Nexrad Intensity - Garmin GNC 420(A) Pilot's Manual & Reference

SECTION 11
ADDITIONAL FEATURES

NEXRAD Intensity

Colors are used to identify the different NEXRAD echo intensities (reflectivity) measured in dBZ (decibels of Z).
Reflectivity (designated by the letter Z) is the amount of transmitted power returned to the radar receiver. The dBZ values
increase as returned signal strength increases. Precipitation intensity is displayed on the GNC 420 units using colors
represented by the dBZ values listed in Table 11-6.
Display dBZ
GDL 49 GDL 69
<-10
-10
-5
GREEN
10
GREEN
15
20
25
30
YELLOW YELLOW
35
40
45
RED RED
50
55
60
65
70
75
NOTe: The information presented in this Pilot's Guide regarding NeXraD is not meant to be comprehensive.
The NOaa website (www.noaa.gov) contains complete and detailed information regarding NeXraD weather
radar operation and theory.
11-20
Rain Snow
(inches/hour) (inches/hour)
.00 .00
.00 .00
.00 trace
0 .00 trace - .05
5 .00 trace - .10
0 – trace .10
.01 .1-.2
.02 .2-.3
.05 .3-.5
.09 .5-.7
.24 .7-1.0
.48 >1 or sleet
1.25 >1 or sleet
2.5 sleet
5.7 sleet
12.7
Table 11-6 NEXRAD Intensity Colors
GNC 420(A) Pilot's Guide and Reference
Source of NEXRAD Echo
Cloud
Atmos Rain
√
√ √
√ √
√ √
√ √
√ √ Light
Light
Light
Light
Light – Moderate
Moderate
Heavy
Heavy
Intense
Extreme
Extreme
Extreme
Snow Sleet Hail
Very Light
Light
Light
Light
Light
Light – Medium
Moderate
Heavy √
Heavy √
Heavy √
√ √
√ √
√
√
Large
Large
190-00140-20 Rev. K