on beer in yesterday’s blog title as a way of making fun of it, you know, “Front light”. See rain amounts below.
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But before that, a heads up: 1) More rain on way next week, at least a 100% chance of measurable rain during the week, and more storms after that (people will be complaining before long);
2) there are some pretty cloud photos at the very bottom in case you’d like to skip over a lotta verbiage; quite dull writing, hand-waving, that kind of thing about what happened yesterday.
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Personal weather station totals as of 2 PM AST yesterday as rain ended from the Weather Underground map. The green and yellow areas are radar echoes, yellow the stronger ones.
The official totals are pretty amazing, too, considering our best model was predicting something like 0.01 to 0.10 inches here in Catalina just before the rain started1. Note below the 2.20 inches at Mt. Lemmon. BTW, we’re now just about at our average rainfall total for December here in Catalina of 1.86 inches and we’ve gotten 1.85 inches so far.
Here’s a truncated rain table for our area from the Pima ALERT gauges (its a rolling archive and so you’d better get there early if you want to see the full lineup of totals for yesterday’s storm):
Pima County Regional Flood Control District ALERT System: Precipitation Report Precipitation Report for the following time periods ending at: 04:14:00 12/14/14 (data updated every 15 minutes) Data is preliminary and unedited. —- indicates missing data Gauge 15 1 3 6 24 Name Location ID# minutes hour hours hours hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.00 0.00 0.00 0.00 0.51 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.00 0.00 0.00 0.00 0.55 Oracle Ranger Stati approximately 0.5 mi SW of Oracle 1040 0.00 0.00 0.00 0.00 0.63 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.00 0.00 0.00 0.00 0.55 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.00 0.00 0.00 0.00 0.75 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 0.00 0.00 0.00 0.00 0.67 Cargodera Canyon NE corner of Catalina State Park 1080 0.00 0.00 0.00 0.00 0.59 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke 1100 0.00 0.00 0.00 0.00 0.43 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains 1030 0.00 0.00 0.00 0.00 0.47 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak 1090 0.00 0.00 0.00 0.00 2.20 Mt. Lemmon Mount Lemmon 1110 0.00 0.00 0.00 0.00 0.55 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp 1130 0.00 0.00 0.00 0.00 0.79 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.00 0.00 0.00 0.00 0.71 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.00 0.00 0.00 0.00 1.34 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station 2280 0.00 0.00 0.00 0.00 0.59 Green Mountain Green Mountain 2290 0.00 0.00 0.00 0.00 0.98 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Hell, there wasn’t any rain in the cloud band west of us when I got up, and so I thought with some lifting, and that jet core at 500 mb slipping southward from southern Cal as the day went on, rain would develop farther south in the frontal cloud band. It did, of course, but still thought it would blow through in 2 h or so, something akin to the models as well. The rain fell for about 5 and half hours! The clearing took place a little before sunset, not in the early afternoon as expected.
So what happened?
I think you and I overlooked a disturbance aloft behind the frontal band. It was sliding SEwd fast from Nevada, catching up to our little frontal band. When those things happen, clouds magically seem to be appearing on the backside of the frontal band, fattening it up, holding its progress back; and the rain areas get bigger. The frontal band was MUCH fatter when it went by TUS than it had been just a 100 or so miles to the west at 4 AM AST yesterday morning. Here are contrasting satellite and radar images for two periods yesterday, before the band fattened up and the second, when it was raining so much here:
Satellite and radar imagery for 4:30 AM yesterday. Sneaky backside disturbance is represented by those clouds near Vegas. No rain echoes west of Catalina, stop along the Pima County line making it look like rain will be marginal here.BY 1:30 PM in this satellite image with radar, the band is twice as wide and there’s rain almost all the way down to Mexico way. Look how those clouds and showers near Vegas have caught up with our front, almost attaching themselves to it in north central Arizona. Lots of times this process of upper air disturbances catching up to a front generates a cyclone along the front as the front widens and begins to kink. I think that’s what happened anyway. Whatever. It was a great confluence of events for us here in Catalina. Think how the wildflower seeds are feeling right now with already an average amount of rain for December, and its not half over, and more is on the way, yay!
If you’re a true C-M disciple you noticed something else yesterday: true DRIZZLE in the rain. Drizzle may be even more rare than snow here. And the thick low visibility rain consisting of smallish drops from drizzle sizes, 200-500 microns (a couple to a few human hairs in diameter) and raindrops just above those sizes for much of the time the rain fell, should have made you start thinking of a warm rain process day. Maybe there was no bright band in the radar imagery during those times, something that happens when rain is ONLY formed by colliding drops that get big enough to fall out; no ice nowhere. In the heavier rains, sometimes when visibility was improved, ice was very likely involved.
The TUS sounding really can’t shed light on this question since the morning was had shallow clouds that weren’t raining yet, tops barely below freezing, and the 5 PM AST sounding, with tops at -10 C (14 F), was a little too late, though that layer that was sampled did produce what appeared to be ice virga in the direction of TUS about the time of the sounding. BTW, its well known that “warm” rain processes that don’t involve ice occur at temperatures below freezing, so the expression is a bit of an oxymoron.
So, without radar imagery over us during the time of the thick rain and drizzle, we can’t say for sure, but it sure looked like it to C-M, which is what you should think as well I think. Thanks in advance for thinking what I think.
Enough of my excuses2, let’s rock and roll with yesterday’s clouds
Your cloud day
7:35 AM. Light rain, looking suspiciously like “warm” rain, clouds not looking so deep, spreads over the Catalinas. Its only gonna get better from here as frontal band leading edge is just across the street over there on the Tortolitas.
8:09 AM. “Oh, what a crummy front, things breaking up already”, you were thinking. Also, “Look at how shallow those clouds are! Terrible.” Sometimes these brief thin spots or clearings are called, “sucker holes.” Hope you didn’t fall for it like I did. (Just kidding.)9:43 AM. W0X1/2 R–F (text for “indefinite ceiling, zero, sky obscured, visibility 1/2 statute mile in very light rain and fog”), rain has piled up to 0.10 inches by this time. But you notice there’s something different about the rain; , its thicker, small thick drops hardly making a splash in puddles, even drizzle drops in it. You begin ask, “Could this be a solely warm rain event?” I think so. Note disappearing telephone poles.12:46 PM. After several hours of rain, flood waters begin to appear. Note mottled surface of this small rain-formed lake, showing that the drops were making good splashes at this time. Rain intensity deemed R (moderate) then. Deemed not a warm process rain at this time due to those drop sizes and less bunching, fewer small drops in between the larger ones, visibility was about 2 miles in rain.
The best scenes of all were when the clouds began to part in the late afternoon and evening sun. I hope you caught these beautiful scenes:
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—————————————————– 1Total rain prediction from our best model, the one from the U of AZ with the predicted totals through 3 PM AST yesterday. The model run was at 11 PM AST the evening just before the rain began:
The arrow points to our location, in which only a tiny amount of rain was predicted. Mod doesn’t miss very often by this much, but the earlier December storm had the same mod problem, too little in the model compared to what actually fell here. Gee, new thought… Could it be a poor representation of the warm rain process? Hmmmm.
2Your Catalina C-M did have a correct range of amounts that could fall in yesterday’s storm right up until the last minute. For weeks he was predicting, and staying firm with, 0.15 inches on the bottom, and a voluptuous, if that’s the right word, 0.80 inches potential on the top.
Front will roar across like a mouse, not a lion, as hoped for a few days ago. Not too many rain “calories” in it. Measurable rain will still occur, starting sometime between 9 AM and 10 AM AST–oops. raining now at 7:10 AM! Check out U of AZ model for rain timing. First drops fall here in that model output (from 11 PM AST last night), between 8 AM and 9 AM. The frontal band, such as it is, is almost here! However, the model rain tends to arrive a little fast here, though not always. FYI, be on guard.
C-M is holding firm with a minimum of 0.15 inches today, but previous foretold possible top of 0.80 inches a few days ago is out of the question. Will be happy with 0.25 inches at my house. Since I am also measuring the rain as well as forecasting it, I have a feeling things will turn out fine.
There will be a nice temperature drop, windshift, and simultaneous rise in pressure as the cold front goes by–it’ll be fun for you to watch the barometer today and see the minute the front goes by as higher pressure begins to squash down on you.
Rain might reach briefly moderate intensity (defined by official weatherfolk as 0.10 to 0.30 inches per hour). It would be great if it lasted an hour at that rate, but it likely won’t. Its moving pretty fast, and it doesn’t seem like more than 2 h of rain can occur today. Look for a nice clearing in the afternoon, and a COOL evening.
Drive south if you want to avoid rain today. Jet core (in the middle levels, 500 millibars, 18, 000 feet above sea level) is almost overhead, and just to south, and that core is almost a black-white discriminator of rain here in the cool season. So, we’re on the edge of the precip today. More to the north; less to the south.
Some clouds for you
1O:55 AM, December 11. Thought you should see this nice line of Ac castellanus and floccus underneath Cirrus spissatus.7:02 AM. Sunrise.12:32 PM. Wind picking up at the ground and aloft. Note tiny Ac lenticular with Cu fractus clouds.3:14 PM. The high cloud shield from the storm encroaches. Could call this either Cirrus spissatus or Altostratus translucidus.5:22 PM. Now we’re talkin’ Altostratus with underlit mammatus and fine virga. So pretty.5:29 PM. A late “bloom”, not really expected. Shows that there was a clear slot far beyond the horizon. Had to pull off by the Refuse Waste station on Oracle to get this. I hope you’re happy.
The weather ahead and WAY ahead
Speaking of bowls, and let’s face it, with only a 100 or so we could use a few more1; we here in all of Arizona are in the “Trough Bowl” now.
This means that troughs (storms and cold fronts) that barge into the West Coast will gravitate to Arizona instead of bypassing us and they will do that over and over again. Being in the Trough Bowl is great fun! Lots of weather excitement for weather-centric folk like yours truly. When you’re in the Trough Bowl, the weather is “unsettled”; is NEVER really nice (if you like sun and warmth) for very long because a new front/trough is barreling in at you.
So, while today might be a little disappointing, we will have many chances to get the “real thing”, i.e., a behemoth of a trough among the many that affect us in the weeks ahead.
In the longer view, a behemoth of a trough for the Great SW has just popped out of the models1 just last night in the 11 PM AST run! Gander this monster truck trough for AZ. Where’s that monster truck event announcer, we need him now!
Valid for 11 PM AST, Christmas Day! Wow. Can’t really take this at face value that far out, but if it did happen, likely would be snow in the Catalina area, and horsey would likely need a blanket after it went by. Will keep you informed periodically about this as the days go by.
OK, enough weather “calories” for you today. Hope you’re excited like me.
The End
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1Furthermore, why don’t we have bowls for women’s teams, what happened to Title IX there, maybe Beach or Sand Football? )
2As rendered by IPS MeteoStar, which is about to go from “free” to “fee” in January. Dang.
Great news! Another decent rain assured now sa the models have converged on rain here on the 12th during a nice, and very sharp cold front passage, those in which the temperature can fall from a toasty 60s to 43 F over an hour along with a withshift to the NW from gusty SW winds. So we have quite a dramatic weather event coming up. Here’s what the Canadians have to say about it:
Valid at 5 PM AST, Saturday, December 13th. Areas where the model has calculated precipitation during the prior 12 h, are marked, from light to heavier amounts, green to blue to yellow. There’s a little yellow area of heavy precip over Catalina (see arrow, lower right), and that’s why I am posting this panel!
But what does it all mean, all the models predicting rain for Catalina on the 13th? Here’s what it means:
The chance of measurable rain here on Saturday, the 13th is now more than 100 %; its in the bag. Count on it. This is weather forecasting at its best. The rain may start in the early morning hours of the 13th.
The models have varied drastically on the amounts of rain, and so there’s quite a range that could occur. From this keyboard:
Minimum amount is 0.15 inches (10% chance of less than that)
Maximum amount, 0.80 inches (10% chance of more than that)1
Since the average of those two theoretical “extremes” dreamed up for this situation by yours truly is 0.425 inches, that’s my personal prediction for my house. It helps, too, that I am the same person who will also measure the rain as well.
Will look, too, for a little ice in the rain toward the end of it as the temperature plummets after the cold front goes by.
So, what’s yours? (Everyone should have a personal prediction.)
Yesterday’s clouds
Not much going on, mostly Cirrus, then Altostratus in the afternoon, that gray icy sheet that dimmed the sun so well. However, there were a few flakes of Cirrocumulus.
7:41 AM. Kind of a mess. Some ancient contrail streaks (streak in center), natural Cirrus, and some Cirrocumulus flakes (dark thin lines). Because the sun is low, Cc clouds can have shading, otherwise, no.4:19 PM. Classic Altostratus clouds, deep icy ones with tops at CIrrus levels, typically 25-35 kft or so above sea level. Published meteorogists, looking at satellite imagery, often call this cloud “Cirrus.” How funny is that? They do that because they see in the satellite imagery that the tops are cold, less than -40 C and don’t realize that only a patchy type of Cirrus, spissatus, can have shading! How funny is that, again? But, here, my reader knows better than that!
Enough fun for today….
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1Reluctantly, I remind the reader that the maximum rain amount seen for the last storm, 0.40 inches (10% chance of a greater amount), was laughable; 1.16 inches fell in Catalina/Sutherland Heights. However, in formulating an excuse, CM would point out that the models didn’t see it coming either.
While waiting for the next storm and watching harmless CIrrus and Altostratus clouds float by today, I thought it would be good for you to review our weather symbols, weather “hieroglyphs,” if you will. If you are a user of them already, you know that they can make your weather/cloud diary more official looking, add luster to it.
If you have not seen these official symbols before, which are displayed below, it would be good for you to memorize and practice copying them down. Since redundancy and repetition are the greatest tools in memorization, the symbols below are repeated several times; also so that you don’t skip over one.
As a practical hint, these weather symbols also make great design elements in wrought iron gates, doors, and fences for the truly weather-centric person!
A snap quiz next week will feature questions like, “Draw the symbol for a severe sandstorm”, or the one for sleet (frozen rain drops that bounce off the pavement, aka, “ice pellets”), and of course, a real favorite phenomenon here, one often discussed, “Draw the symbol for drizzle.” Remember, a symbol is worth a lot of words!
Still looking at a number of storms ahead, December 12-20th. Here’s one, hot off the 00Z WRF-GFS model run based on global data from last evening, as rendered by IPS MeteoStar:
Valid at 5 PM AST, December 20th. Colored regions denote areas where the model thinks it has rained or snowed during the PRIOR 12 h. An arrow points to SE Arizona.
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!
—————————–
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!
