Example g_plots.tbl to plot MM5 sigma-level data on isentropic 
                    levels:
                  TIME 
                    LEVELS: FROM 
                    1993-03-13_00 TO 1993-03-14_00 BY 6
                    PRESSURE 
                    LEVEL MANDATORY: FROM SFC TO PTOP (ignored)
                    PRESSURE LEVEL NON STANDARD: FROM SFC TO PTOP BY 3 (ignored)
                    SIGMA LEVEL: FROM 3 TO KMAX BY 5
                    TITLE: SOC - MM5V3 
                    - EXAMPLE PLOT TABLE FOR SIGMA DATA
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                    PLOT | FIELD | UNITS |  CONTOUR | SMOOTH || OVERLAY | 
                    UNITS |  CONTOUR | SMOOTH
                    T/F  |       |       
                    | INTERVAL | PASSES ||  FIELD  |       
                    | INTERVAL | PASSES
                    -----|-------|-------|----------|--------||---------|-------|----------|-------
                    TI330| PV    
                    |Km/s^3Pa|    1.   |   
                    0    ||         
                    |       |          
                    |
                    TI330| P     
                    |  mb   |     4.   
                    |   0    ||         
                    |       |          
                    |
                    -------------------------------------------------------------------------------