Cloud-maven – Page 82 – About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno

Black is beautiful

Here in this part of Catalina another 0.11 inches dropped from the sky in two weak, but great thundershowers yesterday afternoon, one that will help keep the greening of the desert coming on strong. As many of you know, my photographic niche is cloud bottoms, particular dark ones, and to me, beautiful, dramatic ones when rain or hail filaments begin shredding the air below them, followed by the dump.

Below are a couple of those bottom shots from yesterday. This cloud trucked off from over Catalina toward the SW and over Oro Valley/Marana where it began to rain.

SONY DSC — 3:55 PM. The bottom of a small Cumulus congestus (it was at least 6,000 feet thick, 2 km) at the time this photo was taken, trust me.

Later, two weak, but welcome thunderstorms rolled off the Cat Mountains from the NE, giving us 0.05 and then 0.06 inches in the second. Below, here they come!

Yesterday’s rain totals can be found here (rainlog.com) and with the Pima County Flood Control Network. Some areas in and near Tucson recorded over an inch again. How fine.

Today?

The dewpoints are higher, cloud bases are a bit lower, and so monster dumps in the area are VIRTUALLY guaranteed (never can tell exactly where they will be). However, conditions aloft are also conducive to larger shower areas than yesterday’s were, that is, large clusters of Cumulonimbus clouds are more likely today, meaning larger areas covered by rain, and longer durations of rain. Cool. You can get the “skinny” from the U of A model here.

Quiz

The weather ahead.

Rain in the area, the models say, every day for the next few days. Check here and with Bob (our local expert), who seems to be mad a lot, even titling his blog, “madweather.” I guess he’s not afraid, like some men, of showing his emotions. I get mad myself, but usually its when it doesn’t rain on me that day.

The literal greening of Catalina and its environs

Yesterday in the State Lands:

OK, enough about ME; what about the weather?

No rain today around here, according to our best model output, which, of course, is that issued by the University of Arizona Wildcats Dept of Atmospheric Meteorology. But tomorrow, oh yeah, tomorrow, its BACK!

The end.

The greening of July

Update at 7:17 AM: while mods had a dry day today (e.g., U of A yesterday), NWS has a much higher chance at 30% for our area today, and it sure looks like a higher chance. (U of A Beowulf Cluster mod not available this morning for hi res check.)

While trying to get through the next couple of predicted days with lesser chance of rain though it doesn’t feel like it right now at 7:17 AM, and after a disappointing 0.02 inches yesterday afternoon, I wanted to check the Arizona rain futures in two models, the N-viro Can U-ro (as we would write it today) and the USA WRF-“Goofus”, both spoken with affection, to see how much “green” they have for us. “Green¹” has been the chosen color for rain by meteorologists, a particularly colorful people, who as children had an extra wide assortment of Crayolas and colored pencils.

Both models have a LOT of green in Arizona during the next 6-15 days except, as noted, for today and tomorrow where rain is marginal.

Below, as example from the Environ Can mod result for the evening of July 22nd. Note green splotches in AZ, lower right hand corner (blue is very light rain; yellows and reds are heavier rains).

Along with the positions of rain here, in the upper left hand corner, is the forecast for where “our” big fat summer anticyclone is going to be on that day: centered way over the state where Dorothy used to live. The air circulating around that high, clockwise, is circulating moist air into Arizona (while baking Dorothy and a lot of other people in the nation’s mid-section). I love these maps and what they portend for AZ over the next week!

Below a sample chart for even farther out into the future from a rendering of WRF_GFS from IPS Meteostar for the evening of August 1st. There is still “green” in Arizona, this time around Yuma, and there has been green in Arizona every day! With our great start, it could mean that we will experience one of the wettest July’s ever in SE AZ! The droughty weather pendulum may have swung back to make things up to us.

How do we know such medium range forecasts are have a better chance than usual of verifying?

Of course, if you are a regular part of this blogpire, you will know the answer.

It comes from the NOAA Spaghetti factory. We meteorologists, not satisfied with one model run, like to mess them up at the start, and then look at the various “perturbed” model runs fro the 500 millibar level, and see if there is one “answer” that remains “strong”, still visible in the output amongst all the many contours of the wrecked ones. The middle of the troposphere, that domain where all weather occurs, is at about 500 millibars of pressure; sea level pressure averages around 1000 millibars (1013.6 millibars is the bottom of the “standard” atmosphere. We like to see what the pressure patterns are like in the middle because things clarify up there, that’s where you can find jet streams, those steering currents for storms at the ground.

OK, now the punch line, don’t laugh too hard.

Below is the (humorous) plot from NOAA based on last evening’s global data for the 500 mb level due to combining:

1) the model run using the actual measurements made around the world at 5 PM AST,

2) and along with that one run, many model runs due to inputing slightly erroneous data at the beginning of the run.

Many of you will see this as a “knee-slapper”, and it really is because its a faulty production with too many contours.

But, in spite of a faulty NOAA run, there is still some information about our “big fat anticyclone” and where the most likely position will be on the evening of August 1st, some two weeks from now. Believe or not, it is a powerful tool.

That likeliest of positions of our big fat anticyclone is that little dark spot over the Four Corners area mostly devoid of lines in this humorous output. On this map, the Four Corners area is straight above the yellow legend line segment. At left, a close-up of that Four Corners area with the fewest lines.

In the summer, Arizonans “need” to have a high in the middle of the troposphere to the north or east. And that’s where the signal is strongest, represented by a center of that high situated over the Four Corners area even when the model has been degraded by bad measurements.

So, in sum, look for lots of rain in Arizona overall during the rest of July. How nice, except when telephone poles are blown over, as happened on Sunday.

PS: I took a lot of great cloud scenes yesterday afternoon and evening, but you need to have an SD card installed in your camera before a photograph is recorded. So no photos. I hope this is a useful hint for photographers out there.

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¹“Green” in the meteorological color scheme of things, means rain, an area where the models think it will have rained is colored green as a rule. Green has been the choice of meteorologists for liquid precip ever since weather began, back in the early 20th Century at the Bergen School of Meteorology in Norway. Why did those Norwegian meteorologists with names like Bjerknes, Palmén, Holmboe, Godske, Petterssen, Rossby, Bergeron, choose green for rain? Just because.

Another dramatic Catalina weather day-the book

OK, this one’s a little long, lots of twists and turns in the weather plot before its over….but as the Arthur, I felt they were needed (that is so funny! 🙁

We’ll start with the “end” of the book; cut to the chase: the mods have another possible big day this afternoon, Check it out here.

The result of heavy rain in the Catalina Mountains late yesterday afternoon is shown below. These shots were about 2 h after the main dumps up there had occurred. Some neighbors and me was just standing around chatting, had come down to see if there was ANY flow in the CDO. Nope. But, since we were having a good time, kept on chatting. Then, the roar! (BTW, you could hear the Sutherland Wash roaring from about a mile away. Must’ve been something over there.)

Amounts around here in and near Catalina were generally between 0.4 and 2 inches, with the lower amounts here and up at Sutherland Heights, darn. You can see the Pima County rain table (here) and the U of AZ rain network totals here (they’re usually not complete until later in the morning). These are totals for the 24 h ending at 7 AM. You can also review yesterday’s cloud action in the U of AZ time lapse movie for yesterday, rated R for violence. Max totals in NW Tucson were over THREE inches!

Below is a review of yesterday, beginning with an attempt at some true art, one I’ve entitled for a possible museum showing, “Ants and Castellanus.” Remember, Altocumulus castellanus/floccus are a good indicator of an “unstable” atmosphere at the level they formed at. The ants, flying ones, tell you that there was good soil moisture, which is actually important in keeping the boundary layer air moist by replenishing it during a warm day. It was good seeing those ants in swarms like that, they seem to be having a lot of fun, exuberated by moisture, perhaps thinking of more soil moisture ahead.

So, in this ONE photo I took for you, you have TWO indicators that are suggestive of the day ahead; it might rain again¹. You could tell your friends things like this and sound quite wise concerning nature. Really something like this should be in the Farmer’s Almanac.

Frankly, while the best models we have available had quite the rain over us yesterday afternoon by 4 PM, it didn’t shape that way. It was still dry and not much going on. I am guessing that the colossal amount of rain-cooled air from the previous rain day kept the trigger point (the high temperature) for huge clouds a bit delayed, but it was only by about 1-2 hours! The rain arrived here between 5:30 and 6 PM. Pretty remarkable accuracy, never mind the bugs, when you think about it.

Often on days like this, where the atmosphere is primed for huge clouds, they go through cycles where it seems like all of sudden they putting themselves together, bases clustering for an upward explosion, but then a few minutes later, the whole sky looks in disarray, the bases having broken into small segments, tops of the clouds ragged. That happened a couple of times yesterday afternoon and so I wondered if the explosions would ever happen. Sometimes, in time lapse films you can get a sense of this as waves, gravity waves like ocean ones, in the atmosphere pass by with the clouds in films seeming to all fatten up at once, and then subside as the wave passes.

But then, it happened, all of a sudden, first an cloud on the west end of Tucson, south of us, which had been struggling, began massing, “shafting” (putting out multiple rainshafts), and putting out lighting. That was it, with the model background of massive clouds, you knew that this was it, the sky was going to go bonkers all over. With but a brief interruption, it did. I was beside myself snapping photos every few seconds, being out of control again with these stupendous scenes of transition and drama!

Here are too many:

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¹I would consult some computer models before taking that thought too much farther. For example, if the computer models are showing rain later in the day, and you’ve seen some castellanus and flying ants, I would definitely mention this proverb to friends, say, during a morning walk. Otherwise, keep it in your back pocket.

Is it India? Or is it Catalina?

Let’s have a contest, get the brain going.

With dewpoints hovering near, and even eeking into the low 70s in AZ, with giant thunderstorms complexing our weather with sudden stupifying downpours, one wonders, after all of these blogs, this “body of work” if you will, if the several people who comprise the Cloud-Maven blogpire, one that radiates from one part of Catalina to another, would be able to know where they were if they could be transported to the locations in these two sets of four photos. (BTW, all of which were taken by the present Arthur–hahahaha.)

OK, drum roll, insert photos here.

Two were taken at the Madras (now Chennai) International AP in Meenambakkam, Tamil Nadu, India, in September 1975, and the other two just yesterday afternoon in Catalina, where most of us live. Remember, there are mountains in India, so just because you see some mountains doesn’t mean its NOT India. Also, just because I mentioned two were taken in India first, doesn’t mean necessarily that they are the first two shots below.

OK, begin thinking and analyzing, maybe drink some more coffee.

OK, if you guessed the first two photos were actually taken in India during the REAL monsoon in 1975, you were right. That’s a friend, Venkateswaran, on the far right of the first photo admiring the arcus cloud ahead of the downpour.

The result of our “pseudo-monsoon”, which was a pretty good imitation of the real thing yestserday, shown in the second set of two photos, was another 1-2 inches in the CDO watershed, 0.75 inches in here SE Catalina, 1.16 inches at Sutherland Heights, and a whopping 1.92 inches yesterday afternoon and Our Garden (Jesse, personal communication), keepers of the Catalina long term climo records.

What was the effect on the CDO River at the bottom of East WIlds Road?

It got huge. Coulda rafted brown water. Below are more shots of the CDO wash/river again for the second day in a row, ones after yesterday’s dump. A young bystander (i.e., fellow gawker) said I had arrived after the peak! Said the churning waves that developed every 20 min or so due to surges down the wash, were 8-10 feet high! Here they were about half that, 4 feet or so from trough to ridge. I wanted to “shop” a water buffalo in one of these photos so BAD!

Of course, this flood is “mild” compared to the Aug 25th, 2003 flow, which covered Lago del Oro road.

BTW, rainfall totals hereabouts are now up to or exceed the average July monthly amount of 3.xx inches.

The Weather Ahead

With high dewpoints once again today, 64 F here in Catalina, more large thunderstorms are pretty much in the bag, and importantly, this assertion is corroborated by calculating models, all that I looked at. Here is the forecast rain picture for 4 PM today from the Beowulf Cluster at the University of AZ: 4 PM 20120715_WRF Precip (Flash Animation) As you will see, WIDESPREAD rain is expected, with totals in the “best” cores getting up to 1-2 inches again. Wow, three days in a row of major storms.

Things are supposed to dry out some tomorrow, but showers will still be around before a break of a couple or three days.

The End.

Shafted!

Rain shafted, that is. 0.50 inches in 15 minutes yesterday between 2:43 and 2:58 PM. 0.76 inches in 13 minutes in the Sutherland Heights district above Catalina, with wind gusts to 50 mph! One of the most memorable summer days ever here in Catalina. One station, Oracle RIdge in the Catalinas, 1.5 miles N of Rice Peak, reported 2.32 inches. No wonder we had a strong flow in the CDO wash yesterday afternoon! Rafting anyone?

And what a spectacular beginning to the day, filled with portent by those ultra low Stratocumulus and Cumulus cloud bases hugging Samaniego Ridge, the humid air that enveloped us reminding one of the Phillipines, or Gainesville, FL, in July. That was a real key to the kind of day that likely lay ahead, those low cloud bases telling us that our humidity was not just in a shallow layer near the ground as we could feel.

But who needs Florida in July when you can be right here in Arizona? Voluptuous Cumulus congestus clouds piled into the heavens early and often just like in FL, some with pileus veils as well, also common in FL, in route to blossoming into Cumulonimbus calvus, then capillatus clouds, tops reaching above 40,000 feet above us. The Charoleau Gap/Oracle area were hit often all morning and into the early afternoon with great rolls of thunder with one station reporting more than two inches (as noted) and several over an inch.

Because there was so much water in the air, unusually dense rainshafts poured forth from the bottoms of those clouds in just a couple of minutes, oblitering the scenes behind them. Too much precip up there for any updraft to hold off for very long, then the collapse!

Here’s one sequence, the one that led to our 15 minute drenching. The first shot shows the blockbuster that roared down through Charoleau Gap. The ferocious NE winds that preceded the rain caused the clouds to its south (where I was) to experience a growth spurt by displacing the humid air near the ground, jacking it upward. I noticed this happening by the second shot. When the winds hit, you always start looking up for “surprise” developments right over you. But after that, trying to catch a daylight lightning flash from the Charleau Gap storm, forgot to check that darkening base every 12 seconds as I would normally do. My apologies, since the third shot showing the fully collapsed, unbelievably dense rainshaft (3rd shot) was a FULL EIGHT MINUTES later. Damn.

Finally, the last two are during the height of the storm itself. Phenomenal intensity.

I suppose I took too many photos, only about 0.0004% of them can be shown here, but, let us not forget those PRO photographers that had ONE day to document, was it the Chiracaua National Park a couple of years ago? One said he had been conservative and “only” took 2,000 photos, while his friend, more promiscuous, took 8,000 that day! I only took 200 or so…

Here’s a gallery of yesterday’s scenes, including suggestions of a funnel cloud a few miles NNW of Catalina at 10:45 AM. BTW, you can reprise the whole day, as through you were a student standing on top of Atmospheric Sciences Building at the U of A here.

Today

We’re still in Floridian=style air with dewpoints, a measure of how much water is in the air around us, even HIGHER than yesterday with several stations from Yuma to Tucson reporting a whopping 70 F dewpoint. Doesn’t get higher than that here, I don’t think. As pointed out, the higher the humidity, the more precip can form in those Cumulonimbus clouds, but also, that greater amount of water, showing up first at cloud base when it condenses, is also like adding a little furnace at the bottom of our clouds. This is because the condensation of lots of water in the cloud offsets the cooling that occurs as the air expands on its way up. That means its easier for clouds to rise up and dump on the more humid days.

However, along with that, the numbers and clustering of these systems is also dependent on favorable patterns high in the atmosphere, like troughs. If they are not there, and its just moist, you can still get yer Cbs, but they may be short-lived, and in the worst cases, send out huge anvils that help terminate other Cumulus clouds by keeping the surface temperatures down.

So, what kind of a day will it be? Large, long-lived clusters with their inches of rain, or localized thunderblasters that burn out fast?

I don’t know, but Bob (our local premiere scientist on convection), and later Mike, his counterpart at the U of AZ, probably will, our true Arizona summer rain experts…

I haven’t got time to get the forecast right, BUT, the AZ Mod seems to suggests big showers today coming up from the S. So, Catalinians, keep your eye toward Orcacle Road into Tucson by later this morning and throughout the day and evening… Could be another memorable day for us.

The End.

Catalina traces out while flooding occurs nearby again

Flash news: Nearly CONTINUOUS lightning from a localized spot at 3:30 AM just NW of the Tortolita Mountains. Amazing for this time of day. Continuous lightning is a rare event, especially here, mostly seen with big complexes of thunderheads. And this small thunderstorm just erupted at that time “out of the blue”, according to its radar history. Thunder was barely audible, and most of the flashes seemed aloft, toward its top.

Well, quite an exciting way to get started today. What the HECK caused that small cell to explode like that? Now, at 4:08 AM there’s just a sad remnant moving toward PHX. Probably dumped an inch or more on somebody out there at its peak, a real “flashflood” event I’d say for somebody, one that happened before the NWS could even react. Very unusual.

Rehashing yesterday, which produced only a sprinkle here just before 5 PM (trace of rain). Pretty tired of reporting traces all the time. OK, here goes:

Caption function fails again in WP; so here is the caption for #3: 4:31 PM. Row of clouds above fizzles out; none produced a shower (reached high enough for tops to form ice). But, here, a base seems organizing practically right overhead! If this one sprouts a top high enough to glaciate, there could be a real localized dump of rain! Will watch for strands to begin emanating from this base.

Caption 4: 4:47 PM. The awful sight of a broken up cloud base has occurred after the promising solid base. (Many of you know that as a professional photographer, I specialize in photographing cloud bases, its niche I have filled) A few raindrops fell out at this time, suggesting the top may have just crossed the ice-forming threshold height above; but no strands, no shaft developed. Dang.

Caption 5: In the meantime, the dark layer seen in the second photo from a giant complex of Cumulonimbus clouds far to the S has overspread the sky, killing all the remaining Cumulus buildups. This layer, completely composed of ice crystals and snowflakes, would be termed, Altostratus cumulonimbogenitus. Its an awful sight sometimes.

Caption 6: While overspreading the sky during the evening, that layer provided some nice background lighting for this row of Altocumulus castelanus.

This morning’s sky and what we can get out of it:

Well, we STILL have our “stratiform” overcast up top, above at least two other layers of clouds.

The lowest of these was topping Ms. Mt. Sara Lemmon, which are the lowest bases we’ve seen in the current surge.

Going along with that is that the lower air continues to be extremely humid, knocking out the effectiveness of evap coolers, with dewpoints in the mid and upper 60s all across southern and central AZ.

But, one aspect we have to get rid of: the overcast on top of all this. It won’t get hot enough to spawn good storms until we do. But this one is thick and composed of ice. Ice takes longer to evaporate, burn off, unlike Altocumulus droplet clouds, which by definition, are quite thin and burn off readily. These were taken at 5:20, 6:09. and 6:23 AM, respectively.

So, a slow start but one would think, major rains in the area, maybe here, are in the bag. Take a look at the huge amounts that fell to the S of us in the 24 h ending at 5 AM AST this morning, 1-4 inches over a vast area of southern Arizona (from Intellicast.com). The day before yesterday, those kinds of rains were to the N of us.

Our turn today?

In the Dead Zone yesterday; evap coolers to fail again today as more humidity moves in

You can the excessive humidity we have here on this nice map from the U of AZ this morning. Its represented by dewpoint temperatures, the temperature at which the air must be cooled to have condensation. Our dewpoints, up from yesterday are running in the mid-60s; 66 F at TUS and 65 F here in Catalina.

Don’t expect your evap coolers to work too good today, and when they don’t work too good, expect rain. (BTW, I am really great at forecasting rain, very few forecasts I make lack something about rain in them whether it occurs or not-like yesterday.

However, our real summer rain experts, ones that did send out their special e-mails, were quite aware that things weren’t right yesterday. Check this out if you are so inclined. I love to get these since I need to be learned up on summer rain here; still a lotta ignorance going on.

Yesterday WAS shocking in a sense that the many shafts of rain expected expected in THIS area from this computer keyboard did not materialize, only that one off toward Twin Peaks-Avra toward evening, and that nice line of distant Cumulonimbus clouds to the NW (not shown today).

Its amazing that with all that humidity YESTERDAY morning, we ended up being in the Dead Zone. Take a look at this satellite image from the University of Washington at 3:45 PM AST. Look at the clean slot there, marked by the arrow. Dang! Oh, well, TODAY will be different! Expected to get “shafted” (rain shafted) royally around here, at least we should see some, and this time the U of AZ model output is on board, though only has a brief mid-afternoon cell in our area and that’s it for us (this from the 11 PM AST run here). This will be updated later this morning. Gee, with all this humidity, I would expect to see more than that, but don’t feel I am on solid ground due to yesterday’s diappointment.

Here’s the AZ radar-derived map from Intellicast.com showing that 1-2 inches fell just north of us!

Have to go now…will likely blab more later.

8 Notifications

Rainshafts galore

How great was yesterday with the “return of the shafts”! Though we only received a trace here in Catalina, you knew, if you saw them, that some small areas were getting drenched.

How much?

The Pima County Alert Network indicates that 0.28 inches was the most that fell in their gages. But, from experience, you can bet that somewhere up to half an inch fell on somebody out there, judging by shaft density and the height of the cloud bases–bases were a bit on the high side, at around 10,000 feet above the ground (and moderately cool at 5-6 C) . Will post a radar-derived 24 h rain total map when it comes out (it has) from Intellicast.com. (Gee, there it is and that eye-ball assessment seemed pretty accurate.)

Below are some shots of those glorious, local, late breaking, rainshafts. (Was about to give up on rain in mid-afternoon since Cumulus development had stagnated. But as happens, the atmosphere changes, maybe got hot enough with our 103 F at about the time these boys took off, and, voila, up the tops of those Cu went pretty much all around us.

Note the baby rainshaft below. They’re pretty special. If you were to get in one, you would see that it was pouring rain, but only on you. You could look and couple of hundred yards in every direction and see that it was only raining on YOU. You’d feel pretty special about yourself; maybe boost that self-esteem a bit.

If you want the full review of yesterday’s excitement, go here to the U of A time lapse movie. You’ll see the sky change drastically after about 4:30 PM (if you can read the tiny time hack in the lower right hand corner.)

Today?

The amount of water over us continues to climb, and surface dewpoints reflect that, some in the 60s (61 F here in Catalina now)–meaning a lot of water vapor is around, the fuel of a good rainstorm. The local model run from the U of AZ based on 06Z (11 PM LST) data doesn’t have a lot going on hereabouts, it seems to expect today to be a lot like yesterday–but that would be good.

However, with cloud bases likely to be lower and warmer, that will mean bigger dumps in those rainshafts as more water funnels up into those rising afternoon Cumulonimbus turrets. Hoping for a special e-mail later this morning from the U of A summer rain specialists, always exciting since they only issue them when they think something “good” is going to happen. Didn’t get one yesterday, deemed to tame a day maybe. BTW, “good” is defined by meteorologists as heavy rain, blowing dust from outflow winds, flash floods, lightning, maybe some hail thrown in, etc.