An upper level impulse in the jet stream is going to ignite what will become a big east coast snow event on Thursday, the biggest of the season so far for all of southern New England. The storm will take shape as an anafrontal wave initially Wednesday night but evolve in to a significant low pressure system as it encounters the relative warmth of the Atlantic Ocean early Thursday. Heavy snow (and some rain over SE Mass and the Cape) will persist through much of the day and the thinking for a time was that this snow would not make it into central and northern Vermont but this thinking is getting a challenged as of Tuesday afternoon. MRG is likely to taste the northern edge of this wintry weather system and receive a 1-3 inches of snow while considerably higher amounts fall further south. Friday will be a mostly snow-free day but very cold, one of the coldest days in a month actually with readings starting the day below zero and struggling to get past 5 degrees during the day.
The upcoming weekend had significant questions a few days ago and we hope to answer all of these in a mostly positive way. Much of the eastern United States, as expected, will see a big push of mild weather and much above normal temperatures both Saturday and Sunday. Can this mild air bully its way into New England however. A "yes" answer would have meant some spring-like skiing for a day, a "nay" answer means new snow. I am relatively confident as of Tuesday afternoon that the "nays" have it. The mild push will mostly fail in its attempt to reach Vermont but will instead provide the necessary overrunning surface for new snow either Friday night or during the day Saturday. I can't promise a ton of new snow, but a few inches is certainly better than 45 degrees and slush. A storm system is also expected to impact the region during the day on Sunday. Cold air will have a very tenuous grip on the region by then, but it may have just enough of a grip to keep temperatures cold enough for snow or a snow/sleet mixture.
Beyond the weekend, we got have lots of interesting details that need to be resolved. Generally speaking however we have seen some fundamental changes in the outlook over the past two days that are very positive for us Vermont skiers going forward through the end of the month of February. I'll summarize them bullet-point style here.
1) The emergence of split flow in the jet stream over the next week which will include an active southern branch of sub-tropical jet stream. This should begin manifesting itself in about a week's time but should help keep things very interesting from the middle of the month forward.
2) The decisive turn of the NAO and AO into negative territory. We will see the polar jet recede this weekend but the aforementioned indices will help allow the cold air to return for time by around the 15tth-16th of the month.
3) The EPO which had turned adversely positive and will be so through the weekend, will return to neutral and perhaps even go negative in two weeks.
Though some of this was mentioned two days ago, the ensemble data is more decisive today. The details beyond a week still look a bit cloudy however. We might have some snow on the backside of Sunday's system if we are provided with some low-level instability capable of putting our upslope machine into action. The middle part of the week might see some snow from a small disturbance but the real question surrounds a potential system later in the week. This would be the first stemming from the more active southern branch and could quite possibly turn into a big event or could be nothing. The indices mentioned above should help the holiday weekend be wintry however and this is a significant change and a much needed one, relative to how we looked 2 days ago. It's a good lesson also to not overweight ensemble data beyond about 12 days particularly this year. There have been a few big false alarms both on the warm and cold side over the past two months.