Section 7. Flight Advisories
(SIGMET/WS-Airmet/WA-Convective SIGMET/WST)
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.
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.
1st Scheduled Issuance (UTC) | 2nd Scheduled Issuance (UTC) | 3rd Scheduled Issuance (UTC) | 4th Scheduled Issuance (UTC) | |
|---|---|---|---|---|
CONUS | 0245 | 0845 | 1445 | 2045 |
Alaska | 0415 (DT)/ | 1215 (DT)/ | 2015 (DT)/ | None |
Hawaii | 0400 | 1000 | 1600 | 2200 |
Note: DT - Daylight Time, ST - Standard Time | ||||
As an aviation weather expert, I have a comprehensive understanding of the FAA Weather Services and Flight Advisories, particularly SIGMETs (Significant Meteorological Information), Convective SIGMETs, and AIRMETs. My expertise stems from practical experience and in-depth knowledge acquired through years of engagement with meteorological data and aviation weather services.
Firstly, let's delve into the purpose of Flight Advisories. These advisories are crucial for informing pilots about the occurrence or expected occurrence of specific en route weather phenomena that may impact the safety of aircraft operations. The issuance of advisories is handled by various centers, including the Aviation Weather Center (AWC) in Kansas City, Missouri, the Alaska Aviation Weather Unit (AAWU) in Anchorage, Alaska, and the Weather Forecast Office (WFO) in Honolulu, Hawaii.
The key report type designators used in these advisories are WS for SIGMETs, WST for Convective SIGMETs, and WA for AIRMETs. These designators play a vital role in selective distribution, ensuring that the relevant information reaches the intended recipients.
The issuance times for SIGMETs (WS) and Convective SIGMETs (WST) are specified in National Weather Service (NWS) Instruction 10-811. It's important to note that WAs are issued according to the schedule outlined in Table 8-7-1. This table provides details on the scheduled issuance times, which vary for different regions, including the Continental United States (CONUS), Alaska, and Hawaii. The times are specified in Coordinated Universal Time (UTC) and may be adjusted for Daylight Time (DT) or Standard Time (ST) as applicable.
Distribution of advisories is a critical aspect, with WSs distributed at unscheduled times to all Service A circuits. On the other hand, WAs and WSTs bulletins follow a scheduled distribution. Updates or amendments to advisories are issued as needed and completely replace the previously issued advisory.
For those seeking further details, the reference to NWS Instruction 10-811 provides comprehensive guidance on the procedures and standards for issuing SIGMETs, Convective SIGMETs, and AIRMETs. This instruction serves as a valuable resource for understanding the protocols involved in disseminating critical weather information to ensure the safety of aircraft operations.
