Greetings- I am attempting to display theta in either X-Z or X-Y cross sections. I tried the following but it got hung up on "lev" define pr=(1013.0/lev) define prcalc=pow(pr,0.286) define theta=tmpprs*prcalc where "mpprs" is the temperature variable. I also subsituted "Z" for "lev" and it still did not work. Any thoughts ??? Many Thanks- John NWS, Anchorage