Atlantic Hurricanes: Version 2016

Visible Satellite Image of the Tropical Atlantic Ocean   (Source: NASA GOES Project)

A lot of people start to think about the upcoming hurricane season during the second half of April.  That’s because the hurricane season begins on May 15 in the eastern Pacific Ocean (off the west coast of Mexico) where it runs through November 15.  Hurricane season begins on June 1 in the Atlantic Ocean and runs through the end of November.  NOAA data indicates an average Atlantic hurricane season has approximately 12 named tropical storms, 6 hurricanes with 3 of those becoming “major” hurricanes based on the 30-year period ending in 2010.  A “major” hurricane is a Category 3 or higher storm on the Saffir-Simpson Hurricane Wind Scale with sustained winds of at least 111 mph. 

Although NOAA hasn’t issued their forecast for the 2016 Atlantic hurricane season yet, several other groups have issued their seasonal forecasts.  Colorado State University’s forecast for the upcoming season is for a near average season with 12 named tropical storms, 5 of which become hurricanes and 2 major hurricanes.  North Carolina State University’s seasonal forecast calls for 15 – 18 tropical storms, 8 to 11 hurricanes and 3 to 5 major hurricanes.  AccuWeather is also calling for a slightly busier than average season with 14 tropical storms, 8 hurricanes and 4 major hurricanes.

Each group looks at the same key factors when preparing their seasonal forecast.  The phase of “ENSO” or El Nino Southern Oscillation is a key factor in seasonal hurricane forecasts.  During a strong El Nino event, wind shear in the tropical Atlantic tends to be higher and sea surface temperatures tend to be cooler.  These factors contribute to making a less favorable environment for tropical storms and hurricanes.  Meanwhile, conditions tend to be more favorable for tropical storms and hurricanes in the eastern Pacific Ocean during a major El Nino event. 

During one of the strongest El Nino’s on record last year, the eastern Pacific Ocean had a significantly busier than average hurricane season.  Most will also recall that the 2015 hurricane season in the Atlantic Ocean was quieter than average.  However, the significant El Nino event of the past year has begun to fade.  That helps create a big wildcard in this season’s hurricane forecast as scientists wait and to see if La Nina develops.  An episode of La Nina is characterized by cooler than average water temperatures in the tropical East Pacific.  That helps reduce wind shear the tropical Atlantic while sea surface temperatures also tend to be warmer than average during an episode of La Nina.

The 2013 and 2014 Atlantic seasons were also quieter than average and that shows while the presence El Nino or La Nina loom large over a hurricane season, they aren’t the only factors that influence how busy the tropics can be.  For example, a large portion of the North Atlantic Ocean currently has colder than average sea surface temperatures and that could also influence the upcoming hurricane season.  So, the best thing for the general public to do now is to pay attention as the start of hurricane season draws closer.  If you live in an area prone to tropical storms and hurricanes, it’s important to have an evacuation plan in place should your area be threatened.  The next tropical storm that develops in the Atlantic Ocean will be given the name “Bonnie” since a rare January hurricane named “Alex” already developed.