The weather WAY ahead (10 days or more) – Page 13

Pretty cloud day yesterday; storms dead ahead and ahead

In case you missed the pretty sights of yesterday:

7:05 AM. Sunrise on the Altocumulus. Two layers are evident.

8:42 AM. Kind of blasé except for the rarely-seen-in-AZ (faint) halo. Altocumulus with Cirrostratus above.

3:30 PM. Pretty patterns; Altocumulus perlucidus.

4:45 PM. Cirrus uncinus and Altocumulus (clouds with shading). — 4:45 PM. Cirrus fibratus (not hooked or tufted at top) and Altocumulus (droplet clouds at right with darker shading). Lower gray portions beyond Pusch Ridge and extending to the horizon is probably best termed Altostratus.

4:56 PM. Nice lighting effects on Samaniego Ridge. — 4:56 PM. Nice lighting on Samaniego Ridge.

5:21 PM. Your sunset. Nice underlit virga from patchy ice clouds. Could be termed Cirrus spissatus or Altostratus, if you care. — 5:21 PM. Your sunset. Nice underlit virga (light snow fallout, likely single ice crystals, not flakes) from patchy ice clouds. Could be termed Cirrus spissatus or Altostratus, if you care. What kind of crystals, you ask or didn’t? Bullet rosettes.

The clouds and weather just ahead

Expect more Altocumulus, Cirrus, and Altostratus today, patchy and gorgeous. Would expect some nice Ac castellanus (one with spires) as an upper level low off Baja starts to move toward us. Some measurable rain likely tomorrow in the area, but probably barely measurable, maybe a tenth at most since it will fall from middle clouds with a lot of dry air underneath them. (Enviro Can mod still sees rain around here tomorrow.)

Middle clouds might get large enough to call the (small) Cumulonimbus clouds, with a slight chance of lightning tomorrow, Thursday, as this low moves up and over us.

So both today and tomorrow will have some great clouds!

WAY ahead; watch out!

After a quiescent period of gorgeous, misleading days, where the temperatures gradually recover to normal values and you’re gloating over the nice weather you’re experiencing by coming to Arizona from Michigan, blammo, the whole thing caves in with strong storms and very cold air heading this way. Yesterday’s 18 Z WRF-GOOFUS model run for 500 millibars (rendered by IPS MeteoStar), was, if you like HEAVY precipitation throughout Arizona, well, truly”orgasmic.” You just cannot have a better map at 500 mb for Arizona than this one from that run. That low center over California, should this verify, would be filled with extremely cold air from the ground on up, cold enough that snow in Catalina would be expected as it goes by. So, there’s even a prospect of a white Christmas holiday season. Imagine.

Valid 264 h from 11 AM AST yesterday morning, or for 11 AM AST, Saturday, beginning of football bowl season I think, which last until February I think. — Valid 264 h from 11 AM AST yesterday morning, or for 11 AM AST, Saturday, beginning of football bowl season, which last until February I think.

Now will this verify exactly like this? Nope, not a chance. But, spaghetti tells us we’re going to be in the Trough Bowl, filled with cold air and passing storms beginning in 8-10 days from now. How much precip and how cold exactly it gets is unknown because these progs will flop around in positioning the troughs that head our way. There will be major troughs passing through, so while the amount of precip is questionable, the cold air intrusion is not. It was just so neat, exciting, mind-blowing to see that such a gargantuan storm has been put on the table for us in that 18 Z run.

Most likely subsequent model runs will take this exact map away, but then put something like it back, until we get much closer to verification day, the 21st. May even shift around on which day is the doozy, too, by a couple of days either side. Still, a really exciting period of weather is ahead.

This may seem odd, but one of the keys to our storms way ahead is the eruption of a huge storm in the western Pacific (and that storm is shown developing in the last day (144 h panel) of the Enviro Can mod.

———–dense reading below————-

That erupting, giant low pressure center will shoot gigantic amounts of warm air from the tropical ocean far to the north ahead of it in the central Pacific. That warm air shooting north, in turn, causes a bugle to the north in the jet stream, a ridge, which deflects the jet toward the north toward the Arctic. As the jet stream does that, there is almost an immediate response downstream from the ridge; the jet stream begins to turn to the south, developing a bigger an bigger bulge, or trough to the south. So, a jet stream running on a straight west to east path across the Pacific can be totally discombobulated when a giant storm at the surface arises and shoots heat in the form of clouds and warm air northward¹. In this case, all of this takes place beginning in the Pacific in about 6 days, so that a sudden southward bulge, a buckling of the jet stream, due to that giant low in the western Pacific 8, 000 miles away, happens over the western US. And voila, our big cold and maybe our big storms, too. then.

————end of lead-filled text———

The End.

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¹First noted by much-honored meteorologist, Jerome Namias, who did not have the Ph. D. but was great anyway, in the early 1950s.

“Oh, what a beautiful morning”; and day its going to be

1) I like to refer to songs about weather, though the musical references I’ve used are somewhat dated, as here, a song from 19th Century I think. BTW, tapping on the link above, you’ll see a guy riding a horse AND singing at the same time because he’s so happy, so it really fits the big western life we’re all leading here in old Arizony in the wintertime and seemed apropos. I wouldn’t recommend singing AND riding at the same time, however, unless you know you’re horse reel good. Might get spooked if it was you or me singing and not the cowboy, Gordy MacRae¹.

BTW#2, if you watch that entire song link above, you’ll see whole crowds of people getting carried away with the State of OK at the end of it. But…you’ll also notice in that scene that there is a MOUNTAIN on the distant horizon in the background. I don’t think they were in Oklahoma for that song! So, maybe they didn’t really like Oklahoma as much as they claim in song…. Now, where was I?

Man, the clouds are going to be spectacular today, zipping along like a dragster on nitro! Expecting some real great lenticular clouds, those hover ones, downstream of the Cat Mountains, too. Lots of wind, as well, to add to the drama with a Big _Cold Front (B_CF) getting closer during the day, then passing us during the evening-overnight with some rain by morning. Likely to be a 10-20 degree F drop in temperature within an hour or less, as this real “bad boy” cold front and wind shift go by. Ely, NV saw a 56 degree drop in temperatures in 24h. We Need more rain; always. Cold? Not so sure about that. All in all, a “beautiful” day² coming up.

How much rain here in old Catalina?

We’re on the edge of the jet stream up there, and you know what that means, on the edge of the precip, too. So, if you’re telling your friends how much rain you expect, and as a CMJ, they will expect you to comment on it, you’d best not go overboard and say, “a half an inch between tonight and Friday morning”; play it down some.

On the plus side, this is a storm type (flow pattern type, more westerly up there) that we Catalinans get MORE rain than surrounding areas, other than the mountains. So, on the edge means a low rain prediction; but the flow pattern suggests pushing a little on the greatest amount possible for an edge storm. Here’s the range I would tell you to say to neighbors:

Bottom (since it might miss), 0.08 inches (the “8” for faux accuracy); top, 0.50 inches (yep, has a high potential due to the storm type; that is, the angle of the winds impinging overhead on our mountains). Average of these guesses, which likely is the more accurate guess-amount, 0.26 inches.

Later we will compare the U of AZ supermicro Beowulf Cluster model prediction, one that takes our best model’s overall prediction for Arizona, the one WRF-GFS, and then breaks it down into our local areas better, like here and on the Catalina Mountains, because it uses much more detailed terrain. (Not available yet here at 4:45 AM–to Hell with it then!) ((Still not available as of 6:24 AM. It is finished..publishing now.))

There’s another cold blast on the heels of this one. Hits on the 8th. Poor TUS marathoners… ‘Nuf said.

The weather way ahead

2) With the upcoming storm and cold well in hand, that is, well described by our excited met men and women, both at the NWS and on TEEVEE, where in the latter case they make a LOT of money, really, its incredible how much (well, maybe not in TUS, but LA? Oh, my) Let’s see, where was I? Oh, yeah, I thought I would look WAY ahead, two weeks, which in weather model terms is like an astrologer looking through a telescope at the giant star, Betelgeus, its that far away in model prediction terms.

Still, I REALLY think you need to see this forecast even though its so far away because its pretty giant, too, in weather terms. If you’re too lazy to click on “this”, I have gifted you with the highlights below, highlights that might be the best forecast maps I have ever seen (again). Yes, to quote the song, “Everything’s (weather-wise) going my way.” ( “My way”? To Catalina, Arizona.)

Drum roll……

Well, there they are. I hope you’re happy now. Its quite an orgasmic sequence from a weather standpoint.

Why? There’s about THIRTY-SIX hours of rain in our area are foretold from these maps, 14-15 days from now! That last one has heavy rain throughout Arizona! BTW, I’ve posted them in sizes that are proportional to their credibility, thumbnails.

Now, since I’ve been learning you up on spaghetti, I’ll let you decide whether its a Big_Outlier (BfO). Take a look here and at where the”blue” lines are. They would have to be clustering down around Rocky Point-Puerto Penasco for this forecast to have any serious credibility.

Yesterday’s clouds

Cirrus ones. As always with our deep blue skies now days, so pretty up there. A few shots:

8:01 AM. The ever-present, rarely seen Cirrus castellanus (bubble Cirrus). — 8:01 AM. The ever-present, rarely seen Cirrus castellanus (bubble Cirrus lower center).

8:02 AM. Cirrus fibratus (long, more or less straight trails, at least from this overhead view).

5:26 PM. Subtle color in Cirrus and distant Altostratus layer (deep ice cloud). — 5:26 PM. Subtle sunset color in Cirrus and in a distant Altostratus layer (deep ice cloud).

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¹Not wearing a helmut, either, which is also a bad example besides singing while riding a horse.

²Words can mean different things to different people, and here, “beautiful”, as in the title, may not be the “beautiful” day you were expecting to be described.

Airplanes slice through clouds; leave icy canals and trails

WHAT a gorgeous day was yesterday! Perfect. No wonder the northlanders come here in their droves now! Its great to see (via the increasingly larger number of out-of-state license plates) all the people that want to be where I am already!

While waiting for the storms and cold air just ahead now, this cloud commentary:

Along with the pretty high and middle clouds was a rarely seen phenomenon, aircraft flying into those “supercooled” Altocumulus droplet clouds were converting them to ice in their wakes. These are similar to contrails, called by me, APIPs, Aircraft Produced Ice Particles. That’s right, your Catalina Cloud Maven person named that phenomenon, though its not a great name since it could apply to usual contrails as well. Modest brain strained hard, but couldn’t come up with anything better. So, given that background, he’s probably going to make a big deal out them when he sees one or two here.

Its rare because the Altocumulus have to be pretty cold, -15 C (5 F) or so and colder¹, and at a level where aircraft are flying, usually in a descent or climb pattern to their normal flight altitudes up around the higher Cirrus levels (30-40 kft above sea level and at temperature generally below -35 C). Typically because of climbing or descending, the ice canals, or holes with icy centers, are short and small. Here are a few examples from yesterday, but you really want to look at the U of AZ timelapse movie to see a bunch of them going by in those pretty Altocumulus clouds and mackerel skies we had. Note that as cold as these Altocumulus clouds were, they were not producing ice:

12:21 PM. Ice strip produced earlier by an aircraft that flew through supercooled Altocumulus clouds. Usually these events lead to optical displays like this sun dog almost overhead. You have about 10 seconds to see it, but of course, Mr. Cloud Maven person was waiting for it to happen. — 12:21 PM. Ice strip produced earlier by an aircraft that flew through supercooled Altocumulus clouds. Usually these events lead to optical displays like this faint sun dog almost overhead. You have about 10 seconds to see it, but, of course, Mr. Cloud Maven person, on a hike with friends, was waiting for it to happen.

11:50 AM. Note Cirrus-ee part upper right.

And there were other fine sights! Look at this display of Altocumulus perlucidus undulatus, rippled mackerel sky:

1:19 PM during hike with friends, not just people standing there, in case you thought someone who would write like this and take cloud pictures all day might be a recluse and have no real friends. Shown are Bill and Vollie, George and JoAnn, who are admiring the Cirrostratus shield coming over the horizon. — 1:19 PM during hike with friends, not just people standing there as I walked by, in case you thought someone who would write like this and take cloud pictures all day might be a recluse and have no real friends. Shown are Bill and George, JoAnn and Vollie, admiring the Cirrostratus shield coming over the horizon. (I do see why you might think that, though.)

4:42 PM. Day ended up with a great big halo; haloes are pretty rare here in the kinds of Cirrus clouds we get. More Altocumulus out there, too.

Weathering ahead….

Looks like cold spell will last, once underway, into the middle of the month. SNOW indicated HERE in Catalina-land on the morning of December 11th from a crazy model run based on last evening’s global obs at 5 PM AST yesterday. Here’s what that morning looks like overhead, at 500 millibars:

Valid at 5 AM AST December 11th. Thinking about making snowballs that morning. Also, in appeal to youthful readers, I have texted some here. Astonishingly deep cold air piles into Arizona, Those northlanders will be piling into their jeeps and heading home. Unfortunately, an examination of the reliability via the newly named, “Lorenz plots” from NOAA, show virtually no support for this “solution.” It appears, at least for the moment, dang, as a crazy outlier, likely due to some goofy error (s) WAY upstream somewhere. But, its fun to contemplate snowballs here in Catalina.

BTW, the local weather services all around the SW are already worked up over the coming cold wave and have issued Special Statements, quite fun to read because they reflect the excitement we weather folk are feeling now as we look ahead to wind some rain, and a big frontal passage followed by cold air. After all, the weather’s pretty dull here in SE AZy most days of the year, and by “dull” I mean that not much is happening except for pretty clouds and nice temperatures, a weatherperson’s “dull.”

The End.

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1 Yesterday afternoon’s Tucson balloon sounding which I forgot to look at until now:

Rawinsonde balloon sounding data from Tucson. Balloon launched around 3:30 PM local, rises at about 1,000 feet a minute. — Rawinsonde balloon sounding data from Tucson. Balloon launched around 3:30 PM local yesterday; rises at about 1,000 feet a minute.

Severe weather pattern ahead for West and central US

Summary statement: Begins in 5-6 days in the northern US, then expands southward; goes on and on, like the discussion below, after that. Cloud pics WAY below the “novella” on spag plots.

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Our docile weather in the West for the past few months is about to end, as well as for those in the Rockies and Plains States. Wasn’t gonna blog on TG day, but looking at mods, and realized that I am the SAME person that I was as a 6-year old in Reseda, California, on January 10, 1949, that ran up and down Nestle Avenue knocking on doors to tell people it was starting to snow that afternoon (!), I realized that same “gotta tell ya” impulse lives on.

The trigger for THIS “gotta tell ya” is how bad the cold, snow, rain, and wind look for the western half of the US starting in about 5-6 days from now as cold air and storminess works its way south from the Pacific Northwest and Rockies at that time. I am sure you have heard something about this developing pattern already from your favorite media weathercaster, but I’ll try to take it a bit farther out in time, and tell you why I think you can do that in this case.

I haven’t looked at the models per se with the exception of the Enviro Can one, one in which the lasted posted output is at the start of this episode, but rather the excitement for Mr. cloud maven person was triggered by those chaotic looking, “errorful” plots we call spaghetti plots, “Lorenz plots”, if you will, posted by NOAA that tell us how sensitive a pattern is to small errors.

It seemed, too, like there was something to be learned from them, as well demonstrating a high confidence pattern of a severe weather pattern more than a week away. Many forecaster, maybe most, shy away from forecasts beyond a week because we know how often they are faulty. But there are exceptions and this is one coming up.

ann dec 4 5 pm spag_f192_nhbg — Valid at 5 PM AST, December 5th. This map shows a high confidence of a mammoth, cold trough at 500 millibars covering most of the US. Its “ginormous” as a friend used to say. You really don’t see anything like it, that is, like that black “quiet” zone extending so far south anywhere in the whole northern hemisphere!

OK, here we go.

Above I have added boxes in this plot to show you where the forecast is highly reliable and in another one, where its not. This is indicated by the bunching of those lines, height contours, the same ones, from many model runs starting with the introduction of slight errors. At first in these plots, with errors being tiny, there is no difference in them in the first day or two. But, as time goes on, the errors have greater impact. A metaphor: when you hit a ball off the tee, the error in the first inch of travel is nil in magnitude. But 5 seconds later? Oh my.

Here, the bunching of lines in most of the US is what got me going. Continuing the metaphor above, after 5 seconds and 300 yards of travel in this case, its analogous to 2 yards from the hole! In other words, the were essentially no effect of errors in the model runs; you slugged that golf ball perfectly.

But what does it mean, in terms of weather? That trough (the curved area where the “high confidence zone” is located, means a tremendous plunge of cold air into the West and Plains States. Don’t need to look at future maps to know this. You all know that a trough is a tongue, a wedge, of DEEP cold air that drags cold air at the surface southward on the west half of it, and drags warm air northward on the east side (in this case, toward the eastern US. The size of this wedge indicates a gigantic area of high pressure from the Arctic will be pushing DEEP into the West and Plains States as this pattern develops in the few days before December 5th.

Once established this pattern lasts for several days, a huge, deep and cold trough dominating weather throughout the US. And where the air masses clash at the ground presents ripe conditions for low centers to spin up, given a trigger aloft, like a traveling, much smaller wave in the jet stream where the lines are bunched.

Below, farther along in the sequence, these plots each one day later than the one above that illustrate how a confident pattern begins to erode. In this case, “uncertainty” in the central and eastern Pacific begins to spread eastward into our confident pattern; the blue lines start to go goofy (highlighted by boxes):

Last, here is the plot for 15 days (360 h) out in which those little errors have had their biggest effect, really done a number (haha) on the forecast confidence game, everything’s pretty unreliable except maybe in eastern Asia and the extreme western Pacific, and along the East Coast.

But, even with all of this chaos below, we can see that the model still thinks a trough (a bend in the contours to the south) will still be present in the mid and western sections of the US. Since we know that weather, once changing into a new pattern likes to stay in that pattern for weeks at a time (with brief interruptions), a reasonable forecast for December would be colder than normal in the Southwest and West overall, and in the central US, while its warmer than normal in the East, particularly the southeast US.

Precip? Always more dicey than temperatures, but CM is going with above normal in the interior of the West and in the Southwest, near normal to above normal here in SE AZ. Remember while reading this, Mr. Cloud Maven person is NOT an expert in long range forecasting, like for a month, and, he likes to see precipitation in the desert, and those wildflowers that follow. (“Truth-in-packaging” clause.)

In a couple of days, the Big Boys at the CPC, that is, the NOAA Climate Prediction Center, will be issuing their temperature and precip forecasts for December. It will be interesting to see what they make of these patterns, combined with other factors like sea surface temperature anomalies and northern hemisphere snow cover.

BTW, with a pattern like the one coming up, snow that falls during the storms is going to remain on the ground for long periods due to the lower than normal temperatures, those that snow cover helps to maintain (strong feedback loop, as we would say).

Your clouds of yesterday

If anyone is still with me, you had your Altostratus, your Altocumulus, and some Cirrus. Here they are:

8:31 AM. Altostratus, an ice cloud consisting of single crystals and snowflakes. Slight falls of snow (virga) can be seen at the bottom, that rumpled look. WAY too high above the ground to reach it, estimating 18 kft here.

3:41 PM. Altocumulus perlucidus (left), opacus center and right where they get solid. These clouds are comprised soley of liquid droplets; no virga is showing for one thing, and the greater detail, sharper edges goes with a droplet cloud composition. Droplets are almost always in far higher concentrations that are ice particles in clouds, thus, they have sharper edges.

5:22 PM. Pretty nice sunset, Altocumulus overhead left; in the distance Altocumulus floccus with heavy, funnel-looking virga fall, and extreme distance, some following Altocumulus castellanus, no virga yet.

5:24 PM. Close up of prior scene. Last row visible on the horizon is a nice little row of Ac castellanus.

Uh-oh

“Call the uh oh squad¹.” I wasn’t going to blog today, was going to take a few hours off, enjoy the TG week by cleaning up the place all day before guests arrive tomorrow afternoon, not really enjoying anything at all, really, but rather, having gone into a new mental frame of mind, a higher one, in which you notice things that you didn’t notice before that are now “wrong”: the clutter, the dirt, the shabby windows, the dog hair. You now see them all!

But then when I saw the newest spaghetti plot, heart started pounding, not just because I love spaghetti, real spaghetti and these plots, but also because of what I saw in the new plot: The “old outlaw”, that old prog, the “old outlier” of yore, the one I showed yesterday with its severe storms for AZ and Catalina, and then went on and on about it likely being an “outlier” model run, and really, exerting a LOT of mental energy to try to explain why those severe storms were UNLIKELY to happen here in southern Arizona.

But that forecast of strong storms is, in fact, becoming the mode in the model! Outlier a la mode; a weather dessert of sorts for us in precip-challenged old Arizony.

Compare these plots below carefully for the SAME verification time, the first, the very one I showed yesterday, and the second, hot off the NOAA spaghetti site from last night:

Valid for the same time as the plot above, but generated 24 hours later. I think you see what I mean by "uh-oh." — Valid for the SAME time as the first plot above, but generated 24 hours later.
I think you’ll see what I mean by, “uh-oh.”

What’s so different?

That trough in the mid-Pacific is now foretold to be much deeper (extends farther to the south; compare), a key for our own much deeper, more southward-penetrating trough downstream here in the West. Those blue lines (that cold 552 height contour at 500 mb) are now bunched farther south in the new spaghetti plot for both locations, in mid-Pac, and in the West, with many fewer of them to the north (open, blackish regions).

Not much jet stream amplitude (north and south meanderings) upstream?

Probably not much downstream, either. Look, too, at how the yellow lines have amplified here between the two plots! So a firming up of high amplitude upstream translates to a better chance of troughs extruding southward into old AZ downstream.

But why did things change?

After all, NOAA puts in tiny errors at the outset of model runs to help show us what the most likely outcomes are, so we don’t expect to see “outliers” start to dominate progs as they have started to do since two days ago. But they have. Dunno for sure why things changed, but one would guess some real errors out there must have been large, larger than the ones NOAA starts with to see how the model runs change (disperse) from the one they put online for us to see.

Valid at 5 PM AST, December 5th. That contour at 500 millybars represents the cold interior border of the jet stream with really cold air there, aloft and at the ground. The jet core at this level is far south of us at this time. Is it raining here? If you have followed this blog your answer, without even needing to look at the precip forecast, is, "oh, yeah, baby", probably lots of it, too. — Valid at 5 PM AST, December 5th. That contour at 500 millybars (about 18,000 feet above sea level) represents the border of the cold interior of the jet stream with really cold air there, aloft and at the ground. The jet core at this level (brown area) is far south of us at this time. Is it raining here? If you have followed this blog your answer, without even needing to look at the precip forecast, is, “Oh, yeah, baby”; probably lots of it, too. I got so excited I misspelled, “Ensanada”! (Let’s see if anyone notices…..) Maybe its a test to see if ANYONE is reading…since I misspelled it twice!

In case you don’t believe me, that is, what I wrote in the caption above about it raining a lot here just judging by the 500 mb configuration, I now present the precip forecast for this period, one I had not seen before writing this sentence, and show it to you.

Rain areas for the 12 h ending in the early morning of December 6th (5AM AST)

Actually, rain begins (in this mod series from IPS Meteo) during the day of December 3rd, as the storm that threatened rain at the close of November, first of December, FINALLY dribbles in from the Pac.

So, this could be quite the weather period for Arizona coming up. Certainly enough cold air and severe storminess is making its way down the coast from AK and points north, that we should be hearing about severe weather, snows in unusual places, blizzards, that kind of thing, before this system gets here. Looks like we’ll have plenty of warning, too, to prepare for an “interesting” spell of weather, hard freezes following the storms, windy periods, maybe another inch of rain over a few days, that kind of thing.

Great pattern for the flowers of spring!

Of course, that far out, its not in the bag for significant rain, but cold air, a hard freeze late in the first week and beyond? That seems to be the MOST confident outcome.

Today? You got yer Altostratus, nice sunrise, just now, and those clouds, thinning to Cirrus, likely augmented by Altocumulus, will likely be here all day–check sat loop here from the Huskies. Enough holes in this cloud sheet, though for a great sunset I think.

The End.

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¹ But who out there would remember that single, and Robert Ellis Orall?? But I have it!

Strong early December storms indicated for Arizona in yesterday’s model run, now 24 h old

It doesn’t get better than this if you like wind, rain, snow, piles of it, and newspaper stories about Southwest storms. From IPS MeteoStar, these renderings for December 6-8th from our BEST model, the WRF-GFS, crunched from yesterday morning’s global data taken at 5 AM AST:

2013112512_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_276 — Valid for Friday, December 6th at 5 PM AST. The colored regions where the model has calculated that precipitation will fall during the prior 12 h before this. Precip indicated in just about all of Arizona

2013112512_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_288 — Valid at 5 AM, Saturday, December 7th. Twelve more hours of precip throughout most of Arizona!

2013112512_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_300 — Valid at 5 PM, Saturday, December 7th, precip center moves to just about over my house/Catalina and environs again as it has so many times in the past.

2013112512_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_312 — Valid for 5 AM, Sunday, December 8th. Rain area intensifies and grows in size over SE Arizona! I was beside myself with joy when I saw this model output!

Now, after all this excitement, you may wonder why, with several model outputs since yesterday morning at 12 Z (5 AM AST) the writer has not updated these maps. If you have followed this site for any time at all, you know the answer; the subsequent model outputs were not as good. In fact, the last one, from yesterday evening’s 5 PM AST global data, had NO PRECIPITATION at all south of about Winslow. Such an outrageous, even if possibly more accurate model output due to being based later global data, is NOT going to be displayed here! I want you to be uplifted by thoughts of coming storms and rain, spring wildflowers in profusion, not droughty thoughts.

But we have a conundrum: Will it or won’t it rain here in Catallina in the first week in December?

And, of course, you know what happens here. We examine that ball of yarn, those “Lorenz plots”, namely, the spaghetti plots from the NOAA spaghetti factory that puts them out, those plots you’ve come to love, to see if we can tease out the answer to our conundrum; which model run was the outlier, the one likely to be WRONG!

Let us first look at the projected contour map for 500 mb, about 18,000 feet above sea level, or about half way through the entire mass of the atmosphere, which is kind of scary when you think about how low that is:

Valid at 5 PM AST, December 7th. We will compare the 552 height line with those "errorful" ones on the Lorenz-ball of yarn plots. — Valid at 5 PM AST, December 7th. We will compare the 552 height line with those “errorful¹” ones on the Lorenz-ball of yarn plots below, and see if a lot of those same height lines show up SOUTH of Tucson, as it does here in this great prog. Fingers crossed…. We need a LOT of those same contours south of us for this NOT to be an outlier, goofy model output.

Here it is:

Valid at 5 PM, December 7th, during height of predicted strong AZ storms shown above. The light blue lines are the errorful, key 552 contour lines. Look, there’s only ONE south of Tucson, very unlike the stormy model output showed above! Most of those bluish 552s are WAY to north, indicating that the stormy Tucson mod run was an outlier, not likely to happen as shown.

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¹“Errorful”–if you can imagine it, our government weather service puts little errors in the global measurements that were actually taken, and then runs their computer models over and over again with slightly different combinations of DELIBERATE errors. They do this because we cannot measure the atmosphere accurately over the whole globe at the same instant. There are always measurement errors, but we don’t know what they are.

The stronger a pattern is, the less it is changed in the future even with those tiny errors having been introduced at the beginning of the model run. The more fragile a pattern is, the more chaotic the future prediction of it gets. This means that where patterns are strong, the red and bluish lines are bunched together, and where the model is clueless, the lines are all over the place.

Naturally, in the first few days of a model run, pretty much all of the lines are bunched together, but after awhile, the fragile patterns start to emerge as the lines go crazy. Here in the western US, the plot above indicates, even though its 10 days out, that there is, without doubt, going to be a strong trough, lots of stormy action in the western US. The blue and red lines are RELATIVELY bunched together.

The thing that’s missing for us, is the AMPLITUDE of the pattern, that well-predicted trough with storms in the West does not appear like its going to reach down to Tucson, but rather produce rain and snow in the northern third of the State. On the other hand, its not so far away that further slight changes won’t result in precip here, though not the behemoths indicated in the progs at the start of this blog, which I think was yesterday sometime.

In the cool half of the year, its essential for the core of the jet stream to be over or south of us for rain to get here, and that core is located between the red and blue lines above, so its not so far away. Fingers crossed…

Finally, The End (of the footnote, and everything else)

Fog and Cumulus; Mr. Frosty ahead?

An unusual sight yesterday: bulging dawn Cumulus fronted by fog. These Cumulus (not spawned by ground currents) suggest instability aloft, a rapid decline in temperatures with increasing height, which allows the buoyancy of “warmish air” in-cloud surrounded by cooler air to go up, whilst fog¹ suggests the opposite; cold, damp, heavy air that can’t go anywhere but down, slip sliding away as it did yesterday because its topped by warmer air, a atmospheric “glass ceiling”. Ground fog like this is colder air that you can see.

DSCN6509 — 7:21 AM. Looking NW from Equestrian Trail Road across Oro Valley.

DSCN6504 — 7:19 AM. Odd multiple layers of ground fog (lowest) and Stratus clouds (“clouds” because they’re not on the ground) with shreds of Cumulus fractus above Samaniego Ridge.

DSCN6501 — 7:07 AM. As above, suggesting a very fine layering of moist air with little temperature caps.

Here in Catalinaland, this kind of layering of cold air, as most of you know, is endemic on clear nights. Those who drive down across the CDO wash from Sutherland Heights or along Lago del Oro from the surrounding higher terrain know. Because of the stupefying amounts of rain in the past three days, the air is damp enough at ground level to form fog and you can see whose colder at night than you are IF you are above it. Also, anyone who walks their dog in the morning passed innocuous looking gullies, is aware of how cold air flows downhill and collects in low places.

The lack of density of this fog indicated that it formed in real clean air, air that didn’t have a lot of junk in it (which would also contain a lot of CCN, cloud condensation nuclei. Pretty hard to get fogs like we had in Bakersfield, CA.

Once things warmed up some, and with Arctic like air up top, Cumulus arose, a couple of which sprouted icy tops and shafts, namely, became small Cumulonimbus clouds, tops around 20-25 kft. Along with these clouds, there was a treasure of sunny highlights and shadows moving across the Catalinas. Here you go:

10:49 AM. Small Cumulus humilis begin forming as temperature warms up to 50 F (egad). — 10:49 AM. Small Cumulus humilis, mediocris begin forming as temperature “warms up” to 50 F (egad).

11:13 AM. There's water on them rocks! Not enough to get water into the CDO locally, but the Sutherland Wash developed a trickle. Just too much dry ground up there for much runoff. — 11:13 AM. There’s water (glinting) on them rocks! One of the prettiest sights we get to see on the Catalinas after some rain. Not enough water was dumped on the mountains during our drought-denting storm to get water into the CDO Wash locally, but the Sutherland Wash developed a trickle. Just too much dry ground up there for much runoff with the relatively steady rains that we had.

12:10 PM. Small Cumulonimbus clouds erupt just north of Saddlebrooke. Thought I heard thunder from this complex later.

2:50 PM. While small Cbs developed to the north, the Cat Mountains were only able to produce Cumulus congestus (“heavy Cu”). Didn’t see any ice; neither did you, or there’s something wrong. But, if you go here (U of AZ time lapse), you WILL see some forming in the downstream portions of clouds over the Catalinas. Sometimes not seeing ice is because the tops are blowing off away from you before they show it, especially when there isn’t a lot.

DSCN6602 — 3:48 PM. Last gasp Cu congestus. Will highest turret form ice?

DSCN6603 — 3:49 PM. Ice starting to show!

DSCN6606 — 3:53 PM. Droplet cloud completely gone. No question now, nice ice plume. You want to target aircraft into densest portions of this ghostly veil of ice; will correlate with densest portions of liquid cloud. Not enough ice for a shaft below the cloud, but someone felt a few drops below it!

Below, one of the attributes of our partly cloudy days and low near-winter sun angle; pretty lighting:

The weather way ahead, first week in December.

Pile of cold air to drive into West Coast and Rockies during the first week in December. Snow even possible here, the air is that cold, but mainly the cold air will likely lead to the first cold spell where temps drop significantly below freezing. The worst days look like the 5th and 6th right now, after the threat of rain and or snow pass. So, if you have an evap cooler, you’ll definitely want to have it drained before then if you haven’t already taken care of it (like me).

Rain threat at the end of the month/first day or so in December is fading some in mods, but I refuse to give up on it!

The End.

=============

¹Fog is “gof” spelled backwards, BTW. Has a lot of meanings and I avoided the obvious juvenile approach (today), “Think I’ll go goffing today” which I wouldn’t say anyway because I don’t play gof.

Rain, and more of it

AZ Map of USGS gauges here (takes a couple of minutes to load); USGS AZ amounts here.

Pima County ALERT gauges here (Mt. Lemmon already at 0.67 inches at this hour!)

Rainlog.org here (best if used after 7 AM AST).

CoCoRahs here (best if used after 7 AM AST)

NWS rain totals here.

AZ agmet rain totals here.

I’m trying to keep you busy today. Maybe you’re retired and you don’t know what to do with yourself. Well, today you can look at building precipitation totals in Arizona all day! It will give you something to talk about.

In fact, occupying retirees with searches for precip data is why we have so many different sites that record precipitation. We have a lot of retirees in AZ, low temperature refugees, and we need to keep them occupied and out of trouble.

Imagine how awful it would be if we had ALL of these rainfall amounts in ONE place and you could look at them all immediately, or have a map plot of all these sites and amounts? Imagine just CoCoRahs and Rainlog.org being friends and cooperating together and just having one site for their rainfall collections? It would be like the Berlin Wall coming down, precipitationally speaking. Oh, well, that’s not gonna happen.

Oh, yeah, the Heights of Sutherland here in wonderful Catalina, AZ?

Got 0.17 inches overnight. “Main bang” still ahead, quite a long ways ahead, considering the passing showers we have now. Doesn’t look like the major band will get here until after midnight, then pound on us most of the day tomorrow. This prediction from the Huskies of Washington’s Weather Department model seen here.

So being on the toasty side of the cold front, should be a pleasant, mostly day with dry spells in between showers, and maybe, if the low clouds break a little, with fabulous middle and high cloud patterns associated with the powerful jet stream overhead (winds at Cirrus levels today and tomorrow should be over 100 mph!) Have camera ready.

Range of amounts from this front, a little in the withering stage as it goes by tomorrow, here in The Heights of Catalina, 0.4 to 1.5 inches, median guess 0.95 inches. Just too cellular in nature to be sure you get hit with all that’s possible, so you fudge on the downside some.

HOWEVER, just viewed the accumulated precip from our great U of AZ mod and it shows about 1.5 to 2.5 inches here, with the model run ending at 1 PM tomorrow–with more still falling! Wouldn’t that be fantastic! Certainly we’d have water in the CDO.

: Precip totals ending at 1 PM tomorrow!

These mod forecasts do tend toward the high side, but I would be very pleased if more than my highest estimated amount (1.5 inches) fell.

So, what’s happening now? Check this loop of radar-sat imagery combo map.

As you will see, rain’s piling up like mad in central AZ just to the west of us. Amounts, according to radar, already well over an inch just for the last few hours according to NWS storm total radar loops from PHX and Yuma. Hah, Yuma! How often does that radar see amounts over an inch in winter?

Below, the Intellicast 24 h radar-derived precip totals ending at 5 AM AST:

24 h rain from radar, ending at 5 AM AST.

I suppose we’ll be complaining soon about too much rain….

Yesterday’s clouds

So much was happening skyward yesterday! So much so, its probably best seen through the U of AZ Weather Department’s time lapse movie here. Its really great and shows all the complications of a day where clouds are moving in at different levels, and there are lots of wave clouds (lenticulars) over the Catalinas to marvel at.

DSCN6320 — 6:59 AM. Altocumulus patches and pastel Cirrus announce a new day.

DSCN6326 — 7:06 AM. A few minutes later, Altocumulus perlucidus join the color display.

11:07 AM. Once again, the rarely seen Cirrus castellanus ("cumulus in a Cirrus) that I seem to notice every week here... — 11:07 AM. Once again, the rarely seen Cirrus castellanus (“Cumulus in a Cirrus) that I seem to notice every week here…

11:44 AM. Hover clouds (Ac len) over the Catalina. — 11:44 AM. Hover clouds (Ac len) over the Catalina, Altostratus above.

1:14 PM. Barging in from the south, the next lower layer, Stratocumulus and Cumulus, bases touched Ms. Mt. Lemmon. — 1:14 PM. Barging in from the south, the next lower layer, Stratocumulus and Cumulus; bases touched Ms. Mt. Lemmon. Sky darkened rapidly and almost eerily right after this.

4:22 PM. The occasionally seen Seattle June sky, overcast with threatening clouds that don't do anything, and with mild temperatures. Tops 0f these clouds were right at the normal ice-forming level here, -10 C (14 F), and by evening, virga and light rain began to fall from them as they deepened up a bit more. — 4:22 PM. The occasionally seen Seattle June sky, overcast with threatening clouds that don’t do anything, and with mild temperatures. Tops 0f these clouds were right at the normal ice-forming level here, -10 C (14 F), and by evening, virga and light rain began to fall from them as they deepened up a bit more.

The weather way ahead

More rain as month closes out. If you don’t believe me, a theme here, check this image out:

Valid for 5 AM AST, November 30th. Of course, I'm not going to show you the actual rain map, I want you to go from this as a bonafide Cloud Maven, Jr. (CMJ). I've noticed that some of you have not yet ordered your "Dri-Fit" TM "I heart spaghetti" tee shirts... What's up with that? — Valid for 5 AM AST, November 30th. Of course, I’m not going to show you the actual rain map, I want you to go from this as a bonafide Cloud Maven, Jr. (CMJ). I’ve noticed that some of you have not yet ordered your sophisticated “Dri-Fit” ^TM, “I heart spaghetti” tee shirts… What’s up with that?

Clouds before the storm

First, let’s see how excited the NWS is about our upcoming major, drought-denting storm, now “in the bag”:

Tucson, here and a nice NWS YouTube presentation here.

Phoenix

Flagstaff

As you will see from these links, they’re getting pretty worked up, and have issued the SAME “Special Statement” for ALL of Arizona, that’s how big the storm is. We’re all in this together. BTW, the U of AZ model forecast from 11 PM AST last night had as much as 5-6 inches of rain indicated in the central mountains of AZ over the next 24-36 h! Will the washes flow here, eventually as the major rain moves east? Hope so.

But, must point that the range of amounts that will fall here in Catalina has to be considered quite large; something from “just a nice rain” (0.4 inches total) to a gully washer (1.5 inches total) due to the fine-scale of the heaviest rainfall bands rotating around the dawdling low over the next couple of days. Its really not possible to pin it down better than a large range of possible values in situations like this, but it does appear that most of it will fall on Friday night into Saturday.

In the meantime, more pretty skies today before the deeper clouds and rain get here overnight or tomorrow morning. Very little rain is indicated here, though, through tomorrow evening,in this latest U of AZ mod run. while inches pile up just to the west and in the AZ mountains.

Yesterday’s clouds

Had pretty skies all day yesterday, even saw some clouds that as far as I know, have no name, these ones below that LOOK like Altocumulus perlucidus but are all ice at Cirrus levels. Could be called, to make up a name, “Cirrus perlucidus” I guess:

7:46 AM. "Cirrus perlucidus." It may be hard to tell for most folks, but these flocculent clouds are all ice. There's a patch of Altostratus in distance. — 7:46 AM. “Cirrus perlucidus.” It may be hard to tell for most folks, but these flocculent clouds are all ice. There is no WAY I would call an all ice cloud, “Altocumulus.” There’s a patch of Altostratus in distance, and an Ac lenticular to left of pole on horizon.

9:49 AM. Altocumulus virgae. Great example of the "upside down" storm; droplet cloud at the top, ice and snow underneath as ice forms amid the droplet cloud, grows like mad and falls out. — 9:49 AM. Altocumulus virgae. Great example of the “upside down” storm; droplet cloud at the top, ice and snow underneath as ice forms amid the droplet cloud, grows like mad and falls out. This finding, first made in the 1950s was surprising because the clouds were liquid at the lowest temperatures.

12:04 PM. Cirrocumulus lenticularis, a bit too thin to be Ac lenticularis.

3:59 PM. Ac lenticular stack in lee of Catalina Mountains. Ac perlucidus in foreground. — 3:59 PM. This view from atop horsey, an Ac lenticular stack beyond the Gap, in lee of Catalina Mountains. Ac perlucidus in the foreground.

4:00 PM. Looking S; buttermilk skies due to Ac perlucidus; lower layer of Ac opacus advancing from the the west below those mottled clouds.

5:31 PM. Brief sunset "bloom" due to a small break in the overcast just over the horizon. — 5:31 PM. Brief sunset “bloom” due to a small break in the overcast just over the horizon.

The weather way ahead

2013112100_CON_GFS_500_HGT_WINDS_276 — Valid at 5 AM AST, December 2nd. A near twin of the upcoming situation.

Now showing up on mods, as November closes out, a low center that looks an awful like the situation we’ll have tomorrow and Saturday, another vortex aloft tracks S along the coast, settling in around San Diego, then moving along to the east very slowly. As you know, weather patterns like to get in a groove and repeat themselves for awhile. Could be we’re in that phase where the SW is a low “magnet” and that would mean above normal precip over a spell of a few weeks. Above, a map for December 2nd at 5 AM AST that looks a lot like what we have coming right up. For that reason, you tend to place a bit more credibility than you might otherwise in a forecast that far away. The exact day this occurs will be most likely be off, but it is likely that a troughs/clouds and precip will to affect the SW over the next couple of weeks or more. Good bye dry spell!

If you don’t believe me, check this 10 day outlook from the NOAA spaghetti factory:

"Lorenz plot" from NOAA, valid at 5 PM AST, November 30th. Its pretty plain to see that there is a strong likelihood of a cutoff low in the extreme SW US. — “Lorenz plot” from NOAA,
valid at 5 PM AST, November 30th. Its pretty plain to see that there is a strong likelihood of a cutoff low in the extreme SW US, if you can find it. (The vast number of contours is due to a software glitch today. Usually only a few upper level contours are tracked.)

Cloud joy; all kinds of ’em; next rain chances on the 21st and again on the 29th

A couple of Pima County gauges reported measurable rain yesterday or overnight, but that was about it. But it was a fabulous cloud day yesterday. Heavier spotty rains, one USGS station indicating over an inch, fell in the central and northern mountains, which is good.

Below, a rehash of yesterday’s great variety of clouds.

DSCN6177 — 7:48 AM. Altocumulus lenticularis clouds beyond the mountains to the SE of Catalina. Lenticular clouds indicate a stable layer of air, one resisting being pushed up, the opposite of what the slender Cu below indicated. So, an usual sky for us yesterday morning.

DSCN6180 — 8 AM. Towering Cumulus atop Ms. Lemmon indicated how unstable the air was just above mountain top level. Underexposed for dramatic silouhette look. The smooth top on the right would be Stratocumulus lenticularis, again an odd juxtaposition.

10:37 AM. Then you had your Altostratus mammatus/testicularis.

3:08 PM. Your Cumulus mediocris topping the Catalinas with a few Altocumulus above; nice shadows and sun quilting.

3:09 PM. And you had your "weak" Cumulonimbus capillatus clouds to the north. — 3:09 PM. And you had your “weak” Cumulonimbus capillatus clouds to the north.

4:09 PM. Dramatic scenes of banked up Stratocumulus over the Catalinas, Altocumulus top side. — 4:19 PM. Here’s a better shot of the Altocumulus perlucidus (here) top side.

4:33 PM. Nice example of glaciating smaller Cumulus remnant north over Saddlebrook. Likely some sprinkles reached the ground under that ice plume. As you know, takes ice to get rain in AZ.

4:34 PM. More sunlight and shadow drama due to Stratocumulus and Ac perlucidus above. Was indoors socializing so didn't see sunset. Hope it was a good one. — 4:34 PM. More sunlight and shadow drama due to Stratocumulus and Ac perlucidus above. Was indoors socializing so didn’t see sunset. Hope it was a good one. I am beside myself thinking about how happy you were seeing all these kinds of clouds in one day!

The weather ahead

Models beginning to act quite well now. A little rain is foretold for Catalina and environs on the 21st of November, but Enviro Can make that storm look more significant and slower to move in, on the 22nd. Still two mods, both having some precip? Its all good. First, for your viewing pleasure and because it portends more rain, from Canada, this:

Valid for 5 PM, November 21st. Low and lots of rain shown banging into Cal. Would be here about 24 h later, or on the 22nd.

Also valid for 5 PM AST, November 21st, this depiction of the flow at 500 mb.

An aside: the Canadian model tends to have a westward bias, that is, a storm is foretold to be farther west a few days out than it turns out to be, something I’ve learned since becoming a forecaster yesterday (hahaha, just kidding, if anyone’s reading this far). So you have to figure the Enviro Can depiction of a trough off Frisco, Cal, is really going to be inland that bit. The US mod output shown above, has this same trough going more overland before it gets to us than the Canadian one, and so there’s less cloud water in it by the time it gets here. Root for the Canadian “solution”!

Farther down the road….more illusory water on the hot highway?

And, of course, a heavier rain is once again over Catalina and vicinity as November closes. This model really likes Catalina and SE AZ! Check it out: