ADDS - Aviation Digital Data Service


ADDS - AIRMETs Help Page (4 of 4)
Back to AIRMETs Page
CONVECTIVE SIGMETs are issued in the conterminous U.S. for:
  • Severe surface weather including:
    • surface winds greater than or equal to 50 knots
    • hail at the surface greater than or equal to 3/4 inches in diameter
    • tornadoes
  • Embedded thunderstorms
  • Line of thunderstorms
  • Thunderstorms greater than or equal to VIP level 4 affecting 40% or more of an area at least 3000 square miles
   Any Convective SIGMET implies severe or greater turbulence, severe icing, and low level wind shear. A Convective SIGMET may be issued for any convective situation which the forecaster feels is hazardous to all categories of aircraft. Bulletins are issued hourly at Hour+55. The text of the bulletin consists of either an observation and a forecast or just a forecast. The forecast is valid for up to 2 hours.

Page loaded:  16:05 UTC  |   08:05 AM Pacific  |   09:05 AM Mountain  |   10:05 AM Central  |   11:05 AM Eastern

 

ADVISORIES

FORECASTS

FORECASTS

OBSERVATIONS

USER TOOLS

ABOUT US