Where are the weather balloons launched from? We had a large, white balloon with alot of string tethers land in our yard here in Pittsboro on a Saturday afternoon in June.

MIKE MOSS SAYS:       Rose,        The National Weather Service directly operates 69 release sites in the continental U.S., 13 in Alaska, 9 in the Pacific and one in Puerto Rico, for a total of 92. In addition, data exchange agreements with other countries provide access to atmospheric soundings from almost 900 sites worldwide, the bulk of which are located in the Northern Hemisphere. They are all launched at the same time twice a day, at 0000 and 1200 hours Universal Time.

I can't be sure from your description if you found one of these standard radisosondes, but if so there are several possibilities for a site of origin, depending on what the direction and speed of winds aloft were in the hours before the radiosonde landed. However, as you indicated it was found in Chatham County, it most likely was launched from Greensboro, but other possible launch points include Morehead City, Roanoke VA, Charleston SC, and Atlanta. The sondes can be mailed in for reuse by enclosing them in an attached tyvek envelope and placing them in any mailbox for postage-free return to the government.