Weather Academy: Cone of Uncertainty

Published: Aug. 30, 2021 at 8:31 AM CDT
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MONROE, La. (KNOE) - All month long, we’ve been learning about hurricanes. And last week, we built our own hurricane-proof house. But today, we’re going to be learning about the cone of uncertainty.

The cone of uncertainty is something you might be used to seeing, especially during hurricane season. It’s a forecast product put out by the National Hurricane Center, and it’s full of helpful information. Meteorologists use it to help give an example of where exactly the storm will be tracking.

The cone stretches from about 12 hours out to 120 hours out. At each forecast point along the system’s lifecycle, we forecast for the intensity and the location of the storm’s center. That’s important. The cone is only tracking where the middle of the storm is going to go. The impacts of that storm can still be felt outside of our cone.

You’ll also never see the cone extend past five days. That’s because once we get five days out, our forecast becomes a little bit too uncertain to track for sure. But once we’re within the 12 hours to 120 hours, we have a pretty good idea of where exactly this hurricane will be heading.

Five days out is also when our cone is the widest at the top. This gives us the most wiggle room of where precisely the eye will be tracking. At 12 hours out, the cone is much smaller and much thinner at only 27 miles across. How wide the cone is at each point in this forecast is based on our historical error of how well our forecasts have done in the past. So 2021′s track is based on the error from 2016 to 2020.

Now the good news is we keep getting better at forecasting hurricanes thanks to advancements in technology. The National Hurricane Center has become so good at forecasting where these systems will be tracking that the storm’s eye stays within our cone two-thirds of the time. That means the top of the cone of uncertainty has shrunk about 100 miles in the last ten years.

But again, the rain bands of the hurricanes stretch farther out than the cone. The impacts of the hurricane can still affect areas miles outside of the cone. That’s why it’s important to listen to meteorologists when they say what impact you can expect with these systems because even in the rain bands, we can see tornadoes, strong winds, and heavy downpours, as well as flash flooding.

We hope you’ve enjoyed learning about hurricanes this month with us. Make sure you tune in next week because Meteorologist Sheena Martin will be kicking off our next topic by talking about high and low-pressure systems. Remember, if you’ve tried any of our experiments at home, we would love to see photos!

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