The Northern Indiana office of the National Weather Service (IWX) conducted a webinar for its partners at 3:30 p.m. ET Monday, January 31, to discuss a winter storm forecasted to hit its area in the following days. Here is a summary of the information shared during the initial briefing and subsequent question-and-answer session.
Update: IWX later published on YouTube a recording of the briefing given during the webinar described here.
IWX meteorologist expected to upgrade the existing winter storm watch to a winter storm warning for at least part of the IWX forecast area by 3:30 p.m. ET Jan. 31. Update: IWX issued a winter storm warning for some of its counties at 3:21 p.m. ET. Visit the IWX web page for details.
IWX plans to issue a new multimedia briefing via YouTube Wednesday morning and conduct a second partner webinar Wednesday afternoon.
Forecasters expect the event to begin with a light wintery mix in South Bend Tuesday evening, with rain elsewhere, eventually changing to heavy snow in all areas, as indicated by the timeline graphic above.
Forecaster confidence on winter storm timing is high. Uncertainty is in the transition from rain/sleet/freezing rain to heavy snow, especially along and south of U.S. 24.
IWX shared the graphic above regarding snowfall total for the first of two rounds of snowfall and cautioned partners that the forecast accumulation numbers are very likely to change between now and the beginning of the storm.
IWX shared the graphic above regarding probabilities of heavy snowfall and commented that the storm could be on the order of a one-in-five-year or one-in-ten-year event.
Winds are not forecasted to be significant during this first round of snow Tuesday night and Wednesday. That snow will be fairliy wet and heavy and therefore unlikely to blow and drift.
IWX forecasts a lighter, drier snow Wednesday night through Thursday. Combined with wind gusts forecasted to reach as high as 35 mph, significant blowing and drifing of snow is forecast, especially on east-west roads in rural and open areas. Whiteout conditions are possible. Roads could drift back over shortly after snow plows pass through on Thursday.
Wind chills are forecasted to be below zero by Thursday night, causing a potential hazard for any motorists stranded in snow.
IWX forecasts ice accumulation to be brief in most areas, and not a great impact. Ice amounts will be less significant than heavy snow.