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Matthew’s Catastrophic Track

Our thoughts are with everyone affected by Hurricane Matthew, which hit from Caribbean countries to the United States, bringing so much loss of life and destruction of property.

The devastation from some of the worst tropical cyclones of the past has come from primarily wind (Andrew, Charley), coastal flooding from surge/waves (Sandy, Katrina), or inland flooding from rainfall (Agnes, Allison).

Matthew brought it all.

The hurricane took a track which was nearly a worst-case one for maximization of impacts for Haiti, Cuba, the Bahamas, and the southeast U.S., and in some respects was unusual.

That started with official classification going straight from a strong tropical wave to a strong tropical storm in the Windwards, where the first storm-related fatality occurred, and swerving close to South America with one person losing their life there.

Matthew_catastrophictrack
The central core, which is the strongest part including the eyewall, battered both Haiti and Cuba, the extreme western and eastern parts, respectively; yet by just clipping each island and not spending much time over the mountainous topography, that core was not sufficiently disrupted and it was able to quickly reorganize and reintensify upon emerging over the Atlantic.

Following that, there was a battering of the Bahamas given the hurricane’s NNW movement paralleling the islands’ orientation.

While impacts in northeast Florida would have been worse had the center been just a little farther west, they were nevertheless major even with the track being offshore. (And if the center had slammed directly into the peninsula, the hurricane would likely have been weaker in its path along the Georgia and South Carolina coast.)

My colleague Dr. Matt Sitkowski, who resides next to me at TWC, is one of the world’s leading experts on the phenomenon known as an “eyewall replacement cycle,” including his doctoral dissertation being on that topic.

That is a process by which a small eyewall (and eye) is replaced by a larger one, and which occurred as Matthew moved from the Bahamas toward Florida. Ironically, while that resulted in Matthew’s wind speeds lowering from Category 4 to 3 intensity on the The Saffir-Simpson Hurricane Wind Scale, expansion of the area of strong winds resulted in impacts being more severe on the Florida and Georgia coast with a track of the center offshore than if that core had stayed intense but very compact.

This radar loop shows the evolution from a small-diameter eyewall (ring around the eye) to a larger one forming in a concentric circle around the smaller one, to that outer eyewall becoming dominant. (The flicker partway through the loop is when the radar source changes from Miami to Melbourne.)

Matthew_eyewallreplacementradar2a

Zooming in, this was something never seen before, because it has not happened during the weather radar era: The eyewall of a category 3 or higher hurricane moving up along this part of the Florida coast in this direction.

Matthew_neverseen_small

As Matthew moved north, although its peak wind velocities continued to lower to Category 2 and then to Category 1, another transformation was taking place: The heaviest rain, rather than being symmetric around and relatively close to the center, expanded to the northwest as the hurricane became less tropical and interacted with a weather front.

The combination of that and already-saturated soil from previous rainfall resulted in the terrible flooding in the Carolinas.

Matthew_Carolinasrainfall

Finally, before exiting out to sea, “post-tropical” Matthew brought storm surge and strong winds from the Outer Banks to southeast Virginia, and even brushed southeast New England with rain and wind.

Fortunately in the wake of the storm has come good autumn weather for the start of what is going to be a long recovery process.

 


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