PORTLAND, Ore. ( KOIN) — In advance of a storm that could drop feet of snow in the Cascades, the National Weather Service has issued a Winter Storm Warning that goes into effect Friday morning and lasts through Saturday for elevations in the Cascades above 3,000 feet.

There are changes on the way for how the National Weather Service issues a winter storm warning. The old criteria issued warnings based on how much snow fell in a certain time span. The new criteria are based on total snowfall in a certain area.

Several storms will blast the Northwest over the next few days, courtesy of multiple atmospheric rivers that are forecast to dump heavy rain and feet of snow across the region. "A series of storms will come ashore in the Northwest late this week,

Multiple storms are making a beeline for the Pacific Northwest, which will result in a prolonged period of heavy precipitation and gusty winds at times. Over the next week, a widespread 4 to 8 inches of rain is predicted for lower elevations and as much as 15 to 20 inches in the mountains.