This had been predicted to be one of the busier hurricane seasons of recent years. It turned out to be one of the quietest. What happened?
“A combination of conditions acted to offset several climate patterns that historically have produced active hurricane seasons,” explained Gerry Bell, NOAA’s lead seasonal hurricane forecaster. “As a result, we did not see the large numbers of hurricanes that typically accompany these climate patterns.”
Prior to the beginning of this season, which started June 1, forecasters were expecting to see higher-than-normal water temperatures and lower-than-normal pressure in the deep tropics, where most tropical systems form. Forecasters also expected water temperatures in the tropical Pacific Ocean would remain in the cool or neutral range through the season.
All of these factors tend to boost hurricane activity in the Atlantic.
And during this season all of these things happened. And yet, there were no big storms.
“It turns out that there is an additional parameter that was not generally considered when making seasonal predictions,” said Chris Hebert, a hurricane forecaster with ImpactWeather, a company based in Houston.
Hebert said earlier this year, after it became obvious that the Atlantic activity would be well below normal, he searched for other factors at play and discovered that moisture levels in the midlevel of the atmosphere, about 18,000 to 25,000 feet above the surface, were well below normal.
I forget who said it, but as someone once said, true scientific advancement comes not with “Eureka!” but with “That’s funny…” This was one of the latter experiences, and with it the science of hurricane forecasting has advanced. This is how it’s supposed to work. Failure is a great learning experience. SciGuy has more.