You can detect lightening using ground based detectors: http://en.wikipedia.org/wiki/Convective_storm_detection#Lightning_detection http://en.wikipedia.org/wiki

You can detect lightening using ground based detectors: http://en.wikipedia.org/wiki/Convective_storm_detection#Lightning_detection http://en.wikipedia.org/wiki/Convective_storm_detection#Ligh... This specific delay though was caused by convective clouds being too close to the launch. This was probably determined with either ground based radar, or visible/IR images from satellites.