Here's the Scoop: April 22, 2009
What are the chances?
Some stunning news was reported this week on my Home Page. It seems that “only half the population understands what a precipitation forecast means well enough to make a fully informed answer to that tricky question of whether or not to bring an umbrella.”
That leaves half of us all wet, I guess. Or not — depening on one’s luck.
Here’s how the concept was explained in the story: If a forecast calls for a 20 percent chance of rain, many people think it means that it will rain over 20 percent of the area covered by the forecast. Others think it will rain for 20 percent of the time.
The reality: When a forecast says there is a 20 percent chance of rain tomorrow it actually means it will rain on 20 percent of the days with exactly the same atmospheric conditions.
Putting it another way, on that day there’s an 80 percent chance there will be no rain anywhere in the forecast area.
Isn’t that what you thought? Me too.
Designed to confuse
If it’s this difficult to understand whether it’s going to rain or snow, imagine how folks like the ones who write the fine print on warranties must snicker at the chances of someone being able to interpret their work.
I actually have been trying not to pay much attention to weather forecasts. Sure, I recognize there are benefits to rain (I don’t have to wash the car!) but it’s still hard not to take a peek.
What I really enjoy are those folks who can look at a forecast of 80-degree days and blue skies for nine days, with showers predicted on the 10th day and still find a dark cloud.
“It’s going to rain,” these “rays of sunshine” grumble.
Being an optimist at heart, I try to laugh off such comments with remarks like: “Good, I was never comfortable with the idea of drying up like some unidentifiable health food.”
Let’s blame others
But back to the study showing how most of us can’t interpret a weather forecast. I’m not going to dispute these findings, but I somehow think that this “research” was sponsored by forecasters who, well, can’t forecast.
After all, being a weather forecaster is pretty much a thankless job. The training for this position must come with a bunch of test questions where the correct answer is: Rain and snow are bad. Always.
Sure, there’s a certain “gray factor” that is hard to escape on a dreary day, but precipitation has gotten a bad rap. We should embrace rain and snow. Even if we have no idea when it’s coming — and the forecasters don’t either.
The story on forecasting concludes that understanding how forecasts are interpreted could be useful to government officials who have to decide on school closings, road closures and other potentially expensive measures. And don’t forget that we can also predict when everyone will be in a bad mood.