A couple of points..

The area's which are really going to be impacted are probably other than tiled Prime Cornbelt ground.. although that too could be delayed.. but it's not expected to be by much.. for long... at this point.

South Dakota is running out of time to get ALL of it's HRS Wheat in on a timely matter.. not that we need all of it.

We don't have much of ANY tile out here on the fringe..  not that it would matter.. but the damage on our HRW Wheat was already done last fall.. some of those 30 acre lakes... are now drying up.  And we could.. believe it or not.. use a drink this week..  (Careful what I ask for..)

The Added Corn acreage is from the Fringe.. what was it 800 k each from the Dakota's?  plus the rest.. 

So that alone is gonna be a drag on the US Yield.. we got a lift as we reduced corn acres back to the Core.. now it's expanding and bringing the lower quality back in.. IF we can get it in on time.

An overall later start will reduce yield as was the case in the upper midwest last year.

edit add:  The ENSO.. yes is not suppose to turn back to dry for us.. but the goody of the shift has probably occured.. and may continue to be.. favorable.. However, odds are increasing that it will shift back to the dry side..

The LAST time we had this much flooding in the upper Missouri basin.. 2011.. South of I-70 we fried.. and then followed that up with the yield hit in 2012.. NOT saying thats gonna occur this year.. but probably the "next" thing will be the Southern Plains drying out.. later this summer.. fall.. 2020..??

in other words.. the pattern continues.

fwiw.