Sky Friday: A Desert Sunset

The skies of southern AZ are nothing if variable and unpredictable.  During my stay in Bisbee, I never ceased to be amazed by the variation in the clouds, both from day to day, and even changes throughout the day.  The same appears to be the case with the Tucson area, although even in the short time I've been here, distinct differences between the Bisbee area and Tucson.  That isn't a surprise, given the conditions under which various types of clouds form and how geographically localized weather can be.

Tucson is situated in a large basin surrounded by mountain ranges in all four directions:  the Santa Catalinas to the north; the Rincons to the east, the Santa Ritas to the south and the much lower Tucson mountains to the west.  Even on the best days, it is covered in human-generated haze and particulates of the  desert kicked up during winds and thermals.  These all have interesting influences on the clouds and sky colors.  Haze, smog and pollution actually result in a more brilliant sunset due to the particles reflecting light in a wider spectrum than with a clear sky.

On Monday, March 22, my second day in Tucson, I was able to head out and get some sunset shots from Saguaro National Park west, a few miles from where my mother lives.  As with sunsets I've shot in the Bisbee area, the clouds show variability when viewed from 360 degrees.

Saguaro National Park makes a beautiful base for the sunsets, both with its mountains and the silhouetted forms of the Sonoran desert flora.

I hope you enjoy this spring sunset from the Sonoran desert:

Late afternoon

These sweeping altostratus, altocumulus and cirrus clouds cover the western sky.

Remodeling

A short period later, and slightly to the south, the colors now show the variation of the different cloud types - smooth and flowing to cobbled and erratic.  The saguaros, however, hold their ground.

Looking East

A double layer of lenticular clouds form over the Catalinas.  Snow is visible on the upper peaks, giving an indication as to their elevation.  Lenticular clouds form when air currents flow over mountains, producing a shear that forms the characteristic shapes.  The lower hills of the Tucson Mtns. are seen in the foreground.  

Sunset 

The peak of this particular sunset.  No bright reds or brilliant pinks or purples as often seen with the Bisbee sunets; these are a range of yellows and oranges.

Twilight in the Desert

This view, slightly northwest, is what the sky looked like after the sun had set.  No fiery colors in the sky tonight.