The perfect rain

The “perfect storm”?  Well, maybe the perfect rain, and it kept giving fro several hours yesterday after our best model said it should end yesterday before 11 AM.  And what a nice rain!  1.18 inches total here in Sutherland Heights, as measured by a CoCoRahs plastic 4 inch gauge.  (You might consider getting one, btw, or one from the U of A’s rainlog.org)

Went down to the CDO and Sutherland Washes to see what was up after seeing the gargantuan 4.96 inch total on Ms. Lemmon, and the 3.62 inches at the Samaniego Peak gauge.  Below is the resul for the Sutherland, both were the same, nary a drop in them:

8:15 AM. Looking upstream in the Sutherland Wash at the back gate of Catalina State Park. Stratocumulus clouds provide a dank cloudscape.
8:15 AM. Looking upstream in the Sutherland Wash at the back gate of Catalina State Park.  I could hardly believe that there was no flow with so much rain having fallen in Catalinas!  But it was good in a sense; all that rain mostly soaked in.

 

6:37 AM. A photo of drizzle falling from Stratus/Stratocumulus clouds. Hope you got out and jumped around in our rare drizzle occurrence. Big hat, no bicycle works in drizzle, too, keeping it off your glasses.
6:37 AM. A photo of drizzle falling from Stratocumulus clouds. Hope you got out and jumped around in our rare drizzle occurrence. Big hat, no bicycle,  works in drizzle, too, the tiny drops won’t get on your glasses. Note how uniform the fuzziness is toward Catalina/Oro Valley, only gradually thickens to the left.  Took about 2 h to get a hundredth when this was going on.

 

7:23 AM. Drizzle drops as seen by your car's windshield after about 1 sec at 1 mph. Note how close together they are. The tiny drops and how close together they are is what differentiates true drizzle from the phony labeling we sometimes get from our TEEVEEs by semi-pro meteorologists. Sorry to bang on them again, but REALLY, folks, they should know better.
7:23 AM. Drizzle drops as seen by your car’s windshield after about 1 sec at 1 mph. Note how close together they are. The tiny drops and how close together they are is what differentiates true drizzle from the phony labeling of spares large drops as “drizzle” we sometimes get from our TEEVEEs by semi-pro meteorologists. Sorry to bang on them again, but REALLY, folks, they should know better.  Sure, I’m a drizzle-head, but it really does matter since its a whole different process that produces drizzle compared to sparse large drops.  Sorry, too, for another mini-harangue on this, but REALLY folks, we should know the difference!  Feeling better now, got that out.

 

8:02 AM. Heading down to the Sutherland Wash with temperatures and dewpoints in the mid-60s, there really was a feel for being on the wet side of the Hawaiian Islands, maybe above Hilo, HI, at 3,000 feet elevation.
8:02 AM. Heading down to the Sutherland Wash on Golder Ranch Drive with temperatures and dewpoints in the mid-60s, there really was a feel for being on the wet side of the Hawaiian Islands, maybe above Hilo, HI, at 3,000 feet elevation, except for the dead grasses.
10:20 AM. One of the many dramatic scenes yestserday, this one looking toward the Charouleau Gap NE of Catalina.
10:20 AM. One of the many dramatic scenes yestserday, this one looking toward the Charouleau Gap NE of Catalina.
10:19 AM. While it was nice to see all the water glinting off the rocks on the side of Samaniego Ridge, a deeply troubling aspect was the amount of aerosol that had moved in suddenly it seemed, evident in the crespuscular rays. How could it be this dirty so soon? Seems like a weather oxymoron after such a long period of rain. Also, one wondered if this aerosol loading would stop the warm rain process by providing too many, and smaller droplets in our clouds.
10:19 AM. While it was nice to see all the water glinting off the rocks on the side of Samaniego Ridge, a deeply troubling aspect was the amount of aerosol that had moved in suddenly it seemed, evident in the crespuscular rays. How could it be this dirty so soon? Seems like a weather oxymoron after such a long period of rain. Also, one wondered if this aerosol loading would stop the warm rain process by providing too many, and smaller droplets in our clouds.  Fortunately, that did not happen, and what appeared to be warm rain events, or ice formation at relatively high temperatures in our clouds, also requiring extra large cloud droplets,  for the most part, continued intermittently into mid-afternoon.

 

10:32 AM. Close up of aerosols and sun glints on wet rocks.
10:32 AM. Close up of aerosols and sun glints on wet rocks.

 

12:23 PM. Glimpse of ice-forming top. Types of crystals visible here? Needles and hollow sheaths because the top temperature was likely equal to or warmer than -10 C (14 F) and cooler than -4 C, and that is the temperature range that those crystals form under when there is water saturation, as there is in the Cumulus turret before it glaciates.
12:23 PM. Glimpse of ice-forming top (smooth region above crinkly top). Types of crystals visible here?
Needles and hollow sheaths because the top temperature was likely equal to or warmer than -10 C (14 F) and cooler than -4 C, and that is the temperature range that those crystals form under when there is water saturation, as there is in a Cumulus turret before it glaciates.  OK, a lot of hand waving, but that’s what I think and I am here mainly to tell you what to think, too.

 

5:36 PM. Day ended quietly with a little, but pretty scruff of orographic Stratocumulus, maybe castellanus, on Sam Ridge.
5:36 PM. The day ended quietly with a little, but pretty scruff of orographic Stratocumulus castellanus on Sam Ridge, the clouds mashed down by the subsiding air at the rear of our little trough that went by yesterday afternoon.

 

The weather WAY ahead, too far ahead to even speculate about:

NOAA spaghetti plots still suggesting a pretty good chance of rain here around the 23-25th of this month.  Nothing before then.

 

The End, after some improper speculation.

Author: 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.