Above is the 07Z run of the RUC for 28 February. Around this time the frontal system was passing through central Indiana and bringing with it some very high potential for severe weather. As you can see the surface temperatures varied from 20 degrees Celsius to 0 degrees Celsius with winds converging across central Indiana.
Above is the calculated hourly temperature advection for 08Z on the 28th as well, smoothed with sm5s in GEMPAK and contoured with 3 degree celsius intervals. As you can see, there is huge cold air advection just west of Indiana.