Most of these variables are directly to analogous to their counterparts used for plotting surface and upper air data. One addition is the notion of a valid time in the GDATTIM variable. Since model output has both an initial or verification time and a valid time, we need an additional field appended to the nominal model time to represent when the forecast is valid.
GFUNC represents a scalar quantity to be plotted, while GVECT represents a vector quantity. GDPFUN encompasses both scalar and vector quantities. The GFUNC/GVECT/GDPFUN variable can either be a variable name which resides within the grid file, a grid which can be derived from other fields found in the grid file, or one of the mathematical or meteorological operators listed in GPARM. When using the operators listed in GPARM, remember that fields marked S require a scalar variable, and fields marked V require a vector.
Well, as you will see there are many more variables, but these will get you going.
Lets do some
exercises!