Paper on measurements of extreme wind speeds and updrafts in hurricanes published in Monthly Weather Review

Dropsondes are instruments released from Hurricane Hunter aircraft that measure temperature, humidity, and wind speed as they fall to the ocean. Since they were first used in 1997, more than 12,000 have been dropped into tropical cyclones (hurricanes and typhoons) around the world. All of these observations are studied to find those with the fastest wind speeds and updrafts measured in tropical cyclones. Sixty-four dropsondes that measured wind speed faster than 90 ms-1 (200 mph), and 169 with updrafts faster than 10 ms-1 (22 mph), were found. Study of these extremes is important because it may help us understand how very strong winds reach the surface during landfall of very strong storms such as Hurricane Andrew.

Important Conclusions:

1. Very strong updrafts are common in intense tropical cyclones, and frequently occur in the same locations as very strong wind speeds. These extreme updrafts and wind speeds are sometimes found very close to the ocean surface.

2. The region within tropical cyclones where very strong updrafts and wind speeds primarily occur is predictable. They occur mainly in the eyewall (the ring of strong storms and high winds surrounding the eye), and mainly to the left of the direction of the wind that flows over the top of the storm.
3. These results can help to predict where the strongest winds may occur at the surface when a tropical cyclone makes landfall, and also to improve the safety of Hurricane Hunter aircraft and crews who fly into these powerful storms.

The paper can be found at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-15-0313.1.

 

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