Communicating uncertainty to the public

Forecasting weather is a very imprecise endeavor. This is due in part to the fact that forecasts matter on very local scales. If I cancel a cookout due to a thunderstorm forecast, I won’t care that it rained everywhere else if it didn’t rain in my back yard. Given that the forecast will never be certain, how can forecasters communicate uncertainty to the public?

As the Washington Post‘s Capital Weather Gang wrote:

As much as we communicated the uncertainty, the forecast cannot be considered a success if the message we were trying to send … did not reach some people.

So what do they suggest? The high-level suggestion is to use a “traffic light” metaphor to indicate how people should proceed with their day. This benefits from being simple, but it has some key failings. As Jason Samenow noted, it needs to be broken into at least two dayparts. As many as five dayparts may be necessary: morning commute, day, afternoon commute, evening, and overnight.

Time-of-day isn’t the only issue. Thunderstorm forecasts are particularly sensitive to geography as well. Even if you’re only forecasting for a metro area, you may not end up with the same observed weather. So the system would need to account for multiple areas. If you divide the area into quadrants, that gives you 20 time/area combinations.

At some point, the simplified system becomes almost as complicated as the status quo. This means that the public will miss the nuance in the same way they do now. It’s a hard problem. An ideal balance between simplicity and nuance exists somewhere. But who can say where?

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