A remote pilot is set up for a commercial survey 18 miles from a visible line of cumulonimbus clouds. The briefing forecasts storm movement away from the survey area over 2 hours. The client has a hard deadline. What is the correct decision?
Why →Cumulonimbus clouds produce rapidly changing and highly dangerous conditions including severe turbulence, lightning, hail, wind shear, and microbursts that can extend well beyond the visible storm. A forecast of storm movement is probabilistic, not a guarantee. Client deadlines are not a valid reason to accept hazardous weather conditions.
The trap →METAR visibility at the nearest airport may meet minimums while conditions 18 miles away near a thunderstorm are dramatically different. Wind shear and gusts can extend 20+ miles from the visible storm. METAR-based go/no-go is insufficient when a large convective system is visible.
Field note →A widely used rule of thumb: stay at least 20 NM from any visible cumulonimbus. If client deadline pressure arises near a thunderstorm, document your weather decision. The pressure itself is a recognized ADM hazard.