EarthSky Facebook friends in Florida are reporting hazy skies and strange sunsets due to a cloud of dust from Africa that left the continent earlier this week and traveled across the Atlantic Ocean. The dust arrived in parts of South Florida on July 19, 2012. Its effects will be seen mostly in the southern part of the state, and possibly along the west-central and southwest Florida coast (between Tarpon Springs to the north, and Naples to the south, including the Tampa Bay Area), known to Floridians as the Suncoast, according to Florida Suncoast TV station WWSB.
This is the first large dust storm from Africa to arrive in Florida this year. The satellite imagery below shows the dust leaving Florida on July 16, 2012 and heading out to sea.
The dust came from North Africa’s Sahara Desert, the world’s third-largest desert. In satellite imagery, you can see large clouds of dust coming off the African coast heading toward Florida. It’s common for dust to blow from westward from Africa, but you need just the right meteorological conditions – a mix of thunderstorm updrafts and upper level winds, according to WWSB – to send the dust into the east to west flow of the Intertropical Convergance Zone (ITCZ), which is the area encircling the earth near the equator where winds originating in the Northern and Southern Hemispheres come together. These winds send the dust hurtling toward Florida.
Bottom line: Dust from northern Africa’s Sahara Desert arrived in southern and southwestern Florida yesterday (July 19, 2012). Floridians are seeing hazy skies and unusual sunsets. This is the first large dust storm from Africa to arrive in Florida this year.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.