SIGMET reports are warnings in abbreviated plain language issued for Skopje FIR. Sigmet report gives concise description of the occurrence or expected occurrence of phenomena as thunderstorms, severe turbulence, severe icing and volcanic ash, which may affect the safety of overflight operations. SIGMETs are not regular reports and are only issued when specified phenomena occurs or is expected to occur.

An example of SIGMET report

LWSS SKOPJE FIR  SEV TURB  FCST WHOLE FIR FL150/200  STNR  NC =