Happy 2018 folks. We sent 2017 off on a frozen, bone chilling, ice blast. It's been the most impressive cold wave to hit interior New England since 2004, besting even the readings experienced during February of 2015. On the mountain, nearly every hour of the last 5 days of the year were spent below zero and obviously it felt a lot colder with the added effect of the wind. As expected, the PV smashed our chances for new snow. Too much shallow, stable cold the surface and way too much jet energy aloft aimed in the wrong direction.
But as Bill Belichick might say, we're on to 2018 and there is plenty to discuss in the upcoming 10 days. Subtropical energy off the east coast of Florida will allow a low pressure center to form and deposit snow in some highly unusual locations such as Jacksonville, FL or Savannah, GA or Charleston, SC. The storm will start as a relatively innocuous system but as it continues to move up the coast Wednesday January 3rd, it will gather strength and ultimately receive a giant infusion of polar jet energy in the form of an eastward advancing clipper system. And then it's bombs away and I mean big time ! We've seen some big storms in the 12-year history of the blog but I don't remember anything quite like this in the winter season. There are some indications that the storm could deepen to 950 mb south of Nova Scotia. To put this in perspective, the Valentines Day Storm of 2007 was around 977 mb and our Ides of March storm this past year was about the same. Historic Hurricane Irma strengthened to about 915 mb and Superstorm/Hurricane Sandy was in the 945 -950 mb range.
Models have converged on a track that is a big too far east for big snow in Vermont. Given the storms power, this is somewhat fortunate for coastal locations who will nonetheless get some severe winds. The track has trended a bit farther west the last two days but remains on the order of 100-plus miles east of Cape Cod. In spite of this, the massive size of the storm and the decaying conveyor of moisture from the clipper system should allow some light snow to fall across Vermont. Snowfall looks to be in the 2-4 inch range right now Thursday, Thursday Night and early Friday but the window remains open just a crack for big changes in case of a big shift in the track of the storm. Terrain/lake snow again looks minimal later Friday and Friday night as another massive surge of cold gets pile driven into New England. This late-week cold blast may take the crown as the coldest of the season with readings as cold as -25 during the upcoming weekend. The shallow, stable nature of the cold though is what kills the oragraphic snow so barring a big change in the direction of the storm, new accumulations over the first week of 2018 appear minimal.
The jet stream is still expected to relax somewhat but not entirely after January 6th. We don't want a total capitulation, we just want the polar jet to loosen its tight grip just a bit and we should get exactly that around the time of January 8th. That particular Monday-Tuesday time frame appears to be the period where we receive the impact of our next weather system. A bit early to tell what effects this system might bring to Vermont but at least some snow is likely. More cold is also likely in the wake of this storm for a few days before we could get tested with a more significant push of milder air.
The middle of the month looks intriguing. There have been indications for some time that a thaw is possible but ensembles have shifted somewhat and are now suggesting that a jet stream ridge across western North America stretching north through the Yukon and into the Arctic might be equally influential. Because of the latter, cold air will be plentiful in eastern Canada and I would expect any mild push of air to receive some rather stout resistance. When met with the right kind of resistance, pushes of mild air can mean additional snow. In summary, I still expect a day or two of above freezing temperatures and some non-snow type precipitation though no major thaw during the middle of the month but significant new snow is also likely. Typical northern New England January weather when you truly break it down.