While it may look like hail falling from the sky today, it was not. Hail is only associated and formed within thunderstorms.
Snowflakes, sleet, and yes graupel were falling from the sky today. Graupel is not a made up word. It is an actual term for a type of frozen precipitation. It occurs when supercooled water droplets in the atmosphere freeze upon contact with a falling snowflake.
Here is an image from the NWS in Chicago that best illustrates the difference between sleet and graupel.
You can see even visually there is a clear distinction betwween the two. Sleet is a bit more clear while graupel has a milky looking color to it.
In terms of the temperature profile of the atmosphere, and what it takes to develop both sleet and graupel, there must be a warm layer (above freezing) in the middle of the atmosphere, sandwiched between two cold (below freezing) layers. And that is exactly what we saw today.
Here is a great image that best depicts this courtesy of NOAA:
Here are the different temperature profiles that form snow, sleet, freezing rain and rain.
Winter Weather Advisories have been issued as a result of this wintry precipiation. Your First Warning Weather team has the latest: Today’s Forecast