Dorian, and the Saharan dust that could inhibit Atlantic hurricanes as season approaches its peak

Dorian appears to be heading toward the Florida Coast, but it hasn’t yet grown into a hurricane and probably won’t, the National Hurricane Center says.

That might well have something to do with winds howling off the world’s largest desert.

Sand-dust plumes the size of the contiguous 48 states have been blowing off the Sahara and entering the atmosphere in a prime hurricane-spawning ground off the African coast.

The dry air evidently has a dampening (or drying) effect on would-be hurricanes.

Dorian formed just to the south of one of those plumes, but rammed into it when it turned north, said Jason Dunion, a scientist with the government’s Hurricane Research Division and expert on the so-called Saharan Air Layer, or SAL.

SAL can have “a significant negative impact” on the formation and intensity of tropical storms, he said.

Patches of Saharan dust can reach as far west as Texas, said Dunion, and satellite imagery Tuesday showed significant dry air along Dorian’s projected path.

Those Saharan sand and dust storms occur annually, usually peaking by mid-July. “They get a little smaller and they don’t reach as far west,” he said.

But this year, “they’re still coming off fast and furious.”

Though it is unclear what causes them, potential tropical storms, ironically, might be a factor.

“Mother Nature sets things up in an interesting way,” said Dunion. Hurricanes can have their beginnings in the tropical-storm “nursery” along the southern edge of the Sahara.

Before they bound off the coast of Africa and mature as storms, he said, these disturbances can generate winds that stir up particulate matter from the desert.

The dry particulates can fill the air from 5,000 to 20,000 feet into the atmosphere, an impediment to incipient storms. To grow, hurricanes require warm water and rapidly rising air into a moisture-rich atmosphere.

Dunion said researchers are learning ever more about the dry layers thanks to the improved quality and quantity of satellite imagery.

Said Dunion, “We can see things that we never saw before.”