2013 Atlantic Hurricane Season Outlook
Posted: Wednesday, June 19, 2013
An average Atlantic hurricane season begins on June 1st; this year’s season got a quick start on June 5 with the formation of Tropical Storm Andrea, which is relatively early compared to recent years but not as early as last year when two storms formed in May. Earlier today, the second named storm of the season, Barry, formed in the southern Gulf of Mexico, although Barry will be a short lived tropical storm, expected to quickly make landfall in Mexico and dissipate. An average Atlantic hurricane season has about 10 named storms, 6 hurricanes and 2 major hurricanes, taken from the 1950-2000 averages. Since 1995, however, tropical cyclone activity in the Atlantic has noticeably increased, with a high frequency of above average hurricanes seasons in recent years. Last year was more active than anticipated with19 named storms and 10 hurricanes, although despite the high number of storms, last year’s hurricanes were mostly weak aside from Michael and Sandy, the only two major hurricanes which both briefly held that intensity for 6-12 hours.
Typically, El Niño years have decreased activity in the Atlantic, with increased activities during La Ninas. An El Nino was forecast to develop last year, and did initially develop during the summer, but rapidly collapsed by the fall with neutral-negative ENSO conditions observed during last winter; although it was not officially a La Nina, it was the 3rd winter in a row with negative ENSO. So far, sea surface temperatures have warmed in the equatorial Pacific, but with an absence of an El Nino at this time, and a generally neutral ENSO is likely for this year’s hurricane season. This year is generally favored for at least slightly above average activity; compared to last year, the hurricanes that do form are likely to be more intense and closer to the coast, with an increased risk of tropical cyclones affecting the US coast, especially in the southeast US and the Gulf of Mexico.
With the formation of Andrea and Barry, two named storms have already been used this year. Taking these two storms into consideration and the anticipated increase in activity later in the summer, this year’s forecast is for above average activity, with 14 to 18 named storms, 6 to 9 hurricanes, and 3 to 4 major hurricanes. An update to this outlook will be posted on August 6th.