The Twelve…rain drops in Catalina, that is

Well, maybe there were about 27, but anyway….not very many; still,  those drops were to be treasured after not seeing a single  “hydrometeor” display in SE AZ in so–ooooo LONG A TIME!


PG-13 advisory; DRIZZLE is discussed

I have to warn you at this point.  That rain event yesterday WAS NOT DRIZZLE!!!!!!!!!!!!!!!!!!!!!!!!!!!  I will be ROYALLY PO-ed if I hear someone in my social network or a TEEVEE weather presenter say that it “drizzled” yesterday!

Why make a BIG THING out of the correct type of precipitation?

I have to tell you a true story (well, I don’t have to, but I am going to anyway) about the importance of drizzle (i. e., fine, close together drops that appear to FLOAT in the air).   This event happened during my cloud seeding “vigilante” adventures (see Publications for samples).   A well-known professor of cloud seeding in a foreign country asked me to leave his office and never come back after I told him it had been “drizzling” outside, “10s per liter” in the air.

Drizzle is a profound indicator of cloud structure overhead, and the presence of drizzle falling from the clouds in that professor’s region’s meant his numerous reports of how clouds were, ripe for cloud seeding,  were in substantial error.   So you can understand why a report of true “drizzle” would naturally be upsetting to that professor.  Man, am I digressing here!  Yikes.  My apologies. (BTW, those reports WERE in error, confirmed by aircraft years later!   (Spiking football now, with a proper amount of decorum, of course!)


OK, back on task….

With the sky full of low (“boundary layer”) clouds by mid-day (f you’ve forgotten, that was yesterday, May 10th, 2011) and with RW— in the air  (“triple minus”, extremely light rain showers) by 1:30 PM,  with gusty winds,  temperatures in the mid-60s, it turned out to be quite a “storm.”  It just as well could have been but a mostly sunny day with just a scattered Cumulus clouds here and there the way some models were “telling it.”

Here’s a pictorial on how it went, from a Catalina, AZ, perspective:

1) 09:29 AM, itty bitty Cumulus (Cumulus “fractus”) starting to appear,

2) 12:03 PM, larger Cumulus growing up into Cumulus “mediocris” beyond Tortolita Mountains on the horizon,

3) 12:29 PM, virga and rain visible to the NW horizon!  Now I am getting apoplectic since the best models in the world did not have this precipitation over thataway!   But there it is, bigger than watermelons.  The models have to be really red-faced about this! Not everything in the world is predetermined by numerical models; you can  say things that might be right and those models are WRONG!  Just like in the 1970s when a lot people thought global cooling was underway and that’s where we were headed!  But they were WRONG!  Who were those clowns anyway?! (hahaha, sort of).

4) 1:25 PM.  Now where was I before all that excitement?  Oh, yeah.  Here’s some ice for you.  See the frizzy top parts of this cloud in the center of this photo above the dead tree that the birds like to sit in?  Well, them’s ice crystals, and likely snowflakes that have formed in that medium-sized Cumulus cloud (above the dead tree) and its in the upwind direction.  Behind that is more ice and precip falling from a wide area of a Cumulus-Stratocumulus complex.



Quiz.  How cold does the top of THAT cloud have to be to look like that (have that much ice in it, probably a few per liter to maybe 10 or so, not a tremendous amount but significant)?  Well, with bases as cold as they were, near freezing by this time of day at around 7, 000 feet above the ground or 10, 000 feet above sea level, around -15 C (or about 5 F).  Amaze your friends with cloud trivia like this!  Well, maybe not.


5)  1:25 PM.  Here it is, a band of precipitating clouds overhead.  Now the ONLY question remaining, as you gaze upwind at Twin Peaks clearly visible through the precip and virga is, how much will there be?  None? Or as much as a “trace”?   Measurable is out of the question,  looking at this scene below the clouds.  Most of the visibility degradation is due to dusty air, not precip.  Darn.   (Amaze your friends with skills like this!  Well, maybe not.)

6) 3:03 PM.   The End is Near

7) 7:06 PM.  Nice sunset with traces of Cirrus and Ac len on the horizon, driblets from a storm striking the Pac NW.  Isn’t there always a storm striking the Pac NW? I digress again.

Man, I could go on about the weather maps of yesterday, but will quit here.

The end.






















































If you REALLY want to see how it went, take a look at the U of A time lapse video here.