NASA - National Aeronautics and Space Administration

On the morning of September 15, 2004, Hurricane Ivan continues to barrel towards the southeastern United States with maximum sustained winds hovering around 140 miles per hour. NASA continues to peer inside these storms in search of clues about Ivan's intensity as it nears landfall.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite popped Ivan's hood to see the heat engine that drives hurricane. Inside scientists can see the rain structures inside hurricanes, helping them study the physics behind these storms. Scientists use this information in models to help improve intensity forecasting.



Images Right: TRMM scan of Hurricane Ivan taken September 15, 2004. Blue represents area where at least 0.25 inches of rain fell in 1 hour. Green represents area where at least 0.5 inches of rain fell in 1 hour. Yellow represents area where at least 1.0 inches of rain fell in 1 hour. Red represents area where at least 2.0 inches of rain fell in 1 hour. Click refresh to reset animation. For stills or high resolution images Credt:NASA

Forecasting a hurricane's intensity is extremely challenging. "The National Hurricane Center is pretty good at predicting the path of a hurricane." says Marshall Shepard, Researcher with NASA's Goddard Space Flight Center. "But predicting when a hurricane is going to intensify from category 2 to 4 or weaken from a category 5 down to 1 is much more difficult."

Image Left: The colors on the track represent the storm's intensity.
Tropical depression is purple.
Tropical storm is blue.
Category 1 hurricane is blue-green.
Category 2 is green.
Category 3 is yellow.
Category 4 is orange.
Category 5 is red.
Credt:NASA