SIGMET

SIGMET aeronautical warning information

SIGMET information description

SIGMET is information concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations. SIGMET contains information about:

thunderstorms (TS) or thunderstorms with hail (TSGR) that are poorly recognizable (OBSC - obscured), embedded in other clouds (EMBD), frequent (FRQ) or lined up into squall line (SQL),
severe turbulence (SEV TURB),
severe icing (SEV ICE),
severe icing caused by freezing precipitation (SEV ICE (FZRA)),
severe mountain wave (SEV MTW),
heavy dust (SEV DS) or sandstorm (SEV SS),
tropical cyclones (TC),
volcanic ash (VA) or
radioactive cloud (RDOACT CLD).

SIGMET information is issued in the form of abbreviated open language for the relevant FIR. Validity period is max. 4 hours (in case of SIGMET information about VA up to 6 hours).

Example of SIGMET information:
WSOS31 LOWW 020717
LOVV SIGMET F04 VALID 020730/020930 LOWW-
LOVV WIEN FIR SEV ICE (FZRA) FCST AT 0730Z WI N4857 E01534 - N4846 E01704 - N4749 E01733 –
N4717 E01506 - N4732 E01410 - N4814 E01606 - N4857 E01534 SFC/3000FT STNR WKN=

Whereas SIGMET information contains the spatial distribution of dangerous phenomena in the form of text, in this image it transformed into a graphical form on the map (as shown above). The occurrence of a dangerous phenomenon in the FIR area is highlighted by a changed colour of the relevant FIR and the definition of a specific area of its occurrence (coloured bounded area). The content of the SIGMET information (phenomenon, validity, vertical range, movement and intensity) is displayed in the assigned text field (explanations of the layout of the information are in the figure at the bottom right).
If SIGMET information it is not possible to express graphically, the original text of the information is displayed in a reserved field on the right side of the image.

Image with the SIGMET information is always updated at the beginning and/or end of the validity of the SIGMET information issued for FIR Slovakia (LZBB), Poland (EPWW), the Czech Republic (LKAA), Austria (LOVV), Hungary (LHCC) and Ukraine (UKLV), i.e. the timeliness of SIGMET information from other areas needs to be verified in another way, e.g. by phone at MWO Bratislava: +421 2 48 57 42 63.