***Meaning*** :: <u>SIG</u>nificant <u>MET</u>eorological Information ***Additional Information***: - Impacts all aircraft - Issued - Unscheduled releases - Lasts 4 hours - From [[MWO]] - Issued for - Severe or greater turbulence (SEV TURB) - Severe icing (SEV ICE) - Widespread dust storm (WDSPR DS) - Widespread sandstorm (WDSPR SS) - Volcanic ash (VA) ***Related To***: [[Inflight Aviation Weather Advisories]] #acronym