A sharp weather contrast is setting up across the country this week. Critical fire weather conditions are developing across parts of the central and southern High Plains, while repeated Pacific storms continue to bring heavy mountain snow to the West. Meanwhile, a strengthening system will spread snow and mixed precipitation from the Northern Plains to New England, and a potential coastal storm this weekend could bring wind and rain — or snow — to parts of the Mid-Atlantic and Northeast. Temperatures will swing dramatically as much colder air settles into the East by early next week.