Weather Words: Saharan Air Layer
It's called the Saharan Air Layer (SAL) and you'll hear meteorologists talk about it quite frequently during hurricane season. SAL is a mass of extremely dry, dusty air that forms over the Sahara Desert and travels westward over the tropical Atlantic Ocean, usually during the late spring through early fall.
The SAL can extend from about 5,000 to 20,000 feet in altitude and stretch across thousands of miles. It's often carried by strong easterly winds known as the African Easterly Jet, which acts like an atmospheric conveyor belt transporting the dust-laden air far from its desert origins.
One of the most striking effects of the Saharan Air Layer is the visible dust it carries across the ocean and sometimes even into the Americas, including the Caribbean and southern U.S. states like Texas and Florida. This dust can lead to hazy skies, vibrant sunrises and sunsets, and degraded air quality.
The most significant role this dusty air can play is its ability to suppress tropical systems. The dry air, strong winds, and warm temperatures hinder the development of tropical storms and hurricanes by limiting thunderstorm formation and creating wind shear. This 'tears apart' tropical systems, so that they don't have much of a fighting chance when faced with the warm, desert dust.
Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.
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