Monsoonal Moisture Finally Making Its Way Into the Southwest
Christy Bowen
5 hours agoIt has been a relatively docile North American monsoon season up until recently. Here is a look at how this annual weather pattern has been impacting the Desert Southwest this summer.
Understanding the Specifics of the North American Monsoon Season
Every summer, the southwestern U.S. braces for the arrival of the North American monsoon season. This weather pattern brings a surge of moisture to the normally dry desert landscape, sparking flash flooding, wildfires, and other dangers.
It has been a quiet monsoon season up until recently. The action has picked up in recent weeks. For instance, Phoenix Sky Harbor International Airport recorded 0.18 of an inch of rain on September 4. Las Vegas got in on the moisture machine the next few days.
The Phoenix metro area typically sees 2.43 inches of rain throughout the monsoon season, compared to about 7 inches over the course of the entire year. Other historical averages during the monsoon season include 5.69 inches in Tucson, 4.48 inches in Albuquerque, and 5.27 inches in Las Vegas.
While the big story during the monsoon season is the arrival of rain, the pattern is actually triggered by the annual shift in the wind direction. The monsoon season is not limited to the Desert Southwest. Places such as India experience an even more pronounced flow of monsoonal moisture during the summer months.
The term "monsoon" has Arabic roots, coming from the word "season." The seasonal pattern associated with the change in wind flow is driven by the difference between the temperatures on land and the readings in the ocean.
The monsoonal moisture in North America originates from the Gulf of California and the tropical areas of the Pacific. Populated urban areas that get caught up in the moisture-rich air flowing northward include Phoenix, Albuquerque, and Las Vegas. The stream of moisture typically begins in the northwestern corner of Mexico in June before spreading into the U.S. Southwest in July. The moisture typically turns off by the end of September.