The strong but complex storm system that brought snow to the west, heavy rains to the central US and major ice accumulations to western portions of the southern Plains is continuing to bring rain and snow to the Midwest as the main upper air Low now over the Rockies re-energizes the storm system during the next 24 hours. The storm and associated frontal boundaries will move eastward with most Precip moving off the east coast by Friday – with Temps continuing to average above normal across much of the nation. While there is still significant uncertainty on just how warm it will get across the eastern US going into next week, there are likely to be some record level warmth in the northern Mississippi Valley across to New England between late this week and the middle of next week. 

With little change in the primarily progressive upper air pattern anticipated, above normal Temps are likely to continue thru at least mid-month (and probably thru most of the month) across much of the nation). The exception to this outlook will be over portions of the inter-mountain west and Gulf coast state region where above normal Precip and below normal upper air heights will keep Temps closer to or even below normal. 

EL NIÑO PEAKS BUT IMPACT WILL CONTINUE THRU THE WINTER 

SST anomalies across the tropical EPAC have changed little over the past week, and remain near ‘Super El Niño’ levels in the benchmark 3.4 region where the latest weekly ONI update came in at +3.0˚C. With the MJO quite weak, and no major Westerly Wind Bursts forecast during the next 2 weeks, it appears likely that SST anomalies will gradually decrease during DEC to around +2.7˚C and closer to +2.0˚C by late JAN (unless, of course, all the operational and climate models are wrong). However, a solid El Niño atmospheric pattern is likely to persist thru the entire winter since there tends to be a significant lag in the atmospheric flow pattern response relative to changes in SST’s. 
http://www.wunderground.com/blog/SteveGregory/the-storm-that-keeps-on-going-with-unseasonable-warmth