GM1 to AMC1 ATS.TR.305(a);(b) Scope of flight information service

INFORMATION FOR DEPARTING AIRCRAFT — METEOROLOGICAL CONDITIONS Significant changes in this context include those relating to surface wind direction or speed, visibility, RVR or air temperature (for turbine-engined aircraft), and the occurrence of thunderstorm or cumulonimbus, moderate or severe turbulence, wind shear, hail, moderate or severe icing, severe squall line, freezing precipitation, severe mountain waves, sandstorm, dust storm, blowing snow, tornado or waterspout.