By the numbers

The wide range of predictions:

Named storms

12-20

Hurricanes

7-10

Major hurricanes

3-6

(111+ mph)

Sources: Tropical Meteorology Project, the United Kingdom Weather Service, the Weather Channel, AccuWeather.com, N.C. State and Penn State

The National Hurricane Center releases its 2013 hurricane season predictions today. Don’t bother to hold your breath: It will be a busy season.

That’s what Tropical Meteorology Project hurricane guru William Gray says. So do N.C. State University forecast whiz Lian Xie, the United Kingdom Weather Service, the Weather Channel, AccuWeather.com and the research group at Penn State University, among others.

And if they’re right, 2013 would be the 13th year of the past 17 to have more hurricanes than the long-term average.

The divining rods for all these computer forecasts are the same trends in atmospheric and ocean conditions.

The only differences in results between these programs tend to be in the number of predicted storms.

“Anticipate (the Hurricane Center) to go for an above-normal number of named storms,” said Mark Malsick, S.C. Climate Office severe weather liaison.

The federal announcement will kick off the “official” June-November hurricane season, the time when tropical cyclones are likely to form in the Atlantic. The ocean-spawned storms can kill and cause millions of dollars damage.

In Charleston, the greatest threat of the worst storms tends to run from August through September.

“Call me old-fashioned, but I don’t put too much stock on these pre-season predictions and prefer to focus on the tropics day to day,” Malsick said.

The various forecast numbers are down somewhat from the actual totals of 19 named storms for each of the past three years.

The moderating factors are relatively cooler tropical ocean temperatures and El Nino possibly sticking up its head. El Nino, or cold Pacific water, tends to impede hurricanes in the Atlantic.

But an El Nino cooling hasn’t begun yet, and the forecast is for conditions to remain neutral into the late summer.

Maybe the most significant computer guess for the Lowcountry is Lian Xie’s. The N.C. State team predicts seven to 10 hurricanes forming in the Atlantic basin, with two of them not going into the Gulf of Mexico or the Caribbean Sea.

That means they would be headed toward us. It’s been seven years since a major hurricane made landfall in the United States — something that hasn’t happened before since record-keeping started. Nobody expects this trend to continue for long.

“A wild season is on the way, and the ‘major hit drought’ on the U.S. coast should end,” said meteorologist Joe Bastardi of WeatherBell. “In fact, multiple major hits are likely this year with (some conditions) favoring the East Coast, as in the 1950s.”

Hurricanes Irene and Sandy have raked the East Coast the past two years.

It’s worth pointing out that in the 1950s, three hurricanes and a tropical depression made landfall in South Carolina.

Two of them were powerful storms: Hurricane Hazel in 1954 hit near Little River, and Hurricane Gracie in 1959 hit near Beaufort.

Gracie was as strong as the devastating Hugo in 1989. Hazel hit in mid-October. On the brighter side, a year after two “pre-season” storms formed, the Atlantic basin is quiet now, thanks to strong shear winds.

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