Xm Wx Satellite Weather Products - Garmin G300 for Cessna SkyCatcher Pilot's Manual

XM WX SATELLITE WEATHER PRODUCTS

NEXRAD
NEXRAD (NEXt-generation RADar), is a network of 158 high-resolution Doppler
radar systems that are operated by the National Weather Service (NWS). NEXRAD
data provides centralized meteorological information for the continental United
States and selected overseas locations. The maximum range of a single NEXRAD
radar site is 250 nm. In addition to a wide array of services, the NEXRAD network
provides important information about severe weather and air traffic safety.
NEXRAD data is not real-time. The lapsed time between collection, processing,
and dissemination of NEXRAD images can be significant and may not reflect
the current radar synopsis. Due to the inherent delays and the relative age of
the data, it should be used for long-range planning purposes only. Never use
NEXRAD data or any radar data to penetrate hazardous weather. Rather, use it in
an early-warning capacity of pre-departure and enroute evaluation.
Composite data from all the NEXRAD radar sites in the United States is shown.
This data is composed of the maximum reflectivity from the individual radar
sweeps. The display of the information is color-coded to indicate the weather
severity level.
The display of radar coverage is always active when NEXRAD is selected. Areas
where NEXRAD radar coverage is not currently available or is not being collected
are indicated in grayish-purple (Weather (WX) Page Only). Radar capability exists
in these areas, but it is not active or is off-line.
neXRAD A
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
190-00921-00 Rev. E
bnoRmAlitieS
Garmin G300 Pilot's Guide
Hazard Avoidance
139