One month after Irma: Why did it take the track it did?

A matter of miles could have made Irma's impact on Florida much much worse.

JACKSONVILLE, Fla. -- It's been one month since Hurricane Irma brought heavy rain, wind and flooding to our First Coast. Many of you may still even be feeling the after effects of the storm, but do you ever wonder: Could it have been any worse? Why did Irma take the track that it did? Let's dive into the way certain atmospheric forces nudged the storm and why a matter of miles made all the difference.

Irma quickly proved it was a force to be reckoned with by becoming one of the strongest hurricanes we've ever recorded in the Atlantic Ocean. This frightening storm was led toward Florida by a strong area of high pressure in the Atlantic called the "Bermuda High." Hurricanes glide west along the southern edge of this high pressure zone and depending on its strength, a storm can take a more northerly or southerly track.

Forecasts on the Friday before Irma's landfall, showed the southeast coast of Florida in the National Hurricane Center cone driving Irma up the state's spine. This would have resulted in disastrous storm surge for Miami and its beaches.

However, there was also a mass of dry air and low pressure that had to be taken into consideration. Meteorologists call this a "trough" and it kept Irma from trekking farther west into the Gulf of Mexico. We knew this trough would eventually weaken the Bermuda High and bring Irma north, but the strength and speed of the trough is extremely tricky to predict. So the big question was, "When would Irma turn north?"

The trough moved very slow, so forecasts by Saturday started taking Irma farther west up the Gulf coast of Florida where over 4 million people live with a possible worst case scenario from the Keys to the Panhandle.

By Sunday morning, the trough's dry air began getting sucked into Irma's circulation weakening the storm and steering it farther north. As Irma absorbed the trough, the hurricane wobbled, passing far enough west of Orlando, but not far enough to hit Tampa and-or getting back over the Gulf where it could restrengthen.

Still reading? Good! Believe it or not this is just a brief overview showing how many variables there are when forecasting these massive storms. Not only that, but every single storm is different.

Let's take our most recent storm Nate, plus Matthew for some comparison. Nate was tugged north, away from Florida, thanks to strong high pressure and no influence from a trough.

Matthew, on the other hand, was pulled along the southern edge of the Bermuda High just like Irma, but the difference was that we had a strong cold front, or trough, approaching and the high pressure didn't budge either. Therefore, Matthew slid between these two air masses barely clipping Cape Canaveral and eventually making landfall in South Carolina. In the end, the cold front won which made Matthew make a sharp turn back out to sea.

Bottom line: timing is everything! If you don't have these perfectly timed cold fronts or strong enough of a high-pressure system for example, then we can be at risk.

So trust your First Coast News Storm Experts. We are here to break down all of this complicated meteorology and get you through the rest of this hurricane season and hurricane seasons to come.

© 2017 WTLV-TV


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