Allergy sufferers beware — an exceptionally large plume of dust from Africa’s Sahara Desert is blowing across the Atlantic Ocean and will make its way to Texas on Friday, causing hazy skies that could mean trouble for people with respiratory problems.
NASA composition maps showed the expansive dust cloud on Thursday stretching from the West African coast to the western Caribbean Sea on a course to Texas.
Meteorologist Weslee Copeland with the Texas Commission on Environment Quality said it will travel through the state over the weekend before it heads north into Oklahoma and the Plains states, depositing dust along the way.
“Usually the coastal areas get the worst of it,” Copeland said. “But as far as Texas is concerned the dust clouds pretty much stay intact as they move across the state.”
It’s not uncommon for African dust to muddy the skies a couple times each summer, as trade winds move further north and take particles from the Sahara into the Gulf of Mexico. The dust clouds can take as long as two weeks to make the long trek across the Atlantic, Copeland said. This weekend’s dust plume is the first to arrive to Texas this year.
Lower Colorado River Authority meteorologist Bob Rose said the impending cloud appears larger than normal, which could mean dust will linger in the air into next week.
“It is fairly rare for it to extend all the way across the Atlantic Ocean,” Texas A&M Climatologist John Nielsen-Gammon said.
The TCEQ, which monitors air quality in the state, considers African dust a pollutant, which will result in decreased air quality. Particles in the air in Austin on Friday and Saturday could measure 2.5 micrometers in size, which according to the Environmental Protection Agency poses a moderate health concern for a very small number of people with respiratory problems. Those people should limit their time outdoors.
The good news is that ground-level ozone, which forms when chemical compounds interact with the sun, is lower on days with African dust, since the air masses originate out of the clean Gulf of Mexico and Atlantic Ocean, Copeland said. Chances for tropical cyclone development are also lower because the dry air mass makes it harder for storms to form, he said.
“We have a lot of dry air accompanying that dust that tends to suppress thunderstorm activity, which is a good thing if you like sunny days in the summer but a bad thing if you need rain,” Nielsen-Gammon said.
A forecast by the National Weather Service shows clear skies the remainder of the week, with no rain chances.
The biggest upshot to the African dust? It makes for quite a stunning evening sunset, Copeland said. The red-orange dust has a way of coloring the sky at night and scattering light from the sun in different ways that can be quite nice to behold.