The Weather Notebook: Hurricane Food

Hurricane Food
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Dave Thurlow, Host

If you want to feed a hurricane give it plenty of warm water. Hi, I'm Dave Thurlow for the Mount Washington Observatory and this is the Weather Notebook.

Typically the ocean surface needs to be at least 79° to keep a tropical storm or hurricane cranking. Usually, by September of each year water temperatures across the Gulf of Mexico are well into the 80's. But, sometimes hurricanes run out of gas even as they travel over these steamy waters. Why? Because the warm water is often too shallow.

The summer sun only warms about the top 100' of the tropical sea. A hurricane could plow up this surface layer easily and bring up cool water from well below. That pulls the plug on the hurricane's power source. Which is, the energy in warm water.

However, a hurricane sometimes runs into a deeper pool of warm water that extends down as far as 300'. There's enough energy there for even the most voracious storm.

Forecasters have started using a new tool to measure how deep the Sun warmed surface layer extends into the ocean. This tool is a satellite-mounted radar that actually measures the height of the ocean. Water expands as it heats up so a deep warm layer will cause the ocean surface to bubble up just a few inches. But, the radar can detect it.

This summer the radar system is watching a warm pocket of water, several hundred miles wide moving slowly across the Gulf of Mexico. It may feed a hurricane, and it may not. But, in any event, the warm Gulf waters will once again feed the worries of folks along the Gulf Coast.

Contributing writer Bob Hensen.

Funding provided by the National Science Foudation

Underwritten by Subaru, the Beauty of All Wheel Drive.