Garmin G1000 Reference Manual page 143

CELL MOV – pressing the CELL MOV softkey shows
the storm cells identified by the ground-based
system. The movement is depicted by an arrow.
The update rate is every 12 minutes.
SIG/AIR – pressing the SIG/AIR softkey shows
SIGMET and AIRMET information to advise the
pilot of potentially hazardous weather. The advisory
covers an area of at least 3,000 square miles at any
one time. The update rate is every 12 minutes.
NOTE: SIGMETs are broadcasted for hazardous
weather that is considered of extreme importance
to all aircraft. SIGMETs (acronym for "SIGnificant
METeorological information") warn of the fol-
lowing weather hazards: severe icing, severe and
extreme turbulence, dust storms, sandstorms, or
volcanic ash lowering visibility to less than 3
miles. A Convective SIGMET (WST) is issued for
hazardous convective weather (such as torna-
does, thunderstorms, hail) and covers severe or
great turbulence, severe icing, and low-level wind
shear. A localized SIGMET is a significant weather
condition occurring at a localized geographical
position.
Garmin G1000 Cockpit Reference Guide for Cessna Nav III
SECTION 6 – MFD
OPTIONAL INTERFACES
NOTE: AIRMETs are broadcasted for weather
phenomena that potentially affects all aircraft.
For pilots of light aircraft, AIRMET (acronym for
"AIRman's METeorological information) gives
valuable information about the following con-
ditions: moderate icing, moderate turbulence,
sustained winds 30 knots or greater at the sur-
face, widespread area with a ceiling of less than
1,000 feet and/or visibility less than 3 miles and
extensive obscurement of mountains. These are
important to light aircraft, as they have limited
flight capabilities due to lack of equipment and/or
instrumentation.
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