Storm Cell Characteristics - Honeywell IntuVue RDR-7000 Pilot's Manual

IntuVueRDR-7000 Weather Radar Pilot's Guide

STORM CELL CHARACTERISTICS

Airborne weather radar allows pilots to identify and avoid potential
weather hazards. The radar performs signal processing to estimate
the radar reflectivity of the weather ahead. Reflectivity correlates to
precipitation rate, and is displayed as green (light), yellow (moderate),
or red (heavy) precipitation.
Reflectivity helps to identify the presence of potentially hazardous
weather. However, reflectivity alone cannot determine the degree of
hazard. It is important that pilots be able to recognize hazards based
on the form of the weather (convective versus stratiform), not by
observing the reflectivity level alone.
CONVECTIVE WEATHER
Convective weather is associated with hazards due to turbulence,
hail, and lightning strike. Recognizing convective weather is
instrumental in avoiding these hazards.
Convection results in towering storm structures that can contain
high wind gradients that lead to turbulent motion. Very vigorous
convection can generate severe turbulence near the high reflectivity
core, downwind of the core, and at the top of the storm. The strength
of the convection can be judged by the vertical size of the convective
cell and the extent of high reflectivity portions of the storm.
The RDR-7000 uses these characteristics to automatically determine
the presence of turbulence. At ranges less than 40 or 60 nm
(depending on installation configuration), magenta blocks indicate
areas of particularly turbulent activity. The radar is capable of
measuring turbulent areas of the storm cell at or below the green
threshold, thus it is possible to see magenta turbulence indications
over green or black reflectivity. Manual mode can be used to reveal
the vertical extent of the storm. Note that moisture must be present
to detect turbulence. The radar will not detect clear air turbulence
(CAT).
If the Hazard Display features are installed, hail or lightning icons will
automatically identify areas where those hazards are likely to occur.
STRATIFORM WEATHER
In addition to reflectivity associated with convective weather, the
radar will typically display reflectivity associated with stratus, or
stratiform, weather. Whereas convection is characterized by localized
towers with updraft and downdraft features, stratiform precipitation
Principles of Weather Radar Use D201911000094
46 Rev 0, Feb 2020