Both domains must have a wrfinput_d0x file at the start of the model run.
All static and meteorological data for the nest(s) are obtained from the nest's input file.
Advantage: Nested domains benefit from high resolution static fields.
Disadvantage: Nested domains must start at same time as the coarse grid domain.
Namelist parameters:
     input_from_file = .true.,.true.,

Program flow:

Note WPS can be set up to generate multiple met_em.d02.* files for the nested domain, but only the initial time is required. Up to this point the steps required for both case "i" and "ii" above are identical. The nested domain will always gets its boundary conditions from the coarse domain, so no wrfbdy_d02 will be created.