Peachy!

Sunset, anyway, even if only a few drops of rain fell last evening.   Nice lightning to the south, too, 9-10 PM.

However, yesterday afternoon, we had some examples of really “bad” cloud bases.  They were trying to make me think we might have a repeat of the day before’s cloudburst by darkening themselves up.  While Mr. Cloud Person (me) was almost fooled, he wasn’t really at all.

Lets replay yesterday afternoon….  Here in the summer, of course, we look to the east (NE through SE) and over the Cat mountains for guidance in storms, for prognostic purposes, not to the west during the summer rain season.  This is especially true in the late afternoon and evening when our chance of rain is peaking.  We often see the sky loading up with dark cloud bases somewhere over there.  Its pretty darn neat, and can happen in only a few minutes. These are often storm complexes, clusters of Cumulonimbus clouds,  that done sprung up over the White mountains or other terrain earlier in the day, and are being re-inforced/ are propagating westward by the outflow winds that accompanied them.  Those winds near the surface shove the air above it upward creating new clouds.  Sometimes we’ll see an especially low cloud on the more moist days, called an “arcus” cloud, a ribbon of cloud that rides above and near the front of the outflow wind.

OK, those clouds that feinted rain late yesterday for a time.  First, we’ll start when you were getting really excited and running around telling the neighbors that, “Hay!” (a lot of them have horses), “It looks like it might rain again this evening!  Look at those clouds over there over the Cat mountains!” You’re loud, but you’re not exactly screaming, since you are holding back a little; you know about those “fakery” cloud situations where the bases fall apart, don’t congeal into a large, solid mass.   You’re holding back just that bit of excitement.  I am proud of you.  Here’s what got you going:

This is looking pretty damn good, but its not there yet.  Why?  First, while there is an OK, keep an eye on base over the Cats, its got some thin spots, some brighter areas near the darkest areas.  Note the little bright spot in the middle of the closest larger base.  Fakery right there.  You know this cloud is not going anywhere in spite of its overall darkness underneath.  Also, you really don’t see any sharp edged indicating newer) rainshafts.  Blobs of smooth sky, even with rain, are associated with dying cloud masses, and if that’s what coming at you, you may not get ANY rain because it may have all fallen out before it gets to you with our slow summer winds up “top.”

The next photo is 20 minutes later.  Its look that bit better, but in all that time, no rainshaft has dropped out of this stuff.  Nor has the cloud complex gotten much closer.  No rainshaft equals no cloud tops colder than -10 C (14 F) above that base (about 20,000 feet yesterday), and that means while dark, the clouds are not terribly deep.

Why aren’t they yet?  Not enough push underneath, warmth, etc.  This lack of progression is of some concern.   Of course, this can change in a hurry, but increasing concern develops that this could go bad.  A lot of time with not much happening is quite bad, really.  The next photo is about 6:19 PM.  While the cloud base is looking formidable, still pretty solid, a rainshaft has STILL not developed indicating cloud tops are going nowhere, man!  Dammitall, to cuss that bit! Starting to get that “rejected” feeling:  “Well, you thought I (that vaporous mass) was going to do this, but I’m not.”  You think about the screaming you did at your neighbors…  Could be embarrassing. In the last photo, ten more minutes later, its over, finished.  The cloud base has shrunk in size, is starting to look raggedy, still no rainshaft, etc. etc.  You begin thinking of this cloud fakery in terms of spheres of equestrian processed hay.  But, you did hold back that bit, you didn’t go all out because you had seen this happen before.  I am proud of you.

The End.

Yesterday’s Catalina-centered blast dump: 0.83 inches; 0.53 in 16 minutes

Nice weather we’re having lately.   Nice desert greening we’re having now, too.

What a day yesterday was!  Look at the sunrise view of Altocumulus at the start of the day.  And, too, how about some neat patterns before all the mayhem.  What a day, to repeat.

Yesterday’s blast and dump that struck just after 2:30 PM yesterday can be seen in a side view here, courtesy of the University of Arizona Wildcats Department of Atmospheric Meteorology.

Watch those dark cloud bases move over the southern portions of the Cat Mountains at 2:30 PM in this time lapse film!   Pretty dramatic, and also see how fast a cloud can drop a load of precip its been carrying in some of those around Tucson yesterday.

Below is what those same clouds looked like rolling over the Cat mountains toward us from our Catalina vantage point.  This was pretty darn exciting to see!  Why?

First, that dark line of bases was streaming toward Catalina from Table Top peak.   Next,  the bases are pretty large, meaning a there is pretty large area of updraft, and 3) MOST importantly, the bottoms looks solid, no bright spots interspersed among the dark base telling you that the updraft has holes in it.  A solid, contiguous base like this suggests a good AND contiguous updraft, and a LOT of water is being condensed above those bases.

Can things change and holes develop even at this point?

Yes, have been horribly disappointed a time or two when that has happened, and when it does,  its kind of like the beginning of a love affair you thought was going to be a good one but goes  “south” all of a sudden because you made some assumptions based on too little “data” and other misinterpretations due to wishful thinking and delusions and then you find out that those assumptions and perceptions were incorrect and you REALLY were delusional cum laude.    How painful is that?  But then you have to “man-up”,  as we say today, and pretend that nothing happened…or you’ll lose face.  Yes, I have had to do that with some cloud bases that have let me down.

Or taking another tact here for sports fans, a cloud base that falls apart is like a seeing a running back breaking into the open, with a clear field ahead.  Everything LOOKS good until he trips and falls at the 10 yard line.   You’re so upset, you go down to the Golden Goose thrift shop and buy a pair of ladies’ used tennis shoes and send them to the miscreant running back as a way of pointing out your displeasure.  You don’t want to admit you were wrong in your “a priori” assessment that a touchdown would surely be scored.

Well, you get the idea.  It can all go bad just from looking at the cloud base and making an “exterior”  assessment because you really don’t know what’s happening “above” (as in people).  So, you have to “hold back” your emotions just that bit to keep from being hurt by a nice “cloud base.”  Was I talking about weather somewhere in here?  OK, back on task.

But that cloud base yesterday did not fall apart; it did not disappoint!  Rather it remained solid until that magical point that all that water/hail/graupel up there above the bottom of the cloud begins to shoot down, often in strands or filaments.  The strands or filaments are almost always due to hail or graupel shafts.  Hereabouts they are likely to have melted into large drops on their way down.  (When flying through these kinds of clouds, as the writer did for many years with the U of WA Cloud and Aerosol Group, flying through those miniature shafts of hail/graupel (soft hail) was like someone throwing a handful of rice at the pilots window.  They were only tenths of a second in duration, maybe 10-30 yards (meters) wide.   Its still not clear what cloud “microstructure” and circulation leads to such tiny strands within large clouds.  Uh Oh, getting deep here.

Check out the next couple of photos, especially number 2 and 3.  For maximum precip excitement, I would have, and I am sure you, too, wanted to have been about 1 mile farther toward that base as the bottom drops out.  That’s where the largest raindrops, hail or graupel are going to be.  Of course, all that water is going to shove a lot of air out of the way, and that’s why we saw those momentary blasts of wind to 50-60 mph, at least right here.

Here’s a map of the local area rainfall, thanks to the U of A rainlog organization.  It will show you how well we did relative to the rest of Tucson.

 

The End.

“Back in Black”, cloud bases, that is

Few people know that Angus Young, lead singer for AC/DC, was quite the weather nut and many of his songs, such as “Back in Black”, are actually about clouds and storms.  Thought you’d like to know so that when you get your old AC/DC albums out, they’ll have a little more meaning to them…  What about the AC/DC song, “Hell’s Bells”, you ask?  Its interesting that you have asked me about that.   Here’s the story behind that one:  well, that was about a forecast of rain that didn’t materialize there in Australia. Its mostly desert there, like here.  Mr. Young was pretty upset about it, apparently.

Some cloud bottoms for you from yesterday.  Nice to see the return of the summer rains.  Only 0.07 inches here, but I was quite happy to see that heavier showers fell elsewhere,  all around me,  in fact,  and perhaps in droughty areas that needed more rain than I do (face turning red, fist pounding table).  No, it REALLY was good to see others get more rain than me, and watch the summer “spectacle of the rainshafts” way off in the distance underneath those Cumulonimbus clouds.  I like spectating rather than participating, that is, being inside those rainshafts (face turning red, fist pounding table).

On with the picture show:

 

 

 

 

 

 

 

 

That sunset scene last evening;  the slot of clearing that allowed the yellowish sunlight to bath the rocky faces of the Catalinas, followed by sunset color in the underlit clouds overhead. Can one’s thoughts not shift away from self and problems, to the joy of being here in this special place?

The End.

Lenticularis in July?

Altocumulus lenticularis, to be exact.   Of course, as the discerning, eruditeful cloud person that you have become, I didn’t need to tell you this.

Well, yep, here they are, courtesy of the U of A Wildcats website. And, if you missed them locally near Catalina, here are a coupla shots.  In this movie, you will see sliver clouds that appear absolutely motionless above the Cat mountains.  Those sliver clouds are “Ac len.”   Cloud droplets form on the upwind side (to the right) and evaporate on the downwind side (on on the left) in this film.  They are stationary because they are in a bump in the airflow caused by the mountains, and since the mountains aren’t going anywhere very fast, the bump remains in the same location as long as the winds are steady.  As the air moistens and dries out, those Ac len clouds can expand upwind or disappear since the bump or hump in the airflow is bigger than what you see when the air quite dry.  I will get my 1o1 cartoon of this situation out. (I actually taught 101 one summer at the prestigious University of Washington’s Department of Atmospheric Sciences.  Poor students!  Those weather jokes!  Poor University, too.  I had,  and have, only a Bachelor’s Degree and I am sure that this Lectureship caused a decline in Washington’s accreditation that year.  As you know, to teach even the most simple class, a University must have Ph. D.’s. Experience gained in research and in the “school of hard weather knocks”, etc.  have no real impact on a university’s accreditation as we know1.  Gotta have the big Ph. D.  Whining here, and off task, but it feels good.

Lenticulars are an odd site for July.  Why?  Because lenticularis clouds are associated with stronger winds aloft AND a modicum of moisture and we don’t usually see BOTH in July.   However our influx of tropical air, not fully arrived yet, is associated with a stronger than usual flow pattern.  The NWS rawinsonde (balloon) sounding indicated winds of 30-35 mph at cloud levels.  Here’s what the sounding looked like as depicted by the University of Wyoming Atmos. Sci. Dept.:

Where the dark lines pinch toward each other are where clouds might have been.  Since at sunset some of these Ac clouds shed ice, you would have to guess that they were NOT at the lower level where the lines pinch in  (“600” mb or 14,000 feet or so above sea level) but rather near 20, 000 feet (or at the “450” mb level or even at the “325” level, close to 30,000 feet (!) that highest point where the lines pinch in showing a moist layer.

Quitting here, looks like first chance for rain today after the interruption of the summer rain season….  Excellent!  Gorgeous sunrise “blooming” now, too.  Ac opacus with scattered virga.

 

 

 

 

 

 

 

 

 

 

Below a simple diagram modified for the Catalina mountains showing what the airflow might be like under strong, semi-moist westerly flow with Ac lenticulars occurring downstream from the peaks:

Catalina summer rainfall 1977-2010: there is no trend

OK, no fooling around today with HUGE text boxes with book length ramblings, just the facts:

Catalina inches of summer rain

These data again mostly due to the friendly folks Wayne and Jenny down at Our Garden here in Catalina.  Since they are open today, Saturday, it would be great if you went down and bought everything they had as a gesture of appreciation for collecting weather data over so many years.  Its really invaluable since there are no other data in this area.  The data for 2008-2010 are from a gauge here near  where the pavement ends on E. Golder Ranch Drive, or at a somewhat higher altitude than the earlier measurements.  Note the lack of a trend, not getting droughtier in the summers. Yay!

Its always fun to look at past data and dream about excess wetness, as we had here in for two summers in the early 1980s.  Imagine, in 1983,  June through September logged over 17 inches of rain!  Our annual average is about 17.5 inches here in Catalina.  Note this annual average is considerably more than locations that are relatively close where in general, averages such as at Tucson are closer to 12 inches per year.

Clouds!

A welcome sight was a few evening Altocumulus clouds creeping past the Catalinas yesterday as tropical air begins making its return.  Mods have rain in the area beginning tomorrow and continuing for several days at least thereafter.  We’re just beginning the height of the summer rain season (sorry, I can’t say “monsoon”;  monsoons are in India and SE Asia.   We don’t call hurricanes,  “typhoons” do we?  Never mind;  just don’t like “monsoon.”  Its a quirk.  We all have them, so I don’t feel bad at all having quite a few quirks.)

 

 

 

 

 

 

 

 

“This (dry air) will not stand”

Pretty tough day, yesterday.  After a few altocumulus floccus shred clouds around dawn until around 7 AM, the sky became absolutely, totally clear.  Once again, I did not expect this.  (There are a lot of surprises in life when you are a weather forecaster.) I thought shirley1 a few small Cumulus would form later that morning.  Nope.  Absent clouds,  I had little to say to my riding partner yesterday on our mid-week ride.  I think she took it as a pleasant departure from the continuous stream of cloud commentaries she normally experiences. (hahaha, sort of).  It was wondrous seeing the carpet of green erupting from oven baked soil of this past late winter and early summer.  That has to be one of the truly great things about living here, that second greening when the summer rains come.

However, I am heartened by the presence of Cirrus from the tropics this morning and a clear push of tropical air back toward Arizony already,  as seen in the water vapor loop here.  Look to the south of us and see that massive “army” of water molecules (that whiter area covering northern Mexico) push westward against the bad dry air (darker regions) from the Pacific that invaded us yesterday.  Fantastic.   Maybe a storm chasing trip to Douglas tomorrow is in the cards.  I really dislike a day without thunder in summer! (Perhaps I should have moved from Seattle to Tampa-St Petersburg, the latter the lightning capital of the US, instead.)  Just kidding, though it would be fantastic to be there in June!

Mods say that the summer rains will begin recurring maybe as early as Saturday in the vicinity of Catalina.  How fine that will be.

 

The End

1I once knew a Shirley.  We were just friends, though, nothing lurid that’s worth re-tellling here.

“Groundhog Day” all over again

If you mainly focus on going to movies about weathermen, you will remember this classic along with Steve Martin’s “LA Story.”   Bill Murray, the weatherman, is condemned to live the same day over and over again until he gets it right. Since yesterday was a near repeat in many respects to the failed rain day of Monday, this seemed like an appropriate title.

1.   OK, morning:  some really nice Altocumulus castellanus (miniature Cumulus clouds with flat bottoms) and “floccus”–raggedy bottoms1. These indicate a nice drop in temperature as you go upward in the “middle-levels” (around 10-15 Kft above the ground) and that in turn helps the formation of thunderstorms.

2.  Clouds topping Mt. Sara Lemmon again indicating a grade of  “juicy” moisture hereabouts.

3.  Very early thunderstorm, first thunder heard a 10:40 AM in a mountainous Cb N of the Cat Mountains (shown below in its, “Cumulonimbus calvus” stage;  top is ice, but is not yet CLEARLY fibrous, striated).

Seemingly all is in place for large thunderstorms to be scattered hither and thither later in the day, rumbling and banging around, scaring cats and dogs with lightning sabres, blinding rain, puddles in the road, TEEVEES out of whack, missing your favorite show, “TV party tonight2” canceled.  OK, enough dramatics and songs2.

But it didn’t happen did it?  Why not?

One of those very circulations foretold in the numerical models slipped over us yesterday during the day, and as these circulations do (you can see it here in this long “water vapor” loop)-you’ll need a broadband connection to see this.   You’ll see a miniature low spin into SE AZ from Sonora, MX, late on the 11th-early yesterday morning.  The darker area rearward of this circulation represents horrible drier air in the mid-levels especially.    The whole point of this loop is to show that drier air moved in and desiccated the otherwise growing Cumulus clouds following the passage of this micro low above us.  The very raggedy tops of our afternoon Cumulus clouds was an indicator of this extremely dry air that did not allow them to explode upward with the afternoon’s heating.

You could see this happening since,  in a homogeneous air mass, there would be no full blown Cumulonimbus clouds just to the north semi-circle of Catalina, and only weak Cumulus with ragged tops spearing that dry air at the same time in the southern semi-circle from Catalina.   I started to get depressed.   Something was going wrong, the air was getting too dry upwind.

Still, the there were enough Cumulus and Stratocumulus around at sunset to produce another memorable sunset.  Maybe that’s reward enough.

The End.

 

 

1distinguishing between the two is a bit silly IMO.

2Who can forget the Black Flag tune, “TV Party Tonight”?  “We’re gonna have a TV party tonight!  All right!”

Untitled

Kind of sad today.  Too sad to think of a title.  Thought you’d like to know that.  Yesterday was once so promising.  I almost had it all.   I was SO happy to see clouds topping Mt. Lemmon at dawn, and then later, cloud bases down on Samaniego Ridge east of Catalina.  How warm those cloud bases were (maybe 15 C)!   And how full of condensed water those Cumulus and Cumulonimbus clouds later on were going to be!   I opined from this very blog that we would have a big day in the area.

As the morning wore on, it was as though my thoughts were magical and could make things happen by only thinking them, the Cumulus that morning churned, roiled and boiled upward as though on command. The first shot below shows one of those boiling,  ominous clouds so full of promise at only 10:19 AM.  It was so GORGEOUS!  Then, but nine minutes later, in the second shot, a turret had powered up to through the “glaciation level”, where the highest portion (uppermost part) had become cold enough to convert to ice right before my eyes (that top 25% frizzy part).   As you know, this means that the Cumulus congestus had become a Cumulonimbus “calvus” with a strong rainshaft.  Minutes later, the “capillatus” stage was reached and an anvil began spreading northward!

Thunder was heard by 10:29 AM! This was perhaps the earliest occurrence ever for thunder  over the Catalinas as the day’s new Cumulus buildups began.  Really, I could not praise myself enough for having looked out the window at dawn for a few seconds, and then magically deduced from a perusal of the sky what the cloud future would hold.  It was really pretty remarkable; daring even.  I looked forward to the rest of the day.  Maybe Catalina would get another inch of rain from some massive complex that afternoon or evening.

But then things began to go bad.  It began to get cloudy, though admittedly there was a brief shower that brought 0.01 inches (third photo).   You could see that with the increasing “stratiform” (flat) cloud cover that things were going “south”–not really “south”, its just a figure of speech indicating a downturn.  The clouds were mostly going north.

There were no more new Cumulus clouds building up over the Catalinas due to this heavy cloud cover.  It “sprinkled-its-not-drizzle” for a coupla hours.   Seemed like Seattle rain, as a former Seattetonian.  Why was I experiencing Seattle rain in Catalina, AZ?  Finally, the afternoon ended dismally with this heavy overcast of Altocumulus opacus.  I usually love Altocumulus clouds, but not yesterday.   They were offensive to me.  I had been humbled thoroughly and completely; felt like a mashed down Cumulus humilis at the end of the day.  But then, humble is good, isn’t it?  I began to feel better that I had been wrong because I learned something and was now humble.

At least the day ended up with a pretty sunset due to those obnoxious Altocumulus clouds combined with the “topography” of a distant thunderhead that caused rays in the sun’s light to appear in the “cracks” of that distant cloud top.  Those rays are called “crepuscular rays”, as we weatherfolk call them.   But a friend recently told me that they were also called “stairway to heaven”; very poetic and much nicer than “crepuscular rays.”  Enjoy.

Not speculating on today’s weather except that we should still have a chance for a big day here in Catalina.  (After the word, “except”, you can say almost anything.)

The End.

Too much “Altostratus cumulonimbogenitus”

Yes, that really is a cloud name;  kinda silly really.  Oh, well….

First, since there wasn’t enough rain here to make me happy–there wasn’t ANY in Catalina yesterday, I thought I would start out by making people feel better with a “Clouds R Fun” photo from yesterday.  Here are two “puppy” clouds, side by side, ones I thought might grow up to be Great Danes, but didn’t.  Still, they’re awfully cute anyway.  You just want to cuddle them.

Now that we’re all feeling that bit better thinking about puppies, we can move ahead to solving what happened and why Mr. Cloud Person’s expectations of signicant rain in the immediate area were not realized.   If you are a really good sky watcher, off in the distance, large Cumulus and Cumulonimbus erupted explosively well before noon.  I was so happy!  This could be a “totally awesome” day, I thought!   Look at these photos taken  at distance “Cbs” to the south of Catalina before Noon.

In the first shot taken at 11:45 AM, to the right, a full blown “Cb”, to the left partially hidden by Pusch Ridge, Cumulus congestus clouds.  Now look at the next photo in that same direction.   That group of Cumulus congestus beyond Pusch Ridge have exploded into a massive Cb with a giant anvil (“incus”)!  Areas near Green Valley, toward which these photos are taken,  got 1-1.5 inches.

But there was something pernicious going on right in front of my eyes; those huge anvils (“inci?”) that were being ejected by these explosive thunderheads.  Those can actually be a BAD thing because if they spread over the whole sky, they tend to kill off the Cumulus clouds underneath them by shading the ground, often teamed up with a subsiding air pattern.  While the air rushes upward in hot spots in these complexes, there must be compensating downward and cloud killing motions somewhere around it. It seemed to be the case as that huge complex S of us yesterday afternoon fizzled out and left a giant mass of—you’ll want to exercise you tongue before trying to pronounce this—“Altostratus cumulonimbogenitus” spread over the sky in the afternoon (last photo of a Seattle-like sky over Catalina). This smooth layer cloud is really just the remains of thick anvil clouds from all those “Cumulonimbus capillatus incus” clouds earlier in the day to the south of us.

Were there huge storms relatively nearby yesterday?

You bet!  Take a look at this loop from IPS Meteorstar, one that combines radar echoes and shows the spread of the thunderstorm anvils, the “whitest” and coldest topped clouds in this loop.   Notice what happens near the southern Arizona border about the time the second two photos above were taken.  Just an explosion of grouped thunderstorms with their flash floods that we call “meso-scale” complexes.  With luck, a bit different weather pattern, we could have been under that. Darn.  We’re still having conditions to produce large severe storms.  Maybe today will be our day.

Here’s are the cloud signs for today for why it is especially ripe for high rainfalls:  Its moist through about 40,000 feet above the ground and the cloud bases are LOWER today than yesterday.

How could you tell that just gawking at the sky and our Catalina mountains?  Well, you got yer Cirrus (high level moisture), you got yer Altocumulus (mid-level moisture) and you got yer Stratocumulus, some of which are topping Mt. Sara Lemmon (low level moisture)!

Now this last factor is really good in indicating the chances of 1-2 inch rains under the main shafts of our thunderstorms today–nothing too unusual, however, for AZ .  Lower cloud bases means warmer cloud bases, and warmer cloud bases in the summertime is like adding a furnace inside those towering Cumulus clouds due to heat released when condensation occurs.  And the warmer the cloud bases, the more water that is being condensed inside them.  Is anybody still reading this? Better quit here; I’m even getting saturated.

 

The End.