“Saharan dust” is a familiar term to anyone who has lived in the southeastern United States. It’s a big player during hurricane season. However, if you haven’t spent much time in that part of the country, this may be the first time you’re hearing the term as a thick layer of dust moves through the South.
This “sand storm” isn’t really anything unusual. It’s just more dust than usual. Saharan dust comes to the Caribbean, Gulf and SE Coast by way of Africa’s west coast. The prevailing wind, the African Easterlies, blow west and carry air from that region of the world into the Caribbean and Gulf. Within the easterlies “waves” form. These can turn into tropical disturbances, depressions and hurricanes. The environment in this part of the N Atlantic is perfect for hurricane development. They thrive on warm, moist air and the warmer ocean provides that.
That’s where Saharan dust comes in. Just as dust storms form in the United States, we also see them in Africa… but on a larger scale. The Sahara Desert is very large and very dry. When storms develop there strong outflow winds can kick up powerful dust storms that lift dust into the atmosphere. This dust is picked up by the Easterlies and carried into the N Atlantic. This is NOT good for hurricanes. These air masses are very dry, leading to an unfavorable environment for hurricane development. Typically they lead to some haze and increased dust pollution in the air, but nothing major.
The difference in the current situation is the volume of dust. Frequent and large dust storms have pushed a lot of Saharan dust into the atmosphere. That is currently impacting Florida and will spread into Texas and through the South through the weekend, and even into parts of the Midwest, clearing by early next week. These areas can expect to see darker skies and poor air quality. The weather pattern will keep the dust out of S Colorado. High pressure sits over the SE and will pull the dust in a clockwise circulation AWAY from Colorado.