A Pacific storm swinging into California this weekend may then spread a mess of snow and ice into parts of the Midwest and Northeast, kicking off the first full week of February early next week. After one of the coldest Midwest outbreaks in a generation, the jet stream pattern will undergo a fundamental change. Instead of taking a nosedive out of Canada into the Great Lakes and Northeast, the jet stream will take a southward plunge in the western U.S. by the weekend. This will push a potent storm to the West Coast this weekend that will work its way into the Plains, Midwest and Northeast early next week.