MIAMI (AP) — U.S. government forecasters expect a near-normal Atlantic hurricane season, after three relatively slow years. But they also say climate conditions that influence storm development are making it difficult to predict how many hurricanes and tropical storms will arise over the next six months.
The National Oceanic and Atmospheric Administration's outlook Friday called for a near-normal season with 10 to 16 named storms, with four to eight hurricanes and one to four "major" ones with winds reaching 111 mph and up.
The long-term season averages are 12 named storms, with six hurricanes and three major ones.
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The Atlantic hurricane season officially starts June 1, but tropical weather got a head-start this year: Hurricane Alex made an unseasonable debut in January over the far eastern Atlantic, and the National Hurricane Center says an area of low pressure between Bermuda and the Bahamas could be brewing into something bigger Friday or Saturday.
While they can't predict whether any storm will strike the U.S., and more tropical storms are expected than in the last three years, NOAA officials said significant variables are at play.
It's unclear whether a decades-long high-activity era for Atlantic hurricanes has ended, said Gerry Bell, lead seasonal hurricane forecaster with NOAA's Climate Prediction Center. Meanwhile, El Nino is dissipating while La Nina looms for the season's peak from August through October.
El Nino is the natural warming of parts of the Pacific Ocean that changes weather worldwide. That tends to reduce hurricane activity in the Atlantic, while La Nina tends to increase it.
The active storm era associated with warm Atlantic temperatures and stronger West African monsoons began in 1995, but recent hurricane seasons showed shifts toward a cooler phase marked by colder waters and a weaker monsoon, Bell said.
Each era can last 25 to 40 years, and it might take years to determine whether the transition has happened, Bell said.
The last transition to a less active hurricane era happened in the 1970s, without the data and computer models that forecasters have now. "We're watching it for the first time with very new eyes," Sullivan said.
NOAA 2016 Atlantic hurricane seasonal outlook calls for near normal hurricane season. https://t.co/sRjyOCRCXJ pic.twitter.com/gvskBiGEdU
— Natl Hurricane Ctr (@NWSNHC) May 27, 2016