Forecast trends drier with chilly temperatures prevailing though Dec 12 and a possible thaw Dec 14-15

Colder temperatures have arrived and a few inches of snow came with it. Tuesday was the beginning of an extended stretch of sub-freezing temperatures, but the forecast has trended drier over the past 48 hours. We also are expecting some of the cold to retreat somewhat during the middle of the month, but this "retreat" doesn't appear especially severe right for now and temperatures appear just slightly above average in the period starting December 13th to about the solstice which is about as far out as we can reasonably prognosticate.

Wednesday will finally feature more than a glimpse of sunshine which will help boost temperatures into the 20's along with relatively calm winds. Clouds are expected to return Thursday and some light snow is expected from a clipper system Thursday night. Honestly, I had higher hopes for this system as it appears totally deprived of moisture and appears way too far north for any late coastal strengthening. Still, it will bring with it another charge of arctic cold, rivaling the Thanksgiving cold outbreak with temperatures below zero Saturday morning and rising toward 20 Saturday afternoon. Saturday will feature more sunshine however which is a welcome sight during what is the darkest days of the season.

Forecasters are watching the big southern streamer which is expected to slam the Gulf Coast with rain and thunderstorms this weekend. By Sunday evening, the storm will continue to be a sizable weather producer centered near the Carolina coast. Given the right configuration in the jet stream, this storm could make a northward turn and cripple the entire northeast with snowfall but the circumstances just aren't right this time. The polar jet is retreating and a large ridge in the jet stream is expected to build over south-central Canada just as the storm reaches the coastline. This simply does not provide a clear northward or northeastward avenue for this storm to travel and its speed is expected to slow, perhaps even stall and thus keeping the impact area smaller. Some snow could certainly fall across inland portions of Virginia and West Virginia but at this point I would be surprised to see this storm become a serious New England impact, even in southern sections though one can never say never, not with northeast weather.

As mentioned in previous posts, the jet in the Pacific will be tightening and strengthening and will force the polar jet and arctic air to go into retreat mode. This appears to be a slow process right now however for a couple reasons. First, given the time of the year and the low sun angle, it will take some time for the cold air to erode and will need some advection to do it. Secondly, the Pacific will go into full "evil empire" mode. No, we could certainly do a lot better but we've also seen a lot worse. Temperatures are thus expected to remain below freezing through at least the 12th or 13th of December. Barring a miracle from the aforementioned coastal storm, snowfall will also be minimal but there is a small disturbance capable of delivering a light accumulation this weekend.

We are likely to see a round of above freezing temperatures and rainfall sometime around the 14th-15th of the month which coincides fairly well with the peaking EPO (Pacific Jet strength). There doesn't appear to be any mechanism to provide for the return of arctic air after the 15th but the pattern doesn't appear to be terrible. If I had to guess, temperatures would likely remain above average but we might be able to reintroduce the possibility for snow with what looks to be the continuation of a stormy pattern overall.