Plenty of late November rain ahead…in model; a sunrise beauty

In case you missed it, yesterday’s sunrise:

6:52 AM.  Altostratus with mammatus underlit by rising sun.
6:52 AM. Altostratus with modest downward hanging mammatus1 bulges under lit by rising sun above the Catalina Mountains.  Altocumulus clouds are in the background.  Was a magnificent sight.
6:57 AM.  Mammatus protuberances more evident here, and quite lovely.
6:57 AM. Mammatus protuberances more evident here, and quite lovely I thought.  I seem drawn to mammatus formations.












The weather way ahead

Well, the WRF-GOOFUS model has lots of rain for us again as November closes out, with the model rain amounts foretold in November for Catalina now totaling over two inches, or about twice normal. Its been great model month of rain for us. Below the latest rains foretold, beginning on the 27th, continuing into the 29th.  Here from IPS MeteoStar, these renderings from our best model, based on last evening’s global obs taken at 5 PM AST:

27th 2013111400_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_336
Valid at 5 PM, Wednesday, November 27th.
28th 2013111400_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_348
Vallid on Thursday, November 28th at 5 AM AST.
28th 5 pm 2013111400_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_360
Valid at 5 pm November 28th. Green areas denote areas where the model has calculated that rain has occurred during the prior 12 h.
27th 2013111400_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_336
Valid at 5 AM AST Friday, November 29th.

There is some evidence from the NOAA spaghetti factory that churns out those spaghetti plots that a big change happens in the last week of November, so rain at the end of the month, two weeks from now,  is not out of the question.   This rain pattern results from a stagnant upper low SW of us which you can see here.

What about the weather immediately ahead?

Global pattern shifting like mad today due to what we call, “discontinuous retrogression” caused by low cutting off out of the jet stream in the central Pacific.  Troughs/ridges jump westward almost overnight when this happens.  Highs disappear overnight as is happening right now over the whole West!  Very exciting, except in this case, while a trough blossoms overnight replacing a ridge in the West, its amplitude (how far south the jet stream in the trough gets) doesn’t seem to be enough to provide us with rain here in Catalina now.  Remember that winter rain here is nearly ALWAYS associated with a jet (at 500 mb) to the south of us.

This drastic change in pattern often only lasts a couple of days, too, before reverting to “same old same old” as we had, fair and warm.  I wanna cuss here.

The foretold development of a trough in mid-month in the West was a huge, and strong signal, you may recall, in our “Lorenz  plots” (I am hoping this name catches on; he deserves it), those balls of yarn I show every so often.  So the trough and cold air getting here to SE AZ has been “in the bag” for more than 10 days in advance,  according to those strange plots.

However, the rain here in the actual model runs has come and gone in them as mid-month approaches, and lately, there ain’t been nothin’ here.  At most, a few hundredths it would now seem, and most likely, nil.

1Gender-specific naming cloud variety convention: if male, as in the case of the writer, this cloud formation is deemed,  “Altostratus mammatus”;  if female, the proper name would be “Altostratus testicularis.”  Its part of an adjustment similar to the one when only female names were used for hurricanes, and doing that, it was felt,  lent a kind of stereotype to female behavior/character.  So, male names for hurricanes were introduced by NOAA in the 1970s to “even the score”.

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.