Well, it is that time of year again – NOAA has just released their annual prediction for the upcoming hurricane season. And boy, will it be a doozy! They are predicting 12 – 14 named storms , 8 – 14 hurricanes, and 3 – 7 major hurricanes .
But, before we panic , it is worthwhile to ask ourselves “Do these ivory-tower yabbos actually know what they are talking about?” Fortunately, we have the tools available to answer that question: statistics!
Over the past eleven years, the folks at NOAA have predicted the number of named storms, the number of hurricanes, and the number of major hurricanes. That gives a total of thirty-three predictions. For each prediction, they can be too high, too low, or just right. That’s three possibilities. If they are just guessing (or doing no better than chance), then they should get 11 (=33/3) of their predictions right. If they are doing better than that, then we can assume that they actually know what they are doing.
In 17 (52%) of the predictions, they were right. That is definitely better than chance, so we may safely say that our tax dollars are well-spent when they go to NOAA.
What is interesting about the results is that they are too high (over predict) at about the same rate that they are too low (under predict). As you may recall from our previous foray into statistics, that is symptomatic of a gaussian normal function, which implies that the errors are due to random noise and not to bias. Thus, their models are good, and will improve as they find out how to squeeze more of the noise out of the system.
How can we tell that the models are improving? Look at the range of values on the named storms. Notice how it is about ten storms this year? That is the one sigma prediction; they are about 70% sure that there will be that many storms. If the range goes down, then that implies that the models are getting better (more precise).
Now, if you will excuse me, I have to go set up a second hurricane kit. Somehow, I don’t think that just one will do me this year…
 Think “Whopping great thunderstorm”. Millions in damages, very few displaced, almost no casualties.
 Think “Ike” (or Ike). Tens of millions in damages, a few hundred displaced, very few casualties.
 Think “Katrina” or “Andrew“. Billions in damages, thousands displaced, hundreds dead.
 Don’t Panic!