WASHINGTON (AP) — Federal forecasters predict this winter may paint the U.S. in stripes of different weather: Warmer and drier than normal in the south, and colder and wetter than usual in the far north.

The National Weather Service winter outlook , issued Thursday, gets murky in the nation's middle belt, with no particular expectation for trends in temperature or precipitation.

Still, some nasty storms might make the winter there memorable, said Mike Halpert, deputy director of the weather service's Climate Prediction Center.

The major driver of the winter forecast is a budding La Nina, a cooling of the central Pacific that warps weather worldwide and is the flip side of the better-known El Nino, Halpert said.