Short term forecast remains cold but with limited snow, while challenges remain in the longer range

We have a relatively tranquil blog update which includes an ever so slightly colder outlook in the short term, still some challenges looming beyond December 13th and only limited chances for new snow. Beyond the clipper system Thursday night, a weak impulse and some warm advection is expected to spread some clouds and some light snow into the region for a time late Saturday and Saturday night. The story for the next few days is simply the cold weather however which appears now to be the coldest of the season so far. The arctic air mass will keep temperatures in the teens for much of the day Friday, provide for some blue skies late in the day and set the stage for sub-zero readings Friday night and early Saturday. Saturday will also see some sunshine but only enough to boost temperatures up to around 20 before clouds move in. Sunday's readings will approach 30 as the arctic air erodes somewhat and we get some limited sunshine on the heels of what should be a light accumulation of snow Saturday night if at all. 

Looking at the big picture, the story for the next week remains the tightening Pacific jet and the rapidly increasing EPO index. Though the models hedged and debated for a time on the intensity of the EPO change, it is expected to more or less max out around the 12th or 13th and then weaken somewhat beyond that. A shift of that magnitude is going to cause a substantial response from the standpoint of actual weather across North America and unsurprisingly, the biggest is the arctic air going into retreat-mode. Interestingly, in spite of milder temperatures across a large portion of the midwest and plains, northwest flow at jet stream level will keep it on the chilly side across New England for almost another week. The deep snowpack that remains doesn't hurt either. Barring a miracle, we won't taste any part of the big southern streamer Sunday into Monday and snowfall through the middle part of next week will be minimal, though we may be able to squeeze out an inch here and there. 

Once we move toward the 14th and 15th the thaw questions loom. The good news here is that it remains just a question. Though we know how limited the availability of arctic cold will be by this point in time, the southern branch of the jet is still a force to be reckoned and will likely keep the storm track to the regions south, likely stunting the intensity of the mild air. Yes, it's within the possibility spectrum to miraculously turn this potential thaw into some sort of winter weather event but it's asking a lot with eastern Canada almost entirely devoid of serious cold. 

The aforementioned conundrum is likely to continue beyond the 15th. The pattern doesn't appear overwhelmingly mild but glaringly non-arctic. Certainly a scenario very common during El Nino winters, and although this ENSO isn't nearly the magnitude of 2015-2016, it has strengthened in the last few weeks to about 1.2 C above normal. On the flip side, we just recorded a massive snow cover number in the Northern Hemisphere during the month of November. This colder feedback will help to counteract some of the warmer feedbacks caused by the state of the ENSO going forward or at least that is my hope.