air report special

air report special (ARS)

Special observations made by aircraft operating on international air routes whenever severe turbulence or severe icing is encountered; moderate turbulence, hail, or cumulonimbus clouds are encountered during transonic or supersonic flight; or other meteorological conditions for example the other en route weather phenomena specified for SIGMET [significant meteorological information] messages are encountered that, in the opinion of the pilot-in-command, may affect the safety or markedly affect the efficiency of other aircraft operations.