Lots to talk about once again in this ever evolving weather scenario. I think we had a bit of a better handle on things during the last update but it's time to expand on details in what should an exciting finish to January. A moisture-starved clipper system spreads its limited moisture into the region Friday resulting in some occasional light snow and a very light accumulation. This system, however, brings with it a classic New England arctic sneak attack. These particular intrusions of cold are unmodified by the Great Lakes and are thus quite vicious and often poorly identified on the medium range models. Cold will arrive later Friday and send temperatures on the mountain plummeting to near -15 on the mountain by Saturday morning. Limited sunshine during the day Saturday and lighter winds will make the day feel somewhat more comfortable as temperatures recover to above zero.
We then turn our attention to a stronger clipper system which is expected to pass through the Great Lakes Saturday night into early Sunday. As it does so it will grab ahold of a very weak but very important southern branch jet disturbance. These two systems will gradually phase with the southern branch feature using the jet dynamics from the clipper to expand its field of precipitation. There is dissention amongst the available model data on the exact track of this storm around New England. It isn't a big disagreement but the window of heavy precipitation associated with this storm, although significant, is very narrow and thus a difference of 100 miles in the storm track has a large bearing on the eventual results for our beloved mountain. The last Euro model tracked the developing system over New Hampshire with its ensemble members showing a track closer to the seacoast. Either of these scenarios deliver 10-inch hit for most of VT Sunday and Sunday night with additional snows Monday. Both the American and Canadian models were just off the coast with the track and given this aforementioned narrow band of snowfall being indicated with this storm, the result given this scenario would be a light accumulation. A blend of the results and the mountain would be on the edge, but should do ok. My guess right now is that it's about 40 percent for a 10-plus inch snow late Sunday, Sunday night and Monday and a 70 percent chance for at least a few inches. Just to clarify, the snow would arrive on a milder Sunday and should begin falling with temperatures in the high 20's. If we can land in the sweet spot, the snow would continue Sunday night and taper to lighter but continuous snows Monday.
Seasonable temperatures follow in the wake of this system later Monday into Tuesday. By later in the day Tuesday a clipper system passes to the region's south and brings most of its limited moisture well to the regions south. I don't think we are going to miss too much out of this guy. More seasonable but relatively dry weather continues for Wednesday and then into early Thursday.
This brings us to the end of the week and the re-ignition (at least we hope) of the all important southern branch. Believe me, I would throw a housewarming party for it if I could ! Over the last two days, we have seen with better clarity, indications of a significant weather system exiting the Southern Rockies during the middle of next week and gather substantial amounts of moisture as it crosses into Texas and begins to head east or northeast. Plenty of differing scenarios with what looks to be a storm exhibiting lots of potential. None of the models have yet to yield any consistent results regarding a possible outcome, but they are suggesting an outcome which in and of itself is important. If we were to get a hit out of this it would be Friday Jan 23 and would include some significant snowfall. There is certainly a chance for a miss and there is a slight chance of snow and ice (The Euro had that this morning but was farther south on the afternoon run).
Every indication is then pointing toward the development of a massive upper ridge building across western North America and ultimately expanding into the Yukon, Alaska and into the Bering Sea. This is the kind of pattern we more or less expected at the beginning of the winter and we should get a good dose of it for at least the last week of January. This means the re-arrival of the polar jet, the southward advance of the "Polar Vortex", lots of cold air, and a few clippers to go along with it. The Euro Ensembles showed a result liked the best that included the continued presence of the southern branch of the jet stream, especially toward the very end of January. Lots of good things here, enough that we can handle a bad surprise should one show up at the last second.