Nexrad overview, Nexrad description, Nexrad abnormalities – XM Satellite Radio GXM30 User Manual

Page 37: Nexrad limitations

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GXM 30 XM Radio Smart Antenna Owner’s Manual


NEXRAD Overview

NEXRAD Description

NEXRAD Radar is a Doppler radar system that has greatly

improved the detection of meteorological events such as

thunderstorms, tornadoes, and hurricanes. An extensive

network of NEXRAD stations provides almost complete radar

coverage of the continental United States, Alaska, and Hawaii.

The range of each NEXRAD is 124 nautical miles.

NEXRAD Abnormalities

There are possible abnormalities regarding displayed NEXRAD

images. Some, but not all, of those include:

• Ground clutter
• Strobes and spurious radar data
• Sun strobes, when the radar antenna points directly at

the sun

• Military aircraft deploy metallic dust (chaff) which can

cause alterations in radar scans

• Interference from buildings or mountains, which may

cause shadows

NEXRAD Limitations

Certain limitations exist regarding the NEXRAD radar

displays. Some, but not all, are listed for the user’s awareness:

• NEXRAD base reflectivity does not provide sufficient

information to determine cloud layers or precipitation

characteristics (hail vs. rain).

• NEXRAD base reflectivity is sampled at the minimum

antenna elevation angle. An individual NEXRAD site

cannot depict high altitude storms at close ranges, and

has no information about storms directly over the site.