Hail is a good reflector of energy and will return very high dBZ values. Since hail can cause the rainfall estimates to be higher than what is actually occurring, steps are taken to prevent these high dBZ values from being converted to rainfall. This can be seen in the images below from the Salt Lake City radar. It is most readily seen around the name 'Wendover'. Base reflectivity only shows reflected energy at a single elevation scan of the radar.
Composite reflectivity displays the highest reflectivity of ALL elevations scans.
This occurs often with severe thunderstorms. The updraft, which feeds the thunderstorm with moist air, is strong enough to keep a large amount of water aloft. Once the updraft can no longer support the weight of suspended water then the rain intensity at the surface increases as the rain falls from the cloud. The table below shows the standard difference from UTC time to local time. It refers to time on the zero or Greenwich meridian, which is not adjusted to reflect either changes either to or from Daylight Saving Time.