Monday, April 30, 2012

2012 Hurricane Season Forecast

Consensus is shaping up that the 2012 hurricane season will be a relatively inactive one compared to the recent "average" of the last 17 years. Most forecasters are calling for seasons that are below the average of 15 named storms, 8 hurricanes, and four major hurricanes that have developed across the Atlantic basin between 1995 and 2011.  The 15/8/4 average is above the long-term average of 11/6/3 that the Atlantic has generated going back to the 1800's.   In comparison to all time averages, this season will shape up as a relatively "typical" season but in our recent norms it really will be a bit slow.

The reasoning for that likely lies in two factors that are developing across the Atlantic and Pacific.  First, the Atlantic...where tropical oceanic temperatures off of the West Coast of Africa are below average at this point by a degree or two from normal.   Cool pools of water off of Africa will inhibit tropical development during the prime "Cape Verde" season later on this won't necessarily eliminate the potential for long track tropical cyclones but it will certainly slow down their development if these cooler waters hold in place through the summer season.   That said, waters in the Gulf of Mexico are generally milder than average at this point -- and it's possible that the hub of activity this year generates out of the Gulf due to not only warmer waters there.

The other factor is the presence of a developing Nino in the Pacific.  Ninos tend to wreak havoc on the Atlantic pattern, changing the upper level pattern to a more unfavorable setup as wind shear from Pacific tropical cyclones and from a more active subtropical jet tear through developing tropical waves.  This could be one of those situations where the Caribbean may be relatively quiet this year compared to past years as the upper level pattern...if the "typical" Nino one were to develop...would weaken or shear storms apart if they were to try to develop in the Caribbean.

In any season, the meme "all it takes is just one storm" always holds is the 20th anniversary of Hurricane Andrew this year and 1992 was more or less a "one hit wonder" type season as Andrew tore through South Florida and Louisiana.  Predicting whether there will be "one" or if any development merely bounces out to sea or ends up as a soggy rainmaker is a tough proposition to nail down at the end of April.  That said, this season will likely shape up as a quieter season on the whole from a numbers standpoint.

Our forecast is for "just" 11 named storms to develop, with the vast majority in August and September (eight of the 11).  Due to the developing Nino in the Pacific, I expect the season to quietly whither away earlier than usual...I don't foresee November activity and our October prediction is for just one storm.

In terms of favored areas, the best chances for tropical cyclone activity will likely be the Gulf of Mexico and off of the Carolina coastline.  We could see a number of "home brew" setups where storms organize from dying cold fronts or from weak tropical disturbances that move into more favorable environments.  That said, it doesn't look like it will be as active a season as 2010 or 2011 -- both byproducts of a favorable La Nina pattern and a very warm Atlantic.