The influence of large scale circulation, represented by the first three rotated EOFs and their associated PCs of wintertime mean sea level pressure, on winter maximum daily precipitation over the North America during 1948-1998 has been investigated. The observed relationship between the circulation and the extreme precipitation is then used to derive projected changes in extreme precipitation in the future due to circulation change caused by the increase of greenhouse gases as simulated by CGCM2 conducted at CCCma forced by IPCC "IS92a" forcing scenario. It appears that impact of human induced circulation change on winter maximum daily precipitation in 2050-2099 is comparable to the observed response of extremes precipitation to the occurrence of El Nino in the second half of the 20th century.