Tuesday, October 29, 2013

Not Wrong, But Not Right

Atmospheric scientists have a really tough job: predicting weather. This year, 2013, has seen a hurricane season that lived up to predictions, and yet, did not:

In August of 2011, Tropical Storm Irene became the worst storm to hit New York since 1972. A year later, Hurricane Sandy made Irene look like a drizzle, and Governor Andrew Cuomo referred to the danger posed by the massive storms as the "new normal." So it was hardly comforting for New York, still largely unprepared for another Sandy, when the National Oceanic and Atmospheric Administration predicted in May that there was a 70 percent chance this year's hurricane season would be more active than normal, with three to six major (category three or higher) storms.

Then ... nothing happened. With the season winding down, there have been twelve named storms, two hurricanes, and not a single major hurricane to date. On the surface, it seems kind of embarrassing. But one of the lead scientists behind the NOAA forecast says that it is just proof that you shouldn't pay attention to hurricane projections anyway.

[…]Consequently, while the number of storms predicted was on target, "They just didn’t find an environment that was conducive to go on and become strong," Franklin says. "So we had lots of weak systems that didn't last very long."

What may have happened, scientists speculate, is a phenomenon called “sinking air”.

When air rises, it carries moisture from the surface, especially the ocean, to upper levels of the atmosphere. This creates instability and instability breeds thunderstorms and thunderstorms seed hurricanes.

When the opposite happens, when air sinks, it brings drier air down, and basically soaks up any thunderstorms. They’ll still form but they get short-circuited.

This is important because of the human propensity to a short attention span.

It’s one year since Superstorm Sandy hit New York City, and we’re still digging out. We can take preventative steps, but there’s nothing like being prepared.