A SIGMET is a concise description of the occurrence or expected occurrence of specified en route weather phenomena which may affect the safety of aircraft operations. SIGMETs are intended for dissemination to all pilots in flight to enhance safety. SIGMETs are issued by the responsible MWO as soon as practical to give notice to operators and aircrews of potentially hazardous en-route conditions.
AC 00-45G 6.1 Significant Meteorological Information (SIGMET) (page 6-1)
An AIRMET is a concise description of the occurrence or expected occurrence of specified en route weather phenomena which may affect the safety of aircraft operations, but at intensities lower than those which require the issuance of a SIGMET. AIRMETs are intended for dissemination to all pilots in flight to enhance safety and are of particular concern to operators and pilots of aircraft sensitive to the phenomena described and to pilots without instrument ratings. AIRMETs are issued by the responsible Meteorological Watch Office (MWO) to give notice to operators and aircrews of potentially hazardous en route conditions.
AC 00-45G 6.2 Airmen’s Meteorological Information (AIRMET) (page 6-20)
Also see AIM 7−1−6. Inflight Aviation Weather Advisories (page 7-1-8) for additional information
AC 00-45G 6.1 Significant Meteorological Information (SIGMET) (page 6-1)
AC 00-45G 6.2 Airmen’s Meteorological Information (AIRMET) (page 6-20)
Also see AIM 7−1−6. Inflight Aviation Weather Advisories (page 7-1-8) for additional information