Storm Ophelia was so unusual, it was literally off the charts

Over the weekend, post-tropical cyclone Ophelia hit an unusual place, Ireland — so unusual that a graphic depicting the storm’s high-speed winds was abruptly cut off. That’s because so few tropical cyclones travel so far northeast that the US National Hurricane Center (NHC) doesn’t include the area in its wind forecast graphics.

Ophelia started out in the North Atlantic as a tropical cyclone that gathered strength as it traveled northeast, briefly becoming a Category 3 hurricane. The storm ventured farther east than any other Category 3 hurricane on record, the New York Times reports.

To help people prepare for a storm, scientists at the NHC prepare maps showing the color-coded probabilities of where high-speed winds might reach. If a point on the grid is highly likely to see sustained, tropical-storm-force winds, it’s colored in purple. If it’s unlikely, green. These maps include a thousand different plausible scenarios that could play out in the hours to days after the hurricane forms, says Michael Brennan, senior hurricane specialist at the NHC.

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