Lemmon drop; 2.28 inches!

We accumulated just 0.01 inches of rain here from those overhanging anvil clouds from thunderstorms centered on top of Ms. Mt. Lemmon early yesterday afternoon but they drenched Ms. Lemmon with 2.28 inches!   Details from the Pima County ALERT rain gauges can be found here.  The next highest amount was on Samaniego Ridge with a nice 0.79 inches.  Both good.

You may have noticed something odd, too, the thunder from those cells was continuous for a long time while Lemmon was getting pounded, quite remarkable,  indicating, as you would guess, highly electrified clouds, unusually so.

The last time I experienced continuous thunder without break was in Oklahoma City during the El Reno tornado-producing complex of Cumulonimbus clouds,  ones with huge mammatus formations that just ERUPTED from the overhanging, approaching anvil cloud repeatedly. An example of that dramatic OKC scene, FYI:

May 31, 2013, 3:34 PM above ASA Stadium, Oklahoma City.
May 31, 2013, 3:34 PM above ASA Stadium, Oklahoma City.  Thunder from in-cloud lightning, as here yesterday, was continuous, not the least break, as the rain approached and tornado sirens went off.  Yep, Mr. cloud-maven person was there and took this shot.  The former company team, the Washington Huskies, had made it to the WCWS. and me and the missus used to go to the Husky games in Seattle.

Oddly, like that OKC situation, where there was almost no cloud-to-ground lightning as the storm approached, and not so much during the 5-7 inches of rain that fell there that night.   Neither was there much C-G LTG around here yesterday with OUR continuous thunder;  I saw not ONE cloud to ground strike in the several thunderstorms which developed on top of Ms. Lemmon,  nor  from the continuous thunder-producing  cell toward Charoleau Gap around 7 PM.   Here are views of our contrasting thunderstorm and overhang from that at OKC looking toward  the Cat Mountains.   Below that, the remarkable-to-me, anyway, the continuously thundering cell with a modest rainshaft toward the Gap in the evening hours:

12:34 PM, soon after nearly continuous thunder began on from the cells on top of Ms. Lemmon.
12:34 PM, soon after nearly continuous thunder began from the Cumulonimbus that erupted on top of Ms. Lemmon.
7:03 PM, looking toward Charoleau Gap and a moderate-sized Cumulonimbus emitting continuous thunder.
7:03 PM, looking toward Charoleau Gap at a moderate-sized Cumulonimbus ALSO emitting continuous thunder! No cloud-to- ground strikes were seen over about a half hour’s time.  And the thunder ended abruptly,  like a light bulb that had been unplugged.   That was odd, too, since usually LTG tapers off as the conditions producing it slowly change (well, over minutes, anyway.)

I really expected to see some rogue cloud-to-ground strokes coming out of that overhang over Catalina yesterday (middle photo), as often happens here, dangerous ones because they can be quite removed from the rainshaft and so you don’t expect them.

Have only seen one or two days like yesterday before, absent cloud to ground strikes but a lot of electricity up there  in Catalina over the past five summers.  So if you thought it was an unusual day, you were right.

Today

More showers and TSTMS are expected in the later afternoon and into the nighttime hours according to the U of AZ model run from 11 PM AST last evening.  Still hasn’t finished crunching numbers, but goes through tomorrow morning.  Again, the flow is from an easterly direction and so the early bombardment of Mt. Lemmon should have us in the trailing overhand again until evening when cells are likely to form away from the mountains today.

A real odditiy is that upper level low from back East (Virginia) that is headed to Catalina land!  You can see its progress over the past few days here from the U of WA map makers here–you’ll need a big pipe to see all 64 of these frames in a reasonable time.,  Here from San Francisco State, these 500 mb maps, starting with the low over West VIrginia and SE Ohio, ending this morning with the low now over the Texas-Oklahoma border!  Amazing.

July 12 at 5 AM AST. Low too be here forms over Ohio and West Virginia! Oh, my, this is so funny.
July 12 at 5 AM AST. Low too be here forms over Ohio and West Virginia! Oh, my, this is so funny.
5 PM AST, July 14th. The SAME low is now moving into Texas toward ME!
5 PM AST, July 14th. The SAME low is now moving from OK into Texas and toward US!
Valid for July 18th at 5 PM AST. Remnant of low moves into SE AZ.
Valid for July 18th at 5 PM AST. Remnant of low moves into SE AZ.

So if something like this happens, we’ll have a DISTURBANCE to cluster our Cumulonimbus clouds into real monsters, ones bigger in area, and ones that last longer, maybe make up some rain deficits around here.

Of course, with such an odd track, lots can go wrong, but its something to keep in mind.

The End.

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.