Weather

Saharan Dust in Tennessee? It's a possibility late next week!

Johnson City, TN - Forecasters continue to watch a plume of Saharan dust that has been traveling across the Atlantic into the southeast.  

Take a look at this GOES East satellite image taken on June 27, 2018.  You can see the Saharan dust, shown as a hazy beige-colored cloud that stretched from Africa to the Caribbean Sea.  This is called the Saharan Air Layer or SAL..

It is not uncommon for Saharan dust to move westward over te Atlantic from the west coast of Africa.  The dry, dusty air mass forms over the Sahara Desert during the summer and early fall months and then moves across the Atlantic Ocean every three to five days.

It is interesting to note that this dry air can often times create a stable layer dry, sinking air over the Atlantic which can in turn suppress hurricane and tropical storm development.  Large masses of dust can also produce more of a stable environment which causes the air to sink  That sinking air can prevent storms from spinning up or gaining strength.

Interesting fact from NOAA.  "Each year, over one hundred million tons of Saharan dust gets blown across the Atlantic, some reaching as far as the Amazon River Basin.  The minerals in the dust replenish nutrients in rainforest soils, which are continually depleted by drenching, tropical rains."

Take a look at this imagery from NOAA taken on July 9, 2018.  You can see Tropical Storm Chris off the Carolina coast and the remnants of former Hurricane Beryl in the Caribbean Sea and you can see the thick plume of Saharan dust on the north and east side of Beryl.

The Saharan Air Layer usually is found at heights of 5,000 feet to 20,000 feet in the atmosphere.  Upper level winds can move push the dust several thousand miles.  

It is interesting to note that the iron-rich dust particles that are found in Saharan Air can not only reflect incoming solar radiation, which cool the atmosphere,but those same particles can cool the ocean waters too as the amount of incoming sunlight is reduced.  

As this layer of Saharan air moves into the United states, those in the path may actually see some spectacular sunsets with the dust in the air.  The dust can also be dangerous for those with breathing problems if they have prolonged exposure to the outside air.

Here is an animation of the dust moving across the Atlantic from NOAA.

Saharan Dust moves across the Tropical Atlantic - NOAA

We have also been watching the plumes of Saharan Dust moving across the Atlantic and the Gulf of Mexico.  Dust could eventually move into the Tennessee Valley next week as a cold front moves into our area.  This could create hazy conditions across much of the south. 

This map from Storm Team 11 Weather chows the dust moving into our part of the state late next week.

 

 

 

 

 


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