In a fast-paced hurricane season with 14 named storms already forming, a quirky trend has emerged: About half have traveled far to the north or east into territory they seldom go.
Hurricane Leslie hit Newfoundland as a tropical storm last week. Shortly after that, Hurricane Michael petered out near Nova Scotia. Earlier this month, Hurricane Kirk churned so far north it almost reached Iceland, and in June, Hurricane Chris formed east of Maine and turned toward Newfoundland.
Then there was Hurricane Gordon, which charged east and peppered the Azores -- 970 miles from Portugal -- with winds and rain. And now Hurricane Nadine is forecast to take the same route.
The paths are unusual, experts say, because most tropical systems take a westerly course toward the Caribbean or the U.S. coastline.
The reason: A persistent area of low-pressure near the U.S. coast is deflecting storms north. And the jet stream, a fast-moving river of air over the North Atlantic, is pulling others east.
Those conditions have benefited the U.S. East Coast, including Florida, said Gerry Bell, lead hurricane forecaster for the National Oceanic and Atmospheric Administration. He noted some storms also turned north in 2010 and 2011.
"This is the third year in a row that there's a stronger-than-average trough over the East Coast," he said. "That tends to steer systems away from our coast."
So far this year, Isaac is the only hurricane to travel far enough west to hit the United States. After veering into the Gulf of Mexico, it struck Louisiana in late August, soaking Florida along the way.
Jeff Masters, chief meteorologist of Weather Underground, an online weather site, said that, to some extent, exceptional drought conditions over the Midwest can be credited for turning storms north.
The drought has been so
prolonged, it worked to create a low-pressure area, "which has acted to steer hurricanes away from the East Coast," he said.
Experts say atmospheric patterns can remain in place for months, if not years, prompting storms to move in the same direction. That's what happened in tumultuous 2005, when numerous storms aimed at the United States and Mexico, among them hurricanes Dennis, Emily, Katrina, Rita and Wilma.
Sometimes even storms of the same name can take similar paths, said Phil Klotzbach, a Colorado State University climatologist.
"The last hurricane to impact the Azores prior to Hurricane Gordon in 2012 was Hurricane Gordon in 2006," he said. "How weird is that?"