In an area impacted by just about every type of weather event, from miniscule dust devils to far-reaching tropical storms, weather watchers typically focus on one aspect of Tucson's variegated climate: the Arizona Monsoon. Located far in the Sonoran Desert, Tucson is ruled in summer by intense sun. During the early part of each summer, the sun's heat bears down through dry air; predominant westerly winds carry little moisture after cresting numerous mountain ranges en route from the cold Pacific to Tucson. But around late June to early July of each summer, this wind flow changes from westerly to predominantly southerly and southeasterly—the “Monsoon”—due primarily to seasonal shifts in the jet stream. Unlike the westerly airflow, however, monsoon winds carry moisture—large quantities of moisture.
Weatherwise Contributing Editor ED DARACK is an independent writer and photographer. His latest book is Victory Point, published by The Penguin Group; visit his Web site at www.darack.com.