According to Eye of the Storm, the latest data from the reconnaissance plane indicates that Dennis now a Category 4:
Recon finds 131 knots in the northeast quadrant, do the usual 10% deduction [from flight-level to ground-level winds] and convert to mph and you get 136 mph. Ladies and gentleman we have a category four hurricane in the Gulf of Mexico in July. Insane.
For those who are unclear on that equation, it goes like this:
131 knots at flight level x
0.90 (estimated percentage of flight-level winds felt at the surface) =
118 knots at surface level x
1.15 (knots-to-mph conversion) =
136 mile-per-hour winds at surface level
The threshold for Category 4 status is 131 mph. The NHC always rounds to the nearest multiple of five, so that effectively means that a hurricane must be at 135 mph in order to be a Cat. 4. I expect that’s exactly where they’ll put this hurricane as of the next advisory.
The next intermediate advisory is due out at midnight EST. I think I’ll wait for that before going to bed (unless there’s a pre-advisory update indicating the upgrade to Cat. 4, which is possible).
