The National Hurricane Center (NHC) upgraded Hurricane Michael to Category 5 on the Saffir-Simpson Scale after it completed and released its post storm analysis on Friday. NHC does a post storm analysis of every tropical cyclone in its area of responsibility after the end of the hurricane season. The maximum sustained wind speed at the time of landfall in northwest Florida of Hurricane Michael, which was given originally as 155 m.p.h. (250 km/h), was increased to 160 m.p.h. (260 km/h) after the post storm analysis. Hurricane Michael becomes one of only four hurricanes to make landfall in the U.S. as a Category 5 hurricane. The other Category 5 hurricanes to hit the U.S. were the Labor Day Hurricane which hit the Florida Keys in 1935, Hurricane Camille which hit Mississippi in 1969 and Hurricane Andrew which hit south Florida in 1992.
The National Hurricane Center prepares a Tropical Storm Report on every tropical cyclone in its area of responsibility and those reports are available on NHC’s web site. J. L. Beven II, R. Berg and A. Hagen were the authors of the Tropical Cyclone Report on Hurricane Michael. They explain in the Tropical Cyclone Report how they arrived at the intensity of Hurricane Michael at landfall. They analyzed aircraft data including flight level winds and SMFR intensities. They did an analysis of the Dopper wind velocities observed by the WSR-88D radar at Eglin Air Force Base. They also considered available data on the surface winds and pressures and satellite derived estimates of the intensity of Hurricane Michael. Based on analysis of all of that information, they concluded that the intensity of Hurricane Michael when it made landfall in northwest Florida was 160 m.p.h. (260 km/h). Their full Tropical Cyclone Report on Hurricane Michael is available on NHC’s website at https://www.nhc.noaa.gov/data/tcr/AL142018_Michael.pdf.