Hurricane Arthur moves up the East Coast on July 3,...

Hurricane Arthur moves up the East Coast on July 3, 2014 in this photo provided by the National Oceanic and Atmospheric Administration. Credit: Getty Images / Handout

Forecasters on Wednesday called for a below-normal Atlantic hurricane season but emphasized that coastal residents shouldn't relax.

"A below-normal season doesn't mean we're off the hook," said Kathryn Sullivan, administrator of the National Oceanic and Atmospheric Administration. "As we've seen before, below-normal seasons can still produce catastrophic impacts to communities."

Sullivan, at a news conference in New Orleans, cited several seasons that were predicted to be below normal but still produced some major storms -- including 1992, when seven named storms developed but the first, Category 5 Hurricane Andrew, devastated South Florida.

For the upcoming hurricane season, which officially runs from June 1 to Nov. 30, NOAA is predicting a 70 percent likelihood of six to 11 named storms (winds of 39 mph or higher), of which three to six could become hurricanes (winds of 74 mph or higher), including zero to two major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher).

If a below-normal season is likely (70 percent), there also is a 20 percent chance of a near-normal season, and a 10 percent chance of an above-normal season, forecasters said.

Officials at the New Orleans news conference, including the city's mayor, Mitch Landrieu, urged those living in areas prone to hurricanes to "hope for the best and prepare for the worst."

A major factor in harnessing this hurricane season, as weather models indicate, is a likely moderate-to-strong El Nino event.

Gerry Bell, lead seasonal hurricane forecaster with NOAA's Climate Prediction Center, said El Nino, a climate cycle in the Pacific, already is "affecting wind and pressure patterns, and is forecast to last through the hurricane season."

Bell also said "El Nino may also intensify as the season progresses, and is expected to have its greatest influence during the peak months of the season."

Another calming factor is more normal sea surface temperatures in the tropical Atlantic.

Bell said in the past "warmer waters would have supported storm development."

The NOAA prediction marks the third outlook that suggests a less frenetic hurricane season.

Earlier, researchers at Stony Brook University, where a new prediction model has been developed, and Colorado State University forecast a below-average Atlantic hurricane season.

The Stony Brook model is tailored to predict the number of tropical cyclones that could hit New York State in a given season. Its forecast is for a 19 percent probability, with 43 percent being the average, for one or more storms hitting New York State, according to Hye-Mi Kim, assistant professor in the School of Marine and Atmospheric Sciences.

Kim, along with professors Edmund K.M. Chang and Minghua Zhang, developed the new forecast approach; their article on the model was posted in April on Weather and Forecasting, an online journal of the American Meteorological Society.

In an annual report released last month, researchers at Colorado State said this will be "one of the least active seasons since the middle of the 20th century."

Seven named storms are predicted, three of which are expected to become hurricanes, with one reaching major strength as a Category 3, 4 or 5, according to the school's Tropical Meteorology Project. That's compared with the climatological average of 12 named storms, 6.5 hurricanes, two of them major.

Still, as lead author Philip J. Klotzbach has warned coastal residents before, "It takes only one landfall event near you to make this an active season."

The Colorado State prediction is based on a study of 60 years of historical data, with this year's conditions, so far, similar to those leading into five seasons with below-normal activity, including that of 2014, said Klotzbach, a research scientist.

With Patricia Kitchen