Cloud-maven – Page 66 – About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno

Smoke attack

It was hard to see all the smoke around yesterday morning after the two previous stunning days with high visibility. I was thinking I had never seen so much smoke in Catalina as I saw yesterday morning. Here is some photos of that awful event:

7:56 AM. Heavy dark smoke layer evident to SW. Some Stratus clouds also were present.

8:40 AM. Normally, in my experience here, such smoke is husbanded to that region south of Pusch Ridge. But no, not yesterday, its HERE! What an awful view this was!

8:45 AM. In this photo not taken while driving, you can see that there are TWO plumes the lower one drifting south from the area of the Golder Ranch-Sutherland Wash development of expensive custom homes that might have been burning wood for heat, while aloft is another plume. I could not tell where that came from, even in this time lapse from the U of AZ. Note how the Stratus clouds in the morning change direction in movement. — 8:45 AM. In this photo not taken while driving¹, you can see that there are TWO plumes the lower one drifting south from the area of the Golder Ranch-Sutherland Wash development of expensive custom homes, some of which might have been burning wood for heat, or something else woody, while aloft is a second, separate plume. I could not tell where the higher one came from, even in this time lapse from the U of AZ. Note how in the movie the Stratus clouds in the morning change direction in movement. The movement at first is from the west-northwest (left to right), and those clouds contained the higher smog layer. So, could it have been from PHX??? ———– ¹Smokey the Bear reminds drivers that only you can prevent smoky, well, a lot of it anyway.

In the afternoon, the smog was gone, mixed through a greater depth, the layering destroyed by the convection, those rising currents and compensating downward ones, that cream any morning layering. The dilution effect, and it also could have been that the aerosol load (smog) decreased with time, made things look much more clear. To this eye, there was still a lot of smog present, just diluted in the space between the ground and the bases of these small Cumulus clouds shown below. Still, there were so many pretty scenes on this horseback ride with a friend that I took more than 100 photos! Some water was present in some of the little washes, always nice to encounter, and some vividly green spots of of emerging growth (shown last).

The final point worth mentioning for pedantic reasons, is that yesterday afternoon’s TUS sounding indicated the same cloud top temperatures as the day before, about -12 to -13 C. Yet, there was no ice dropping out of those clouds. The day before, with the SAME cloud top temperature, ice and virga were widespread.

What’s up with that?

Ah, the complexities of ice formation in clouds!

When clouds are small and have a lot of droplets per liter in them, likely hundreds of thousands yesterday, given all the smog around, the drops end up being especially small because so many form on some of the smog particles (called “cloud condensation nuclei”).

In repeated flights at the University of Washington, we found that the resistance to form ice is dependent on not just on temperature, once thought to be the sole controller of ice formation, but droplet sizes in clouds as well. Small droplets sizes in clouds meant they were less likely to form ice, given the SAME cloud top temperature. Altocumulus lenticularis clouds are the poster child for ice formation resistance in clouds with their tiny drops, often having to be colder than -30 C before ice forms. On the other hand, clouds in the pristine Arctic around Barrow in the summer time, over the oceans away from continents, and in deep, warm based clouds even polluted ones, form ice at temperatures higher than -10 C when the drops in the clouds are large and have reached precipitation sizes (more than 100 microns in diameter to millimeter sizes).

So, it seems likely that yesterday, our shallower, pollutted clouds had smaller droplets in them than those deeper, less polluted clouds of the prior day in which we saw so much ice form in the later afternoon with about the same cloud top temperatures as yesterday. It is also the case, that when clouds are in large patches as they were the day before, that ice formation has more time to take place, and that, too, may be a factor.

Complicated enough? Yep.

2:18 PM. In the Catalina Mountains on the way to Deer Camp trail. Cumulus humilis dot skies. No ice evident. — 2:52 PM. In the Catalina Mountains on the back from the Deer Camp trail. Cumulus humilis dot skies. No ice evident.

2:18 PM. Cumulus humilis sitting around over Sutherland Heights, and the Oro Valley

The weather ahead

After another round of cold, this one dry cold just ahead for us, the heat is on by early March, and along with that heat in most of the West in early March, likely record cold in portions of the East. Check this 500 mb map out for the afternoon of March 2nd, produced by last night’s WRF-GFS model run at 5 PM AST, rendered by IPS MeteoStar:

Look at the size of that cold trough and low center! Huge!

That isn’t the only weather news ahead, cold in the East, warm in the West in March. Our upcoming cold shock that hits on Sunday, is caused by an unusually powerful upper trough that dips down into Texas after it blows by us, then roars northeastward across the South on Monday and Tuesday. Expect to read about godawful tornadoes in the South on Monday and/or Tuesday.

The End.

Snow and golf; a brief tirade, and yesterday’s clouds and why

I smiled seeing the groundskeepers scurrying about, sweeping and scraping snow off the courses and environs at the Dove Mountain golf tournament yesterday. I was smiling because the golf culture here is so different from that in Seattle, Washington, much more “pampering” here. Due to frequent inclement weather in Seattle, we have to toughen our skins against weather if we want to play golf. Rain? Snow? No problem.

In Seattle, golf season begins on March 1st. That’s because in March in Seattle, its only raining (or occasionally snowing) on every other day by then, not every day, as earlier in the winter.

So we’re going golfing on March 1st, dammitall, no matter what!

So shop keepers like this one below on Aurora Avenue in the north end of Seattle, knowing that Seattle golf culture, exult with big signs like this one when March 1st arrives!

The golf weather culture in Seattle, Washington as represented by this sign. — The golf weather culture in Seattle, Washington, as represented by this sign. Photo by the writer, March 1st, 1990.

Inaccuracy in media re Catalina snowfall or maybe it wasn’t: a tirade

I was thinking that maybe a tirade would be a nice change of pace for you before some cloud discussions.

First, since I heard a weather presenter report that “2 inches” of snow fell in Catalina, a visual correction to that report. There was FOUR inches on the ground after settling/melting during the day and night of the 20-21st. If there is FOUR inches the following morning, it HAD to have snowed quite a bit MORE than FOUR inches! (The total depth of snow that fell was 5.5 inches here on Wilds Road).

Here is the proof, 4 inches of depth as measured by a raingauge dip stick, one tenth inch markers are 1 inch in length–I didn’t have a regular ruler. Some of the labels indicating light amounts of rain have worn off while the stick was being used in Seattle for 32 years, so you’ll have to count down from the 1.00, 90, 80 hundredths labels, ones clearly visible. For added proof I have added a second photo, and if you call now, you’ll get a third photo free plus for $75 for handling and shipping…

8:41 AM, February 21st. A raingauge measuring stick protrudes from a FOUR-inch depth of snow on a hitching post (where some snow could have even slipped off, or blew off!) — 7:02 AM, February 21st. A raingauge measuring stick protrudes from a FOUR-inch depth of snow on a hitching post (where some snow could have even slipped off, or blew off!)

7:04 AM. A slightly higher depth on a second hitching post--oh, yeah, leading the big western life here in Arizony. — 7:04 AM. A slightly higher depth on a second hitching post–oh, yeah, leading the big western life here in Arizony with a horse and hitching posts.

I felt sad, though, remembering the words of humorist Dave Barry, speaking to the National Press Club back in ’91 I think it was, when he diverged from humor into a serious note, admonishing his Press Club Audience: “Why can’t we get it right?¹”

Maybe in our case of the missing snow, it was because the person that called in the report was not a Cloud Maven Junior, and did not know how to measure snow. Maybe less actually fell where that person was (unlikely). Let us not forget that the snow on a flat board in Sutherland Heights, above Catalina proper, measured at nearly the same time as this, was SIX inches!

Yesterday’s clouds, and those snow-covered mountains

While it was sad to see so much snow disappear so fast, it was, overall, another gorgeous day in a long nearly continuous series of ones since the beginning of time here in Arizona, except maybe for those days of upheavals and dinosaurs and then when it was underwater, a remnant of the latter epoch as shown here in this fossil of a hydrosaurus, a precursor to grain eating critters like the Perissodactylas we have today…(horseys and such). As you can see, the teeth here were for eating something like mueslix, not for ripping flesh. I can’t believe all the information I am providing you today!

Possible hydrosaurus fossil encountered on a hike in Catalina State Park. Finding was reported to park rangers. — Possible hydrosaurus fossil encountered on a hike in Catalina State Park (still checking on what it is). Finding was reported to park rangers.

Here are some shots with some notes on them or in the captions. First those MOUNTAINS!

8:21 AM, February 20th, looking east from Sutherland Heights, which had SIX INCHES of snow on the ground at this time. Stratocumulus clouds top Samaniego Ridge.

9:13 AM. THe snowy Tortolita Mountains with some Altocumulus perlucidus above. — 9:13 AM. The snowy Tortolita Mountains with some Altocumulus perlucidus above.

2:25 PM. With most of the snow already gone around Catalina, the majestic Catalina Mountains remind us of our great snowstorm and why we live here. — 2:25 PM. With most of the snow already gone around Catalina, the majestic Catalina Mountains remind us of our great February 20th snowstorm and why we live here.

2:26 PM. While it was serene-looking over the Catalinas, to the southwest the sky was filling in with Cumulus and slightly higher Stratocumulus clouds. Why don't you see virga even though we know they are at below freezing temperatures? In unison: NO ICE! — 2:26 PM. While it was serene-looking over the Catalinas, to the southwest the sky was filling in with Cumulus and slightly higher Stratocumulus clouds. Why don’t you see virga even though we know they are at below freezing temperatures? In unison: “NO ICE!” (Tops too warm and cloud droplets likely on the small side.) This was to change in the next couple of hours.

3:24 PM. But first, another look at the Catalinas from Shroeder Ave because I think its worth it before continuing. — 3:24 PM. But first, another look at the Catalinas from Shroeder Ave in Catalina because I think its worth it before continuing. Golder Ranch Drive is on the far left.

5:25 PM. Clearly there has been a change in the temperatures at the tops of these clouds, likely now colder than -10 C. A trough of colder air was approaching aloft, and that likely lifted and cooled cloud tops. The cloud layer was due mostly to the spreading out of Cumulus tops (Stratocumulus cumulogenitus). The TUS sounding indicated cloud tops were around -12 C, capped by a very strong stable layer. — 5:25 PM. Clearly there has been a change in the temperatures at the tops of these clouds, likely now colder than -10 C. A trough of colder air was approaching aloft, and that likely lifted and cooled cloud tops. The cloud layer was due mostly to the spreading out of Cumulus tops (Stratocumulus cumulogenitus). The TUS sounding indicated cloud tops were about -13 C, capped by a very strong stable layer. There was a fall of sparse drops around this time, so some of it was getting to the ground.

The weather ahead

Cold then HOT. Hot when? Heat’s on already by March 1st for sure. Look at this “signal” in our trusty NOAA “ensembles of spaghetti” from last night:

: Valid for 5 PM AST, March 1st. You won’t see a signal stronger than this one for 8 days from now. Likely will reach into the 80s when this ridge of warm air is fully developed.

The End, at last. Anyone still there?

—————————

¹Deadlines have a way of getting in the way of “truth.”

An unforgettable snow day in Catalina, Arizona

Three separate bands of snow in one day? Unforgettable, if not unbelievable, for Catalina, Arizona, made more so because its late February occurrence. Here at the top of Wilds Road we received a total of 5.5 inches from those three bands, with a peak amount of 4 inches on the “ground” (actually it was measured on a hitching post) just as the third and final band ended at 9 PM last night. The totals with each band, measured just about the time the snow was ending¹:

Time of band Top of Wilds Road: Sutherland Heights (1 mi NE and 170 feet higher)

11:30 AM to 2:30 PM 2 inches 3 inches

4:30 to 6:00 PM 2.5 inches 2.7 inches (most fell in an hour and a half!)

8-9 PM 1 inch 2 inches (this just in), 6 inches on the ground there in sheltered locations)

Totals: 5.5 inches at the top of Wilds; 7.7 inches in Sutherland Heights. What a day, Mr. and Mrs. Catalina!

Water content in this snow here, 0.49 inches, so far. Waiting for melt down to get last few hundredths still frozen on the sides of the collector of the tipping bucket raingauge. Measured at Sutherland Heights: a fabulous 0.73 inches!

It’ll be gorgeous in the first few hours today after dawn, but with our late February sun, our great local scenes won’t last long. While more cold air is ahead, though with no precip in the few days, a HEAT WAVE has reared up in the models for the beginning of March, 8-10 days out!

Some photos for yesterday’s memorable snows² (plural here is even amazing), From the beginning…

7:37 AM. A blustery cool dawn, snow showers in progress on the Catalinas from relatively shallow Stratocumulus clouds. — 7:37 AM. A blustery, cool, and dramatic dawn scene, with snow showers in progress on the Catalinas from relatively shallow Stratocumulus clouds racing along them from the south.

9:39 AM. A very exciting moment here! A non-preciping line of heavy Stratocumulus gets cold enough on top to start preciping over Oro Valley. Here we go! How cold were those tops getting? You want to guess, “Oh, about -10 C or so.” The TUS sounding at 5 AM AST had tops in that range already.

11:37 AM. Just after the windshift and a 10 degree temperature drop from 44 F to 34 F, the snow begins to fall in Sutherland Heights.

: 6:11 PM. Wider angle view of that same scene after the second band dropped 2-3 more inches of snow in just over an hour. Getting pretty dark, camera or photog not doing the greatest job here.

5:59 PM. Can you imagine what this blue palo verde tree is thinking? — 5:59 PM. A blue palo verde tree bowing to snow.

5:57 PM. "Piling it higher and deeper", a common expression likely referring to snow. — 5:57 PM. “Piling it higher and deeper”, a common expression likely referring to snow and one that’s valid here.

5:22 PM. How'd it get like that shown in the prior photo? Like this, a shot in the middle of S+ ("heavy snow" in weather teletype parlance) — 5:22 PM. How it got there… This is a shot during the heavier, second snow band during its prime S+ burst. “S+”, is “heavy snow” in weather teletype parlance, an early form of “texting.”

Will be taking more photos of course, early today!

The situation aloft (500 millibars) as S+ snow band 2 hit:

cropped 500 — For 5 PM AST February 20th. The low center aloft is perfectly positioned for us as new precip bands are generated near its center as it sped eastward. Newer bands are heavier than older bands as a rule, and Band 2, was quite young with lightning in it. Band 3 is just forming, and it too, was mighty, though less extensive than Band 2.

Today’s clouds

Some Cu-Stratocu, patches of CIrrus and Altocumulus as a another lobe of cold air races SE from the Pac NW today. There’s a chance of snow flurries late tonight into tomorrow morning (can you imagine?) as the core of the trough goes by.

The End.

———————————————

¹Measuring snowfall and snow on the ground, is one of the biggest bugaboos we have in meteorology. If there is any wind at all, forget about getting an accurate total, too much blows over the collector can. So, the precip amount reported for this storm is going to be on the low side. And, as the snow piled up yesterday, it was also disappearing at the same time on the bottom due to melting. Finally, as it piles up, it sinks down due to weight. So, the depths reported above are conservative, since if all the snow landed on a below freezing metal plate, we would only be dealing with one of those problems, settling, as with snowpacks in the high mountains.

²Hardly any of which was forecast from this keyboard. Wish there was a font smaller than ” 1 point” and this is it, in case you’ve never seen it. You don’t want to rub it people’s faces that maybe you were a little asleep at the wheel; too preoccuppied with the amount of precip which you forecast was going to be MORE than the models were predicting, and which happened, not the phase (solid or liquid) of the precip. But then, what REALLY matters to the vegies out there? The amount, of course, well, OK I guess vegies like it if more if the water sits there in a form that melts and has a lot of time to soak in.

Harder rain falling now at 4:04 AM; you’re probably not up

I’m not missing any of this. Its too good. Supposed to rain off and off until the frontal blast about 10 AM -Noon, then clear up for awhile, then scattered showers develop from what will be icy looking Cumulus and small Cumulonimbus clouds, kind of the usual storm chronology we have here. This sequence shown in the U of AZ model run from last night is here, and its been well-predicted by the media weather folk as well. Don’t watch TEEVEE much, but I did catch some bits and pieces by George. It was pretty comprehensive, quite good really, and then I started to feel sad. Why am I doing this, blogging about weather myself when its already out there???????????????????????? Oh, well.

It will be interesting to see if there is more than a few flakes of snow as the front goes by, the rain becomes moderate to briefly heavy, and that’s when the precip will start to have ice in it, maybe turn to snow for awhile due to a diabatic effect where the snow level comes down due to big melting snowflakes dragging it down. An early morning frontal passage would have been better for the best snow accumulation, but, oh, well.

Still looks to be an appreciable amount here, both eyeballing the situation and in the U of AZ mod run from last evening. From this keyboard yesterday, the best estimate for this storm that just kind of popped out was 0.450 inches (the median between a lower limit of 0.20 and upper one of 0.70 inches). Since “we” last wrote, the U of AZ model has increased its precip for us, as though it was affected by something I said. The green “half inch” region has crept that bit closer to Catalina in this latest run below over where it was yesterday.

Accumulated precip for the 24 h ending at midnight tonight.

And we’ll need as much rain as we can squeeze out of this one as the follow up series of storms foretold so long ago in the mods have disappeared–shown during a time when our “truth viewer”, those NOAA spaghetti plots were down for a few days, or they might have tipped us off to be more “circumspect” about a run of storms by showing that they were not reliable predictions. No further rain is forecast for the two weeks after this now! Dang!

The intermittent rain that has been falling is WAY ahead of the front, over there by Yuma as I write at 4:41 AM.

IPS satellite-radar loop for the Southwest here.

Its developing in the moist flood of air that rushed in overnight at lower levels along with a huge icy shield overhead, no doubt a thick Altostratus with virga on top of Stratocu, maybe dumping some drops into the lower cloud deck. Need more of that.

——————Learning module———————–

The effect of rain drops falling into a lower layer of Stratocu?

If you dropped a cup of water on the top of the layer yourself, the amount coming out the bottom would be more than a cup. Those fast falling drops, about 5-10 meters per second, say for regular raindrops, collide with the itty bitty cloud droplets blowing sideways in the wind. The larger cloud droplets, say bigger than 20 microns in diameter, collide and stick to the fast-falling raindrop, adding to its size. We call this accretion. That bottom kilometer of storms where otherwise “harmless”, non-precipitating Stratocu is likely to be, is critical for appreciable snow and rainfall due to this process in mountainous regions. Almost always, the impression is that its the Stratocu that’s precipitating, but usually its not. So, when you see a raindrop fall, thank a Stratocu deck for making it that bit bigger, thought in some cases to increase precip by 50% due to the effect of accretion in the bottom kilometer (3300 feet).

Might look like this if you could step back to the south of the Catalinas today and draw a crummy cartoon of what was happening, but it was the best you could do at the time

From a 101 class I taught at the U of WA, with modifications to show I am in Catalina, AZ. Background: couldn’t get the real guy to teach that class that summer, and so I was enlisted to do the job at the last minute, thus lowering the accreditation rating of the University of Washington. You see, I have NO ADVANCED degree of any kind, and to have a lecturer without the big Ph. D. means you go DOWN! On the other hand, unlike most faculty at ANY university, I have been asked my opinion on something and was quoted about it in the Wall Street Journal in 2011! Oh, yeah, baby! Wanna spike a football right now! Credentialism; a bunch of hooey (sometimes).

————end of learning module and statement on credentialism aloong with a display of immaturity—————

Back to the storm…. After a couple of light and brief showers, we have amassed 0.01 inches! Only 0.44 inches to go to make a perfect prediction!

Yesterday’s clouds

Kind of a bust, really, and admitting that will make up for some exultations above. Sure, there were some Altocumulus with virga hanging down, but those virga trails needed to be about 20,000 feet longer to be anywhere near where I thought they would be. And then it cleared off almost completely during the afternoon! Oh, well. Pretty day, with lots of wind and mild temperatures. Here are a few shots:

6:55 AM. Altocumulus floccus virgae--has virga. These were up around 20,000 feet above sea level, or about 17,000 feet above ground level here in Catland. Top temperatures with all that ice falling out? About -26 C (-15 F). — 6:55 AM. Altocumulus floccus virgae–has virga. These were up around 20,000 feet above sea level, or about 17,000 feet above ground level here in Catland. Top temperatures with all that ice falling out? About -26 C (-15 F).

6:25 PM. A vast shield of Altostratus/Cirrus advances on Catalina. — 6:25 PM. After a clear afternoon, a vast shield of Altostratus/Cirrus advances on Catalina.

The End for now, anyway.

Yeah, yeah yeah: a good rain, wind, and cold coming; but what about those strange clouds last Saturday?

The storm

…and it will seem like one. Windy today, real windy tomorrow morning before the cold front goes by in the mid-morning. Clouds is already here, rain predicted to develop SE of us in Mexico during the day. A jet max at 500 mb is already to the south of us, and that means that the door is open for a moist flow from the Pacific ahead of the main storm today, before the main blast tomorrow. So, there’s a chance of sprinkles and light showers around our area even today from thick splotches of middle and high clouds and the virga that will fall out of them.

But tomorrow; that will fab. Bruising cold front, gusty puffs of wind to 40 mph or more here in Catalina, especially likely on the higher ground, before it hits, followed by our “usual” huge temperature drop of 15-20 degrees in 1-2 h around mid-day, lets say about 10 AM-noon tomorrow, Wednesday (U of AZ mod run from last night sez it passes between 8-9 am AST, FYI, sometimes its a little fast). There ought to be light to moderate rain, briefly even heavy rain as it passes, maybe with some ice in the bigger raindrops.

What exactly is moderate rain you ask?

0.10 to 0.30 inches per hour, water is running off stuff pretty good. Its pretty common in most of our frontal bands. Heavy rain, which I think we will see, is just more than 0.30 inches per hour; drops are bouncing off the pavement an inch or two in height, and there are a lot of them. Now, it may not LAST an hour, this is just what you would call it if that intensity is reached. As a respectable CMJ, you’ll want to keep these numbers in mind, in case your friends ask you about something like this, “You just said ‘moderate rain’, what izzat, anyway?”

What the chance of measurable rain in Catalina and environs between now and Thursday morning?

About 200-300 percent, maybe 1000 percent on top of Mt. Sara Lemmon or even on Samaniego Ridge with this Big Boy blaster tomorrow. (We’re breaking new forecast ground here….you won’t hear the NWS telling you that the chance of rain is 200 percent!) ((Tell your friends.))

Amounts of rain here in Catalinaland?

Mods have juiced things up a bit, but a friend reported that yesterday the WRF-GFS had “as much as 0.25 inches” here. Friends, I pooh-poohed that forecast yesterday because it was TOO DAMN LOW for what we have coming. Besides, we need more than that, and this storm will deliver.

From this weather bully pulpit, the minimum amount, surely to be exceeded here, is 0.20 inches, the top I think now is more like 0.70 inches, that is, its not likely to exceed that amount. The median amount, the one most likely, the average of these two extremes, is 0.45 inches, a really good, and very needed rain. Its great to be able to say things like this, make people happy, except maybe snowbirders. Look, too, for happy Catalina Mountains with a LOT of snow on them. Get cameras ready for extra nice shots Colorado-ee shots on Thursday!

Hah, just looked at the U of AZ mod for the first time, and it is predicting that Catalina is in the 0.25 to 0.50 amount category, and Mt Sara Lemmon gets 1.5 inches! Yay! This will be so great if it happens, for our water situation. You can see that output here.

Saturday’s violent clouds

Never seen anything like them, those strange, and to me, violent looking high clouds, seemingly with tiny rope vortices in them; I swear I could see rotation. Here are a couple of shots. They seemed to pop out of blue sky for a few minutes, then disappear, then pop out again downstream some (toward the east).

12:24 PM, Saturday, Feb. 16th. There is no name that I know of that fits these clouds.

12:38 PM. The one on the left just shot up in a minute or two; the one on the right MAY have a rope vortex in the middle.

I didn’t remember to check PIREPS until long after the event. But, got help from NOAA’s David Bright who sent me a list of ones for Saturday morning throughout the West. Only one was intriguing in that list; “urgent, mod-sev turb….FL 310” (moderate to severe turbulence, flight level 31000 feet). But when I plotted the coordinates of that (9 AM AST PIREP, it was just about over San Diego, CA, and it was at 16 Z. There was nothing reported near us at the time of these photos, taken between noon and 1 PM (19-20 Z). But could that turbulent air, as represented by these clouds at Cirrus level, have gotten here from San DIego?

Below is the back trajectories starting at 9 km and 10 km ASL (30,000 to 33000 feet above sea level). Seems to lend credibility that our strange clouds MIGHT be the associated with the same region of turbulence reported by that pilot.

6 h ack trajectory for air arriving north of Catalina at 30 Kft and 33 KFt on Saturday, Feb. 16th at 2 PM.

Adding more mystery is the truncated TUS sounding, also attached, and the wild wind shifts. Did they lose the balloon? Maybe the balloon couldn’t take it, gave up as it got close to the turbulent layer above 22 KFT. Note how wild the wind direction got above about 16 KFT, or about 550 millibars. Normally these plots extend to the top of the diagram, 100 mb, but not on the afternoon of the 16th. Hmmmmmm.

The Tucson sounding, launched around 3:30 to 4 PM AST for Saturday afternoon, Feb. 16th. It will be known, in Z, or CUT time as the sounding for 00Z, Feb. 17th.

BTW, I have done a lot of work here for you on this strange case.

Yesterday’s beautiful uncinus, and another great sunset

Yes, mare’s tails on display yesterday. They make hygrometers out of of horse tail hair… Did you know that? Yep, its true. Horse tail hair responds to changes in humidity really well. You wonder who and how that was discovered? “Wow, look at how fat and short my horse’s tail is! Must be really humid today! I think I will grab a hair and make some kind of humidity sensor out of it, one that has linkages that trace the humidity on this little drum that goes around. I’ve always wanted to make something out of my horse’s tail.” (That venerable instrument? The horse hair hygrometer. Used for decades.)

9:38 AM. Does it get prettier than this? I don't think so. — 9:38 AM. Does it get prettier than this? I don’t think so.

6:19 PM. Patch of Altocumulus undulatus (has ripples), center, along with patches of Cirrus and Altostratus. — 6:19 PM. Patch of Altocumulus undulatus (has ripples), center, along with patches of Cirrus spissatus (thick Cirrus) and maybe some lenticulars on the right. It was a complex scene!

The End.

Morning smog bank invades Catalina, smokes up clouds real good

I wonder if you noticed the blackish smog layer to the south and southwest of Catalina yesterday? Usually it stays down that way, flowing peacefully toward the northwest from Tucson across Marana and Avra Valley, an area where a close meteorologist friend and his wife just bought a house even though they knew this happens in winter and not one in Catalina where we normally escape this characteristic Tucson smog plume. They must like winter smog overhead, but then as the sun heats the ground, it comes down to you. Go figure.

Here is yesterday’s Tucson smog plume exiting Tucson:

8:47 AM. Smog plume exiting Tucson, moving left to right over Twin Peaks area. This was one of the densest, most awful ones I’ve seen from Catalina.

But then, in the later morning hours, a southerly wind brought that smog bank to our normally clear air oasis of Catalina, infecting the shallow Cu fractus clouds that formed as the sun heated the ground. This was a real disappointment since probably most of us were expecting the kind of pristine view of the Catalinas yesterday morning.

10:09 AM. Smoke-filled Cumulus fractus clouds form along the Catalinas as the air begins to warm. — 10:09 AM. Smoke-filled Cumulus fractus clouds. The smog looks white here instead of dark because of “forward scattering”; the white light of the sun is being scattered in the viewer’s direction by the smoke particles. (In the first photo, there was no forward scattering and so you can see the actual dark hydrocarbony smoke particles for what they are, dark and sooty.

Fortunately the smog was dispersed as the day wore on. As the layer in which it is contained gets deeper, and without more smog being added to it, the amount of smog, say, per cubic mile diminishes and pretty soon it gets so thin you can’t detect it with your eyes. Still, exactly the same amount might be in the column of air between you and the higher cloud bottoms. Here’s what it looked like in the later afternoon:

4:29 PM. That's better! Cumulus humilis dot skies. — 4:29 PM. That’s better! Cumulus humilis dot skies.

BTW, while its easy to see that the Cumulus fractus clouds in the second photo are very low, in the 3rd photo above it’s much harder to detect how high these small Cumulus are. The TUS sounding indicated that they topped out at 9,000 feet, or only about the same height as Ms. Mt. Lemmon! Top temperatures in these smoke-filled clouds were no colder than about -8 C (about 20 F), too warm for ice to form in them, especially when the cloud droplets are reduced in size by smog. The larger the cloud droplets, the higher the temperature at which ice begins to form in them, and so smog generally reduces the chance of rain in shallower clouds.

This is why oceanic clouds in pristine regions lacking smog, even shallow ones, rain or drizzle so easily. The cloud droplets are much larger in those clouds right from the get go than those in smoggy regions. So oceanic clouds can rain either because those larger cloud drops reach sizes where they can collide and stick together, forming larger drops that can fall out (“warm rain process”) or form ice at the highest temperatures known for ice formation, -4 to -5 C (23-25 F). Usually both processes are work in those ocean clouds that rain so efficiently. They’re pretty great, really, such little clouds that rain.

Vacation in Hawaii if you’d like to see some up close (though not downwind of the Kilauea volcano plume and in the lee of the Big Island of Hawaii since that volcanic plume can smoke up the clouds real bad there and they stop being so darn efficient as rain producers. Recall that the biggest drop in the world was measured in clouds in Hawaii (1 cm in diameter, Beard, private communication, received AFTER Peter Hobbs and me got the Guinness record for the biggest drop ever measured, 8.6 mm in diameter–got a lotta publicity around the world, too, calls came from everywhere!).

You see, Beard didn’t publish anything about HIS BIG DROP; we published ours in a refereed journal. “Neeny, neeny, neeny”, I think is what you conclude here. Immaturity: sometimes I think its not valued enough in life.

That’s what its like in academia; you publish or die! Die that slow death as an “Assistant Associate” professor of something, never reaching the exalted “Professor” status.

The “combo” ice seen yesterday morning

We had two forms of ice yesterday morning that you may have noticed, say, on your car if it was parked outside overnight. There were originally rain drops left from the storm that froze in place during the cold night (was 30 F here yesterday morning), and then the deposited ice from water vapor on top of the drops.

The deposition process, as we call it, leads to hoar frost ice crystals growing in time as the molecules of water vapor add to it during the night. This combo ice led to an unusual site on the car before the sun did away with it. Here are a couple of shots of this unusual sight:

9:57 AM. "Strange brew." — 9:57 AM. “Strange brew.”

The weather ahead

After the “sunny malaise” for 5-6 days, with Arizonans statewide out doing things, its back to the Bowl, the trough bowl. The period we’re in now might be called, “a sucker ridge”, a high pressure ridge that is. You might well think, “Well, that’s it for winter in Arizona!” after a few days of the “sunny malaise”, but you’d be WRONG. I can’t emphasize the word, “wrong” enough. The Bowl comes back with a vengeance, too, when it reforms here in the Southwest; there will be one storm and cold blast after another. If you’re a snowbird, you might start to cry, and wonder why you didn’t go to Costa Rica for the winter.

Well, I am looking forward to storms and seeing more scenes of white mountains deep in snow, and green vegetation shooting skyward. That’s the promise of the “Bowl” ahead, where storms collect, in the weeks ahead right into March.

Taking a few days off now, likely without pay, to replenish mind, get out and do things like the rest of Arizonans will. Will give you time to ruminate on all that’s been said here over the past year or so, correct and incorrect, mature and immature…

The End.

Stratiform clouds bring steady rain and snow; sixteen hundredths to Catalina

“Sixteen hundredths”, originally a song by a boy group of that day so long ago, The Crests, about a light rain that fell in May in southern California, an event that is quite rare and exciting at that time of the year there. But then practical and marketing considerations caused the song to be revised to one about candles of all things. How odd. I thought you might like to know some reliable history behind that venerable song, one that made us cry, it was so sweet, and think about, as boys, how much we liked girls when WE were sixteen or so.

Yesterday, while Mr. CMP (“cloud maven person”, but using acronym in trying to be as indirect as possible here) was making some fun of students mixing up units in their calculations of pressure at various heights in the atmosphere, he himself was mixing up cloud “units”, by informing his reader that cumuliform clouds, some dropping graupel, would be seen over Catalina yesterday, not stratiform, sky-covering Altocumulus, followed by great masses of Stratocumulus underneath it, combining later with gray, dank, Altostratus, a scene that finally evolved in the mid-day hours into Nimbostratus with light rain, sometimes with light snow mixed in! Briefly, too, it was ALL “surprise” snow!

The total, 0.16 inches, was also about sixteen times more than CMP thought would fall from that perceived marginal weather producer. (Note: the U of AZ local model’s 11 PM run the night before had it predicted perfectly! However, in some kind of bloated self-evaluation of skill levels, CMP did not consult that model until it was “too late.”) Today, I am quite confident, however, that I really don’t need to look at that model…

What is going on here? Fallibility, I calls it, human fallibility. Remember that old saying about pencils with erasers at the end? So simple and yet, profound.

Oh, well. All’s well that ends well, and the “well” ending was one of a nice little rain mixed with snow (will burn your CMJ tee if you refer to rain mixed with snow as “sleet”!) and beautiful snow down on the Catalinas, so pretty yesterday evening as the clouds lifted.

Today a fine day with small Cumulus clouds, very photogenic again as this kind of wintertime day is here. The mountains should be spectacular, too, due to the cold air that remains that will allow them to be white down low for a few hours this morning.

Pima County precip totals here.

Precip totals from the U of AZ rainlog.org network here and the national CoCoRahs org here for AZ totals. The measrements at rainlog will indicate that they are for yesterday, the 11th, while the CoCoRahs convention, to assign the rain to the date it was reported, will show the totals for our storm using today’s date, the 12th. You’ll have to wait until about 8-10 AM to get most of the loggers’ reports.

The most I saw in the Pima County gage network was 0.43 inches, an amazing amount, down in Avra Valley. Shocking, really.

BTW, the cloud regime that CMP foresaw for Catalinaland was just to the west of us, around Ajo, AZ, not that far away astronomically speaking. And at sunset yesterday, you could see those Cumulonimbus clouds on the horizon coming into view.

5:53 PM. The forecasted Cumulonimbus clouds begin to come into view. — 5:53 PM. The forecasted Cumulonimbus clouds for Catalina begin to come into view. I wish I could make this image bigger, maybe in 3-D so you could “feel” this cloud coming at you.

To cry-baby about it a bit more about a missed cloud forecast, this “visible” wavelength satellite image:

Some un-Cumulus scenes from yesterday:

10:30 AM. Altocumulus perlucidus undulatus and Stratocumulus begin overspreading the sky.

11:41 AM. Dark bases of Stratocumulus-Cumulus line up with the wind and head toward Catalina. Virga spews in the distance on the right. Above these clouds was an icy layer of Altostratus.

11:58 PM. Mounding tops of Stratocumulus-embedded Cumulus become infected with ice and spew forth virga. Now under this guy, there may well have been a couple of graupel. — 11:58 PM. Mounding tops of Stratocumulus or embedded Cumulus become infected with ice and spew forth virga. Now under this guy, there may well have been a couple of graupel. Above these clouds was an icy layer of Altostratus that helped impregnate the lower Stratocu and Cu with ice, kind of like seeding them.

1:17 PM. The lumpy and dark looking bases had disappeared in the virga and snow falling from the thickening Altostratus layer as it became, Nimbostratus. What you're looking at here is a classic example of snow melting into rain that appears to be the base of the cloud, but its really a transition zone that reveals the snow level. — 1:17 PM. The lumpy and dark looking bases had disappeared in the virga and snow falling from the thickening Altostratus layer as it became, Nimbostratus. What you’re looking at here is a classic example of snow melting into rain that appears to be the base of the cloud, but its really a transition zone that reveals the snow level.

3:14 PM. Snowing hard in Catalina for a few minutes. Here's what it looks like, coming down at you. Some aggregates of snowflakes were more than an inch across. — 3:14 PM. Snowing hard in Catalina for a few minutes. Here’s what it looks like, coming down at you. Some aggregates of snowflakes were more than an inch across.

5:42 PM. The result of our little storm on the Catalina Mountains, Samaniego Ridge.

The weather ahead into March

Gotta ride the storms, ones already predicted as of yesterday here over the latter half of this month. Never good to “yo-yo” on a forecast, as forecasters will tell you.

However, not getting help again in this longer range musing from the NOAA ensembles of spaghetti; site is still down, so riding bareback here so-to-speak, using a western idiom (or is it “idiot”?) In sum, Arizona to end up with above normal precip when whole state considered. This due to being in the bowl, the trough bowl, though breaks in storms, and nice weather, sometimes for several days at a time, will try to fool you into thinking you’re not.

Going farther out on a limb, twig, really, looks like the active storminess will continue well into March. We seem now to have a wet pattern going, though in a desert, its not THAT wet compared to Washington State or elsewhere. Stand by for occasional updates. Am excited for wildflowers now; there may be some!

The End.

The Arizona 500

Its not about car racing…. though that might be more exciting than what I am going to write about. This is a discussion about 500 millibar maps and what you can get out of them.

Here’s this morning’s 5 AM AST 500 millibar pressure map below. Knowing that sea level pressure averages 1013.6 millibars, then 500 millibars, around 18,000 feet or so, is about halfway through, in pressure anyway, ALL the air above us that we have on this planet. Thins out, of course, as you go higher; 10 millibars, for example, is around 120, 000 feet above sea level. You don’t want to be there. Thought I would check around for that height of the 10 millibar level, and here’s what I came across

At this link on the web, however, it is calculated that the 10 millibar level is reached at “5.48 miles” above sea level, and at 4 miles above the sea level, about 21,000 feet, the pressure is but “13.44 mb”! I started laughing because you’d need a space suit to be at the top of our Mt. Lemmon with a vertical pressure distribution like theirs. Yikes! No wonder our math and science scores are behind those in the developed countries!

The pressure at 4 miles above sea level (at 21,000 feet) averages about FOUR HUNDRED FIFTY millibars, not “13”, fer Pete’s Sake, and its still about 320 millibars at the top of Mt. Everest, about 5.5 miles above sea level. I guess these folks don’t do any hiking above about 1,000 feet above sea level. Might be too dangerous without an oxygen bottle in the atmosphere they’re making calculations for. (Looks like someone mixed units; English and metric in their calcs.)¹

Now, where was I?

Oh, yeah, this morning’s 500 millibar map… Note where the wind maximum is around a cold trough that is about to pass over us, the one that extends across Utah to Vegas. The peak wind is just about over us, and as the day goes by, it drifts farther south. So what, you say?

Check below where the moisture is at mountain top level, or around 700 millibars, 3 km or about 10,000 feet above sea level.

Temperatures and moisture at 700 mb, about 10,000 feet above sea level, also for this morning at 5 AM AST. See how the moist air at mountain top level is contained within the wind maximum at 500 millibars. Its just how it is here in the interior of the SW–doesn’t work so well along the coast or north of Salt Lake CIty, UT, or much east of Denver in the wintertime, but it is a pretty solid relationship for hereabouts.

Later today, that green area will be over us and there’ll be some scattered showers. Cloud bases will be high, higher than Mt. Lemmon, and so the precip is going to be pretty marginal. Will be very happy if even a few hundredths of an inch falls in Catalina this afternoon or evening. BTW, with the freezing level so low again this afternoon, soft hail (graupel, tiny snowballs) falling from these clouds is a certainty this afternoon or early this evening. (I’ve repeated some of this in the caption below…. Hmmm. Mind going.)

Here is the latest surface map of obs and infrared satellite imagery on top of the obs from the U of AZ. And, if you look out the window now, adding this at 6:45 AM, you’ll see the first clouds with this trough, likely good enough for a bit of sunrise color here in Catalina.

5 AM AST this morning. Good thing this trough and its minimal amount of moisture is swinging over us in the afternoon since a nightime passage would not have the scattered glaciating Cu and small Cbs we're going to see later today. — 5 AM AST this morning. Good thing this trough and its minimal amount of moisture is swinging over us in the afternoon since a nightime passage would not have the scattered glaciating Cu and small Cbs we’re going to see later today. And, by the way, the skies should be real pretty, too; big long shafts of virga falling from high based convective clouds. And, as you can see, some jet stream layer clouds–Cirrus, high Altocumulus in advance (near tip of arrow at bottom. Likley another day for lenticular clouds before the cold core gets here. Lots to look forward to today!

What’s ahead? Storms

Storm world, that’s what’s ahead because we’re in the bowl now, the trough bowl, resulting intermittent periods of storminess, broken by deceptively nice weather for several days; the latter, times of some trough fakery, one that make you think the “bowl” is gone. But then its BACK! So, don’t be afraid when the weather turns nice again after today.

Here is a sequence of maps from IPS MeteoStar ones that document what I am trying so poorly to explain, the overall spell of storms that we’re in, where one cold trough after another is drawn to Arizona like metal filings to a magnet. First the “interruptus”, now on deck, a map for about five days from now. For some reason, I put all of what it means in the caption.

Valid February 16th at 11 AM AST. No trough nowhere near Arizona. In fact, it looks like the trough bowl might be relocating to the Ohio Valley down to Natchez, MS. This is pure trough "trickeration", the latter a term used in football for trick plays where somebody looks like they're doing one thing and then they do something entirely different. So at this time, you're going la-dee-dah, no more storms, just nice weather now for quite a while and at the same time read about bad storms and cold in the eastern US. But you'd be so WRONG, as we like say around here. — Valid Saturday, February 16th at 11 AM AST. No trough nowhere near Arizona. In fact, it looks like the trough bowl might be relocating to the Ohio Valley down to Natchez, MS. This is pure trough “trickeration”, the latter a term used in football for trick plays where somebody looks like they’re going to do one thing and then they do something entirely different. So at this time here in Arizona, you’re thinking, “la-dee-dah, no more storms, just nice weather now for quite a while”, and at the same time reading about bad storms and cold in the eastern US. But you’d be so WRONG, as we like say around here. Look at that trough coming into the Pac NW. Guess where its headed? By the time that one gets here, you’ll realize that you went for the “fake”, and that all is not well weatherwise in Arizona, and more troughs after that one piles on top Arizona, bringing bountiful late winter rains, one after another. Finally, you go back to Michigan, you can’t take it any more, because you only came here for the good weather, not to stay and be one of us for the whole year….

Valid for 5 PM AST, the 20th of February. Now look who's bowlling! Its Arizona! Lot of great rain foretold with this one. — Valid for 5 PM AST, the 20th of February. Now look who’s bowlling! Its Arizona! Lot of great rain foretold with this one.

Valid for 5 AM AST, Sunday, February 24th. More rain on the doorstep.

Valid for 5 PM AST, Tuesday, February 26th. The grandaddy, the Big Bopper, a crescendo of troughy-ness occurs.

In conclusion, and remembering that these exact depictions above are not going to be realized as such, they will vary in intensities and positioning; nevertheless, the prediction from this keyboard is that February 2013 will have ABOVE NORMAL precip in just about all of Arizona due to storms that occur in the last 15 days. I am really happy for you, and its always great to conclude things like this, conclusions that bring so much happiness to others.

The End

————————

Mr. CMP, in a twinge of conscience, realizes that the error he goes on about today is one that he himself would like have made during his struggles in math and physics in HS and college.

Diabatics and snow

Its not about L. Ron Hubbard…..but we will try to be “clear” about what happened yesterday morning.

The short of it: when its snowing hard above you, the snow level drops. So, when yesterday’s well-predicted-by-all (models, humans, etc.) frontal band turned out to produce heavy snow above us, the snow level dropped to levels that were lower than expected (below 3500 feet elevation). Those big flakes take longer to melt, chilling the air to the freezing point as they fall and melt. So, down goes the freezing level for a short time during the heaviest precip. When the heavy precip ends, the freezing level moves up again.

We call this lowering of the snow level in heavy precip a “diabatic” effect, maybe get into the effects of enthalpy of fusion, too, because when we miss a forecast, we want use some jargon to make it sound like a very complicated process occurred, one that only Einstein could have anticipated.

Anyway, the diabatic effect yesterday involved heat transfer from the air to the melting snow; melting sucks the life out of the temperature because work is involved in melting snow . Often a little isothermal layer (temperature is steady with height) is present in the atmosphere when light, steady snow is falling in the layer where the snow melts into rain before reaching the ground due to this same effect.

BTW, there was a U of WA IMA Department of Weather softball team called the “Diabatics”. I insert this as a smile-producing distraction to get you off the thought of error.

I’m guessing the media weathercasters were all over “diabatic” effects as well yestserday.¹

—————————

The precip

Got 0.26 inches, 1 inch max depth of snow here at the house, missed “middle ground” prediction of 0.23 inches by only a slight amount. However, there was 0.36 inches, 1.5 inches of snow at a Sutherland Heights gage.

It was so great to see snow just sitting there, melting away slowly on ground in the desert yesterday and on those new grasses and weeds trying to spurt skyward in our droughty winter (so far). For a wider look at the precip totals, go to the U of AZ rainlog site here and input February 8th because even though the precip fell on the morning of the 9th, by convention for the U of AZ, its assigned to the prior day, which is the 8th in this case. If you do go there, you will see that for the TUS region, those areas north of Pusch Ridge got a quarter to a third of an inch while south of Pusch Ridge, totals were far lower. Lucky us.

The most I saw in 24 h in the Pima County ALERT gages as of 5 AM morning was 0.39 inches at CDO wash, northeast of Saddlebrooke.

Might not have been so great for the free range cattle, several of which were gumping down cholla buds as I drove along Equestrian Trail Rd! Ouch! Apparently that snow cover was just enough to prevent them from eating the dry grass out there.

Here are a couple of belated snow shots for your files:

9:01 AM. The Catalinas from Equestrian Trail Road. Trail Road? Hmmmm. — 9:01 AM. The Catalinas from Equestrian Trail Road.
Trail Road? Hmmmm.

SONY DSC — 9:01. Arizona “Christmas tree.” Cows like’em. Kind of fun to have one of these in the house in a pot, put a LOT of artificial snow on it, and then ask out-of-towners who’ve never seen one of these cacti if they wouldn’t mind helping out by putting some decorations that you’ve just bought on it.

Yesterday’s clouds and precip

They were again tremendous, when combined with the Catalinas, Tortolitas, and our deep blue skies! Took too many photos again, more than 200! Hard drive filling up fast!

After the slow dissipation of the stratiform deck in the morning, lifted and thinned, as was happening in the first photo, the Stratocumulus underneath that higher layer gradually dispersed into Cumulus clusters, and with the freezing level so low, ice readily formed in them.² Scattered showers developed by mid-day, and most, in the early going, produced graupel, tiny snowballs, soft hail or snow grains (really tiny ones).

The best CMJ’s out there no doubt rushed out before those little snowballs melted and were treated to the sight of “conical” graupel, cone-shaped little snowballs. Conical graupel, which is kind of comical-looking because it looks like a little, pointy clown hats, forms when an ice particle, say a plate-like crystal in a cloud consisting mainly of supercooled droplets, falls face down. The one side facing down the whole way, with the cloud droplets hitting on that one side, freezing as they do leading to that space shuttle entry vehicle shape. Kind of fun to see them and think of that ice crystal falling face down like a clown, and then it ends up looking like a clown’s hat! Quite funny. Hence, the nickname, “comical” graupel. Here’s one that fell on Catalina yesterday for your edification:

12:38 PM. "Comical graupel. You'd look so funny wearing a great big hat like this, maybe with a clown face! — 12:38 PM. A great example of “Comical “graupel. You’d look so funny wearing a great big hat like this, maybe, too, with a clown face!

Some cloud shots:

10:37 AM. Stratocumulus clouds hug the tops of snowy Samaniego Ridge.

11:15 AM. Snow showers first begin to form in modest Stratocumulus clouds NE of Saddlebrooke (precip can be on the horizon seen just above white roofed house in foreground.

11:53 AM. Let the graupel begin upwind of Catalina.

3:55 PM. Much of the best shots have not to do with storms but with the lighting on our fabulous Catalina Mountains associated with passing clouds on days like yesterday.

6:06 AM. Virga and the lowest cloud bases of a line of Stratocumulus clouds hovering over Oro Valley just after sunset. — 6:06 AM. Like a wind blowing on embers in a fire, virga and the lowest cloud bases of a line of Stratocumulus clouds hovering over Oro Valley are reddened just after sunset, producing another breath-taking Arizona sunset.

I could go on and on with more photos I liked from yesterday, but must close. Haven’t looked at a single prog yet!

The weather ahead

Looks like tomorrow will be a lot like yesterday afternoon (no rain/snow band likely), cold cumuliform clouds with afternoon virga and showers here and there, graupel, soft hail occurrence is a certainty from some of those clouds, followed by a nice recovery in the temperatures for a five day or more spell before the next winter onslaught of storms in the 10-15 day range from now (20th to 25th of February) hits. Hope they do. Those storms are “moderately” supported in the NOAA spaghetti plots.

Let me titillate your rain bucket with this forecasted behemoth on Monday, February 25th:

Arrow points to Arizona. From IPS MeteoStar's rendition of the WRF-GOOFUS model. — Arrow points to Arizona. From IPS MeteoStar’s rendition of the WRF-GOOFUS model.

The End!

—————————————————————-

¹It is also interesting that CMP, writing that the temperature would fall “15-20 F” in an hour after the front passed and rain started, did not realize that “15-20 F” minus the temperature of say, 50 F, at the start of the rain, leads to snow falling, fer Pete’s Sake! Kind of an arithmetic oversight.

²Not sure why the Beowulf Cluster at the U of AZ did not have scattered showers in the afternoon around Catalina in that 11 PM AST run I looked at–would have to be a problem in the model microphysics or the forecast cloud depth being too shallow.

Jet stream band of clouds delivers a sunset to remember; its snowing now…

at 6:30 AM…

The sunset? This one:

4:18 PM. Near stationary band of high and middle clouds, clearing to west. — 4:18 PM. Near stationary band of Cirrus, Cirrocumulus and Altocumulus emanating from beyond Kitt Peak, with a “pre-storm clearing” to west sets the stage.

6:06 PM. More overhead and zoomed view of the phenomenal ribbed structure in those clouds. Had never seen this before, waves in the flow spaced like this ("undulatus" as we would term it). — 6:06 PM. More overhead and zoomed view of the phenomenal ribbed structure in those clouds. Had never seen this before, waves in the flow spaced like this (“undulatus” as we would term it).

Raining pretty good now, 5:01 AM, thank heavens. Now, to get that bottom prediction of 0.08 inches… Always worry when foretellling rain amounts. Over is good, under is awful. Can’t look at radar, either, which would tell me what’s just ahead. Just listening to it on the roof, sort of “enjoying” the suspense in the morning darkness.

Back to the clouds at sunset… Would tell you how high they were, except that they were misssed by the TUS rawinsonde balloon. It appears it went up outside and ahead of this little moist plume up there, but indications and my own estimate, and even though these clouds were termed “Altocumulus” in the first photo, they were almost certainly above 22,000 feet above the ground (25,000 feet above mean sea level, or above 350 “millybars.”) ((That may seem exceptionally high for Ac clouds, but it happens^{1, excessive footnote, detracts from the main discussion and that’s why you put stuff like this in as a footnote because it doesn’t look so bad as just a little, itty bitty number. There’s a period just below this in case you lost trackl}.

5:23 AM: Oh, my gosh, temp down to 35 F now! Wow.

On to some an illustrative figure of what was going on last evening, this from the Weather Department at the University of Washington, a 300 mb map. There’s a tremendous number of arrows and amount of writing on it, I hope that’s OK. It is kind of pretty, though, with all the colors on it.

300 millibar (30,000 foot level in the atmosphere) for 5 PM AST yesterday, the 8th.

Back to stream of conscientiousness: 6:11 AM. Quiet now, no rain. Only 0.06 inches so far, need two more. What the HECK is happening? Went out with flash light and its SNOWING! Oh me, Mr. CMP wasn’t thinking snow at 3200 feet today! Dang. But, like the map above, it could be quite pretty, likely precip will get over 0.08 inches now, too. Just won’t go in gauge and tip bucket until later when it melts. Temp now 33.5 F in light snow. Was 47 F before front and rain began to hit, so its down almost 14 degrees now. No wind, either.

Rest of today; now looking at data:

Looks like precip, snow melting on contact mostly, maybe a skiff to an inch at most, will continue for the next 3-5 hours before the clouds lift into a higher layer of Stratocumulus toward mid-morning (this from the Hollerith technique illustrated a couple of days ago). Probably will be some gorgeous Stratus fractus along the snow-covered Catalinas, too. Later the sky should devolve into scattered to broken coverage in Cumulus and shallow Cbs with virga and passing light showers, probably will barely measure. Now, lets look at the U of AZ model and see if this has ANY credibility…. Seems to be about the same, rain/snow precip ends by 9 AM here in Catalina. However, no passing showers are indicated in this model after that.

Should be a memorable day with the Catalinas in some snow again, and passing clouds and shadows on them.

The End.

———————————-

¹During our (Cloud and Aerosol Group’s study of aircraft-produced ice holes and canals in Ac in the early 1980s when Reagan was President and just after he fired all of the air traffic controllers, we were able to talk to guys at the Air Traffic Control Center in Auburn, Washington, working the jets coming into SEA-TAC! We were able to get from them real time heights of Altocumulus cloud layers in which holes or canals due to ice formation occurred due to an aircraft. While Mr. Cloud Maven person has won cokes off pilots who questioned his estimates of how high clouds were, who then, following a bet, took off and measured them, even HE was surprised at how high some Altocumulus cloud layers were. Some were well over 20,000 feet above ground level! In the days before heights were measured by machines, now up to 12,000 feet above ground level, it was almost routine for human ground observers at weather stations, when seeing Altocumulus clouds, to put down “12,000 feet” or “15,000 feet” above ground level for the estimated height of those clouds in aviation weather reports. Older pilots will know this, having heard the sequence in verbal “transcribed” aviation reports, something like, “Five thousand scattered, estimated one-two thousand broken, two-five thousand overcast….” Oh, yeah, that’s how it was so long ago.