Radar
Hail Core Radar Explained: Why Bright Colors Can Mean Large Hail
How hail cores appear on radar, why very high reflectivity can signal hail, and why radar cannot tell exact hail size by color alone.
Quick answer: A hail core is an area of a thunderstorm where hail is likely, often shown by very high reflectivity on radar.
Reflectivity clue
Hail can return strong radar energy, creating bright colors or high dBZ values.
But heavy rain can also look intense, so color alone is not exact hail size.
Other data
Meteorologists use storm height, environment, dual-pol radar, reports, and warning criteria to judge hail risk.
Some apps simplify the signal more than professionals do.
Safety
Large hail can break glass, injure people, and damage vehicles and roofs.
Move indoors and away from windows during severe hail warnings.