After more than three decades of weather forecasting on Baltimore TV, WMAR's Norm Lewis announced his retirement on-air Tuesday during the 5 p.m. newscast. Lewis is the third longtime WMAR broadcaster to leave the station recently. The other two are Mary Beth Marsden and Terry Owens, who left earlier in the month after they took a buyout offer from the station's owner, E.W. Scripps. Lewis' last day is Dec. 22.