 An overshooting top forms when a thunderstorm's updraft, due to momentum from rapid ascent and strength of lifting through the free convective layer (FCL), protrudes its equilibrium level, forming a dome-like structure above the anvil.This can occur with any cumulonimbus cloud when instability is high.Whereas anvils form at the equilibrium level, overshooting tops continue to the maximum parcel level (MPL).