FLORIDA, United States, Friday April 21, 2017 – She didn’t stick around for very long, but Arlene yesterday became the first storm of the 2017 Atlantic hurricane season – more than a month before the official start.
The subtropical depression that had been lingering between Bermuda and the Azores strengthened into a depression tropical storm yesterday morning before becoming a storm later in the day. But less than 24 hours later, it was no longer a tropical system.
In its last advisory on the system around midday, the National Hurricane Centre (NHC) in Miami said Arlene had merged with a large extratropical cyclone. Post-tropical cyclone Arlene is now forecast to dissipate later today.
— NHC Atlantic Ops (@NHC_Atlantic) April 21, 2017
The out-of-season Arlene was never any threat to land. However, it may raise questions about whether predictions of a below average hurricane season this year may be off the mark.
According to AccuWeather hurricane expert Dan Kottlowski, they aren’t.
“The development of Arlene is an anomaly and will have no important bearing on how the 2017 Atlantic hurricane season unfolds,” he said.
“The development of a tropical storm from a non-tropical system in the Atlantic is rare but can happen given special atmospheric conditions during the spring and fall seasons.”
This is the third consecutive year a system has formed in the Atlantic before the official start of the June 1–November 30 hurricane season.
— NHC Atlantic Ops (@NHC_Atlantic) April 20, 2017
AccuWeather had said this season will likely produce about 10 named storms, half of which could development into hurricanes – three of them large enough to be considered major hurricanes.
Colorado State University hurricane researcher Phil Klotzbach is predicting 11 named storms, four hurricanes and two major hurricanes of Category 3 strength or higher.
Both predictions base the expected reduced activity on a reappearance of El Nino – a weather phenomenon in the Pacific Ocean that impacts global weather patterns. El Nino, which warms the waters of the Pacific Ocean, blocks the development of hurricanes in Atlantic basin.