With cooler than normal ocean temperatures and a thick layer of Saharan dust over the tropics, the Atlantic Ocean is quiet as hurricane season begins. (NOAA/RAMMB/CIRA)

With hurricane season beginning June 1, Colorado State University has released an updated seasonal hurricane forecast that drops the number of storms expected.

The group now predicts a total of 14 named storms, six hurricanes and two major hurricanes — category 3 or stronger. This forecast is very close to what we consider an average season — 12 named storms, 6.5 hurricanes and two major hurricanes.

Although climate models continue to suggest a low chance of an El Niño developing, the Atlantic is cooler than normal. The pattern of sea surface temperature anomalies observed during May is the opposite of what would be associated with an active Atlantic hurricane season, with cool anomalies in the deep tropics and far northern Atlantic and warm anomalies in the subtropics.


The pattern of this past month’s sea surface temperature anomalies is not typically associated with active hurricane seasons. (NOAA)

Other skillful indicators this time of the year are the strength of the Bermuda High and the magnitude of the equatorial upper-level winds in the Pacific.

Years with conditions similar to this include 1986, 2001, 2012 and 2014. Tracks of all 29 hurricanes recorded during those seasons are shown here (only three of them reached Category 4 intensity: Gonzalo 2014, Iris 2001, and Michelle 2001).


Tracks of the 29 hurricanes that occurred during the four analog years (1986, 2001, 2012, 2014.)

Seasonal hurricane forecasting was pioneered at CSU by Bill Gray in the early 1980s.  Now there are literally dozens of agencies and universities making such forecasts. Since 2006, Phil Klotzbach has been the primary author of the famous forecasts. This year’s marks the 35th anniversary of these forecasts. A key message from Klotzbach is “regardless of the seasonal forecast, it only takes one storm to make it an active season for you!”

This year’s list of hurricane names was first used in 1982, and every six years since then.  Names that have been retired from it over the decades include Gilbert (’88), Joan (’88), Keith (’00), and Sandy (’12).  “Sara” was chosen to replace Sandy.

With Alberto, this season is the fourth consecutive one to have a preseason named storm. Keep in mind though that the official start and end dates of hurricane season were never meant to contain all of the activity, just the vast majority.

At the National Hurricane Center, new products will become operational this season. The well-received “time of arrival” graphics will transition from experimental to operational this year, and the forecast “cone of uncertainty” shrinks slightly again as track errors have been reduced over the past five seasons. Storm surge watches and warnings will continue, as well as the practical ability to issue advisories on “potential tropical cyclones.”

NHC provides a detailed list of their updates ready for action in 2018.


An example of the “time of arrival” graphic becoming operational this year. This was for Hurricane Irma in 2017. (NOAA/NHC)