WASHINGTON — Federal weather forecasters are watching for signs that this winter could be colder and snowier than usual across the northern United States.

The National Weather Service's Climate Prediction Center last week, meaning conditions are becoming favorable for a weather pattern that typically brings harsher winters.

La Niña happens when ocean waters in the Pacific get cooler than normal. La Niña typically brings cooler, wetter conditions to the northern U.S. while causing warmer, drier weather in the southern states. The pattern can also affect the jet stream, leading to more active storm systems in some regions.

El Niño is the warm phase of the same meteorological phenomenon.

The weather pattern could develop sometime between now and early winter, forecasters said. They estima

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