Saharan dust cloud heading toward South Florida, US


While summer thunderstorms pound South Florida, a very concentrated area of Saharan dust is coming all the way from Africa. The northern Caribbean islands have already been dealing with Saharan dust with very hazy skies. The dust should arrive sometime on Thursday and last until next Monday. The dust is carried over 10,000 kilometers (6,000 miles) from North Africa,  by the same atmospheric waves that bring tropical storms to US.  The dust layer typically remains 1,5 km (5,000-6,000 feet) above the ground.

florida sahara dust

Every year dust sweeps across the ocean along the trade winds and slips into the skies above Florida and many Caribbean nations. There have been several instances of this dust in South Florida already this year. Dust settles into its own layer of Saharan air and stabilizes the atmosphere, reducing the amount of clouds and trapping the surface-based air into the atmosphere’s lower levels. Higher temperatures are predicted as the dense Saharan layer insulates the atmosphere and suspends the mixing associated with South Florida’s usual sea breeze.

Particularly thick layers in the past have increased the chances of breathing problems for those with respiratory issues and dust spots on motor vehicles after brief rain showers.

This is one of the largest concentration of dust for years making it that far west across the Atlantic Ocean. Usually dust starts to dissipate as it reaches the western Atlantic. Saharan dust is a limiting factor for tropical development in the Atlantic and also causes nasty hazy skies when it is so densely concentrated.

The Sahara is the greatest deposit of sand and dust particles in the world, stretching about 3.5 million square miles across northern Africa. Rainfall is rare across much of the Sahara because it is limited by persistent high pressure with resultant sinking and drying of air. Persistent northeasterly winds, squeezed between an area of high pressure over the northern Sahara and low pressure over the equator, are often strong enough to stir loose sand and dust in the Sahara. The smaller dust particles can be lofted up to 8 km (5 miles) high into the sky. Strong winds can blow over thousands of square kilometers of the desert and they can scour enormous volumes of dust from the surface. The amount of dust is said to be in the millions of tons.

Sometimes large dust clouds can traverse westward across the Atlantic as they get steered by trade winds. Under favorable settings, dust aloft can reach customary tropical cyclone breeding areas. The clouds of dust are associated with large zones of dry air, which is an inhibiting factor for tropical storms and hurricanes.

The large zone of dust and dry air has been one of the factors in the recent quiet state of the tropics in the Atlantic. Another large cloud of dust has moved in mid-July off the western coast of Africa and appears like it will continue to move westward across the Atlantic (see image bellow).

Beautiful sunsets are observed since the Saharan dust clouds resides so high in the atmosphere. The dust particles act to scatter certain wavelengths of light, allowing red hues to be illuminated.

Sources: CIMSS Satellite Blog, SSEC, MODISMiami Herald, Palm Beach Post, AccuWeather


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  1. I find it hard to believe you living in Vieques are not aware of its past and present. No, you don’t have to go clear across the globe to Japan. Its right there over 10 tons of military and industrial waste. Notice I say military. That covers a very broad range of contamanents. Your little spots are due to the Naval occupation in Vieques and Cuelebra. Are you not aware of your surroundings or do you not know of the past and present illnesses and deaths these war games have brought to your Island? I’m sorry but this is just another point of the ignorance of the majority of Puerto Ricans that live in P.R. There treated as second rate United States Citizens yet they go to war for the United States of America. The U.S. makes so much money off of the Common Wealth it is rediculous. And yet North Americans complain a think that its the other way around, ignorance I say. These are facts not personal attacks on either the U.S. or Puerto Rico. Puerto Ricans talk, talk, talk, complain, complain, complain. And yet less then 2% are in Washington fighting for Puerto Rico. It’s a shame Boricuas would rather watch the trashy gossips programs and amuse themselves then actually do anything about anything. And I mean anyting. I know, I’ve lived here and live here now. I also served as a United States Marine Corps for over 8 years. My father served for 22 years as well as my uncle and cousins. I am a forth generation military Veteran. I’m North American and I am leaving this God forsaken Island. Please forgive my english, I’m what you would call in the FMF a “ROCK” but I am very good at other things. The Marine Corps made sure of that.
    Semper Fi
    You want change, make a decision. Statehood or Commonwealth. As a state there will be major changes. No Medicare cut backs, no corrupt politicians stilling millions of Federal money over a 50 year period including money from the Puerto Ricans living in Puerto Rico. No starting of projects by one party costing millions only to be scraped by the new governing party.

  2. I live since 19 years on St.Barthelemy , FWI . We have this dust everywhere ,need to clean your windscreen every day , clean house , shop all 3 day’s from grey dark greasy dust , my wife became asthmatic under certain weather conditions .
    I’m working on leaving the caribbean soon , the air quality is bad for humans and animals .

  3. I live in Vieques, Puerto Rico. Following rain, during the past couple of months, I find dark spots deposited all over my outside porch and it’s railing. They range from 1/16 to 1/8 inch in size. Is this possibly attributed to the Saharan dust we are experiencing? Today, about an hour after I washed the porch, we had a moderate rain shower. Sure enough, I had dark spots all over it. Your considered opinion will be appreciated.

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