Probably because that might give us a positive NAO and thats not good if you like cold winters, also the number of sunspots,the PDO cycle and the NAO being largely negative for the past few years, infact the most negative phase since the 1960's would suggest we are returning to the weather pattens back then, oh and this winter is most definately not set in stone and yes there are many factors pointing to a cold winter, also if your interested a blog by someone called Mark Vogan http://markvoganweather.blogspot.com/, his winter thoughts will be up tommorow at 12pm (1st august).
Thanks, Ryan.