Range of amounts in Catalina, given kind of a marginal moisture situation:
Goose egg to 0.33 inches max, median 0.165 inches, CMP’s best forecast. A friend and met man/prof predicts 0.50 inches here, FYI.
Looking backward
Have felt a little guilty not posting cloud photos from the last storm, Oct 30th, leading my reader into some sadness, maybe even despair the following day when she didn’t see her cloud day reprised. Here are a couple of the characteristic scenes from that day, which includes a shot of a rare drizzling cloud. You will love that shot! Also reprised here is the pioneering technique of novella-sized captions.
8:07 AM. Note how the deteriorating Equestrian Road draws your eye to the bank of Stratocumulus. Quite artistic I think. Think of Bob Dylan’s mournful line, “If today was not an endless highway…1.” Equestrian Trail Road actually ends in Sutherland Heights., just so you don’t lose focus here.8:59 AM. The easy to read sign of a wind shift, one that pushed up the tops of the innocuous Stratocumulus to a thickness where drizzle drops began to form.
9:12 AM: “Drizzle, der it is”, as might be phrased in old TEEVEE show, In Living Color. Shape of lower cloud tells you that the wind is blowing from right to left.10:33 AM. Let’s quote Bob Dylan again, this time in one of his most famous incomprehensible songs, Subterranean Homesick Blues: “You don’t need a weatherman to know which way the wind blows; a horse will do.” Well, CMP added those last few words. Bob couldn’t think of something as good as that. The clouds and horse tell you the wind is blowing from right to left. Btw, ome people were so amazed by the words in that Dylan song quoted above that they began to call themselves, “Weathermen.” How crazy was that? Who in the WORLD would want to call himself a “weatherman” that wasn’t one?
1043 AM. The perfect Cumulus congestus? I think so.4:11 PM. Rainbow. Indicates raindrops are falling over there.
4:37 PM. Just pretty, no words needed.
Still windy outside, 6:03 AM to be exact. Looks like the observation of windy is going to be correct. Expecting some nice lenticular clouds to show up today. Have cameras ready. No rain before 7:15 PM. Overnight, watch out!
Been dreaming about a white Lemmon for quite awhile, ever since the New Year’s Eve snowstorm here. Finally got one yesterday, as we saw. Here are a few extra Lemmons for you:
3:11 PM.3:42 PM.Finsihing off here with an orange Lemmon, if that’s possible, at 6:50 PM.
Yesterday’s clouds
(includes photo of a small, cute dog)
7:58 AM. Not one, but two layers of Stratocumulus.7:58 AM.7:59 AM. Interesting how the scattering of diffuse light through the clouds lights up our cherished cholla cacti.8:57 AM. Paper flowers still going…. They’re not used for making paper, btw.9:30 AM. Occasional sprinkles fell from these clouds. Likely was due to ice, but texture if the precip also suggests drizzle formation (or warm rain processes, wherein larger cloud droplets collide to form drops big enough to fall out.) I hope your cloud diary also reflected this ambiguity.3:42 PM. Later in the afternoon, small Cumulus provide the light and shadow show on the Catalinas, one of the best things about living here. No ice evident.
Looking closer, I hope you recorded the slight fall streaks (fallstreifen, ger.) in the scene above. It would have been quite an important observation for you to have acquired since these small clouds had not shown ice prior to this time. See below for the VERY delicate trails emanating from this Cumulus mediocris cloud; look between and above the orangish rock faces on the top of Sam Peak and a bit to the left:
6:48 PM. Fine snow trails fall between and above the two orange colored rock faces on the left side.The baloooooon sounding launched from the U of AZ at 3:30 PM yesterday. Where the lines pinch together was likely around cloud top, or about -10 C, close to the natural ice forming temperature we usually see here in AZ. More ice fell from layer clouds to the north at sunset, that were colder still.
The weather ahead, way out there
Next rain chance in about a week. Looks like May will start out hot, but “too hot not to cool down”, to quote Louis Prima and Keely Smith doing the Porter songbook, and pretty much that cool down before the month is hardly underway. I am sure lingering snowbirds, not wanting to have their feathers singed, will be glad to receive this news.
How can we say that with any acuity?
Check the spaghetti! Looky below at how troughy the flow is by about the 8th of May (red lines dipping toward the Equator along the West Coast). No extreme heat then, just normal warmth or below average “warmth.” This is a circulation pattern that persists, too. And with “troughy”, there’s always the chance of a rogue rain.
Valid on May 8th, 5 PM AST. No heat here. Some snowbirds have clearly left too early IMO.
Gasp these late April totals from the Pima County ALERT gauges, as of whenever you look, along side our Sutherland Heights total, as of 7 AM now, of 0.58 inches. This total is about the normal for the month of April here. Fantastic. Several nearby mountain and Catalina foothill totals are well over an inch with Oracle Ridge having 1.50 inches! However, the top of Ms. Mt. Lemmon is reporting nothing, which means the precip there is falling as snow. Nice couple of thunderblasts last night between 1:30 and 2 AM, too.
Yesterday, the latest wrf-goofus model (executed by the U of AZ at 11 PM AST night before last), had no rain in Catalina, and only a pittance in the mountains east of us.
Still a chance for measurable rain during the day today, too, but it’ll be gone by tomorrow, and it’ll likely bt a long time before rain returns.
Yesterday’s clouds
2:53 PM.2:54 PM. Cloud street again.5:39 PM. Disappeared for awhile, then came back.5:52 PM. The look of a storm, Altostratus above Cumulus and Stratocumulus.
The End, for now, anyway.
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1Total is from a CoCoRahs gauge, not the Davis Vantage Pro online tipping bucket, which registers slightly low.
Precipitation Report for the following time periods ending at: 05:19:00 03/19/15 (data updated every 15 minutes)
Data is preliminary and unedited.
—- indicates missing data
Gauge 24 h total Name Location ID#
Catalina Area 1010 0.20 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.20 Oracle Ranger Stati approximately 0.5 mi SW of Oracle 1040 0.24 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.31 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.20 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 ——1 Cargodera Canyon NE corner of Catalina State Park 1080 0.24 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke 1100 0.16 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains 1030 0.39 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak 1090 0.43 Mt. Lemmon Mount Lemmon 1110 0.24 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp 1130 0.51 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.47 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.59 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station 2280 0.63 Green Mountain Green Mountain 2290 0.39 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
More rain is possible, but likely less than yesterday. For the best possible forecast at this hour, check out the U of AZ model.
And why izzat, more precip in mountains?
Let us turn to the cartoons of Rangno 101, summer of 1987, below, where Rangno was forced into teaching a 101 summer class that year in the Dept of Atmos Sci2, University of Washington, when the Ph. D. student that was supposed to do it opted out a the last second, maybe transferred to another team. U of WA accreditation suffered that summer because Rangno did not have the Ph. D., nor even the Masters Degree and yet he was teaching a class. How wrong is that? It can’t be worse than that.
Illustrative diagram of why more in mountains: collection, lack of evaporation. Its kind of what we had yesterday for most of the day. Lower Stratocumulus clouds accumulating on the upwind side of the Catalina Mountains, including Samaniego Ridge, while rain/snow falls from a higher deck. Sometimes this has been called the “seeder-feeder” situation, where the lower cloud is the “feeder.” “Bellevue” should be Catalina, and the “Cascades”, the Catalina Mountains. The main point is that the “feeder” cloud may not precip on its on, but stuff that falls into it gets bigger, increases precip rate.
To emphasize what happens to a drop falling through a collectible cloud, I now show this analog:
An image of precipitation particles arranged by size. Represents what happens when a smaller drop falls into a cloud with droplets above about 20 microns in diameter. They can’t get out of the way fast enough and so are collected by that falling particle. Could be a snowflake or single ice crystal, too, that fell into the droplet cloud.3:30 PM. Lower Stratocumulus builds over Pusch Ridge on a dank afternoon.3:31 PM. Looking at Samaniego Ridge, You can see how the lower clouds are enhanced as the air piles up (gently yesterday) against the mountains.
The incredible weather predicted way out there on the horizon
“Jumbotron” AZ storm showed up again yesterday, in a the second model output. These forecast maps are AMAZING in showing what must be equal to the heaviest rains ever observed in an April in southern AZ. Check this series out (from IPS MeteoStar). I can’t can’t describe how much I love these maps, and I felt, even though the model run is now almost 24 h old (from yesterday’s 12 Z run), that you should see them, too. More importantly, I will ALWAYS have them to look at since they will be overwritten by the next 12 Z run, but they will still be in my blog files. The NOAA “spaghetti” plots has a little support for a trough coming out of the lower latitudes, so we can likely expect something at the beginning of April.
Valid March 31st, 5 PM AST. Possible big rain moves in from the low latitudes.Valid Wednesday, April 1st, 5 AM AST. LOOK at the rain that moves into AZ!Valid Wednesday, at 5 PM AST. Unbelievable for April. Hope it doesn’t turn out that way.Valid at 5 AM AST, April 2nd. The pounding goes on.Valid at 5 PM AST, April 2nd. Two day rains of unprecedented model proportions come to a close.
The End
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1Looked OK when we rode by it a coupla days ago…
2:55 PM, March 15th. The Cargodera Canyon gauge is shown underneath the gigantic writing.
2Widely regarded as the best atmos sci department in the world until that time; you walked the halls with giants in those days.
Kind of a dull day yesterday. Not much to look at. Some Altocumulus with an interesting, slotted wave pattern to start was about the only interesting thing in the morning.
Then some small Cumulus that continued to agglomerate into masses of dark Stratocumulus, with a little rain to the north of us. You probably didn’t see it. The darkness of the clouds was likely due to higher than normal droplet concentrations, which in clouds, causes the bottoms to be darker because the smaller droplets associated with high droplet concentrations causes more sunlight to be reflected off the top of clouds. But you knew that.
You probably also know that the brief, and weak shafts of rain to the north of us in the afternoon meant that cloud tops were barely reaching the ice-forming level, certainly were mounding ones, analogous to the rolling hills of Ireland rather than ones protruding upward very much like Kilimanjaro or something like that.
Sunset was OK, not great.
A stupendous storm showed up in the fantasy part of the model run, out two weeks, or on April 1st. That’s a little late for a stupendous storm, but it was fun seeing the computer maps of one.
Today, and not just because I am lazy and have to go right now to feed some horses, I thought I would just insert all these images in whatever way WordPress decided they should go and let you puzzle them out, e.g., name clouds, figure out what time was the photo taken, or, just look at them as a review of your cloud day.
Btw, whilst out on dog walk yesterday, saw that in the Cottonwoods area by the Baby Jesus Trailhead, several 6-9 inch diameter cottonwood tree branches were blown down during Sunday’s windstorm, one younger tree had been topped. Looked like a very small, supergust burst had done it, maybe less than 50 yards in diameter.
I figure today’s weather is pretty well presented by the NWS, and your favorite weathercaster, so why duplicate good efforts?
10:47 AM. Altocumulus perlucidus undulatus translucidus (has waves in it; is thin).
The End, of one of the easiest blogs yet! Maybe will practice more WordPress chaos in the future!
Drops, that is. There were about 140 or so the night before last, noticeable only if you left your dusty car outside, and TWO drops yesterday between 4:08:22 and 4:08:51 PM, as the last remnant of a shower cloud moved overhead from The Gap (the Charouleau one).
You HAD to be outside running around to encounter them, I do mean “running”, to increase the sample volume and your chances of detecting a drop in marginal rain situations. You have to “want it”, to be the best you can be about traces, that is. And I wanted to report another trace real bad. I love to report traces of rain, the most underrepresented rain event of all, the poor relative of measurable rain.
And, of course, more shower chances ahead, March 17th through the 20th, as remnant of the upper level trough that produced our last two days of clouds and sprinkles returns to us like a boomerang after producing generous rains in Mexico. It also meshes with a weak trough from the Pac at this time, so its pretty troughy for a few of days. Nice.
Today’s cloud pic archive will begin with the sunset the evening before last, since domestic responsibilities1 prohibited posting the usual tedious cloud array yesterday.
6:32 PM, March 12th. Rosy glow, a nice name for a female western singer, as well as a sunset, that bloomed late in the day (was less spectacular than expected that day, but still something). Lots of virga spewing out of iced up, high and cold-based, Stratocumulus clouds. Since you wanna know more, the TUS sounding indicated bases at -10 C, and tops at -20 C (4 F), that latter temperature explaining all the ice that formed that day.
Yesterday’s clouds
The temperature structure aloft was pretty much the same as the previous day, except that cloud bases were slightly lower and warmer, “only” -7 C or so, with tops again around -20 C (4 F), plenty cold enough for plenty of ice and virga from the modest Cumulus and Stratocumulus clouds that developed later in the morning.
Rainshafts were that tiny bit heavier it appeared, seeming to reach the ground with more gusto than the similar day before.
11:44 AM. Groups of small Cumulus began forming over the mountains.1:23 PM. Cumulus and Stratocumulus fill in the sky. Slight virga is apparent if you look really hard.2:29 PM. A light rainshower douses Marana and vicinity. Note the rumpled top of this cloud suggesting dominance of the water phase with just ice underneath. The dark bottom of the cloud is often called a “cloud base” by pilots, but is really the transition zone where the snow is melting into the more transparent rain and is not really a Cumulus cloud base, one composed of droplets forming in an updraft, as in the prior photo.
3:58 PM. Rain shaft on The Gap. Can you detect it? Its coming right at us! Here’s where the responsible observer realizes that he must be outside, or provide another means of detecting isolated drops as the cloud head begins to pass.
And, below, why we love our mountains and desert, especially on these kinds of days. About this time, the “light show” begins, ending with a dramatic sunset.
6:14 PM. Even the horrible becomes beautiful in the evening light.
The End
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1I had to take my mom, whose she’s really old and fragile, to the doctor , and then to the supermarket. This personal information posted for the purpose of inducing empathy in case I have a really bad forecast. People will remember that I take my mom places.
Above, a typical Los Angeles Times headline for a southern California storm when the writer was growing up, one framed for Catalina. Few storms don’t do this, so it was always kind of funny.
To coninue on a nostalgic stream for some reason, the LA Times also had a very weather-centric publisher-owner1 in those days, and after a storm, there was also a HUGE rain table in the paper. I loved ’em, scoured those tables to see who got what amounts, and I think a lot of people do like them, so’s that’s why I put a rain table in here from time to time.
Below, the Pima County ALERT gauges 24 h precipitation totals ending at 3:24 AM today, covering the first batch of rain. Scattered light showers, possibly today, but more likely tomorrow, may add some to these totals, but not very much.
The Sutherland Heights portion of Catalina received 0.57 inches.
Gauge ID Name, Location
Catalina Area
1010 0.67 Golder Ranch, Horseshoe Bend Rd in Saddlebrooke
1020 1.02 Oracle RS, approximately 0.5 mi SW of Oracle
1040 0.63 Dodge Tank, Edwin Rd 1.3 mi E of Lago DO Parkway
1050 0.71 Cherry Spring, approximately 1.5 mi W of Char. Gap
1060 1.10 Pig Spring, approximately 1.1 mi NE of Char. Gap
1070 MSG Cargodera Canyon, NE corner of Cat. State Park
1080 0.98 CDO @ Rancho Solano, CDO NE of Saddlebrooke
1100 0.55 CDO @ Golder Rd, CDO at the Golder RD bridge
0.81 inches average
Santa Catalina Mountains
1030 0.87 Oracle Ridge, about 1.5 mi N of Rice Peak
1090 0.51 Mt. Lemmon, snow melt will add to this
1110 1.10 CDO @ Coronado Camp, CDO 0.3 mi S of Coronado
1130 1.30 Samaniego Peak, Samaniego Ridge
1140 1.30 Dan Saddle, Dan Saddle on Oracle Ridge
2150 0.43 White Tail, Catalina Hwy 0.8 mi W of Palisade RS
2280 0.51 Green Mountain, Green Mountain
2290 0.28 Marshall Gulch, Sabino Creek 0.6 mi SSE of Gulch
Your storm day, beginning with a morning light show amid the overcast Stratocumulus:
7:26 AM. Spotlight on the Tortolitas.7:25 AM. Light on Saddlebrooke and environs.7:27 AM. Closeup of the sunny highlight on Saddlebrooke.7:49 AM, toward the C-Gap. Breaks in the overcast (BINOVC, as we would text that) reveal a higher layer of Altocumulus clouds. Nice lighting here, too.8:00 AM. Streams of dark Stratocumulus clouds rolled across the sky for hours yesterday with no rain falling from them. I bet you know why they didn’t rain.9:36 AM. The Stratocu had deepened up enough by this time to begin preciping, and I am sure you made a note of this. The misty nature of this made you also think it might be a “warm rain” process, one not involving ice crystals. However, it did not continue.11:33 AM. Light showers finally began to develop SW of Catalina after a two hour hiatus. Remember how we were thinking that showers might be numerous by now. Well, it didn’t happen. But even these pretty much fizzled out on their way here.12:31 PM. The wind shift line marking the cold front, marked by an arcus cloud (a sharp lowering of cloud bases in the lifting, cooler air), appeared NW-NE of Catalina. Real rain was just ahead.1:55 PM. Eventually the arcus cloud (horizon) and wind shift line made its way across Oro Valley. You can see how that clash of winds has deepened and darkened the clouds over it. Was thinking, “Here we go!”, deep Cumulonimbus clouds would now develop, likely as you did, too. But only weak, puny ones did likely with crappy, mounding tops.2:09 PM. Sure, there was a nice shaft, and was hopeful this would lead to some thunder, but it pooped out even before getting here! Wind shift line seemed to come in two surges, the first one dying out.6:18 PM. Sun tries to perform a colorful sunset, but fails.6:18 PM. Reflected light off orange cloud tops, or a higher layer being underlit by the fading sun, created a mysterious orange glow on the Catalinas and Pusch Ridge.4:50 PM. Some potential for flooding was forecast, and here we see that it indeed verified yesterday.
The weather way ahead
A pretty good rain threat still appears in the March 11-15th window.
The End, except for a gigantic historical footnote below.
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1In 1981, at the prodding of Otis Chandler, the weather-centric owner of the Times, there was EXPANSION of the weather page while the paper devoted an astounding amount of pages to a review weather reporting in the media entitled, “Weather: Everyone’s Number One Story.” One side bar, embedded in this HUGE article took note of the Los Angeles weather situation with the humorous side bar, “Little rain, but lots of coverage.” You can see that article below, scanned from the original clipping from 1981. Its a little disjointed due to the odd sizes of article pages. This article noted that a five month study in 1977 showed that the Los Angeles Times had MORE FRONT PAGE weather stories than any other newspaper in the country!
The clouds were somewhat of a disappointment yesterday, not the stupendous photogenic day CM was expecting.
Maybe CM is total fraud, gets Big Oil funding and should be investigated by Rep. Grijalva as other weather folk are, like the great Prof. and National Academy of Sciences Fellow, Dr. Judy Curry, a friend, and about whom I say on a link to her blog here, and from this blog’s very beginning, “The only link you will need.” I said that because Judy2 is a top scientist, and is eminently fair in this polarized issue.
I am in real trouble! Will remove that link immediately1 before our very own “climate thought enforcer”, Demo Rep. Grijalva, AZ, finds it using a spy bot! No telling how far down the influence chain it will go, maybe all the way down to here, where there is virtually no influence!
Back to clouds…….
Only late in the day did the delicate patterns expected to happen ALL DAY appear, again, with iridescence, always nice to see.
The media, Bob, and our good NWS, of course, are all over the incoming rain in great detail. In fact, it will take you half a day to read all the warnings on this storm issued by our Tucson NWS.
So why duplicate existing information that might be only slightly different than the prevailing general consensus on the storm amounts, and then maybe be investigated for going against a consensus? No, not worth it. Best to be safe, not say things against The Machine. (OK, maybe overdoing it here.)
In the meantime, the upper low off southern Cal and Baja has fomented an extremely strong band of rain, now lying across SE Cal and the Colorado River Valley where dry locations like Blythe are getting more than an inch over the past 24 h. Same for northern Baja where some places are approaching 2-3 inches, great for them. You can see how the rain is piling up in those locations here. In sum, this is a fabulous storm for northern Mexico and the SW US, whether WE get our 0.915 inches, as foretold here, or not! Rejoice in the joy of others. Looking for an arcus cloud fronting the main rainband, too, that low hanging cloud in a line that tells you a windshift is coming. Still expecting, hoping, for thunder today to add to the wind and rain drama.
Also, the present cloud cover, as the trough ejects toward us, will deepen up and rain will form upwind and around here as that happens, so it won’t JUST be the eastward movement of the existing band. This means you might be surprised by rain if you’re outside hiking and think the band itself is hours away. Expecting rain to be in the area by mid-morning, certainly not later than noon, with the main blast (fronted by something akin to an arcus cloud) later in the day. OK, just checked the U of AZ mod run from 11 PM AST, and that is what it is saying as well! Wow.
Finally, if you care, yesterday’s clouds:
6:45 AM. Your sunrise color, thanks to a line of broken Cirrus spissatus. Jet stream Cirrus streak, as a matter of fact, moving along at about 110 mph.9:47 AM. Ruffle of Sc topped Mt. Lemmon, while strange clouds formed just upwind of them. These kinds of shapes suggest an inversion where the air resists further upward movement and a smoothing occurs at the top similar to a lenticular cloud. Photo taken at the Golder Ranch Dr. cattleguard. which really doesn’t work that well, as the neighbors below here will tell you.The 5 AM, March 1st, balloon sounding for TUS.9:53 AM. Looks like a crab with four pinchers. How funny.12:23 PM. Shredding tops of small Cumulus like this indicate that the air is very dry just above their tops, and the shreds racing off to the right, indicate how fast the wind increased as you went upward.2:58 PM. Something is changing here. Notice how the tops are bulging and not immediately being torn into shreds. The air was likely moistening above cloud tops, and the inversion holding the tops back, weakening as our storm gets a little closer.4:19 PM. A line of still larger Cumulus had formed to the west, indicating more moistening and “de-stabilization” of the air. However, the upper low was not advancing toward us any longer and no further development occurred as stagnated, ratcheting up its rainband over eastern Cal and western AZ. The TUS balloon sounding suggested tops were getting close to the normal ice-forming level here, -10 C, the slight inversion on the morning sounding at 13,000 feet above sea level, and the one likely to have caused those smooth morning clouds, was gone.6:07 PM. Just before sunset from near Oracle where we took mom for her BD. The heavier Cumulus clouds faded with the sun. They will arise today!
Below, just some pretty patterns observed later in the day. Click to see larger versions.
3:28 PM. Cirrocumulus began to appear.3:36 PM. Twisted, tortured Cirrus (fibratus?).3:50 PM. Another view of Cirrocumulus. Though these clouds are still composed of liquid droplets, the 5 PM TUS sounding suggests they were at about -30 C in temperature. It happens.4:00 PM. An incredibly complex array of Cirrocumulus overhead. Due to perspective, its about the only view that you can really see how complex the patterns are.4:20 PM. Some iridescence for you.6:00 PM. At Oracle, AZ.6:22 PM. Finally, from the “Not-taken-while-driving-since-that-would-be-crazy-though-it-looks-like-it-was” collection, this oddity. Looks like an high temperature aircraft contrail (aka, “APIP”) in the lower center. And the trail seems to shoot up into the cloud Altocumulus cloud layer (or down out of it). Have never seen that kind of aircraft track before since it looks so steep! “High temperature” here means that it formed at temperatures above about -35 C.
Whew, the end.
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1Not!!!!!! I thought this was a good read about this deplorable new stage of “climate thought enforcement” now in progress. It was brought to my attention by climate folk hero, friend, and big troublemaker, Mark Albright. Wow, maybe Mark will be investigated, too! Maybe I should excise his name….
2I remember, too, how cute she was when she worked my lab/office at the University of Washington in the mid-1980s, and thought about asking her out, to detract from a serious commentary here. She was a Penn State grad student, not a U of WA employee; still, to ask her out would have been untoward. A human commentary like this, one about feelings and things, help boost blog attendance.
1) Let yesterday morning’s color show speak for itself, just incredible, speaking for it anyway.
2) Please review the U of AZ time lapse film here to understand why it takes the biggest computer Fujitsu can build to calculate what the atmosphere is doing. Also reviewing this let’s you escape from the tedium about to be presented below.
3) Expect a similarly photogenic day today.
6:42 AM. First light, this incredible scene. Altoculumulus lenticularis downstream from Catalinas. Thought I would misspell Altocumulus to see if anyone is reading this. Sun seems to be coming up earlier and earlier….6:42 AM. Looking to the left or north of the lenticular….6:44 AM. That lenticular again, the bottom structure now highlighted.6:49 AM. What can you say? So pretty all around. Another lenticular was in progress to the main one.6:53 AM. If the scene wasn’t spectacular enough, a display of iridescence (rainbow colored area) then enhanced the original Ac len even more. It doesn’t get better than this and I hope you saw it “live.” I was just beside myself, taking too many photos, losing control, rationality.8:28 AM. Both lenticulars still in place, but now augmented by a layer of Altocumulus perlucidus (honey-combed look) and a scruff of low clouds that topped the Catalinas marking the invasion of a low level moist air. The feel of rain was in the air then, too.8:28 AM, the same time as the prior photo, but looking upwind over Oro Valley, toward Marana and beyond at a line of Stratocumulus, with Altocumulus perlucidus and patchy thin Cirrus above those. Even here, the scene seemed exceptional.9:41 AM. That Altocumulus deck began arriving overhead and you could see the little “heads” trailing ice crystals like comets with long tails. When the heads are gone, you’d call it Cirrus and never know how it got those fine strands. In the meantime, the Stratocumulus and Cumulus clouds were slowly getting deeper.1:19 PM. Looking over Catalinaville1: Stratocumulus was becoming the dominant cloud form. No ice, no precip, too warm at top; also, largest droplets in them below the Hocking-Jonas Threshold (30-40 microns in diameter) for collisions with coalescence to occur, if you care to learn things.3:42 PM. One of the many pretty scenes yesterday, these Altocu perlucidus, no ice. So, much warmer and lower than those trailing ice in the earlier photo.4:19 PM. Then, as the Stratocumulus filled in again, we got our late afternoon “light show”, those drifting spots of sun illuminating our mountains, though here our own Sutherland Heights subdivision, if that is what it is. So pretty.5:19 PM. Can’t be inside when these scenes are happening…. Have problem.6:13 PM. That sunset glow we see on our mountains every day, except a little more dramatic when dark clouds are overhead.6:19 PM. The day finished as gorgeous as it began as a clearing to the far west allowed the sun to light the bases of the overhead Stratocumulus layer.
The rain just ahead
Rain masses will be forming to west of Catalina today and will pound eastern Cal and western AZ for about 24 h before roaring in here tomorrow morning. Staying the course, best guess, from extremes of at least 0.33 to a max of 1.50 here, is 0.915 inches (the average of the worst and best case scenarios) here in “Catalinaville” as the total amount from this “hit” tomorrow and the showers afterwards into later Tuesday, as a second storm part comes by. Thunder tomorrow seems likely from this keyboard as the big rainband goes over.
During the passage of the rainband tomorrow, rainrates are likely to get up to an inch an hour, at least briefly, (this is the rate, NOT the duration) and typically, with several hours of moderate (0.1 to 0.3 inches per hour) to heavy rain (greater than 0.3 inches per hour) we should get a nice drenching.
The weather way ahead, 10 days or more
After a long dry spell following this upcoming rain, spaghetti is strongly indicating we have more troughiness in our future after the temporary dry spell!
Check it out, spaghetti connoisseurs2:
Valid at 5 PM AST, Saturday, March 11th. Note clustering of red and blue lines in trough off Cal.Valid at 5 PM, Sunday, March 15th. Southward bulging red lines, so many of them, indicate a very good chance of a trough here at that time. Blue lines, for a colder part of the jet stream, also tend in this direction, a good sign.
The spaghetti plots, taken together, indicate to the present Arthur that the chance of rain twixt spaghetti 1 and spaghetti 2 shown above is about 70%. It will be extremely FUN to see if this interpretation works out for rain between March 11-15th, at least one event anyway, to continue overusing that word.
The End, finally.
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1Didn’t Jimmy Buffet do a song about Catalinaville? Has a nice ring to it. Maybe we should think about it… Or maybe, in a vein similar to Carmel-by-the-Sea, “Catalina-by-the-Catalinas.”
2Remember, spaghetti is better than the model in the medium range forecasts that are presented based on the global data. Spaghetti is there to help you decide whether that model output is from the WRF-GFS looney bin or not. Here’s how:
Spaghetti is the result of DELIBERATE little errors put into the model when they start crunching the data to see how the forecast that you see on the maps could go wrong if there are errors in the data.
Of course, there are ALWAYS errors in the data! So, when the Fujitsu Computer DIvision made gigantically capable computers for us that were better than the ones we could make, ones that could do teraflops per second, we in the weather community could then run many permutations of the same model with itty-bitty errors in the initial data to see how the results changed (diverged) in the longer term.
Remember, too, in weather itty-bitty differences can add up to large ones in the longer term. So, when the model permutations with little errors cluster and DON’T diverge, it provides more confidence that the forecast storm, for example, is more likely to happen in that fuzzy forecast range of beyond 10 days or so. End of giant footnote.
In fact, the chance of MEASURABLE rain in Catalina is at least 100%, maybe as high as 300%, between 5 AM AST, Sunday, March 1st and 5 AM, AST, March 4th. Namely, its gonna happen.
Now, its not gonna rain that whole time, likely starting later in the day on the 1st. Pretty darn exciting to have a sure thing in the future! Check out this 4-panel presentation of maps from Enviro Can, I really like them:
Valid for Monday, March 2nd. Heavy rains foretold in western AZ by this time. Likely will be here by this time, too, though THIS model thinks the rain is still to the west.
Perhaps going farther than one reasonably should, the likely minimum amount will be 0.33 inches (10% chance of less) and top amount, gee, this situation has a big top, 1.50 inches, due to this trough’s deep reach into the sub-tropics, meaning it could pulling extra wet air toward us if everything works out in the “best” possible scenario. The best guess, between these two extremes is the average, or about 0.9 inches during our rainy spell. Should keep the washes flowing, though this one being colder than January’s tropical rains, should pile up lots of snow on top of Ms. Lemmon, so
Moving ahead to yesterday……
A pretty nice 0.09 inches fell yesterday morning in The Heights. “Nice”, because some model runs a few days in advance of this had no rain as a dry cold front went by.
When did the cold front pass?
9 AM yesterday, marked by a freshet from the NW with gusts to maybe 20 mph, with a falling temperature. Fell from 51 F to 42.x F by mid-morning, snow down to about 5,000 feet on Samaniego Ridge, too, though it melted almost immediately.
A push of wind like that virtually always builds a cloud above it, and yesterday was no exception. Here’ the cloud associated with that “freshet”:
8:31 AM. Wind shift line cloud shows up NW-NE of Catalina. Get ready!8:32 AM. Mini-rainbow appeared for just a moment.8:34 AM. Tiny holes in clouds produce pretty highlights on Eagle Crest as the windshift line cloud approaches.8:34 AM. Ditto above.9:03 AM. Windshift and line cloud pass over Sutherland Heights. Starting to rain here, though very little.9:03 AM. Close up of the bottom of the windshift line cloud.12:39 PM Post frontal passage quiet time with flattened clouds.1:28 PM/ Clouds swell up, first ice seen. Can you find it? More to north at this time.2:24 PM. Lots of pretty cloud “streets”, Cumulus clouds aligned in a line. Here’s a common one coming at you, one that comes off the Tortolita Mountains on Cumulus formation days with a westerly wind in the boundary layer (the layer between the ground and the tops of these clouds).3:19 PM. Walkin’ dogs now, but spotted trace of ice overhead in that SAME cloud street coming at me from the Tortolitas. Uh-oh. Do you see the trace of ice up there?3:21 PM. Few raindrops beginning to fall. Can you detect that bit of a rain haze on the left of center in this photo, out toward the Torts? Very hard to see, but there was an nearly invisible “shaft.”3:33 PM. Tiny snow shaft hangs from this same cloud line as it began to shift to the south and east. Can you find it?
Of course, the best part of days like yesterday is the play of the light and shadows on our mountains:
5:19 PM.5:58 PM. Stratocumulus clouds above the Charouleau Gap.
