Going inside the curl, again and again

Its not about hairdressing.  Its about the “curl of the low” and its jet stream configuration, as shown here by here (IPS MeteoStar):

Valid for Wednesday, March 20th, 2013.  Want to see if anyone reads the captions.
Valid for Wednesday, March 20th, 2013. Want to see if anyone reads the captions.

Oh, shoot, this is for a storm and cold blast about 13 days from now! (Secretly, with the storm tomorrow so well predicted at this point by all—might as well show you that it might not be the end of March storms.)

OK, lets try again to get a more timely forecast map:

Oh fer Pete's Sake. This is valid for 256 h from last night, or the morning of March 18th!
Oh fer Pete’s Sake. This is valid for 256 h from last night, or the morning of March 18th!  But we’re in the curl AGAIN!

Oh, shoot, this ones for 256 h or almost 11 days from last night!  What is going on here?

One more try for something relevant, well. its all relevant (suggests we’re in the “trough bowl”:

Finally, valid for 11 AM AST tomorrow morning, this from last night's WRF-GFS run.
Finally, valid for 11 AM AST tomorrow morning, this from last night’s WRF-GFS run.

Maps look kinda similar don’t they? Hence, talk about the “bowl” phenomenon where troughs “remember” where they’ve been like your horse does, and they know where they should be.  There’s a long fair weather gap between the one tomorrow and the ones later;  don’t get fooled by thinking winter’s over.

This last one for tomorrow suggests the rain is either here or imminent at 11 AM AST as the jet core at 500 millibars, is already deployed to the southeast of us by that time.  The timing of all of what happens tomorrow is pretty good for rain amounts since with the chilling air aloft (making it easier for air to rise from near the surface), the cold front will blast across Catalina in the later afternoon.  This means that the little heating that we will get tomorrow, limited by windy conditions and clouds, will work to plump up the Cumulonimbus clouds in the frontal band–oh, yeah, there should be some, and that means what?

Graupel (soft hail)!   Shafts of them, here and there in the frontal band.   The presence of graupel, and it’ll be bashing snowflakes and ice crystals on the way down (the latter can’t get out of the way fast enough) means the clouds will get “plugged in”, electrified,  due to those collisions because they generate electricity and lightning is virtually certain in AZ tomorrow.  Talk about excitement!  Cbs, graupel, lightning, a strong frontal passage, strong winds, and a greater than 100-200 percent chance of measurable rain in Catalina!  It doesn’t get better than that!

This pattern also favors better accumulations of precip here with the winds being more southwesterly to west at cloud levels.  Amounts?  Mod, the very excellent U of AZ mod run indicates Catlania-ites will get around half an inch! I am so excited since this is close to the median amount (0.60 inches) forecast from this microphone two and more days ago!  Something must be wrong!   Here’s the AZ cumulative precip map for Arizona.  Look at all the precip in the State, about an inch and a half of liquid expected on top of Ms. Mt. Lemmon!  This is going to be so good for our drought.

Valid for 3 PM AST on the 9th.  Most of this falls on the 8th, but passing showers add that bit more into the 9th.
Valid for 3 PM AST on the 9th. Most of this falls on the 8th, but passing showers add that bit more into the 9th.

 

Yesterday’s clouds

They were great, such as they were, and before leaving for NM and points east.  Take a look:

6:56 AM.  I wanted to hug these little Cirrus uncinus clouds.  So cute, just trying like anything to make a little snowstorm to water the ground.
6:56 AM. I wanted to hug these little Cirrus uncinus clouds. So cute, just trying like anything to make a little snowstorm to water the ground.  Just look at those long tails!

 

7:47 AM.  Then you got to see a Catalina lenticular cloud.  How nice was that?
7:47 AM. Then you got to see a Catalina lenticular cloud. How nice was that?  Note parhelia on the right.
8:04 AM.  A nice, patterned Altocumulus perlucidus translucidus.
8:04 AM. A nice, patterned Altocumulus perlucidus translucidus.

All in all, I thought it was quite a good day for you.  As usual, thinking about others here.

Today’s clouds

Today we’ll likely see some precursor Cirrus, maybe a flake of Cumulus here and there.  I will predict more clouds, if necessary, as they occur.

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.