QICP Login    Registration info
Skip Navigation Links weather.gov 
NOAA logo-Select to go to the NOAA homepage
NOAA's National Weather Service
  Select to go to the NWS homepage
Aviation Digital Data Service (ADDS)
     

 


USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

ADDS Home PageTurbulenceIcingConvectionWinds/TempsProg ChartsJava Tools Airmets site description
METARsC&VTAFsPIREPsAIRMETsSatelliteRadar

ADDS - AIRMETs Help Page (3 of 4)
Back to AIRMETs Page or AIRMETs help page 4
A SIGMET (SIGnificant METeorological Information) advises of weather potentially hazardous to all aircraft other than convective activity.
 
   SIGMETs are issued (for the lower 48 states and adjacent coastal waters) for the following weather-impacted reasons:
  • Severe Icing
  • Severe or Extreme Turbulence
  • Duststorms and sandstorms lowering visibilities to less than three (3) miles
  • Volcanic Ash
   These SIGMET items are considered to be widespread because they must be affecting or be forecast to affect an area of at least 3000 square miles at any one time. However, if the total area to be affected during the forecast period is very large, it could be that only a small portion of this total area would be affected at any one time.    SIGMETs are issued for 6 hour periods for conditions associated with hurricanes and 4 hours for all other events. If conditions persist beyond the forecast period, the SIGMET is updated and reissued. Convective SIGMETS are issued hourly for thunderstorm-related aviation hazards.

Turbulence     Icing     Convection     Winds/Temps     Progs     Java Tools
METARs     TAFs     PIREPs     SIGMET/AIRMET     Satellite     Radar
Page loaded:   03:03 UTC
20:03 PM Pacific   |   21:03 PM Mountain   |   22:03 PM Central   |   23:03 PM Eastern   |   WOC34

NOAA's National Weather Service
National Centers for Environmental Prediction
Aviation Weather Center
7220 NW 101st Terr., Room 118
Kansas City, MO 64153-2371
Contact AWC Internet Services
Page last modified: February 26, 2013
Disclaimer

Credits

Glossary
Privacy Policy

About Us

Career Opportunities

This Qualified Internet Communication Provider's (QICP) servers and communication interfaces are approved by the FAA as secure, reliable, and accessible in accordance with AC 00-62.
    1) This QICP does not ensure the quality and currency of the information transmitted to you.
    2) The user assumes the entire risk related to the information and its use.