A powerful upper-level trough will swing across the Central U.S. today, firing severe storms from Illinois southwest to northern Oklahoma.  Ahead of this feature, a 30+ knot low-level jet will intensify over the warm sector through afternoon into evening, which will provide ample low-level shear for tornadoes. Combined with strong instability along and east the cold front, 0-1 km EHIs will build to above 3 across the entire region, with the strongest values over north-central OK.  The only limiting factor for tornadoes today will be whether storms can remain discrete along the cold front, especially across northeast Missouri and Illinois, where storm motions are less normal to the boundary.  Further southwest near the base of the trough, upper-level winds will have a more westerly component, which should allow storms to more easily move off the cold front and remain discrete/supercellular.

The question over the latter area is initiation, since much of the positive vorticity advection with the trough has shifted off to the east.  The RUC fires storms in north-central OK near 21z, but the NAM has relatively little convection over north-central OK into southeast KS by 00z.  Given the expected instability, weak cap, and strong surface convergence along the front, I'd say storms are a good bet even across the southern end of the focus region.  The Storm Prediction Center has issued a slight risk, with a 5% tornado area from north-central OK into IL.  If initiation appears imminent, I will strongly consider chasing the northern Oklahoma part of this risk area, especially since Hurricane Bill looks like it will recurve.  Check out Live Streaming this afternoon for any teams documenting this event!  Stay tuned for updates.