Advisories

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):
   • Inside the CONUS:
     • Nonconvective.
     • Convective.
   • Outside the CONUS.
2. Airmen’s Meteorological Information (AIRMET):
   • Inside the CONUS.
   • 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).

1. 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.

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 30º N latitude and the portion east of 140º W longitude, which is between the Equator and 30º 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 30º N latitude and between 140º W and 130º E longitude (see Figure 26-3).