1While several inches of model2 rain has occurred in Catalina and in the nearby mountains this month, most of which cloud-maven person has festooned his blog with model panels of, there really hasn’t been any ACTUAL rain.
But having said that, there is even MORE model rain ahead, some beginning tomorrow in these parts. Tomorrow’s rain comes from a sub-tropical minor wave ejecting from the sub-tropics. You know, as a CMJ, a wave from that zone means a ton of high and middle clouds, i.e., likely DENSE Altostratus with virga, something that was seen yesterday off to the SW of us. This time, though, some rain should fall from these thick clouds, though almost certainly will be in the trace to a tenth of an inch range between tomorrow and Monday morning.
Model rain from 11 PM AST global data then falls in Catalina on:
February 24th
March 1st
March 7-9th
with the model total rain in these periods likely surpassing an inch or more! What a model rain winter season this has been! Astounding. The model washes have been running full since late December, too!
BTW, that last model rain period is really a great one, a major rain for ALL of Arizona!
Some recent clouds I have known and a couple of wildflowers
7:36 AM, Thursday, Feb 19: Iridescence in Cirrocumulus.7:52 AM, Thursday, Feb. 19: Iridescence in Cirrocumulus with a tad of Kelvin-Helholtz waves (center, right), ones that look like breaking ocean waves. Kind of cool looking.9:29 AM, Thursday, Feb. 19: Altocumulus perlucidus exhibiting crossing patterns, rows perpendicular to each other. Makes you think about football and people running out for passes.9:42 AM, Thursday Feb 19: An extremely delicate crossing pattern in Cirrocumulus, center. You’ll have to drill in good to see it, but its worth it.10:39 AM, Thrusday, Feb 19: Pretty (mostly) Cirrus spissatus, a thick version in which shading can be observed.6:13 PM, Thursday, Feb 19: No idea what that stick contrail is. Looks like a flight pattern to induce weightlessness. Climb rapidly, round off the top, and then go down. You can be weightless for maybe 10-30 seconds. Been there, done that in a C-130 Hercules, last FACE flight of 1973, Bill Woodley lead cloud seeding scientist. But, you pay a price, get smashed on the floor as the aircraft comes out of the dive. You cannot get up!Let’s zoom in and see if we can learn more about what happened here. I think a jet pilot was having fun. Nope.6:54 AM, yesterday. Altostratus virga provides a spectacular, if brief sunrise over the Catalinas.6:15 PM last evening.From a dog walk this VERY morning, a desert primrose.And a desert onion bloom.
The End. Hope you enjoy the copious model rains ahead!
a lot….beginning tomorrow afternoon or evening, not today. Today is “pause” day. Also, its trash day today here in Catalina, mentioned here as a public service.
Slow moving, sub-tropical system to drop several inches of water content in rain/snow in mountains, sez our best model, that run by the U of AZ. Thank you, U of AZ, btw. Below a snapshot of the total precip from that 5 PM AST global data crunch, “nested” for AZ. This plodding gigantostorm should keep the water coming down the washes, luxuriate our sprouting wildflowers, some of which, like desert asters, are beginning to emerge and even bloom1:
Total precipitation ending just after midnight, Feb 2nd, as seen by the WRF-GFS model run from 5 PM AST last evening. Catalina/Oro Valley appears to be in a bit of a shadow, so while Ms. Lemmon and vicinity are forecast to get several inches of water content in rain and snow, Catalina gets an inch–though hard to see in this graphic. Why? Likely south to southeast flow coming downslope off the Catalinas. But, I think its WRONG!
Lot’s of gray sky photograph opportunities ahead. Get camera ready. Not much in the way of rain seen in mods after this, so enjoy this rain “chapter” of your life as fully as you can.
Yesterday’s clouds
After another light shower boosted our storm total another 0.02 inches, a fabulous, wonderful, almost Hawaiian like day followed with a little humidity in the air, deep blue skies, and white puffy clouds, ones a true cloud maven would call, Cumulus clouds and would be ashamed if he just said they were “puffy clouds.”
7:34 AM. Sun tried to break through some puffy clouds over the Catalinas after our 0.05 inch shower. A few, very small shower cells were around, but didn’t look like much at this time.7:53 AM. Gee, a strong, though narrow rainshaft developed SSW of Catalina, upwind! Suggests a Cumulonimbus-like protruding, icy-looking top up there on top of the shaft.
8:08 AM. The three amigos rainshafts, headed this way, evnetually dropped another “surprise” 0.02 inches. Earlier model runs had indicated the rain would be over by dawn yesterday.
8:34 AM. One of the “amigos” hit Ms. Lemmon and Sam Ridge nicely. Ms Lemmon racked up 0.59 inches out of the storm overall. Very nice, considering our 0.07 inches total.8:53 AM. As we know so well, sometimes the best, most dramatic shots are those after the rain passes, and the rocky surfaces glisten in a peak of sunlight, here enhanced by crepuscular rays due to the falling rain. A rainbow was also seen, but not by me somehow.
8:54 AM. Closer look at glistening rocks toward the Charouleau Gap.
11:45 AM. The deep blue sky, the puffy clouds topping Sam Ridge, the strong sun, the bit of humidity, the bird flying along on the left, gave the sense of one being in Hawaii I thought.12:32 PM. Puffy clouds still top Samaniego (Sam) Ridge.
2:28 PM. Small puffy clouds provide a “postcard” view of Catalina, Saddlebrooke and environs. Visibility here well over 100 miles. Never get tired of these views! You got some Cirrocumulus up there, too.
2:51 PM. Another postcard view of our beloved Catalina. Rail-X Ranch and the Tortolitas off in the distance, left. Nice patterned Cirrocumulus up top above the little puffy clouds.
5:58 PM. The day ended with a nice sky-filling sunset as a Cirrus layer was lighted from below by the fading sun. The lines of virga show that while Cirrus clouds don’t have a lot of water vapor to work with up there at -40 C (also -40 F), the crystals that form are still large enough to settle out as precip.
The End
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1Desert Aster (I think) in bloom seen on the link trail from the Baby Jesus Trail to the Deer Camp Trail.
Seen on big hike, Jan. 22nd. This plant will be so happy by next week!
The most wetness I could find for Catalina residents is in this here model run from last evening, 11 PM AST. Rains on the 27th into the 28th, as was mentioned as a possibility here some days previously, then it rains from the 29th into February 1st (new!) Prior model runs before this one last last night are much drier; are not shown, nor will they be discussed.
Gut feeling, which is what we meteorologists went on before the era of computer models, and frankly, its a feeling coming from a forecaster who suffers from “desert precipophilia1“, makes me think this wetter model run will be more correct than the bad, drier model runs that preceded it.
However, the rain in the first episode, 27th-28th, this from that system deep in the tropics, looks awful light, probably from mid-level clouds. Just looks like its not going to have much left when it gets here. An awful of rain, however, will have fallen on the ocean west and southwest of Baja California, though, before it arrives.
The later storm at the end of the month looks stronger. See the panel below, which I have pinched off IPS MeteoStar and have placed here since I suspect you won’t really look at it and I have to do pretty much everything for you:
Valid at 11 PM, January 30th. The colored regions denote those area where the model has calculated that precipitation has fallen during the PRIOR 12 h. Blue denotes heavier precip. A bunch of arrows have been added to show approximately where we are in Catalina, AZ. This is from our WRF-GFS model output based on last evening’s 11 PM global data, as rendered by IPS MeteoStar, a company who will be soon charging for these images it appears, they are that good. Nice rains in TX and OK, too.
Is spaghetti supportive of a wet Catalina in the near future, this latest off-the-computer-presses-to-you model run?
Not so much.
But then spaghetti let me down when I told a friend that “it was in the bag” for rain in Monterrey, CA on the 17 or 18th of Jan, about 12 days ahead of time, based on spaghetti. Didn’t rain at all. “Hey, take a bite out of credibility.”
So, we’ve been chastened royally here, as a British citizen might say; the deliberate errors in the “ensemble” plots sometimes aren’t big enough apparently compared to the goof ball measurements that sometimes come in. So, I’ve downplayed the idea that spaghetti is all knowing. It could be WRONG/misleading at times, anyway.
However, to balance the spaghetti picture, the encroaching trough coming in over us tomorrow WAS well predicted, long in advance. Unfortunately, it looks a little too dry to produce measurable rain, just a drop in temperatures. But, there should be some nice cloud scenes.
Some recent clouds
5:52 PM, Jan 18th. Nice patchy Cirrus clouds with a couple of flakes of droplet Altocumulus clouds floating around below them.2:25 PM. Patchy Cirrus fibratus or “intortus”–the latter meaning kind of a tangled mess in appearance.4:43 PM. Cirrocumulus undulatus, those just-formed clouds on the right, and at the upwind side of this complex (air movement from right to left up there). Those clouds on the right likely start out as very small droplets, but then freeze almost instantaneously, followed by fine trails of ice crystals that begin to settle out. You can see this fallout happening in the older thin Cirrus clouds at the upper right. Gravity waves like this, resembling ocean swells, ones that produce the “undulatus” variety of clouds, are common in atmosphere. When the air is very near saturation, we get to see them.4:56 PM. Kind of the same thing happening here, though a old contrail has messed things up a bit (angles toward the right lower corner). Middle right, you can see the very fine trails of ice crystals heading down.
The End
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1Does not appear to have a biogenic culprit. The origin of this affliction is currently unknown.
It doesn’t get much better than this plot below for our Catalina weather 10-13 days ahead, which is always pretty fuzzy-looking as a rule. “Better” means for rain chances here, which is not everyone’s “better.”
Here’s the excitement:
Note blank area, that is, an area free of lines area centered on the gambling and other mischief-permitting State of Nevada1.
Note how the red lines dip down into Mexico, whilst the blue lines bulge northward into Canada along the West Coast.
This error-filled plot2 tells us that it is almost certain that a trough will be in the lower middle latitudes where we are on January 22nd or so. Just about guaranteed.
In the meantime, those blue lines indicated that a ridge of high pressure is going to divert northern storms into Canada and southeast Alaska. Sometimes we refer to situations like this as “split flow”; the southern portions of storms in the Pacific move ESE toward southern California and the Southwest, while the northern portions split off to the NE, as is happening now. Weak upper level disturbances pass overhead, the next one tomorrow, and with it, a little more rain, the models say.
U of AZ mod has rain moving in toward dawn tomorrow with totals here amounting to about like that last rain, 0.10 to 0. 25 inches. Given model vagaries, probably the lower and upper limits here are likely to be 0.05 (worst case scenario) and 0.50 inches (best case scenario), so a best guess would be the middle of those, 0.275 inches, not too much different from the AZ mod. This is the sports-like part of weather forecasting. What’s your estimate, fantasy or otherwise?
BTW, there were quite a few stations reporting over an inch of rain in Santa Barbara and Ventura Counties during the past 24 h, and so while weak, this system is pretty juicy, lots of liquid water as measured by dewpoints which should rise into the upper 40s to low 50s here during the next day. Also, there have been some embedded weak Cumulonimbus clouds and that’s a possibility here tomorrow, too, as the rainband goes by. You’ll be able to tell that by strong shafting below the clouds. As always, hoping we here in Catalina get shafted tomorrow.
But the ones these days are weak, while the split ahead in 10-13 days is likely to contain much stronger disturbances, well, at least ONE before it gives out.
Yesterday’s clouds
7:22 AM. Sunrise Altocumulus.
11:42 AM. Another very summer-like looking day with clouds beginning to pile ever higher over the Catalinas.
12:51 PM. Small Cumulus are developing over the Catalinas while far above them are, two crossing contrails, about the same age suggesting that aircraft crossed paths simultaneously. The FAA flight separation rules now allows for 1,000 feet of separation instead of the 2,000 feet in years past, and so if you’ve flown recently, you may have noticed planes that appeared to be a lot closer to you than ones a few years ago. This has been permitted due to improvements in aircraft GPS accuracy, and was deemed needed due to the vast increases in air traffic in the decades ahead. Still, there were times when opposite flying aircraft were so CLOSE, passing by like bullets, that you wanted to scream to the pilot, “Hey, wake up and smell the air space!!!!”
1:44 PM. Probably had a little ice in that smooth section, but overall really looked like a miniature summer Cumulonimbus cloud. Did not see if it had an echo, and never was it clear that there was ice.2:02 PM. As Altocumulus castellanus overspread the sky, lenticular clouds were still visible beyond the Catalinas. Some lenticulars began to sprout turrets, an odditity, but one driven by the condensation of water, something that releases a little heat (in this case) to the atmosphere causing the cloud to be more buoyant.
5:32 PM. A sunset of Cirrus and Altocumulus. Not bad.
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1What a great and honest state motto that would be! “Nevada: That US State where gambling and other social mischief is OK with us!”
2Don’t forget that due to growth in computer capabilities, we can now have many model runs from the same data and be done with them in a timely way. These “spaghetti”, “ensemble” or better yet, “Lorenz” plots are computer model runs with deliberate (!) slight errors introduced to see how the model forecasts of high and low pressure centers changes, given a few slight errors. This is because there are ALWAYS errors in the data anyway, there are always error bars on measurements, etc. By doing this, only the strongest signals in the forecasts remain, indicated by grouping of lines these two colors of lines, red and bluish. So, the forecast of the jet stream coming out of Asia is very, very reliable. Things go to HELL, downstream (toward the east), but some likely patterns can still be seen, such as the one over the Southwest US where a trough/low is almost certain in our area then. Will it bring us rain in Catalina? Hell, I don’t know because if the trough is a little too far to the east of us, we might only get cooler. However, since Cloud Maven person has a postive rain bias, he will say, “Absolutely. There will be rain in the Catalina area on January 22nd or so”–the actual timing might be off by a day or so.
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:
The End
—————————————————– 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.
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.
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.
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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.
Here we go…..some pretty, but also dull, photos, along with some novella-sized captions as mind wandered into the obtuse while writing them.
6:44 AM. Nice sunrise due to Altostratus/Cirrus ice clouds.2:00 PM. Kind of a dull day yesterday, kind of like this blog. Stratocumulus (Sc) clouds topped Samaniego Ridge most of the day, below that gray Altostratus ice cloud layer. But those Sc clouds were too warm to have ice in them, and droplets were too small to collide, stick together, and form misty drizzle. Have to get to at least 30 microns in diameter before they stick to one another. Misty drizzle? Could be a great name for a late night female vocalist doing earthy songs like Earthy Kitt back in the ’50s. “Earthy” was much hotter than global warming.3:29 PM. An Altostratus translucidus to opacus, mostly ice-cloud with a dark patch of Altocumulus droplet cloud blocking the sun. If you look closely, (upper center) you can see a that there’s this Altotratus layer may be topped by a Altocumulus perlucidus droplet cloud layer. Yes, droplet clouds at the top of As where the temperature is lowest? Yep, this counter-intuitive finding happens all the time, up to about -30 C -35 C. Been there, measured that; in aircraft research. Ma Nature likes to form a drop and have it freeze before forming an ice crystal directly from the water vapor.4:40 PM, shot taken as we entered a local restaurant. You’ve got your two layers of Altocumulus, with some Altostratus translucidus above those, filling in the gaps. Gaps? Huh. I am reminded that I have a failed manuscript about “gaps”, these kind; Cloud Seeding and the Journal Barriers to Faulty Claims: Closing the Gaps., rejected by the Bull. Amer. Meteor. Soc. way back in ’99. It was an instruction manual, in a sense, about how to prevent all the bogus cloud seeding literature that got published in the 1960s through 1980s, and was not only published, but cited by our highest national panels and experts, like the National Academy of Sciences. Amazing, but true. I give examples. You can read about this chapter of science in Cotton and Pielke, 2007, “Human Impacts on Weather and Climate”, Cambridge U. Press, a highly recommended book. That cloud seeding distortion of cloud seeding science was due to many factors, of which perhaps the primary one was, “nobody ever got a job saying cloud seeding doesn’t work1.” This was a great segue. Of course, we have similar stresses on those researchers looking for effects of global warming nee “climate change” now days. Nobody will ever get a job (a renewed grant) saying they can’t find evidence of global warming, “Can I have some more of that money to keep looking?” And beware the “Ides of March” if you criticize published work in that domain! Think of poor Judy C , a heroine to me, and how she’s been vilified for questioning climate things.
5:29 PM, took leave from Indian food there in R Vistoso for this. Its not just anyone who would excuse himself from dinner to do something other than visit the laboratory.
That’s about it. No use talking about the rain ahead again. Seems to be a couple chances between the 20th and the 30th.
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1You can make a cloud snow a little by seeding it with dry ice or silver iodide. This has been shown since the earliest days of experiments. Below, to demonstrate this, an aircraft inadvertently “seeded” this Altocumulus cloud layer. However, whether the small amount that falls out from previously non-precipitating clouds is economically viable is not known. Increasing precipitation due to seeding when the clouds are already snowing/raining has not been satisfactorily proven. As prize-winning stat man, Jerzy Neyman, U of Cal Berkeley Golden Bears Stat Lab would tell you, you need a randomized experiment and followed by a second one that confirms the original results, with measurements made by those who have no idea what days are seeded and evaluations done by those who have no vested interest in cloud seeding. Wow there’s a lot of boring information here. Getting a little worked up here, too.
Ice canal in supercooled Altocumulus clouds over Seattle, bases -23 C, tops -25 C (from PIREPS). Photo by the Arthur.
Finally found some rain for you. Took awhile. Came from the 11 PM AST global data from last night using the WRF-GFS model, our best. The rain falls around the 19th, “only” 11 days from now and during the “sweet spot” for southern California rain in mid-November, 10-20th, which gives it a few more percent of credibility than it otherwise would have.
BTW, there is virtually no support for this pattern from the NOAA spaghetti factory. So, all of the discussion below about an upcoming rain in Catalina might erroneous, based on a personal hunch about an outlier model run being the correct “solution”, one based on experience, and to HELL with spaghetti1, a study in forecasting subjectivity, etc.
Got that Bay Area rain timing info originally from C. Donald Ahrens, the big author of Meteorology Today and Essentials of Meteorology, both of which have about 400 editions out by now, while he and I were at San Jose State College University.
Don, a grad student then, and me, and undergrad, worked and sang together to Top 40 songs radiating from KGO-FM 2,3 in a little corrugated metal building there by the San Jose State football stadium back in the late 60s, and it was somewhere between songs that he told me about his findings.
Don had done a rain frequency study for the Bay Area for a local insurance company and it turned out that he found that it was somewhat more likely to rain in the middle of November than earlier or later in the month. That rain fell more more often than earlier was no surprise, but more often than later in the month was. Later I found that it was also true for southern California.
Sometimes oddities like these are referred to by big professors of weather, like Reid Bryson at the U of Wisconsin Badgers, as “singularities”, a weather pattern that tends to recur year after year around the same time of the year, like the so-called “January thaw” in the East which I don’t think happened last year.
So, ever since Don told me about the mid-November peak of rain in the central and southern parts of Cal, I have looked for it year after year and it seems to turn out quite often, and this November seems to be no exception, though the models were resisting this pattern for quite awhile before “giving in.”
Well, anyway where was I? It seems that the southern California rain is now being foretold for around 18th of November, and a day or so later it trudges on into Arizona. From IPS MeteoStar, a Sutron Company, whatever that is, this wonderful map:
Valid the night of November 19th-20th. Colored regions denote those areas where the model thinks it has precipitated during the PRIOR 12 h. So, storm has arrived here during the day on the 19th.
Some clouds
we have known over the past few weeks while CM was re-hydrating mentally:
Some ice for you on a warm fall day.Some ice for you on a warm fall day (virga from Altocumulus castellanus and or floccus)Pretty iridescence (or irisation) in a Cirrocumulus cloud.Pretty sunset, Altocumulus featured.
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11The non-supportive spaghetti plot from the 00 Z (5 PM model run from last evening):
Valid at 5 PM AST Wednesday, November 19th. Arizona is in a low amplitude ridge, according to most of the “members” of the repeat model runs with itty-bitty errors deliberately put into them. I have rejected this plot and look for validation of this action around the 19th of November. You will not hear about it further if I am erroneous in this action!
2An odd, almost mysterious Frisco FM radio station with no commercials featuring, “Brother John.” We’d sing along to the Four Seasons, The Five Americans’, “Western Union” (about telegraph, the way people used to communicate before the Internet).
3 We both had quite a talent for falsetto it seemed at the time.
