A giant cloud of dust that formed over the Sahara Desert is now blowing westward over the Atlantic Ocean and toward North America. It is expected to put a lid on hurricane development during the first part of August, a time when hurricane development usually begins to ramp up quickly.
While Saharan dust blowing out into the Atlantic is nothing new, this particular Saharan Air Layer is unusually dry and dusty.
The dusty, dry air acts to inhibit hurricane development in two ways. First, the dust filters out sunlight. The less sunlight available to heat up the Atlantic Ocean's surface, the cooler the ocean temperature will be. A cooler ocean means hurricane formation is less likely.
Second, the Saharan air layer coming off Africa is hot and dry. It floats over the warm, moist surface layer of air in the Atlantic and acts as a stabilizing layer that inhibits thunderstorm -- and subsequent hurricane -- formation.
The dust layer will traverse the Atlantic over the next several days.