There's some pretty good WAA at 850 mb the night before. It's also quite moist. Thus there is most likely going to be some overnight/morning convection due to isentropic lift from tonight's LLJ that will undoubtedly form along the high plains. This is confirmed by checking isentropic charts from the NAM. There's a pretty deep layer of moist and sloped isentropic lift across much of NE (including parts of SD) overnight. I saw lift between 301 K and the 313 K.
How this overnight/morning convection evolves will play a significant role as to the extent and location of diurnal convection on Tuesday. If the morning convection persists and is large in scale, it will most likely reinforce the warm front and shove it farther south. In this case we'll be more likely to see a significant instability gradient along the front with very low cloud bases on any diurnal storms that form north of the front. If this convection is weak, short lived, or small in scale, the warm front is less likely to be impeded and will probably make it farther north and will probably also attain a more NW-SE orientation. The environment north of the warm front might not be so stable either. It's more likely a more significant event could ensue in this scenario. It's most likely the actual evolution will be between these two extremes, so you will want to pay close attention to how outflow from these overnight/morning storms impact the location of the warm front.
