December 7, 2012 Short Range
Over the weekend, a cold front will be moving through the Midwest and Ohio valley. This will be a mainly rain event with a chance of snow showers on the backside of the front. The image below shows the vorticity seen at the 500 mb level with a indicated area of enhanced positive vorticity advection. This will cause widespread rain showers Sunday afternoon. The rain showers over Indiana should be light, as the front will not intensify until moving into Kentucky and Ohio.
After the front moves through the area, a change over from rain to snow may occur early morning Monday. The image below shows left over precipitation Monday morning at the time surface and 850 mb temperature are expected to reach levels conducive to snow over the West Lafayette and Indianapolis area. If snow occurs Monday morning, it will be light and is not expected to accumulate on the roadways, with a possible of a light coat on the grassy surfaces. After the precipitation ends the temperatures for the rest of the week will begin to recover out ahead of the next front.