What is a monsoon? Here’s the definition as phenomenon hits California
The word monsoon comes from the Arabic word “mausim,” which means season. This is a fitting way to describe the period when rainstorms are more prevalent in the desert.
"A monsoon is a large-scale change in overall weather pattern," explained Marvin Percha, meteorologist at the National Weather Service.
The monsoon season starts approximately in June and continues through September. Since 2008, the established dates from the National Weather Service are June 15 through Sept. 30.
These dates only suggest a higher possibility of storms, so don't be confused if rainy weather doesn't align perfectly with those start and end dates.
Drenching rainstorms: Death Valley National Park roadway buried in record-breaking rains
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What causes a monsoon?
A couple of factors are at play in order to create the kind of conditions for rain. The two big ones are the direction of the wind and moisture and daytime heating.
A shift in wind direction from the south to the southeast occurs in the summer. The moisture from the Pacific Ocean and the Gulf of Mexico creates streams to the north. Combine this with the heat from the day in California, which creates rising air or low pressure, and the conditions are set for monsoon storms.
Drenching rainstorms: Death Valley National Park roadway buried in record-breaking rains
This article originally appeared on Arizona Republic: What is monsoon weather? How phenomenon can impact California
