Hi Justin,
In Practice mode, I copied all the grids from Official and then ran the FB Procedure for Days 1-7. The Diurnal Tool seemed to work for the portion of the Today T grids from 12Z through 1 hour before the current time as these turned green. The rest of the T grids were not edited and this is when the AlertViz pop-up banner stating "Error running procedure Diurnal" popped up.
Mike