The polar vortex could return to freeze the Midwest, Northeast

COLLEGE PARK, Md., Oct. 16 (UPI) -- Last year's winter weather misery could be priming for a repeat performance, with a potential for the frigid polar vortex to make an unwelcome return.

While most experts agree that it's unlikely the U.S. will see low temperatures to surpass last year's record-shattering cold, the blast of Arctic air that tormented the Midwest and East last winter could head down again.

"I think, primarily, we'll see that happening in mid-January into February but again, it's not going to be the same type of situation as we saw last year, not as persistent," expert long-range forecaster Paul Pastelok said in Accuweather's annual winter forecast Thursday.

Pastelok said the South might also face a particularly wet winter season, even ice storms, while the polar vortex distortion pushes icy temperatures further north, dumping heavy snows on the I-95 corridor, particularly near New York and Philadelphia.

"The cold of last season was extreme because it was so persistent," he said. "We saw readings that we haven't seen in a long time: 15- to 20-below-zero readings."

The Farmer's Almanac explains the high likelihood of a weak El Niño event -- a band of warm weather pushing up from South America in the Pacific -- could force colder air into the Midwest and East even if the West Coast enjoys warmer temperatures.

The Climate Prediction Center forecasters give a 67 percent chance that El Niño will develop by the end of the year, although by Oct. 9, the ocean and atmospheric events necessary have not yet occurred.

El Niño's increased moisture, meanwhile, will likely ease the intense drought gripping California, although its relative weakness means it's unlikely to completely reverse the drought.

While some of the Arctic weather may return this year, CPC meteorologists say the large-scale patterns that made last year so miserable are "really unlikely to occur."