Not one, but three potential storms threaten to usher in the busiest phase of the Atlantic hurricane season later this month, courtesy of warm ocean temperatures.
The season — which runs from June to November — has already seen above-average activity this year. Storms with the capacity to cause the most damage are statistically more likely to develop from late August to early October, originating from thunderstorms and low pressure from the Caribbean Sea to the west coast of Africa.
“The tropical Atlantic is currently the third warmest for this time of year since 1950, so that’s bullish for activity,” said Todd Crawford, chief meteorologist at The Weather Company in Andover, Massachusetts.
Warm ocean temperatures are the lifeblood of hurricanes. Meanwhile, wind shear and dry air from the Sahara, both of which can slow storm development, aren’t as pronounced at this time. Atlantic storms can wreak havoc with U.S. natural gas and oil production facilities in the Gulf of Mexico, while Florida, the world’s largest orange juice producer behind Brazil, is also vulnerable.
So far this year, seven storms have been named in the Atlantic, two of which have become hurricanes.
Over the long-term average, the second hurricane doesn’t usually form until Aug. 28 and the seventh storm doesn’t appear until Sept. 16, according to the National Hurricane Center. Storms get names when their winds reach 39 miles (63 kilometers) per hour and reach hurricane strength at 74 mph.
The late Bill Gray, who pioneered seasonal hurricane forecasts, would actually walk through the offices of Colorado State University’s forecasting team on Aug. 20 and ring a bell to let his colleagues know that the peak of the season had arrived. Storms that develop at this time of the year have historically been the biggest — Category 3 or more on the five-step Saffir Simpson scale — and caused the most problems.
“It is rare to have a major, land falling hurricane that didn’t form from a tropical wave that didn’t come off the coast of Africa,” said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan.
At the beginning of August, Colorado State University raised its seasonal forecast to 16 named storms from 15 a month before. The National Oceanic and Atmospheric Administration upped its outlook to a range of 14 to 19 from 11 to 17 in May.
An additional 10 storms, six hurricanes and three major systems have been seen on average from now until the season’s end over the past 15 years, said Crawford. “Those levels look quite reasonable, if not a touch low, going forward,” he said.
Masters said he isn’t worried about what’s in the Atlantic just now. Hurricane Gert will eventually lose its tropical power even as it makes its way toward Ireland and the U.K. early next week. The three potential storms “don’t raise alarm bells with me,” he said.
The system near the Lesser Antilles has an 80 percent chance of becoming a storm in the next two days, the National Hurricane Center said. A U.S. Air Force Reserve Hurricane Hunter aircraft will fly into the system Thursday to take a closer look. The second system has a 60 percent chance of becoming a storm in five days and the third, near Cabo Verde, has a 40 percent chance.
Crawford isn’t so ready to dismiss them since the last one which is closest to Africa “will probably have the best environment for development and may become our first major hurricane of the year later in the month as it moves toward the U.S.”
The current burst of activity is also being helped by a global pattern called the Madden-Julian Oscillation, which is making conditions even more conducive for storms to develop, Masters said. That will probably fade by early September, when there could even be a bit of a lull.
“As we move into September, we expect a less favorable environment for development, so that peak of the season may not be as ‘peaky’ as usual,” Crawford said.
In the near term, none of these systems threaten the U.S. The same pattern that’s been bringing milder weather to the eastern U.S. “effectively steers approaching storms out to sea like Gert,” Crawford said.
The three possible storms might cause shippers trouble as they transport oil around the Atlantic and Gulf of Mexico, said Phil Flynn, senior market analyst at Price Futures Group in Chicago.
While a more powerful season looms, there’s at least one bright side: None of these tropical systems will blot out the sky for next Monday’s solar eclipse, Masters said.