On September 2, 2007, a National Oceanic and Atmospheric Administration Hurricane Hunter airplane flew into Hurricane Felix when it was a category-5 hurricane north of Venezuela. The aircraft measured wind speed of 163 kt (188 mph) at the ocean surface and an upward wind speed of 60 kt (69 mph), the fastest upward wind ever encountered by an airplane in a hurricane. This caused the plane to rise almost 300 m (1000 ft) and then fall the same distance again in about one minute. The study looks at the data obtained during the flight to try to explain what happened.
- The dangerous event in Hurricane Felix was similar to one in Hurricane Hugo in 1989. The plane was flying higher in Felix than in Hugo. The upward wind was stronger in Felix than in Hugo, but the Hugo feature was much larger than in Felix.
- The dangerous event may have been caused by a very small-scale swirl (vortex) like the one measured in Hurricane Isabel.
- It has been believed that these extreme events are most likely to happen (and put Hurricane Hunter airplanes in danger) in hurricanes that are strengthening quickly (rapid intensification). This study suggests that they are most likely when the hurricane is at the end of rapid intensification.
- Further study is needed to learn whether these events are important in forecasting hurricane intensity.
You can access the paper at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-16-0364.1.