Creamy mammatus precedes overnight thunderation

Thin Cirrostratus overspread the sky at dinner time from the east, thickening into Altostratus cumulonimbogenitus mammatus (you can breath now), toward the Catalina Mountains and in the direction of Oracle.  What a gorgeous sight this was!

While the storms that spawned this icy blob were mostly dead by this time, undercutting Altocumulus castellanus below the mammatus formation (barely visible in the photo below) gave hope that the day was not done as far as rain was concerned.  And it wasn’t.

Round about midnight, the wind and one of the more intense lightning shows of the summer crept over the Catalinas and into Catalina, sparks flying.  Strikes too close for CM to feel comfortable on the front porch in metal lawn furniture.

Sutherland Heights was watered with 0.18 inches, an OK amount, enough to revive some of the wilting desert weeds of summer.  The Cat Mountains, not surprisingly, got the most.  Ms. Sara Lemmon got 1.02 inches, Sam Peak, 0.83 inches. Hope they weren’t having an astronomy show at the Sky Center!

You can see the list of Pima County gauges here.  LTGICCCCG1 still out there to the distant SSW at this hour, and major rains are still in progress in western Arizona, all good.  (Those low lying areas of western Arizona such as along the Colorado River,  have a “bi-modal” peak frequency of late evening and early morning rains, btw.  Not much happens in the middle of the day to mid-afternoon out there.)

No clouds during the day yesterday, even over Mt. Lemmon, was a surprise, and is rare in my seventh summer here, and is a testimony to how dry the air was aloft over us even with some humidity near the surface.  Things quickly changed during the night, and this morning, we’ve got it all, significant humidity at the ground all the way up to Cirrus levels.  Perhaps due to the low starting temperatures associated with the rains in the area, the U of AZ mod doesn’t think Cumulonimbus clouds will form over our mountains until late afternoon into the evening hours.

In any case, should be a great day visually; lots going on.  Thinning clouds this morning, then the rise of the Cumulus, and we hope, as the mod projects, another blast of rain in the evening and early nighttime hours.

7:26 PM.
7:26 PM.



6:00 AM.  In case you missed it just now, this beauty.
6:00 AM. In case you missed it just now, this beauty.














The Weather WAY ahead

The NOAA spaghetti factory still is not showing patterns that are fruitful for generous rains overall in the next 15 days or so.  So, anything we get should be considered quite a blessing during this time.  Another giant trough is going to affect the East Coast and Midwest (the last one, a couple of weeks ago, brought the coldest July day in the 140 year history of Memphis records where for the first time the high temperature did not reach 70 F in July!  Wow.)  Those east of the Rockies may well wonder in the times ahead, what happened to summer?  Of course, those cool temperatures might well be welcomed in late July and August, but the circulation pattern that brings them is also not so great for summer rains here.  Oh, well, hoping for the best.

Sincerely, your CM.

1Weather text for “Lightning in the cloud, cloud-to-cloud, and cloud-to-ground.”  A weather report amended with this comment, LTGICCCCG, was always one of the most exciting that you could see reported from a station, especially if you lived in lightning-deprived areas like California and Washington as did CM.

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.