ocr: - - - : - * a * - - - - - - -e Am - - - - a : - - a Figure 3.1 Icing profile for the forecast of the environment at Valentine in the North Central portion of Nebraska at 0300 Universal Time, 11 - March 1999. The ordinate units are pressure in millibars. The green curve: IS the relative humidity in percent. The red curve is the air temperarure in degrees celsius. The magenta curve: IS the equivalent potential vorticity - in EPV units.