Nexrad Abnormalities - Garmin GTN 625 Pilot's Manual

11.4.2
Foreword
WSR-88D weather surveillance radar or NEXRAD (NEXt generation RADar) is
Getting
a Doppler radar system that has greatly improved the detection of meteorological
Started
events such as thunderstorms, tornadoes, and hurricanes. An extensive network
Xpdr Ctrl of NEXRAD stations provides almost complete radar coverage of the continental
United States, Alaska, and Hawaii. The unobstructed range of each NEXRAD is
Com/Nav
124 nautical miles.
11.4.2.1
FPL
There are possible abnormalities regarding displayed NEXRAD images. Some,
Direct-To
but not all, causes of abnormal displayed information include:
• Ground Clutter
Proc
• Strobes and spurious radar data
Wpt Info
• Sun strobes, when the radar antenna points directly at the sun
Map
• Military aircraft deploy metallic dust which can cause alterations in radar
scans
Traffic
• Interference from buildings or mountains, which may cause shadows
• Scheduled maintenance may put a radar off-line
Terrain
11.4.2.2
Weather
Certain limitations exist regarding the NEXRAD radar displays. Some, but
not all, are listed for the user' s awareness:
Nearest
• The Regional NEXRAD "pixels" are 1.5 minutes (1.5 nautical miles
Services/
Music
= 2.78 km) wide by 1 minute (1 nautical miles = 1.852 km) tall. The
CONUS NEXRAD "pixels" are 7.5 minutes (7.5 nautical miles = 13.89
Utilities
km) wide by 5 minutes (5 nautical miles = 9.26 km) wide. Above 60
degrees of latitude the Regional NEXRAD "pixels" are 3 minutes/nautical
System
miles. CONUS NEXRAD is not available above 60 degrees of latitude.
The intensity level reflected by the pixel will be the highest level sampled
Messages
within the area covered by each pixel.
Symbols
Appendix
Index
11-52
FIS-B NEXRAD

NEXRAD Abnormalities

NEXRAD Limitations
Garmin GTN 625/635/650 Pilot's Guide 190-01004-03 Rev. F