Officials say the Grasshopper Fire has burned more than 83,600 acres and is now 20 percent contained.  The fire remained active Tuesday along the northeastern and eastern edges, pushed by gusty winds.  The northeast corner has reached Hix Road, while the eastern edge is near Elliott Road.  Firefighters held the northern perimeter along Forest Road 4421 and continued strengthening lines elsewhere.  Activity has moderated along the southern and southwestern edges.  Crews today are focused on strengthening control lines, particularly on the eastern side, ahead of stronger winds this afternoon and unstable weather expected this weekend.  Air operations will continue as conditions allow.  The Southern Area Blue Incident Management Team has replaced a California team and has joined the Oregon State Fire Marshal in a unified command of the fire, with a team from Australia and New Zealand also embedded at the fire.  Additional crews and engines from California arrived Tuesday night.  About 1,832 firefighters are assigned to the fire.  A community meeting is planned for Thursday at 6 p.m. at Dufur School.