There is a sequence of precipitation that is very characteristic of the passing of a warm front during the winter months in areas where winter conditions are cold. The diagram below shows this sequence in an idealized fashion.
Imagine living on the eastern side of the front (right side of the image) and the warm front is approaching from the west. If conditions are right, you will most likely experience the following sequence of precipitation: snow which turns to sleet, which turns to freezing rain, which ultimately gives way to rain as the actual frontal boundary passes. Note that the sequence is the result of varying depths of warm and cold air layers. Look out for this sequence this winter.