Section 7. Flight Advisories
(SIGMET/WS-Airmet/WA-Convective SIGMET/WST)

1. GENERAL

Flight advisories are issued by the AWC in Kansas City, Missouri, the AAWU in Anchorage, Alaska, and the WFO in Honolulu, Hawaii, for the occurrence or expected occurrence of specified en route weather phenomena which may affect the safety of aircraft operations. The report type designator WS for SIGMETs, WST for Convective SIGMETs, and WA for AIRMETs is used to effect selective distribution. Issuance times for WSs and WSTs are specified in National Weather Service (NWS) Instruction 10-811. WAs are issued as described in TBL 8-7-1.

1. DISTRIBUTION

WSs are distributed at unscheduled times to all Service A circuits. WAs and WSTs bulletins are distributed as scheduled products. Updates or amendments issued will completely replace the previously issued advisory.