Art Rangno – Page 74

Computer model calculates substantial AZ rains on the 29th, but is it real?

Let’s check, could be goofy, but its all we’ve got right now for a rain, the map below valid for Thursday, November 29th, 5PM AST. The whole series is here.

Of course, the weather sophisticate would want to see what’s “up top” at the same time; see where the jet stream is (brown areas on the map below). Seeing that the J-Stream is right over us, and also being an Arizona precipophile, he might opine, “I find this quite credible.” It also shows massive cold in the West, Rockies, and northern Plains States.

“Who you gonna call”, to establish credibility? Storm Busters! (Or not) Yeah.

Here is the NCEP “ensemble of spaghetti” for this same time, from the SAME model runs, showing the huge system in the West:

Summary of spaghetti: There is no indication of a major cold trough/storm in the West, as would be indicated by a bunch of blue lines dipping down to AZ. Ain’t there.

In fact, its kind of shocking to me that there isn’t the slightest indication of a major trough in this region. So, the actual model run shown in the first two maps turns out to be an extraordinary outllier; some goofy measurements somewhere out there on our globe, got into the model and produced a spurious huge trough, cold and storm.

Amazing isn’t it, that there can be little tipping points due to slight errors in measurements somewhere that can wreck the whole thing, make giant changes from what really is going to happen? And to detect them, that’s why we do the “ensembles of spaghetti.”

What will happen in the next model runs? That trough on November 29th will almost certainly go away. So, the rain in AZ is “real” in the model run, but not real in life. And as we say here, “dang!”

After viewing this spaghetti plot, our AZ precipofile would now look back at those awesome maps for November 29th, and dejectedly, or even with model rage, and say, “Those maps from last night are full of….oops…. have no credibility whatsoever. What is the matter with this model it could even begin to calculate such a ludicrous pattern. Who’s the goofus out there that reported some bad data?” He would not mention a chance of rain late in the month to his neighbors.

This was meant as a “learn you and me up on spaghetti plots” module.

Yesterday’s clouds

Mostly very thick Altostratus clouds with lots of embedded droplet clouds, ones like layers of Altocumulus clouds inside them. Made for a very dull afternoon. Here are a couple of shots:

DSCN3232 — 3:42 PM. Mostly Altocumulus here, some slight virga.

DSCN3234 — 3:52 PM. Same view, 10 min later. Can you see what’s jetting at you?

The End.

Another big Cirrus streamer from the Equator heading our way!

Well, when there’s no rain in the model predictions for 15 days, you have to get excited about something….

Like a solar flare, there has been another massive ejection of high clouds from the equatorial region and its heading toward Catalina, AZ. Here, from the Washington Huskies Weather Department¹, is a 24 h loop of the event. Hope our cell phones still work. Here’s the latest still image:

annotated 201211141030 — Satellite image for 3:30 AM AST supplemented with various interesting annotations, some of which are correct.

What are the ramifications of ejected Cirrus coming all the way from the Equator to Catalina? Pretty skies, sunsets and sunrises, which is quite important to us humans. Also, when it starts arriving today, we’ll have milder nighttime temperatures. Yes, even Cirrus clouds cut down the outgoing longwave radiation leaving the earth’s surface at night, and of course, moderates the incoming visible (shortwave) radiation (sometimes called “sunlight”). We don’t want to dumb this down too much.

After 9-11, when all the aircraft stopped flying for a week some guys at a small university, one so small I don’t think it even had a football team, found that the daytime and nightime temperatures were affected by the lack of contrails. Daytime temperatures were a spec higher and nighttime temperatures a tiny bit lower, suggesting that even CONTRAILS have an effect on the weather and climate. It was an important finding. Of course, without a football team I am clueless, as are you are, concerning what university those findings came from.

You know what gets a lot of us scientists about that contrail study after 9-11, is that something simple and important was done that I (we) could have done had only we thought of it. We’re kind of bitter about it. Might have got a raise, too, got the name out there. Citation index fluffed up some. We’re dealing with a lot of loss here. Heck, you probably could have done this, too, it was that easy.

The study of contrails is a pretty big topic these days, though the effects are deemed small for the present. Here’s a short article for you. Here’s an unrelated one, one about smog’s effects on clouds, but one you should read, anyway. Might be true. Reading the second one is like doing an extra pushup. Its good for you. And me since one of the authors of the second article (Danny Rosenfeld) criticized me (and Pete Hobbs) royally in print in the late 90s only because we said his work was invalid. Show’s I’m magnanimous, following the ideals of science meaning that as scientists we have no personal feelings about our detractors.

Yeah right. Check the climate blogs and those ones who refuse to allow other scientists to even comment on their work! Its a hideous situation out there now, far from the ideals of science where one WELCOMES criticism. But, I diverge….getting worked up when I should be concentrating on clouds.

BTW, that little blob of clouds north of the ice cloud mass coming at us, is due to a little disturbance that will hit the coast of Cal in a few days. With it, the clouds here will get pretty thick, probably as will happen later today or tomorrow with the ice clouds, causing the optical depth to exceed 4.00000000000 (4).

What does an optical depth of four mean?

That means that the sun’s position is not discernable. (Also, can’t be a Cirrus cloud, BTW, but rather Altostratus if its an all ice cloud). Optical depth is usually something used by the smog folks. A really clean sky has an optical depth of 0.05 or even less. Smog laden skies, such is the coastal areas of southern California, or back East on humid days in the summer, have optical depths of 0.2-0.5 at times, horizontal visibility might only be a mile or three; the leaves are gray and the sky is brown, as the song says. Aren’t we happy we don’t have that kind of smog?

Looking way out, just now, I saw this in the ensemble of spaghetti, thought you should see it, too.

While no weather beyond warm breezes and high clouds is portended here, where would you really like to be in the West in two weeks or so for some really heavy rains? Can you tell? What’s a place I mention too many times when comes to Cal rains? Yes, the King Range around Shelter Cove, between Frisco and Eureka. This plot gives high confidence to major flooding in northern California in the 10-15 day window. Why? Because so many of the blue lines (564 dm height contours) dip down toward the tropics in the eastern Pacific in support of the actual forecast from last night (represented by the yellow lines). Remember that the blue lines result from small errors put into the model runs at the beginning to see how robust a forecast is. The wilder the spread of the lines, the less reliable a forecast is. The more they group together, the more robust, more reliable a forecast is. They look fairly bunched up in the eastern Pacific, and this is the reason for having this plot here today. I suspect we’ll be reading about heavy rains in Cal during that 10-15 day window. It will be fun to see if we can make such a call so far in advance!

The End.

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1Nobody knows your university by its scientific accomplishments, but only by its athletic accomplishments. Its been written up. I certainly wouldn’t. If online universities could have football teams, it might be the end of “brick and mortar” universities.

In case you were wondering where those high clouds came from…

From down there, as seen here.

More of those high clouds, and we hope with some Altocumulus, will be dropping by from the deep tropics over the next week or so.

Camera alert: Sunsets and sunrises will be spectacular at times over this period and with more than one layer, there is more than one dominant color.

The saddest headline ever read re the coming winter? From the Climate Prediction Center here:

“El Nino watch discontinued”

They’d been talkin’ up an El Nino this winter and spring for months! And, as you know, El Nino occurrences tend to cause wetter winters here. Doesn’t mean we still can’t have some good storms, but the odds are lower.

Yesterday’s clouds

SONY DSC — 3:38 PM: Pretty Cirrus/Cirrostratus from near the Equator.

Next rain in 9-10 days?

The NCEP model, using last evening’s global data, produced some green pixelation in Arizona (light rain areas are green in the model run output) for Monday night into Tuesday, November 19th-20th. However, look below at the NOAA ensemble of spaghetti plot for that day. I don’t see any rain here. Do you?

Cloud-maven juniors would be so scoffing at the thought of rain in Arizona in a computer prediction that is associated with a spaghetti plot like this for that same day! For confidence in rain that far ahead here in Catalinaland, we would need a plot that shows something like you see over Japan (upper left); the lines all squeezed together. But you don’t see them here, do you? They’re a mess, indicating the model is generally clueless about what will happen here in 9-10 days. So, while it could still happen, it has to be considered a very long shot.

MOnday Nov 20 spag_f216_nhbg — Forecast map for Monday, 5 PM AST.

Here’s the WRF-GFS model output, rendered by IPS Meteostar that shows rain in AZ, a model run in that had this green pixelation (areas where rain is forecast to fall in the preceding 12 h) for overnight Monday into Tuesday morning, the 19th-20th. Nice, but wrong. The entire model run, is rendered here in case you think I am lying about this.

I’ve added an arrow to help locate Arizona for you.

So, in view of the ensemble of spaghetti, can’t count on green pixelation remaining in Arizona in future model runs. Not starting out as a good day today.

Yesterday’s clouds and skies overall, how nice.

First, the “stratiform” clouds that were still “sprinkling-its not drizzle” as daybreak came. Then the blue skies dotted with Cu.

Raining hard here at 4:08 AM

Little cell going by (aka, weak Cumulonimbus). I hope you’re up to enjoy the sounds of a good cellular rain on the roof. I feel like another song coming on. Ooops, same one, but its a good one because it not only has rain and thunder in it, but also pathos¹. (I thought the thunder in this song gave it a lot of dramatic impact, and we had some thunder NE of Saddlebrooke yesterday afternoon around 2:45 PM.)

Cell has added 0.03 inches to our 0.13 inches and this morning’s total is now a quite nice 0.16 inches on top of the 0.30 we got yesterday. Raining harder now after it let up! Oh, that didn’t last long. Dang.

Total here at 6:55 AM: 0.18 inches! Two day total here, 0.48 inches.

This is so great since this second part of this two part storm was “marginal” as a rain producer, might have only produced 0.05 inches as the bottom estimate for rain, made a few months ago (just kidding), with a top possible amount of 0. 40 inches. So, we’re getting close to the middle of the prediction range made so long ago, 0.225 inches, a prediction you may remember, one that was based on spaghetti.

This rain is associated with the strong cold front that passed through Catalinaland about 2 AM, just after those strong gusts occurred, 30-40 mph last night. Here’s what the nighttime temperature did, drop 14 degrees!

And, as you no doubt know, the atmosphere pressure goes up instantly as the cold front goes by and the colder heavier air piles on top of you. (Time hacks don’t match on these charts for some reason–have not noticed that before….)

annotated 2012101009_Cat temp drop — Arrow points to passage of cold front at Catalina, AZ.

annotated pressure 2012111012 — Atmospheric pressure on top of you here in Catalina, AZ. Arrow denotes cold front and rise. With this denser air, you may notice that you’re having difficulty getting up, moving around as you push more “molecules” of air around for any given movement compared with yesterday when the air was not so dense. It also might be because you have more clothes on today…. Hahahaha

Here’s a really nice link to radar happenings locally from The Weather “Underground” (nothing to do, BTW, with “The Weathermen” of the 1960s-70s even though it sounds like it).

Learning module….skip if bored already.

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One of the things that is happening right now at 5:01 AM LST, is that cells are appearing on the radar or intensifying as they move toward Catalina. This happens a lot when the air at cloud height is moving toward the Catalinas and upslope toward Oracle and Mammoth, getting squeezed between the Tortolita Mountains and the Catalinas. That lifting makes the tops go up to higher colder levels, and when the tops to the west and southwest are too warm for ice formation, say above -10 C (14 F), then just a bit of lifting triggers ice formation making a cloud “visible” on radar as the ice grows in size into snowflakes, maybe collides, too, with some itty bitty cloud droplets (too small to be seen by radar) growing even larger and falling faster. This is maybe the biggest reason why Catalina has so much more rain than upwind areas (17 inches annual rain) compared with about 11-12 inches upwind. Most of that difference comes in the wintertime in situations like this, and so some extent, like yesterday’s more general rains.

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What’s ahead for today?

Back edge of this rain band, more or less solid clouds dotted with deeper ones producing rain, is on the doorstep.

Here it is as of 4:45 AM from the U of AZ Weather Department Satellite Facility, with a CONSIDERABLE amount of arrows and writing on it:

So, according to this “diagram” the back edge of this band on the sat image should be here by no later than 10 AM today, that is, chance of additional rain up until around 10 AM in a brief shower, but only a hundredth or two likely. After that, just clouds, probably a lofted Stratocumulus layer, then a widespread clearing with scattered to occasionally broken Cumulus.

Since it is so cold aloft now with the freezing level around 5,500 feet (snow shower now (7:29 AM) on Samaniego Ridge), ice will like form even in modest Cumulus clouds this afternoon, that means virga or maybe an ISOLATED light rain shower possible through around dusk.

Yesterday’s clouds

Here are some of the best cloud photos from yesterday, such a pretty day here in Catalina, where Cumulonimbus clouds stayed just to the north of us off and on all day.

The End, at last!

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¹Actually, I made it sound like I wrote this song in yesterday’s blog, but in fact, I did not, though I WOULD have if I had thought of it. Note that the person who uploaded this song to You Tube, did not know how to spell, “Cascades.” No wonder we’re falling behind.

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Hel-lo-ooooo, its 3 AM and raining, and you’re not up

That’r right, real cloud maven juniors get up in the night to experience all the raindrops they can after a droughty period. Been up since a little after 3 AM; its now 4:07 AM with an accumulation of 0.16 inches, a Dust-B-Gone amount, of which I have experienced exactly 100% of it as an audible event on a thin Arizona room roof. Its great to have a thin roof so you can listen to the rhythm of the falling rain. I feel like writing a song…

Quite nice, too, to hear this after SO MANY weeks of nothing except litho and bio meteors, i. e., dust and spores, Burrow weed and desert broom seeds floating in the air, and other untoward aerosols and particles that are best left on the ground.

Listening to rain on a roof can be used for meditation purposes, letting life’s questions resolve themselves without really trying, like, what are those ants going to do NOW with their wonderful little symmetric cones? Did they know it was going to rain and close the hole up in time? Note tire tracks and resiliency of ants… Says something about bouncing back after a disaster.

Why is it raining? Got us a little stream of tropical air in the mid-levels of the atmosphere that had been meandering off Baja. Mods saw this coming, maven was skeptical, but what’s great NOW is that we here in Catalina seem to be getting the most out of this little plume of moist air. Here’s a sat loop:

First, this just in: 0.22 inches at 4:22 AM! I am beside myself with joy!

This just in (again): 0.30 inches TOTAL by 6 AM. Fabulous.)

Here is the sat-radar loop from IPS Meteostar and below, these sat and weather map images from the U of WA Huskies Weather Department showing the little blob of clouds “that could” (get here and rain on us). You can see how that Big Trough (over Pac NW) swept it toward us, kicked it in the butt. There is some writing on these images to help you understand them; point things out for you. I really went out of my way here.

annotated 201211090900_300mb — Today, at 3 AM as the rain begins.

Notice the big gap between the little cloud patch over us in the 2nd map for 2 AM this morning and the band coming across California. Means there’ll be a break in the rain here until late tongiht or early tomorrow morning when the Big Cold Front with the Big Trough arrives here. Until then, just the gusty winds and some pretty clouds, filling in from time to time, maybe some rain visible to the north of Catalina.

Yesterday’s clouds

Below are a couple of photos of those nice Altocumulus castellanus with virga that came in rolling in across the sky suddenly yesterday afternoon. Actually, when they grow into real shower preoducing clouds, they’re also transitioning in name to Cumulonimbus (Cbs) clouds, though they are weak ones, not like our summer variety.

If you really looked, you could see that the bases of the Altocu/Cbs were well above the freezing level by noticing all the snow virga dropping below the bases. The TUS sounding suggests that the bases were at 14,000 feet above sea level (around 11,000 feet above the ground) and at -5 C (23 F).

Too dry underneath for much of the precip to get to the ground.

The rain before the storm

Our models have been showing a batch of scattered showers on Thursday for some time, a precursor to the Big Change day on Saturday. Skepticism prevailed at this keyboard since there didn’t seem to be much going on off’n Baja where this moisture was supposed to come from. Here is an upper level chart demonstrating that assertion: don’t see any contour circles out there do you? Just a wandering, single contour off Baja, not much going on compared to that behemoth trough blasting the Pac NW.

But, by golly, there IS a patch of clouds and moist air in that weak circulation off Baja that is going to be swept out of the eastern Pacific by the “broom” of the flow around that giant upper trough that moves toward us from the Pacific Northwest into the Great Basin area on Friday and Saturday, generating a powerful low center at the ground as it does. Some Cumulonimbus clouds have even formed off Baja in this weak tropical circulation, and here, that should mean some nice Altocumulus castellanus clouds tomorrow, likely with virga. Cirrus will also be around for a real visual treat. As we remind reader (s), get your cameras ready. Could be some spectacular scenes; sunrises and sunsets.

Here is a link to what is going on out there (from the Huskies, of course, the Washington ones.) Those white specs that appear and disappear off’n Baja are little Cumulonimbus clouds, showing that the middle levels of the air out there is very unstable. (Those are a type of Cumulonimbus that sit on top of boring Stratocumulus clouds, FYI)

What could be tremendous for us is that the Wildcat model (here), has off and on showers from this tropical surge for no less than 24 h! Amazing. I just now saw this from last night’s run.

Could it happen?

Well, this model is smarter than you and me, and so you figure there is going to be a lot of mid-level clouds and castellanus (spire-clouds) the size of small Cumulonimbus clouds as we see offshore now in the sat images. And with that, the likelihood of some thunder here and there. This preliminary action is getting to be so much greater than I possibly could have imagined; rain in the immediate offing, not waiting until Saturday!

One of the things that will happen tomorrow, too, with this little slug of moisture and clouds, is that the lower level humidity will be increased some as well; it won’t be just middle and high level clouds that increase. That will help juice up the air before the Big Trough gets to us, maybe helping that Saturday rain out just a bit. Ironically, this little thing ahead of the BT might well produce more rain in a thunderstorm than the BT with all of its drama, the strong SW winds on Friday, frontal passage and wind shift to the NW overnight or early in the morning, and such.

With BT, strong winds are guaranteed on Friday, it will really seem like the season has truly changed which is kind of cool. Rain still looks marginal from BT; could be just a few hundredths, though the “window” is still there for more than a quarter of an inch if everything is optimized (storm hangs on longer, jet stream is a little farther S than predicted, etc.)

The weather ahead

It does appear that we’re headed for a new wet regime after our long, warm dry spell since mid-September with persistent high pressure over us and the West Coast. Last night’s global data, crunched by our super model WRF-GFS, had rain on SEVERAL days after these two chances go by tomorrow and Saturday due to the passage of more troughs plunging in from the Pacific. The pattern we’ve had, warm in the West, cold in the East is fairly common one because the jet stream seems to like to do that, sometimes, as we have seen, for weeks at a time.

But now that pattern is disappearing and a new jet stream pattern is taking shape, one that will likely mean normal or above normal rains here over the next month or so as this new pattern gets locked in for awhile. With those once-in-a-while rains will be below normal temperatures.

A pattern like this, “cold in the West”, almost always means warm in the East, and so the really cold air those unfortunate folks affected by Sandy have been experiencing will soon be gone, a good thing.

Here’s an example of a trough predicted to be over us from last night’s global data on November 15th:

Nice, huh?

The End.

Precision forecasting of the next Catalina rain (an experiment)

After looking at last night’s model run, and the many model outputs before last night, here’s the “skinny” as this forecaster sees it (“as I see it”, means this is an experimental forecast to see how close it can be called. Its gaming the weather. Here goes:

There is a 100 % chance of rain in Catalinaland on Saturday, November 10th (sometimes referred to as “football day” this time of year). The rain will begin between 5 AM and 11 AM that day. It should last a couple of hours or maybe a bit more.

It will be horribly cold. You don’t want to be out on Saturday, November 10th.

The amounts?

In a “mental ensemble” of the best and worst outcomes for this rain situation, I see a bottom (only a 10% chance of LESS) in this rain event as a puny 0.05 inches and the top (10% chance of MORE), 0.40 inches (nice!). To get the best estimate of what will actually fall, take the average of these two, 0.225 inches. So, that’s my forecast, 0.225 inches on Saturday here in Catalina. Get your micrometers out! hahahaha.

Here is the model depiction (WRF-GFS from NCEP rendered by IPS Meteostar) of the air flow at around 18,000 feet above sea level. Recall that rain is pretty much impossible here until the maximum wind at that level goes by. Below is a snapshot of the air flow and its speed for Saturday, November 10th at 10 AM. As you can see below, the red core of the highest winds at 18,000 feet (aka, 500 mb level) is passing overhead then. So, expect it to be raining by then around here. The whole loop for this level is here.

I think you can do this today, cut it so finely, and so far in advance of the event, because the model runs have been SO consistent and in the NCEP’s (Nat’l Centers for Environmental Prediction’s¹), “ensemble of spaghetti” outputs, have been indicating a strong signal, high reliability for this event for a good ten days. So, count on it, though obviously the timing may be off a few hours, but that’s about it. Everything else is pretty much a “done deal”, and you don’t often get to say that this far out (six days). Below this jet map is a snapshot of the high reliability of this forecast as seen in spaghetti. Packing together of the blue and red lines indicates where the forecast is extremely reliable, and that’s what you see throughout the West from last evening’s plot.

Since this is the cloud-maven blog and not the forecasting-maven blog, I’ve added a pretty cloud picture at the very bottom.

The End.

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¹formerly, and more simply, the US Weather Bureau)

From a couple of days ago, pretty sunrise Cirrus fibratus/uncinus and pretty junior Cirrus fibratus/uncinus

“Trough, there it is”,

Again, paraphrasing a skit from that old, innovative TEEVEE show. In Living Color, featuring Jim Carey, the Wayan Bros. etc., to describe the results of this run of the NCEP “ensemble of spaghetti” plot. This is a great output! Mmmmmmm, makes me want to throw a meatball on it right now! As in yesterday’s presentation from this keyboard, this plot is valid for football day, Saturday, Nov. 10th, at 5 AM AST. (Cloud pics at bottom.)

What’s to make of it?

Plan on being cold, very cold, my friend (s)—plural if there is more than one reader. There’s no way of avoiding being cold now on the 10th and for a couple of days after that. There’s probably going to be be some minimum temperatures in the 30s, maybe lower in the washes.

What this plot shows is that the signal for a huge temperature change pm the 9th-10th is very strong; its not gonna go away. And that is shown by the blueish lines that are packed together and dip toward Arizona with a lack of lines to the north of us over Nevada-Utah, Idaho-Montana into Canada.

Where the lines bunch together indicates where there is high confidence that the predicted pattern (yellow lines) will happen. You can see that the red lines are also VERY bunched south of AZ, another strong confidence indicator. Also, at this time of year, those blue lines indicate where the jet stream will be, along the 5580 meter height above sea level line, the height where a pressure of 500 millibars (mb) will be found, to add some complications to this discussion.

Below is what the model actually predicted at 500 mb from last night’s global data taken at 5 PM AST, from IPS Meteostar with the map valid for 5 AM AST, November 10th. At this point, the cold air has already arrived here in Catalina, likely the evening before. However, if the winds aloft are what is predicted, we’ll likely be dry. Dang!

In model run after model run we are going to see predicted, almost the same thing; a big cold trough barging into the West with the jet stream dipping way down into AZ. Along with this exciting development, a strong, strong low center will form inland at the ground, probably over Tonopah, NV, where they like to nest. That low center will bring our first really windy day as it moves toward Utah, probably beginning on the 9th when the temperature is still comfy.

Then after those strong SW winds, an extremely sharp cold front will go by in which the temperature plunges maybe 10 degrees in an hour or so as the wind shifts to the NW, probably on the tenth. Maybe you should think about getting a new, better thermometer/temperature sensor to document this. Just a thought.

So, our cold event, like the movement of the Sandy the Hurricane, is well predicted though the exact timing is still, of course, fuzzy. But count on something like this happening here in SE AZ.

Cultural impacts of sudden cold air:

Let’s see if the AZ Cats have a home game on the 10th….. Oh, my gosh, its Homecoming for the AZCats! Maybe they should practice in a large refrigerator after all these warm days. Fortunately, they play Colorado, a really crummy team, so maybe they won’t have to practice that much. :}

Rain with that cold air?

It looks marginal since the passage of the jet stream aloft is nearly overhead so far, not much if any of it to the south, the wintertime requirement for rain here. So, if there is rain, it will be a very slight event. But, will have nice clouds banking up against the Catalina Mountains for a day or so in that cold air.

Farther out: the models are suggesting this will be the “new pattern” for a few days, that is, it will recur, and another trough heads this way after this one, so we’ll have another chance for rain a few days after this upcoming cold spell.

One great aspect of this “new pattern” is that droughty areas of the Plains States will get hammered with substantial rains and snow, good for the winter wheat crop, and thus, all of us!

Pretty cirrus makes for pretty sunsets; these from yesterday:

The End.

Big weather change coming about November 10th

The evidence is clear, see below:

annotated nov 10th spag_f240_nhbg — Ensemble plot produced by the National Center for Environmental Prediction based on global data taken at 5 PM AST last evening. Arizona, I think, is shown by an arrow. (Actually this was a faulty run having too many contours; still there is something for us to glean here.)

Or, maybe should it be, “clear?” Or, “Huh?”

Of course, the two people who read this blog know that I am a big fan of these spaghetti plots, as they are known by in the business, in elucidating the likelihood of coming weather events shown on the progs.

Today’s prog has a huge trough barging into the West at this time and again a couple of days later.

0001VZ — Valid Saturday morning, football day, November 10th. Produced by last evening’s global data taken at 5 PM AST.

But previously, these same models had a gigantic hot air containing ridge building over us between the 10th and 15th (see it here: 15 day forecast Nov 15)! Now that same model has a couple of big troughs coming through the West at that time. So which ouput is likely to be right?

By examining the spaghetti plot, it’s PLAIN to see that its the trough of cold air that is very likely, and NOT an upper level, desiccating ridge of hot air sitting over us on November 10th. Notice that there are a lot of lines swirling southward and then curling back to the north over the West Coast (look just to the “left” of where Arizona is). Well, take my word for it as a meteorologist. Hmmm. I guess that’s not the most reliable person you would want to take his word from when it comes to weather 10 days out…

Instead of hot air over us in two weeks, an invasion of uncomfortably cold air marked by the passage a sharp cold front is almost in the bag on the 10th-11th. There is a slight chance of rain, too. Rain, what’s that? Well, it falls from “clouds” and there should be some sun-blocking “clouds” with that cold front.

Get your sweaters ready.