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Aviation Weather Handbook

FAA-H-8083-28B Version 2026
All Library Documents FAA Source

Chapter 26

Advisories

26.1 Introduction

The third of five types of aviation weather information contained in this handbook are advisories. For this handbook, advisories include the following:

  1. Significant Meteorological Information (SIGMET):
    1. Inside the CONUS:
    2. Non-Convective.
    3. Convective.
    4. Outside the CONUS.
  2. Airmen’s Meteorological Information (AIRMET):
    1. Inside the CONUS.
    2. Outside the CONUS.
  3. Center Weather Advisory (CWA).
  4. Volcanic Ash Advisory (VAA).
  5. Tropical Cyclone Advisory (TCA).
  6. Space Weather Advisory.
  7. Wind Shear Alerts.
  8. Airport Weather Warning (AWW).

26.2 Significant Meteorological Information (SIGMET)

A SIGMET is a concise description of the occurrence or expected occurrence of specified en route weather phenomena that may affect the safety of aircraft operations. SIGMETs are issued in text format and intended for dissemination to all pilots in flight to enhance safety. SIGMETs are issued as soon as practical to give notice to operators and aircrews of potentially hazardous en route conditions.

Although the areas where the SIGMETs apply may be shown graphically, a graphical depiction of the SIGMET area is not the entire SIGMET. Additional information regarding the SIGMET may be contained in the text version.

26.2.1 SIGMET Issuance

SIGMETs are issued from MWOs. The United States has three MWOs: the AWC, the AAWU, and the WFO Honolulu.

The AWC is responsible for:

  • Twenty domestic ARTCC FIRs covering the CONUS and adjacent coastal waters. CONUS SIGMETs, except for Convective SIGMETs, are grouped into six areas (see Figure 26-1).
  • The New York, Houston, Miami, and San Juan Oceanic FIRs (see Figure 26-2).
  • The Oakland Oceanic FIR north of 30°N latitude and the portion east of 140° W longitude, which is between the Equator and 30°N latitude (see Figure 26-3).

The AAWU is responsible for the Anchorage Continental FIR and the Anchorage Oceanic FIR (see Figure 26-3).

WFO Honolulu is responsible for the Oakland Oceanic FIR south of 30°N latitude and between 140°W and 130°E longitude (see Figure 26-3).

Figure 26-1. AWC SIGMET Areas of Responsibility—CONUS
Figure 26-1. AWC SIGMET Areas of Responsibility—CONUS
Figure 26-2. AWC SIGMET Areas of Responsibility—Atlantic Basin
Figure 26-2. AWC SIGMET Areas of Responsibility—Atlantic Basin
Figure 26-3. SIGMET Areas of Responsibility—Pacific Basin
Figure 26-3. SIGMET Areas of Responsibility—Pacific Basin

Note that KKCI refers to the AWC that is in Kansas City, MO.

26.2.2 SIGMET Identification

U.S. SIGMETs (other than Convective SIGMETs) are assigned a series identifier:

  • AWC for the CONUS:
    • NOVEMBER, OSCAR, PAPA, QUEBEC, ROMEO, UNIFORM, VICTOR, WHISKEY, XRAY, and YANKEE. Note that SIERRA and TANGO are excluded.
  • AWC for the Oakland Oceanic FIR:
    • ALFA, BRAVO, CHARLIE, DELTA, ECHO, FOXTROT, GOLF, and HOTEL.
  • Honolulu MWO for the Oakland Oceanic FIR:
    • NOVEMBER, OSCAR, PAPA, QUEBEC, ROMEO, SIERRA, TANGO, UNIFORM, VICTOR, WHISKEY, XRAY, YANKEE, and ZULU.
  • AAWU for the Anchorage FIR:
    • INDIA, JULIET, KILO, LIMA, and MIKE.

A number is assigned sequentially with each issuance until the phenomenon ends. At 0000 UTC each day, all continuing SIGMETs are renumbered to one, regardless of a continuation of the phenomena (e.g., YANKEE 1, YANKEE 2, YANKEE 3).