 The National Weather Service in the Quad Cities has issued a tornado warning for southern Buchanan County in northeastern Iowa, northeastern Benton County in east central Iowa, northwestern Linn County in east central Iowa, until 5.30 p.m. At 4.51 p.m., tornado-producing storms were located along a line extending from near Lime Creek County Park to near Benton County Fairgrounds, moving east at 35 miles per hour.