National Hurricane Center’s Isaias scorecard
Bottom Line: The passing of Isaias showed the very best and based on one’s perspective – potentially the worst of what the National Hurricane Center provides. Starting with the positives. Accuracy. As I illustrated last week, the National Hurricane Center has become extremely accurate with the cone in recent years. Two-thirds of the time a storm travels somewhere within the 5-day cone of uncertainty. Isaias is no different. Here’s a look at the Hurricane Center’s original 5-day cone:
Here’s Isaias’s actual path:
The hurricane turned tropical storm turned hurricane passed well within the original cone. That’s a win for accuracy. In fact, as it turned out their original five-day cone which projected a tropical storm approaching Florida was more accurate than the forecasting less than a day out. The Hurricane Center gets an A for the accuracy of the cone. But then there are the advisories...
I’ve long been concerned about the implications associated with the “boy cries wolf” effect with hurricane forecasting. Preparing for the impact of a hurricane is a much different conversation than the preparation for a tropical storm for most people. It’s stressful, it can be expensive both in prep and to pay for help with shutters, boards, etc., it’s time consuming. We tend to have a very short tolerance for being put through those paces for nonevents. And this is where I have concerns with the National Hurricane Center. It’s not based on their accuracy but decision making in issuing warnings.
I’ve long held the belief that the Hurricane Center is inclined to error on the side of CYA with intensity, rather than to use a pragmatic approach with complete transparency. It’s perhaps easier for them to issue a hurricane warning and have it turn out to be nothing, than to not issue the warning and have the inverse occur. On Friday when the National Hurricane Center issued a hurricane warning, the odds of the impact of hurricane force winds anywhere along the South Florida coastline were under 50%. By Saturday afternoon those odds had dropped all of the way down to under 10%. At the last update which included a hurricane warning, the odds were under 3% and yet the warning remained. According the National Hurricane Center, this is what a warning means: A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, in this case within 24 hours.
Does that jibe with a sub 50%, 10% or 3% chance? This is where the Hurricane Center gets an F in my view. Be fully transparent. Would you have prepared differently if you knew there was never a likely chance for a hurricane impact this weekend? We should at least have the information to make an informed decision. There should be greater transparency. In my view the bigger risk than a 3% chance of a hurricane impact, is when there’s a near certain impact coming but people choose not to prepare because the alarm was sounded over a non-South Florida event.