Superstorm Sandy as it strikes the East Coast in late October 2012.
Superstorm Sandy as it strikes the East Coast in late October 2012. (Space Science and Engineering Center, University of Wisconsin-Madison)

An early 2013 hurricane season forecast is calling for a busy summer and fall, with a nearly 50 percent chance of a major storm striking the U.S. East Coast.

Forecasters at Colorado State University on Wednesday predicted 18 named storms would form in the Atlantic Ocean, about six more than normal. That would be one fewer than in 2012, though.


They expect nine of those storms to become hurricanes, and four of those hurricanes to reach "major" storm status.

The forecast paints a picture of a chaotic storm season, with storm strength and frequency expected to be well above normal.

"We anticipate an above-average Atlantic basin hurricane season due to the combination of an anomalously warm tropical Atlantic and a relatively low likelihood of El Niño," the forecasters wrote.

Atlantic hurricane season runs from June 1 through Nov. 30. To become a named storm, a tropical cyclone must have maximum sustained winds of 39-73 mph. Hurricanes must reach 74-110 mph, while major hurricanes have winds of 111 mph or greater.

The report, released annually by the Tropical Meteorology Project at Colorado State, calls for a 72 percent chance that a major storm will strike U.S. coastline. The average for the last century is 52 percent.

Such chances for the East Coast are 48 percent, compared to an average over the last century of 31 percent.

Most forecasters had predicted a near-normal season in 2012, with about a dozen named storms. It appeared an El Niño might form, and high wind shear associated with that climate phenomenon generally disrupts tropical cyclone formation.

But that El Niño never materialized, and still isn't expected to this year.

Those conditions allowed for the busy 2012 season, which included many storms that strengthened enough to warrant names but did not severely affect land. But, of course, the devastation of Hurricane Sandy in New Jersey and New York showed that it only takes one storm to punctuate a storm season.

Other hurricane season forecasts from the National Hurricane Center, AccuWeather.com and other sources are expected in the coming months.