Yes, this is possible with the latest release of the AFMIT Analysis software whenever the PALETTE TOOL is visible; just press the PgUp/PgDn keys.
To shift the currently defined color palette up or down one digitization level; to shift the current palette up or down one pixel level of 'brightness.' The entire currently defined palette will shift up or down by one digitization/brightness level.
In WTMAIN(the main WeatherTrac Analysis program), select View:Analysis, then Palette:Adjust, or press the F7 function key. (See the menu at the top of the display.)
Contact support@sfwx.com. Indicate your base contact information, AFMIT serial number, and E-mail address, and we will contact you regarding upgrade to the latest release of WTMAIN.EXE (V1.44).