The Atlantic hurricane season (including the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico) runs from June 1 to November 30, with August to October the usual period of peak activity. On May 25, 2017, the Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA) released its outlook for the 2017 Atlantic hurricane season. The news release on the forecast is available online at http://www.noaa.gov/media-release/above-normal-atlantic-hurricane-season-is-most-likely-year. The full forecast report is available online at http://www.cpc.ncep.noaa.gov/products/outlooks/hurricane.shtml.
The outlook is a collaboration of the Climate Prediction Center, the National Hurricane Center, and the Hurricane Research Division, all within NOAA.
According to the news release, forecasters predict a 45 percent chance of an above-normal season, a 35 percent chance of a near-normal season, and only a 20 percent chance of a below-normal season. The outlook also estimated a 70 percent likelihood of 11 to 17 named storms (winds of 39 mph or higher), of which 5 to 9 could become hurricanes (winds of 74 mph or higher), including 2 to 4 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher). On average from 1966 through 2009, the Atlantic basin has averaged 11 named storms, of which six become hurricanes, with two major hurricanes, according to the National Hurricane Center’s “Tropical Cyclone Climatology” Web page, http://www.nhc.noaa.gov/climo/. One named storm already occurred in 2017: Tropical Storm Arlene, in April.
NOAA’s full outlook report makes the following cautions about predicted storm numbers: The outlook is “a general guide to the expected overall nature of the upcoming hurricane season; [the outlook] is not a seasonal hurricane landfall forecast, and it does not predict levels of activity for any particular region. Hurricane disasters can occur whether the season is active or relatively quiet. It only takes one hurricane (or tropical storm) to cause a disaster. Residents, businesses, and government agencies of coastal and near-coastal regions are urged to prepare for every hurricane season regardless of this, or any other, seasonal outlook.”
During the season, reports on individual storms as they occur will be available at http://www.nhc.noaa.gov/?atlc. When storms are completed, reports on individual 2016 storms (including tracks) will be available online at http://www.nhc.noaa.gov/data/tcr/index.php?season=2017&basin=atl.
National Hurricane Center averages for the Atlantic season for the period 1981-2010 are 12 named storms, 6 hurricanes, and 3 major hurricanes. Here are the numbers for the past five years:
2016 – 15 named storms, 4 of which became hurricanes, including 3 major hurricanes;
2015 – 11 named storms, 4 of which became hurricanes, including 2 major hurricanes;
2014 – 8 named storms, 6 of which became hurricanes, including 2 major hurricanes;
2013 – 13 named storms, 2 of which became hurricanes;
2012 – 19 named storms, 10 of which became hurricanes, including 1 major hurricane.
Also on May 27, 2016, NOAA issued its outlook for the Eastern Pacific and Central Pacific basins. That report is available online at http://www.cpc.ncep.noaa.gov/products/Epac_hurr/Epac_hurricane.html. For both basins, NOAA estimates an 80-percent chance of a near- or above-normal season. The eastern Pacific outlook calls for a 70-percent probability of 14 to 20 named storms (6 to 11 hurricanes, including 3 to 7 major hurricanes). The central Pacific outlook calls for a 70-percent probability of 5 to 8 tropical cyclones (tropical depressions, tropical storms, and hurricanes).
National Hurricane Center’s graph of the tracks of Atlantic tropical storms and hurricanes in 2016, accessed at http://www.nhc.noaa.gov/data/tcr/index.php?season=2016&basin=atl.