Pattern expected to relax a bit allowing for a post Thanksgiving warm-up but hope remains for early Dec !

A widespread outbreak of cold across the U.S. has been impressive in its expansiveness and its ability to produce the 6-7 feet of lake-effect snowfall in those climatologically favored areas just south of Buffalo. The snow band that set up over Watertown, NY was equally impressive and somewhat unusual because of the persistent impact north of the Tug Hill Forest/Plateau in towns such as Watertown eastward to the Five Ponds Wilderness area of the Adirondacks. Lake-effect snow hounds are used to seeing the Lake Ontario snowband set up in the area bound by the famous snow towns of Barnes Corners, NY to the north and Redfield, NY to the south. There was a lot of thunder reported with both snow bands illustrating how unstable the boundary layer of the lower troposphere was in this airmass. Water temperatures in the eastern Great Lakes have been in the upper 40's or even low 50's while temperatures 7,000 feet up were in the high teens. That will make for a very dynamic weather situation and it certainly did. 

Aside from the deep snow in some of those snow-belt regions we've seen a widespread outbreak of below normal temperatures. As I suspected, the Vermont high country has put together a nice consecutive stretch of sub-freezing weather conditions but it's not nearly enough to erase what was an historically warm start to the month of November (November is still likely to be substantially above normal). The western two thirds of the U.S. are experiencing a rather cool month however and this is driven by an EPO which started positive at the end of October, but has recently plummeted to an index of -4 just as Buffalo was getting clobbered with snow a few days ago.  One can think of the EPO as a measurement of jet stream activity in the Pacific and has proven to be a very useful indicator of weather over much of North America. This along with many of the other key teleconnection indices were quite favorable for winter weather this past week but will neutralize as we advance toward December. The EPO will remain marginally favorable and there suggestions in the ensemble data of more split flow type of activity which is very encouraging going into winter. At the same time we are expected to lose high latitude blocking support over the next two weeks. The jet stream is not expected to go entirely zonal but won't at all favor widespread below normal temperatures in eastern North America. The most discouraging indicator is the PNA which would suggest that cold and snow is more favored over western North America as the calendar turns to December. Most of the ensemble data was showing this through the weekend but backed off today and was suggesting that cool weather would linger over the northeast even as the west receives both snow and colder weather. Keep expectations in check in early December, it can be a disappointing time in Vermont and I think this year offers more hope than most. 

I am not especially excited about the potential storm after the Thanksgiving holiday. This should be a rain event with the cold having receded well before the advance of any precipitation with this system. The storm is also expected to amplify way too early leaving the only chance for frozen precipitation at the end of the event. I fully expect to keep our few inches of snow through Thanksgiving but not through the upcoming weekend. Seasonal outlook is a work in progress but it's coming. Thanks for the continued interest.