A big change in the weather pattern will bring temperatures plummeting for much of the East late this week. Temperatures will drop anywhere from 5 to 15 degrees below average. Highs will reach only the 40s and 50s for millions on Friday. Saturday morning, much of the Southeast could see its first frost or freeze of the season, with lows in the 30s for cities like Atlanta, Nashville, Raleigh, Jackson and Charleston. Here’s all the details.