“Front Light”; compare to Bud Light

Front will roar across like a mouse, not a lion, as hoped for a few days ago.  Not too many rain “calories” in it.  Measurable rain will still occur, starting sometime between 9 AM and 10 AM AST–oops. raining now at 7:10 AM!   Check out U of AZ model for rain timing.   First drops fall here in that model output (from 11 PM AST last night), between 8 AM and 9 AM.  The frontal band, such as it is, is almost here!  However, the model rain tends to arrive  a little fast here,  though not always.  FYI, be on guard.

C-M is holding firm with a minimum of 0.15 inches today, but previous foretold possible top of 0.80 inches a few days ago is out of the question.  Will be happy with 0.25 inches at my house.  Since I am also measuring the rain as well as forecasting it, I have a feeling things will turn out fine.

There will be a nice temperature drop, windshift, and simultaneous rise in pressure as the cold front goes by–it’ll be fun for you to watch the barometer today and see the minute the front goes by as higher pressure begins to squash down on you.

Rain might reach briefly moderate intensity (defined by official weatherfolk as 0.10 to 0.30 inches per hour).  It would be great if it lasted an hour at that rate, but it likely won’t.  Its moving pretty fast, and it doesn’t seem like more than 2 h of rain can occur today.  Look for a nice clearing in the afternoon, and a COOL evening.

Drive south if you want to avoid rain today.  Jet core (in the middle levels, 500 millibars, 18, 000 feet above sea level) is almost overhead, and just to south, and that core is almost a black-white discriminator of rain here in the cool season.  So, we’re on the edge of the precip today.  More to the north;  less to the south.

Some clouds for you

1O:55 AM, December 11.  Thought you should see this nice line of Ac castellanus and floccus underneath Cirrus spissatus.
1O:55 AM, December 11. Thought you should see this nice line of Ac castellanus and floccus underneath Cirrus spissatus.
7:02 AM. Sunrise.
7:02 AM. Sunrise.
12:32 PM.  Wind picking up at the ground and aloft.  Note tiny Ac lenticular with Cu fractus clouds.
12:32 PM. Wind picking up at the ground and aloft. Note tiny Ac lenticular with Cu fractus clouds.
3:14 PM. The high cloud shield from the storm encroaches. Could call this either Cirrus spissatus or Altostratus translucidus.
3:14 PM. The high cloud shield from the storm encroaches. Could call this either Cirrus spissatus or Altostratus translucidus.
5:22 PM.  Now we're talkin' Altostratus with underlit mammatus and fine virga.
5:22 PM. Now we’re talkin’ Altostratus with underlit mammatus and fine virga.  So pretty.
5:29 PM.  A late "bloom", not really expected.  Shows that there was a clear slot far beyond the horizon.  Had to pull off by the Refuse Waste station on Oracle to get this.  I hope you're happy.
5:29 PM. A late “bloom”, not really expected. Shows that there was a clear slot far beyond the horizon. Had to pull off by the Refuse Waste station on Oracle to get this. I hope you’re happy.

The weather ahead and WAY ahead

Speaking of bowls, and let’s face it, with only a 100 or so we could use a few more1; we here in all of Arizona are in the “Trough Bowl” now.

This means that troughs (storms and cold fronts)  that barge into the West Coast will gravitate to Arizona instead of bypassing us and they will do that over and over again.    Being in the Trough Bowl is great fun! Lots of weather excitement for weather-centric folk like yours truly.    When you’re in the Trough Bowl, the weather is “unsettled”;  is NEVER really nice (if you like sun and warmth) for very long because a new front/trough is barreling in at you.

So, while today might be a little disappointing,  we will have many chances to get the “real thing”, i.e., a behemoth of a trough among the many that affect us in the weeks ahead.

In the longer view, a behemoth of a trough for the Great SW has just popped out of the models1 just last night in the 11 PM AST run! Gander this monster truck trough for AZ.  Where’s that monster truck event announcer, we need him now!

Valid for 11 PM AST, Christmas Day!  Wow.  Can't really take this at face value that far out, but if it did happen, likely would be snow in the Catalina area, and horsey would likely need a blanket after it went by.  Will keep you informed periodically about this as the days go by.
Valid for 11 PM AST, Christmas Day! Wow. Can’t really take this at face value that far out, but if it did happen, likely would be snow in the Catalina area, and horsey would likely need a blanket after it went by. Will keep you informed periodically about this as the days go by.

OK, enough weather “calories” for you today.   Hope you’re excited like me.

The End

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1Furthermore, why don’t we have bowls for women’s teams, what happened to Title IX there, maybe Beach or Sand Football? )

2As rendered by IPS MeteoStar, which is about to go from “free” to “fee” in January.  Dang.

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.