Quarter incher (updated; then updated some more with clickable images! You can read stuff now!)

Its not a McDonald’s product, but rather a reference to yesterday’s rain total here in the Sutherland Heights, but maybe there will be some extra blog  “drive bys” of people looking to order a small meal…

Yesterday’s 0.26 inches was only the second day in 39 years that measurable rain has fallen on June 10th (normally reported the following day, today,  at 7 AM 1 novella-sized ).  Rain mainly fell in Sutherland Heights and to the north in this first episode, and later to the southwest through west of us as a big cell came in after 4 PM from the south sporting a huge anvil.

Measurable rain of at least a mm (0.04 inches),  enough to trip the ALERT gauge bucket, did not even fall on the CDO Bridge at Lago, while 1.02 inches fell 1.5 mi west of Charouleau Gap (Cherry Spring ALERT gauge) yesterday.  Nice.

Continuing with interesting information….

The day of this blog was Saturday,  June 11th.

In the past 39  Junes, it has not rained in Catalina on this day.  Check it out with this updated rain occurrences chart with generalities on it, ones that don’t always apply:

The Banner University of Arizona's Weather Department computer model foretells rain in Catlaina beginning just after noon today. If that happens, and I think it will, we will all experience a very rare event! I am really happy for you!
The Banner University of Arizona’s Weather Department computer model foretells rain in Catalina beginning just after noon today. If that happens, and I think it will, we will all experience a very rare event! I am really happy for you!


Yesterday’s clouds (which is now a few days ago, June 10th actually)

12:00 PM. This was an exciting shot for us since it shows that the mid-and upper portions of the Cumulonimbus clouds that are going to form over the Catalinas a bit later, are going to eject out rapidly toward Catalina. Some good rains here can happen in this situation, though not the heaviest ones since those have to fall through the whole body of the cloud rather than from well above the base since evaporation will take a toll on those falling drops once outside the cloud.
12:24 PM. Another cloud builds explosively upward from Mt. Lemmon. Will this one rain?
12:24 PM. Another cloud builds explosively upward from Mt. Lemmon. Will this one rain?
12:23 PM. Top of a weak Cumulonimbus passes directly over Sutherland Heights. A light rain shower is falling from the most distant part where ice formed. The ice was forming as the top went over us, and so the precip fell out after it had gone by, pretty unusual. This was partly because this top had not gotten as high as the one forming over us and downstream from Mt. Lemmon as this photo was taken. Sometimes we get pretty good rain in Catalina from clouds whose mid and upper portions eject out over us from Mt. Lemmon.
12:24 PM. A glaciated portion of the Cumulonimbus top peaks out. No rain was evident from this cloud on top of Mt. Lemmon and whose top passed right over Sutherland Heights. Can you find it? If not, see zoom of this view next.
12:24 PM. An clearly glaciated portion of the top of the Cumulonimbus cloud sitting on Ms. Mt. Sara Lemmon. Pretty exciting to see for us since no shaft was visible at this time, and only the tiniest radar echo was present since the radar was in between sweeps of our area.
1:05 PM. Rain spreads downwind from Samaniego Ridge and is now falling in Sutherland Heights.
1:05 PM. Rain spreads downwind from Samaniego Ridge and is now falling in Sutherland Heights.
12:34 PM. Shaft emerges from Cumulonimbus base onto Samaniego Ridge. Ice aloft was seen before this happened.
7:28 PM. Sun elongates toward the horizon as it sets.
7:50 PM. Looked promising as this TSTM moved toward Catalinaland but faded before it got here.





1Mr. Cloud Maven Person was so excited he forgot that the rain that fell on June 10th will be reported on June 11th.  By convention, the 0.26 inches which fell on the 10th, will be reported as though it had fallen on the 11th.  That’s because it will be the 24 h total ENDING at 7 AM local standard time, the time when most obs are recorded these days.

“These days”?

Yep.  It used to be the most stations, except those having recording gauges as here, as here, which can partition the rain by the exact 24 h it fell in, reported their precip in the late afternoon, 4-6 PM local standard time.   The shift requested shift for cooperative observers like me occurred in I don’t when, maybe 20 years ago.

This shift had an important impact on climate since reading your thermometer, say, at 5 PM in a heat wave, might mean the highest temperature for the following 24 h was almost the same temperature as you had on your prior observational day even if a cold front came through a few hours later on that day and the high temperature on the following day was cold as heck,  the high temperature actually 30 degrees lower.  But the thermometer you reset at 5 PM the prior day will be immersed in those higher temperatures right after you made that ob.  So, when a crazy thing could happen.  The actual high temperature the following day could be 52 F, but the reset thermometer might have 81 F as the high for the whole 24 h following the official ob time.  Got it?  It is confusing, and something that causes headaches in climate studies.

Now, it is thought that the shift to 7 AM obs could lead to a slight amount of cooling since that same effect could happen during a cold spell.  The low temperature of a cold, cold morning might carry over as the coldest temperature for the next 24 h day even if that next day was far warmer.  Glad I’m not too interested in temperature, but rather clouds!   Temperature is too hard, as Homer Simpson might say.

As you can deduce or not, the problem is that cooperative observers only read their instruments once a day as a rule, and the high and low temperatures for a day are averaged to get the average temperature for the whole day.  Its the best we can do since cooperative observers for the National Weather Service are unpaid volunteers, which is redundant.

However, the cooperative observer network for climate data in the US is in collapse these days; not enough money to keep it up and so if you were to check the government publication, “Climatological Data”, mostly comprised of cooperative observations with a sprinkling of official National Weather Service ones, you would find lots and lots of missing reports.  No one seems to care a lot about climate obs these days, though there is a mighty interest in climate models!

Well, we’ve gotten off into quite an informative  harangue here…..


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.