2 Hurricane Forecasts, Both Uncertain, Both Scary

Here we go again: The early, early forecasts of Atlantic hurricane activity – which don't have any great track record for accuracy, but which everyone loves to yammer about – have now been released.

One comes from Phil Klotzbach and Dr. William Gray of Colorado State University (PDF). They are forecasting a busy year: 15 named storms, 8 hurricanes, 4 intense ones, and an enhanced probability of an intense landfall in the USA.

The other forecast comes from the British group Tropical Storm Risk (PDF). They forecast percentages of storms, but come up with something similar: 14.8 named storms, 7.8 hurricanes, 3.5 intense ones. They also see an enhanced U.S. landfall risk.

The two groups are responding to the same atmosphere-ocean conditions, or "predictors" of what the upcoming season would be like. Those include: a current La Nina event in the Pacific ocean (usually conducive to busy Atlantic hurricane seasons, and not expected to flip to El Nino by summer), an expectation of weaker-than-average trade winds over the tropical Atlantic (meaning less evaporation and therefore warmer oceans, as well as more "cyclonic vorticity" and therefore spin-up of storm winds), and an expectation of at least average sea surface temperatures.

Honestly, nobody knows what the season is going to be like, and these forecasts certainly don't count as "evidence." But my outlook, as usual, is one of guarded worry – things can be up or down in a given year, but when you consider some recent behavior in the Atlantic, it simply has to bother you.

NOAA

Consider, for example, a presentation given by National Center for Atmospheric Research hurricane specialist Greg Holland at the last American Meteorological Society meeting, back in January in New Orleans. Noting that we have seen eight Category 5 Atlantic hurricanes in the past 5 years, a number that is simply off the charts in comparison to official records of past activity, Holland questions whether or not these storms might represent a "bellwether" of climate shifts.

Now, having been at that meeting myself, I know that a lot of researchers disagree with Holland about whether you can use a mere eight storms, however extreme, to say anything scientifically defensible. Nevertheless, it's pretty hard to ignore the fact that there have been eight Category 5s in the Atlantic in 5 years, people! Two of them hit land at full strength last year. If this continues, one may eventually hit the USA at full velocity, and that could be a mega disaster.

So now comes the long wait for June 1, the official start to the season – even though, honestly, things don't get really active usually until August. Expect the predictions to become more accurate as the season nears. We'll see if they hone in on a consensus.

Meanwhile, expect the unexpected as well.