How are Things Looking in the Tropics?

Tropics are Generally Quiet on 7-29-15  (Source: NOAA)

Aside from getting off to an early start with Tropical Storm Andrea forming in May, the 2015 hurricane season has been rather quiet.  Although there have been three named storms so far, they have all been relatively weak and short-lived.  Most people are unaware of Tropical Storm Claudette which formed last week off the Mid-Atlantic Coast because it quickly moved out to sea and dissipated.  None of this season’s three tropical storms reached hurricane intensity.

June and July are typically among the quieter months of the hurricane season, with activity picking up in August.  However, current conditions in the tropical Atlantic Ocean remain inhospitable for tropical storm formation.  Sea surface temperatures aren’t as warm as they usually are this time of year and there has been an increased amount of wind shear – winds that change direction with height in the atmosphere.  Tropical storms and hurricanes weaken when they encounter wind shear or cooler water. 

Scientists generally attribute these unfavorable conditions to a developing El Nino event.  “El Nino” refers to the warming of the water in the central and eastern equatorial Pacific Ocean.  NOAA is forecasting a 90% chance that the developing El Nino will last through the 2015-2016 winter season.  El Nino has global repercussions and contributes to a busier than average hurricane season in the Eastern Pacific Ocean – west of Mexico.  Meanwhile, during an episode of El Nino, the Atlantic Ocean sees a below average number of tropical storms and hurricanes.

However, a below average number of tropical storms and hurricanes doesn’t mean none of them will be destructive or deadly.  For example, 1992 was a quieter than average hurricane season in the tropical Atlantic Ocean but was the year of Hurricane Andrew.  Andrew developed in August and was one of the strongest and most damaging hurricanes in U.S. history.
 
From 1995 through 2012, all but two seasons saw an above average number of named storms in the Atlantic Ocean.  Although NOAA will soon issue its August update to their hurricane season forecast, all indications are that the Atlantic Ocean will see its third consecutive below average hurricane season.