Deal with it,
Cosgrove
Beware of warmer, calmer forecasts this week and next. I make this remark because many of the numerical models cannot correctly figure what will happen in situations where stronger high-latitude blocking ridges exist, concurrently with an equally impressive subtropical jet stream. The evolution of a Bering Sea and Greenland/Iceland couplet ridging is well underway. Positive height anomalies in those positions favor the formation of cold 500MB vortices in Alberta and below Newfoundland. The USA result is that colder than normal temperatures are probable in all but Texas and the Dixie states. Climatology for this type of event allows for stronger cold frontal passages through the Midwest and the Eastern Seaboard above Interstate 40. With the active southern branch adding energy, there can be phased events off of the Mid-Atlantic shoreline. Much like what the GGEM panels show December 20-22. Not only is there the chance for a rogue snow event then (along and west of the major cities), but warm-ups will be hard to maintain. I suspect that another risk for an important precipitation event may occur between Christmas and New Year's. That cold pool setting up east of Sable Island NS creates a window for redevelopment, which could be especially potent if the subtropical jet stream energy joins in the fray. Be very careful when handling cold air and storm transitions over the next two or three weeks. Note that the heat ridge complex in the Gulf of Mexico and Florida gets suppressed after this week!