Let’s look at drought…

The best place to go is to the Climate Prediction Center to see how much drought is going on and what their thoughts are on the future of drought.  Apparently they don’t think there is enough drought west of one of the current baseball epicenters, St. Louis, and they have foretold persisting drought where it already is for the most part, and also that it will spread northwest into the Pacific Northwest (2nd map below).

First, the current scene, as rendered in the “Drought Monitor“, hosted by the University of Nebraska, Lincoln, aka, Big Red:

 

Below, CPC’s forecast through the end of this year (December 31st), using a colored font here for a little razzle dazzle:

 

Summary: “UGH-LEEEE–EEEEEE”, west of a line from Detroit to El Paso.

Fortunately these forecasts are not THAT good (it sez so under the map; “use caution for applications–such as for crops” (Hell, that’s why I looked at it!!!! (hahahahaha); in essence, “don’t plant crops based on this forecast.”

But, its the best we can do.  You wouldn’t want to go too far against it.  Don’t plant dryland rice in Nebraska; maybe hedge toward prickly pear.

One aspect about the Southwest is that it takes only a few storm days to clobber these predictions, and those few storm days, as pointed out in the explanatory paragraph in the CPC map above, are largely unforecastable except in the first week ahead.  Great news!

So, with an “El Nina-La Nada” season, such as we have now (not much going on the tropical Pacific Ocean south of us to hang a climate prediction on), doesn’t mean we can’t have decent rains in the next few months as we had last year when droughty projections were also made.  But, as you know, this keyboard is always hopeful, overly so sometimes.

Interestingly, with unusually heavy rains for October on the doorstep for central and northern California, this prediction will take a bit of a hit over the next week.

In the meantime, nice skies!

Dry model prediction WRONG! 0.02 inches falls in Catalina!

It’s great when models falter, and yesterday was one of those times that a human bean can exult.  The U of A model, crunched out on the Beowolf Cluster (I can’t even imagine how powerful such a computer would be with a name like that), said that Catalina would have NO RAIN yesterday, zero, nil, 40-love, zilch, etc. (though there was predicted “model” rain close by).

In fact, in the space of about three minutes, just after 12 noon yesterday, Catalina, right here, received 0.02 inches!!!!  I couldn’t believe how WRONG that model was! It was a tremendous victory for those of us predicting a little rain, like even a trace; those that rebelled against the “king” and won, 2-nil.  If in soccer, it would have been a real drubbing.

Here are the clouds what done it yesterday, small versions of Cumulonimbus clouds that arose from a widespread layer of clouds with shafts of rain that looked like weak versions of our summer thunderstorm shafts:

7:51 AM. A weak shaft of rain falls from a Cumulonimbus sprouting from this overhead layer. The sloping shaft of rain below the cloud indicates both strong wind shear and that the rain drops are pretty modest in size. No cloudburst here.
9:28 AM. Miniature Cumulonimbus cloud with a light rain shower approaches Catalina from the south. Note the lack of dense cauliflower turrets, and wispy, icy tops, no anvils, these obs suggesting weak updrafts. Tops like these yesterday probably only rose to somewhere below 25,000 feet above sea level, and around -20 C (-4 F).  In contrast our summer gully washers usually fall from clouds with tops above 50 KFT.  Still, it was a pretty day overall.  Hope you called in sick to enjoy the first measurable rain in almost a month.

 

4:45 PM. Our last hope for rain arose late in the day when a line of clouds approached from the SW. While no rain shafts were evident upwind of Catalina, this Cumulonimbus and rainshaft was agonizingly close. Why didn’t the clouds show ice and precip upwind (like the sunsetty ones below)? Too shallow, tops didn’t reach above -10 C (14 F) level, a general requirement for ice to form in our clouds here. Temperatures aloft cooled rapidly to the north late yesterday and will today as well, so tops in that direction will be taller and colder than over us. We will again be left with clouds having tops too warm to form ice/rain.

 

5:53 PM. Nice sunset, though, even if the clouds had no ice in them (which would have produced virga).

 

Harangue about those models we love and hate

We desert lifers have a love hate relationship with our mostly superb weather forecasting computers such as at the U of AZ, ones that no longer require us to think when making weather forecasts for the next day or two.  (please see the colloquium by Prof. Cliff Mass in Seattle that pointed out that the NWS was wasting its time putting man-power on forecasts for the next day and beyond;  the computers have largely won that battle.)

Where can we forecasters provide skill?  In the weather right now!  That which occurs in the next few to 12 hours. That’s because, like yesterday, the models don’t know exactly where those showers, ones they might have even predicted, are going to be EXACTLY, and we can fine tune those predictions.  Happens all the time in the chaos of our summer rain season, for example.

But we hate those models like now when they predict dry conditions week after week.  Why can’t a dry forecast day turn up wet, be WRONG?  But they excite us when forecasting rain, even in the fuzzy predictive days one to two weeks ahead.  We know for the most part, such predictions can’t be relied upon, but still we hope they WILL be correct, of course, me in particular (I’m from Seattle and am still adjusting to dry MONTHS).

And here in the desert, most of the rain days predicted in the week to two week range dry up in the models it seems, so there’s always a modicum of disappointment being handed out by them.  We have rain days again today out around the 22nd of Oct, but its not worth mentioning.

 

LA Nada/ “El Nina” update.

The link up there is for a huge technical presentation based on the Climate Prediction Center’s Oct 9 update.  You might be bored by it, or this blog, but then, maybe you wanted to take a nap anyway.

In sum, it looks less and less like an El Nino will form, the Climate Prediction Center losing confidence in their earlier prediction, darn.  But they haven’t bailed altogether.   El Ninos can often produce wetter winters here, so I’m a little bummed out, as you will be if you’re not sleeping, by this update.

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!

————————-

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.

————————————–

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.

———————————-

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.

—————————————

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”).

Parhelia

Parhelia-sun dogs explained here.  We had a couple late yesterday afternoon.  See below.

Models have been running out of rain for Catalina lately for our little weather change that’s coming up.  At one time, we were the epicenter of rain in the mods, more than half an inch was predicted at one time.  Now, they’re calculating only a marginal rain amount as our upper low, now off California FINALLY gets sucked this way out of the Pacific.

Almost as usual, more rain is predicted near the end of the model run, available directly from the NOAA-NCEP source here.

Maybe tomorrow, in our boring spell of weather,  I will have you memorize weather symbols/hieroglyphics, the kind seen on weather maps.

Or maybe I will post a boring rant of some kind on something like how horrible our NOAA climate publications have gotten over the past 20 years or so, having oodles of missing data, such as in the publication, Climatological Data, Arizona.  You wouldn’t believe how bad it is now days!  And THIS, when the study of climate and change is so important!  How can NOAA let this happen??????  (as you can see, just thinking of this has me upset!)  It wasn’t that way when I was growing up when climate studies produced a yawn.

 

4:59 PM on Equestrian Trail Road.
5:00 PM zoom.

5:00 PM also.  For emphasis, I have added an arrow where there is some kind of sun glint in the camera lens; it is NOT a flying saucer, as many of you would like to think so that you could tell the newspapers, family and friends that indeed intelligent ife forms outside of earth exist and they are watching us.

 

The summer 2012 rain season by radar

I was thinking about you and thought maybe you would like to see these charts from NOAA concerning our “not bad” summer rain season, well the past 90 days, July, August and September.  Maybe you’d like to see what the whole State of Arizona got, along with a percent of normal, so here they are.  (It was a bit better here in Catalina than elsewhere around here where we were about two inches above normal (from a 36 year record).

As you can see, quite a few areas got 10-15 inches (brownish centers of yellow areas).  As usual, the above and below normal areas are splotchy, with only a general assessment of usually wet along the Colorado River into southern Nevada (they’ll be talking about this summer for awhile in some of those areas!), and below normal in the eastern 25% of the State.  But, if you look at New Mexico and southern Colorado, you should feel lucky since they really saw a lot of dry days.

Below are maps like the above for the whole US, so you can see how we fit in to the national summer rainfall pattern.  It was great to see those droughty areas we heard so much about at the beginning of summer, say in Texas, come up with above normal rains.

You can make these maps yourself here at the NOAA national site for precip from radar.

I have a dream….

And here it is in the panel below, a pretty wet one, hmmmm, “rainy one”,  for Catalina, one that came out from yesterday’s model run based on the 11 AM AST global data.  The panel below is valid for 11 PM, Thursday October 11th, just 11 days from yesterday.  That blue square over Catalina indicates that this model run calculated that 0.75 to 1.00 inches of rain would fall in the preceding 12 h of that Thursday, the 11th.  How great would that be after this LONG boring and hot dry spell?  I’ve had it with dry!

There is so much rain in this panel for us due to the remnants of another tropical storm whooshing into AZ from the Mexican Pacific south of Baja.  That draw northward to us due to an upper low over southern Cal steering it northward.

I don’t want to talk about the new model run from last night’s later 5 PM AST global data. There must be a mistake of some kind in it not to show any rain here in Catalina in THOSE calculations.  It falls all around us, but not here.

———–

Well, as we know, that Catalina rain in yesterday’s model run, rain that could fall anywhere from the 8-12th, or even on all those days if we’re really lucky, is likely to come and go in these model runs.  The only thing we do know FOR SURE (and this from the “spaghetti” plots), is that rain will be nearby at some point during that period, it will be much cooler, and more typical of fall weather rather than the heat we have now.

The End.

No, update, here at 4:54 AM:  the new model run based on still later data, that from 11 PM AST last night, has rain back over us!   Its not nearly as much as the “dream map.”  Starts on the evening of Wednesday the 10th and goes  through evening of the 11th.

These “manic-depressive” NOAA model runs (ones that can be seen here) are likely to continue, one after another.  So, a bull’s eye, dream rain is still possible.  See lastest spaghetti plot below for confirmation of this assertion.  Veterinarian spaghetti plot interpreters will plainly see what’s ahead around the afternoon of the 11 th of October in the plot below from the 5 PM global data…(you can see the whole series here):

 

Map discussion

The weather ahead

Since we have no weather/clouds to blab about now, it seemed like a good idea to look ahead at our fantasy weather, produced by models, and see what they have for us.  And in these future weather charts, something once again for us here in Arizona to dream about.  These maps below were produced from global data taken at 5 PM AST last evening. Check these rainy maps out, high points annotated like cartoons FYI:

Valid for Tuesday, October 9th at 5 PM AST.
Valid for Wednesday, October 10th at 5 PM AST, 24 h after the first map above. Rain intensifies in Arizona.

And what do we look at to see if this has ANY chance of verifying?

A bunch of spaghetti!

First, the upper level map at 500 millibars that goes with all the rain on that map above, that one valid for the 10th.  This is to see what the upper level configuration is like that is producing this wide area of rain in the SW US.

Aha!   A low center is over the interior of central California at 500 millibars, and moist air (shown in green, of course) has been drawn up into it on its eastern flank, moist air that had been over us (take my word for it).  OK, this looks good.

Valid for the afternoon of Wednesday, October 10th at 5 PM AST.

Below is one of “ensemble” plots created by putting deliberate errors in to the global data to see what happens to the predicted patterns using the real data after small errors are introduced in the initial data–very clever technique.

Will the “perturbed” maps look anything like the ones I that were produced from the real global data taken last night?

Let’s look and make some kind of interpretation that will say “yes” to rain in Arizona, beginning in 9 days (Tuesday the 9th) and continuing off and on for several days!

Valid for Wednesday, October 10th at 5 PM AST

Well, since you’ve been trained in the analysis of these “spaghetti” plots, you will quickly see that it looks pretty damn promising.  It is virtually GUARANTEED that an upper low center will be in the SW US, cut off from the main flow pattern which has angled northward from the Pacific into northern Canada (blue and yellow lines up there).    That yellow circle over central Cal is the actual prediction, and the clustering of blue lines in that same area shows that the “errorful” predictions also see that happening.  So, in that clustering of blue lines, it can be seen that our “low” in the SW is a quite reliable prediction.

Does it guarantee rain here though?  Nope, just that the chances are going to be good in that October 9-12th window.

Also very, very, very, evident in this plot is that the people in the eastern third of the country are going to be very unhappy with all the cold air that they are going to experience before the middle of October.  That weather is, from this plot,  “in the bag.”  Notice how the blue lines cluster in that area and are extruded to the south, indicating that deep cold air will be extruded from polar regions into the eastern US then.  I like the word, “extruded”, BTW.  Sounds great, kind of like an onomatopoeia, like “thunder.”  You can feel it.

Its likely that many low temperature records will be set beginning in about a week in the Plains States and eastern US.  (Remember “air” is “cold”; “temperatures” are low).

An aside:  It will be interesting to see how the media handles this upcoming cold spell.  It has seemed, from this keyboard, that high temperature records get more attention than low ones. We shall see.

The End.