METAR weather code reference for GS (Small Hail / Snow Pellets)
Small hail (graupel) or snow pellets less than 5 mm in diameter. These ice pellets form when supercooled water droplets freeze onto snowflakes. Less damaging than full hail but still indicates convective activity and potential for icing conditions.
Here are common ways GS appears in real METAR observations:
GS-GSTSGSThese METAR codes are commonly seen alongside GS or describe related weather phenomena:
Ice precipitation consisting of balls or irregular lumps of ice with a diameter of 5 mm (about 1/4 inch) or greater. Hail is associated with strong thunderstorms and poses a severe hazard to aircraft, capable of causing structural damage to airframes, windshields, and engines.
Small, translucent balls of ice that bounce when hitting the ground. Ice pellets (sleet) form when snowflakes melt in a warm layer aloft and then refreeze in a cold layer near the surface. Their presence indicates a complex temperature profile and often means freezing rain may be nearby.
A convective storm producing lightning and thunder. In METAR reports, TS indicates that thunder has been heard at the station within the observation period. Thunderstorms are among the most dangerous weather phenomena for aviation, bringing turbulence, wind shear, hail, heavy rain, and microbursts.