Report: Hurricane Michael Upgraded to Category 5 at Landfall

April 19, 2019 · 1 comment

2018’s devastating Hurricane Michael struck the Florida panhandle at Mexico Beach and Tyndall Air Force Base in October at Category 5 intensity with 160 mph winds, the National Hurricane Center announced Friday. That’s 5 mph higher than Michael’s wind estimate of 155 mph at the time of landfall.

GOES-16 Pseudo-color image or Hurricane Michael at 1730 UTC October 10, 2018. (Courtesy: NOAA NESDIS)
GOES-16 Pseudo-color image or Hurricane Michael at 1730 UTC October 10, 2018. (Image courtesy: NOAA NESDIS)

 

In its post-storm tropical cyclone report, released the same day, NHC stated it culled an abundance of wind data measurements not available in real-time to add the 5 mph to Michael’s wind intensity. The data came from aircraft reconnaissance, ground observations, satellite intensity estimates, surface pressures, and Doppler radar velocities from Eglin Air Force Base and the NWS in Tallahassee. The report goes in-depth with the data, explaining the observations and identifying those that were believable—a 152 knot (175 mph) aircraft wind measurement at 8,000 feet in the southeast eyewall that yields a surface wind of 137 knots (158 mph)—versus those that were suspect—a 152 knot (175 mph) surface wind measured by the stepped frequency microwave radiometer (SFMR) instrument aboard a different aircraft, deemed too high based on experience with such intense winds in hurricanes Irma, Jose, and Maria in 2017.

The upgrade makes Michael only the fourth Category 5 hurricane to hit the United States, joining a small, elite group of monster landfalling storms that include Hurricane Andrew (1992, 165 mph winds), Hurricane Camille (1969, 175 mph winds), and the Labor Day Hurricane (1935, 185 mph winds). Andrew plowed into South Florida, Camille landed on the Mississippi coast, and the Labor Day Hurricane devastated the Florida Keys.

A realty building destroyed by Hurricane Michael's winds on the east of Panama City, Florida.
A realty building destroyed by Hurricane Michael’s winds on the east side of Panama City, Florida.
(Photo courtesy: Chris Cappella [AMS])

Hurricane Michael roared ashore on October 10 as the strongest hurricane on record to strike the Florida Panhandle, with a storm surge around 14 feet above ground level, destroying Mexico Beach and much of Tyndall AFB, while tearing apart homes and businesses in Callaway, just inland, as well as in the eastern side of Panama City. Sixteen people died directly from the hurricane due to storm surge flooding and the intense winds, which blew down entire forests in the panhandle and destroyed crops across southern Georgia. Wind damage extended into the Carolinas.

Very few surface observations of the hurricane’s intense winds were made at landfall. The highest gust was 139 mph measured by an anemometer at Tyndall AFB before it failed. Two coastal monitoring program towers measured 129 mph and 125 mph, substantially lower than the upgraded wind speed at landfall. One of the towers was knocked over before the peak winds struck, and the other was outside the hurricane’s core. NHC notes that the sites “were likely not optimally located to sample the maximum winds, which is typical during landfalling hurricanes.”