Garmin GTN 650 Pilot's Guide - Page 208

11.1.5.2 NEXRAD Limitations Foreword NEXRAD radar images may have certain limitations: Getting Started • NEXRAD base reflectivity does not provide sufficient information to determine cloud layers or precipitation characteristics. For example, it is Xpdr Ctrl not possible to distinguish between wet snow, wet hail, and rain. Com/Nav FPL Direct-To Proc Wpt Info Map • 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. • Each square block on the display represents an area of four square kilometers (2.15 NM). The intensity level reflected by each square represents the highest level of NEXRAD data sampled within the area. Block Area Is 4 km2 (2.15 NM2) Block Area Is 4 km2 (2.15 NM2) Traffic Terrain Weather Nearest Music Utilities System Messages Figure 11-9 NEXRAD Data Blocks 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 Symbols Appendix Index 11-10 Garmin GTN 625/635/650 Pilot's Guide 190-01004-03 Rev. B