Edited: forgot to include the "over" for over fill in first 2 scripts.

#700 to 850 thck APPROXIMATION OF RAIN/SNOW LINES blue=snow, red=anything is possible, green=rain
erase
analyze,sdif=1:2 stor=2 hght h850 stor=1 hght h700
analyze,over fill color=0:255:0 grtn=1555 fill color=255:0:0 grtn=1525 fill color=0:0:255 grtn=0
analyze,cont cint=15
stamp
#1000 TO 850 thck APPROXIMATION OF RAIN/SNOW LINES blue=snow, red=anything is possible, green=rain
erase
analyze,sdif=1:2 stor=2 hght h000 stor=1 hght h850
analyze,over fill color=0:255:0 grtn=1310 fill color=255:0:0 grtn=1290 fill color=0:0:255 grtn=0
analyze,cont cint=10
stamp
This script is on the board, thanks to Peter for providing:
#Snow script (1)
#S=(H850-H700)+2*(H1000-H850)
ERASE
ANALYZE, OVER FILL LSTN=4179 COLOR=050:200:255 FILS=0 SSUM 4:7 STOR=7 SDIF 5:6 STOR=6 HGHT H850 STOR=5 HGHT H1000 STOR=4 SMLC 3:2 STOR=3 SDIF 2:1 STOR=2 HGHT H700 STOR=1 HGHT H850
ANALYZE,CONT EQUA=4179 LINE=2 COLOR=255:000:000
ANALYZE, OVER FILL LSTN= 4500 GRTN=4179 COLOR=000:200:050 FILS=2
#ANALYZE, CONT CINT=100 COLOR=100
STAMP
#wetbulb below zero area - for areas of possible "wetbulbing"
erase
analyze,over fill fils=3 lstn=0 bulb
analyze,cont cint=2 color=200:0:0
stamp
P19