Rain dump truck; 0.73 inches

As per my photographic niche, I began to capture some promising bottoms of clouds yesterday afternoon around 2 PM.  The first shot shows a promising cloud (so-so sized Cumulus congestus) drifting westward over Mt. Sara Lemmon.  The next shots show the progression in the appearance of the bottom (my specialty) before the dump truck was emptied.  Nice!  Its always satisfying to document the bottoms of clouds BEFORE the dump truck is unloaded.  Before it was over, visibility was momentarily less than 50 yards in swirling winds and blinding rain.  Unbelievable moment.  According to our tipping bucket gage, rain rates got up 8.4 inches per hour at that peak moment.  (The record, Btw, is over 12 inches actually recorded in less than an hour in Missouri!).  A few minutes after the last photo is when the rain started.

Well, it was a great rain, and the desert veggies seemed to respond to this one event by propping themselves up overnight and looking noticeably greener.

Thunder-rooskie

With a thunderstorm at 7 AM LST yesterday mainly toward Saddlebrooke, you may have thought, “What a thundery day this will be!  It will be like Cherrapunji during the Indian-Bangladesh monsoon season when it rains and thunders all day and inches of rain pile up!”

And of course, it wasn’t going to be like that at all, rather it was the famous deceptive weather “play” called, “thunder-rooskie”, whose first derivative was executed in a Nebraska in a fubball game in which the ball was not hiked by the Big Red offensive team, but was left on the turf for some lineman to pick up while all of the other players were too busy pushing each other around to notice the “egg” just lying there.   (Actually, the name of that trick play was “fumble-rooskie”, as students of the game will know.)  At least here in Catalina, we did get measurable rain in the morning, pretty refreshing, too, of 0.04 inches.  Lots more toward SB.

So wha-happened?  First, that mostly stratiform overcast helped keep temperatures down; only 91 F in Catalina yesterday.  100 F have sent volcanic explosions of Cumulonimbus clouds into the sky, but, except in a few isolated areas and on the White Mountains, that didn’t really happen.  Too damn cool.

Also, when you have a disturbance strong enough to produce rain and the rare morning thunderstorm, more often than not it is replaced during the daytime by dryer air asscoiated with an attendant couplet of descending air motion, and a little of that happened yesterday, too.  So, rain and thunder at dawn are often associated with disappointing afternoons here in Cat Land.  Naturally, I hoped for more, seeing those low cloud bases topping Samaniego Ridge, even during the afternoon.  But other than an occasional, and very brief tower, they did not even make it to the height where ice forms and rain falls out.

Here’s the rest of our muggy, but dry day:

 

Drops away!

As a photographer, you like to develop a niche.  My niche, of course, if you follow this site, is gray matter overhead, an amorphous, gray balls.  Now yesterday was a great day for adding something to my collection since a Cumulus base, one that was clearly headed for better things than just being a Cumlus cloud, developed almost straight overhead, giving me a great chance for another “signature shot.”  See below.  I don’t know of any other photographer that specializes in this kind of shot; kind of sad, really.

Once again, you’ll have to click on the image to get a proper size, and hold your monitor over your head.  People seem to enjoy doing this.  Make sure your plugs and connections to the monitor are long enough to do this maneuver.  Sometimes I forget to tell people this, and then they get mad when an external hard drive falls on the floor when performing this maneuver and it won’t work anymore.  Sorry.

Of course, I monitored this base and kept shooting ( you never know which one will be the best) it, and then, there came the strands of the first drops out the bottom, that fabulous moment so few photographers catch because it is VERY subtle.  Next photo, if you can detect it!

OK, this is probably too hard for you to see much in the second shot, though I can see something.

How about a bit later, when its obvious?

Pretty cool, huh?

I was really hoping for those giant drops, but the initial shaft was just a hair to the east, and so while it rained HARD, the main load was dumped toward Sutherland Wash to the east.  But, we did get 0.16 inches here. See next photos

What were seeing in this emergence of a fall streak is the overhead transition from a Cumulus congestus to a Cumulonimbus calvus to Cb capillatus.  Eventually only the “hair”, that is, the fibrous ice cloud is left up there.  The whole bottom two thirds of the cloud has rained out.  Since there were so many Cumulus clouds that went through this transition yesterday, we were left with a huge amount of what would be called, probably should stretch your tongue before trying to say this so you don’t injure it, “Altostratus cumulonimbogenitus.”  Here’s the great sunset shot showing mostly that mass of ice cloud up there (underlit by the ray of sun).  Enjoy once again!

 

 

 

 


 

Everywhere but here

What a great cloud day yesterday was with thunder on the Catalina Mountains by 10 AM. It seemed so promising for a major rain here in Catalina. But no, shafts to the left, shafts to the right. In fact, we were “surrounded” on three sides by shafts at times, but only residuals of those shafts got here to produce a measly 0.04 inches!  Still, it was nice to see those cloudbursts out there drenching something.

Here are a few photos of yesterday’s clouds, beginning with a 9:44 AM morning shot, once SO FILLED WITH PORTENT.  I remember how happy I was!  Look, the bases of the Cumulus clouds are touching the top of Table Mountain!  Think how warm they must be, maybe 12 F (50 F)!  And we remember that the WARMER the cloud base, the more easily they rain!  Also note ice falling out of the right side of the top of this cloud in the first photo.  Imagine, at 9:44 AM, those towers were already able to ascend to the level where its cold enough for ice to form, and you know what that means, RAIN falls out! Yay!

Below, is an example of that assertion about rain and ice.  First, a cloud (cumulus congestus) whose top has already reached that level where ice forms–look how different it appears in that highest sprout in the middle of the photo, how smooth it looks compared to the crenellated, cauliflowery look in the turrets below.  But there is NO rain falling out yet.  That conversion to ice has just happened.  The much higher concentrations of cloud droplets are being replaced by much lower concentrations of ice particles, and that’s why you can visually detect this change in appearance.  The lower concentrations of ice make the cloud look a bit less detailed in top structure.

While that highest portion is already converting to ice, you still see no shaft. This is a great moment to impress your friends with some razzle dazzle conversational meteorology:  “Hey, guys, that cloud is gonna have a helluva shaft of rain in just a coupla minutes!”  It would be a magical moment for you.

How long will it be before you see a rain shaft?  Only about two minutes! And here, in that first shaft shown in the next photo two minutes later,  are where the largest rain drops and sometimes hail will be found. You don’t want to go over the speed limit, but under this type of cloud BEFORE the shaft is out the bottom is where you should be to see some real rain excitement, that is, rain bouncing about 6 inches off the pavement, but you’ll have to pull over, maybe some close lightning strikes, too.

Finally, a typical afternoon shot of the rain shafts around Catalina, in this instance, looking toward Twin Peaks.

Man, that was a fun day yesterday for cloud viewing!

The End.

Promising fizzle

 

If you looked outside to the south and upwind of Catalina later yesterday afternoon, after a disappointing day of Cumulus development over the Cat Mountains, you saw this behemoth of a top protrude out of a mass of cirriform clouds beyond Pusch Ridge.   Excitement begins.  Can it hold up long enough to reach us?  This complex of thunderstorms that trudged slowly toward us was around Green Valley at this time (4:29 PM).  It faded almost from the moment this photo was taken.  Go here to see the radar imagery of this from IPS Meteorstar.  Alas, all we got from it was sunset color by the time it got here 3 h later.   The colorful underlit bubbles of downward moving air are called “mammatus” if you care.

We continue to be on the edge of the main summer rain areas to the south, and so we will be lucky to get anything again today other than sunrise and sunset color today. “Dang”, as a friend would say.

 

Sprouts, and not much more

Here they are, reflecting the heat island of Mt. Lemmon yesterday, repeated narrow surges of heat and cloud sprouting upward, and only one reaching the level where ice formed, and a little snow fell out–second photo.  Go here to the U of A fubball-practicing Wildcats Atmospheric website to see the whole interesting sequences of pulses yesterday.

Note frizzy stuff at left and below residual cloud patch in the second photo.  That’s ice that formed because the top of the cloud reached temperatures well below freezing, and is a good example of the threshold level at which ice formed yesterday because there is only a small amount coming out of this cloud.   Had that top ascended another couple of thousand feet, it is likely that it would have been all frizzy and fibrous; completely ice.

The height at which cloud tops begin to form substantial ice tends to change day to day and much of that due to how warm the bottoms of the clouds are.  The warmer the bottoms of the clouds, the higher the temperature at which ice first forms in clouds!  The highest temperature at which ice has been observed to form in any cloud is around -4 C (25 F), and then only when the cloud has formed rain already by an all liquid process called coalescence where cloud droplets merge to form bigger droplets, and eventually those colliding-merging drops reach sizes where they qualify as drizzle or rain drops.    Here in Arizona, clouds occasionally form ice in clouds with tops  warmer than -10 C, but mostly they have to be below -10 C.  It happens, too, but it is rare that clouds here form rain by the collision-coalescence process.

It may seem odd that ice does not form in clouds when they get colder than 0 C (32 F), but rather at lower temperatures, sometimes much lower.  This is a mystery that is still being investigated to this day.

When did we find out the complexity of ice formation in clouds, to continue a bit of a lecture?

We really found this out in Project Whitetop, a large, sophisticated and randomized cloud seeding experiment in Missouri carried out in the early 1960s under the aegis of the University of Chicago.   When researchers went up in aircraft to examine clouds on not seeded days,  they they found that the Cumulus clouds already had some ice in them in cloud tops that had never been colder than -10 C.  This was quite a surprise since nobody really thought ice formed much in all clouds until the tops were at least around -20 C (-4 F).  This was because measurements on the ground of artificial clouds in cloud chambers chilled to -20 C were almost always ice free until that temperature.  Nature’s trick?

We had a hint of a nice sun pillar, faint vertical column, at sunset, here for something more accessible.

 

The End.

 

 

 

 

11 (hundredths)

While we would have liked to have had our rain amplifier turned up to more than 11, as Nigel Tufnel might say, but we got this amount out of an unusual situation in which you often miss rain.  The cloud that did it formed virtually overhead and rained itself out without moving.  Best dump of the day was a bit S of this place toward Cat State Park.  But… let us not get greedy.   Our summer vegetation is looking stressed, and so yesterday’s odd situation of virtually no movement of rain/thunderstorm cells meant that a cloud had to build right over us to get any rain.  And that’s what happened when we got almost all of our 0.11 inches yesterday.  The first shot, looking straight up just before it began, with these eyes detecting some evidence of ice in the top of the cloud overhead and getting excited, since that would mean there would be a rainshaft soon.  In these kinds of overhead shots, as I have mentioned before, you will have to raise the monitor over your head to really get this first photo correctly.  Maybe count to 10 or 12 so it counts as some form of exercise.  Would be good for you, that’s for sure.

Went outside at this time to wait for the first drops, hoping I would see those silver dollar-sized ones that fall out first through the updraft1.   It took a few minutes, and I did not see those giants.  Still, the drops were big enough and numerous enough to produce 0.07 inches in about 5 minutes.  Nice.

With no wind “up top”, it was a bit odd to see that this cloud that had rained itself out, still virtually overhead 40 min later as a patch of Cirrus (spissatus cumulonimbogenitus) if you want something to choke on so early in the morning.  See the very upper left hand corner of the second shot:

In the meantime, Cumulus werer lining up and boiling upward just S of us, and eventually went on to produce much heavier rains on the west side of the Cat mountains and into Oro Valley.  Also nice.

Here’s that sequence to the S, beginning with a promising line of Cumulus bases:

 

 

 

 

Interesting, perhaps, historical note below, he sez, re raindrops

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1Mr. Cloud Maven person has the undistinguished, perhaps embarrassing note of sharing with his lead professor, the late Peter V. Hobbs,  the Guinness world record for measured raindrop size (see below).  So, Mr. Cloud Maven person knows something about where those giants (about 1 cm in diameter) fall out.  BTW, a bigger drop was recorded by researchers in Hawaii (Prof. Ken Beard, personal communication) AFTER some global publicity about our record went out.  But, Dr. Professor Ken Beard, did not publish his drop.  So, does a tree fall in the forest if you haven’t published anything about it?  I don’t think so.

BTW2, it was thought via experiments and theory, still prevalent in most textbooks, that rain drops larger than about 5 mm in diameter could not exist, so the finding of drops perhaps as large as a cm in diameter (10 mm, or close to half an inch) as we reported (Hobbs and Rangno, 2004:  Super-Large Raindrops, Geophys. Res. Letts.) was controversial.  I guess the clouds don’t read the textbooks.

Trace King; how to be one

Had a trace of rain yesterday, August 5th, in Catalina as a few drops fell just after 5 PM, and again just after 8 PM.  If you weren’t outside or driving in the neighborhood, you wouldn’t have noticed.

I always felt recording a trace of rain was important, but the recording of traces is definitely human influenced: there are outstanding trace “reporters”, and those who aren’t so diligent.  An example, discovered while looking at rainfall data for my hometown Los Angeles.   For decades it seemed, Sam Miller, was the Weather Bureau (now NWS) “statistician” reporting to the newspapers the amount of rain or other climate data of interest from the Los Angeles official climate site, downtown.  Sam NEVER missed a trace, whether it was a summertime sprinkle (sparse larger drops that fall rapidly) from mid-level clouds, or drizzle (fine, close together drops that almost float in the air) from low, maritime Stratus clouds prevalent in mornings in the Los Angeles basin during the spring and early summer.  During Sam Miller’s regime, Los Angeles averaged about 20-25 traces a year.   When Sam passed in the mid-1960s, he was replaced by an observer that was not so vigilant.   The number of traces fell to just several a year!

At the time, being a little naive, I thought I had discovered an air pollution effect.  It had been reported that smoke from cane fires in Australia had reduced rainfall from relatively shallow clouds.  I thought maybe that the notorious Los Angeles smog had reached a level where it had turned off the Stratus drizzle machine (mid-level clouds would not be affected).  I got excited, but it wasn’t long before reason set in and the “heterogeneity” in the data was found to be due to human influence.

Even today, I take pride in detecting “traces” of rain, recalling Sam Miller.  A “trace” tells you, when you see it in the climate data, that rain was in the area.  And especially here in the summertime, perhaps even heavy rain that missed gauges.  So, while hoping for a “dump” from a promising cloud base almost directly overhead (first pic) I waited outside for many minutes so I could “detect” it first hand.  A heavy shaft of rain was already drenching the west slopes of Samaniego Ridge.

I waited outside for the first sparse fall of giant drops the size of silver dollars, those big boys that fall through the updraft overhead first before the collapse and main rainshaft falls out.  Didn’t happen.  The shaft from the cloud base overhead developed that bit too late and all we got is a few, spares medium drops, more or less having been blown our way by the wind as the main shaft that eventually came down.  Oh, well.

Evidence of those drops having fallen, in nearly 100 F temperatures, was soon gone.  If I hadn’t been outside watching as this base developed overhead, I might have missed it, or at least when it fell.  However, I do have a “trace detector”, our oldest car which is parked outside.  That car is always aquiring a new layer of dust, and, at the same time, I clean the windows every day.  With the inevitable dust, overnight “traces” of rain are NEVER missed!  I deem myself therefore, the “Trace King.”  I’ve noticed that many people do not park their cars outside for the purpose of detecting traces of rain, and so that’s why I EASILY surpass others trace reporting because so many night events are missed.  Its great to be at the top, I have to say, to be good at something anyway, if nothing else.  An example of the detection of a trace from an overnight event below (2nd photo)  Note small mud balls where drops and mud congealed.  What a great sight!  Got me another “trace” for the records!

I hope now that many of you will now appreciate the meteorological importance of parking your car outside, 24/7, refreshing its surfaces each day for that new, possible trace, to help you be that bit better weather observer you always wanted to be.  Soon, you could be the “Trace King” of your domain!

The End

In case you missed it…

yesterday’s lightning criss-crossed rainbows over Catalina/Oro Valley.  Couldn’t capture the lightning, but two strokes occurred while this glorious rainbow was in progress.  Once again, being from Seattle, I have to say, “Never seen that combination before.”  I now really wish the University of Washington had had a branch campus in the Tucson area–go Huskies!   The first shot was taken at 5:49 AM, about the same time as the rainbow fragment in an earlier post.  You can see that the other part of yesterday’s rainbow is in EXACTLY the same position as that colored highlight shown back then.  It was odd, too, that there still was lightning with this very weakly, raining, and dissipating Cumulonimbus, and in particular, a cloud-to-ground strike.  Seemed to continue the regime of unusually electrified clouds in the past 24 h, ones that seemed ordinary, or even weak, yet produced prodigious amounts of lightning, and continued to flash long after they seemed “dead” as clouds.  That is, no new updraft areas apparent, just virga and weak rainshafts as shown here).    Hmmmmm…..

Nice, unexpected thunderstorm this morning with an extremely close strike here about 3 AM.  Total rain only 0.07 inches, but with an interruption of the summer rains predicted for several days, the mods say, any rain is welcomed!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sunny, with rain and close lightning strikes

Good grief, what a last 12 h or so.  First, the smallest thunderstorm that produced the most vicious cloud-to-ground strikes that I’ve experienced developed overhead just before 5 PM LST yesterday.   Took the photos below looking in several directions because, as the heavy rain fell for a few minutes and the lightning bolts were striking all around the house, it was SUNNY!   Somebody musta got a good rainbow shot!  Take a look;  the following photos were taken amid close, cloud-to-ground strikes and pouring rain (amounting to 0.13 inches in a few minutes):

Here’s the cloud what done it, just as the “festivities” got under way.  Truly amazing!

 

 

 

 

 

 

 

 

We all know small (Cumulonimbus clouds) can produce very small shafts of rain, but it was how highly “electrified” this small cloud was that made it special.  And that phenomenon continued into last night as that huge complex moved in from the SE after 10 PM last night with about as much lightning as I have seen over such a wide area.  Its still producing lightning to the NW-N.  Sadly, we only received another 0.01 inches overnight to bring the 24 h total to 0.14 inches.  But somebody got a pounding overnight.  Let’s check with our friendly ALERT gage reports.  Not much around here or on the CDO watershed, darn!  Still hoping for a Sutherland and CDO wash run before summer is out.  Last year they were running on July 30th.   These dogs were pretty happy about it back then, too; here a scene from the Sutherland wash last year.  But, I nostalgiate.   (What a great sight that is, water running in our washes!)

 

Most of yesterday’s appears to have been to the S and SW of us.  Oh, well.  As Scarlet said, “Tomorrow is another day”, except that now its “today is another day.”  Mods tending to dry us out in the days ahead.  Drat.

The End.