View of Saharan Dust Layer over the tropical Atlantic, from space. (CIMSS)

Africa sneezed, and the tropical Atlantic is choking.

An intense, sprawling dust storm exited the African west coast earlier this week, effectively squashing any tropical storm formation in adjacent Atlantic waters for days to come.

Look at this animation of the ejection of the dust storm, courtesy the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (hat tip: Jonathan Erdman, The Weather Channel):

Animation of Saharan Dust Layer (SAL) Monday through Wednesday (CIMSS)

Over the Atlantic ocean, the storm has formed a highly concentrated layer of atmospheric dust, known as the SAL (Saharan Air Layer). It is characterized by extremely dry air, which acts to suffocate the development of thunderstorms and the organization of tropical weather systems.

Here’s a high resolution view of the SAL, from NASA’s Terra satellite:

Terra satellite high resolution image of dust storm exiting African coast Monday evening (NASA)

NOAA’s Environmental Visualization Laboratory, using an aerosol (a fancy word for fine particle) model, projects the movement of this dust layer over the next several days:

By the weekend, the SAL spans from the coast of Africa to Puerto Rico. It’s no coincidence weather forecast models simulate no tropical storm development in this window.

Jeff Masters at Weather Underground has a more technical overview of the SAL, for those interested: Massive African Dust Storm Cooling Atlantic Hurricane Odds for Early August

And here’s a more elementary synopsis: