Skipped Segment
 

Tuesday I fly PHX-ORD-MSN on US and then AA. It is a one way booked ticket. Weather in Madison calls for a 90% chance of storms. Will I have any problems if I skip the ORD-MSN leg on AA? I have almost a 2 hour layover so I can almost drive there in that time. This flight is regularly delayed and/or cancelled. Would it help to call? I'm not doing this for a financial reason as MSN was significantly more expensive. Would it have any impact on EQM accrual?

If PHX-ORD-MSN-??? is all one itinerary/PNR and you skip ORD-MSN the rest of the itinerary will be auto cancelled

It's a one way with a connection. There is nothing after ORD to MSN. I'd basically only fly PHX to ORD.

As long as you don't make a habit of missing the last segment, there's very little likelihood of any fallout at all; you would merely earn PHX-ORD miles as usual.

Thanks. That's what I figured. I'm certainly not going to make a habit but if I'm playing the weather game Tuesday afternoon, I may just skip it.

I'd just let them know in ORD if you decide to forego the final leg.

I've done that before (even on a round-trip ticket) and there was no problem.

I'd only recommend doing that IF there were a major delay or cancellation of your second leg (I've done this too, going MSN-DTW-FWA RT and DTW-FWA was delayed). But for a one way OP is fine.