Sun and Altocumulus clouds combine to provide a colorful sunrise and a sunset on the same day! Rain on tap!

“Rain on tap” does not  refer to a microbrew, for those who’ve accidentally stumbled onto this site.

Our nice sunrise and sunset, featuring supercooled1  Altocumulus clouds:

7:22 AM.
7:26 AM.
7:29 AM. Ice crystals trail down from this region of cloud cover toward the north. Was it hers or ours? This Altocu layer was at -15°C (about 4°F), cold enough for some natural ice, but not as prolific as this. The fact that the ice does not trail downward much indicates the crystals in this virga were really small, also suggesting a non-natural event since an aircraft can produce thousands per liter of ice crystals, none of which can grow to very large sizes. Maybe ours?
9:20 AM. Well, what’s a day in Arizona with supercooled Altocumulus without an ice canal caused by an aircraft. So, they were occurring yesterday.  We don’t see them much in the summer because the Altocumulus clouds are warmer.


4:36 PM. Our steady diet of Altocumulus yesterday is topped here by a veil of CIrrostratus, all leading one to expect a colorful sunset.
5:52 PM. So pretty again….


5:52 PM. Wider view of the same scene.


Rain on tap?  Oh, yeah….finally.  One forecaster friend is predicting 0.5 inches!  How nice would that be?  The rain will likely begin toward midnight–check it here from our nice U of AZ Weather Department.

Looking for more rain in AZ after mid-month, toward the 20th.

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.