Massing bases, smiling faces

Yesterday’s surprise thunderstorm, rolling off the Catalinas, provided relief with 0.22 inches here.  More rain tables/maps here and here. This sight in the first shot,  showing it in the formation stage yesterday, was cause for joy:

2:12 PM

Due to global warming-induced extra heat over the past few days here, as all extra heat must be automatically assigned (go here to a critical commentary on recent claims like mine above by a still-employed University of Washington Atmo Sci. prof.–wonder how long he’ll last?) combined with a break in the summer rains, our grasses, amaranth, pig weed and such were looking pretty stressed out; wilted, turning yellow due to global warming.   One felt helpless to see the green of summer fading so fast due to global warming.  (Want to make sure I am on the RIGHT side of this issue, you can’t be too careful these days about what you say in this domain; who might be watching.)

Then, after a near miss to the north yesterday around noon, an initially small thunderstorm that dumped on Saddlebrooke, moved off to the NW, multiplied,  and became a real giant on the north side of the Tortolita Mountains, this new, large cloud base (at left) began forming over the Catalinas upwind of us. Time for hope.

Rain was already falling out of the downwind leaning upper portions of the cloud (arrow), shown in the second shot.  You might recall that rain that falls out like this is not going to be what it could be, all that it could be.

Y?
Imagine dropping a cup of water out of that cloud where the bottom is (arrow), to drift away from the main discussion for a second.  What will happen?  Since the humidity must be less than 100 % all the way to the ground after it leaves the cloud, a lot of that water from that cup will evaporate.  If you could capture the water that originally came out of that cup, it might be 10% of what came out.

How high was that “base” that’s not really a base but an overhang (above arrow in second shot)?  Probably at the freezing level, or about 12,000 feet above us.  So, if you’re storm chasing, and want to collect the most rain, avoid rain from overhangs!

The next shot shows where you want to be to get the most rain, and in a hurry.   Those dark bases managed to hold together and keep reforming as rain fell on the Catalinas.  A new strand of rain has overcome the updraft associated with new dark bases, and is beginning to fall out this side of Samaniego Ridge.  An arrow has been added to point out this new rain streamer.  It reaches near the ground beyond the dead yucca stalk in the foreground.   This is where you want to be to collect the most rain, should you be trying to do so.

Y?

This time, pouring out a cup of water at the same height as in overhang rain, but inside the cloud, several thousand feet above the bottom, means that there will be no evaporation, and MORE IMPORTANTLY, the cup of water will grow in volume until near the very bottom because the falling drops will bump into and collect floating cloud drops that got in the way.  So, if you could collect that water somehow, there would be more of it than what you dropped originally.  So, those rain streamers, forming high in the cloud, are doing the same thing, pulling water out of the cloud on the way down, growing in amount.

This was a heartening sight since this new shaft, and the movement rate of the storm as a whole, meant that it would reach ME and Catalina in general) before it dissipated.  As it turned out, probably another such shaft dropped right on top of us, judging by the low visibility in the intense rain.  Air, rudely pushed out of the way by all that water, created winds to estimated 50-60 mph for a brief time, followed by an almost instantaneous reversal to 5-10 mph.  That reversal was really something, as was as the lightning strike back behind me about 100 yards.

Today?

Expected to be dry. End of story.  I really don’t enjoy talking much about dry air.

What about Hector-Ernesto, that schizophrenic tropical storm that has come all the way into the eastern Pacific from a birth place in the West Indies, home of calypso music, some weeks ago?

The Canadians think Hector-Ernesto is going to end up as a big rain producer southern Cal, with some rain enhancement here as well. The USA! models think its going to drift north and die before getting much past Baja, where it drifts off to the west. Due to a rain bias, I am only showing the Canadian model result with a tropical storm approaching San Diego and a huge crescent of rain over the Southwest, including over ME (oops, I mean us).