What type of precipitation occurs with a shallow layer aloft having above-freezing temperatures?

The correct answer is Ice Pellets. Ice pellets form when precipitation falls through a shallow layer of warm air aloft that is above freezing, causing the precipitation to initially melt into liquid droplets. As these droplets continue to descend, they enter a layer of colder air near the surface, where they refreeze before reaching the ground. This results in the formation of small, transparent spheres of ice, also known as ice pellets or "sleet."

The process of formation is key here: the precipitation must travel through layers of varying temperatures where it transitions from liquid to solid. Ice pellets are distinct from other forms of precipitation due to this specific temperature profile and the resulting physical characteristics of the pellets themselves. Rain, on the other hand, does not undergo this refreezing process, and Icy Rain describes a scenario where liquid rain freezes upon contact with a cold surface instead of in the atmosphere. Sleet is often used interchangeably with ice pellets, but it specifically refers to the transition phenomena that occur. Thus, the presence of a shallow layer of above-freezing temperatures followed by colder air at the surface is what leads to the formation of ice pellets.