MIAMI The 2013 Atlantic hurricane season is still on track to be "above normal" but "extreme levels of activity" are less likely, the top U.S. government climate agency said on Thursday.
The National Oceanic and Atmospheric Administration said the six-month season, which began on June 1 and will soon enter its peak, could still be "very active" and spawn 13 to 19 named storms, six to nine of which were expected to become hurricanes.
In an earlier pre-season forecast, issued in May, NOAA had predicted up to 20 named storms and said as many as 11 of them could become hurricanes. At that time it warned that the hurricane season could be "extremely active."
In its May forecast, NOAA predicted as many as six major hurricanes at Category 3 or above. It trimmed that total to no more than five in its latest forecast.
The average Atlantic hurricane season brings 12 tropical storms with six hurricanes, including three major hurricanes.
"The updated outlook is similar to the pre-season outlook issued in May, but with a reduced expectation for extreme levels of activity," NOAA said.
It cited a reduced probability that this year will see a development of the La Nina weather phenomenon as one of the reasons for the slightly reduced forecast.
La Nina is associated with cooler than normal water temperatures in the Equatorial Pacific Ocean and can cause reduced wind shear over the tropical Atlantic Ocean that further strengthens the hurricane season.
Another factor behind the slightly more benign forecast was the lack of any hurricanes in July and more variability in wind patterns over the tropical Atlantic, NOAA said.
Last year's season spawned 19 tropical storms, 10 of which became hurricanes. Two of them grew into major hurricanes, including Superstorm Sandy, which NOAA said caused more than 200 deaths and more than $50 billion in damage in the United States.
(Reporting by Tom Brown; editing by Andrew Hay)