Spell Accuracy and persistent movable zone powers

[Mongolia Jones]

A wizard casts cloudkill and omits the center square from the AoE using Spell Accuracy.

Next round the wizard moves the cloudkill 3 squares due north. Does the omitted square stay stationary or does it move 3 squares due north as well?

 

[Dalzig]

I'd rule that the empty spot of the cloud moves with the cloud...

Pure DM fiat though.

 

[Danceofmasks]

You're choosing squares to omit, not bits of the actual zone.
So they wouldn't move with the zone.