This first one grumbled a bit, sent a bolt or two earthward last evening. Dropped a quarter inch on Ms. Lemmon. Hope you caught these brief scenes from two modest Cumulonimbus clouds:
7:05 PM.7:05 PM.7:31 PM. A different, very modest Cumulonimbus cloud that’s almost totally composed of ice (from this view). Note how the orange of the cloud is seen in some solar panels in the foreground. Pretty neat. Eyeball top, upper 20s, temp -20s.
Spurred from hibernation by these scenes somewhat like the flying ants we have around here by a good rain , AND by the amount of rain indicated in SE Arizona in the latest model run, the one based on the 5 PM AST global data. Here’s what happens in that run:
A tropical storm (what is likely to have been a Category 4 or 5 hurricane earlier in its lifetime) whizzes offshore of Baja in in 11 days or so, rather unusual for July, and lassos a humongous amount of clouds and rain, dragging them Arizonaward.
Here are the ark-like outputs from our best model, the “WRF-GFS”, as brought to you by IPS MeteoStar.
Rains move in on the night of the 19th-20th. This output showing the 12 h rain areas ending at 5 AM on the 19th.
The panels below are for every 12 h after the one above.
These heavy rains just go on and on, about three days worth in that run. Have NEVER seen so much rain predicted for this area, and while its too far away to have much confidence in it, its still worth considering as a possible event. You might want to perform some leak checks around the house just in case.
While the rainfall predicted above is somewhat moot, the likelihood of a strong hurricane in the Mexican Pacific is almost assured by our ensemble model runs (spaghetti plots). The signal is strong for one to form down there. Really, this kind of forecast is a remarkable thing that our models can do now days!
Such a hurricane will be fueled by the continuing extraordinary and vast areas of sea surface temperature anomalies; the entire eastern Pacific is aflame in unusually warm water. Check it out:
Sea surface temperature anomalies as of yesterday, July 9th.
As far as today’s weather goes, well, you can see those thin low clouds topping Ms. Lemmon this morning. Dewpoints continue high, around 60 F. And with a trough moving in, should be another breezy, pretty day with scattered Cumulonimbus clouds.
But, for a man’s forecast, not a little wispy one like the one above, see Bob’s site for an outstanding analysis! CMP (Cloud Maven Person) does not have the time to do a good, thorough one, if he could.
We received 0.08 inches here in “The Heights” for a third day with measurable rain in May already. 0.12 inches fell at the Bridge on Golder Ranch Dr. , while Saddlebrooke got up to a quarter of an inch (as estimated by CMP) in a tiny streak of clouds that erupted into shallow Cumulonimbus clouds, anvils and all yesterday afternoon between 4:30 and 5:30 PM. It was pretty much all over by 6:00 PM, those shower clouds passing off toward Mammoth.
No rain was reported at mountain sites, to give you an idea of how localized that was, localized practically to Basha’s Market parking lot, Sutherland Heights’ Equestrian Trail Road, and Saddlebrooke’s Acacia Drive, to exaggerate some.
The astounding aspect of a tiny line of showers that suddenly erupted over and a little downwind of Catalina was that it was EXACTLY predicted in the University of Arizona’s 5 AM AST model run yesterday morning, one whose results are available by mid-morning! So, there would have been a few hours notice of possible rain here in Catalina.
There is no rain predicted in that model run anywhere else except in extreme NW Arizona, just that tiny ribbon of rain right over us, and the U of AZ “Beowulf Cluster” weather calculator got it right.
However, unless you were in the right spot, you might not have even known that it rained, the shower streak was so narrow.
Below, the astoundingly accurate predictions for 3, 4, and 5 PM for that model run from yesterday morning. No rain whatsoever is shown at 3 PM, as you will see.
To be “fair”, NO RAIN was predicted anywhere NEAR Catalina by that same model crunching the data from 5 PM AST the evening before our little rain event, leading CMP to be a little asleep at the wheel yesterday morning, no blog.
Some cloud shots before and as this predicted (or unpredicted, as the case may be) rain began to happen. Of course, if you want to go to the movies and see this, go here, from the U of AZ: Yesterday’s cloud movie
3:23 PM. Looking upwind. Nada going on, clouds to shallow for ice.4:04 PM. Hmmmm. Clouds definitely fattening up upwind of us in a nice cloud street from upwind of and over Pusch Ridge to Catalina. Nice scene, anyway, even if nothing happens.4:12 PM. Cumulus clouds are looking to gather down there at the corner of Pusch Ridge and Oracle Road, Huh. And they’re heading in this direction. Can ice really form in these guys today?4:23 PM. Clouds over and downwind of Pusch Ridge continuing to gather while heading toward Catalina. Looking for ice now or virga, but don’t see any anywhere.4:33 PM. Ice begins to show up in even modest clouds! And it started to show up everywhere in the form of virga. But then then the virga became thin shafts all the way to the ground. Cloud Maven Person is beside himself, but must go indoors for a social engagement! Those of you who fancy yourselves as Cloud Maven Juniors, should have recorded this sighting of “first ice” in your cloud diaries for yesterday.Also at 4:33 PM. Ice is now readily visible in that Cumulus mediocris massing upwind of Catalina and is not about over the south part of the Catalina CDP (“Census Designated Place” that might one day be absorbed by Oro Valley, rumour has it.)4:41 PM. Just minutes before the first drops fall in Saddlebrooke, and CMP’s last photo of this incoming masterpiece of weather forecasting and little rain band; he can no longer comfortably jump up from dining room table in mid-conversation to say he has to pee again whilst actually taking a photo. You can only say you have to pee so many times in 10 minutes and still have your credibility intact. But, how can you say repeatedly, “I have to go look at some clouds?”, so I can’t hear the rest of your quite interesting story……” Really came down for a couple of minutes several times there in Saddlebrooke between a quarter of five and 6 PM as one little raining cloud formed after another in this cloud stream.
Below, sat view of this cloud streamer with radar, from IPS MeteoStar. The image below is at the same time as the last photo above:
Satellite and radar imagery for 4:40 PM AST. Note the many lines of clouds running almost due south to north into SE AZ from Mexico.
Here some more cloud stuff from the sounding launched at the U of AZ around 3:30 PM AST.
The TUS balloon sounding (“rawinsonde”) for yesterday afternoon. Looks like most tops were dabbling with the ice forming temperature of -10 C, but the sounding suggests that somewhat deeper tops could easily have arisen (and did!). Interestingly, the model “knows” when ice forms, and it must have “known” that the ice-forming temperature was going to be surpassed in that little cloud line coming off Pusch Ridge. Astounding, for the Nth time. Bases were pretty cold, 0 C (32 F).
Here’s a diagram of when ice forms in the type of clouds we mostly have in Arizona, “continental” ones with high droplet concentrations, and when ice should form in them. As you can see, ice should form in them soon after the top temperature gets colder than 10 C WHEN the base temperature is about what it was yesterday.
From a survey of the onset of ice formation in continental clouds by Rangno and Hobbs (1995)1
“CMP” is not mentioning it at all, but yesterday was another kind of mucked up sky, not a Catalina postcard sky, with lots of aerosols making the sky a whitish-blue, the lower aerosol stuff again from Mexico, but there was also a layer far above the cloud tops, likely a long-range transport event from thousands of miles away.
This higher haze layer still seems to be around if you look toward the horizons right now (5:59 AM).
We’ll be between two jet streams today, kind of a jet stream sandwich, and the stronger one is now approaching from the northwest with that mega upper low over Cal. That means no rain today, subsidence rules, though we’ll have small, non-ice producing Cumulus, and likely some Altocumulus lenticulars, maybe a Cirrocumulus patch here and there. Should be a pretty nice day for cloud photos, haze aside.
The best chance for rain is still after midnight tonight into mid-day tomorrow as the core of the stronger jet stream goes just about over us. Still thinking a tenth of an inch will occur here, though mod run from the U of AZ at 5 PM completely dry. A little snow likely on Ms. Mt. Lemmon, too!
After last evening’s surprisingly heavy rain, we have now met our average for May for Catalina, having received 0.47 inches of rain over the past 24 h, some 0.36 inches during some house-shaking thunderclaps last evening.
Below are the 24 h local totals, ending at 4 AM today from the Pima County ALERT gauges rolling archive , these totals pretty much capturing all of our beautiful storm:
Gauge Location ID# —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.63 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.83 Oracle Ranger Station approximately 0.5 mi SW of Oracle 1040 0.55 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.75 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.79 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 0.39 Cargodera Canyon NE corner of Catalina State Park 1080 0.63 CDO @ Rancho Solano CDO Wash NE of Saddlebrooke 1100 0.35 CDO @ Golder Rd CSO Wash at Golder Ranch Dr
Santa Catalina Mountains 1030 1.18 Oracle Ridge Oracle Ridge, 1.5 mi N of Rice Peak 1090 0.35 Mt. Lemmon Mount Lemmon 1110 1.34 CDO @ Coronado Camp CDO Wash 0.3 mi S of Coronado, 1130 0.83 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.79 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.24 White Tail Catalina Hwy 0.8 mi W of Palisade RS 2280 0.24 Green Mountain Green Mountain 2290 0.12 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
For more rainfall info, go here and here. And here to the USGS, too, not to mention the NWS rainfall tables. Too bad they can’t all be in one gigantic table!
The clouds and weather just ahead
A little cold morning rain, and even snow on The Lemmon, is looking likely for Saturday morning. Presently, the core of the jet stream at 500 millibars or around 18,000 feet associated with a mighty upper cold low that sits on Arizona on Saturday is forecast to be south of us (as was yesterday’s jet), a pretty black and white discriminator for cool season (Oct-May) rain here.
However, if that jet core around the low does not circumscribe TUS, you can forget rain. From IPS MeteoStar, this rendering of the upper level configuration for Saturday morning, showing that it WILL circumscribe TUS:
The 500 mb heights and winds predicted for 5 AM AST, Saturday morning, May 10th. Its gonna a cool Mom’s Day, too. One would expect rain here in Catalina with this configuration. Note how max winds are in a band well south of us. That banding circumscribes the deeper parts of the Pacific moisture that came in with this trough. This rendering is from the global crunch of data taken at about 5 PM AST, yesterday evening. These runs are updated every six hours.
In the meantime, “troughiness” today, tomorrow and Thursday, with secondary jet stream to south of us, will give us some more photogenic high-based Cumulus, maybe with some with virga in the afternoons. Today, as our upper low says goodbye, subsiding air is supposed to keep clouds from attaining tops high and cold enough to form ice. So, no rain today.
Yesterday’s clouds (going deep, as in pedantically)
There were some great scenes yesterday, summer-like ones, odd for May here, with massive rainshafts as the cloud bases lowered, reflected a huge jump in surface dewpoints to summer-like values in the mid-50s. Cloud bases yesterday morning, riding the tops of Samaniego Ridge, were near 7 C, compared with -5 C the afternoon before.
This warming of cloud bases greases the precipitation “wheel” since clouds with warm bases are be able to rain easier than ones with cold bases (say, near or at below freezing temperatures). Droplet sizes have to be larger at any given level above cloud base compared to the clouds of the day before since more moisture is forming in those updrafts at the higher base temperature. And, oddly, the larger the droplets, the higher the temperature at which ice can begin forming in clouds. And when ice forms, snow, then rain, come out the bottom.
To go on too long on this in covering all rain possibilities for yesterday, a base temperature of 7 C here is on the edge of being able to produce droplets big enough so that some begin colliding with one another and sticking together so that drizzle, then raindrops can form, a couple to a few thousand feet above cloud base, and those sizes of drops can really accelerate the formation of ice and then rain out the bottom. Are there any readers left? I doubt it.
Let us go even deeper…. It was hazy, smoky looking yesterday most of the morning, even when some good thunderstorms formed. So what? Well, smoke is bad for storms. Remember when it was reported by Warner and and the U of Arizona’s own Sean Twomey (1967) that sugarcane burning made it stop raining downwind from those fires in Australia? That effect has been verified in satellite measurements by cloud seeding nemesis, Danny Rosenfeld2 of the HUJ in Science a few years ago.
Well, too much smoke can choke droplet sizes down and inhibit the formation of rain by collisions, and delay the formation of ice. And so we had that counter effect of smoke from somewhere, maybe LA this time since it was in the boundary layer, not aloft like that smoke layer from Asia was a couple of weeks ago.
So, cloud microstructurally-spekaing, it was an especially interesting day, one, if he were cloud maven person, wishes he would have had an aircraft to sample them.
But let us look now and see what all the fuss is about:
5:40 AM. Dewpoints in the 50s; Stratocumulus clouds top Samaniego Ridge!6:41 AM. Soft-serve Cumulonimbus forms over west Tucson, Oro Valley. Icy top looks like its comprised of needles and hollow sheaths to me, ice that forms at relatively high temperatures for ice formation, higher than -10 C.6:42 AM. In the meantime, drama over Oro Valley to the west and north of Catalina as a deeper cloud unloads. Thunder, too.7:19 AM. Haze and rain. This was a pretty astounding sight, so much haze/smoke in the rain as evidenced by these intense crepuscular rays.8:19 AM. A real summer-looking sky on a big rain day. Frequent lightning was emitted by this behemoth that went on to pound Saddlebrooke.8:37 AM. Unusually strong May thunderstorm pounds Saddlebrooke.
3:42 PM. In spite of lots of convection and scattered Cumulonimbus clouds, the sky remained almost an eastern whitish due to smoke, which I will blame on southern California, absent any facts or investigation. No time.
6:59 PM. Our major evening rain and thunderstorms were developing upstream.
2Rosenfeld a “nemesis?” See the references and discussion below for kind of an interesting science story aside….
Rangno, A. L., and P. V. Hobbs, 1997a: Reply to Rosenfeld. J. Appl. Meteor., 36, 272-276, and…..
Rangno, A. L., and P. V. Hobbs, 1997b: Comprehensive Reply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp.
With the publication of voluminous (en toto) commentaries/critiques in 1997 by a few of our peers, but mainly by Danny Rosenfeld of the Hebrew University of Jerusalem, that concerned our 1995 paper reanalyzing the Israeli randomized experiments, yours truly and Peter V. Hobbs, had attained, according the the Technical Editor of the Journal, the status of having become the most criticized meteorologists in the history of weather–well, in the history of the Amer. Meteor. Soc. journals, anyway! How fun is that? Its fun.
Our findings, that the two benchmark Israeli randomized cloud seeding experiments conducted in the 1960s and 1970s were largely misperceptions of cloud seeding effects due to storm biases on seeded days, were independently verified in peer-reviewed publications by researchers at Tel Aviv University some many years later.
Operational cloud seeding has ended in Israel in favor of more fruitful avenues for obtaining the water they so badly need.
Well, it could have been more I suppose; some areas of central and northern Arizona have gotten between a half an inch and an inch of rain overnight. Nevertheless, it was great that a passing thunderstorms (“TSTMS” in weather texting) happened here in Sutherland Heights overnight, fabulous, really. Dropped 0.28 inches on Mt. Lemmon, btw.
More scattered showers, and maybe a thunderstorm or two, should develop today. Keep cameras well-oiled for some great cloud scenes.
Yesterday’s clouds
8:04 AM. In the beginning….. Unlike the day before, our shower clouds didn’t move in, but rather had to start from something akin to poppy seeds. Still water highlights on Samaniego Ridge.12:06 PM. Cumulus increase in size and number. No ice yet.2:14 PM. First minute amount of ice begins to show up underneath downstream cloud portions. You’ll have to be awfully good to find it!3:37 PM. Ice, and now well-developed virga, is plentiful in many of these shallow clouds.4:00 PM. Numerous light rainshowers and glaciating shallow Cumulus clouds dot the horizon to the SW,6:58 PM. Shows the fine structure of virga, trails that can be only 5-20 meters wide as they drop out of a cloud. Strands like this are usually soft hail, or what we call “graupel.” Snow virga like this tells you that cloud bases are well below freezing, and on a warm day are very high above the ground. Yesterday’s late afternoon cloud bases were up around 14 thousand feet above sea level, at about -5 C (23 F). The virga melted into raindrops behind the cloud below it.
7:04 PM. A light rainshower advances on Catalina. Where the pinkness disappears below the main cloud base is where the snow virga is melting into less visible raindrops.7:06 PM. Another fiery sunset highlight involving a Cumulonimbus cloud. Cloud tops were beginning to deepen noticeably by this time.
Well, let us define “cool”….that is, cool for Catalina in May; that is #2, below normal temperatures.
What led to this thought?
I was gasping when I saw this from last night’s NOAA spaghetti factory, as you will as well, and decided I would have to say something about it.
Valid on the 17th of May, 5 PM AST. Wow! And with a persistent pattern like this (red lines dipping so far toward the Equator (which is that dashed line that goes through Hawaii and Mexico1), which we now seem to be in following our little warm up, now in gradual retreat, big flooding will occur in the central and southern Plains States, the kind that makes the 5 o’clock news (or is it 6 o’clock?). Wow.
Pretty unbelievable.
What does it mean for Catalinans: a personal view?
Oh, big windy episodes from time to time during the month, good chance for above normal rain for Catalina, and probably most interesting, the late spring ovenly weather that we like to brag about how we get through wherein so many of our Catalinans and “Tucsonians” flee to the high country, or to Michigan, is held at bay by recurring puddles of cold air up top.
That’s my prediction for May, which has already been ludicrously posted in a prior post many days ago. We might look back at May some day to see how this incredibly unprofessional forecast for a whole month based on one spaghetti run worked out.
If you want professionalism in medium range weather forecasting, then get the hell off this site now! Maybe you’re the kind of person that would rather see a forecast from the NOAA Climate Prediction Center for Catalina and environs. If so, you don’t belong here.
But lets see what they say, anyway for May, then for the whole of mid-April through July…..to add that bit of uncharacteristic professionalism to this site. See maps below:
Looks like they’re pretty clueless about what the temperature’s going to be like here for May–“EC” means equal chances for below normal OR above normal. So, they could be right no matter WHAT happens! But not me. I think Cal is goona be wrong, too; below normal, not above normal temps. Its great when you can just type things like that!
The Big Boys don’t really know what’s going to happen with the May rain here, either, since we are also in an “EC” area. But boy, look at the May rain foretold for the Plains! Looks like a great place to spend May! OKC, maybe. WCWS begins at the end of May, amateurism at its best.
But, at the same time, for the whole of mid-April through the end of July, the Big Boys at the CPC are expecting the drought in areas of the central southern Plains States to persist or intensify–see dark brown areas below.
It will be interesting, being serious for the moment, to see how these predictions, seemingly in some conflict, work out. Note that in the longer view below, Catalina is in an area where drought “persists or intensifies”, even through JULY! Egad.
Nice clouds yesterday….
6:00 AM. Mamma to the S, pretty big mamma. Indicates unstable conditions aloft, maybe some showers will reach the ground.10:01 AM. Heavy vIrga pummels air above Catalina/Saddlebrooke.4:20 PM. High-based Cumulonimbus clouds approached from the south promising blasts of wind, maybe a few drops. No drops here, though.6:47 PM. Cumulonimbus and rain reaching the ground passed to the W-NW of Catalina. Darn.7:04 PM. The moon AND pink virga in the SAME photo! Yours today for $900. Trying to follow through on an Atlantic Mag article, “Blogging for Dollars.” That would be great, but it hasn’t happened yet.7:09 PM. Your Catalina sunset, May 2nd, 2015, Altocumulus castellanus with Cumulonimbus capillatus, along with a Cal palm silhouette.
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Yeah, I saw that report that America’s kids don’t know much about geography, so we’re just checking here to see how bad it really is by suggesting that the Equator goes over the Hawaian Islands (hahaha). But, maybe, they’re really the Galapagos Islands… Am I being too subtle? Sam Cook once pointed out about himself, “Don’t know much about geography”…in his song, “What a wonderful world it would be“. it was a movement that apparently caught on.
Clouds got more enthusiastic than expected here yesterday, reaching sizes big enough to produce light rainshowers to the NE of Catalina, and THUNDER just after 6 PM up toward Oracle town! Nice. Looks like a small Cumulus, postcard day today in Catalina. Cloud tops marginal for ice, holding around -10 C, capped by subsiding, dry air. (Except for the light showers this morning between 7 and 9 AM; this note added at 7:32 AM when I saw a shower developing to the west over Oro Valley!) This, from the U of AZ model. Since the air is colder aloft to the N today, ice will likely be seen in some clouds up thataway.
7:26 AM, looking toward Samaniego Ridge. Water still flows down from the upper reaches of Samaniego Ridge from the winter rains. You’ll have to click on the image to really see this water.1:22 PM. Small Cumulus get underway.
2:25 PM. While Cumulus occasionally filled in, they weren’t getting any deeper. No ice visible at this time.4:11 PM. There was plenty of ice around at this time, but most of it, as shown here above and to the left of the right most light standard, ejected out the downstream end of the clouds. This meant that the ice crystals had no chance to grow inside a cloud, but were thrown out into dry air and evaporated. Wider and taller clouds were needed for even decent virga to happen.5:38 PM. Those deeper and wider clouds began to develop. Here a sprinkle or light rain shower reaches the ground toward the town of Oracle. Fifteen minutes later, thunder was even heard coming from this complex.6:45 PM. The thunderstorm that occurred near or over the town of Oracle weakens and recedes. For a time it appeared building Cu overhead of Catalina might produce a sprinkle, but no.6:50 PM. The day ends quietly.
After a sumptuous day of Cumulus and Cumulonimbus clouds yesterday, a long period mostly devoid of any Cumulus clouds is expected to begin after today.
Cumulus congestus and Cumulonimbus clouds rose early and often to the north of Catalina, but did not launch off of the Catalinas as expected with a minor exception that only the best of the CMJs would have noticed. If you want to see the whole day, devoid of blabber, take a gander at the U of AZ Weather Department time lapse film here. Very summer-looking video yesterday with the Cu moving from the SE as we see on most summer rain season days.
9:30 AM. Heavy Cumulus clouds erupt on the high terrain NNW-NE of Catalina.9:53 AM. Cumulus over the Catalinas are beginning to shoot small turrets up.
10:45 AM. Lookin’ good for a Cb launch at this point, especially with all the Cbs on the N horizon by this time, indicating unusually fertile grounds for a big cloud growth on the Catalinas.
1:58 PM. As Bob Dylan wrote, “You Ain’t Goin’ Nowhere”, you Cumulus clouds. But why? Too dry aloft right here over Catalina, and less so to the north? Probably.
The wait for an explosive development over or near the Catalinas went on and on with nothing happening. In the meantime, Cumulonimbus clouds were getting closer and closer to the north of us.
2:22 PM. As close as they got. Cumulonimbus calvus (“bald”) top about 20 miles N of Catalina protrudes above the lane divider line on Oracle Road.3:25 PM. One pitiful Cumulus congestus cloud rose up to ice-forming levels, glaciated and died. Its head passing almost directly over the house, as you will see. Here, no ice is evident externally, but its in there if you could judge how much higher this cloud was than those that preceded it.3:30 PM. Dissicated by the surrounding dry air, that poor turret dies, leaving visual evidence of the ice inside. Can you see it? Anyone under this would have felt a few drops of rain at this point.3:33 PM. Only three minutes later, death is almost complete, leaving more visual evidence of the ice that had been inside it. The cloud in the foreground obscures the highest part of the turret that shot up so much higher than its nearby brethren. Feeling pretty sad here.3:33 PM. Life-size close up so that you can see what I am trying to describe. The faint veil between the cloud shreds is composed of ice. The shreds are droplet clouds, but also with some ice in them.3:42 PM. The icy top of that lonely turret finally shows.3:42 PM. Close up, just about looking straight up.
3:43 PM. Frame from the U of AZ time lapse camera showing icy top over Catalina. Was it the “Little White Cloud That Cried?”, produced a few raindrops? I think so, since you really have to have ice nearly all the time around these parts to get rain. I’ve spent a LOT of time on this cloud. Maybe its because we won’t see anything like this for so long now.
While the rain at the beginning of April has disappeared altogether in recent model runs (ones after 11 AM AST yesterday), it will likely return in the future. Also, mods now think some rain might occur a week from now.
Litterfolk continue to prefer Bud Light cans and bottles over craft beers. While its interesting to make these surveys, CMP reminds readers, “Litter responsibly; in a receptacle.”
The trash you see here was collected during a single trip to the Sutherland Wash and back.
The Sutherland Wash Flow Report
A little water has resumed flowing in the Sutherland Wash hereabouts due to our recent rain:
The Sutherland Wash yesterday near the Baby Jesus Trail Head. Dog head also included.
The Cottonwoods Blowdown Report
The wind damage below was confined to an area only about 100 yards wide, and at the bottom of a small canyon leading down from Samaniego Ridge. Once suspects that a narrow microburst, some supergust, hit just in here as a rivulet of air collapsed down from the east-northeast after having gone over the mountains. It was likely further funneled by that little canyon and blasted these poor trees.
Note shoe size in lower left of photo.
Yesterday’s clouds report
Cumulus got off to an early start, a line of Cumulonimbus to the north providing a hint of what was to come when the sun came out.
7:06 AM. Cumulonimbus line the northern horizon.7:07 AM. An interesting set of very narrow shadows appeared briefly. The darker one might have been due to a young contrail. They seem too narrow to have been caused by cloud turrets.10:34 AM. Cumulus congestus clouds arose early and often on the Catalinas, becoming Cumulonimbus clouds later in the afternoon.12:07 PM. Some Cumulus congestus clouds sported the rarely seen “pileus” cap, suggesting stronger than usual updrafts pushing moist air above the top upward slightly, just enough to form a sliver of cloud.12:07 PM.12:54 PM. Before long, 47 minutes actually, big complexes of Cumulonimbus capillatus had formed to the north, and distant SW of Catalina.1:47 PM. While pretty, but this expansive Cumulonimbus capillatus incus (has an anvil), pointed to a potential rain-inhibiting problem: perhaps the exuberant convection would lead to an over-anvilated sky? Yes, it became a concern, I’m sure to all of us. Cumulus cloud killing anvilation.3:54 PM. While lightning forked in distant rainshafts, over-anvilation pretty much terminated any chance of rain in Catalina due to Cumulus buildups. The anvil debris clouds are termed, “Altostratus opacus cumulonimbogenitus.” Only clashing winds due to outflows from showers could possibly force rain now.4:43 PM. Clashing shower winds (SW in Catalina, NE towards Oracle) did produce a large final shower in the area. That lower cloud on the left side marks the area above and a little behind outflowing NE winds. Sadly, that wind push from the NE, one that could have launched a big shower here, fizzled out.
The weather ahead and WAY ahead report
More pretty Cumulus clouds today, likely some will reach Cumulonimbus stage (develop ice) and shower here and there. Flow will be off the Cat Mountains and so we here in Catalinaland are a little more elgible for a shower building on those mountains and drifting this way.
WAY ahead?
The models continue to occasionally produce a very heavy rainstorm in southern AZ on or about April Fool’s Day, once again appearing yesterday on the 18 Z (11 AM AST) run. See below, a really pretty astounding prediction again. This system comes from deep in the Tropics, so deep you wonder if it might have some hair from a giant Galapagos tortoise with it. It comes and goes in the models, but there is continuing modest support for a low latitude trough to affect Arizona in the “ensemble” outputs, or “spaghetti” plots.
The End
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1“The Cottonwoods” is a local name given to a portion of the Sutherland Wash next to the Baby Jesus Trail Head. It appears on most trail maps, and is a popular spot for underage drinking parties on weekends.
Happened around noon yesterday. I could see it from here that the shaft consisted of graupel mixed with some rain. Nice video of this exceptionalism-of-the-day event here from the U of AZ.
Its interesting to me, and to you, too, most likely, was that yesterday it was asserted here that there would be no ice in the “small” Cumulus clouds that were expected to form during the day. And yet we had a momentary Cumulonimbus cloud with a ton of ice and a graupel/rain/snow shaft! Huh.
In related1 distractive headlines:
Fields of gold erupt in Catalina!
Hours: 10 AM to 3 PM, M-S, otherwise closed. Why do they do that? You won’t find the answer here, so move along now…
4:00 PM yesterday, on hills west of Spirit Dog Ranch. Numerous poppy flourishes in this area. On horseback,, Nora Bowers, co-author of the popular guide, Wildflowers of Arizona. Those poppy blossoms were pretty much closed here. You really should get out and see them if you can. Well, worth it.
Rasslin’ Dogs!
“Emma” border collie, bottom, “Banjo”, border terrier mix of some kind, top. 2-day old distractive photo. More distraction. Few readers will likely go farther than this….
Yesterday’s clouds and explanations
8:22 AM. Altocumulus, bases about 14, 000 feet above sea level, or about 11,000 feet above the ground here in Catalina. The temperature at cloud top, via the TUS balloon sounding, was about -15 C (5 F), pretty cold for not having some virga or ice showing. It happens. There could be several reasons: Lack of ice nuclei in that layer? Tiny droplets, ones that resist freezing more than larger cloud drops? Lack of mixing with very dry air above cloud top (it was moist all the way up to Cirrus levels))? Mixing in very dry air at cloud top can lower the temperature of a drop a few degrees before it disappears completely, thus increasing the chance that it will freeze. That last effect is mostly operating in Cumulus clouds whose tops can penetrate relatively far into very dry layers. So, once again, we have no real answers, or maybe, all of them. It is worth noting that going to -15 C here and no ice in a Cumulus cloud is a virtually unknown occurrence, one that speaks to ice nuclei, those specks of mineral dirt that are known to cause ice to form in clouds, like kaolinite, etc. originating in the boundary layer/dirt interface being a primary culprit.
10:49 AM. In fact (!), “small” Cumulus clouds DID form yesterday, hold the ice. Quite a forecasting triumph.10:51 AM. While small Cumulus clouds pervaded the sky, there was an exception; the usual cloud street that forms off the Tortolita Mountains was trailing over Catalina and those clouds in it were at least of mediocris size (likely a km deep or so), and due to the low freezing level yesterday, getting close to the ice-forming level for Cumulus clouds here of around -10 C (14 F). Was actually outside, as you probably were, too, as it passed over, shifting gradually to the south, hoping for a drop so’s I could report a trace of rain today. “Great weather folk don’t miss traces!” (Dry-fit tee shirt in preparation….)11:00 AM. I want to keep reminding you of the prevalence of small, “docile” Cumulus clouds (ignore large dark cloud shadow at left). Just trying to balance out the cloud day picture the way media balances things out, regardless of whether they are Democrats or Republicans.
11:52 AM. Graupel begins to fall from a Cumulus congestus just beyond Pusch Ridge. It would be hard to describe the magnitude of the embarrassment I began to feel having stated that there would be no ice. I realized I had been careless as a forecaster, not really looked hard enough at the conditions, the lapse rates. It was truly humiliating to see this happen. Oh, in case you can’t see anything, the next photo is a blow of this humiliation as it began to take place.11:58 AM. Picture of graupel particles emitting from a cloud from 10 miles away. Note fine strands, a sure sign of graupel especially on day with a low freezing level and cloud bases at below freezing temperatures. Note too, ice is not visible at cloud top, something that indicated an abundance of droplets over ice crystals in the cloud, the conditions that lead to the rapid formation of graupel (soft hail).
12:10 PM. More humiliation and graupel; a forecasting disaster is in progress for all to see!
12:17 PM. Turret at left side, under fragment, appeared to be softening to the look of an icy composition that all would recognize immediately, but external ice composition not apparent yet. Note the “harder”, more cauliflower look of the turret on the right half of the photo, indicating an all liquid external composition. Graupel was forming inside that right half, though.
12:29 PM. Total icy humiliation. The “cotton candy” transition of the prior turret to “Mr. Frosty” (left of center) was complete for all to see. Looking toward Catalina, I could almost hear the laughter, “Calls himself a ‘cloud-maven’, said there wouldn’t be any ice today, and look at all that ice! What joke!” Now that the turret has become a modest Cumulonimbus, likely completely glaciated, the precipitation falling would be snowflakes (not graupel since the liquid water droplets are gone inside it) melting into rain farther down.
4:21 PM. The clouds returned to their former “small”, ice-less, sizes for the rest of the day after the humiliating exception.
6:18 PM. Revealed in yesterday’s near cloudless sunset, undulations in the ever present high altitude haze layers that circumscribe our planet. Layers like this, that are featureless except for the revealing waves causing the undulations, are extremely old, days, and are often reffered to as long range transport events because they likely traveled thousands of miles before arriving over Arizona. They are likely to be composed of old, old contrail emissions, emissions that have worked their way up in the atmosphere from over heated land surfaces, distant forest fires, and so on.
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1Its not really related but sounds like something that should be said.
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!
