The Louisville area is under a winter storm warning, as the collision of two storm systems is expected to bring significant snowfall overnight.Forecaster Joe Ammerman with the National Weather Service in Louisville says the original forecast was for three to four inches of snow, but that has been increased to four to six inches of snow.“Snow shouldn’t begin until after eight or nine o’clock tonight, so we’re looking at the overnight period with heavy snow falling after two o’clock in the morning and during the morning rush hour as well," he says.After a short tapering off, Ammerman says the area could see another inch during the afternoon hours. He says temperatures after the snow event will continue to be cold, at least for a few days.