Pilot's Guide

190-00663-03 Rev. A
Garmin G1000 Pilot’s Guide for the Beechcraft C90A/GT/GTi
319
HAZARD AVOIDANCE
neXRAD liMitAtionS
NEXRAD radar images may have certain limitations:
• NEXRAD base reflectivity does not provide sufficient information to determine cloud layers or precipitation
characteristics (wet hail vs. rain). For example, it is not possible to distinguish between wet snow, wet
hail, and rain.
• NEXRAD base reflectivity is sampled at the minimum antenna elevation angle. An individual NEXRAD
site cannot depict high altitude storms at close ranges. It has no information about storms directly over
the site.
• When zoomed in to a range of 30 nm, each square block on the display represents an area of four square
kilometers. The intensity level reflected by each square represents the highest level of NEXRAD data
sampled within the area (Figure 6-12).
• If the precipitation type is unknown, the system displays the precipitation as rain, regardless of actual
precipitation type.
Figure 6-12 NEXRAD Data - Zoomed
Block represents
4 km
2
The following may cause abnormalities in displayed NEXRAD radar images:
• Ground clutter
• Strobes and spurious radar data
• Sun strobes (when the radar antenna points directly at the sun)
• Interference from buildings or mountains, which may cause shadows
• Metallic dust from military aircraft, which can cause alterations in radar scans