Why It’s Hard to Forecast the Weather
Sept. 22, 2015 - Weather forecasting is a tricky business. Jason Samenow, weather editor for the Capital Weather Gang at the Washington Post, explains how forecasters rely on computer models to help predict the weather, and why their forecasts may be more accurate than you think.
Videographer: Gabriella Garcia-Pardo
Senior Producer: Jeff Hertrick
Editor: Nick Lunn
Forecast Model Animations: WeatherBELL Analytics
Transcript
Jason Samenow
Weather Editor
The Washington Post
People have short memories, so you're only as good as your last forecast, so if you mess up a forecast especially a high-impact forecast, people are going to remember that.
A three day forecast today is about as accurate as a one-day forecast was in the 1970s.
If you look at a one-day forecast for example of temperatures, we're within about 3-4 degrees of being exactly right, 90% of the time.
You have to as an expert give your best bet, but you also want to communicate that, hey look, especially with a high-impact forecast, there's this range.
There's this idea of chaos theory which means that some point there's a limit to how far out you can predict. Just because a random fluctuation somewhere can lead to big changes which propagate and grow and get bigger and bigger as you get farther out in time.
There are several forecast models we use, there is a American model known as the GFS model that is a global forecast model which provides forecasts out to sixteen days into the future.
And then the European Center for Medium Range Forecasting has a model called the European model, if you look at statistics of how accurate the models are, the European model is the most accurate.
Some storm the European model will do better, other storms the GFS model will do better. Even though statistics tell you that the European model is the best you can't take it to the bank in every case.
When you compare the jobs that weather forecasters due in terms of batting average compared to other professions wether it's diagnosing a disease as a medical professional or wether it's doing economic forecasting, or wether it's an athlete who has a batting average of .333, weather forecasting is actually pretty goof when it comes to performance.
