Category Archives: The weather WAY ahead (10 days or more)

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.

 

“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:

5:42 PM.

The End.

 


 

Big weather change coming about November 10th

The evidence is clear, see below:


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.

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.

Catalina dust to be vanquished today (?)

“?”?  It goes with the predicting the future territory…

Raining at 4:19 AM!  Pretty good sized drops!  Wow. Current NWS forecast now says rain only after 11 AM so an early start is excellent.

Moisture is moving rapidly into southern Arizona.  As an example, look at this uptick at Sells, AZ to the SW of us (green line in top panel).

The satellite view is also promising with a bank of Stratocumulus with buildups (castellanus-like) to the SW moving rapidly this way.  Take a look at this, courtesy of the U of AZ, and if you look closely you’ll see some whiter specs appearing indication that a few of these clouds are getting colder tops compared to surrounding clouds.

Those whiter tops would be small Cumulonimbus clouds with rainshafts in that mass of clouds entering AZ.  So, there’s a whole mass of those little guys scattered here and there in that mass of clouds heading for us.

Not likely to get too much rain out of them, however.  The rain from the clouds over us now and immediately upwind is falling from clouds that are not connected to the ground and so the updrafts in them tend to be not so great.  Higher updrafts usually means that more falls out the bottom if the tops of the clouds can reach that magical -10 C level up there where ice can begin to form.

Later in the day, as it warms up, the updrafts will be rooted at the ground and be stronger as the moisture revs up and with that, the chance of an organized line of showers moving in during the evening, one that might last an hour or two, goes up.

One caveat:  The U of AZ mod from their 11 PM AST run (here) doesn’t see ANY rain in Catalina today, tonight, or tomorrow, which seems surprising (and likely bogus as estimated from this keyboard).  It could be those clouds to the south, and the moisture intrusion we’re now getting were not seen in the data at the beginning of the model run.  This output does, however, indicate that we are in a marginal rain producing situation. Usually this model is quite good.

24 h rainfall ending 5 AM tomorrow, October 12th, a truly horrible depiction.

 

Don’t really know what’s wrong with the model, but it does seem like measurable rain will fall in Catalina, though its likely to be less than 0.25 inches.  Will be pretty happy, since it is a marginal situation, if we get more than 0.10 inches, something to settle the dust and clean the desert vegetation up a bit.  At the least, there will be some interesting clouds to look at!

A few more drops here at 5:13 AM!  Excellent.

Looking way ahead, 14 days or so.

In the longer view, more rain for Arizona is seen, of course, in the 10-15 day model prognosis, possibly substantial ones.  But last time this was predicted in the models,  “upon further review” we saw that those rains were associated with a model run was an outlier of some kind, plain goofy, when we looked at the NOAA-NCEP ensemble-spaghetti plots, dammitall.  So all that rain in AZ in THAT model run was almost certainly bogus.

But, once again the the models came up with some pretty good rains in Arizona, these rains derived from the model run using 5 PM AST global data from last evening.  These rains are more “robust” in terms of confidence.

In fact, the situation we have right now, and the one predicted in 14 or so days, are rather similar in appearance in the spaghetti plots.   Our current incoming upper low center was quite well predicted more than 10 days in advance when one examined the “spaghetti” plots.

How about the rain prediction below, goofy or what?

To answer that query, we’ll go to our friend, the NOAA NCEP ensemble-spaghetti plots here.  We need to have a trough in upper levels, just like now, to have rain in the cool half of the year.  Will there be one?

Gee, can’t do that based on last night’s data.  No ensemble “bad balloon” plots done yet.  Will have to wait, but the spaghetti plots from the night before last were encouraging.   Will update this discussion when the new spaghetti plots are producted.  So, after all this discussion, we’ve kind of ended up with nothing!

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This word just in minutes ago from NOAA-PSD where the ensemble plots are displayed.  “System down for maintenance.  Should be available later today.”   Great. Then I can really ruminate on those spaghetti plots!

Pretty clouds out now (8:46 AM), take a look if you have a chance.

Tomorrow, we’ll talk about CLOUDS!

 

Valid for Friday mroning, 5 AM, October 26th. The green areas indicate the rainfall the model expected in the prior 12 h. As you can see there is a lot of coverage in AZ.

 

 

 

 

Rain ahead and then way ahead as well

First of all, nice Cirrus-ee clouds yesterday…. Cirrus fibratus left, Cirrus uncinus (with tufts at the top, filaments of falling snow below) on the right.  What is remarkable to me is the finely stranded nature of these clouds.  With an aircraft, you would hit, in one of those strands, a burst of ice crystals just 10s of yards (meters) wide, some only about 10 yards (meters) wide.  Those crystals falling out in strands are the largest ones to have formed in these clouds, though they would likely be no more than a few human hair’s width in diameter (around 300-400 microns).  You would think that any turbulence up there would disrupt such delicate strands, but here, anyway, it doesn’t.   The snow falling out is more like a fall of dust, the crystals are so small and light, the kind of snowfall they get at, say, the top of Mt. Everest at 29,000 feet.

 

 

 

 

 

 

 

The weather ahead

Rain 1:

Begins later Thursday.  Agreed on by Canadians, NOAA, U of Washington’s  WRF-GFS more finely gridded model output,  etc.  Its “in the bag” I would say.  But, what exactly is “in the bag”?

Amounts: worst case, trace, best case, 0.25 inches by Friday morning, daybreak. OK, its not that much.  We’re struggling here to get a cloud here below 20,000 feet though, so we should be happy with any liquid that falls out of the sky.

NOAA model for the 500 millibar pressure level here

Surface maps with rain on them here.

Rain 2:  the big one maybe; getting more hopeful.  Complicated discussion below.

The models have shown a gigantic trough and low pressure system developing in the Great Basin every so often around the 20th of Oct, but then it has disappeared.  Looks a bit more reliable now since NOAA/NCEP spaghetti plots are showing something at that time reflecting this huge change in the jet stream.  The spaghetti plots had nothing earlier when this huge trough was forecast,  indicating it might be a huge bogus-outlier model run in which one could have little confidence in.  Now they got somethin’.  Below is an example of that “somethin'” in those plots, valid for 5 PM AST, October 20th.

The yellow line is the actual model run based on last evening’s data.  The blue lines are the “bad balloon” runs, where slight errors, or differences in data are used to see how robust the actual predicted pattern is.   If the blue lines and the yellow ones converge over one another in an area, like they do south of Japan-Kamchatka Peninsula in the western Pacific, then the forecast is reliable; “count on it.”

Is our forecast as reliable as the one for the western Pacific on the 20th-21st?

Nope, as you can see by how wide the spread of the blue lines is compared to that in the western Pacific.

BUT, the “bad balloon” blue lines ARE poking down to the south along the West Coast, “trending” toward the yellow line (last night’s actual prediction with the data as it came in).  Those blue lines are close to where the jet stream is going to be located with deliberate errors introduced.

So, there is a strong indication that the jet stream will at least dip southward along the West Coast because even with slight errors, it still does that, trend southward along the West Coast.  Now this is exciting, even if there is some remaining uncertainty on exactly how it will play out.  If nothing else, we’ll certainly be on the edge of some strong system about the 20th-21st.

The really picky eye will see that the yellow line (that reflecting a jet stream contour from the actual model run based on last evening’s global data) along the West Coast is still a bit of an outlier (that is, its outside the zone of the most blue lines).  Pretty much all of the blue lines are north of the yellow’s position.   So its very possible that we could end up with less of a trough along the West Coast than was predicted in the actual run using the global data as it was.   I guess this is confusing, but I am trying to make it less so, with little apparent success.

How much rain is foretold presently in “Rain 2”?

Below is a panel from last evening’s global data crunch for valid for 5 AM, October 21st.  You’re gonna like what you see:The colored regions are those in which rain is forecast to have occurred over the prior 12 h, meaning the rain likely started Saturday afternoon, the 20th here.

What’s fascinating is that in all these model runs, there has been a tropical storm/hurricane shown to the south of us.  Sometimes it fades away, or moves over New Mexico, but its always been there.  What’s fascinating #2 is that again, it is a hurricane that hasn’t even formed yet, but the model detects a “signal”,  a pattern, a combination of factors that will come together to form a tropical depression, then a tropical storm, and then a hurricane that is caught up in all the upper level goings on in the West. In the latest model run, one panel shown below, that fading hurricane is approaching Baja and its remnants are now drawn into Arizona.

So, there, in that hurricane remnant, is where the potential of a mighty rain lies on Saturday evening into Sunday, the 20th-21st of October.  Models are indicating 1-2 inches in portions of AZ over a 24 h period with this situation. Us?   About half an inch in 24 h, but stand by.

So, lots to hope for….

There is yet one more suggested rain (Rain3) after “Rain 2” so it would seem SOME rain will fall in the next two weeks!

Low temperature records galore

Here a very nice site if you want to look at what weather records were being set around the country, with an example for the past few days below.  The one below were set as a gigantic blob of cold air (high pressure region) plopped down into the US, one bigger and colder than usual for this early in October.  There are a ton more low temperature records being set today.  As you know, this cold air event was well predicted in the computer models many days in advance and was blabbed about here.

Does this exceptional cold air in early October presage a cold winter?

Well, to know for sure,  sort of, we go to the Climate Prediction Center to get their best guessestimate, and then look at natural phenomena, used by folk long range weather predictors, like the height of ant cones, length of horse’s hair, etc.  The CPC’s outlook, the best info around, beats Farmer’s Almanac by quite a bit, kind of like the way my former employer’s sports football team was beaten down by Nike Team One in Duckville, Oregon last Saturday evening, 52-21; wasn’t close.  Let’s see what the CPC sees for the next few months:

 

Wow!  This is not what I expected to see for October, November and December  because of the current weather regime with all that record cold in the very areas where warmth was expected.

This CPC prediction suggests that the cold air now in the East is a fluke and a quite comfy, energy-conserving fall season should be observed where the low temperature records are falling today.  This CPC longer range prediction would go with an El Nino-influenced winter, but so far, the overall pattern has not looked much like one.  Of course, phenomena like the El Ninos/La Ninas, when they are strong,  are the best hat racks to hang our climate prediction hats on these days.   The El Nino we have now is pretty marginal, barely made the criteria for one; a crummy hat rack.

The above seasonal forecast by CPC was issued on September 20th and a new prediction will be issued shortly.  Usually, though, they don’t “yo-yo” much, that is, change much from one month to the next in what is foreseen for the next three months;  there’s some inertia involved.

BTW, and oddly, one of the severest winters in the East was associated with a very weak/marginal El Nino in 1976-77, a year also that included extreme drought along the entire West Coast through February.

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Folk weather predictions; ant cones (are they really better?)

Now lets look at ant cones and see what we can make out of those.  Perhaps ants know something about the coming winter since they’ve been around for about 10 billion years1.  Maybe there was something in our summer temperatures and rains that “spoke to them” about the coming winter. Below, a typical ant cone of the size around now.

You know, I’m not getting a lot out of what these ants are trying to tell me about this coming winter, though, its very nice.

So, for the present, and with no strong climate signal anywhere, we have to assume that the early cold is a fluke, not an indicator of a whole winter.

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A little rain is but a few days ahead, Thursday.  In the meantime there have been some nicely patterned Cirrus, Cirrocumulus, and Altocumulus streaming out of the very same system that moves over us Thursday evening.

There will be more of these photogenic clouds today and in the days ahead of the storm.  Keep camera ready!

It will be fun to have more dramatic skies and some wind with a “storm” finally.  Mods have another one a week or so later, too.

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1I’m exaggerating here since the entire universe, one that began with a spec smaller than the head of a pin and yet had everything in it, is about that old.

 

Rain here in Catalina by 5 PM, Thursday afternoon, October 11th; update, Canadians hop on Catalina rain train

It says so right here, from the University of Washington Huskies’ model, after a LOT of calculations.

Take a look at the map below, valid for Thursday afternoon at 5 PM AST.  Those colored regions denote areas where Mr. Model thinks it has rained in the prior 3 h.  BTW, if you want to see all the choices of stuff you can look at, things that a model calculates, go here to the WRF-GFS “36 km grid spacing” home page.  Its pretty amazing, mind-boggling, really.  And that is only a fragment of the calculations it did based on the 5 PM global data from last evening.  It seems to look like a tenth to quarter-incher or so right now for Catalinans.

Below is the upper air pattern that goes with our rain.  As you can see, there is quite the little spinning top of an upper low over southern California, northern Baja.   You may even recall if you’re under thirty, that the “spaghetti” plots virtually guaranteed a low in the SW with the main jet stream far to the north some 10-15 days ago.  So, here it is, and it appears to be in a position to give us some rain–that part of this situation was definitely in doubt, even if the presence of a low near us wasn’t.  If this low had ended up over Vegas, forget rain.  But all of the models are now predicting this low center will be in a position to put an end to dust here beginning later Thursday.  Excellent.

Since I can’t think of anything else to say, really, I thought maybe you’d like to look into the face of a horse and wonder what it was thinking.

Jake.

The End.

No!  Breaking news!  This just in! ” Live at 11″ “Right or wrong, you heard it here first!” etc.

Look what I just saw from last evening’s  11 PM AST model run from NOAA.  Its fantasy weather because it is so far off, but what a fantasy!  A giant, mind-boggling;y large, intense low center forms over Utah and draws the remnants of a tropical storm hurricane (purple region) into Arizona!  Man, it so exciting to see these kinds of “outlier” forecasts, even if you know they’re not likely to be realized, but “not likely”, is NOT impossible.  And that’s the hope and excitement here; it could happen.  Below two maps for your viewing pleasure for “only” 360 and 372 h from now, that is, Saturday night into Sunday morning, the 20th-21st of October.  Not only is there substantial rain predicted, but, its really windy too, a real storm!

 

 

—————————————————————————————————————————————————————-More updatingfor next week’s rain possibility from 12 Z (5 AM AST) Canadian model run).  In sum,

Canadians hop on Catalina rain train.

First, from last night’s 5 PM global data, there’s no rain in SE AZ (check lower right panel). Now, just 12 h later from global data at 5 AM AST TODAY, a new run has a lot of rain in SE AZ!

From 5 PM last evening, this from Canada.
From 5 AM this morning, this. Check out all that rain in SE AZ. Excellent (look above the word “above”).