The 2018 Atlantic hurricane season, which officially concludes on Friday, was more active than forecasters predicted.
The season will be remembered most for hurricanes Florence and Michael, which caused significant damage in the southeastern U.S.
Yucatan has gone unscathed and Pemex reported no disturbances to their oil operations in the Gulf of Mexico. In Mexico, most hurricane activity was on the Pacific side, particularly Willa in October.
“The 2018 season fell within NOAA’s predicted ranges in our pre-season outlook issued in late May. However, the overall season was more active than predicted in the updated outlook issued in early August,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “Warmer Atlantic Ocean temperatures, a stronger west-African monsoon and the fact that El Nino did not form in time to suppress the season helped to enhance storm development.”
The season produced 15 named storms, including eight hurricanes. Two of those were “major” hurricanes — Category 3, 4 or 5. An average season has 12 named storms, six hurricanes, and three major hurricanes.
For the fourth consecutive year, hurricane activity began prior to the official June 1 start of the season, with Tropical Storm Alberto forming near the Yucatan Peninsula on May 25. Alberto made landfall in northern Florida and traveled as far north as the Great Lakes as a tropical depression.
A record seven named storms — Alberto, Beryl, Debby, Ernesto, Joyce, Leslie and Oscar — were classified as subtropical at some point. The previous record of five subtropical storms occurred in 1969.
A subtropical storm is a named storm that has tropical and non-tropical characteristics. All subtropical storms this season eventually transitioned into a tropical storm, with three (Beryl, Leslie and Oscar) eventually becoming hurricanes.
The 2018 hurricane season was the first since 2008 to have four named storms active at the same time — Florence, Helene, Isaac and Joyce.
Hurricane Florence caused catastrophic flooding in portions of North and South Carolina. Several river forecast locations in the Carolinas approached or broke their record flood level in the days and weeks following the hurricane. It took two to three weeks for many river locations to fall below flood stage, and the final river crested one month after Florence made landfall.
Hurricane Michael, at a Category 4 intensity, was the strongest hurricane on record to strike the Florida panhandle. It was the third-most-intense hurricane to make landfall in the continental U.S. on record in terms of central pressure (919 mb) and the fourth-strongest in terms of maximum sustained winds at 155 mph.
Storm-by-storm forecasts from NOAA’s National Hurricane Center were aided by the high-resolution imagery from NOAA’s new GOES-East satellite and the Global Forecast System (GFS) model, which produced accurate forecasts of landfall location and timing for both hurricane Florence and Michael.