WATCH: Monsoonal Storms Bring Haboob To Phoenix Area
Right before the afternoon commute home was about to fire up in Phoenix Thursday afternoon, visibility plummeted as sand and dirt filled the air. An enormous dust storm, also known as a haboob, brought in a wall of dust to the city. Winds gusted up to 40 mph, which kicked up dust as high as 5,000 feet, reducing visibility to less than a quarter of a mile. The storms – fueled by monsoonal moisture – downed trees, caused flooding and left thousands without power.
During the summer months in Arizona, we experience monsoon season. A monsoon is a large scale weather patter. The winds across the southwest U.S. shift from their usual western direction to a southeastern wind. This causes the winds to pull in moisture, often from the Gulf of Mexico, that afternoon convection taps into to produce heavy downpours and storms. A monsoon day is considered when the dew point (moisture content in the atmosphere) is greater than 55°. A warm humid atmosphere is what thunderstorms feed off of, therefore during the summer months, storms build with rapid speed. As thunderstorms build, they pull air up into the sky – this is known as the updraft. When the updraft/clouds can no longer support the weight of the moisture aloft we see the rain start to fall. As the rain dumps, air surges to the ground and outward, known as the downdraft. These downdraft winds often race out in front of the storm, which we sometimes call a gust front. These strong gust fronts have the ability to kick up the dry desert sand and dirt, causing these massive dust storms.
According to the National Weather Service in Phoenix, AZ the average ending day for monsoon season is September 13th. With roughly half a month to go, this may not be the last dust storm the Phoenix area encounters this season.
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For WeatherNation: Meteorologist, Tracey Anthony