UC -- Grids and contours upper air data
  UC parm level map time <keywords>
  UC p1-p2 l1-l2 map t1-t2 <keywords>
Parameters:
  parm  | T(C), TD(C), Z(m), STR, ZS(m), P(mb), VOR, ABV, DVG, SPD(m/s),
          THAE(K), THA(K), MIX(g/kg)
  level | SFC, 1000, 925, 850, 700, 500, 400, 300, 250, 200, 150, 100,
          TRO1, TRO2, MAXW
  map   | state P.O. abbreviation, DEF, MID, NA, SAT, USA (def=DEF)
  time  | observation time, HH or HH:MM:SS (def=0 if current time is
          between 0 UTC and 13:15 UTC; otherwise def=12)
  p1-p2 | parameter difference used in contouring
  l1-l2 | level difference used in contouring
  t1-t2 | time difference used in contouring
Keywords:
  CINT= | contour interval (def=parm dependent)
  COLOR= | graphics color level; use negative number for dashed
           contours (def=2)
  DAY= | year and day, YYDDD; use YYDDD-YYDDD for day differences
         (def=current)
  GRA= | graphics frame number for display (def=current)
  GRIDF= | destination grid file number (def=from IGU SET)
  LAT=min max | latitude bounds; use when DEF is specified for the
                map parameter
  LON=min max | longitude bounds; use when DEF is specified for the
                map parameter
  MDF= | IRAB or RAOB schema MD file number; use two values (f1-f2) when
         contouring differences (def=last digit of current day plus 10)
Remarks:
  If you do not specify keywords CINT, COLOR, DAY, GRA, GRIDF, LAT, LON
  or MDF, the string table is searched for strings of the same names.
  If those strings exist, UC uses their values.  If keyword or string
  MDF is used, its value is stored and accessed in the string named
  RAOB.  If the command gives unexpected results, use TL to list the
  string table or TD ALL to delete it.

  Advection (ADV) or divergence (DVG) of a parameter is done by
  appending with ADV or DVG (e.g., TADV, SPDDVG).
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