0.22 inches was, indeed. how much rain fell in the form of drops from Nimbostratus clouds yesterday as a modest little rain band generated by a rapidly moving trough swept through during the afternoon. Regional precip values can be found here. Our local area got the most, up to about a quarter of an inch, as often happens in marginal storms.
Yesterday’s storm marked the beginning of the new, more normal weather regime for southern Arizona, as has been blabbed about here in recent weeks. No more week after week of droughty weather with temperature far above normal, the kind of weather that has marked this whole fall and winter so far! I. e., “Thank you very much, a snowbird might say, but get the hell out!”, the rest of us might conjure up, thinking about the needs of our desert’s wildlife and vegetation.
Indications are now that below normal temperatures and above normal precip are ahead for us and all of Arizona in late Jan and early February.
The evidence for these claims?
Below, the stunning, jaw-dropping evidence for this seemingly outlandish assertion in the form of an ensemble (spaghetti) plot generated by NOAA last night. I have followed these charts for almost ten years now, and I cannot remember when such a strong signal (clustering of flow lines) 15 days out has occurred before in our region.
So, excessively excited this morning when I saw it! Its been annotated with excitement text.
This troughy pattern begins to take place on January 30th. Until then, a strong but dry cold front with a lot of wind comes by in a few days, on the 25-26th.
The whole interesting, if excessively gray story is shown below:
The weather way ahead
The title sums up where we are now. Will we go have more rain? Oh, yeah. But not right away, as you already know.
I use that expression not only to draw attention to myself since my name is Art, or, “Artie boy” to mom, but also because I had a role in bringing this phenomenon to the attention of the scientific community; that is, that an aircraft could glaciate portions of clouds at temperatures as high as -8°C. This in a peer-reviewed article so controversial it was rejected twice by journal reviewers before “getting in “(pdf here)! Some background on why this happened is found in a footer way down below….
Its common knowledge today that an aircraft can produce in essence a contrail in clouds at temperatures down to about -10°C and must be avoided when researchers are sampling the same cloud over and over at below freezing temperatures.
Back to the beginning:
The day began well enough with a nice sunrise over the Catalinas:
Here’s the early morning National Weather Service balloon sounding from the U of AZ:
Then, as the Altocumulus layer filled in from the west, the aircraft effects roared to life. An example from yesterday, one that passed right overhead of little Catalina!
The weather ahead
More interesting middle and high clouds, probably a great sunset/sunrise or three, but no rain, just virga. The present mass of middle clouds passing over has some virga and sprinkles, but that’s about it from this episode. No real support yet for a change in our dry, warmer than normal weather regime in spaghetti plots though one trough a week or so out is forecast to bring a little rain.
Some background on “APIPs”
This phenomenon had been shot by photographers for decades, yep, DECADES, BUT, it was believed (apparently) by those doing cloud research, that it only happened at very low temperatures such as those when the normal contrails we see occur (at temperatures lower than -35°C), viz., it was ignored.
Another factor was that all of the rare photos of this phenomenon, dubbed “Aircraft Produced Ice Particles” (APIPs, by yours truly, though not the greatest name) appeared in lay or quasi-lay publications and were likely missed by those with big Ph. Ds. who only read technical journals. An example of this was on the cover of the Bulletin of the American Meteorological Society in 1968, a cover shot which drew the greatest amount of reader comments that the journal had ever seen! They went on for a couple of months, some suggesting that the ice and hole in cloud was due to a meteorite!
Also, it was a rare case indeed when the photographer could report the temperature at which it occurred.
I was thinking how great yesterday was for you. Started out with a spectacular sunrise (lasted just a couple of minutes), and then you could watch for pretty much the WHOLE day, orographically-formed Altocumulus opacus and castellanus transition to ice crystal clouds (in this case, Altostratus with virga and some mammatus) right before your eyes!
After sunrise….this odd scene below of an extended Altocu lenticular cloud:
Hope you saw them and recorded them in your cloud and weather diary. I’m thinking that at the next Cloud Maven Junior meeting we should devote a lot of time to this issue. It was a rare day yesterday that the WHOLE day had that phenomenon occurring as aircraft penetrated those clouds, usually on ascent or descent. Sharp descents/ascents produce holes. See the sequence below if you don’t believe me (ppt from a recent talk):
Yesterday’s clouds: lots and lots of aircraft-produced ice
(btw, see note below about pop-up ads in this blog, ones that started to appear after downloading latest WP software)
——————About those nuisance ads—————
Note to me and the two other people that drop by my cloud or “clod” blogulations: The embedded pop-up ads are due to a WP third party plug-in that needs to be repaired. It will likely happen today.
After consultations about ads…
Oddly, those pop-ups and blue highlighting and double underlining do not seem to be present outside of my personal view of my own blog, this according to hoster, “godaddy.” Even using a different browser other than FIrefox does not show them as I have just verified.
As here, just to reinforce that assertion a bit. Its a link to a recent blog by my cloud-obsessed friend and author, Maria Mudd Ruth. I strongly recommend buying a few of her books. Really, I do!
But in viewing our deep blue skies, pocked with little fluffy Cumulus clouds over the past two or three days, you would not need convincing that even tiny clouds are beguiling, a wonderful attribute for a planet to have. Having mountains on a planet is great, too, and watching the interplay of clouds and their shadows on them is a never ending pleasure. We’re pretty lucky when you think about it to be on a planet like this one. Hope you think so, too.
No rain ahead, glumly, though some sprinkles are out there this morning as frontal cloud band passes over. Just a little too high off the ground for real rain. And the cloud tops aren’t quite cold enough to form much ice, too. Those cloud tops get colder going to the NE, and so higher terrain up thataway (e.g., Show Low) are getting some light rain this morning. Right now, there’s a little sprinkle just beyond Romero Canyon, so we got a little ice this morning in them clouds.
What was interesting is that I never saw no ice yesterday, to continue the slang of rock and roll, in another cheap attempt to reach out to another demographic. The clouds were just a bit too warm for ice-formation, tops running in the -4°C to -5°C range according to yesterday afternoon’s Banner University of Arizona’s balloon sounding. Some may have bulged up to nearly -10°C, but still not quite there. I looked constantly for signs of ice and never saw none, and neither did you, of course.
Bases were cool, at about 4°C, at 11, 000 feet above sea level, or 8,000 feet above Catalina. Tops, about 15,000 feet above sea level. So, they were running around 3,000-4,000 feet thick with no ice. This was a situation where dropping dry ice into those clouds would have created snowfall, then sprinkles, that would not have fallen naturally. Doubtful anything would have reached the ground anywhere near our elevation, however, but up at Ms. Mt. Lemmon, something would have likely even measured from doing that far enough upwind.
In summary, yes, there are some fairly rare times you can get some precip out of clouds by seeding them and yesterday was one of them1.
Today the clouds are thicker, drop sizes therefore larger in those tops of a cloud band similar to the one we had yesterday evening. As drop sizes increase, the temperature at which they freeze also increases. Well, at least that’s what we found over and over again at the U of Washington.
The result, some ice has formed even though they’re hardly colder than just -9°C or -10°C (14°F). Check the radar:
Here are some cloud shots from the past couple of days. Should be some more great scenes today:
Due to time constraints, we now move ahead in the action. Well, its not really “action” is it?
Well, not that much, just a day ahead….
Moving ahead to yesterday and the day long cloud band….
The orangy colors denote the strongest winds in “Jetty Jetstream”, and as you know, the colder, low clouds, ones capable of reaching the temperatures where ice forms, are contained within that ring of strongest winds at this level (500 mb). So, while the models I have looked at so far have no rain here, I think there’s a pretty good chance of a rogue shower tomorrow morning anyway. At least there should be some nice Stratocumulus/Cumulus tomorrow and some will have ice in them. As you know, it’ll be awful windy today, too, maybe 40 mph or so in brief gusts here in The Heights of Sutherland.
Also will be looking for some nice lenticulars since “Jetty” will be right over us, but a little toward the warm side where lenticulars mostly occur.
In the meantime, spaghetti suggests a big trough in our area again about nine days from now. The later ACTUAL model outputs don’t show much of anything. What’s up with that? I’m hanging with spaghetti that later model runs will indicate a strong trough, and at LEAST another pulse of cooler air, and another minor chance of rain as we are going to see today and especially tomorrow as when become within the “ring of winds” aloft. Didn’t Johnny Cash sing something about that? Maybe it was Wall of Voodoo…
Below, some spaghetti for you showing a big trough over Arizona and the Great Basin which is not much reflected in the actual models, as noted. But, just watch my friend, how those model outputs will change to reflect a bigger trough about this time!
Doesn’t look promising for much rain here in Catalina in March, however. No rain in sight through the next 10 days at least.
Let’s check our 7 inches with what’s happening upwind, say, in CALIFORNIA, and see if there’s been any drought relief there, through February, via the CNRFC:
As you are likely to know from many media stories last year, Cal was in a drought siege of five straight years, with but got a little relief last year in the northern part thanks to help from the giant Niño, one of the strongest ever.
Alas, it was one that failed to deliver as the big rain producer for the south half of Cal and the SW in general as was expected.
In case you’ve forgotten how bad things were in Cal, let us look back at what was being said, those horrific appearing drought maps, and also how hopeful were were at the time that the Big Niño would take a bit bite out of drought. This is a really good article:
Then, when the Big Niño faded away like maple syrup on a stack of buckwheat pancakes last spring and summer, we were surely doomed for more dry years. And, for a time, the dreaded cold tongue of water in the eastern equatorial region, the so-called, La Niña, started to develop, which would be no help at all for a good rain season like a Big Niño is, usually.
The Niña faded away, too, to nothing as the winter went on, so we really didn’t have much going on in the tropical Pacific to help us figure out what kind of winter rainfall regime we were going to have om 2016-17. Not having anything going on meant winter rainfall could go either way, a difficult to figure out situation for season forecasters.
In retrospect it is pretty astounding how big a signal must have been out there SOMEWHERE that this winter was going to be one for the history books on the West Coast in general, and in particular, for Californians. Californians saw their drought chewed up and spit out in a single winter, including snow packs so high the height of some mountain peaks have been revised. (I’m kidding.)
No one saw such an astounding winter coming.
This winter sure makes one think of the QBO (Quasi-biennenial Oscillation, one up there in the Stratosphere where there’s almost no air (haha, well, practically none)… Did the QBO have a role in this astounding winter; was there a delay in the effects of the Big Niño even without a bunch of convection in the eastern Pac tropics? Doesn’t seem that could be right…
But, William “Bill” Lau, U of Maryland scientist, reported some statistical evidence of such a lag way back in ’88 due to a QBO connection of some kind and ENSO, no physical cause could be discerned, however, not yet, anyway. Lau, 1988, is reprised below for readers who want to go deep:
As the morning wore on, the Altocumulus deck faded away, moving east, and we were left with some Cirrus clouds, but what kind?
Well, that was it for photography yesterday.
Doesn’t seem to be any reliable indication of rain in sight. Oh, sure, rain here pops up in the models almost every day, but its about 12-15 days out. As the model gets closer to the day it predicted rain, it seems to go away like the “water mirage” on a hot paved road; always ahead of you, but you never get to it. We’ve had some major rains indicated in the models as of a few days ago, but spaghetti was never very high on those events (clustering those crazy lines in a trough over us), so it wasn’t even worth mentioning.
Not much else to talk about, no rain of course; what is that?
But with so many colorful scenes yesterday, we can be partially sated by the lives we lead here sans rain here. October ended with a puny 0.01 inches in Sutherland Heights.
Now, because I grew up in California and remain a little Cal-centric, this brief diversion from AZ:
But droughty Cal got nailed though, from about San Luis Obispo, so we can be happy about that I guess. One station, Gasquet RS, near the Duck border, got just under 28 inches in October; stations in the Santa Cruz Mountains, way down by Monterrey, got between 14-17 inches! From the California-Nevada River Forecast Center, this nice map of October rainfall anomalies in that domain. Red is real dry, and that’s the color we would be in if it was the California-Nevada-Arizona River Forecast Center:
But let us not dwell any more of generous rains that others got, but celebrate the color and clouds of Arizona. Here are yesterday’s glorious scenes, beginning with a spectacular Altocumulus lenticularis under some Cirrus at dawn:
Now, just some nice lighting and color:
In a further celebration of dryness here, let us examine the rainfall cumulative rainfall predictions calculated by the University of Arizona’s Dept Hydro and Atmos Sci computer the period ending at Midnight on November 5th. Says the coming rain in the State misses us here in SE AZ while falling just about everywhere else, of course. Dang. Let’s hope it one of the worst model predictions ever!
Truly LATE breaking news, untimely really, but Augustober 18th was too special a day to ignore:
Giant clouds, dense rain shafts, frequent lightning in the area throughout the afternoon, dewpoints in the high 50s to 60 F; can it really be after the middle of October? Or, is this some kind of preview of climate change we can look forward to in the decades ahead, that is, if you’re thunderphilic?
1:56 PM. Anvil of the Cumulonimbus over west Tucson, drifts overhead of Catalina, and in three minutes, rain drops started to hit the ground. This is amazing because those drops had to fall from at around 20, 000 feet above the ground (estimated as bottom height of this thick anvil) and could only have happened if those isolated drops had been hailstones ejected out the anvil, something that also only occurs with severe storms with very strong updrafts in them. So, if you saw those few drops fall between 2 and 2:05 PM you saw something pretty special.
The weather just ahead, and this might be it for precip for the rest of October
A nice-looking upper level trough is ejecting over us from the SW this morning but the computer model says its going to be a dry event. A second low center forms just about over us in the next day. AZ model doesn’t see much rain for us throughout these events, and rain doesn’t begin here until after dark today.
I think that is WRONG; bad model. Watch for some light showers this morning, then a break and rain overnight (which the models do predict). Due this quite bad model forecast, as seen from this keyboard, I feel must interject for the blog reader I have, an improved rain prediction for Catalina over that rendered by a computer model.
Feel like guesstimating a minimum of 0.25 inches between now and Thursday evening, max possible, 0.60 inches, so the median of those two, and maybe the best guestimate being the average of those two, or 0.425 inches here in Catalina. When you see a prediction of a rainfall total down to thousandths of an inch, you really know that the person predicting it knows what he is doing…..
Below, your U of AZ disappointing, but objective, take on the amount of rain based on last evening’s data and one that is the result of billions of calculations. One must remember that cloud maven person’s calculation of the rainfall amount for Catalina is only based on three.
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