Some clouds; excessive excitement over model flip flops (web crawlers: not about shoes or girls wearing them) for late November

Here they are:

12:18 PM. Altostratus translucidus (sun’s position is visible).
2:34 PM. More Altocumulus opacus with virga. Large clearing approaches from the west.
3:46 PM. Patch of Altocumulus translucidus perlucidus (thin, with a honey-combed pattern)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Today?  More pretty clouds.

The weather way ahead, like on November 29th

Just after I was asserting from this typewriter that the big storm, the Great Wet Hope in late November, was surely bogus, out popped another wet forecast for AZ n the model run crunching global data from 11 AM AST yesterday.   Here it is below, first panel.   You MAY remember that the nice early rains that we had in November last year were associated with a similar pattern of an upper low center near San Diego.

What to think of this “outlier” forecast, one NOT supported in the ensemble of spaghetti plots (model runs where small errors are deliberately input to see how those runs change from the ones based on the actual data).  There very little support for panel 1 in those “perturbed” runs, but there it was again, a big AZ rain!

Well, its still unlikely, but the chance of it actually happening are now much improved.  Something out there is causing the model to come up with a good rain in AZ at the end of the month.  I did not think I would see any rain again in AZ in any more model runs.

And, sure enough, the model run based on data just 6 h later than the one shown in the first panel, took it away again!  See the second map below and look at the astonishing differences over Arizona and the Southwest overall!

I won’t show it, but the “perturbed with errors” model runs that we look for to discern credibility in the longer term forecasts like these, STILL does not support much of a chance for a rain to be realized on the 29th.

But, that second appearance of an “outlier” in another model run….hmmmmmmm.   Will be watching for a return;  you start to get a feeling that it might well be seen again.

As I finish this blog blurb, the 11 PM global data should have been crunched by now, and will look to see if there is yet another huge change (well, there are always large changes, but here, I’m talkin’ for us!)  Will let you know in about 2 minutes….  Stand by, generating new web window now…..

Oh, my gosh!  Its changed again (3rd panel) to a huge West Coast troughy situation, completely different than the run at 5 PM AST last evening with the big ridge over us (bulge to the north).   I have to post this latest map, again for late on November 29th.  The situation you see in the third panel leads to another big rain forecast in AZ, though a couple of days later, early December!  This is so great!  Compare the second and third maps.

Now, you can really start to put some credibility in the supposed “outlier” forecast and, as a discerning meteorologist, say to the spaghetti plots with their little deliberate errors, “Go to HELL!  You’re missing something big out there with those puny errors you start with.”

Calming down now, well, you can’t cast the thought of warm dry weather (seond panel) for late November out yet, but something IS being missed out there, which makes this an exciting period–just to see what happens.  Though an admitted precipofile, at least here in AZ, not so much in SEA, I am putting my mental marbles on the trough in the West depictions now.  Just a hunch.

The End.

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.