Weather key to skydive attempt
8 October 2012 Last updated at 11:03 BST
Near perfect weather will be required for Austrian adventurer Felix Baumgartner to try to make the highest ever skydive.
The 43-year-old aims to beat the current record of 102,800ft (31.3km) when he lifts off in a balloon this week from Roswell, New Mexico.
His meteorologist Don Day told our correspondent Jonathan Amos that the size of the balloon means very calm winds will be needed to get the bid under way.