MONDAY DECEMBER 4 - ELECTIONS AND METEOROLOGY


As I was watching the Election Night television coverage back on November 7, particularly how the networks had trouble predicting who would carry Florida, I kept thinking: "I know how they feel."

Here's why. There's a data-collecting organization called Voter News Services that conducts exit polls on election day, and then supplies the networks with that information. The networks examine the data and project winners. In this past election, Voter News Services polled about 70,000 voters nationwide, less than one-tenth of one percent of the 100 million or so people who voted. When you think about it, that's not a very big sample on which to base forecasts.

Here's the weather connection. Good observations, and lots of them, are essential for a good weather forecast. But the truth is, the atmosphere is huge, and we only have observations of important quantities such as temperature, pressure, and humidity from a very, very small sample of that air. From those relatively few observations, we construct our "best guess" of the actual atmospheric conditions. It's sort of like calling elections based on just a small sample of voters. And it's that estimation over vast reaches of the atmosphere that often leads to misrepresented storms and consequently inaccurate forecasts.

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