Case Study of the High Impact 6 Jan 2017 Icing Event across Central Mississippi

On Friday, January 6, 2017, a portion of the NWS Jackson, MS forecast area was severely impacted by a significant ice event. During the event, heavy sleet fell on relatively warm road surfaces as temperatures dropped well below freezing, which led to the crippling effect of slush freezing into solid ice on the roads. Numerous motorists were stranded for up to 36 hours when portions of the interstate system were shut down, and further complicating matters was that most schools and businesses were open. This event unfolded in a complex manner, across a region of the country that is extremely sensitive to small amounts of winter weather.

While winter weather was forecast for several days leading up to this event, there was high uncertainty regarding precipitation type, location and overall amounts. Low forecast confidence resulted in outlooks and products that underplayed potential impacts, even though numerical weather guidance suggested that a more impactful event with heavier accumulation was possible on a small scale. As the event unfolded, two rounds of mostly heavy sleet fell within the Interstate 20 corridor, including the Jackson metropolitan area where up to an inch accumulated on paved surfaces. While the heaviest ice accumulation did end up occurring on a small scale as suspected, location and timing resulted in major impacts to travel with nearly disastrous consequences.

This event illustrates the complexities of forecasting and communicating the various uncertainties for winter events in the Deep South and how subtle changes can substantially change expectations. We will investigate how forecast uncertainty and timing may have worsened the impacts for this winter weather event, and how messaging could be improved to lessen impacts in future events.