National Weather Service Weather Forecast Office

Rain began to change to snow by early afternoon from portions of east central to south central South Dakota, as some cooler and drier air filtered into the northern and western fringes of the large upper level storm over the central plains.  The greatest accumulations were found through the I-29 corridor in east central South Dakota, then in localized higher elevation locations between the James and Missouri River valleys.  Below is a summary of snowfall reports received by early evening.

Here is a radar image captured during the time of the changeover.  You can see the lower dewpoint air filtering into east central South Dakota highlighted by the red circled numbers, as well as the relative lack of radar returns west of Brookings and Howard.  The scalloped area denotes the area experiencing a change to snow at this time.