WRAL WeatherCenter Blog

Predicting the atmosphere can be chaotic, difficult

Posted February 3, 2015

— The above video demonstrates how chaotic and difficult predicting the atmosphere can be.

This is an example of ensemble forecasting, where the initial conditions for each of 20 computer models are altered just slightly to account for the fact that we cannot observe the atmosphere perfectly. The goal here is to see how sensitive the atmosphere is several days out to small changes at the beginning.

The white lines represent winds in the upper atmosphere, blowing from left to right. The lines remain fairly tightly packed through Friday, but then go crazy after that, signaling a period of time where forecasts should be taken with many grains of salt.

It's not being wishy-washy, it's just an honest evaluation of how predictable a state the atmosphere is in. There's no sense faking high levels of confidence, when the ensemble members are all over the place. If nothing else, enjoy the artistic nature of the lines!


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  • John Dees Feb 6, 2015
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    And yet, you are sooooooo sure about global warming. Laughable.

    You guys cant hit the weather right 24 hours out. Not a slam, just the truth.

  • Doug Bradley Feb 4, 2015
    user avatar

    Yeah, yeah, yeah, yeah......where's the snow??