A ‘powerful and dynamic’ storm blitz will leave parts of the US under inches of snow as the nation braces for a late winter ‘whiteout’. The freak storm system will sweep central and northern states this week pushing temperatures 30F below than normal, experts warn. Strong winds and blizzards through the coming days have sparked warnings for to avoid all but emergency travel. Drifting snow threatens to bury parts of the region under an eight-inch winter carpet, despite this week being the first of spring. It comes as two winter storms–Ronnie and Sawyer–join forces through the end of March to un…