A new surge of cool air is moving across the Midwest and is forecast to expand into the Northeast and much of the southern United States, east of the Rockies. Residents from the Dakotas to the Appalachians who have delayed reaching for jackets and long sleeves may need them with this latest push of Canadian air. The core of the cool air will follow a front moving through the Midwest and Plains into Friday night, then advance more slowly across the Atlantic coast and from Louisiana to Texas