Owner's Manual
Table Of Contents
- GXM 30 Owner's Manual
- Introduction
- Getting Started
- XM WX Weather Features
- Displaying Weather Information
- NEXRAD Radar
- Satellite Mosaic
- Lightning
- Storm Cells
- Hurricanes
- Surface Winds
- Winds Aloft
- Surface Pressure
- Fronts
- Visibility
- County Warnings
- Water Temperature
- Wave Period
- Wave Direction
- Wave Height
- Marine Warnings
- Buoy Reports
- METAR
- AIRMET
- SIGMET
- TFR
- Echo Tops
- Freezing Level
- Forecast
- TAF
- XM Radio
- Appendix

23 GXM 30 XM Radio Smart Antenna Owner’s Manual
SIGMET
A SIGMET (SIGnificant METeorlogical Forecast) advises
of weather that is potentially hazardous to all aircraft. In the
contiguous United States, items covered are: severe icing,
severe or extreme turbulence, volcanic ash, dust storms, and
sandstorms that lower visibility to less than three statute miles.
A Convective SIGMET is issued for: thunderstorms, isolated
severe thunderstorms, embedded thunderstorms, hail at the
surface, and tornadoes. A SIGMET is widespread. A SIGMET
must affect or be forecast to affect an area of at least 3,000
square miles.
SIGMETs are displayed as a yellow dashed line. To view
SIGMET data, select the SIGMET using the map pointer. To
view detailed information, press ENTER.
SIGMET detailed information
SIGMET selected with map pointer
XM WEATHER FEATURES > SIGMET










