Much of the central part of North America has been getting the wrath of the current El Nino for much of this month consisting of much above average temperatures and little snowfall So far Vermont has managed to escape much of this, we've continued to get snowfall over the northern Vermont high country and temperatures have been at least shouting distance from average though not especially cold.
Unfortunately, mother nature is sending us its own past due notice and is seeking repayment. Monday's storm has all of El Nino's worst elements and Vermont does not appear positioned to escape any of it. The best news I can provide readers regarding this storm is that the nasty weather should avoid weekend skiing activities. Intervals of sunshine on Saturday with excellent visibility and calm winds can be expected to go along with temperatures in the 30's. Sunday will be cloudier and a little milder but the rain is expected to mostly hold off until the evening.
Monday's big storm is a powerful southern streamer originating in the Gulf of Mexico. It will bring with it an abundance of moisture and then continue to intensify along the east coast, grabbing relative mild marine Atlantic Ocean air and depositing it deep into interior sections of the northeast and a large chunk of Quebec. There was already a glaring lack of cold air in the existing weather picture and the model consensus is taking this powerful storm and tracking it up the Delaware Valley and ultimately west of the entire state. If this holds, it will produce an ugly result of windswept heavy rain. The precipitation would begin Sunday evening in more tranquil fashion but winds will be gusty by Monday morning and both temperatures and dewpoints are expected to rise into the 50's. We will need to find a way to avoid the wind, the heaviest rain and the high dewpoints because this combination will wipe out much of what was an outstanding start to the season it pains me to say. Still a slight bit of room for this storm to maneuver into a less disastrous outcome, but some wet weather will be hard to avoid and the current outlook could feature over an inch of rain and even some isolated flood risks.
There's a small area of cold that will become entrained into the departing storm from the west. Prior to Friday, sporadic model output was suggesting that the incoming cold could ignite a 2nd, colder low pressure area capable of producing snowfall. Models took much of this away Friday, but this remains a possible scenario in the mid-week time frame.
There is some better news in the long range. Though there isn't a mechanism, or a high latitude blocking element present to really chill the North American continent down, the pattern still appears more promising toward the holiday time frame because of an emerging positive PNA structure and the potential to produce split flow out of this jet stream structure. When I talk about split flow in the jet stream, I understand I might be spinning a few heads, but I love split flow and this is why. You have one part of the jet stream producing a ridge in the jet stream over western Canada while the other provides a continuous flow of moisture across the southern and central Rocky Mountains sometimes referred to as the pineapple express. When the two branches of the jet stream converge you have one component (north) capable of delivering some Canadian chill while the other delivers the moisture. It's a good combination and it looks we could manage to work ourselves into such a setup around the holiday and especially toward the New Year. Not a cold outlook, but we are entering a part of the season where we don't need an overwhelming supply of cold, just need a little.
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