SHRT SHRTWV SHSN SHWR Sidelobe SIGMET signal-to-noise ratio Significant wave height Significant Weather Outlook SIGWX Single Cell Thunderstorm SITOR Sky Condition SKYWARN SL
| SLD Sleet Sleet Warning SLGT Slight Chance Slight Risk Sling Psychrometer SLO SLOSH SLP SLT SLY sm SMA Small Craft
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