ForeFlight Question of the Month:
If the Four-Color Radar option had been turned on for the ADS-B NEXRAD on the iPad for this flight, the image would have appeared:
A. Far more ominous.
B. Far more benign.
C. About the same.
D. Exactly the same, because the Four-Color Radar option only applies to internet weather.
Answer: A. Four-Color Radar simplifies the color-to-dBz relationship. Returns below 20 dBz have no color, 20-30 dBz is green, 30-40 dBz is yellow, 40-50 dBz is red, and >50 dBz is magenta. This shifts what are gradations of green to a combination of green and yellow. (The image below is just an approximation of what the iPad might have shown with Four-Color Radar during this flight.)
Using Four-Color Radar, yellow better corresponds to a caution area and red, a no-fly. As previously stated, color isn’t the only factor to consider. NEXRAD mosaics shouldn’t be used for sole-source choices on navigating any kind of weather, especially for close-in tactical decisions.