As you may have seen on social media or on WAFF 48 News, we are expecting a rare scene this weekend; Saharan Dust.
This is all part of the Saharan Air Layer (SAL) which is located between 5,000 to 20,000 feet above the Earth’s surface. This air layer is common from late spring through early fall and frequently makes the 5,000 mile journey across the Atlantic Ocean. This dust comes from the Sahara Dessert in Africa and travels west along the Inter Tropical Convergence Zone (ITCZ) which runs along the Equator. The Trade Winds, which run east to west, pick up this dust from the SAL and carry it over the Atlantic Ocean into the Gulf of Mexico.
While we see some sort of Saharan dust nearly every year, the thing that makes this year’s event so unique is that it will be a much denser/thicker dust layer than years past. In fact, some experts say that this layer has the highest concentrations of dust particles in at least 50 years.
This should not be confused with a dust storm, also called a “haboob,” where you see a wall of dust drastically limiting visibility. Dust storms like that take place at the surface. This dust will be much higher in the atmosphere. What that does means it will just create a milk haze during the day and some beautiful, fiery red sunrises and sunsets during the mornings and evenings. Here is an example from South Florida earlier this week.
Here’s an example of how the dust can impact the atmosphere. This is a comparison photo from Saint Barthélemy, an island in the Caribbean just to the east of Puerto Rico.
Now this is a drastic example, as this is not what it will look like here in North Alabama. By the time the SAL makes it to the Tennessee Valley it will be much more dispersed. The bulk of the dust will move into the Tennessee Valley from the Gulf of Mexico sometime Friday or Saturday and last through Sunday or Monday before it begins to disperse.
While there will be some beautiful sunrises and sunsets because of this phenomenon, it will also create some health issues. This will create some concerns for folks that have asthma or other respiratory issues. This may also impact folks battling the effects and symptoms of COVID-19. If you are sensitive to this kind of allergen then you should limit your time working outdoors this weekend as well as wear masks.
This dust is in a layer of dry air in the upper-levels, which actually limits/inhibits cyclone (hurricanes) and storm development. That will limit our chances at rain development on Friday and Saturday. This is also why the tropics have been relatively quiet over the last week and a half.
If you do get some photos of the beautiful sunrises make sure to share those with us on Twitter and Instagram using the hashtag #WAFF48!