Short Story. The balloon is lost near Shrewsbury, PA. But we are sure (now after post processing) that we know where it is within about an acre.
See: http://aprs.org/balloons.html
Premature burst (or separation) caused the payload to descend at over 5000 feet per minute slowing to 4000'/min (nearly 50 MPH straight down)at last posit. We did not know this at the time, and wasted our time searching the track 1/2 mile beyond the last data point assuming the much slower parachute design rate of 600'/min.
When we got home, post processing revealed the high descent rate and the more likely spot much closer to the last known position. Also the high impact is why it probably ceased transmitting.
Also we were looking for a balloon and parachute in the trees, not (as it turns out) for the football sized Styrofoam box (mostly covered in black duct tape!) somewhere on the ground in the underburush. We would not have noticed that between other occasional trash in the area.
Contact info is on the balloon.
Bob, WB4APR
410-293-6417