It’s monsoon time in the desert. We’ve actually been in “monsoon season” for a few weeks, but last evening was the first evidence of it in my area. Fundamentally, monsoon is linked more to a shift in winds than precipitation, as evidenced by shrieking dust storms followed by three fat drops of rain. In fact, the name “monsoon” is derived from the Arabic word “mausim” which means “season” or “wind-shift”.
The Arizona Monsoon is a well-defined meteorological event (technically called a meteorological “singularity”) that occurs during the summer throughout the southwest portion of North America. During the winter time, the primary wind flow in Arizona is from the west or northwest—from California and Nevada. As we move into the summer, the winds shift to a southerly or southeasterly direction. Moisture streams northward from the Pacific Ocean and the Gulf of Mexico. This shift produces a radical change in moisture conditions statewide.
Such a change, together with daytime heating, is the key to the Arizona monsoon. This wind shift is the result of two meteorological changes:
- The movement northward from winter to summer of the huge upper air subtropical high pressure cells, specifically the so-called Bermuda High (H).
- In addition, the intense heating of the desert creates rising air and surface low pressure (called a thermal low) in the Mohave (L).
These two features combine to create strong southerly flow over Arizona. The southerly winds push moisture north-ward from Mexico, although the exact source region for the moisture of the Arizona monsoon is unknown.
Now that you’ve had your meteorological lesson for the day, let me just tell you that a monsoon storm blows like crazy — usually in the evening just after you’ve lit the barbeque for those two-inch thick steaks that have been marinating all day, a lovely wine is waiting to be poured, the salad is high and healthy with good salady things and you’ve just set the patio table. Yep. That’s the moment when a wall of dust slams through your back yard, upending table and chairs and tipping your beautiful salad and wine all over the place.
That’s what monsoon is all about.
Which is exactly why I’m taking a morning flight tomorrow, rather than the more convenient evening flight. Those pesky monsoon storms normally come in the late afternoon or evening. Flying in and out of Phoenix is bumpy at best with its thermals and updrafts or downdrafts or sidedrafts or whichever way those drafts come. It’s always bumpy over Phoenix. But flying through a storm would force me to drink heavily while strapped into a tiny seat in an upright and locked position. To avoid that whole messy scene altogether, I just fly in the calm of the morning. It’s nice. No nervous laughter in the cabin. People calmly sipping their morning coffee. Business people with laptops, readying themselves for their business stuff. People reading serenely, picking out items from the Sky Mall. Kids playing nicely in their seats.
I’ll be gone just a few days. Out Friday and back on Tuesday. I’m traveling light, so I’ll most likely not take my laptop — unless I decide there’s room and I don’t mind the extra weight — I never know what I’ll do until the last moment. In the meantime, be well and stay safe.
When I return, our next lesson will be about crickets and why my kitchen is covered in butcher paper and blue painter’s tape.