BendixKing IN-182A System RDR-2000 - Manual (Page 27)

Effective Date: 5/98 RDR 2000 Pilot's Guide: Rev 3
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Weather Mapping and Interpretation
These echoes appear quite suddenly and along any edge of the storm
outline. They also change in intensity and shape in a matter of seconds,
and for this reason careful monitoring of the display is essential. It must
be noted that weak or fuzzy projections are not normally associated with
hail; however, such echoes should be watched closely for signs of rapid
intensification.
The 40 nm operating range, with occasional up-tilt to check for fresh hail
from above, will generally yield good results.
Note: It takes an experienced eye to identify “hooks” and “fingers” and
other radar echo characteristics which can indicate hail or tornadoes.
However, the pilot can be sure that any echo with very ragged edges or
rapid changes in shape or intensity will contain severe turbulence.
ICING
There is reason to believe that radar will be of assistance in locating
areas of heavy icing conditions. However, weather radar has not yet
proved its ability to distinguish between super-cooled water droplets and
ice crystals, since both are usually quite small. Needless to say, the
operational problem in each case would be different. In the first case an
icing condition would definitely exist but in the second case the pure
crystals would offer no danger.
It should be remembered, however, that super-cooled water and ice
crystals can co-exist. In each case the radar echo would be small or
even non-existent due to the minute size of the free water particles. At
this time, it appears that radar is not going to give warning for cloud icing
unless it happens to be involved with active precipitation at the time.
When precipitation is occurring, however, the areas of maximum ice
exposure should appear as sandy or grainy echoes.
An icing condition that radar might possibly detect is the intermittent
moderate or heavy icing condition associated with unstable air lifted by
frontal action or orographic effects. In this situation the cumulus cells are
hidden by surrounding cloud layers but could be spotted by radar. This
would be of assistance in avoiding the moderate to heavy icing which
occasionally occurs in cumulus clouds.
Note: Thunderstorm icing can be extremely hazardous.
SNOW
Dry snowfall has not been detected with any success on weather radar.
However, a characteristic sandy or grainy echo identifies the presence of
steady moderate to heavy wet snow. Such echoes are not readily
obvious and require study of the display before they can be seen.