Tracking the Tropics: Saharan dust limiting tropical activity for near future

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TAMPA, Fla. (WFLA) — A weak tropical wave well south of the Lesser Antilles will produce showers, thunderstorms and gusty winds but has a near-zero percent chance of developing. The rest of the tropics are expected to remain quiet and no new development is expected over the next five days.

One reason for the lack of tropical activity is Saharan dust. A large plume of dust is traveling across the Atlantic and several more are right behind it.

The dust plumes come from storms over the Sahara. Strong winds kick up the dry top layer of soil and raise it high into the atmosphere. Easterly trade winds can then carry the dust over 5,000 miles to the Caribbean Sea, depending on the size of the plume.

The dust is normally between 5,000 and 20,000 feet high in the atmosphere and typically limits tropical activity.

The plume of dust is mixed in with very dry air and usually contains strong winds, neither of which is good for tropical convection. The plume is about 50% drier than the rest of the tropical atmosphere in the Atlantic.

The mid-level winds run 25 to 55 mph and can rip storms apart or prevent them from organizing in the first place. Research is still being conducted on how the actual dust particles affect the development of tropical cyclones.

The areas are also typically warmer and can lead to sinking air and more stabilized air.

When the plumes of dust are able to travel all the way into the Gulf of Mexico, they can create hazy skies, which lead to colorful sunrises and sunsets.

NASA is even studying how the dust plumes lead to red tide in the Gulf of Mexico. Every year the plumes make their way over from Africa. Mixed in with the dust is iron from the topsoil. The iron will end up in the Gulf and actually fertilizes the water which can begin the process of a toxic algae bloom.

That happens every year and does not necessarily correlate with large red tide blooms. Research is still being conducted on this topic to potentially predict red tide in certain areas.

The plumes we are currently seeing coming off the coast of Africa are quite normal. The plumes typically begin in mid-June and run through mid-August, peaking somewhere in the middle. According to NOAA, the plumes of dust seem to rapidly subside after mid-August, which is also why we see an uptick in tropical activity in August and September.

Tracking the Tropics is keeping you informed throughout the hurricane season. Watch live every Wednesday at 2 p.m. ET for an update.

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