About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
A possible great storm has been able to make it through all the model calculations intact for a few model runs now. Spaghetti tell us its in the bag that something big is coming to all of the Southwest around Christmas Day and just after. Check it out:
There it is, laid out for you:
For those who enjoy spaghetti, the above was a real exciting dish to see this morning, one based on last evening’s global data.
Those two people that come here regularly and read these discussions about “Lorenz plots” from the NOAA spaghetti factory, which I have named for the MIT weatherman that first proposed “chaos theory”, Prof. E. N. Lorenz, who noticed that slight changes in initial conditions can make huge difference in stuff later on. That a “butterfly flapping around in Brazil” can affect a storm in Texas kind of exaggerated paradigm. But the idea is correct, if ludicrous in that example, one that seems to recur from time to time.
So, in our weather models today, we alter the initial conditions, at lot more than a butterfly can do, but still slight ones that are reported by our global data network slightly and see what happens to the forecast of the positions and strengths of highs and lows, and where the jet stream will be as the model crunches ahead in time. There might be a couple of dozen trials like this (23?)
In the plot shown way below this harangue, only two of the flow lines around 18,000 feet above sea level are shown from the different forecasts that have arisen from these many model runs. The farther away from the start you get, in general, the more the weather forecasts go to HELL (or do they?)
OK.
Now, where the lines are bunched up is where the model forecast is highly reliable; where they are spread apart a lot indicates cluelessness.
Now if there is an somewhat clearer understanding of this “ball of yarn” plot as one reader put it, you can see with all the bluish lines gathered together in the western US, those that are deep inside the jet stream labeled “552”, that the whole West will be dominated by a gigantic trough or cold air by Thanksgiving Day! Wow.
The red lines, labeled “582”. are on the periphery of the south and warm side of the jet stream. Notice how those lines are “bunched” across the whole Pacific from the troubled fake islands in the South China Sea to Hawaii and eastward into Mexico.
Compare the red lines in the whole Pacific Ocean with the spread in the Atlantic Ocean, the former is indicating more forecast reliability; the latter less.)
It may not seem like it, but these “Lorenz plots” have been a VERY POWERFUL development in forecasting, only recently permitted when computers became so powerful that we could run our models many times in a short time. Weather models require the most powerful computers made in the world, those by China, of course, and not here, which is kind of embarrassing, really1.
All of this is very interesting and indicates a wild Thanksgiving weather weekend! Tell your western friends to watch out!
But, it will be an innervating TG weekend for us cloud and weather-centric folk!
Some rain is indicated in southern AZ due to, hold your breath, the remnants of a tropical storm that filter in Tuesday night and the Wednesday before TG. Aren’t tropical storms supposed to be gone by now? Maybe this is the new climate! Tropical storms all year long!
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Bursting-out-laughing moment just now after the ludicrous sentence above about tropical storms all year…
The above weather discussion was based on the 00 Z model run, which was, tropically-speaking, pretty staid.
But as I was closing out today’s blog, and smiling at that ludicrous statement about “tropical storms all year long”, I looked at the 06 Z model run, just off the press and when I got to the last few panels, I burst out laughing. You might, too.
It has a remnant hurricane coming into Arizona on December 2nd, low center still intact as it passes over Phoenix! This is so funny!
Here are the knee-slapping panels from that 06 z run from IPS MeteorStar for your own amusement. Its REALLY uncanny:
A remnant hurricane hits Baja and comes into Arizona in DECEMBER? Wow. No doubt this is due to that Big Niño down there stirring things up, turning the weather world upside down.
BTW, We seem to miss out on any major rains, however, with the TG situation.
The End
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1Those great big Chineses computers can really hack stuff, too! (Hahaha, just kidding, sort of.)
When some of you were weather browsing this morning, and you saw this forecast map from IPS MeteoStar, valid for next Tuesday, which shows a very late in the season tropical storm off Baja heading toward the Southwest US, while a vigorous winter storm bashes the West Coast, I had a feeling that it reminded you immediately of one of your early weather memories of a similar situation. First, the IPS map.
The map below is from an era when you were a little child and maybe you, too, were clipping weather maps out of the Los Angeles Daily News, if that’s where you lived:
Nice storm we just had. 0.65 inches fell in Sutherland Heights. Would not have predicted that much over these past couple of days to be honest. Total for month now 1.10 inches or a little above the 38 year average of 0.97 inches.
After a long dry spell though at least the next week, November will close out on a dry or wet note, which is pretty encouraging.
Yesterday’s clouds, ice and sun: a soliloquy on ice
Fair amount of ice yesterday in our low clouds. As you would guess on your way to becoming a cloud maven, bases AND tops were especially cold for AZ. Afternoon cloud bases were running about -8° to -9° C, whilst tops were about -15° C. Still ice was not plentiful. How’s come? Well, it seems the amount of ice in clouds is dependent on both the cloud top temperature and the droplet sizes in the coldest parts of the clouds (see Rangno and Hobbs 1994, Quarterly Journal of the Royal1 Meteorological Society) (Hell, no one’s going to read this, though it is now available without having to go through a “pay wall” and the page linked to above has been updated with new pdfs!)
In sum, a cloud with a base of -10° C and a top of -20° C will have LESS ice than a cloud with a base of 0° C with the same cloud top temperature (-20° C) because with a warmer base, the drops near the top of the cloud in second example will be larger.
That seems to be the way it works. So, yesterday’s thin cloud with cold bases had smallish drops, and ice production was a little limited.
Also, if you monitored Ms Lemmon, and the Catalinas in general, you probably were thinking, “Where’s the ice?”, in those cold Stratocumulus clouds as they piled up against them.
Well, when you have strong winds at cloud level as we did yesterday, and with ice crystals taking a little time to appear from some of the droplets that freeze in the cloud stream, grow, and eventually fall out, you’re not going to see much evidence of ice on the windward side of the mountains in these kinds of situations. The ice is going to appear and fallout as snow or virga downwind a good distance downwind, and that’s what was happening yesterday to nearly all of those deeper clouds (with slightly colder tops and larger cloud droplets in them) that formed over the Catalinas.
If you don’t believe me, yesterday’s time lapse movie from the our great weather resource, the University of Arizona, shows this. You’ll see a lot of precip and virga falling of those clouds as they stream eastward from the Catalinas. So, we didn’t get to SEE much ice from those Stratocu clouds but it was there.
Lastly, the sun, as it appeared yesterday at sunset in the dust-haze kicked up by that powerful low that brought us our rains. The jet stream, as was pointed out by a friend, was about 200 mph overhead of TUS at 40 kfeet. Wow.
The End.
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1″Royal”–that is so funny; “hey”, guys, wake up, its the 21st century!
Winter began, meteorological speaking, yesterday with mid-afternoon temperatures in the upper 50s to low 60s with the wind driving the wind chill down to, I don’t know what, something really low . In other words, winter began here in Catalina about 18 h ago.
Enough already! Retired to AZ for warm air and low house prices. Pretty bad, too, out there this morning, with the temp at 44° F right now here in Sutherland Heights; colder yet in low spots of course. Only 36° F now in Black Horse Ranch.
More worse cold expected in about nine-ten days. Precip somewhat doubtful in that a more better cold slam that hits around the 20th1. Pretty strong support in the Lorenz plots (aka, “spaghetti plots”), too, for that cold slam, so get ready. Those crazy plots help us to discern whether a predicted pattern in the model output is an outlier or likely to occur.
In the meantime, going out of chronological order here, THIS coming week end’s lesser cold slam is DRY in Catalina in USA WRF-GFS model run from last evening’s run.
The Canadian GEM, however, based on the SAME global data as the US model, has rain a plenty here in Catalina and all of AZ, Sunday and Monday! The Canadians see a lot of tropical air feeding in from the sub-tropics over much of AZ ahead of the cold front that hits us later Monday, and that’s the reason for all the rain in that model. The US model doesn’t see the moist sub-tropical stream getting much out of Mexico.
Note the large separation between rain in Cal and rain in AZ in the panel below.
So, what’s a weather forecaster to do?
Lean on the Canadians! Their model was ahead of the game on our half-incher rains early in the month compared with the US mod, so they deserve that bit more credibility here, too, I think.
BTW, the two models were identical in not predicting rain in the passage of the cold front yesterday.
The End.
PS: Would post photos of yesterday’s gray, non-precipitating Stratocumulus, lacking ice in it2, of course, for you to review, but in transitioning to a new OS in the past two days, some things have gotten wrecked, don’t work anymore. SOS, as they say.
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1Let’s see if any english teachers are reading this blog….
2Cloud lesson/pop quiz for cloud maven juniors: What cloud top temperature range would you guess for those non-preciping Stratocu. Recall it was a cold day, so you know they were at below freezing temperatures…..
Answer: Guess that tops must have been warmer than -10° C (14° F, in plain speak)!
In fact, the TUS afternoon sounding suggests they were about – 5 ° C (or only 23 ° F), way to warm for natural ice to form, hereabouts, anyway3.
3In really clean conditions, ice does form in clouds with tops as warm as -5° C4.
4These would really be a great factoids to pass along to your neighbors, ones that would enhance your weather esteem in their eyes. Memorization is recommended.
We’ll have to suffer through a few days for the next storm, i. e., experience sunny weather with pleasant temperatures. Its amazing that people all over America come to Tucson to experience sunny days with pleasant temperatures!
0.45 inches total in The Heights of Catalina in this latest round of rain, sounds of rain. Actually, there was also some tiny graupel/soft hail in the rain yesterday, too.
Graupel indicates a lot of cloud droplet water overhead, and that ice crystals were colliding with them until they lost their identity and became little snowballs. In regions where there are very few ice crystals, graupel and the harder version, hail often form. Its likely that nearly all those rain drops that came down with the little baby graupel were melted graupels.
Graupels….. Makes me think of that rock group, Led Graupelin, didn’t have the impact of Led Zepelin. But I have LG’s one and only album entitled, “Compare to Led Zepelin.” Was only $2.99, too! Where’s my guitar? I think I will play, “Stairwell to Heaven” now…
When graupel or hail occur, there’s a pretty good electric charge up there in those Cumulonimbus clouds. Its best to be indoors when its hailing until you know if a strike might occur (if there hasn’t been one already). Besides, its not comfortable being out in hail. And if you were listening to the rain, you heard a few blasts of thunder toward Lemmon around 2 PM that came out of one of the more enthusiastic Cumulonimbus clouds that went by. Got 0.12 inches total to add to the night before’s rain of 0.33 inches.
Then the piston of atmospheric subsidence slammed down to squash our Cumulus cloud tops to levels and temperatures where ice could not form….
Kind of funny to see the Canadian GEM model internally plagiarize itself. Compare last night’s panel at 500 millibars (below) with that same level’s panel foretold for six days from now.
Yep, its the same thing over again in six days, though with less rain IMO:
In another interesting model development, the best USA model, the WRF-GFS is having an internal CONFLICT of major proportions. Check these progs out generated by data only six hours apart. The first one, showing a big trough coming into Cal, was generated by global data taken at 5 PM AST last evening. The panel below it was generated by the same model based on global data taken just six hours later, at 11 PM AST (so it the most recent WRF output available) and has a big ridge along the California coast.
“Which one will the fountain choose?”, to quote old song lyrics1:
Of course, spaghetti tells us which one is right, mostly.
The End
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1Except that here we present only two “coins” not three.
Looks like CMP is low AGAIN on his prediction! Thought a third was the most that could fall in our present storm chapter (10% chance of more, that is), and best estimate, 0.165 inches. Now it looks like met friend and professor at a major university will be much closer with his half an inch prediction. Very painful. Kind of like Stanford with their brainy team beating the Washington Huskies in fubball . It really hurts.
Let us begin today with a look at desert grasses from this summer and falls rains. Pretty deep, knee high in some areas, but as we know here, full of nettles. Kind of a cool look though.
Was heading out to see, what from Google Space, appeared to be a new meteor crater near me, one maybe the astro boys missed. Turned out it was just a house under construction, pretty much underground as well. Kind of a cool thought to build like this, lots of energy saved, which is always good. Cell phone service likely compromised.
…and a dense discussion of detecting ice in them. I am hoping that my followers noted the time of the first appearance of ice in those Cumulus and Stratocumulus clouds that began to fill in during the middle and late afternoon. As that happened, a few raindrops sputtered down here just after 3 PM as that happened. You should have logged both these events, the first visual appearance of ice, and when those drops fell in your weather diaries.
The whole point of this blog is the detection of ice in clouds by layman and laywomen, or “laypersons” I guess it should be now days. This is because if you see ice developing in lower clouds, something will be falling out of them soon. Ice grows in water clouds at below freezing temperatures at the expense of droplets. Therefore, if they stay in a water cloud long enough, they will get heavy enough to fall out. Poor droppies disappear, unless the air is really rising fast.
An interesting side note is that the air FLOWS THROUGH clouds, exiting on the downwind side. A cloud does not just float along as is. It is moving slower than the air, even itty bitty Cumulus clouds the cloudy air is being replaced constantly. The cloud is really moving upwind relative to the air! The POSITION of the cloud moves downwind, but SLOWER than the air that goes into it.
However, if ice crystals form in a small cloud then, they will fall out as single crystals at the downwind edge; they are not going to reach the ground unless you’re on a mountain top. You saw a fair amount of ice exiting the downwind end of clouds yesterday, falling out and evaporating in the dry air there. Where the cloud is wide, then they can gain some mass, collide with droplets, or other crystals and fall to the ground.
You need clusters of crystals locked together, called “aggregates” or ones that have gone through riming, collisions of ice crystals with drops at below freezing temperatures that freeze on the ice crystal making it more massive to get rain drops to the ground. Riming is what leads to graupel (soft hail) and hard hail (the latter to crystals impacting larger, often precipitation-sized drops that freeze on them).
For air travelers, or those who examine tree icing after storms, rime ice is white and produced by small cloud drops; clear icing is caused by much larger drops, usually drizzle or rain drop sizes. If the drops are too small (much less than about 20 microns) they are too small to hit anything and rather go around solid objects. Let’s say you’re on the top of Ms Mt Lemmon, say at 8.000 feet in the fog. The temperature is 24° F. Its windy. You look around and you see no icing on the pine trees trees up.
Where are you?
Ans: at cloud base.
That’s because itty-bitty drops, too small to hit on pine tree needles are flowing around the needles. Some great comments to make that would enhance your stature as a cloud maven junior is to offer your companion the information, “Wow, look at those trees! Here we are ing the freezing fog, and yet they have no ice sticking to them! That means the cloud droplets are pretty small, smaller than about 20 microns! I guess we’re at the base of this cloud system above us.”
These would be really great things for you to say. Of course, as you drove up to Mt. Lemmon, you would know already how far above cloud base you are, but, what the HECK.
You’re at Ms. Mt. Lemmon again, You like it up there when its in the fog. This time the temperature is 25 ° F. Its windy. The pine trees are loaded with rime icing, the ice juts out in the direction from which the wind is coming.
Where are you?
Answer: At LEAST a few hundred feet, more likely a thousand feet or more above cloud base. Drops have reached sizes above 20 microns in size, as they usually do at these heights above cloud base in old Azy. Later, you notice that the clouds are topping Sam (Samaniego) Ridge at the 6500 foot level. Now, they can’t be disconnected layer clouds, but rather SOLID from base to where you are. Drops are tiny again at the bottom of each layer.
Here’s another example. You get up in the morning after a cold winter storm to see “iced trees” on Ms Lemmon. Another comment you could be making is that, “Wow (always begin with “wow”), those clouds must have really been low based last night, way down on Sam Ridge!”
Riming on trees is analogous to the collection of fog droplets by trees and vegetation along the west coasts of the continents in onshore moving banks of Stratus and Stratocumulus clouds that intercept hillsides. These can be significant sources of water. Some studies of droplet collections by trees have found that under the tree, something like 20-40 inches of “rain” can be collected by a tree in northern California.
Wow, I can’t believe all the information I am providing today! Its really incredible.
OK, to first visible ice yesterday, 3 PM:and
The End
Stay tuned until tomorrow evening to find out!
Range of amounts in Catalina, given kind of a marginal moisture situation:
Goose egg to 0.33 inches max, median 0.165 inches, CMP’s best forecast. A friend and met man/prof predicts 0.50 inches here, FYI.
Have felt a little guilty not posting cloud photos from the last storm, Oct 30th, leading my reader into some sadness, maybe even despair the following day when she didn’t see her cloud day reprised. Here are a couple of the characteristic scenes from that day, which includes a shot of a rare drizzling cloud. You will love that shot! Also reprised here is the pioneering technique of novella-sized captions.
Still windy outside, 6:03 AM to be exact. Looks like the observation of windy is going to be correct. Expecting some nice lenticular clouds to show up today. Have cameras ready. No rain before 7:15 PM. Overnight, watch out!
The End
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2.83 inches of rain fell in October in Sutherland Heights, Catalina, Arizona, a little more than twice normal for here (based on Our Garden’s record dating back to 1977). Our Garden is located off Columbus and Stallion here in Catalina, some 2 mi and a bit lower than this site.
The greatest Oct rain at Our Garden or here?
The year was 1983, of course, with 5.61 inches, for perspective. Nearly all of that fell in the first four days!
Will November continue the above normal rainfall here?
Nope1.
The End
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1Wanted to be particularly decisive today. As a matter of fact, women love decisive men, FYI, to spice up the blog with some life knowledge outside of clouds and weather, besides this being a cheap trick to attract more readers of gender.
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Huh? New thought. Advice columns have millions of readers! A cloud blog like this one, 2. Wonder if I could do advice, to help people live better? Oh, here’s one that’s just come in:
“Dear CMP: I want to cut my long hair because I LOVE the convenience of having short hair, but my boyfriend won’t let me. What should I do? Gale.
Dear Gale. Your boyfriend is right. No woman should have short hair. Best of luck, CMP.”
Gosh, that was pretty easy… I think I could do it!
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COntinuing WEATHER discussion….
Sure, we got us Big Niño now, but they don’t have much effect in November unless some TS2 comes up from Mexico way. Niñoes effect more of the later winter and spring, as a rule.
1addendumLong period of “troughiness” is still in the works for the first half of November, but the amplitudes of the troughs will not be great enough to give us much in precip. Remember, gotta have the jet stream in the middle levels (i.e., at 500 millybars pressure, 18 kft or so) over us or south of us this time of the year to get precip. About 95% of our rain in the cool half of the year has to meet that criteria. Therefore, it takes high amplitude trough with the jet stream in the middle levels of the atmo curling around us to bring us rain.
Now wind, we’ll have lots of that from time to time as those troughs go by.
2 “TS”–not in the colloquial sense of the expression, but rather in the tropical sense. Well, I guess if it was a HUGE TS that came up, the colloquial sense might be OK…
This was amazing. I approach one of the puddles on Equestrian Trail. I see that its raining HARD in the puddle. I am only 20 feet from it, but its not raining on my car! Here’s what that scene looked like:
How could this be? Of course, we’ve all seen heavy rain on the road and drove into it. But the illusion here that was so striking is that it only SEEMED to be raining in the puddle, not around it since the drop splashes were not obvious as I drove up to it.
The rest of yesterday was pretty great, too, lots of rainbows, brilliant clouds and skies, too photogenic for a neurotic-compulsive photographer. However, one of 221 photos was of a human, a neighbor, not of clouds and rain shafts.
Here are a few too many cloud photos; excess is kind of a specialty of mine:
Still a lot of “troughy” weather ahead, and chance for decent November rains in the first half of the month after cold one goes by, followed by a short dry spell.
The End.
A dollop of rain is on the doorstep, the 29th-30th, but what is intriguing to this cloud maven person is not the EASY forecast of a trough in a few days with some rain, but rather passing along the fun and excitement of “troughy” flow overhead of the SW US in the longer forecast range, between in 9-20 or so days from now, a period so FAR in advance that few dare to go there.
Of course, if the air is “troughy” aloft, our chances of rain are up, though not guaranteed.
What WOULD be guaranteed by troughy air over us is a lot of middle and or high clouds like Altocumulus, Altostratus, and Cirrus, kind of like we had yesterday during that upcoming 9-20 day or so period. And with those clouds, if that’s all we get is clouds, comes great sunrises and sunsets from time to time.
So, CMP is predicting at least some nice sunrises and/or sunsets in the period of 9-20 days from now1.
And of course, ANY credibility for such a profound forecast so FAR in advance with such specificity borders on the unprofessional and shouldn’t really be done, but 1) by examining the NOAA spaghetti factory output, say from last night we can get a tiny bit of credibility, and 2) we don’t worry about professionalism here. If you want really great professionalism, see Bob’s forecasts.
and here:
See red lines and how they bulge southward just off the southern regions of the West Coast and Baja.
I hope you’re happy now.
As you will also likely conclude from these plots, it looks very Niñoish due to the bunching of the red lines in the southern latitudes, those associated, in this case, with the southern branch of the “SJS” or, “sub-tropical jet stream. Remember how important “bunching” is on these plots! Bunching is a measure of confidence on these plots.
Recall, too, that Jacob “Jack” Bjerknes and Pyke (1960s) first hypothesized from the 1957-58 Niño event that it had caused a strengthening of the southern region of the jet stream; made storms stronger, farther south in the eastern Pac which is what happened that winter and spring. We expect some of that strengthening of the southern portions of the jet stream this year due to the HUGE Niño now in progress. I think I will make some toast now.
That strengthening is because the temperature gradient from Equatorial regions to mid-latitudes is greater during Niñoes, as you would guess. Extra warm air is rising up in the eastern Pac where lines and groups of deep Cumulonimbus clouds are forming, transporting heat and moisture upward in regions where they usually don’t exist without a big Niño with extra warm ocean water.
The End.
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1Remember our motto: “Right or wrong, you heard it here first!” Forecaster: “Alive and local”, too.