[idvusers] Contour plot defined by two variables (into defined ranges)

Hi all,

I want to plot the contour of the volumes with a Relative humidity of more than 
95% and Temperature between 0ºC and -20ºC using the NCEP GFS Global 0.5 degrees.

I would really appreciate your help in solving this or even a tip about how to 
do it.

Thank you in advance. 
-- 
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                          Dr. Miquel Traveria
                        Professor of meteorology
                Centre D'estudis Superiors de l'Aviació
                             www.cesda.com
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                        mtraveria.pdi@xxxxxxxxx
                 tel: (34) 977 300 027 ext. 217 or 116
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