Patricia shows need for better hurricane forecasting


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Adam Sobel: Hurricane Patricia became a Category 5 hurricane suddenly and shortly before landfall

Sobel says we need to find ways to predict intensification of storms farther in advance

Editor’s Note: Adam Sobel, a professor at Columbia University’s Lamont-Doherty Earth Observatory and Fu Foundation School of Engineering and Applied Science, is an atmospheric scientist who studies extreme events and the risks they pose to human society. Sobel is the author of “Storm Surge,” a book about Superstorm Sandy. Follow him on Twitter: @profadamsobel. The opinions expressed are his own.

CNN —  

The symmetry would have been pleasing to the eye if we didn’t know what it meant. Hurricane Patricia, in satellite imagery from early Friday, before landfall, presented a perfect doughnut shape with a precisely circular eye. As a rule, that clean, textbook appearance means deadly. That rule was right in this case, and we knew it as soon as it happened. But we hadn’t seen it coming.

Better than satellite-based estimates of hurricane intensities are the direct observations we get when a scientifically instrumented airplane flies right into the center of the storm.

In the Atlantic and eastern Pacific, our Air Force’s “Hurricane Hunters”, and sometimes scientists from the National Oceanic and Atmospheric Administration (NOAA, the parent agency of the National Weather Service), make such flights into all hurricanes that pose a threat to land. They flew into Patricia a number of times before landfall.

Adam Sobel
Eileen Barroso
Adam Sobel

So when the winds reached that unprecedented 200 mph, the National Hurricane Center’s advisories and forecasts immediately reflected the extreme danger the storm posed. Not before that, though.

When a major hurricane approaches, preparation is essential. But there was not much time for the Mexican towns in Patricia’s path to prepare. While the NHC had been forecasting a landfall in roughly the right place since the storm formed on Tuesday, and had anticipated the possibility of “hurricane conditions” at landfall, there was no indication that the storm might become the record-breaking, ultra-intense monster that it did. Until it did. Not quite at the last moment, but close to it.

Patricia went from tropical storm, the lowest category in the Saffir-Simpson scale by which we rate hurricanes, to Category 5, the top of the scale, in about a day. Then it kept going, exceeding the Category 5 threshold by 45 mph and breaking the intensity record for any Eastern Pacific or Atlantic Hurricane.

Some scientists argue that the scale should be extended for rare storms like this – that we should add a category 6 or even 7. If this sounds like a science fiction disaster movie to you, you’re not wrong; it is one.

When a tropical cyclone’s winds strengthen by 35 mph in 24 hours, it is said to have undergone “rapid intensification.” Rapid intensification is a well-known, serious problem for forecasters. The models they use often fail to predict it. And rapid intensification within a day of landfall is the truly frightening scenario.

Patricia intensified not just by 35 mph, but by over 120 mph in 24 hours. That’s not just rapid intensification; that’s mild-mannered Bruce Banner turning into The Hulk in just moments. And Patricia completed the transition less than 24 hours before landfall, which is like Banner turning green while standing in downtown Manhattan.