Already gearing up for polar vortex 2.0? Not so fast, federal forecasters say.

A repeat of last year’s exceptionally frigid and snowy winter east of the Rocky Mountains is “unlikely,” according to the National Oceanic and Atmospheric Administration. A national winter outlook issued Friday by the federal agency’s Climate Prediction Center shows above-average temperatures favored in the western U.S., Alaska, Hawaii and New England.

From October to December, parts of the U.S. Northeast and Southeast and all of the West Coast and Alaska will see above-average temperatures, while slices of Texas, New Mexico and Arizona will see below-average temperatures. If the warming persists, it could make 2014 the world’s hottest year ever recorded, NOAA climatologist Jake Crouch said last month.

Earlier this year, states east of the Rockies experienced temperatures so mild that attendance at public pools across the region fell dramatically. The primary cause was a persistent dip in the Northern Hemisphere’s jet stream -- the current of air that hovers in the atmosphere.

“We’re seeing a big uptick in all sorts of extreme events, and most of them are connected to the unusual pattern in the jet stream,” said Jennifer Francis, a research professor at Rutgers University in New Jersey.

El Niño, an ocean-atmospheric phenomenon in the tropical Pacific Ocean that affects global weather patterns, may still develop this winter and could help smooth out this dip, lowering the chances of another polar vortex sweeping through the east come wintertime. Federal forecasters estimate a 67 percent chance of an El Niño episode by the end of the year.

While strong El Niño events often pull moisture into California during the winter months, this El Niño is expected to be weak, offering little help for drought recovery.

“Complete drought recovery in California this winter is highly unlikely,” said Mike Halpert, acting director of NOAA’s Climate Prediction Center.