Early October monstrosity? GFS predicts a dragon

Retiring the thunderstorm outlook for the fall may have jinxed us.

Something wicked has appeared in the later hours of the last couple of GFS runs. And I do mean wicked. Allow me to tell the tale of the picture that the GFS is painting.

A wintery blast of some of the first truly cold air of the year (30s, potentially even sub-30s) looks to descend into the central plains and upper Mississippi Valley.  A truly frightening 120kt+ negatively tilted upper level disturbance would be the driving force behind this cold blast.

Upper level winds associated with this trough are forecast to reach 120kts as of this latest run. 

At 18,000ft near the tops of the storms, winds would also be very strong.

North of this, a monstrous upper level surface low would develop with a central pressure to the tune of 980-990 hPa/millibars would develop.  To the southwest, a heat dome of 85° temperatures and 65° dewpoints...

85° on one side and 35° on the other makes for a potentially ugly situation.

Peak intensity as predicted by the latest GFS shows a negatively tilted behemoth at 990 hPa in the ideal position to wreak havoc on Michigan.  Timing of the day would not be the best for big storms according to this forecast, though.  

This is a witches brew for a very strong late season tornado outbreak, which at this point looks as though it may target the Great Lakes region. The biggest reasoning for my concern at this point is the sheer numbers in terms of temperature differential. If you have 80-85° temperatures with 60-65° dewpoints in place, and you blast 30° dry air into the region, you might as well be setting off a bomb in the atmosphere.

A lot of factors would have to come into alignment in order for this to produce severe weather, not the least of which is timing.  If the timing of the day is off on this one, we may wind up with nothing more than a few storms and a cold windy rainy mess. Position is also a big factor. This forecast may also shift significantly eastward as has happened previously with long-range GFS-predicted storms. Even if shows up where it is, there's no telling yet if Michigan would be the state to bear the full force, or if it would instead target Chicago/Indiana like in November of 2013. Just looking at this, though, I would not be surprised if I wind up pulling the outlook widget back out for one last event yet this year.