LTNG

     LTNG is the ending valid time for lightning data, the time increments (in
     minutes going back from the ending time) and the corresponding colors for
     the lightning data, and the positive and negative markers to display.

	End time|time increments/colors|positive marker/negative marker

     The ending time is the latest time for which lightning data will be
     plotted.  The ending time is given as a GEMPAK date/time string.  Any 
     missing items from the string will be filled in by the system time.  The
     ending time may also be LAST.  LAST will use the system time and plot all
     lightning data for the preceding times as defined by the time increments.
     ALL is not accepted as an ending time for lightning data.

     The time increments and colors may each be specified using either a list
     separated by semicolons or a range in the form first-last-increment. 
     Time increments are given in minutes going back sequentially from the
     ending time.  The number of time increments must be the same as the
     number of colors.  If no time increment and color are given, a single
     time increment of 5 minutes with a default color of red will be used.  
     If the range format is used for the time, an increment must be specified.
     If the range format is used for the color and an increment is not 
     specified, an increment of one is used.

     The marker data includes the marker type, size and width, separated by
     semicolons.  The default marker for positive strikes is a plus sign, and
     for negative strikes a minus sign.  Default marker size multiplier is
     one, as is default width.
     

     Examples:

	LTNG  = 991130/2315|1/5

 		All lightning data will be plotted in yellow for times 2314Z
 		and 2315Z.  Default marker values will be used.

	LTNG  = LAST      

 		All lightning data for the preceding five minutes will be 
 		plotted in red.

	LTNG  = ltng=991201/0000|10;20;30;90/2;17;5;3|4;1.5;2/6;2;3

 		Lightning data for 991130/2350 to 991201/0000 will be plotted
 		in red; for 2330 to 2349 in orange; for 2300 to 2329 in yellow;
 		and for 2130 to 2259 in green.  Positive strikes will be 
 		plotted as squares with a size multiplier of 1.5 and a line
 		width of 2; negative markers will be plotted as diamonds with
 		a size multiplier of 2 and a line width of 3.