Read radar product context, inspect empirical rainfall and beam geometry, and retain the limits of a two-frame motion projection.
Record whether the image is base reflectivity, a composite, velocity or a derived product. Keep radar location, elevation angle, range, scan timestamp and any product age visible. A color legend belongs to its product; do not read a composite value as a direct surface measurement.
Inspect surrounding frames and available quality information for blockage, clutter, anomalous propagation, attenuation and melting-layer effects. Reflectivity depends on hydrometeor properties and sampling geometry. A high dBZ value alone does not determine hail size, rainfall intensity at the ground or storm severity.
For a liquid-rain learning case, choose the actual Z–R coefficients and their unit basis. Convert dBZ to linear Z before applying the relation. Compare alternate documented relations when appropriate and keep them as separate cases. Do not assume one historical relation applies to snow, hail or every rainfall regime.
Use slant range, antenna altitude, elevation angle and full beam width. State whether the effective-Earth multiplier is the standard 4/3 approximation or a documented custom value. Review center and edge rays relative to the altitude datum; terrain blockage and variable atmospheric refraction require further data.
For a retrospective or educational case, identify the same feature at two scan times in a common local east/north coordinate system. Inspect the speed, motion-to bearing and future closest approach. A missed target circle or already-inside result is meaningful; do not force a positive arrival time.
Compare radar estimates with quality-controlled gauges over matching intervals and with current official products. Accumulated rain requires a time series, not a single reflectivity frame. Keep the original product, coefficients, beam geometry and motion assumptions with the saved case so later changes can be explained.
Calculate liquid-rain rate using entered Z–R coefficients, with the model limitations preserved. · Calculate idealized center and edge beam heights without treating them as observed cloud tops. · Project constant-motion entry and closest approach while retaining stationary, receding and path-miss cases.
Integrate actual interval-mean rates with explicit coverage instead of multiplying one scan by an arbitrary duration.
Retain independent gauge and surface observations with timestamps.
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NWS research discusses differing Z–R relations and why a single reflectivity conversion is not universally applicable.
wradlib documents effective-Earth radar-bin altitude using slant range, elevation and antenna altitude.
Use current warnings and shelter guidance; a modeled arrival time is not a reason to remain exposed.
The time shown in a screenshot may be a scan time, processing time or application refresh time; identify which one is being used.
A calculated beam-edge altitude does not establish that terrain is clear or that a target will be detected.