7:35 PM. Curtains of ice droop down from heavy patches of Cirrus spissatus producing an outstanding sunset last evening. Hope you saw it. What kind of ice? Likely “bullet rosette” ice crystals are the ones falling out.The complex ice crystal called a “bullet rosette” for some reason as imaged at 130 mph by an instrument (Cloud Particle Imager) on the University of Washington’s research aircraft high over Barrow, AK. These were at the bottom of Altostratus (thick ice) clouds around 23, 000 feet above sea level. Tops were about 32,000 feet, and was thick enough to produce a gray overcast. The CPI was designed and built by Paul Lawson, a friend who was a starting defensive back on the Michigan State Spartan’s National Champion fubbal team of 1966 or 1967. He formed, and is still the CEO, of Stratton Park Engineering Company, one that makes a lot of high end instrumentation for imaging cloud particles. Likes to meditate, too; just kind of sits there for hours on end like a piece of pottery. I don’t get it. Maybe its related to concussions he might have gotten.
Action shot of the University of Washington Convair-580 research aircraft in flight, in case you wanted to see that. My job was to stand on a little stool (hmmmm, that doesn’t sound right) so my head would be high enough and fit in that little dome and say things about clouds, which as here, was usually too much. Pretty cool, eh?
Wasting time here, filling in with filler material1 since there’s no real chance of rain, though, as usual, pretty clouds and maybe some real nice sunrises llike this morning’s and sunsets. That’s OK. We’ll get by until the Big Boys arrive, those Cumulonimbus clouds of summer, with all their splendor and drama. As reported in the media, a better than average rain season is being foretold by the Climate Prediction Center. How nice is that?
Small Cu today, maybe a CB top way off toward the S or SE…. Have some nice Altocu now, splattered around. No rain in WRF-GFS hereabouts for two weeks, but, as we know over and over again, they can be VERY wrong in that longer view!
The End.
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1Remember when newspapers had “fillers”, interesting little facts punctuating the pages where the columns and such left little spaces after being laid out? They had some fascinating material in them, such as that a certain spider’s web strand, if the diameter of a garden hose, could support TWO 747 jets! (True!)
Looks pretty good…. Two completely different computer models show tropical moisture getting into Arizona in about 5-6 days a resulting preview of the summer rain season. You can find quite a bit of “green pixies” (areas of rain denoted by areas of green pixels) in Arizona here from IPS Meteostar’s rendition of our best model, the WRF-GFS. And, the Smoking Canadians have rain in our area in their model, too. This is going to be the best chance for measurable rain in Catalina since early April!
In the US model linked to above, you can also see the residual low pressure center from today’s Hurricane “Crissy” moving up the coast of Baja Cal in five days. Finally, could we have a month with above normal rain after not having one since November 2013 (or was it 2012?) Might happen, after all we deserve it. So, I will now predict that June will be above normal in rain in Catalina, AZ.
You can keep track of Crissy here. I will be tracking Crissy, that’s for sure.
Below, an example of rain (with drizzle) in case you’ve forgotten what it looks like in a research aircraft with laser beam imagery of all the stuff you’re flying through:
Rain (and drizzle drops) as seen by aircraft instrumentation, arranged in order of small to larger, left to right. The horizontal lines are just about a millimeter apart, so the biggest drops here, one that aren’t breaking up, are about two millimeters in diameter. Drizzle drops, as CMJs know, are those between 0.2 to 0.5 millimeters in diameter, so there are a lot of those. BTW, these were collected while the aircraft was flying at about 160 knots (80 meters per second). Pretty amazing you can image these drops as they go by so fast!
The discerning reader will want to know what spaghetti sez; what are the chances that the steering winds in the middle of the troposphere will steer Crissy toward us as it moves around off’n Mexico. Will those steering winds help Crissy’s moisture get into Arizona and over Catalina?
We seek help from spaghetti and, indeed, the spaghetti shown below is “supportive”, that is, it shows that the “planets are lining up” for rain here, as an astrologer might say, those people we look to for personal guidance in everyday matters; whose forecasts are so important no newspaper can go without them without causing an uproar on the part of their readers.
See writing on figure below for some additional weather interpretation.
Valid for 5 PM AST June 16th. Those red lines suggest that Crissy’s remains (RIP) might indeed be directed at eastern Arizona! Big trough for this time of year foretold along West Coast with high confidence, as indicated by “bunching lines”, perfect for drawing tropical storms northward into the Southwest US. If not us, then those dry areas of New Mexico and west Texas virtually guaranteed for some tropical air.
Yesterday’s clouds
10:53 AM. Mostly Cirrus uncinus, bisected by a contrail.2:38 PM. Cumulus humilis and fractus boiled up out of 100 F plus air at the surface. Tops warmer than -10 C, so no ice, just those thin patches of Cirrus on top.3:08 PM. Cirrocumulus atop Cumulus fractus clouds.
Nice Altocumulus around this morning, but moisture is really confined to that level, not deep enough for rain at the ground. The Cumulus that form this afternoon will have bases around 14,000 to 15,000 feet above the ground. They should be deeper than yesterday, and so ice is likely to form in the larger ones (and we hope that you will log that in your daily cloud diary), but only tantalizing virga is likely, maybe with some brief windy periods near them.
Pinching the old Consumer Reports segment, “Quotes without Comment” page from decades ago, for a title. But after that title, I changed my mind and will write a coupla captions.
What drought? This gigantic weed popped up in the middle of an agave plant recently. Spurted up about two feet a day in the backyard! Proabably some kind of wild asparagus. Must be over-watering this year since it sure as hell didn’t come up last year. Wonder if its edible? Cirrus clouds form the backdrop.
Sunset.Morning Cirrus.Cirrus patch trying to be Altocumulus perlucidus, but way too cold for that, its all ice, not liquid at all as an Ac per would be. Sounding indicates our CIrrus clouds are between 35 and 40 KFT above sea level, temps up there between -40 (also -40 F) and -50 C. So, cold air is fairly close by, only a few miles away really.Hot dog. Bubba wanted to go out of the cool confines of the house, and I wanted to stay in to see what the little guy wanted to do, and why, when its 104 F outside. He chose a place on the boiling cement IN the sun, quite happy it seemed, until I brought him in after about TWENTY minutes! Almost as amazing as having a wild asparagus shoot up 40 feet in your backyard for no reason except maybe over-watering.Monster trying to grab something.Sunset (last evening’s).
The weather ahead
Wish it could tell you there was some rain ahead, maybe tomorrow, but…I’d be lying again as I do from time to time. Nothing in sight.
BTT you read this, rain oughta be falling or near by as the remnants of ‘Manda hurricane dribble into Arizona today. Looks like there’s just enough rain upstream right now (4 AM) to produce, hold your breath, a MEASURABLE amount here in Catalina! Likely will be just a few hundredths, though, as much as two tenths is about the top potential from this. At this point, anything measurable is a fabulous rain!
Mods have been oscillating on whether it would rain here for many days, but last night’s run ended pleasantly with a “correct” forecast of measurable rain. See green pixelation over Catalina below:
Valid for 11 AM AST today. Heart of rainband over us then, mod says. From IPS MeteoStar.
Your Catalina cloud day
(Also, another great cloud movie from the U of AZ here....)
5:15 AM. Cirrus, leaning toward “spissatus”, heavy dense patchy Cirrus.7:42 AM. Cirrus fibratus/uncinus. “Cirrus” will do it.
4:35 PM. What would a day be like without Altostratus? Here, “translucidus” because the sun’s position is visible. When the sun can’t be seen, its “opacus”, like a lot of science can be.
5:27 PM. Walkin’ doggie and this seemed like a nice shot of the rustic neighborhood streets, the Catalinas, and up top, some glaciating Altocumulus, castellanus on the right side; hasn’t gone through the ice forming stage yet, or the ice hasn’t fallen out that’s in it.
7:18 PM, Crepuscular rays show up as the sun sets due to smoke and haze under the clouds. The clouds? A mix of flakes of Altocumulus and Altostratus (the solid blob), some Cirrus on top of it all.
The weather way ahead…
Valid for June 12, 5 PM AST. Not a lot showing up here for mid-June weather, so won’t say anything about that. I suspect it will be warm, though.
The tropical fetch coming to Catalina (shown here yesterday) is from the remains of now strong hurricane Amanda, unusually strong for May for that matter, a month in which tropical storms in the Mexican Pacific are pretty rare, let alone have a Category 4 hurricane down there. Has sustained winds of 140 mph now, BTW.
When pointing out the tropical finches yesterday, was not aware that the low down there was, in fact, a hurricane. (Maybe I shouldn’t point things like that out, causing the one reader to lose confidence…. Too late now.) Check out this loop from the U of WA for the “pinhole” signature of strong hurricanes. Really happy to report that rain is on the way as May closes out (29th-31st are best chances for rain here).
Reprising yesterday’s cloud day…
1) Your day began with sprinkles from a cloud deck based at around 12, 000 feet above ground level (remember, too, that you can skip the “added value”, incremental approach below by just going to your great U of AZ time lapse movie. I thought it was really very pretty for yesterday):
5:32 AM. RW– (very light rainshowers) were falling from what could be called a Altocumulus opacus deck with scattered taller turrets embedded in it, ones that produced the sprinkles.
2) clearing from the north:
6:24 AM. The shallow nature of most of the Ac deck is apparent as the backedge moves toward Catalina.
3) once the clearing arrived, small Cumulus began developing on the Cat Mountains and “?”:
9:36 AM. I have no idea. Move along now to the next photo.
4) nice small Cumulus all around, sometimes filling in to make it seem like a Seattle day in spring, with patches of Cirrus on top:
10:16 AM. Cumulus humilis and fractus (those shreds) and that beautiful Cirrus seemingly spreading its icy arms out (spreading likely due to perspective).
5) Was there artwork in the sky? You bet. A niche developed here I immodestly remind you, is that of cloud bottom photography, something I enjoy, and I think you do, too. Below is one of the best ones of the day from the Cloud Bottoms Collection:
10:16 AM. Bottom of Cumulus humilis, maybe mediocris even, that was over ME. You look up, wondering, how deep is it? Will it form ice and rain on ME? Maybe graupel will fall out….since those are the first particles out the bottom of a growing Cumulus that is transitioning to a Cumulonimbus… So much to think about when a bottom is over you. Yours for $1,800, if you call now.
6) Late morning fill in:
11:23 AM. Cumulus and Stratocumulus dominated the sky for a time; looked threatening, but no frizzy ice seen around the edges. No ice; no precip or virga. Pretty, though, with those shadows and sun breaks on the Cat Mountains
7) Smoky sunset (not a western singer, though it would be a good name for one):
7:06 PM. Drifted down from the north. Likely hours old, judging by the striations in it (not well mixed out and homogeneous as would be smoke that’s days old). Could not find source in satellite imagery right off. I see that some of that layer is still visible to the SW this morning.
The End.
5)
6) Wildfire smoke drifts down in a thin layer from the N to spoil our sunset. Note the reddish orange sun, a good sign of smoke and smog particles, tiny ones (typically, if you really want to know, that are 0.01 to 0.1 microns in size) that eviscerate the shorter wavelengths of sunlight so that only the reddish ones get through.
Like you, my heart started pounding when that bank of thick clouds on the horizon got close enough to see that there was a rainshaft to the ground with a minor Cumulonimbus on top of it (ignoring the fact that you could’ve been hanging out by the radar all day).
6:47 PM. Cumulonimbus with rainshaft to the ground slowly approached near sunset yesterday. Big dust plume also visible to the right of the shaft a little later.
Today, the heart of the cold air and best moisture are over us and TODAY we will get those local icing-out Cu and small Cbs with sprinkles here and there. Measurable? Not so sure. Will be lucky. LTG in the area likely today, too.
If you’re a low temperature anomaly centric person at this time of the year (in texting, “LTACP”, or just “LTAC” for short), you will likely enjoy today’s 10 degrees or so below normal afternoon maximum, chillier even with outflows from virga and the scattered light showers around.
More later, photos, too… Behind on animal chores now.
Yesterday’s clouds
I thought it was a pretty nice day for you, though a little disappointing due to the late arrival of the minor rain threat mentioned above. You had quite an array of clouds to discuss in your cloud diary, which was good.
Below, I reprise them for you:
6:30 AM. Altostratus, the State Cloud of Arizona I think; Altostratus. We see a lot Cumulus, of course, but sporadically in the winter following a storm or trough like today, and in our summer rain season, but Altostratus we see year round.
8:49 AM. Mostly Cirrus uncinus (hooked, or tufted at the top).10:03 AM. Accas: Altocumulus castellanus. According to my cloud chart, it could rain with 6 to 196 hours after you see these clouds.
Sure, there was a little mischievous wind in the early afternoon, BUT, as a day in late May in Catalina/Sutherland Heights zone of Arizona, wherein the temperature is less than 100 F, well, it was pretty darn great. Another one is on tap today just like yesterday today, too. Feeling sad about the early, northerly ejections of “snowbirds” who thought because of the warm winter, May would be an inferno here and are missing some splendid weather. Doesn’t work that way. You just don’t know.
Lot of interesting clouds yesterday, too, real cold ones. Those Cumulus that formed in the late morning and afternoon started producing ice almost immediately. Wonder if you caught the first ones over there beyond the Charouleau Gap around 11 AM? They did not look as high-based as they were, thus, as cold overall, dad-gum, those cloud bottoms were running around -10 C (14 F)!
How high off the Catalina ground were they? Oh, about 13,000 feet, or about 16,000 feet above sea level (about 550 millibars). I woulda guessed, as you would have, about 8,000 feet off the ground when I first saw them forming (and not looking at the temperature and dewpoints, from which you can make a pretty good calculation of the cloud base height). From the Cowboys at the U of Wyoming, this sounding for TUS yesterday afternoon:
The Tucson balloon sounding for yesterday afternoon, launched around 3:30 PM, ascends at about 1,000 feet a minute.
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Weather Hints for Every Day Use by “Art”: You can calculate the height of a Cumulus cloud base by taking the difference between the temperature and the dewpoint, dividing it by 5, square that number, add the number you started with, and subtract the square root of 2.
DId I get the number you started with?
(Actually, stop at “dividing by 5”, multiply that number by 1000, and you’ll come out just about right. Yesterday, 85 F temp, 20 F dewpoint, leads to 65 F difference, divide by 5, you get 13, and times a thousand is an estimated CUMULUS cloud base of about 13,000 feet above you, not too bad).
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Continuing….. Since bases were so cold, tops were exceptionally cold, too, for shallow Cumulus and started producing ice when they were only about 1,000 to 3,000 feet thick, with cloud top temperatures of -15 C to -20 C (about 4 F to -4 F). Some of the highest tops, all east of us, and mostly on the east side of the Catalina Mountains, were likely as cold as -30 C (-22 F).
You can see yesterday’s small Cu spewing ice in the great U of AZ time lapse movie here. Only plays for one day, though.
You may also have noted in your cloud diary the bifurcation in the Cumulus array of yesterday. Almost no Cumulus west of Catalina, and plenty in the east half of the sky, appearing to be largest in the distance in the east. We were literally on the edge of the moist plume from the south that was hoped to end up been west, with us deeply embedded in it, and where measurable rain might have fallen here as it did east of us yesterday. Oh, well.
Today, with a low center passing over us tonight and a blob of Pacific Ocean air in it, and while that air is cold and pretty dry aloft, it will be a little more moist and so cloud bases today should be a little lower, and warmer, than yesterday’s. That means a little more water condensing in them than in yesterday’s clouds, and a greater chance of sprinkle here. Hoping for measurable, but its probably less than a 50-50 shot at that. Likely will be some thunder in the area of SE AZ, too. And, as always with high cloud bases, gusty winds that arise due to virga and rain falling through the dry air below cloud base. (Yesterday afternoon’s gales in the Sutherland Heights, momentary blasts of 40-50 mph, were NOT due to virga, but a rather to something I didn’t see coming, maybe a smallish low center–nothing really showed up on the maps.)
You will also see in the above loop that our low takes its time moving along, and will keep the skies interesting with Cumulus and weak Cumulonimbus clouds today and tomorrow, along with temperatures below seasonal norms for late May (aka, less than 100 F) ((Snowbirds left too soon; ice still melting off some areas of the Great Lakes!))
From the cloud vault; yesterday’s clouds
10:28 AM. Small Cu with lenticular type tops began forming in the lee of the Catalinas during a horseback ride with a friend, in case you didn’t think someone as cloud-centric as me could have a friend. Calm winds, then, too.11:08 AM. First ice! Can you spot it in the distance? Horse can’t believe that ice is forming already, and is rolling around in ecstasy, thinking about what it might mean for the afternoon.1:43 PM. Approaching low with air moving upward ahead of it, triggers a batch of Cirrus and Cirrocmulus lenticularis (really high lenticularis) upwind of Catalina and above some Cumulus fractus.3:18 PM. One of the more remarkable sights yesterday, were the small Cumulus clouds (humiilis or mediocris) that iced out. Look at ll the ice that formed in this small cloud, exiting on the left side, but dominates the whole cloud from this viewpoint. When you see this, it tells you how COLD those clouds are. First guess should be around -20 C at top when you see this much ice in a cloud this SMALL. Clouds having warmer bottoms, can have warmer tops that look this icy because ice forms in clouds at higher temperatures when the drops in them are larger (see Rangno and Hobbs 1994, Quart. J. Roy, Met, Soc.) Oh, yeah, baby, have some pubs!
6:58 PM. Iced out Cu/weak Cumulonimbus beyond the Gap, the Charouleau one, end the day. Shoot, a slight change in trajectory from the south, and they woulda been here.7:00 PM. Meanwhile, all quiet to the NW, no Cu whatsoever demonstrating the moisture edge we were on.
The weather ahead and WAY ahead
Now what I think is really interesting, which is almost everything to do with weather, is that the models are suggesting a tropical injection again at the end of MAY into early June, with a chance of a decent rain again. As you can see in the plot below from the NOAA spaghetti factory, a trough to the west of us and over California is a virtual certainty now at the end of May. That means the air above us will be, while quite warm, originating from the deep Tropics with the likelihood of clouds and precip coming up from there. Nice. Will keep me posted on these developments, in case no one else is reading this far.
First, pretty nice sunset yesterday evening, which is redundant because sunset always occurs in the evening.
7:18 PM. Altostratus with slight amounts of virga, underlit in the evening sunset. Haha, “evening sunset.”
7:19 AM. Liked the way was splayed over a house in the foreground. Sort of perty.
7:42 AM. The thicker Cirrus clouds are Cirrus spissatus, or “Cis spis” for short, though not in polite company. Should be the State Cloud of Arizona, we see so much of it, those white or gray patches of ice cloud. Kind of fed up with just “Cirrus-ee” skies these days.
7:43 AM. Looking north-northwest from Catalina toward Mt. Humphries, a delicate blend of Cirrus uncinus fibers (upper half of photo) with thicker Cirrus spissatus in the distance (thicker appearance not due to perspective).
OK, enough great information on clouds and things we can see from Catalina/Sutherland Heights, now for the rain ahead….
Rainshowers, some thunderstorms wrap around this low that drifts from over San Diego to over Puerto Peñasco, Mexico (aka, Rocky Point) by Saturday. Here the Canadian version of what the weather configurations will be this coming Saturday morning:
Valid at 5 AM AST, Saturday
As you can see, a little bit of tropical air gets whirled into this low from someplace down Mexico way, and, viola, showers and a couple of thunderstorms erupt. This could happen anytime between Thursday night and Sunday morning, maybe even a couple of days of scattered showers.
Rain here in Catalina? I think so. Likely range, not a lot, but from a low end of just 0.05 inches, to as much as a quarter of an inch by Sunday morning (10% chance of less; only 10% chance of more, as a first take on this). Gorgeous, dramatic skies are guaranteed, and likely some strong winds here and there emanating those high-based thunderstorms we can get this time of year.
BTW, not reporting on the US model forecast since it shows the low next weekend passing a little farther to the north, i. e., doesn’t take as favorable a track for rain here as the Enviro Can model shown above.
The weather way ahead
After the little “lowboy” goes by next weekend (producing some great, badly needed rains in NM and TX), the Arizona oven is turned on. Look for a string of 100+ days beginning in about a week.
Coming to weather theaters next fall and winter, “The Ninja (?) Nino.” Looks warmer and warmer down there in those key “Classic” and “The New Nino” equatorial ocean zones off South America to Hawaii. CPC’s (Climate Prediction Center) is getting pretty worked up about it, too. Check it out below and here:
Sea surface temperature anomalies from NOAA, valid for May 19, 2014. OK, here we go!CPC
Of course, as we know here, the effect on the summer rainfall season is not really well documented. But things can wetten up in late summer and fall due to tropical storms that drift farther north toward us, remaining a bit stronger because the ocean temperatures that maintain them are a bit warmer. This enhances the chance of a wet spell or two then. Mainly, with a good Nino, the chances of a wet winter go up a lot, particular the mid and later parts.
In the meantime, let us dream about September and October 1983, as the Great El Nino of 1982-83 was fading, but still was associated with colossal rains in Arizona those two months. In case you forgot, this recap about those days and TS Octave. During that water year of that Great Nino, October 1982 through the first couple of days of October 1983, just a year and a couple of days, Catalina recorded a Seattle-like 32 inches of rain!
From your Pima County ALERT gauges, these 24 h totals ending at 3 AM this morning (covers the whole storm):
Gauge 24 Name Location ID# minutes hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.04 Golder Ranch Horseshoe Bend Road in Saddlebrooke 1020 0.20 Oracle Ranger Stati approximately 0.5 mile southwest of Oracle 1040 0.08 Dodge Tank Edwin Road 1.3 miles east of Lago Del Oro Parkway 1050 0.20 Cherry Spring approximately 1.5 miles west of Charouleau Gap 1060 0.55 Pig Spring approximately 1.1 miles northeast of Charouleau Gap 1070 0.08 Cargodera Canyon northeast corner of Catalina State Park 1080 0.08 CDO @ Rancho Solano Cañada Del Oro Wash northeast of Saddlebrooke 1100 0.04 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Road
Santa Catalina Mountains 1030 0.75 Oracle Ridge Oracle Ridge, approximately 1.5 miles north of Rice Peak 1090 0.00 Mt. Lemmon Mount Lemmon 1110 0.75 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 miles south of Coronado Camp 1130 0.24 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.83 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.12 White Tail Catalina Highway 0.8 miles west of Palisade Ranger Station 2280 0.20 Green Mountain Green Mountain 2290 0.24 Marshall Gulch Sabino Creek 0.6 miles south southeast of Marshall Gulch
The absence of precip at Mt. Lemmon is not because the storm went around it, but rather because it fell as snow.
Here in the Heights, 0.08 inches fell between 1 PM and 3 PM. Clouds accompanied the rain.
But what kind? That’s why I am here for you. See way below.
First, some techno-babble. Rain was an on and off event for Catalina and environs in the models run after run. A forecaster friend sent many e-mails that went from “looks good for rain” here, and just about as many that said, “doesn’t look good for rain.” In fact, the (WRF-GFS) model run for just 12 h before it rained, had no rain here, but just a bit to the north. What happened?
Extra sag.
Here’s the amount of trough “sag” (“amplitude”, as we would say) over Arizona predicted just 14 h before it started raining in Catalina yesterday afternoon:
12 forecast valid for 11 AM yesterday morning. Note that the wind maximum is NORTH of Catalina, and over central AZ.
Areas of rain forecast to fall in the 6 h ending at 11 AM AST yesterday morning. Rain just a tad north of Catalina.A computer analysis of the actual winds at 5 PM AST yesterday showing that the trough had more amplitude (sag, droop, etc.) as it crossed Arizona yesterday than was forecast just a day or so in advance. That meant we in Catalina were more embedded in the deeper, and colder clouds with this trough. The jet stream circumcribes those clouds during the cool season here in AZ and most of the SW US. See rain totals at top of blog.
In case you think I am lying again, just because I am a meteorologist and say a lot of wrong things, below is the REAL map for last evening with wind data from rawinsonde balloons on it.
From the Huskies, this 500 mb map over satellite imagery. Strongest winds in our trough run from San Diego, Tuscon, to El Paso, with the tightest spacing of contours and strongest winds at this level in extreme northern Mexico
I hope you’re happy now.
Here’s what the temperature did as the windshift and rain began, in case you missed it:
Yesterday’s temperature trace for Sutherland Heights.
Yesterday’s clouds
The sequence: cloudy, sunny “sucker hole” (one of Biblical proportions), cloudy, raining, sunny, dusty.
6:06 AM. Altostratus and Cirrus combine to produce a gray start to the day.9:44 AM. Lower level moisture layer produces an Altocumulus lenticularis just beyond Pusch Ridge. Seems sky will cloud up real good at this point.Also at 9:44 AM. Looks real bad off to the N, too, in dense Altostratus and lower Sc or Ac.
10:57 AM. Sucker hole! Its real sunny, warming up. You’re thinking as you ride your horse as I was, “What a bad weatherman we have! Said would be windy, cold, and might rain, and yet here is the sun and warmth. What a bad weatherman we have!” (Weatherman is laughing in the background.)11:44 AM. Sucker hole starts to fill in… Haha! “Dreamer” is the horse there.12:10 PM Sucker hole filling in more and more! You’re starting to feel real bad that you made fun of your weatherman, but he’s still laughing at you.
1:17 PM. Rain showing up to west-southwest, upstream. Wind shift hits and ten degree cool off begins. You’re glad you finished your horseback ride none too soon.3:54 PM. A remarkable thing is happening. While there’s plenty of dust in the air. it is also still raining slightly, almost from drizzle-sized drops. Eyeballing the cloud depth at the backside of the rainband clouds from which the drops MAY have fallen from, your CM opined that these drops originated with melted aggregates of needle or sheath ice crystals that, as single crystals before aggregating, were in high concentrations (10s to 100s per liter) in those clouds, implying that a strong ice multiplication phenomenon was at work inside them. Was really a weird scene to have so much SUN and drops falling from clear sky overhead. I would be very proud of you if you noticed this few-minute event at the end of our little rain.
Rawinsonde balloon temperature and dewpoint profile near the time that it rained in clear air from the backside of our rainband. As you can see, cloud tops were around -10 C or a little cooler, pretty warm for raining clouds here. The main part of the rainband likely had somewhat cooler cloud tops. Thought you like to know. This sounding supports the idea that an ice multiplication process was at work, at least on the back shelf of these clouds that rained. I wanted to confirm prior ground speculations with more speculations from the sounding at rain time, though it was launched around 3:30 PM AST way over there by Davis Monthan Airbase. Wondering now if I will finish this blog today….4:34 PM. Shelf of rainband exits the Catalinas. Nice lighting, though.6:32 PM. While the rain may have washed a lot of dust out of the air, more dust invaded the area as soon as the rain ended.
Its not a breakfast at a restaurant chain, but a sharp cold front passage later this morning, say between 10 AM and Noon. Should be pretty interesting. Temperature will drop about 10 F in an hour. Expecting/hoping, too, for a little measurable rain with this “FROPA” (frontal passage in weatherspeak). The brisk winds, as they always do, have activated a lot of the nighttime wind detector lights in the neighborhood.
The usual post-frontal clearing in the afternoon and a pretty cool day, maybe 20 F cooler than yesterday afternoon which got to 88 F here in the Heights, the Sutherland ones, that is. Of course, our media weather stars are all over this weather situation, so nothing much to be added here.
Still have plenty of higher ice clouds overhead right now at daybreak, but look for an invasion of Cumulus and Stratocumulus within the couple of hours after daybreak. They should appear first on the Lemmon, topping it, then fill in after that as the cold slam gets closer.
Yesterday’s clouds
The full complement of expected clouds was not really observed yesterday. Missing in action for the most part locally were Altocumulus lenticulars downind of Ms. Lemmon. Cirrocumulus clouds were also pretty much a no show. You can see some of those high lenticular formations that did occur WAY downwind of Ms. Lemmon and the Catalinas if you view the U of AZ Weather Department time lapse movie for yesterday between 11 AM and 1 PM, then another pile of Ac len just at sunset (7:15 PM) in their movie.
Below, what we did see, various varieties of Cirrus, and eventually those thickening to Altostratus ice clouds. And a hole was out there that allowed a brief colorized sunset rather than a gray one.
9:20 AM. Main feature is Cirrus spissatus, with Cirrus fibratus (lines at upper right) and some uncinus (center left) also present.1:13 PM. Looking at incoming Cirrus to the WSW… More Cirrus spissatus (patches) in the distance with some hooked Cirrus (uncinus) upper center.1:14 PM. Looking N at the traces of Altocumulus lenticularis clouds (e.g., sliver cloud above road in distance), possible Cirrocumulus top center of photo.6:21 PM. By this time, the leaden look of Altostratus pretty much dominated the sky; dosen’t look good for sunset color at this point.7:03 PM. Sunset bloom began as bottom of Altostratus got lit up. Note how similar the cloud bottoms are in this photo compared to the one just above.7:06 PM. Heavy line of Altostratus with a higher overcast of CIrrostratus adds interest to the fading sunset.
