Tropical Storm Karen is No. 11: How Many More Atlantic Hurricanes This Year?

The last time we had a storm whose name started with "K" in the Atlantic region, it was ... well, you know already. The recently-named Tropical Storm Karen, then, provides still more proof (as if anyone needed any) that while 2006 may have been a relatively quiet year, in 2007 we're back to busy hurricane seasons -- and there's a long way yet to go.

Karen is the 11th named storm of the year, and the tropical Atlantic seems quite active lately -- I doubt this will be our last tropical cyclone to earn a letter of the alphabet. As a result, your Storm Pundit thinks we can now say with some confidence that the low-end projections for Atlantic hurricane numbers, released earlier this year, were probably a bit too low. In other words: Let's hazard a prediction that someone else's prediction fell short of the mark.

That someone is the U.K. Met Office, which uses an advanced technique based upon climate modeling to forecast storm numbers in the Atlantic, and put out quite accurate predictions for 2005 and 2006. In June of this year, the Met Office forecast between 7 and 13 named Atlantic storms between July 1 and the end of November, with the "most likely" number being 10. That's a below normal forecast; the 1990-2005 average for July-November storm numbers is 12.4.

The Met Office's forecast excluded the year's first two storms, Andrea and Barry, because they occurred before July 1. There have been nine named storms since then, though, and with La Nina in place, you've gotta figure there are going to be more. So it looks like the Met Office's "most likely" number, 10, will probably fall too short .. and the upper range prediction, 13 named storms, may fall short as well.

We'll see.

And what of Karen? This storm may or may not develop into a serious hurricane, and the forecasts keep it safely out at sea, far from land. Still, Karen's circulation is simply gigantic. If you wanted to fit the storm into a longitude/latitude box, you'd need at least ten degrees in both directions. NOAA As a result, Karen provides an opportunity to comment on the important issue of hurricane size, which varies dramatically. Media commentators like to harp on a storm's easy-to-grasp Saffir-Simpson category -- 1, 2, 3, 4, 5 -- but in reality this classification system is pretty limiting. Saffir-Simpson ratings are based entirely on wind speed; but for obvious reasons, the amount of damage caused by a land-falling storm depends upon many factors other than its intensity. One reason our last K storm, Katrina, caused such a high storm surge at landfall was because of its immense size.

So while Karen isn't currently forecast to hit anything, bear in mind that if it gets near land and maintains its present size, this storm has the potential to hit many things.