The hurricane forecasts from NOAA and various other sources are calling for a very busy season ahead. News headlines over these predictions have ranged from exuberance to extreme scariness.
Don’t get me wrong, the signals are certainly there for an above-normal season. But the official forecast is for 14-23 named storms…quite a spread by any statistical definition. Yet hitting the bottom end of that range would simply imply a slightly above-normal season. Hitting the high end…well, that’s a different story. But you get my point.
Comparisons to the “Katrina” year are frequently cited, but making such analogies at this very early stage of the season probably go a little too far. It may turn out to be warranted, but there are atmospheric and oceanic factors that could change that would alter things.
Sea surface temperatures (SSTs) over the prime hurricane “breeding-grounds” of the tropical Atlantic are currently running 1-2 degrees above normal, largely due to light trade winds earlier this year. There is a decent chance that these warm SST anamolies will decrease in magnitude over the coming weeks and months. As storms eventually do develop, mixing and upwelling over these warm waters could ultimately cool the water temperatures. The net effect could end up being less, rather than more activity, later in the season. A possibility.
With respect to a weakening El Nino, transitioning to a La Nina, a big part of the modeling that has been used to make the case for an extreme season. While it certainly looks like that transition may happen, there is no certainty of how strong it will be. Unexpected changes in this dynamic could imply fewer storms than early predictions indicate.
Bottom-line… we need to be prepared for an active Atlantic hurricane season, but as with any weather forecast, conditions can change, even when we think they cannot.