Sunday, June 28, 2020

Winds blow massive Saharan dust cloud into US airspace

Updated Jun. 28, 2020 12:07 AM









Dust from the Sahara Desert that has been pouring off the western coast of Africa and into the Atlantic has effectively put the Atlantic hurricane season on pause, with the exception of short-lived Tropical Storm Dolly, which formed on Tuesday, June 23, in the North Atlantic. The dust is largely impacting the Gulf Coast, but could push northward into the airspace above a few other states farther inland.

The robust plume of dust, which satellite imagery showed had reached into U.S. airspace by Friday, has been felt by many across the Caribbean, where it left behind a thin coating on the ground in some areas. The sky turned hazy over the U.S. Virgin Islands, Puerto Rico and Cuba, and visibility was drastically reduced in some areas. By Friday morning, the air quality in Galveston, Texas, where AccuWeather's Bill Waddell is stationed, had plunged from "excellent" on Thursday evening to "unhealthy."

Dusty skies were also observed in Panama City Beach on Friday morning, according to video posted on social media, and dust appeared to be hanging low in the skies over the Houston skyline, a photo posted on social media by Sergio Chapa showed.

"A quick glance out the window, it's easy to confuse it for fog," Chapa, a 44-year-old Houston resident told AccuWeather, adding that the haze looked like fog but with, "a slight brown tint."

"This is much different from ozone action days, but not quite like a forest fire," Chapa said. "I wear glasses and I was wearing a face mask. My eyes are fine, but even with the mask, my throat is irritating after talking around for about 30 minutes in the dust storm."

Dust is often pushed off the African coast during the early stages of Atlantic hurricane season, but the vastness of this episode has raised eyebrows. Some experts have described the plume as the most significant event in the past 50 years and even referred to it as a “Godzilla dust cloud,” according to The Associated Press.

The cloud is part of what's known as the Saharan Air Layer (SAL), which usually occupies a 2- to- 2.5-mile-thick layer of the atmosphere, with a base starting about 1 mile above the surface, according to the National Oceanic and Atmospheric Administration (NOAA).

AccuWeather meteorologists have been tracking dust emerging from the Africa coast since April, but there has been an uptick in activity since around June 14. Dust is most commonly observed over the Atlantic into July before it becomes less of an issue later in the hurricane season. AccuWeather's top hurricane expert Dan Kottlowski said the African Easterly Jet has been stronger than normal and this has produced more dust.

"Certainly the dust episodes in the Caribbean have been more robust than normal due to the active jet," Kottlowski said.

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Just this past week, the dust floated across the Caribbean into the southern Gulf of Mexico, and now forecasters say it'll hover over the Southern states through Sunday.

The dust is forecast to be primarily concentrated over Gulf Coast states, from Louisiana to Florida, but some could expand farther north into Alabama, Georgia, and Tennessee, Kottlowski said. He added that the forecast does not call for high concentrations of dust to play a role in the overall weather pattern across the northeastern U.S. Some dust could "barely" reach into southern Virginia, Kottlowski said. 

“Dust, like any pollutant, can find its way farther north over time and it’s possible some dust could work into the Great Lakes this week but it probably would not be very noticeable. A storm system forming in Canada over the weekend will move southeast into Maine early this week and bring a wind flow out of Canada and not up from the tropics,” Kottlowski said.

Dust particles can produce vibrant sunsets and sunrises, but if there is too much of an accumulation, then those sunsets or sunrises can turn out dull. Dust is usually most noticeable when the skies are cloud-free, according to Kottlowski. The cloud cover combined with the haziness from dust obscured the sunrise in Galveston on Friday morning, Waddell reported.

Air quality levels could also drop from moderate to unhealthy over southern and eastern Texas, according to Plume Labs. Those with respiratory issues are being urged to limit the amount of time they spend outdoors. AccuWeather and Plume Labs have a partnership that allows users to monitor the realtime air quality in a given location from the AccuWeather website or mobile app.

People watch the sunset while a cloud of Sahara dust hangs in the air in Havana on Wednesday, June 24, 2020. The massive cloud of dust was blanketing the Caribbean as it heads to the United States. (AP Photo / Ramon Espinosa)

Kottlowski said there is a second large area of dust over the Atlantic, likely to move into the eastern Caribbean on Sunday, but it seems less impressive than the first batch of dust currently invading the U.S. The second round of dust is likely to dissipate faster, thanks in part due to stronger winds forcing it westward. However, it will still bring a “considerable” amount of dust to the Gulf of Mexico early this week which will result in hazy conditions and milky-looking skies.

The presence of dust across the Gulf of Mexico, depending on its exact location, may inhibit tropical development into the early part of July.

Longer range forecasts show an easing in the amount of dust entering the atmosphere over the week as the African Easterly Jet, which is responsible for triggering the potent storms that kick up the dust, is forecast to relax a bit, according to Kottlowski.

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Additional reporting by Bill Waddell.

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