Bulimic Cumulus clouds, filled with portent, disappoint

Why would such skinny, towering clouds be filled with thundery, gushing portent?  Its really hard for a cloud to be tall and skinny.  Why?  Because too much dry air comes in as it rises, both from the tops and sides, and if that air is  dry, it can’t go far without evaporating.  Too, the drop in temperature with height has to be larger than normal for clouds like yesterday’s to shoot up to well beyond the level where ice can form (glaciate).  But they did off and on all day.  Mt. Lemmon functioned as a smokestack for Cumulus and even skinny Cumulonimbus, clouds all during the late morning and into late afternoon.   There was some thunder here as ONE got big enough to rain that bit toward Charoleau Gap.  So, you do get to record a TSTM (thunderstorm) in your log book.  No rain fell here.

If you missed those bulimic clouds, here’s yesterday’s movie from the U of AZ.  If you watch that time lapse, you will see some of the tallest turrets shooting up awfully fast; I thought they were rising about fast, at times, anyway, as any turrets I have seen in these movies, a marker for how rapidly the air cooled with height yesterday.

Also, here are a few shots of those skinny clouds from this angle here Catalinaland.

 

11:34 AM.
11:36 AM. Skinny over yonder as well!  Look at the behemoth behind it!
1:26 PM. “Smokestack Lemmon”, the old folk singer, still puffin’.  Wonder if Sara smoked?

 

 

 

 

 

 

 

1:50 PM. This next puff showing more “calories”… Uh-oh.  Head coming off, chopped off by dry air in the middle.  Dammital.
2:03 PM. The gruesome sight of a chopped off head of a Cumulus cloud that reached the ice-forming level. At least it had ice in it this time, showing the the puffs were getting taller.
2:43 PM. Best one of the day, a Cumulonimbus cloud, was producing thunder at this time. A slight, transparent rainshaft was evident on Cat Mountains to the left of this shot. Notice that head of this cloud drifted away from the root or body. That means the rain falling out is going to pretty light, maybe as here, a hundredth or two.

 

 

 

 

 

 

 

 

 

 

OK, quiting visual cloud displays here.  You’ve seen enough disappointing clouds, ones that did not live up to their potential like so many of us.

You would have thought massive clusters of Cumulonimbus clouds were about to roll in, spawned over the Rincon Mountains or from the high terrain near Pie Town, NM, rolling westward to pummel the townlet of Catalina again.  Some of our more gigantic area storms have been preceded by morning “long tall sallys” like these.

But no.

Looking at today:

The boys in the weather club, like Bob and Mike, were talkin’ good storms today based on their very great and decades-long experience.  I, too, am riding the Bob-Mike wave.

Way out ahead; major rain joy, maybe…

I am more excited about the longer term view, one in which when it gets here, will remember what I said with enthusiasm now.  Remember our logo, one just like the big TEEVEE stations have:

“RIght or wrong, you heard it here FIRST! Live!”

What “first”?

Tropical storm remnant has been probably unreliably, but hopefully, forecast to come into southern Arizona in 192 h or so.  Could be worse; what if it was a forecast that was 360 h from now?

Here it is, courtesy of those folks at IPS Meteostar who have rendered the 00 Z (think Olympics Time Zone) time maps for us.  Here’s the low, shown on the first map, on Baja coast.  The next map shows that the ENTIRE remnant has moved into AZ!  Could be great.

What gives this storm a better chance of getting here than some?  The upper level steering is set up to draw tropical storms northward should they drift too far northwest, like a bug getting caught in a spider web; the spider then hauling the bug to its hiding place.  Gee, I never thought I would write about spiders here, but there it is; it just kind of popped out.

But, you ask, how do we KNOW, have any CLUE, that the steering, as by an upper level trough, is going to be properly placed to draw tropical storms northward so that they get caught up like a bug in a spider web which after being caught in the web, the spider comes down and takes it back to its hiding place.  I really liked that metaphor. We are like that place where the spider is hiding!

Of course, you say, we go to the NOAA spaghetti factory and try to discern how likely it is that a trough will be along the West Coast, positioned to draw storms up thisaway.

The last image is a spaghetti plot of trough contours using what be called, “the bad balloon” approach.  Hard to imagine, but the starting points for the model is deliberately altered a bit just to see how wild a few of the contours get.  The wilder they get, the less reliable a longer term forecast is.

Valid for August 15 at 5 PM AST. Note all the green, denoting rain that fell in the preceeding 6 h.

 



NOAA “spaghetti plot” valid for the SAME time as the first map, 5 PM AST, August 15th. Shows that a trough along the West Coast is virtually assured. But the “devil”, the storm here, is in the details. While it is a necessary condition, it is not sufficient, since the flow might not exactly draw a tropical storm right to ME. Oops, “us.”

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.