Another Grim Pre-Season Hurricane Forecast for the Atlantic

Especially since El Nino went away (PDF), hurricane watchers have been worrying about what kind of season we'll see in the Atlantic later this year. El Nino has a well known tendency to suppress Atlantic storms, contributing to quieter years like 2006 (click image). But now, we're expected to see El Nino-neutral or even La Nina conditions (the opposite of El Nino) over the coming months.

The latest forecast from Tropical Storm Risk (PDF), a group based in the UK, only heightens the sense that we may have a bad year ahead.

TSR has now raised its forecast for an active season:

Based on current and projected climate signals, Atlantic basin and US landfalling tropical cyclone activity are forecast to be about 75% above the 1950-2006 norm in 2007. This is the highest March forecast for activity in any year since the TSR replicated real-time forecasts started in 1984. There is a high (~86%) likelihood that activity will be in the top one-third of years historically.

By the numbers, TSR is predicting 16.7 named storms, 9.4 hurricanes, and 4.3 intense hurricanes (Category 3 or higher). A rival group, that of William Gray and Phil Klotzbach of Colorado State University, had also predicted an active year back in December, but the CSU forecast--14 named storms, 7 hurricanes, and 3 intense hurricanes--did not go as far as TSR now has.

The next forecast from Gray/Klotzbach will be on April 3; the next one from TSR will be on April 5. The National Oceanic and Atmospheric Administration has not yet released a hurricane outlook for 2007; I believe the first NOAA forecast will come sometime in May.

A cautionary note: It's important to view these forecasts with a grain of salt--they get more and more accurate as the season nears, and especially once it's underway. Also, none of these three statistically based forecasts was very accurate during the pre-season last year due to the failure to detect El Nino. Still, the picture they're painting is worrisome...