I agree with the warm front area. Winds are veered a bit south of the warm front (MO and southwestward). The strong wave on the 700mb plot at 12z across the plains will progress eastward, leaving much of OK and KS in subsidence. Things don't look too terrible down there, and the surface flow is backed a bit (PNC is 70/61 with a slightly-east-of-south wind). There does appear to be plenty of stratus around, however, so I'm not too hot on instability prospects. With decent mid-upper level flow, and with the low-level winds remaining OK, I do think there is a thread down in southeastern KS, eastern OK, and maybe just into southwestern MO. Flow behind the wave (at 700mb) is poor, which, with the likely veer low-level flow, leaving me looking elsewhere.
The clouds and precip along and north of the warm front across northeastern MO and point east and north is disturbing, and certainly not good for the development of strong surface-based instability. Dewpoints are pretty nice, however, immediately along the warm front in IL and IN. In addition, IR shows cloud tops to be relatively warm in central IL, where reflectivities are still pretty high. So, I'd say that the mess over IL is likely weakening... In addition, sfc obs indicate some breaks in the clouds over eastern MO and central IL. The 500mb isn't very good here, however, and lapse rates on 12z soundings are nearly moist-adiabatic (not good). 500mb temps upstream aren't any cooler, so I'm not sure if the lapse rates will steepen much, except perhaps through large-scale upward motion ahead of the trough. So, since I'm looking for tornadoes, I'd either go with the slightly more backed flow near Ponca City, OK, or, more probable, near the warm front, where the 68/65 with SE wind ob in extreme west-central IN is calling my name (or the 66/63 with mostly cldy skies in central IL).
