Stormscope WX-500, Interpretation, Cirrus Perspective by Garmin

How do you interpret the Stormscope WX-500 sensor output? Based on the User Guide for the Series II Model WX-500 here are a few of the basic items to understand:

Know the difference between Cell Mode and Strike Mode

Cell data is useful during periods of heavy electrical discharge activity. A pilot using cell mode during these periods will quickly see storm cells without having to analyze a screen full of discharge points. In cell data mode the WX-500 uses a clustering algorithm to locate storm cell activity.

Strike data is most useful during periods of light electrical activity because strike data may show initial discharge points of a building thunderstorm sooner than cell data mode. Strike data is mapped in relation to where the actual discharge is detected instead of plotting them close to an associated group of discharge points as in the cell mode.

Understand Strike Rate information

“Pilots may use the strike rate (approximate number of strikes per minute) to determine if storm cells are building or decaying  The MFD calculates the strike rate for the current range and view.”

Understand Radial Spread

In the strike display mode, it is common for a triangular-shaped stream of discharge points to appear between the aircraft symbol and a cluster of discharge points.  Algorithms used in the cell display mode greatly reduce radial spread and improve the depiction of thunderstorms on the display.

What are Randomly Scattered Discharge Points?

Atmospheric instability associated with cumulus clouds, or developing or dissipating thunderstorms could cause randomly scattered discharge points.  These are more likely to appear in the strike display mode than in cell mode because the cell mode uses a clustering algorithum.

What is Cluster & Splattering?

Refer to user guide, page 4-10.  A moderately active thunderstorm is depicted as a cluster of discharge points with splattering due to electrical discharges within 3-5 miles of the aircraft.  This indicates the aircraft is too close to the thunderstorm.  Aircraft should move away from the main cluster and avoid any groups of discharge points within 25 nmi range.

Understand the purpose for clearing output data from MFD screen

Clearing the discharge points periodically while monitoring thunderstorms is a good way to determine if the storm is building or dissipating.

“Caution: There are several atmospheric phenomena other than nearby thunderstorms which can cause isolated discharge points in the strike display mode. Clusters of two or more discharge points in the strike display mode however do indicate thunderstorm activity when they reappear after clearing the screen. Avoid the clusters and you’ll avoid the thunderstorms. In the cell display mode, even a single discharge point may represent thunderstorm activity and should be avoided.”

“Warning: Never use your Stormscope system to attempt to penetrate a thunderstorm. The FAA Advisory Circular, Subject: Thunderstorms, and the Airman’s Information Manual (AIM) recommend that you “avoid by at least 20 miles any thunderstorm identified as severe or giving an intense radar echo.”

Download WX-500 UserGuide wx500_pg

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