WTIMINC is a parameter in the fort.15 file that is the time increment between meteorological forcing data sets (in seconds) in input files like the fort.22. This parameter and the line on which it appears depend on the value of
NWS. For a detailed breakdown of what goes on this line in the fort.15 file, see the supplemental meteorological/wave/ice parameters page. Broadly,
WTIMINC is required for
ABS(NWS)>1 unless you are using one of the parametric vortex models for meteorology. Relatedly, note that when
NWS=-14, a second parameter,
WTIMINC_12 defines the time increment for meteorological data for the OWI-formatted files.