SIGMET format discriminator indicating which of the three distinct SIGMET message formats this object represents.
CONVECTIVE
NONCONVECTIVE
INTERNATIONAL
SIGMET format discriminator indicating which of the three distinct SIGMET message formats this object represents.
CONVECTIVE- Domestic convective SIGMET (CONUS thunderstorm advisories)NONCONVECTIVE- Domestic non-convective SIGMET (CONUS turbulence, icing, volcanic ash, dust/sandstorm)INTERNATIONAL- International ICAO format SIGMET (Alaska, oceanic FIRs, international airspace)