Hi,The FV3 core will run as GFS v15 and up. Initially it will use the current GFS grid at 0.25 deg and the change will be transparent.
This was planned to occur in Jan-Feb this year but as a result of the government stoppages the start has been delayed.
Only in about one year will the new grid be introduced.
So... we will be providing FV3 automatically as it starts with the current grid.
When the new grid comes on line we will make the necessary adjustments to provide it
David