TIMELINE: Large Saharan Dust wave to impact Florida weather

ORLANDO, Fla. - Saharan Dust varies in intensity each year. This year, the Atlantic basin has experienced several large and dense waves. 

This next approaching dust wave will help lower afternoon high temperatures early next week as less sunlight reaches the ground.  Depending on the number of showers within the dust, you might notice a dirty residue on cars, mailboxes, and other surfaces after the rain early next week.

What is the Saharan Dust? Where does it form, and what carries it across the Atlantic?

Saharan Dust outbreaks occur every summer to varying degrees across the Atlantic Basin. The trade winds kick up the dust and help carry it west off the coast of Africa. Tropical waves also help track along the Saharan Desert's edge and loft immense dust into the air. 

This plume of dust resides somewhere between 5,000 and 15,000 feet in the sky, so it is not near the jet stream. SAL (the Saharan Air Layer) typically starts as soon as mid-June and can occur as late as the end of September. The majority of dust passes through the Atlantic in July and August. 

New outbreaks are generated every 2–5 days.

How big is this new wave? When will it arrive in Florida? How big will it be? How much will it cover Florida?

This current wave is one of the largest ever recorded in July, with some dust reaching Florida this weekend.  

Central Florida will see the Saharan dust arrive on Saturday afternoon and evening, peaking on Sunday and Monday. Expect the sky to appear gray, murky, and hazy across the region.

What does it mean for the weather here?

It means that it will visibly look very hazy and murky most of the day. This dust will also, to some degree, help lower the afternoon high temperatures over Central Florida. Due to the dust, temperatures will drop below average, hovering around 90 degrees by Tuesday.

The plume that arrives over Florida by Sunday could be so dense that it reduces air quality issues, especially for sensitive groups. This also means that if it rains, sometimes dust can show up on your car and other things on the ground as it gets embedded within raindrops from thunderstorms aloft. 

Sometimes referred to as "dirty rain" by Floridians. The dust can also contain bacteria that cause algal blooms and harm coral reefs.

By Thursday, the weather will return to a more typical pattern. Afternoon shower and storm chances will rise to 60%, affecting the entire area rather than just a few counties, as seen on Wednesday.

What does it mean for the tropics?

Saharan air and dust significantly hinder tropical development. The moisture can not condense into clouds and grow as easily when the air is so dry and dusty. This limits thunderstorm development, which in turn prevents tropical cyclone genesis. Due to the dust, the Atlantic basin is expected to remain quiet for at least another week.