Basics for Running the Model

Below is a description of the program flow during a typical model run:

WPS

geogrid.exe creates terrestrial data from static geographic data that is obtained from an external data source (this is available to download, and will be discussed in the case studies).
ungrib.exe unpacks GRIB meteorological data (that is obtained from an external source) and packs it into an intermediate file format.
metgrid.exe interpolates the meteorological data horizontally onto your model domain. Output from metgrid.exe is used as input to WRF (through the real.exe program).

WRF

real.exe vertically interpolates the data onto the model coordinates.
wrf.exe generates the model forecast.

Detailed information on all components are available in the WRF Users' Guide. Peruse Chapter 3 for details on WPS, and Chapter 5 for details on WRF.

Should I run geogrid or ungrib first? It does not matter in which order these 2 programs are run, as they are independent of each other. Additionally, re-running one does not require that you must re-run the other.

Before we run a specific case, let's first look at some details regarding each of the individual components.

Basics – GEOGRID