Tuesday, August 23, 2011

Stop doing this

Tell you what. Let's stop writing this headline now, and then we won't have to write it again every day through Saturday.

To review the bidding, here's the relevant graf from Monday's story:

The National Hurricane Center's official forecast is for Irene to be a 115-mph hurricane when it makes landfall early Saturday near Myrtle Beach, but meteorologists cautioned that much of the coast -- from south Florida up to the Outer Banks -- could be the landfall site.

By Tuesday morning (shown), forecasters had "shifted the bulls-eye of Hurricane Irene northward* to the Wilmington area." And by evening:

The focus of preparations for Hurricane Irene moved up the Carolinas coast Tuesday, with forecasters now saying the worst of the storm will slam into the Outer Banks.

If you're starting to see a pattern, you can guess what follows:

But meteorologists at the National Hurricane Center once again reminded the public that the forecast track of the storm could shift in either direction.


That's not entirely true. More likely, they "reminded the public" that there's more than one direction a storm can shift in, and over the next four or five days, there's a pretty good chance it will shift in several of them.

How good of a chance is a different question, and there's where journalism needs to set aside its drive to be authoritative, certain and up-to-the-minute and actually indulge in a little probability-based reasoning. Here's how the National Hurricane Center describes the "cone" that contains the "probable path of the storm's center":

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast "cone", the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time.

So about two-thirds of the time, the center of the storm will be somewhere within the cone for all five days of the forecast -- based on how tropical cyclones have behaved before. That's interesting and important. If I was deciding whether to lay in some bread and water or to see if any relatives on higher ground were willing to put up with me for a few days, I'd call it substantially more important than a pile of inane chatter about whether the notional "bulls-eye" had shifted a few dozen miles in the forecast for Saturday. Indeed, if I was still living on the southern N.C. coast and you had shown the ability to understand how margins of error work, I'd be a fairly attentive reader right now.

Believe it or not, people still pay attention to the "legacy media" when there's a potential disaster in the offing. They may pay attention to your newspaper's website or its Twitter feed rather than the dead-trees product, but they're paying attention to you for a reason. If you want them to keep paying attention, be useful. Don't spin your wheels on crying wolf -- they notice -- when you could be providing actual information. And if it makes you feel better, "study says."



* More like east-northeast, but that side of the state has always been foreign territory to the Observer..

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