The Weather Notebook: Boguscane

Boguscane
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Computer models are a great help in predicting the weather, but just like human beings, they aren't perfect. Now that hurricane season is at hand, forecasters are watching the models closely to see if any tropical cyclones spin up. The models often provide several days' warning that a new cyclone will form. But forecasters have to sort out the real cyclones from the fake ones. It turns out that some computer models love to generate phony hurricanes. They're so common that forecasters now call them "boguscanes." I'm Dave Thurlow for the Weather Notebook.

What's behind a boguscane? For one thing, the models aren't yet detailed enough to include realistic thunderstorms, and you need these to kick off an actual tropical storm. Sometimes all it takes is a little moisture for the model to generate a boguscane, even when the other ingredients for tropical action aren't there. It's also hard for a model to tell what's going on in the middle of the ocean. Showers and thunderstorms can block the view of a satellite, so a model may start out with a fuzzy impression of the real atmosphere. Right now there's no magic way to tell which hurricanes are bogus and which are real.

Forecasters play it safe by looking at several models that cover the same time period. If a hurricane develops in each model, it's probably for real. But if it only shows up in one model, then forecasters recognize it as a figment of that computer model's bogus imagination.

The Weather Notebook is a production of the Mount Washington Observatory a member supported research and educational organization. Find out more at mountwashington.org.