Section 2: Nexrad Overview; Nexrad Description; Nexrad Abnormalities; Nexrad Limitations - Garmin 400 Series Pilot's Manual Addendum

Section 2
NEXRAD Overview
CAUTION: NEXRAD weather data is to be used
for long-range planning purposes only. Due to
inherent delays and relative age of the data that
can be experienced, NEXRAD weather data cannot
be used for short-range avoidance of weather.
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Section 2: NEXRAD Overview

NEXRAD Description

WSR-88D weather surveillance radar or NEXRAD (NEXt generation 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, etc).
• 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.
• Depending on the amount and complexity of the weather data being received, the resolution of the
displayed NEXRAD data may be as high as 2 km (depending on available system memory).