Fis-B Nexrad - Garmin GPS 175 Pilot's Manual

5.4.3

FIS-B NEXRAD

WARNING
NEVER USE NEXRAD WEATHER FOR MANEUVERING IN, NEAR, OR
AROUND AREAS OF HAZARDOUS WEATHER. NEXRAD IMAGES ARE
SNAPSHOTS OF PAST WEATHER DATA. THEY ARE NOT SAFE FOR USE
AS REAL TIME DEPICTIONS OF NEARBY WEATHER ACTIVITY.
CONUS NEXRAD
NEXRAD weather radar displays a mosaic of precipitation data, colored according to
reflectivity. Composite reflectivity images depict the highest radar energy received
from multiple antenna tilt angles at various altitudes. Base reflectivity images depict
radar returns from the lowest antenna tilt angle.
The precipitation intensity level reflected by each pixel represents the highest level of
composite radar reflectivity data sampled in that location.
A clear understanding of ground-based Doppler weather radar capabilities will
allow you to interpret the NEXRAD weather imagery in the safest way possible.
The National Oceanic and Atmospheric Administration hosts a description of the
technology on its website:
RADAR DATA ANIMATIONS
To depict trending weather movements over time, an animation
function stitches the last three to six received radar images together
in sequence, from oldest to newest, and replays them on a
continuous loop.
Play and stop controls are active when three or more NEXRAD images
are available for playback.
190-02207-02 Rev. 1 GPS 175/GNX 375 Pilot's Guide
https://www.weather.gov/jetstream/doppler_intro
Hazard Awareness
Regional NEXRAD
5-11