“Groundhog Day” all over again

If you mainly focus on going to movies about weathermen, you will remember this classic along with Steve Martin’s “LA Story.”   Bill Murray, the weatherman, is condemned to live the same day over and over again until he gets it right. Since yesterday was a near repeat in many respects to the failed rain day of Monday, this seemed like an appropriate title.

1.   OK, morning:  some really nice Altocumulus castellanus (miniature Cumulus clouds with flat bottoms) and “floccus”–raggedy bottoms1. These indicate a nice drop in temperature as you go upward in the “middle-levels” (around 10-15 Kft above the ground) and that in turn helps the formation of thunderstorms.

2.  Clouds topping Mt. Sara Lemmon again indicating a grade of  “juicy” moisture hereabouts.

3.  Very early thunderstorm, first thunder heard a 10:40 AM in a mountainous Cb N of the Cat Mountains (shown below in its, “Cumulonimbus calvus” stage;  top is ice, but is not yet CLEARLY fibrous, striated).

Seemingly all is in place for large thunderstorms to be scattered hither and thither later in the day, rumbling and banging around, scaring cats and dogs with lightning sabres, blinding rain, puddles in the road, TEEVEES out of whack, missing your favorite show, “TV party tonight2” canceled.  OK, enough dramatics and songs2.

But it didn’t happen did it?  Why not?

One of those very circulations foretold in the numerical models slipped over us yesterday during the day, and as these circulations do (you can see it here in this long “water vapor” loop)-you’ll need a broadband connection to see this.   You’ll see a miniature low spin into SE AZ from Sonora, MX, late on the 11th-early yesterday morning.  The darker area rearward of this circulation represents horrible drier air in the mid-levels especially.    The whole point of this loop is to show that drier air moved in and desiccated the otherwise growing Cumulus clouds following the passage of this micro low above us.  The very raggedy tops of our afternoon Cumulus clouds was an indicator of this extremely dry air that did not allow them to explode upward with the afternoon’s heating.

You could see this happening since,  in a homogeneous air mass, there would be no full blown Cumulonimbus clouds just to the north semi-circle of Catalina, and only weak Cumulus with ragged tops spearing that dry air at the same time in the southern semi-circle from Catalina.   I started to get depressed.   Something was going wrong, the air was getting too dry upwind.

Still, the there were enough Cumulus and Stratocumulus around at sunset to produce another memorable sunset.  Maybe that’s reward enough.

The End.



1distinguishing between the two is a bit silly IMO.

2Who can forget the Black Flag tune, “TV Party Tonight”?  “We’re gonna have a TV party tonight!  All right!”