Trough bowl relocates to Arizona

Since the Big Bowl is just ahead, featuring our Seattle Seahawks, a team that played their games right near the University of Washington where I worked, it seemed like a good title, one that ordinary, football-loving peoples could identify with.  But, of course, I am talking about “trough bowling” and the inclement weather that goes with them, right here in Arizona, not in New Jersey.

Models are foreseeing a spell of upper level troughs collecting in the SW US in the next week.   In the map below from the NOAA “spaghetti factory“,  you will see a great example of the best chance for a halfway decent rain in AZ as these several troughs march through, including one today (but too far north).  All we get today is clouds, mostly middle and high ones, too high above us to rain on us, then later in the day, lower ones like Stratocumulus, but with tops too warm to form ice crystals, necessary for rain here in old Arizony even though it may look pretty gray at times.

Back to the maps….

In the map below, the red, yellow and gray lines all bulge southward toward the Equator in our area.  The wind at this level (500 millybars, around 18,000 feet above sea level) travels along the lines going toward the SE off’n Cal, then bend back to the NE over Baja.

The air tends to sink and dry out in flow going to the SE, but tends to rise and moisten as it bends back to the NE.  So, as troughs come and go, with the SW winds ahead of them pass by, there’s a chance for rain each time one goes by.

The third one that passes by, later on Thursday, February 6th, gives us the best chance for widespread rains, as foreseen for AZ by last night’s 5 PM AST model run.

How great would that be?

If you don’t believe me that widespread rains are forecast for AZ, you’ve given up on rain here after weeks of drought, I’ve added a map from last night’s model run.  Its OK.  I’m a weather forecaster and there’s a certain degree of incredulity, an aura really, that goes along with this occupation. We get used to it, kind of like economic forecasters do.

You can go here to poke around the NOAA model.

Valid February 6 at 5 PM AST.  I've annotated it so you will know where Arizona is.  Its shocking to me that I have to keep putting arrows on  maps showing where Arizona is to my readers.
Valid February 6 at 5 PM AST. I’ve annotated it so you will know where Arizona is. Its shocking to me that I have to keep putting arrows on maps showing where Arizona is to my readers.
Valid at 2 PM, February 7th, 2014.
Valid at 2 PM AST, Friday, February 7th, 2014.  The green areas denote where the computer model thinks rain has fallen in the previous THREE hours.  There are several maps like this after this one for 2 PM, ones that extend the AZ rain  into early on the 8th.  Who knows at this point, but maybe half an inch could fall here in Catalinaland.  Hoping so.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mods are grim after this storm passes on the 7th, with the jet stream staying north of us, maybe for the rest of February, and that means chances of rain are nil.  No jet, no rain.

Oops, I forgot to show you where Arizona is….here’s that same map again.

Same prog, valid for 2 PM AST, Friday, February 7th, 2014.  Recall that this storm has been predicted, more or less, for about two weeks.
Same prog, valid for 2 PM AST, Friday, February 7th, 2014. Recall that this storm has been predicted, more or less, for about two weeks, as has the pattern change.

The first real chance of light rains here is just ahead, that on late on MONDAY!  Looks like only a tenth of an incher, though, right now.

BTW, poppies in bloom (!) are being reported by hikers here in the Catalina area. Wonder if this has happened before in January?

Looking ahead to rain and other weather mischief in the days ahead.

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.