Omens good for hurricane season

Winds, rain, ragged surf and rip currents tormented the Lowcountry in July 2014 as a tropical cyclone became Hurricane Arthur while passing offshore.

Shear winds are blowing in from the Pacific. Seas aren’t so hot in the Atlantic tropics. That’s a double whammy for hurricanes — again — as the season stirs.

Federal forecasters on Wednesday joined an assortment of academic and private forecasters saying conditions suggest the number of tropical cyclones that form this summer will be average or slightly below average. The Climate Prediction Center and its computers are calling for six to 11 named storms, three to six becoming hurricanes and zero to two big ones.

That’s no real surprise. As far back as winter, El Nino winds and “normal” sea surface temperatures were boding a “calmer” season. Warmer seas feed and strengthen tropical cyclones, and El Nino is a Pacific Ocean warming trend that strengthens “shear winds” in the Atlantic that tear apart cyclones that do form.

The hurricane season officially begins June 1 and runs to November 30. The Cape Verde period in which powerful storms are most likely to threaten the Lowcountry runs from early August into October. But tropical cyclones and devastating hurricanes have formed before and after those dates.

In fact, for the Lowcountry, the season made its first pass with Tropical Storm Ana in early May.

The same wind and sea conditions spurring this year’s forecast were in place in 2014, although the predicted rise of strong El Nino conditions last year never really happened.

El Nino is currently weak to moderate. But it’s expected to intensify as the season goes on and be at its peak during the late summer peak months for hurricanes, said Gerry Bell, the center’s lead season forecaster. It’s already affecting wind patterns, he said.

The persistent winds and not-so-hot seas indicate that a more active period for hurricanes that started in 1995 might be chilling out, suggested both the National Oceanic and Atmospheric Administration and Weather Underground forecaster Jeff Masters. The storms tend to cycle through more-and-less active periods of 20 years or more.

But the refrain remains the same: Devastating hurricanes can and do form during “calm” seasons and “cooler” periods. It only takes one powerful storm landfall to make for a very bad year locally.

Reach Bo Petersen at 937-5744, @bopete on twitter or Bo Petersen Reporting on Facebook.