Upcoming storm system may speed up & deepen - some severe potential

Well, this one came out of left field.

The Storm Prediction Center has released a day 3 categorical outlook which puts some parts of extreme south west lower Michigan into a Marginal Risk zone for severe weather.  This is in response to the NAM depicting the upcoming storm system (which first looked like it was going to affect us Monday) as moving much faster and deepening considerably.  This increase in vorticity combined with stronger-than-expected instability may drive severe weather in this portion of the state.

Those deep reds and purples are beginning to show up in both the supercell composite and the significant tornado index for extreme western lower Michigan, however 

So far, I don't see too many indications of it going any further north, though there is always that chance. If it does, this would be quite the surprise event to supplement the craziness we had last Sunday.  There are indications to me that, at least conditionally, the setup could favor strong tornadoes if it really got going.  Despite this strong setup, ongoing convection from the previous day could temper the atmosphere.  There are indications of this being the case in the current short term models such as the NAM4KM, so the next few runs will be quite crucial to determining whether or not the storm situation will be bust or boom.

Regardless, this adjustment to the forecast now favors widespread rain Saturday morning, and widespread thunderstorms throughout the state on Sunday.  So much for dry and quiet!