ETA 00Z still seems on track. The 500mb vort that was evident on the 18Z ETA is now gone, and the front appears to have slowed down by a couple of hours, putting the timing close to what he 12Z ETA had. Lapse rates also appear a bit lower this go around - from 6.7C/KM (850-500) to 6.2C/KM.
CAPE does climb to near 3000J/KG tomorrow afternoon, but there is no real significant trigger around, so I don't see a real big thunderstorm threat (unless some outflow boundaries from todays storms linger around). Main show should be late tomorrow evening across western lower, extending hrough the early night across the east. ETA drops CAPE of significantly between 21Z and 00Z, but this is due to how the ETA handles SFC moisture (it pretty much scours things out around and after 00Z). Adjusting for this change in moisture (averaging the 21Z and 00Z dewpoints), I still come out with CAPE values around 1800J/KG through 03Z across many locations, before the front comes through. Forcing along the front is also very strong - as evident by the 700-500mb vertical velocity field, and the SFC wind/moisture convergence. Dry air intrusion is also very intense - with <30% slamming into the region... Given that... I am Still expecting a line of severe thunderstorms, as helicities are now lower than the previous ETA runs - 150m2/s2 to 200m2/s2...
As for a derecho event... I think it's still possible given the intensity of the of the 500mb height falls (i.e. rapid intensification), good wind fields, and very strong forcing. I believe 1800J/KG would be enough to sustain a serious line of storms through the night time hours WED into THU... Not really sure how to calculate speed of the storms if they were to form into a derecho type event, but it does seem that it could outrun the cold front and perhaps arrive a bit sooner than expected across central/eastern lower MI...