This is one of those updates where I get to take much of what was in the last update and throw it in the trash. A perfectly enjoyable mission however since all of the very important changes are positive. Though we still have a threat of some milder temperatures late next week, the next 10 days looks much snowier and even days I was convinced would be dry, now look powdery. Even in the warmer longer range outlook, there are some positive developments that will likely prevent it from getting too mild for too long.
Happy to report that I did get Monday right. Beautiful sunshine and still a little bit of wind but not nearly as blustery as the past weekend, particularly Saturday. That sunshine will be with us again early Tuesday with even calmer winds but clouds will advance into northern Vermont by the afternoon and snow will begin falling out of those clouds Tuesday evening. In yet another example of a storm system shifting northward, this one comes as a result of a temporarily dominant southeast ridge in the jet stream which will allow temperatures to climb well into the 70's across Georgia and portions of the Carolina's. None of that mild air will intrude on our New England winter but the push of warmer temperatures will be felt in the form of overrunning snowfall. 2-4 inches of snowfall by first tracks time Wednesday with an additional 1-3 inches during the day. A powder day is thus the result since temperatures should hold steady in the 20's Wednesday.
A northwest wind should allow snow flurries through Wednesday night but a the formation of a major storm east of Cape Hatteras should quickly cause precipitation over New England to diminish and allow some sunshine to return Thursday. This brings us to our next change - the polar vortex, or at least a piece of one. In another surprise, a piece of stronger arctic chill will jam its way underneath the persistent block in the jet stream over the Hudson Strait. We will begin to feel the effects of that late Thursday with temperatures dropping from a high of near 20 early in the day to below zero Friday morning. Blustery winds and bitterly cold temperatures will then be the story for Friday with readings only in the single numbers a wind chill values well below that. Winds of near 10-20 mph will continue into this upcoming Saturday with temperatures recovering into the teens and then Sunday should feel much nicer with minimal winds and temperatures in the 20's. Both weekend days should feature healthy amounts of sunshine although that could change.
If all those changes aren't enough to digest, I've got a big finale consisting of the potential for a big storm early next week. Just getting a piece of that polar vortex early in the weekend is enough to slow the advance of milder temperatures and as the polar jet retreats late in the weekend, it will create a inviting stage for a winter storm Monday. Models have been hinting at something for a few days actually but the last few cycles of model data suggest more cold air on the playing field. Long way to go still and this outlook could go many directions but I like the direction we are headed now and hope it continues.
And yes, the trend in the longer range outlook still does include the threat of some milder temperatures but some interesting developments do accompany that. The persistence of the -AO would be the generalization you could make. We've talked about the importance of having that index counter the negative impacts of an agitated Pacific jet stream which it has continuously this winter. More specifically though, ensembles are again showing a block in the jet stream north of Alaska with a possible result consisting of arctic air flooding much of western Canada and parts of the western parts of the United States. Though that doesn't help Vermont directly and immediately later next week, it may eventually if the effect of all this is to push the persistent blocking over the Hudson Strait eastward back to Greenland. That is way off in the distance however and I am having enough trouble getting the next 6 days right.
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