Central Wisconsin residents may have been viewing what is called a “vapor cone” Saturday afternoon.  Several reports were phoned in when people noticed something in the sky which looked like a weather balloon.  The problem is, weather balloons apparently aren’t launched until evening.  A vapor cone is caused when an aircraft flies at or near the speed of sound and a cloud is formed.  Observers may have been looking at the sun’s rays shining through the vapor left behind by a military aircraft.  Stevens Point and Plover are said to be on the flight path for aircraft from Volk Field, but military officials haven’t confirmed their jets were in the area.