What does the term "SH" signify before precipitation types in a METAR?

The term "SH" in a METAR signifies "showers" when it appears before precipitation types. This abbreviation indicates that the type of precipitation is occurring in the form of brief, intermittent bursts, rather than steady rainfall or snowfall. Showers are typically characterized by their variability in intensity and can occur sporadically.

In the context of METAR reports, understanding the distinction between showers and other forms of precipitation is essential for interpreting current weather conditions. For instance, if "SH" is reported, a pilot or meteorologist can anticipate that the precipitation may not be continuous but rather fluctuate, which could affect visibility and flight operations.

Each of the other options represents different weather conditions but does not describe the specific nature of "showers" as indicated by "SH." For example, while "Snow" simply refers to frozen precipitation, "Sky condition" pertains to the overall state of the sky, and "Heavy rain" indicates a certain intensity of rainfall without the specificity that the term "showers" conveys. Understanding these distinctions is crucial for accurate weather observation and reporting.