Garmin Aera 660 Pilot's Manual page 107

Radar Abnormalities
There are possible abnormalities regarding displayed NEXRAD images. Some, but
not all, of those include:
scans
Radar Limitations
Certain limitations exist regarding the NEXRAD radar displays. Some, but not all, are
listed for the user's awareness:
or precipitation characteristics (hail vs. rain). For example, it is not possible to
distinguish between wet snow, wet hail, and rain.
individual NEXRAD site cannot depict high altitude storms at close ranges, and
has no information about storms directly over the site.
reflectivity angles of the NEXRAD weather radar. (CONUS area only)
Radar Intensity
Colors are used to identify the different NEXRAD echo intensities (reflectivity)
measured in dBZ (decibels of Z). "Reflectivity" (designated by the letter Z) is the
amount of transmitted power returned to the radar receiver. The dBZ values increase
as returned signal strength increases. Precipitation intensity is displayed using colors
corresponding to the dBZ values.
190-02017-20 Rev. E
Hazard Avoidance
Garmin aera 660 Pilot's Guide
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