A thin veil of dust from the Sahara Desert is riding the trade winds west, setting the stage for a milky sky and vibrant sunsets across the Gulf Coast. At the same time, the bone-dry air containing this dust is thwarting any attempt by tropical storms to develop and threaten land.
Since the weekend, elevated dust concentrations have been observed at ground level in southern Texas, Louisiana, Mississippi, Alabama and Florida. The quantities have been rather small; springtime pollen outbreaks produce vastly more airborne material. But the transport of dust this far west across the entire Atlantic is remarkable, and the gulf can expect extra colorful sunsets, to boot.
“Typically every summer you’re going to get Sahara dust that gets carried over at least part of the way,” said Eric Bunker, a meteorologist at the National Weather Service office in Tallahassee. The dust is able to reach the United States a couple of times each season.
The plume is most concentrated from Cabo Verde to Puerto Rico and Cuba, pooling in the Gulf of Mexico with the fringes approaching land. Some has even been slingshot around a high-pressure system anchored over the Florida peninsula, transported all the way up to Atlanta.
Houston, meanwhile, is at the nose of the dusty conveyor belt. Much of the dust has been “scavenged” from the air after heavy rain and severe storms worked through overnight. The squall line will wash any remnant dust out of the air over much of Southeast Texas, central/southern Louisiana, and southern Mississippi on Monday afternoon before the band starts to fizzle. The result? You might encounter a wafer-thin film of gritty dust garnishing your car Tuesday.
Farther east, there’s no widespread rain to rinse the air. That will keep the dust up in the sky. If you’re in southern Alabama, Georgia or Florida, odds are the sky will look a little bit milky or with a slight tan tinge to it Monday. And by Monday night, that dust will be responsible for boosting fiery-red sunsets.
“If we’re going to have more particles in the air from the dust, it will help refract the light around sunset,” Bunker explained. “It will help to give us a much deeper red sunset in the evening.”
In high doses, Saharan dust can be dangerous. The extremely fine particulates can pose a hazard to those with sensitive lungs, frequently prompting the National Weather Service to issue air-quality alerts. This time around, the aerosol’s concentration is low enough to stay below any threshold for concern.
In fact, the arrival of Saharan dust might be good news for Gulf Coast residents beleaguered by a destructive 2018 hurricane season. The reason? Saharan dust tends to quell Atlantic hurricane activity.
It’s not the dust that does it per se but, rather, that the dust is a tracer embedded in a layer of desert air. Having air that dry in the middle atmosphere puts a damper on any attempts for a tropical cyclone to form. Moreover, the minuscule particles can “seed” rain as moisture rises in the atmosphere, causing it to fall to the ground prematurely. Tropical waves that become entangled with Saharan dust plumes have often been observed to fizzle.
So enjoy it! Afternoon thunderstorm chances are low Monday across much of the Gulf Coast, making for ideal viewing. An evening picnic, recliner chair, good book, a cool beverage and crimson-colored sunset? That’s a home run forecast any day.