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Tropics Watch: Here’s why tropical disturbances are struggling to develop during the peak of hurricane season

Hurricane season runs through November

Tropical development (Jonathan Kegges)

ORLANDO, Fla. – To be clear, this is a good thing.

If you are wondering why the peak of hurricane season has been pretty tame to date, the Pinpoint Weather Team will break it down in this story.

With that said, there is still a lot of hurricane season left to go, and while the actual number of storms may not meet some of the extremely active pre-season predictions, it only takes one.

The Pinpoint Weather Team identified limiting factors prior to the start of the season that could lead to a less-active season than predicted.

This is just one of the reasons why The Pinpoint Weather team used terms like impactful rather than ”explosive.”

Remember, these forecasts go beyond Central Florida. Beryl and Debby were both extremely impactful tropical systems to date.

The weather pattern suggested the storms that do develop would have a higher probability to impact land through the Gulf of Mexico and Caribbean.

To date, there have been four landfalls: Alberto, Beryl, Chris and Debby -- either in the Caribbean or along the Gulf Coast.

Why so quiet during peak season?

Everybody knock on wood for this one.

1. Saharan dust peaked late

Saharan dust had been prolific through late July into August. Typically, the yearly occurring phenomenon, dust from the Sahara Desert, peaks in July and then backs off during the peak months of hurricane season.

2. Tropical waves rolling off Africa further north

The Intertropical Convergence Zone (ITCZ), where winds from the northern and southern hemisphere come together to force up clouds and thunderstorms, has been situated further north than normal.

This has allowed tropical waves to exit Africa into a not-so-favorable environment, met by cooler waters and drier air. The ITCZ is forecast to gradually sag further south, however.

3. Stable atmosphere

This may be the biggest factor of the three.

A very warm upper atmosphere over the Atlantic basin has kept a relative lid on thunderstorm development. Instability is measured with cool air on top of warm air. With a warm upper atmosphere on top of very warm sea surface temperatures, there’s not much instability, or fuel, for thunderstorms to develop.

Without thunderstorms, tropical development chances are slim to none.

As the upper atmosphere cools a little getting into fall and the sea surface temperatures remain very warm, it will be interesting to see if perhaps the peak of hurricane season will be delayed by several weeks. Water cools much slower than air, so instability may be on the rise later in the season.

If a storm does find a favorable environment over the next couple of months, it will have the opportunity to become strong because of the extremely warm water temperatures.

Current disturbances

As of Sept. 2, the National Hurricane Center has highlighted two disturbances for possible tropical development over the next week.

There is a medium chance for two tropical depressions to form over the next few days.

There are no threats to Florida at this time.

Tropical development

About the Author

Jonathan Kegges joined the News 6 team in June 2019 and now covers weather on TV and all digital platforms.

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