It has been a hot topic for the past few years, that 3/4 inch diameter hail simply doesn't pose a damage threat. Simply put, the speed in which a hail stone that size falls to the ground, doesn't achieve a high enough speed to cause damage. However, a hail stone that is 1 inch in diameter will achieve a high enough speed to cause damage. So, the National Weather Service has bumped up the severe criteria for hail to 1 inch in diameter or larger. A good move, if you ask me. Trying to determine the difference between 3/4 inch and 1 inch diameter hail based on radar is pretty tough. It may cause a few less warnings to be issued, but we'll see. Below is a VODCAST that the NWS put together talking about why the change was made.
Discussing the reasoning behind the change, a 5-minute presentation by our Central Region Headquarters is available on this VODCAST.
Chief Meteorologist Brian Bledsoe