(WAFB) - After every hurricane season finishes, the National Hurricane Center (NHC) takes a look back at each storm to determine if a storm needs to be upgraded or downgraded.
This past season, Hurricane Michael was upgraded from a Category 4 hurricane, to a Category 5 hurricane as it made landfall in the Florida Panhandle. Hurricane Michael’s landfall wind speed was increased from 155 mph to 160 mph, making it the fourth Category 5 hurricane to strike the United States.
In addition to a post season review, the NHC is reviewing every tropical cyclone to ever exist in the Atlantic Basin beginning in 1850.
In the 1980′s, the NHC began reanalyzing previous hurricane seasons. The project continues to this day and has concluded storm history from 1850 to 1960 with 1961 to 1965 set to come out this summer.
Dr. Christopher Landsea is the chief researcher of the project. “What we try to do is avoid you know looking at the political ramifications of it and just look at the science. What is the science telling us this particular hurricane was. So whether we upgrade it or downgrade it, we really try to divorce ourselves from the implications,” Dr. Landsea said.
In addition to the 110-year history of 1850 to 1960, the project also reanalyzed Hurricane Camille in 1969 and Hurricane Andrew in 1992 because only four Category 5 hurricanes have ever hit the United States.
NHC wanted a definitive study to find out which storm was the worst in United States history.
“What we try to do is get all the measurements that they took at the time," Dr. Landsea said. "Whether it was radar, aircraft, or station observations, and then reassess it into today’s light of: well if we have these data, what do they mean to us now?”
What the reanalysis found was that Louisiana could no longer stake claim to the having experienced the strongest U.S. landfall in history with Hurricane Camille in 1969. The Labor Day hurricane that hit the Florida Keys in 1935 was upgraded, while Hurricane Camille was downgraded swapping out the top two spots.
"The item that we relied upon most was the central pressure, that is the lowest pressure right in the eye of the hurricane and we were able to find a couple of additional pressure measurements that were taken back in 1969 during the hurricane,” Dr. Landsea added.
Hurricanes Andrew in 1992 and Michael last season, in 2018, were upgraded to round out the top four.
In the history of the project, 20 hurricanes have been upgraded by category while 29 hurricanes have been downgraded in category. An additional 67 saw slight changes that did not affect the hurricane’s category.
“It’s always a bit of a puzzle game. We are putting together a jigsaw puzzle where we’re always missing pieces and so being able to figure out what the whole thing is, is always a challenge,” according to Dr. Landsea.
All four of the strongest landfalling U.S. hurricanes have moved into or through the Gulf of Mexico.
The storm reanalysis of biggest interest to Louisiana, set to be released this summer, is Hurricane Betsy of 1965.