Which remark notation indicates the occurrence of thunderstorms in the vicinity?

The choice identified indicates the presence of thunderstorms with the abbreviation "TS," which is a standard meteorological term used in aviation weather observations. When pilots and flight planners see "TS" in a weather report, it signals that thunderstorms are either occurring or are expected to occur in the area surrounding the reporting station.

Recognizing thunderstorms is crucial for flight safety due to the severe weather conditions they can bring, such as turbulence, lightning, and heavy precipitation. The use of "TS" is straightforward and universally understood within the context of aviation meteorology, allowing for effective and swift communication of significant weather phenomena.

In contrast, the other options represent different weather phenomena or conditions. For instance, "OCNL LTG" refers to occasional lightning without specifically mentioning thunderstorms. "LTGICCG" indicates lightning in the vicinity of cumulonimbus clouds, which could suggest thunderstorms, but it does not directly state their occurrence. Lastly, "VC TSB" indicates thunderstorms in the vicinity, but not at the station itself, differentiating it from the clear and direct indication provided by "TS." This highlights the importance of precise terminology in aviation weather communications to ensure clarity regarding current weather conditions.