Wild in the West TG weekend ahead; astounding December tropical storm prediction just in

There it is, laid out for you:

Valid Thursday evening,  5 PM AST, November 26th
Valid Thursday evening, Thanksgiving, 5 PM AST, November 26th. SE Arizona is presently on the edge of the action, just windy and mostly dry. But progressing W through N of here, the weather will deteriorate. Likely heavy precip, for example, over this weekend in NW Arizona, especially mountainous areas. Exceptional cold dominates the Pac NW. This weather pattern develops and holds for a few days beginning on Wednesday, November 23rd as a trough from the Pac NW collapses soutward along the Pac Coast, then drifts inland, taking its time before it exits the Great Basin. Will be fascinating to see how the details emerge.

For those who enjoy spaghetti, the above was a real exciting dish to see this morning, one based on last evening’s global data.

Those two people that come here regularly and read these discussions about “Lorenz plots” from the NOAA spaghetti factory,  which I have named  for the MIT weatherman that first proposed “chaos theory”,  Prof. E. N. Lorenz, who noticed that slight changes in initial conditions can make huge difference in stuff later on.  That a “butterfly flapping around in Brazil” can affect a storm in Texas kind of exaggerated paradigm.  But the idea is correct, if ludicrous in that example, one that seems to recur from time to time.

So, in our weather models today,  we alter the initial conditions,  at lot more than a butterfly can do, but still slight ones that are reported by our global data network slightly and see what happens to the forecast of the positions and strengths of highs and lows, and where the jet stream will be  as the model crunches ahead in time. There might be a couple of dozen trials like this (23?)

In the plot shown way below this harangue, only two of the flow lines around 18,000 feet above sea level are shown from the different forecasts that have arisen from these many model runs.  The farther away from the start you get, in general, the more the weather forecasts go to HELL (or do they?)

OK.

Now, where the lines are bunched up is where the model forecast is highly reliable; where they are spread apart a lot indicates cluelessness.

Now if there is an somewhat clearer understanding of this “ball of yarn” plot as one reader put it,  you can see with all the bluish lines gathered together in the western US,  those that are deep inside the jet stream labeled “552”,  that the whole  West will be dominated by a gigantic  trough or cold air by Thanksgiving Day!  Wow.

The red lines, labeled “582”.  are on the periphery of the south and warm side of the jet stream.   Notice how those lines are  “bunched” across the whole Pacific from the troubled fake islands in the South China Sea to Hawaii and eastward into Mexico.

Compare the red lines in the whole Pacific Ocean with the spread in the Atlantic Ocean, the former is indicating more forecast reliability;  the latter less.)

It may not seem like it, but these “Lorenz plots” have been a VERY POWERFUL development in forecasting, only recently permitted when computers became so powerful that we could run our models many times in a short time.  Weather models require the most powerful computers made in the world, those by China, of course,  and not here, which is kind of embarrassing, really1.

All of this is very interesting and indicates a wild Thanksgiving weather weekend! Tell your western friends to watch out!

But, it will be an innervating TG weekend for us cloud and weather-centric folk!

Some rain is indicated in southern AZ due to, hold your breath, the remnants of a tropical storm that filter in Tuesday night and the Wednesday before TG.  Aren’t tropical storms supposed to be gone by now?  Maybe this is the new climate!  Tropical storms all year long!

————————knee-slapper domain————————–

Bursting-out-laughing moment just now after the ludicrous sentence above about tropical storms all year…

The above weather discussion was based on the 00 Z model run, which was, tropically-speaking, pretty staid.

But as I was closing out today’s blog, and smiling at that ludicrous statement about “tropical storms all year long”, I looked at the 06 Z model run, just off the press and when I got to the last few panels, I burst out laughing.  You might, too.

It has a remnant hurricane coming into Arizona on December 2nd, low center still intact as it passes over Phoenix!  This is so funny!

Here are the knee-slapping panels from that 06 z run from  IPS MeteorStar  for your own amusement.  Its REALLY uncanny:

A remnant hurricane hits Baja and comes into Arizona in DECEMBER?  Wow.  No doubt this is  due to that Big Niño down there stirring things up, turning the weather world upside down.

Valid at 11 AM AST, December 1st!
Valid at 11 AM AST, December 1st!

2015111806_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_336

2015111806_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_348
Valid at 11 AM AST DECEMBER 2ND! Note tropical storm center is over PHX, and look at all the rain the model thinks will have fallen in AZ!

BTW, We seem to miss out on any major rains, however, with the TG situation.

The End

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1Those great big Chineses computers can really hack stuff, too!  (Hahaha, just kidding, sort of.)