I have try too, to work out the difficulties with temp. below 0 cel. in the best possible way, and have now came up with below script.
It works, in a part of the way, in the same manner as Fred's, but I have rule the analyzies out completely in Farenheit with contours of 3 celcius degress converted in Farenheit.
Thereafter I ran a basemap and so - my point - an normal analyze per 3 celcius degrees so I come up with filled in lines and numbers of temp. in celcius.
Of course I still have the problem with temp. below 0 Farenheit (- 17.8 C.) that would have the same colour, but temps. below that value are split up in individual contours and numbers of temp.
Also the temp. colour I have tried to work out in a different way so it almots match the way of GFS forecast.
You can have a look at the my uploaded map (map 3) here to see the result:
http://www.jahla.dk/MelfarVejr/Online/O ... tskort.htm
Thanks to all for your valuable hints
#Analyze Temperatur#
ANALYZE,OVER FILL COLOR=200:005:200 FILS=0 GRTN<0.0 FILL DEGF TEMP
ANALYZE,OVER FILL COLOR=000:000:255 FILS=0 GRTN=5.0 DEGF TEMP
ANALYZE,OVER FILL COLOR=085:085:255 FILS=0 GRTN=10.4 DEGF TEMP
ANALYZE,OVER FILL COLOR=136:136:255 FILS=0 GRTN=15.8 DEGF TEMP
ANALYZE,OVER FILL COLOR=130:235:255 FILS=0 GRTN=21.2 DEGF TEMP
ANALYZE,OVER FILL COLOR=128:255:228 FILS=0 GRTN=26.6 DEGF TEMP
ANALYZE,OVER FILL COLOR=128:255:166 FILS=0 GRTN=32.0 DEGF TEMP
ANALYZE,OVER FILL COLOR=128:255:128 FILS=0 GRTN=37.4 DEGF TEMP
ANALYZE,OVER FILL COLOR=048:255:048 FILS=0 GRTN=42.8 DEGF TEMP
ANALYZE,OVER FILL COLOR=010:255:010 FILS=0 GRTN=48.2 DEGF TEMP
ANALYZE,OVER FILL COLOR=255:240:010 FILS=0 GRTN=53.6 DEGF TEMP
ANALYZE,OVER FILL COLOR=240:228:000 FILS=0 GRTN=59.0 DEGF TEMP
ANALYZE,OVER FILL COLOR=240:210:000 FILS=0 GRTN=64.4 DEGF TEMP
ANALYZE,OVER FILL COLOR=255:174:028 FILS=0 GRTN=69.8 DEGF TEMP
ANALYZE,OVER FILL COLOR=255:142:028 FILS=0 GRTN=75.2 DEGF TEMP
ANALYZE,OVER FILL COLOR=255:134:012 FILS=0 GRTN=80.6 DEGF TEMP
ANALYZE,OVER FILL COLOR=230:115:000 FILS=0 GRTN=86.0 DEGF TEMP
ANALYZE,OVER FILL COLOR=228:092:000 FILS=0 GRTN=91.4 DEGF TEMP
ANALYZE,OVER FILL COLOR=236:066:016 FILS=0 GRTN=96.8 DEGF TEMP
ANALYZE,OVER FILL COLOR=225:040:016 FILS=0 GRTN=102.2 DEGF TEMP
ANALYZE,OVER FILL COLOR=255:045:150 FILS=0 GRTN=107.6 DEGF TEMP
basemap
analyze,CONT CINT=3 COLOR=100
100 LINE=2 TEMP