Pre-Xmas thaw looks brief and outlook for the holiday week appears colder

The season at MRG is officially underway as the snow continues to fly. More of the good stuff  is expected on Monday as mild air makes a significant push toward the region. Though it may commonplace in our circles to cast negative aspersions on a "mild push of air" it is often a very effective way to produce snow. I don't expect Monday's "overrunning" snow to produce epic powder, but 2 or 3 inches is likely along with temperatures in the teens and 20's. This mild air will make a brief interlude into the region on Tuesday. Temperatures will sneak above the freezing mark for a few hours at the base of the hill but will likely stay below freezing above 3000 feet or so. Elevations sensitive rain/snow showers should impact the region during the afternoon before colder air changes all precipitation to snow Tuesday night. By Wednesday, temperatures will be back in the 20's and snow showers should freshen the mountain with a few new inches.

The bigger and more important questions obviously involves the upcoming holiday weekend and beyond. We certainly have some concerns. Though we are unlikely to come out victorious in every one of what should be a few intriguing weather situations during the last 10 days of 2017, we could still actually do quite well and score at least one big snow before the new year. We have the excellent fundamentals mentioned in prior posts such as the loose Pacific Jet and ridge/block across the Alaskan peninsula and we are also dealing with the byproducts of what is now a rather stable La Nina. The pattern will amplify as it should as we approach the holiday weekend and arctic air will come cascading southward into the United States. This initial amplification will occur too far west however and allow a storm to cut up through the eastern Great Lakes around the time of December  22 and 23, a Friday and a Saturday. We should see some snow from this system intially and then some ice and then it looks more and more that a period of rain on Saturday along with above-freezing temperatures.

As this is happening a very strong arctic high pressure center will build across the western two thirds of the country and advance east. Some very cold air is likely to build across the area around the Christmas holiday but the ridge across the southeastern United States is expected to be persistent enough to keep the mild air close along with the a general area of storminess. It's a muddled weather picture and is likely to change but there are indications of a 2nd significant storm Chistmas Eve or Day. With colder air on the playing field, precipitation is more likely to stay frozen though nothing is set in stone.

Arctic air is then shown to overwhelm the pattern in the days following Christmas and the outlook thus appears colder on Tuesday and Wednesday. Can we generate another storm later in the week ? Absolutely. It typical La Nina fashion, the ridge across the southeast will encourage any storminess to track a bit closer to us than it would otherwise in such a pattern. Though models aren't showing any hard evidence of big snow around New Years weekend as of Sunday morning, one is certainly possible along with the continued presence of cold air.

Still wintry for at least a week but thaw is possible around Xmas

Arctic air controls the state and has helped to make for some beautiful wintry scenery and a few good ski days as well. Vermont in particular will in fact be one of the most wintry states in the country over the next several days. Opening day has been officially moved up a day to Friday December 15th. It will be a chilly start with temperatures just below zero degrees. Some early sunshine will help boost readings back into the teens but clouds should be on the increase ahead of a polar disturbance in the jet stream. This disturbance will spread some light snow into the the mountains Friday night and re enforce the arctic chill for the weekend. There are a few hours where atmospheric profiles (and wind direction) are very favorable for lake//terrain enhanced snow at MRG. This would occur right around opening on Saturday and would fall in addition to the light snow Friday night. I am going to take a stab and say 3-6 inches of snow by midday Saturday but forecasting the lake/terrain induced stuff is a challenge so that range is a rather soft one (though I would be quite surprised if we end up with less than two). Conditions should dry out late Saturday followed by a bluebird Sunday with readings climbing up near 20 in the afternoon after a sub-zero start.

There was some talk and some Iphone forecasts suggesting snow during the middle of next week. I think our best chance for a decent accumulation comes from the warm advection induced precipitation Monday. It doesn't look more than a few inches but it does look powdery. Tuesday looks like a day where some warm air could sneak into the region. Don't think rain is very likely but temperatures could certainly push past the freezing mark in the valleys and challenge that same mark on the lower mountain. After this "relaxation" in the pattern, colder air will retake control of the state and more terrain/lake induced snow is possible Tuesday night into Wednesday.

Ok, now moving on to the Christmas weekend where tons of very tough questions need to be answered. Hemispherically speaking, there are going to be some encouraging fundamentals or teleconnnections anchoring the weather pattern, the biggest of which is a block over the Alaskan Peninsula. That said, the crest of this block is setting up a bit further west than we would like it. It will leave Vermont in a war zone of airmasses. Though we could win a battle or two and I fully expect we will, we could also lose one. The pattern amplifications during the current week and to some degree next week will favor Vermont ski country but these will shift westward by Christmas Eve. As a result I expect a series of storms to track right at the state. A reasonable expectations right now as that we get some snow and wintry weather from one and  rain and a thaw from another. Hard to pinpoint exact dates but the first such system should come within a day of Christmas Eve with another a few days after that. The situation is obviously fluid. I am not married to particular scenario and fully expect the outlook to shift around a bit.

Got one in the bag, more is on the way but lots of uncertainty in the outlook going forward

Our first significant snow has successfully blanketed the region Tuesday and more is on the way. We should expect to see additional snowfall through a good party of Wednesday along with blustery conditions and temperatures generally in the teens but it does not appear to be the greatest case for terrain/lake snow at MRG. There's only a shallow layer of low level instability over northern Vermont Wednesday and some wind shear above this unstable layer. That said there is plenty of lingering moisture. 2-5 inches Wednesday on top of the 10-14 Tuesday and Tuesday night should bring storm totals to a foot or more though snow conditions at the summits will be pretty wind blown thanks to strong northwest winds.

A series of small weather systems will keep most of the snow action to the south Thursday and Friday. Temperatures will be quite cold and possibly find their way below zero for the first time this winter season on Friday morning. Readings will only rise into the teens both Thursday and Friday. Temperatures will moderate on Saturday, opening day, and some snowfall will return from a rather benign looking weather feature. A few inches is certainly possible on Saturday.

Uncertainty rises rather quickly after Saturday. Models are having a difficult time wading through the specifics of a pattern that is expected to relax Sunday/Monday and then re amplify Tuesday and Wednesday. There are varying scenarios being advertised and for now I prefer what appears to be the colder one. Dry arctic air will re establish control of Vermont's weather Sunday ahead of a mild push of air and a weather system Monday. Snow or a snow to ice situation should accompany this milder push of air which and its yet to be determined how substantial this precipitation event might be. Colder air then re establishes control of the regions weather Tuesday into Wednesday and some terrain/lake induced snow is possible as this happens.

Ensembles continue to go back and forth for Christmas week. This is turning out to be a very difficult forecast. Conditions in the Pacific will flirt with adversity in the middle of next week but the EPO is expected to slide back into negative territory as mentioned in the last update. A loose jet (negative EPO) in the Pacific is a very critical component in keeping arctic air a part of the weather picture across New England and many other places. In addition, a nice looking Omega blocking feature in the jet stream is still the expectation across Alaska. The position of this feature is very critical. If it sets up shop too far wet across the Alaskan Peninsula it could invite a push of warmth along the east coast. If block is positioned along the Alaskan/Canadian border, Vermont will be very wintry, cold and possibly snowy. I think Vermont has a good chance to be on the wintry side of the action but I'll admit it's a little closer than I would like it be.

First significant snow Tuesday/Wednesday and I am starting to like the Christmas outlook

Got a few inches in the bag and should have plenty more to come in the coming days and even weeks. I'll readily admit that at the time of the last blog update, there was legitimate concern that this entire pattern might flop around Christmas Eve. Just in the last 36 hours or so, there have more definitive indications that the jet stream in the Pacific Ocean, though tightening slightly next week, will loosen substantially right around Christmas Day sending the EPO index back into more favorable negative territory. The 6-year consecutive stretch of Christmas thaws is thus in jeopardy but not yet eliminated (eliminating it now would obviously jinx it and ensure 60 degree weather by the 26th).

First thing is first however, a significant storm system on Tuesday. Was surprised on Sunday to see the National Weather Service in Burlington lower accumulations  (2-4")for Tuesday and only advertise the event as "light snow". Perhaps it reflects some lingering uncertainty regarding the nature of the event. Though models have zeroed in on snowfall Tuesday, the storm's eventual strengthening or "bombing" in the Gulf of Maine remains a question. Both domestic models seem a little less bearish on the "bombing" than foreign counterparts. Sorry about the puns, it's just the way the sentence came out. Even without significant downstream strengthening, we will see more than 2-4 inches.

Snow should begin around daybreak Tuesday and for a time, should fall moderately and perhaps heavily for a few hours. I think the strengthening in the Gulf of Maine will be more substantial and though I think snowfall might taper to flurries by late Tuesday afternoon, 6-10 inches should be the expectation for high country locations like Mad River Glen. Snow will re intensify Tuesday night and continue as snow showers Wednesday as some of the coldest weather of the season so far builds across the area. There has been lots of talk about big time lake effect snow Wednesday because of the thermal situation around the Great Lakes. This applies to Lake Champlain as well and snow showers and squalls should be the result providing the mountains with additional accumulations. I am going to retain a little caution and suggest 8-16 inches over the two day (Tuesday/Wednesday) period but my gut wants to say 10-20". I'll leave both forecasts out there for now and let the chips fall where they may.

Temperatures will be in the teens and single numbers Wednesday and Thursday and we expect the east coast to get impacted by another clipper system later Thursday into Friday. Lots of uncertainty persists regarding this situation and snowfall is possible over a broad area but not guaranteed for anyone. The European model has been relatively consistent in its assessment that the storm and its snow will remain to the region's south but this model has its miscues over the last few weeks so it will be worth watching.

The pattern is expected to relax around the weekend of the 16th and 17th though cold weather will fight to remain in place across interior New England. Will a mild push of air coupled with a storm system late in the weekend bring another wintry weather situation to Vermont ? Could we see a limited stretch of above freezing temperatures ? Several possible outcomes here but either way, we should see colder weather return by Tuesday December 19th and persist through the middle of next week.

The longer range was already discussed but to reiterate, I was very encouraged to see varying ensembles suggest a weakened Pacific Jet as we head toward Xmas weekend. In addition, there are indications of a full fledged Omega blocking structure in the jet over Alaska and this more or less guarantees the presence of arctic air for New England and plenty of other places.

Let the December snowfest begin !!

Certainly a few rather important updates this morning and most of them are pretty darn positive as far as new snow is concerned in Vermont. So this Saturday storm is now "a thing" in the parlance of our current times. I need to be shamed somewhat for dismissing the possibility a few days ago. Models have such a difficult time dealing with fronts that so often linger around the Atlantic Coast. I've described the coastline as a "tinderbox" which it is, but a major consequence is that if models miss even slightly on one wave of jet energy, errors accumulate exponentially and 48 hours later the forecast picture is hardly recognizable. The wave of energy in question is causing snow in some rather unusual locations across Dixie. Its more of a disorganized but still rather significant conglomeration of moisture as of Friday but by Saturday it will have evolved into a garden variety coastal low pressure system. Snow will be falling across the Mid Atlantic and spread into southern New England during the morning hours.

The forecast picture for Vermont has changed profoundly as a result. We expected Saturday to be dry and quite possibly feature a good bit of sunshine. Though we may see the sun very early on Saturday, most of the day will be cloudy and snow should arrive by mid-afternoon. Across SE New England, this has become a very significant snow event and accumulations across a sliver of eastern Massachusetts could reach the 8-14 inch category. Snow will be on the lighter side across the Mad River Valley but still fall at a rather steady rate for several hours and total 3-6 inches by Sunday morning. The situation is still very fluid and models have been trending toward a stronger system and a farther west storm path. If this continues, accumulations would obviously be higher.

The storm Saturday will swallow much of the energy from the Midwest clipper we discussed a few days ago. That said, snow showers and even snow squalls are still likely on Sunday yielding some additional accumulations and leaving us feeling rather wintry as temperatures hover in the high 20's and then drop into the lower teens Sunday night. A weak area of high pressure will try and build across the region on Monday but flurries remain possible particularly in the morning.

I advertised "50 percent" or a "coin flip" on a big storm for Tuesday into Wednesday of next week. This probability looks closer to 80 percent as of Friday. Some disagreement persists relating to the track and timing of the event but the concept of a bombing New England/Gulf of Maine clipper system appears to be a universally accepted outcome. The clipper will spread its snow into Vermont Tuesday morning if all goes according to plan and the storm would strengthen. The disagreement mostly revolves around the track of the storm and would certainly impact overall snow accumulations and the positioning of dry air but not the overall forecast of snow. Accumulations could still wind in the modest 4-8 inch category if the American/Canadian model is correct in its assertion that the track of the storm is right over or even north of the state, but storm totals could reach a foot or more if the European solution is right and the storm path is closer to the southern New England coastline. Think we could probably iron out all those uncertainties within two days.

Bigger surge of cold weather arrives on Wednesday as the snow tapers to flurries. Though temperatures might be in the 20's Tuesday night, we should see readings in the teens for much of the day and drop into the single numbers by Thursday morning. There are some additional snow possibilities later in to the week and into the weekend for a variety of reasons. The pattern is then expected to relax somewhat on Sunday Dec 17th into the early part of the following week but the AO will remain a very dominant player on a continental level (negative AO) and cold air should remain available across New England even if temperatures modify substantially further south. A storm system is certainly possible in this time frame as the temperature gradient between the warm and cold intensifies.

We should see another good southward surge of cold weather just prior to the Christmas holiday weekend and I am ready to suggest that the 20-23rd of the month will be on the wintry side. Can we break this 6-year streak of a Christmas thaw. Certainly possible but those horses are not in the barn quite yet.

Trying to make sense of a wintry forecast

Depending on when you read this, we are about to start or have just started what we hope to be our first extended stretch of below freezing temperatures. We should see our first flurries Wednesday evening and night  but snowfall will be minimal by the looks of things, may take a few days before amounting to anything significant. Snowfall will mostly be confined to the Great Lakes Thursday in the traditional snowbelt areas. That said, we expect a band or two of snow to make it over the Adirondacks and get slight boost from the warm waters of Lake Champlain. This should be enough to whiten the mountains around the Mad River Valley but the best snow Thursday appears to be from Stowe northward to Jay where I would expect a few inches.

Snow prospects for the weekend did not move in the direction that I would have preferred. Moisture and energy associated with a nearly stalled front off the Atlantic coast will linger too close to the coastline though not close enough. I referred to this the other day as "baroclinicity" and it often becomes the focal point for moisture and storms. Unfortunately, when energy is consolidated just off the Atlantic coast as is the case this weekend, the weather will remain quiet across interior New England and devoid of snowfall. We are in fact between two systems Saturday with the energy offshore representing one area of storminess and clipper across the Great Lakes concentrating snowfall well west of Vermont. Decaying moisture from this clipper system will finally reach Vermont later on Sunday or Sunday night bringing what I would expect to be our first light accumulation to the region but the bigger possibilities are laying in wait and may at that point be consuming most of our attention by the end of the weekend.

The storm situation in question involve the Tuesday-Wednesday time frame or December 12th and 13th. The pattern will relax somewhat in the wake of the passage of the late weekend clipper but as this is happening, the jet stream will be gearing up for another, even bigger amplification. We don't have any southern branch jet energy to work with but a series of shortwaves will accompany this next incoming surge of cold weather. Can any of these shortwaves be the match that lights the fuse ? Models, all of them, have been erratic and inconsistent in answering this question. The European model had a classic Gulf of Maine bomber on the run released Tuesday afternoon but it was not shown Wednesday morning. The American model seems to be back and forth on this question every 6 hours. The lack of consistency in the operational model runs simply reveals the uncertainty regarding this storm at this juncture. The ensembles, as of early Wednesday, continue to suggest strong hints of a significant snow for all of interior New England. My interpretation ? It's a coin flip - 50 percent.

Even if we end up on the wrong end of this "50 percent", we should be on the receiving end of at least some lighter snowfall. We should get some of this as early as Monday the 11th thanks to a weak area of overrunning moisture  and then some additional snow Tuesday from the clipper. Modestly cold air follows for Wednesday and Thursday of next week and then we have the possibility of more snow on Friday December 15th and into the weekend.

The longer range looks about the same as it did several days ago. Though the PNA appears as if it wants to relax as we approach the Winter Solstice the AO will remain decidedly negative and there are no glaring indications of jet tightening in the Pacific though this situation will bear watching in the days to come.

A few days away a big stretch of winter and maybe a week away from significant snows

It might be a little mild out there but early December is early December. Its always very dark and typically there isn't a lot of snow on the ground. We expect that all to change within the next week or two and we are going to try and zero in on some details but it's still a challenge as we remain several days away from a significant snow.

After a series of sub-freezing nights, we can expect about a 48 hour stretch of above freezing temperatures (somewhat less than that above 2500 feet) beginning Monday afternoon and persisting through Wednesday afternoon. The front marking the end of the thaw will also mark the beginning of a  new and very improved pattern. The front will also bring a few hours of modest rainfall to the entire state Tuesday evening along with 45-50 degree temperatures. The rain is all done by Wednesday, the above freezing temperatures are done by Wednesday evening and away we go.

The initial blast of cold will have modified substantially before reaching New England and is taking the scenic root across the Ohio Valley. We can still expect flurries to commence by later Wednesday and continue into Thursday though I am skeptical about accumulations amounting to much. The real question relates to the lingering baraclinicity (a fancy word for temperature boundary) that will remain just offshore. It won't take much to ignite a coastal system on the 9th/10th which is why I described the environment to be a "tinder box" in a tweet the other day. Opinions vary on the viability of storm but Vermont has some optionality. We can get a dose of snow from a potential coastal system which would more likely be Saturday or receive a potentially greater gift if a dymanic clipper system becomes the dominant feature and produces both synoptic snow and lake/terrain enhanced snow Sunday. Can't guarantee anything this early but if I were a betting man, I would take the "over" on at least 6 inches by the end of the weekend.

Not too many changes to the longer range outlook as of the weekend which is a "no news is good news situation". The pattern looks excellent, propelled mostly by a very negative Arctic Oscillation and a big assist from a positive PNA. Another significant "clipper-like" disturbance is likely to bring additional snows to the high country in the Monday/Tuesday time frame ahead of what should be a more significant surge of cold air. Since the air isn't overwhelmingly cold (modestly cold) we get the added benefit of keeping the boundary layer on the unstable side. Particularly intense shots of arctic air can be both very dry and bring a shallow very stable layer to the atmospheric preventing snowfall. All that said, I expect additional snowfall later in the week.

The looming question and I mean the very looming question relates to the Christmas holiday and whether or not this pattern can continue into Christmas week. I can promise good things until about the Winter Solstice but patterns such as this are often interrupted during La Nina years and do not typically last a month or longer. There aren't any ominous signs way out on the horizon but lets be cautious for now.