"The North American Monsoon" and "Significant Weather Reports"

It's mid-July/early-August, and that means it's time once again to talk about the North American Monsoon. 

The word “monsoon” comes from the Arabic word mausim, meaning season. Basically, it describes a seasonal shift in winds over a region, usually accompanied by a dramatic increase in precipitation. Many of us are familiar with the Indian-Asian monsoon, which brings heavy rains during the summer months over large parts of India and Southeast Asia. Although these rains often produce major flooding, they are vital to agriculture and the economy. Because so much of the world's population lives in this region, a delayed or reduced rainfall season can have a devastating effect on the livelihood of a significant fraction of the world's population.

Many other parts of the world experience monsoons, including North America. Our North American monsoon (also known as the Mexican monsoon) typically occurs between July and September and is relatively small compared to the Asian monsoon. However, in parts of NW Mexico, over 50% of the annual rainfall comes in this 3-month period. The rains provide a critical source of replenishment for the water resources of Mexico and the Southwest United States.

CoCoRaHS volunteers can play an important role and possibly save lives by submitting a real-time "Significant Weather Report" when heavy precipitation occurs during flooding monsoonal rains. Check out our “How to Measure Heavy Rainfall” animation.

To learn more about the North American Monsoon, please take a look at this very informative page put together by the National Weather Service: “Monsoon.” Also, you can watch Chris Castro’s WxTalk Webinar on the “North American Monsoon,” which offers a lot of great information.