Can't say I'm not impressed with the 12z GFS on Tuesday in the PPA-CDS-FDR corridor. Those are some pretty hellacious looking soundings with a very high degree of turning between the surface and 6 km, very low LCL heights (we'll see how moisture behaves) and a pretty classic arcing dryline configuration. Synoptically, especially at 500 mb, there appear to be quite a few similarities to significant early season High Plains events in the past with a large, slow-moving ULL generally near/just east of the Four Corners. Dryline position will probably end up being west of where the GFS depicts it, and there seems to be some concern regarding displacement of the stronger 700 mb flow away from overlapping the effective warm sector.
Oh, and there's definitely some indication of after dark problems, of which this region is no stranger to with early season events.