What is the best way to encode a thunderstorm that began at 1515z and ended at 1534z in an observation?

The correct encoding of a thunderstorm in an observation requires specifying the time the thunderstorm began and, importantly, the end time. The format typically used includes the thunderstorm type designation (TS) followed by the beginning time (B) in hours and minutes (15 for 1515z) and the ending time (E) also in hours and minutes (34 for 1534z).

In this case, "TSB15E34" accurately reflects that the thunderstorm began at 1515z and ended at 1534z by incorporating the respective beginning and ending times. This ensures that anyone reading the observation can clearly understand both the start and end time of the event, which is crucial for assessing weather impacts.

Other combinations do not provide the accurate end time of the thunderstorm or misrepresent the format required for clarity and standardization in aviation weather reporting, thereby making them less suitable for accurate communication of the event.