This part of the hurricane season is typically very quiet and for good reason. It is during this portion of the year that we see the strongest of what are called “SAL” outbreaks. SAL stands for Saharan Air Layer and it is a the equivalent to spraying Raid on insects: it kills hurricanes.
The reason is simple. The low to mid level dry air originates from the Sahara and North Africa. Often times the SAL is populated with fine dust and other suspended particles such as sand. This acts to squash any chances of tropical convection and moves generally westward, eventually reaching the Caribbean and even the United States.
During especially strong SAL outbreaks that end up moving in to the Southeast, the result is often an incredible sunset for a few days as the dust filters out just enough sunlight to create a brilliant deep orange to red glow. It is also not uncommon for dust to collect on car windshields.
The good thing about SAL is that it means no hurricanes. With a strong layer of dry, stable air, there is absolutely no chance of development in the tropical Atlantic; not until the environment moistens up. This usually begins to happen around the second week of August. If the SAL outbreaks continue past that time period, then we may start to wonder about whether or not there will be much of a hurricane season left. However, I would bet that this is yet another typical July SAL event and a month from now, we’ll be talking about the potential for development across the same region that is so hostile right now.
Until then, enjoy the quiet, and perhaps the brilliant sunsets, courtesy of SAL.