What weather phenomenon is denoted by the abbreviation GR?

The abbreviation GR is associated with hail. In aviation and meteorological terms, GR specifically refers to this type of precipitation, which consists of balls or irregular lumps of ice. Hail forms during thunderstorms when intense turbulence within the storm causes water droplets to be lifted to great heights where they freeze before falling to the ground.

Understanding meteorological abbreviations like GR is critical for pilots and drone operators, as hail can pose significant hazards, including damage to aircraft and visibility issues. Recognizing such weather phenomena allows for better planning and response to changing weather conditions during flight operations.