Radial Spread; Typical Patterns; Three Clusters Within The 200Nm Range Ring - Honeywell KMD-150 Pilot's Manual

Stormscope Operation
The WX-500 detects electrical discharges and sends them to the KMD
150 as storm cells or as independent strikes. The following examples
include the KMD 150's Stormscope screens in both the cell display mode
and the strike display mode. When in map mode, if enabled, the cells
and strikes will be displayed as lightning icons. To make a more detailed
analysis of the storm, switch back to the dedicated Stormscope screen.

RADIAL SPREAD

When the KMD 150 is in the strike display mode, it is common for a trian-
gular-shaped stream of discharge points to appear between the aircraft
symbol on the Stormscope screen and a cluster of discharge points
within the range of the WX-500. A similar stream of discharge points
may appear radiating away from the aircraft symbol in the direction of
possible thunderstorm activity beyond the range of the WX-500. These
phenomena are examples of radial spread. Discharge points in radial
spread do not necessarily indicate the exact location of atmospheric
electrical discharges. To counteract radial spread, BFGoodrich Avionics
Systems applied its extensive research in lightning detection to develop
enhanced lightning positioning algorithms. These algorithms (used only
in the cell display mode) greatly reduce radial spread and improve the
depiction of thunderstorms on the display. The strike display mode does
not use the enhanced lightning positioning algorithms; instead, it uses
technology similar to that found in older Stormscope systems and in
competitor lightning detection systems.

TYPICAL PATTERNS

Three Clusters within the 200 nm Range Ring
Figure 13-5 shows the Stormscope screen in the 360° weather view at
the 200 nm range. Using this knowledge, the outer range ring, and the
azimuth markers, the three clusters of discharge points on the left-hand
Stormscope screen (cell display mode) can be interpreted as repre-
senting three thunderstorm cells at the following azimuth and range:
Cluster
1
2
3
Analysis of the right-hand Stormscope screen (strike display mode)
yields a similar, but less certain interpretation due to radial spread.
Rev 1 Mar/2000
Azimuth (clock position) Range
11:00
4:00
4:00
180 nm
75 nm
180 nm
116
KMD 150 Pilot's Guide