Hurricane season starts Wednesday, but Bonnie can’t wait.
Bonnie is a tropical storm forming off the coast of Georgia. The National Hurricane Center announced Saturday morning that Bonnie will make landfall late this evening or early Sunday with South Carolina squarely in her crosshairs. Georgia can expect heavy rain, a surge of water and winds gusting above 35 miles per hour for much of the Memorial Day weekend.
It may be a bumpier-than-usual hurricane season, which runs June 1 through Nov. 30. A dozen tropical storms, five turning into hurricanes, are predicted from Maine to Florida.
Meteorologists at Colorado State University say two of the hurricanes could be at a minimum category 3 with wind speeds topping 111 mph. And there’s a 30 percent chance one of those suckers makes landfall.
The predictions, as well as forecasts by federal agencies and other universities, aren’t too different from previous years. What worries scientists, though, is the expected late summer or early fall convergence of troubling weather trends.
The El Nino weather pattern, which has largely tamped down wild weather over the Atlantic Ocean, is ending. Its replacement, La Nina, promises more tumultuous weather and should be in place by September or October.
Warmer temperatures — 2015 was the hottest year ever recorded — will likely fuel nastier storms. A warmer Atlantic Ocean will also help turn tropical storms into hurricanes. And rising sea levels will further punish coastlines once a storm hits.
While scientists can’t conclusively say that climate change leads to more hurricanes, they do predict that a warming planet will lead to more ferocious storms.
“Every time we get a hurricane or a flood people ask, ‘Was that caused by climate change?’ ” said Marshall Shepherd, the director of the atmospheric sciences program at the University of Georgia. “But that’s not the right question to ask. A better question is, ‘Are events like that becoming more frequent or more intense because of climate change?’ ”
No major hurricane — category 3, 4 or 5 — has hit the Atlantic coast since Wilma in 2005. Georgia hasn’t suffered a major direct blow in more than a century. The state’s worst hurricanes came in August 1881, 1893 and 1898. Credit is due to Georgia’s relatively short — 100 miles long — coast and a coastline that curves inward and, supposedly, out of harm’s way.
A wicked flurry of cyclonic activity in the 2000s, particularly in Florida, has given way to largely smooth sailing the past decade. Sandy slammed New Jersey and New York in 2012, but it was barely a hurricane by then. (A rising sea and high tides caused most of the damage.)
El Nino has kept us calm. Unusually warm waters in the Pacific Ocean generate upper-level winds over the Atlantic Ocean. Strong wind shear rips apart hurricanes or keeps them from forming.
El Nino, though, is ending. La Nina, with lesser winds incapable of deterring hurricanes, promises a wild ride. The National Weather Service’s Climate Prediction Center says there’s a 75 percent chance that La Nina will be in full force this fall and winter.
“Typically, the results are drier and warmer conditions in the Southern U.S.,” said Shepherd, who hosts “Weather Geeks” on the Weather Channel. “We’re transitioning toward a more favorable environment for tropical storms.”
Air and water temperatures, worldwide, are already on the rise. 2016 is expected to be warmer than 2015, which was warmer than 2014. The National Oceanic and Atmospheric Administration says average sea-surface temperatures in 2014 were a record 1.03 degrees above the 20th century average.
A Florida State University professor, joined by a South Korean colleague, reported last year that warmer ocean waters, due to climate change, are likely causing stronger, yet fewer, hurricanes. Wind speeds in tropical cyclones increased 3 mph between 1984 and 2012, the authors found.
Tom Knutson, a research meteorologist with NOAA’s Geophysical Fluid Dynamics Laboratory at Princeton University, cautions against making historical correlations between climate change and hurricanes.
“Over the (past) century, of course, global temperatures have really risen in a pronounced way, and we can attribute a lot of that warming, with a good deal of confidence, to human influence,” he said. “But we’re not seeing the same kind of smoking gun, if you will, at the landfalling of hurricanes. We can’t really confidently say we can detect a clear human influence on Atlantic hurricanes.”
Ever-warmer water and air, though, will produce a 4 percent increase in a hurricane’s wind speed by century’s end, Knutson predicts.
“We will actually get more, very intense category 4 and 5 storms,” he said. “But there will be fewer storms overall.”
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