Annular Adrian becomes the first major hurricane of the Eastern Pacific hurricane season

[phantom power]

I recall one of the hurricanes of the infamous 2005 season surviving for a while in 50-knot wind shear and thinking WTF? Wonder if it was annular.

Hurricane Adrian put on an impressive bout of rapid intensification Thursday, intensifying into the season's first major hurricane in the Eastern Pacific. Adrian is the globe's 6th Category 4 or stronger tropical cyclone of the year. Adrian is expected to remain far enough offshore the coast of Mexico to not pose a threat to that country. Gradual weakening is likely through the weekend, since Adrian will be tracking over cooler ocean waters. Adrian's decay will be slower than usual for a hurricane, since it has become what is called an annular hurricane. Annular hurricanes feature a large eye surrounded by a very thick eyewall, with no spiral rain bands. The very thick eyewall makes annular hurricanes resistant to weakening due to wind shear, dry air, or cool waters. Annular hurricanes are rare; only 3% of all Eastern Pacific tropical cyclones become annular, and 1% of all Atlantic ones.

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1822