Looks like we're not getting a mean for the 18Z Ens at present, so it's a case of clicking on the individual members to see what they're showing.
For newbies, click on Pertubation/Disturbances...1,2,3 etc
http://www.meteociel.fr/modeles/gefs_cartes.php?ech=0&code=0&mode=0&carte=1