Central Texas deals with Saharan Dust from tropics

Monday's weather introduced another hazard to contend with thick haze. 

The haze over Austin is an extra bit of wild weather Central Texas has to deal with. This is in addition to the record heat wave the state is experiencing.

The haze is dust from the Sahara Desert that made its way all the way across the Atlantic Ocean and into Texas.

The dust is from massive sand and dust storms that blow across the largest desert on earth. Those dust storms loft tiny particles far into the upper atmosphere. Once it gets high in the atmosphere, a portion of the dust will move south and get caught up by the tropical easterlies.

Those winds transport the dust across the Atlantic Ocean, into the Caribbean Sea and Gulf of Mexico. Our visibility levels decrease once that dust gets pulled back north around a huge area of high pressure.

The same high-pressure system that is roasting Texas with record heat is also working to pull the Saharan dust out of the tropics. High pressure systems rotate clockwise, and Texas is sitting on the western side of the high. That’s why the winds have been from the south day in and day out. Those same southerly winds are dragging the Saharan dust up from the Caribbean Sea and Gulf of Mexico and into Texas.

The dust comes from dry lake beds in northern Africa and does have some benefits. It helps to fertilize the soils in the rainforests, Caribbean islands, and marine life. It also significantly decreases the potential for tropical storms to form by drying out the upper atmosphere.  

Here at home, it decreases temperatures slightly by scattering sunlight. For example, on Monday we only broke record high temperatures by 1° compared with Sunday’s 2°.

The downside is the dust has elevated air quality issues in Austin to Unhealthy for Sensitive groups, which is a 3 on a scale of 6. That means that those with breathing problems could have trouble breathing because of the dust. 

The poor air quality could last for a couple more days, eventually clearing as the high-pressure system shifts back west.