That trace of dust you’ve been breathing is one of your best friends during hurricane season.
It’s been blown 4,000 miles from the Saharan desert, and those plumes of dry air help knock down tropical cyclones as they cross the Atlantic.
The dust storms, though, have peaked and are waning. Monsoons are blowing off West Africa near the Cape Verde Islands into a warmer than the normal tropical ocean. Water that hot might as well be a turbine turning the winds that become hurricanes, and the powerful trans-Atlantic tropical cyclones are the storms are most likely to threaten the Lowcountry.
The Atlantic off the Southeast “is a real hotbed of fuel for tropical systems with the right conditions. Almost any storm that favors atmospheric development could rapidly intensify over these waters,” said meteorologist Shea Gibson of WeatherFlow.
This is the heart of the tropical season, which peaks in early September. After a freak hurricane in January, a tropical storm in May and two in June, the Atlantic settled down through July, a not-so-unusual turn of events. No forecaster expected that to last.
Hurricane specialists on Saturday were keeping an eye on two monsoon storms in the tropical ocean. Neither was expected to strengthen into a tropical cyclone. But the timing and the strength of the storms suggest the Cape Verde period is getting underway.
“The Atlantic hurricane season is typically quiet until mid-August; there is a sharp jump in activity beginning in the third week of August. By the third week of August, the African monsoon is in high gear, spitting out lots of tropical waves that can act as the seeds of hurricanes,” said Jeff Masters, Weather Underground meteorology director.
So far, not all of the conditions are lining up for a “busy” Cape Verde period. La Niña winds, which don’t shear hurricanes, have been predicted to rise during the season. They haven’t yet. Conditions remain hostile to cyclones in the eastern Atlantic development area for Cape Verde storms, said Mark Malsick, S.C. Climate Office severe weather liaison.
“There really isn’t any guidance with any skill at this juncture to say when the season gets more active,” Malsick said. “Our only fallback is climatology that shows hurricanes and tropical cyclone activity begins to ramp up in August, peaks 10 September and peters out 10 November. Whether the Atlantic got the climatology memo, we don’t quite know yet.”
But Malsick, too, points to sea surface temperatures as the most worrisome condition out there for the Southeast coast.
“My only concern is that the western North Atlantic (off South Carolina) remains abnormally warm, much like last year. This sets the stage for limited reaction time to a storm that is able to develop quickly offshore,” he said.
A weak if anything La Niña, the relatively cooler eastern Atlantic and a relatively cold northern Atlantic should put dampers on cyclones developing, said Phil Klotzbach of the Tropical Meteorology Project. The project’s seasonal forecasts are a benchmark in the field. Its mid-season update will be issued in the coming week, Klotzbach said. But the overall, large-scale signals continue to suggest the near-average Atlantic hurricane season that the project and other forecasters predicted in the spring.
But, he said, “even an average Atlantic hurricane season is going to seem quite active given the past three quiet seasons that we’ve had.”
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