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:


3:42 PM. Mostly Altocumulus here, some slight virga.
3:52 PM. Same view, 10 min later. Can you see what’s jetting at you?







The End.