2021 starts with a possible friendly 1-2 punch with 6-plus inches likely early Saturday and more possible late Sunday/Monday

In spite of the near 5 degree temperatures Wednesday morning in the MRV, the pattern going forward looks very non-arctic. Jet stream blocking over the Labrador Sea/Davis Strait will become the dominant weather feature on the northern hemisphere chess board and will clear all of eastern Canada of arctic air and likely keep it that way for a few weeks. Temperatures across northern New England are thus going to remain above average until mid-January but this doesn't mean we are SOL. In early December or perhaps in March/April, a pattern this void of arctic cold would likely not deliver much, but we are entering the coldest climatological period of the winter. A pattern consisting of a robust polar jet this time of the year often will suppress storms and snow and leave interior New England cold and dry. Such will not be the case over the next few weeks ! We have to get the storm track to cooperate but we are owed some cooperation in this -AO/NAO setup and we may finally be moving into a time frame when that starts to happen.

The outlook for New Years weekend has continued to improve as you've probably heard. Even New Years Eve, though certainly a lot milder than average, will only see temperatures slightly above freezing in the morning accompanied by mixed precipitation or some wet snow followed by some clearing. 2020 will end mercifully with a nice view of starry skies, some hope in the air and temperatures down around 20 degrees. The juicy weather system for the weekend comes out of Texas on New Years Day and will advance quickly northeast toward the eastern Great Lakes. Early sunshine will give way to clouds in Vermont but the ski day will remain precipitation free and rather calm with readings in the high 20's. The storm in question continues to look farther south and is likely to track over southern Vermont and NOT the St Lawrence Valley. This puts northern Vermont in a much better place for snowfall and minimizes the time we might experience any sleet while reducing the risk for freezing rain or rain.  I would expect the snow to begin around midnight Saturday and continue through much of the morning.  Amazingly, this could be the best snow of the year for northern Vermont ski country with accumulations of over 6 inches by early afternoon. Yes sleet could compress accumulations but even that looks to be less significant according to the latest round of data. Southern Vermont may also see some snow but less than 6 inches and is also still likely to see freezing rain or drizzle during the day Saturday. It won't be especially cold in the MRV Saturday but cold enough with temperatures holding in the high 20's. 

Saturday's snow is not the last of this subtropical, southern branch jet energy which continues to make life very difficult on medium range models.  A trailing wave of low pressure is now expected to form over TN/KY Saturday as the snow is tapering off in the MRV. Ultimately this weather feature will move to the Virginia Tidewater before turning northeastward and strengthening. There is the bare minimum amount of available cold air for this storm and it still might track a bit too far south but it also might not. Snowfall is thus at least possible beginning very late in the ski day Sunday and persisting through Sunday night into Monday. Were it to happen, temperatures would likely hover just below the freezing mark on the mountain making this a wetter snowfall but those details are not worth the effort in sorting just yet. 

Following any potential snowfall on Monday, the first full week of 2021 appears mild but not excessively so. Temperatures are likely to mostly remain below freezing across the high country even as low lying areas experience 1-2 near 40-degree days. Sounds a lot like something you might expect skiing in Colorado and this is likely what we will see through the middle of the month. As far as snowfall for the rest of next week, a moisture starved disturbance will bring the chance for very light snow to northern Vermont Tuesday and then another system may or may not impact the state sometime during the end of the week. The period between January 6-10 looks a little fuzzy with more time needed to sort out details. In a general sense though, it does appear as if the milder temperatures (in a relative sense) could peak during the weekend of the 9th/10th and the week of January 11-15 again appears stormy. It could very well get fun again but we our storms to tunnel underneath the blocking as they will do this weekend. We can do this Vermont, lets make it happen in 2021 !

Base building frozen precip is possible for New Years weekend and early Jan appears mild but not necessarily snowless

We've moved parts of the of the outlook in the right direction, but in the aggregate, we face the same headwinds as we move mercifully to 2021. A large area of blocking/ridging in the stream that stretches from Quebec through the Labrador Sea/Davis Straight, Greenland and all the way to portions of the Arctic Circle has become the big player on the chess board and has broadened its reach to include northern New England. Meanwhile the Pacific continues to be a nag, pumping a lot jet energy and unsettled weather into the western US while maintaining a bit of a road block for any arctic air trying to advance southward. These two features combined are likely to make it difficult on the supply of arctic cold in New England during the first 10-15 days of January. We've gotten a lot of bad luck with storm tracks in December and if our luck improves, we can still score some snowfall even without the cold air because, its January. I've seen a lot of banter that the pattern will mean invariable lake cutter systems and rain, but I've seen versions of this pattern produce. We just need some of that jet energy in the Pacific to undercut the blocking in the jet stream both downstream and to the north of us, a perfectly reasonable ask in this setup.

The storm passing well north of us Monday did manage to make the Sunday night football game white but its impact on Vermont is pathetic. We are simply in the wrong quadrant of this storm. The combination of a little snow across the higher elevations Monday and a very minimal amount of terrain enhanced Champlain snow Monday night will total about 1-3 inches and that's all she wrote. A brief surge of arctic chill will advance into New England by Tuesday morning and make for a chilly day followed by a 5-degree Tuesday night/Wednesday morning. It might be the coldest period we see through January 10 given how this pattern will evolve. 

The conglomeration of weather set to impact the MRV on New Years still doesn't look great but like I said above, we've been trending in the right direction. It will not be the rinse and repeat Christmas debauchery for starters and the American Model, as of Monday morning is showing a scenario that includes a bit of base-building frozen precipitation for the weekend. On New Years Eve however, another surge of mild air will push northward  and push temps above freezing and we could start our day with a few rain showers. Unlike the Christmas weather system however, this storm will not phase with any subtropical energy and moisture and any rainfall on New Years Eve will be light, brief and early in the day. By the time 2021 arrives we are back below freezing and dry. Then we have the subtropical moisture pushing north on New Years Day. The European continues to show that the weather system responsible will track north of the St Lawrence Valley. We would see some ice and a cold rain in this scenario late New Years Day and into Saturday and that's about it. Other models are further south with this storm however as mentioend. The American GFS model performed miserably with the Christmas system a few days out showing a rain to snow scenario. It was essentially off by 25 degrees Christmas afternoon and really missed the personality of the storm. With that said, it's hard to take the snowy/sleety GFS scenario seriously but the Canadian is even further south (it has us missing the precipitation entirely !). I know that's a lot to unpack there, but to summarize, I consider the notion of base building snow/sleet very unlikely yesterday and I would upgrade that to possible today. 

The first full week of January appears relatively mild. This stems from what was discussed in the opening paragraph regarding the limited supply arctic cold in eastern Canada. Temperatures are likely to climb above freezing between January 2nd and January 10th on a few occasions. That being said, it doesn't necessarily mean El Torchy or a persistent thaw and ultimately our outcome will depend on the fate of the what is likely to be our next possible storm between January 7th and 9th. If we get a better storm track, the pattern won't seem suddenly so terrible.

2020 ends fittingly and northern Vermont rounds the bases on misses and then some

 Hope everyone has and is enjoying their holiday this year. I can't say I am especially enjoying this weather or how the forecast has evolved for the upcoming week. The year started out pretty lousy as we lost one of my favorite musicians, the pandemic continues to unleash its own version of invariable hideousness and the holiday week, fittingly, turns into an abomination on the weather side of things. It's both confounding and frustrating since the pattern has and continues to be mildly supportive. The combination of split flow in western North America and an intensifying blocking jet stream structure in southern Greenland is something I'd certainly sign up for knowing nothing else. This particular -NAO and it's associated blocking has migrated too far south and west however and is allowing relative warmth to find its way into New England at least periodically. What is especially unusual is the storm track. Sure, all that downstream ridging in the jet stream can throw up a brick wall on storms and often this results in maritime hang up systems. This brick wall has been set up way too far west and more amazingly, storms are not tunneling underneath as they often do in these setups, saving our beloved ski country of mild intrusions. 5 days ago I was more concerned with the storm on 12/29 and the New Years storm being too far south. Now both appear too far north to be of much good, and in the case of Near Years, it looks quite bad. 

Many places in the central part of the country did experience some wintry weather and snowfall this Christmas, it just wasn't us. The cold air was of a garden variety intensity but managed to push southward and bring temperatures below freezing in the panhandle of Florida Christmas morning. This while Vermont was raining and in the 50's. A modified version of this cold air will bring temperatures back to more seasonable levels over the weekend with some accompanying snow flurries and snow showers. Accumulations will be be pretty minimal however expect for locations from Stowe north to Jay Peak where 1-3 inches are likely. 

The system on Monday 12/28 has wasted all of its potential. This is a storm that might've exploded off the New England coast and subsequently had no place to go in the Canadian Maritimes with all of that downstream blocking; instead, the system is tracking way too north and is way too benign. All of Vermont is situated in the wrong quadrant given this track and valley locations of southern Vermont might only see a cold rain shower or two. The high country around MRV is still capable of procuring 1-3 inches and the incoming cold weather Monday night is accompanied by a wind direction favorable enough for some Champlain/terrrain wind blown powder.  Across valley locations, Monday's temps will make a run at 40 when its not snowing. Tuesday and Wednesday will be seasonable however with readings in the 20's during the day.

Northern Vermont has rounded the directional bases as far as misses this month. We've missed or failed to procure decent snowfall in storms that have tracked too far north, too far east, too far south and too far west. The end of 2020 will, fittingly, feature another system that will track way too far north and west yet again. The same theme applies yet again. Often times storms will tunnel underneath in a negative -NAO set up often missing Vermont to the south or delivering as they did in March of 2018. This storm, like the two predecessors will track way too far north. Very surprising but very 2020. We should be able to keep readings below the freezing mark until New Years eve and we could see some icing but ultimately, precipitation is likely to become rain yet again with 2021 starting way too mild. 

Beyond the New Year I would certainly like to see the blocking structure in Greenland confined to Greenland. Ensembles indicate that the feature is so broad in influence that much of northeast Canada and New England is robbed of its supply of arctic air. This in addition to the obstacles the current weather pattern has given us on the storm track side of the equation. It doesn't appear that we are going to get much help in the near term taming the Pacific so although I like the -NAO, it has to be more cooperative and set up shop closer to home and not intrude on our space. Maybe when the calendar turns to 2021, this will magically occur because 2021 is not 2020.

Scrooge job for Christmas as expected and a downgrade for our potential storm 12/28-29

 No good tidings with our 'nightmare before Christmas' situation. It's as bad as we'd feared. We'll keep temps below freezing through early Christmas Eve but by midday, a modest south wind will push readings into the 40's and the abomination commences in the evening. Though it can depend on where you live in the valley, south winds can really rip down the valley unlike any other wind direction and I fully expect they will. We certainly could see some power outages and a few trees down on Christmas Eve night. Combined with temperatures/dewpoints well into the 40's and occasionally heavy rain we should expect to have any natural snow wiped out. Even our southern neighbors near Okemo and Ascutney who've been living large the past week will take quite a beating with not much left to show for all the good fortune. Just a classic Vermont Christmas Scrooge job ! 

Mild temps of near 50 degrees or even higher will actually linger through a good part of Christmas Day though the rain will have ended fairly early in the morning. The return to colder temperatures will be accompanied by snow flurries Friday night and that should continue into Saturday and Sunday. Farther north, these snow showers will amount to a few inches but our wind direction isn't especially favorable for Champlain/terrain enhanced snow. I expect maybe a fluffy inch or two total over the weekend across the high country around MRV and a dusting in the valley. 

I don't have especially great news in the week leading up to New Years. The storm track has shifted northward according to recent rounds of model data. A surprising turn of events from my perspective since, in this setup, it was actually the reverse I was more concerned with. The negative NAO, fueled by a building and ultimately massive jet stream ridge over southern Greenland will soon become the elephant in the room and I had concerns it would actually suppress storminess and keep the door open for a maritime "hang-up" situation. Still possible but the trend has been moving in reverse. There are many variables on a weather map and when focused on one thing, another thing ends up being missed. In this case, models are keying in on energy in the Pacific diving into the southwest US and amplifying. This would have the effect of steering the jet northward downstream were this to happen. Even these less than ideal circumstances keeps the door open for snow on Monday December 28th, just not as much of it and temperatures will be milder than I would like. It's pretty frustrating but I would stay tuned on the week. If comparing the weather to a game of Texas Holdem, a split jet stream is a pretty good hand to start with, and allows for several potential different winning hands. The "flop" and "river" cards might not help with the 28th but could allow for something later. I would also note that a worst case scenario for the 28th appears to be a few inches and not a total shutout.

That aforementioned jet energy in the US southwest will become the focal point around New Years for the next potential storm. It will actually be relatively chilly in between (Dec 29-31) with temperatures in the single numbers at night and teens and 20's during the day. Then the boat load of jet energy pushes east and should bring moisture and some sort of organized weather system. The split jet mentioned above should make some arctic cold available and it will take an adverse track of this storm to foul things up yet again. 

The general weather pattern has the same players performing the same roles for the most part. The negative -AO/NAO working for us with an irritated Pacific working somewhat against us though it will continue to feed us storm opportunities. I would reiterate how dominant the ridge over southern Greenland appears as we head toward the New Year. It dwarfs about every other jet stream feature across the entirety of the northern hemisphere and is certainly strong enough to throw a few knuckle balls our way in early 2021. New England's proximity to this weather feature would conceivably allow some relative warmth to be advected into the region from the Canadian Maritimes. I would prefer however that a storm finds a nice place to stall somewhere downstream and provide Vermont with a never ending conveyor of snowfall. For the time being though, a best guess for Vermont is that we start 2021 on the slightly milder than average side but with decent chance still of scoring some significant natural snow. 

Nightmare before Christmas looking more real, but it does look more promising as we head toward 2021

The two big things we need to accomplish during this holiday period is to get ourselves out of harms way during the potential "night before Christmas" fiasco and then see what we can stir up between December 28-30 which seems to be the next period where we could score significant snow. In the short term, we have southeastward advancing clipper system heading our way but will bring its minimal amount of moisture well south of Vermont Monday night and early Tuesday. We will see some snow flurries and snow showers late in the day Tuesday thanks to the combination of some instability and a favorable flow off Lake Champlain. I actually expect to see a few inches from this but it will be very isolated to the high country late Tuesday and early Tuesday night. Temperatures will remain

The American GFS model over the past 24 hours or so has given us a glimmer of daylight on the potential thaw/rain Christmas Eve into Christmas Day though other data continues indicate a miserable set up. The system in question is already bringing rain and snow to the Pacific Northwest but will continue to hug the Canadian border as it progresses west to east across the continent eventually ending up in southwest Ontario Wednesday evening. The system is so far north that the thawing part of the weather system will advance deep into Minnesota and the UP of Michigan Tuesday into Wednesday. As bad as that seems, if the storm can manage to spend all its money over the Dakotas and Manitoba, it will provide the opportunity for subtropical energy to fuel a new low pressure center over Dixie; and ultimately, that new storm would move to the coast, thwarting the advance of the intense mild air and even allowing rain to change to snow Christmas Day. That scenario would still bring close temperatures to 40 degree temperatures and rain to the MRV but the thaw would be shortened to a day or less with snowfall returning as mentioned. Unfortunately there are other model simulations that are considerably worse with the intensity and longevity of the thaw. These same simulations also show a disastrous heavy rain even accompanied by very strong, perhaps even damaging south winds. Really not something we want to see for many reasons and it all happens because the subtropical energy in question would get pulled due northward into the primary low actually fueling it rather than competing with it. Were this to happen, our minimal amount of snow would be easily wiped out and most of the several feet of snow in southern Vermont would be gone as well. In spite of that glimmer of hope from the GFS, I am about ready to chalk this up as another big Christmas loss. I suppose the silver lining is that most locations in northern Vermont still have a minimal buildup of snow including less than 10 inches at the Mt Mansfield stake. It will likely get wiped away by early Christmas Day but we can't lose anymore than what we have and we don't have much.

At the very least, we got some modified arctic air and snow showers that should follow for the 26h and 27th of the month. We won't have the best wind direction for terrain enhanced snows in this period but 1-2 weak jet impulses are capable of providing an occasional burst of snow. Mostly it will be cold and blustery with temperatures generally in the teens or lower 20's during the ski day. 

In spite of our problems around Christmas, we continue to have a marginally supportive pattern anchored by the -AO/NAO tag team. The irritated Pacific jet stream will limit the southward advance of arctic air,  but will set the stage for continued storminess and it certainly appears that the next opportunity for such a storm would occur sometime between December 28th and 30th. Though still more than a week out, the setup does appear to be a colder one. It also likely won't be the last one in this holiday period with another lined up right around the time of New Years Day 2021. 

The rest of 2020 looks mostly below freezing except for 1-2 days, but those 1-2 days are concerning

 A narrow area of south/central Vermont are coming off a snow event for the ages. The corridor stretching from Pawlet, VT eastward through Ludlow and Ascutney saw 30-plus inches of snow and in some instances upwards of 40 inches. The two things that strike me in the aftermath of this storm was of course the late northward shift in the forecast for one. Areas that saw the deepest snow had cloudy with a slight chance of snow in the forecast 3 days prior. In some forecasts, there wasn't even that ! I've seen it happen often enough to discuss those possibilities in the blog but its very difficult to keep throwing cold water at data when it says reiterates the same conclusion. Secondly, and this has been discussed within the weather community, is the ability of high resolution more mesoscale models to pinpoint the existence of the pivoting snow band that deposited all that snow in the aforementioned corridor. It's actually been a thing for a few years but these same models often have a difficult time with the exact placement of these bands. As it turned out, the Vermont/Mass border was too far south missed out on the heaviest totals that our friends at Okemo saw Thursday. 

The bluebird day we saw on Friday will be replaced by a few more clouds Saturday and a lot more clouds Sunday. Temperatures will close to zero degrees Saturday morning but will rebound to a seasonable 30 degrees during the afternoon. Those clouds on Sunday are still expected to produce a bit of light snow but the area of moisture associated with this disturbance appears weak and disorganized and accumulations will be confined to less than 2 inches and occur late in the day or the evening. 

We've managed to greatly reduce the risk for above freezing temperatures for the remainder of 2020 for all but one 1-2 day period. Christmas Eve into early Christmas Day and I'll reluctantly get to that in a bit. Ahead of that we have a potent looking clipper-type weather system that will attempt to merge with a stronger than expected and active southern branch storm. The latter is presenting a bit of a problem. The southern branch of the stream, typically a bit more benign, during a La Nina has been active and very existent and will send moisture and a strengthening area of low pressure to the Carolina coast Monday. This strengthening storm will try and devour the advancing clipper and take all of the moisture offshore by Tuesday. There are a few different ways this can play out but I am concerned about the scenario that keeps all of the snowfall well east of Vermont on Tuesday. The forecast continues to evolve in this time frame however so stay tuned. 

I certainly hope the outlook for Christmas Eve continues to evolve. It really looked like we had weakened and shortened a potential Christmas thaw this year and we yet might do that. For now though, we have an over-amplified jet stream during the middle of next week and a troubling sub-tropical feed of moisture out in front of a strong arctic boundary. The storm will mature slowly out in the western Great Lakes while entraining all of this moisture and there's a risk that interior New England gets flooded with mild air and rain late Christmas Eve into early Christmas Day if we can't change the narrative. Fortunately we still have time to do just that and I do expect some changes to this forecast over the next few days. The biggest issue is all of the sub-tropical energy which has been poorly resolved by medium range models beyond 5 days. One way out of this scenario is for the midwest storm to simply occlude and let any southern stream energy to drive this boat as the moisture approaches. 

Cold weather is expected to follow what ever happens in the above paragraph and remain in place, as mentioned through the rest of 2020. In the aggregate it looks like garden variety chill and nothing especially extreme although there will be daily variations. The continued stalemate between the negative AO/NAO and somewhat angry Pacific should keep the storm track close enough for multiple chances of snow. It was nice to get the 6 or so inches from the recent nor'easter but it still appears like mother nature is playing dodge ball with us on the snowfall. I certainly expect that to change as we continue along but my biggest concern is Christmas Eve. I want no part of Santa Claus and 50-degree rain.

3-6 inches in the MRV by midday Thursday, over a foot in southern VT and the outlook for the Xmas holiday looks mostly wintry !

No shutout in the MRV ! This storm won't give us what we needed but it will give us something. That something, about 3-6 inches of cold smoke, will begin just after midnight Thursday and persist through the midday hours Thursday. As you've likely heard, accumulations across the state of Vermont will vary greatly based on location. The Champlain Valley will likely struggle to get an inch but Bennington and Windsor Counties are now positioned to get a chunk of the heavy snow from this impressive nor'easter with over a foot likely in the ski area such as Mt Snow and Stratton. Heavy snow and high winds will make blizzard conditions possible in these same areas with the sweet spot for snow setting up in a corridor from northeastern Pennsylvania through the Catskills to the Berkshires. 

We've also got the cold arctic air in place which aside from producing a powdery snow early Thursday, will keep temperatures well in sub-freezing territory through at least early Sunday. The sun should make a return for most of Friday allowing temperatures to rebound into the 20's after starting near zero. We expect a repeat of that on Saturday but with less wind (Friday should feature a modest 10-20 mph wind). 

A series of innocuous looking jet disturbances will bring the next chances for snowfall to northern Vermont between Sunday and Tuesday.  Potential Sunday snow comes from what appears to be a very disorganized area of moisture but it is associated with a milder push of temperatures and this has a tendency to produce snowfall for us historically. Vermont actually appears capable of fending off most of the incoming mild air in the days ahead of Christmas and another benefit of this will be the chance for more light snow Monday or Tuesday. This system is another of the polar pacific variety and will be short on moisture but a little more potent than Sunday's system and certainly capable of delivering a few inches. 

A mild push of temperatures remains a concern around the time of Christmas Eve. In recent days the milder air has looked both weaker and less capable persisting beyond a day at most. That said, there is a chance we see a little rain in this period before much colder weather overtakes the region for Christmas Day and the weekend that follows. We've been trending in the right direction during this forecast period so I still it's possible we can remove any mini thaw/rain from the outlook but it remains a risk for now. 

Ensembles have been showing signs that the angry Pacific jet will get pacified (pun intended) around the New Year allowing for the possibility that we start 2021 on the colder side of average. We have quite a bit of time until then however and we will need our negative AO to keep working on our behalf in the meantime. The -AO has had a bit of an impressive run and is expected to include high latitude block on the eastern hemisphere side of the arctic circle. I expect this to help keep arctic cold firmly entrenched across western, central and at times eastern Canada. For us, this leaves some uncertainty as to whether we can stay on the cold side through the rest of 2020 or do we get another brief mild interlude. The cold weather beginning Christmas Day should persist through about 12/28 but this is followed potentially by another milder push of temperatures around the 29th/30th . The term "mild" has the very negative connotation for us skiers but in the mid-winter period, a weak mild push might be the catalyst for a significant snow and thus the uncertainty. I don't think this is a terrible looking pattern though for the rest of December including the holidays. Aside from the brief thaw on Christmas Eve that might not even happen, temperatures look mostly below freezing with several chances for at least light snow.  Keep the faith !

Wednesday/Thursday nor'easter appears too far south for a N VT hit but outlook looks colder through Xmas and beyond !

 Northern Vermont has gotten off to a slow start on snowfall for the season and as of December 14th, there is way too much bare ground even across the high country. With cold weather settling in across interior New England, the search is on for snowfall and if the big nor'easter confines its impact to coastal New England on Wednesday and Thursday, it will be a difficult pill to swallow. There's still a little time (maybe another upper air cycle of model data) for a late inning northward turn but clearly we are running out of outs and the odds are getting pretty steep.  As of midday Monday, the debate is revolving around when and where the strengthening winter storm will take a slight right turn off shore. The disagreement relates to about 100 miles worth of space and this leaves northern Vermont out of the possibility spectrum when it comes to heavy snowfall. There is a popular high resolution model that brings the storm far enough north for a 7-14 inch snowfall early Thursday but this same model is considerably more reliable when it comes to finer details inside of 36 hours and is unreliable when it comes to general details almost 72 hours out. That said, any storm of this magnitude is worth our attention.

 The jet impulse marking the arrival of our first serious outbreak of arctic air should bring 1-3 inches of snow to the high country around the MRV Monday night into very early Tuesday. Dry and more stable air will ultimately win out for most of Tuesday but even with sunshine, temperatures should stay into the teens during the day and drop below zero Wednesday morning. The same, dry, cold airmass is expected to maintain control of the weather across northern New England even if high clouds impact grey-out the sunshine. There's a 30 percent chance for a an inch or two of snow from the aforementioned storm and a less than 20 percent chance of something bigger that would involve a big northward shift in the expected storm track. Southern Vermont has a 60 percent chance of seeing a 1-4 inch snow but even there, the dry air will be a formidable obstacle to the incoming moisture based on what data is showing. 

Even with another whiff, the outlook for the remainder of December has good news...it's colder !! Although the jet stream in the Pacific is angry with the EPO index remaining positive, it is not indicated to be that positive. Additionally, the -AO/NAO combination is indicated to hold, likely for the remainder of 2020. I can't emphasize enough how this contrasts with what we saw for most of 2019-20. Not only was the AO positive, it was often very positive with the index actually moving off the chart on at least one occasion. We are also moving into the part of the season where competing indices are actually a good thing for snowfall in northern Vermont. I can feel the cynical responses even as I write this, but in a general sense, the holiday outlook doesn't look half bad as of today. 

Details remain a more fluid situation but appear as follows.  Dry, cold weather will continue to prevail through early in the upcoming weekend but some light snow is possible as early as Sunday and extending into the winter solstice Monday. There are hints of a more significant snowfall on Tuesday the 22nd but all of the potential snowfall (between Sunday and Tuesday) stems from polar pacific jet energy that will have limited access to GOM or Atlantic Ocean moisture thus somewhat limiting the big storm potential. Ensembles continue to show the possibility of a push of milder temperatures just prior to Christmas but this looks weaker and might not impact northern New England at all. Christmas and the days that follow all look colder and some accumulating snow is possible. The outlook today actually paints a picture that includes sub-freezing temperatures at least 90 percent of the time through the rest of 2020. That's a pretty good way to start any forecast and if we can lock that part in, natural snow will have a hard time continuously avoiding us.

We need to pull the big midweek nor'easter northward if northern VT is to get in on the action !

Some cold rain on Saturday and mild weather Sunday is not an especially exciting winter weekend in northern Vermont but the outlook going forward does have plenty of winter weather to speculate on. Incoming arctic cold is a certainty for the upcoming week but the snow is not. We managed to whiff on the weekend storm which tracked along the St Lawrence Valley and we are hoping not to whiff on the upcoming midweek event which is causing quite a stir in the weather forecasting universe because of its potential to deposit a foot or more of snow on portions of the I95 corridor. 

There are actually multiple weather systems that are of concern to the east coast over the next 5 days. The first on Monday will assuredly have no impact on Vermont passing over the Carolina and Virginia piedmonts and bringing a cold rain and some snow across the Mid Atlantic and extreme southern New England. The southward advancing polar jet stream is the primary culprit for suppressing this initial storm but the passage of the arctic boundary Monday night will bring flurries and snow showers, especially over the high country. We have a good wind direction for a few hours early Tuesday and a very unfrozen and mild Lake Champlain which should allow for some accumulation (1-4") early in the day before the dry air wins out. 

It is a very cold high pressure center (at least for the time of year) building over Vermont on Tuesday and this will keep temperatures in the teens throughout the day and allow readings to fall below zero for the first time this season Tuesday night into early Wednesday. This same area of arctic cold will wedge itself east of the Appalachian Mountains in advance of a gathering storm, giving the weather map the classic cold weather damming setup that a weather enthusiast such as myself salivates over. All the important players are there and most are positioned where they need to be for a big east coast snow event Wednesday into Thursday. The problem for Vermont is getting the storm and its moisture far enough north and models suggest this won't be easy. 

5 days ago, models were completely chaotic regarding the details for the upcoming week but they've manged to exhibit some rather impressive consistency the last few days regarding the potential midweek nor'easter. Unfortunately, that consistency doesn't involve northern Vermont getting much; instead, all the fun is along the coast. Before one chalks it up as another whiff, let me remind readers that the top 3 storms this century were all shown to be well south of Vermont within 3 days of the event. I will never forget the partly sunny forecasts in early March 2001 and much of ski country got over 50 inches of that partly sunny over the course of several days. The Valentines Day storm of 2007 and Ides of March storm of 2017 also made late northward turns and defying expectations 3-4 days out. It happens and there are reasons that it happens so although I'll call it unlikely, it's hardly impossible. 

I'll briefly discuss the outlook beyond the middle of the week and extending through the Christmas holiday and expand on this in a subsequent update. The fundamentals look about the same. We are battling the angry jet in the Pacific, but are getting some help from the -AO/NAO. I expect we will be discussing a potential event during the weekend of the 19th and 20th (next weekend). We will have lost a chunk of the upcoming week's cold weather by then but not all of it and thus have a chance of procuring a bit of the good stuff. Ensembles are then suggesting a roller coaster with seasonable temperatures around December 22 potentially giving way to a mild surge around Christmas Eve. This would be then followed by colder weather on Christmas Day and the few days that follow. It's not an ideal looking weather pattern around the holiday but I've seen worse. Let's see how we look in a few days

Colder outlook next 10 days and a possible big east coast storm for the middle of next week

We've got a colder trending upcoming next 10 days and we've made the weekend forecast a close call but have yet to complete the comeback as of later Thursday. What we can do in this update is guarantee a wintry next week. The stars aren't totally aligned for a massive widespread outbreak of cold across the United States but the combination of the block over the Chukchi Sea and the strengthening -AO/NAO combination is going to bring some intense cold to New England early next week, the first such occurrence of the season.

A relatively mild day is still expected Friday and the slightly above freezing afternoon temperatures are expected to persist through Friday night into early Saturday. At the same time arctic air will be building across eastern Canada and will try and make a slight southward into Vermont during the day Saturday. Though this push of cold should be effective enough to put northern Vermont back on the cold side of the temperature boundary, it does not seem to be enough to bring us snow. Far northern Vermont is likely to see some ice and the MRV appears targeted for a cold period of light rain. We aren't far from the snow however. Montreal should see a sizable amount from this event leaving us less than a 100 miles south of where we need to be. This is a lot of ground to make up in a few days but not impossible. 

Low pressure associated with this precipitation will slide east of us by midday Sunday and any drizzle or light rain is likely to end as some snow flurries. For the most however, the weekend will end on the dry and mild side with temperatures remaining above freezing throughout the day before returning to sub-freezing levels late in the evening. 

Now on to the good stuff. The outlook for next week has gained a bit of clarity and although snowfall remains uncertain, we know it will get pretty cold. That arctic air I've been talking about in Canada will take a swing at us as a polar vortex gets vertically stretched late this weekend into Monday. We stay dry and mostly seasonable Monday and then a few snow showers mark the incoming arctic chill Monday night. By early Tuesday, readings could be close to zero and might struggle to reach the teens during the afternoon in spite of what forecasts on your device are telling you now. The cold is what we know however, the snow is what we don't. We've got a solid amount of data indicating a storm advancing from the plains to the lower Mississippi Valley by early Wednesday and a beautiful looking cold air damming signature along the east coast in advance of this strengthening storm. Man, it feels like forever since the east coast has been blessed with a decent cold air damming event, I almost forgot it can happen ! 

All of this is good for east coast snow but what about Vermont snow ? Data on Thursday showed a better event farther south but by no means is this a done deal. We are positioned well for a shift and model data always, always shifts on any event 6 days out. As for the cold air, we should see our coldest temperatures Tuesday night into early Wednesday, the possible snow Wednesday into Thursday followed by sub-freezing but not quite as extreme temperatures to finish the week. 

The longer range looks similar today with the same competing forces battling it out for control of the weather pattern. At face value, ensembles do show a slightly mild signature in the aggregate in the week leading up to Christmas but not strongly so. There are also indications of another weather event around the time frame of December 20/21. Other than that its a slightly angry Pacific and a negative AO/NAO duking it out.

Indications of some colder ingredients this weekend/early next week but we are not out of harms way

 Lake Champlain delivered an inch or two of surprise snow to the high country surrounding the MRV Tuesday. All it takes this time of year is the right wind direction (northwest) and just a minimal amount of low level instability and the magic happens. We expect some additional snowfall on both Wednesday and Thursday. It won't be much but its something and it comes thanks to a weak jet stream impulse riding along a temperature boundary. A corridor of moisture should establish itself from the Adirondacks to the Green Mountains by late morning Wednesday and although the best moisture and snowfall appears confined to the Adirondacks, light snow is likely to bring another small accumulation to the MRV by evening (1-2 inches). This snow is likely to continue and become flurries and snow showers Thursday though temperatures are likely to climb to above freezing levels in low lying areas even as another 1-2 inches is received across the high country. Not a bad 3-day stretch but a rather mild day Friday is likely to eliminate decent percentage of our midweek fluff, whatever falls.

 Beyond Friday the forecast has become more challenging but in the aggregate has improved just a small amount. A tight jet stream in the Pacific will have an adverse impact on the weather pattern, providing an invariable headwind that is likely going to continue through the winter solstice.The pattern is not "unblocked" at high latitudes however; in fact, a rather significant block is expected to form over the northeast Russia and migrate over the Chukchi Sea just northwest of Alaska. This combined with a broad area of ridging in Scandinavia and Greenland is expected to flood northern North America with arctic air. Yes, much of it will be centered in northwest Canada but some will migrate eastward as well and cross the mostly frozen Hudson Bay (it has become mostly frozen early this year). It's all so La Nina but it also means arctic cold will become a more capable ally during any weather situation beginning this weekend. It still looks rather mild late Friday into early Saturday but the approaching storm no longer appears to be a spent force in the Midwest and will approach with a bit more cold air to work with. We still might see a bit of ice and rain but base building snow in northern New England is now within our grasp. Were it to happen, it would happen late Saturday into early Sunday. Models are all over the play and I expect they converge on a solution in the next day or two.

Precipitation late Saturday or early Sunday could be the start of a few days featuring unsettled weather. Models are hinting at multiple waves of activity with a second wave of precipitation possible around Monday. One area of cold air will be retreating northeastward into Canada at this time while a new area of cold will be arriving behind this second wave. The details are just impossible to sort out right now and are so likely to change that any attempt to pin this forecast down is pointless right now. That said, the period between Saturday to early Monday does appear a bit colder in northern New England and capable of potentially supporting some snowfall yet still incapable of allowing for a big event or eliminating all the rain/ice from the outlook. 

Next week's weather isn't likely to end with Monday either.  A La Nina pattern in a La Nina winter appears set to send wave after wave in our direction with another one producing another possible storm during the middle or end of next week. This storm has the best chance of being an all snow-producer across interior New England but such an outcome is hardly a guarantee. Models are having enough problems with the next 5 days making the weather beyond a week especially blurry.

The longer range ensembles continue to paint a similar picture as we approach the Christmas holiday. The jet stream in the Pacific appears angry while cold air is positioned close by in Canada thanks to a negative AO/NAO combo. It will be active and we need to place ourselves on the right side of the action or it will be more rain and ice. Two things that will help moving forward are this. 1) Moving deeper into the heart of the cold season moves the expected storm track southward simply because of climatology. 2) 44 N latitude is a good spot. We won't miss too many storms the rest of this month because we are too far north. Instead, we are likely to see several events where latitude is helpful.

Next 10 days has some limited potential for new snow but includes a liklihood for rain/ice for weekend of 12/13th

 The storm this past weekend turned into a big tease, tracking too far off shore and failing to deliver for most of Vermont, depositing snow in New Hampshire and Maine instead. It all is part of a rather inauspicious start to the winter season which has been dominated by mild air in November and a big miss to start December. Though the weather pattern for the next 10 days has some limited potential, models are only limited amounts of snowfall right now and we have not eliminated the rain/ice risk.

Though arctic air is in very limited supply across North America right now, the jet stream is carving out a deep enough trough to sustain several days of sub-freezing temperatures (through Wednesday). Aside from flurries and an occasional snow shower, snowfall will be limited thanks largely to a strengthening storm off the eastern seaboard which has the effect of robbing us of our moisture. That said, a weak but fast moving jet stream impulse marking the approach of milder air should bring some limited snowfall to the northern Green Mountains late Wednesday. Temperatures Thursday are expected to eclipse the freezing mark across low lying areas but the risk for snow showers remains Thursday over the high country. I can't promise too much from all of this but a few inches is possible with the best chance for 6 inches from Stowe northward to Jay Peak. 

Following a dry day Friday, we can expect another more significant storm to impact us this weekend. I can't say I am too delighted with the picture the models are painting as of Sunday. We still lack a supply of arctic cold and the approaching storm in the Plains appears intent on maturing rapidly over the Mississippi Valley and ultimately occluding well before reaching the eastern seaboard. Unless much of this storm's energy transitions to the coast, we are looking at an ice/rain type situation on Saturday with little hope for any snowfall. 

As promised, arctic air will become more prominent over Canada beginning this weekend as a broad area of ridging in the jet stream stretching from Scandinavia to Greenland will allow colder air to bleed southward in North America. As this is happening however, the ridging in western North America will break down while the jet stream in the Pacific strengthens. Much of eastern North America will thus be dealing with conflicting teleconnections indices with the -AO/NAO favorable but the +EPO/-PNA more unfavorable. We can still expect some cold weather accompanied by snow showers Sunday into Monday and that cold weather should be the strongest of the season so far (not saying much) and remain entrenched into the middle of the week. At that point, another storm system will be approaching and it will mark another opportunity to take a step forward on the season. 

Beyond the middle of next week, we will continue to have some limited support from the Arctic Oscillation which is a big improvement relative to last year when we had basically none after the middle of December. Still, the jet stream in the Pacific and in western North America appears a little problematic. We can often survive the former so long as the EPO doesn't get too positive but a lot of jet energy and cold will become focused on western North America by late next week and will become one of the more glaring jet stream features on the globe. Though it doesn't automatically point toward a sustained torch (especially with the competition from the AO) it will make the storm track potentially difficult. It also looks very much like a weather pattern one might see during a La Nina. 

Northern Green's now sit on very western edge of accumulating snow for weekend storm

As promised, we should be able to provide a more definitive outlook regarding the storm this weekend. There has been quite a bit of noise regarding the upcoming weather situation and a lot of it seems to stem from a more recent phenomenon on twitter which involves selectively posting maps of models showing the snowiest of all scenarios.  The big reason I punted on an update yesterday was that models failed to provide anything truly conclusive in terms of a storm track and there never was a consensus for a 2-3 foot powder producing bonanza though twitter might have you believe that there was. Operational model data can inherently be statistically noisy and that noise is amplified when a 100 mile difference in the track of a storm changes the total snowfall by upwards of 2 feet. 

As of early afternoon Thursday, the data has finally converged on the idea of a big storm this weekend tracking close to the Cape and Islands. This storm, originating as an unusually strong southern streamer (given the La Nina) will indeed phase with northern stream kicker and deepen dramatically as many storms do upon interacting with the natural baroclincity of the eastern seaboard. The data today is in much closer agreement that the track of this storm stays mostly offshore. This is good for ensuring all snow but bad for total precipitation amounts and will thus keep a ceiling on total snowfall amounts for all of the Green Mountains. Much as I wished it not so, this was a trend I feared would continue Wednesday and we now sit on the western edge of the conveyor of decent snowfall with the good news being that the Vermont high country is one of the few locations that should see a powdery consistency to any snow. 

Only a minimal amount of cold air to work with during this event and following a relatively mild day Friday, temperatures are likely to climb into the lower or middle 30's in Vermont as snow begins during the early afternoon. As the storm continues to deepen near Cape Cod, temperatures will drop off into the 20s, especially across the high country but total snowfall will depend on whether we can pull this storm into Cape Cod Bay (even just a little). Should we be able to do this, our storm total could exceed 6 inches but should we not than it's a 2-6 inch wind-blown event with flurries and snow showers continuing into early Sunday. This is still an impressive storm and appears to be another knuckleball type situation for forecasters meaning another sudden change would not surprise me. 

The onset of the snow Saturday should also begin a healthy stretch of early December sub-freezing temperatures. Nothing especially noteworthy but readings should drop into the teens Sunday, Monday and Tuesday nights across the high country and generally stay sub-30 during the subsequent days. Our next chance for precipitation comes thanks to a milder push of temperatures during the middle of the week. It is a little uncertain how far northeastward this mild air, originating in the plains can push, but I am looking at some newer data suggesting it will not quite reach Vermont (at least not next week). One and maybe two impulses riding along this temperature boundary will bring the potential for some snow to ski country with the first arriving Wednesday and second prior to the weekend of December 12th/13th. 

Following what looks to be a rather tame weekend (December 12th/13th), we should see a bit more arctic air enter the forecast picture. The major ensembles are starting to show a weather system that may or may not get hung up across the southwestern U.S. after December 14th and this would certainly have an impact on the southward push of any arctic cold. Consistent with the last update however, Canada is expected to be a lot colder thanks to a broad area of ridging in Scandinavia and a slightly negative Arctic Oscillation. I I think this should ensure a period of below normal temperatures between the 15th and 17th of the month. The Pacific Ocean has shown a reluctance to cooperate however and I am skeptical and even doubtful that the stretch of cold 2 weeks out is the beginning of a more sustained period of below normal temperatures. Still, its not a bad two weeks but it would be a lot better were we to squeeze a decent event out of this weekend and we appear to be right on the edge. 

Onward and upward from here with temperatures slowly expected to chill and a possible storm this weekend

December arrives with temperatures well into the 50's across the MRV while temperatures in Tampa, FL were 49. This would illustrate the power of a phased and very strong storm system that tracked up through western New York. This recent storm would be a snow-eating abomination given the combined efforts of strong winds, high dewpoint temperatures, rain and even thunderstorms in many areas. There was little snow to lose across the state however and we continue to exist as we did in late November, albeit a little muddier and with higher river and creek levels. December mud is a little depressing for sure, but we got a few things going for us over the next two weeks and we should be headed in a positive direction on the snow front shortly and if we are lucky maybe we can hit one out of the park. 

Lingering instability from our recent storm will drift north-northeastward over the next two days through western Quebec up in Canada. Temperatures will eventually become cold enough to support snow flurries and snow showers across Vermont, especially the high country. That said, winds will never align properly for any significant accumulation and the best instability is well to our north. The high country will likely get a bit white but that's about it from what was a rather putrid storm on the whole for Vermont. Temperatures will also continue to remain on the mild side through Friday, just not as excessively so. High temperatures will continue to climb into the 40's in low lying areas with below freezing temperatures at night. 

Our eyes remain fixed on a second substantial southern streamer that we expect to be loosely positioned over Alabama/Mississippi on Friday. We still expect this storm to make a northward turn but models have been delivering varying results on whether not this storm is the 2nd to phase and become a massive precipitation producer for the east coast this weekend. The consensus suggests that indeed it will. Consensus also suggests that the track of this system will be much farther east and in fact mostly off shore putting the high country of Vermont in play for a bit of snow. Arctic cold or even any kind of cold is so sparse over lower North America and this will continue to present a challenge for those hoping for big snow, especially over low lying or coastal areas of the northeast. MRG is away from the coast obviously and a bit higher up giving us a shot at a decent accumulation of elevation sensitive snow given the track and evolution. 

Essentially we have a benign Canadian clipper system that will dive southeast Friday and attempt to phase with the aforementioned southern branch energy. I don't want to get too bogged down with the various scenarios except to say there's still a better chance something happens than it doesn't (Like 60/40). Even if the storm gets washed out to sea, the pattern will remain pretty dynamic albeit non-arctic. After a mild day Friday, we have a chance for some light snow Friday night, followed by the possible impact of said storm between Saturday and Monday. Even a big swing and a miss does not eliminate the chance for small amounts of snow showers/flurries from 1-2 different polar pacific impulses in this same time frame. Additionally, the pattern remains supportive enough for an additional chance snow later in the week. 

Regarding the uniqueness of this La Nina, non-arctic, but stormy pattern, the various ensembles suggest different evolutions, none of which are especially unfavorable. There are indications of a weaker push of milder temperatures around the time frame of December 12th and 13th. As this is happening however, both major ensemble packages indicate that a broad area of jet stream ridging across Scandinavia should help to flood much of Canada with Arctic air. The American Ensembles maintain that signal of a positive PNA structure and allowing that arctic air to be more of a force across the United States. The European less so but even this evolution would depict a pretty wintry Vermont in the period beginning December 13th to 17th. 

Needless to say, I am encouraged. It's wet and bare and pretty ugly out there but it won't be for too much longer. 

Incoming stormy pattern to deliver a rain event first and a chance for more interesting outcomes thereafter

 I was hearing a lot of noise a few weeks ago that eastern North America was lined up for a torch in December. To be perfectly fair, climate models were indicating a warm month and there are those that put a lot of credence in the European model weekly forecasts and those were spitting out some very mild temperatures as well. The exceptionally warm November we are experiencing certainly doesn't seem encouraging either and a more persistence based forecast would argue that things that are happening will continue to happen. I am actually a fan of giving some weight to persistence based predictions but I don't put much stake in the climate models or the European weekly forecasts so it does not surprise me that we appear headed toward a rather interesting and very stormy few weeks and a period that is NOT expected to stay exceptionally mild. One thing for sure, it does not bear a resemblance to a typical La Nina winter weather pattern. There's split flow, phasing storms and cool weather in the south. Although La Nina doesn't make those occurrences impossible, they are infrequent. 

Unfortunately Vermont does not appear to be in the best position to hit this La Nina knuckle ball but it will be exciting nonetheless and we should be in a much better place 2 weeks from now throughout the state. November will end mild but only because we end up on the mild side of a powerful and fully phased winter storm - a southern streamer that will take in a polar pacific impulse and explode over the northern Appalachian Mountains Monday. The explosive intensification results in the bowling ball - looking upper air environment and in this case it means the mild air and rain comes our way with the cold and snow impacting the Ohio Valley and Great Lakes. There is no escaping this and it might as well happen now with little to no snow on the ground. Rain will arrive late on Monday and continue through the evening before tapering to the more intermittent stuff by Tuesday. Your smart phone might be telling you rain on Tuesday but most of the day will actually be rain-free with temperatures hovering around 50. All this happens while the snow piles up over portions of the eastern Great Lakes.  There isn't really any arctic air with this storm but it will get colder by Wednesday and we should see mixed precipitation become snow. Again, just intermittent stuff but by Thursday morning, the high country is likely to be white. 

The pattern won't stop delivering after the Monday/Tuesday event. There are strong indications of a 2nd storm next weekend (December 5-6) and although we would certainly like to see more cold air support, there are indications of a bit more help from a storm track that is likely to set up farther east. Storm impact remains 8-9 days out which means inherent uncertainty and it would be unwise to expect a powdery bonanza without the help of much arctic air. This one is worth watching however so stay tuned. 

There are a lot of neutralizing teleconnection indices that are allowing the pattern to become the stormy madness. The Pacific is a little strengthier than I would like but not terrible. AO/NAO will remain relatively neutral while the PNA turns varying degrees of favorable depending on what model you believe. Though arctic cold is not expected to be a part of the equation during the first 6 or so days of December, we should see some enter the weather picture as we approach the time frame of December 10th. If we keep a bit of this storminess alive, and there are indications that we will, we could reach the middle of the month in decent shape.

La Nina spreading some big wings as winter 2020-2021 approaches !!

Though it may not feel like it, we’ve managed to reach late November and the commencement of another ski season. When the SCWB signed off late last year, the worsening pandemic felt like a big black hole enveloping us with no way out. As of November, the black hole still envelops us, but to borrow (and slightly alter) one of Carl Sagan’s most famous quotes, “Us Vermonters have a certain talent for adaptability” and we will apply that adaptability to piece together a ski season while dealing with and overcoming the many obstacles.  As I see it, the weather is presenting a few obstacles as well, but its nothing we aren't used to. For those of you that will never get used to the wordy discussion, please skip ahead to the bottom and receive the less than wordy outlook !

The three months leading us into November were exceptionally normal in terms of temperature, landing .  within a half a degree of normal. There was some concern early in the summer of a worsening drought but a succession of very wet months (August/September/October) has alleviated many of those concerns. The current US drought monitor still puts us in a D1 area - Drought Monitor, but the overall water situation has improved since some very dry months in the spring and early summer. Within the vicinity of the North American continent the two most glaring aspects of weather was the persistent heat and resulting forest fires in California and the remarkable hurricane season which culminated in two historic landfalling storms (Eta, Iota) very late in the tropical season. Many will refer to the 2020 tropical season as record breaking because we blew through the alphabet and well into the greek letters. This is a little deceiving since the technology is available to better indentify weather systems that meet the various thresholds to earn an official tropical name. To see a category 5 storm strike Central America in November is nothing short of remarkable however and truly cements 2020 as a historic one for tropical activity. 

What about this La Nina 

The tropical cyclone activity in 2020, particularly the strength and unusual late presence of that activity deserves a place in the discussion about climate change (and it will certainly get one). That said, a strong and active hurricane season is pretty typical given the presence of La Nina and we’ve had a notable one since late in the summer. La Nina’s are best illustrated by a line of anomalously cold water in the equatorial regions of the Pacific and aside from the aforementioned impact on the hurricane season, can, when strong enough, have a material impact on winter weather across mid-latitude North America. So what are we looking at this year ? La Nina was gradually strengthening, reaching a value, based on a temperature anomaly of  -1.7 C in late October though it has recently subsided a touch since then. Anything under -1 is significant and were it to stay there through the winter will most assuredly have something to say about our prevailing weather pattern.  So what is that weather pattern typically ? A more concentrated storm track in the Pacific, generally north of California (they could certainly use more rain), cold weather confined to the northern tier of the US, warm, dry weather across the southeast U.S. and active weather in the northeast. Active, because usually the storm track takes dead aim at New England and can bring varying results. 

 

  (Above are some of the bigger La Nina's going back 70 or so years, some weaker but notable La Nina events not included)

I am not a fan of strong ENSO events of any kind (La Nina or El Nino) as they bring with them many risks and are infamous for inconsistency. The 70 years of data does present a rosier picture however with several weaker La Nina's yielding huge snow years and a few stronger La Nina's delivering the same. Every inch of latitude-north is important and locations south of 40 N often perform quite poorly. The results really vary across Vermont as illustrated by both attached figures and results are highly dependent on what side of Vermont does the prevailing storm track establish itself. Is this a forecaster speaking from both sides of his mouth ? Absolutely ! but the information is revealing and it makes sense. A storm track aimed at Vermont as opposed to well south of Vermont is actually a positive thing, it just doesn’t always produce positive results. In colder La Nina years, and there are several like 1970-71, 1995-96 (weak La Nina), 2000-2001 (weak La Nina), 2007-2008 and 2010-11, the results are fantastic. This is year 17 of the blog and I rank 2007-08 and 2010-11 as #1 and #2 respectively for MRG ski years and both had significant La Nina’s. Unfortunately 1988-89, 2005-2006 (weak) and 2011-2012 (weak) also featured substantial La Nina’s and were awful snow years. Either way, La Nina’s can produce up and down results not only from one season to another but within that season. It is rare to go more than a few weeks without some classic Vermont-style rain/ice catastrophe. 

 

 (This illustration is pretty worthless to the naked eye except it shows the snowstake at Mt Mansfield which is never worthless and also shows the wide variation in results during La Nina winters)

PDO/Pacific SST

So how can one determine whether we get the good or bad version of La Nina this upcoming winter. It naturally leads us into the Pacific Decadal Oscillation (PDO) part of the discussion which includes a broader overview of sea surface temperature patterns in the Pacific Ocean. The PDO phase is determined by sea surface temperature configurations in the mid latitude Pacific. When cold SST anomalies hug the western North American coastline it illustrates a negative phase with the reverse indicating a positive phase.  A positive PDO phase does correlate well to a more favorable weather pattern for east coast cold and snow but they are rare during significant La Nina winters. Officially however, we remain on the positive side of neutral going into the upcoming winter. I want to convince myself that this is a uniquely positive indicator but the data going back 70 years is inconclusive at best. Several of the snowiest winters in Vermont on this decorated list occurred with both significant  La Nina’s and very negative PDO phases. What is a forecaster to do aside from ramble on and on ! 

Autumn 2019

 

 

Autumn 2020

 

 

 

With each year of blogging and seasonal forecasting, I continue to be a fan of PDO assessments. The winters of 2014-2015 in particular was dominated by very large, sometimes record breaking positive PDO phase underscoring the predictive value of this variable in a seasonal forecast. I’ve also realized however that the nature of the PDO is also of great importance and this speaks specifically to a deeper look at sea surface temperatures in the mid-latitude Pacific Ocean. Last year, the persistent Pacific Ocean warmth stretching from the Aleutian Islands through the Gulf of Alaska left us with an invariably strong Pacific Jet and had us fending off mild air a lot more often than we would prefer. Unfortunately, much of this SST configuration remains and the blob of warmth appears especially formidable south of the Gulf of Alaska. The only difference this year would be that the aforementioned warmth does not extend all the way north into the Gulf of Alaska. Though the map seems to indicate a more negative PDO index, it remains barely positive for now on the basis of some of that warm ocean water extending all the way to the North American west coast. The continued presence of the mid-latitude Pacific warm water is the most concerning variable right now and it underscores the importance of taking that deeper dive into the PDO/Pacific SST assessment. The weather pattern seems intent on dumping a lot of colder air into that region of the Pacific over the next 14 days and it will be interesting to see if that can weaken the area of anomalous SST warmth.  

Snow Cover Expansion

We recorded another strong snow build across the northern hemisphere in November. The 21.22 millions of square kilometers observed in 2020 was the 9^th consecutive October where the land area of snow cover exceeded 20 millions of sq km. Prior to this 9-year run of strong October snow expansion, the average extent of snow cover was about 18 millions of sq km with a standard deviation of roughly 2.5. Relative to that average, all but two of the recent 9 years have been more than a standard deviation above average. To borrow the phrase from former NBA star Rasheed Wallace, “Ball Don’t Lie !“ and neither do these statistics. Either the prior  almost 50 years of data are wrong or more likely, the expansion of snow and ice in October is a byproduct of other trends and changes occurring very quickly at arctic latitudes. The obvious player here is the alarming loss of sea ice as a result of climate change which results in more open water across the Arctic Ocean during autumn and an altered snow climate across northern latitudes. I’ve had to consult with others to verify this hypothesis and I am relatively convinced this is the cause. Without getting too immersed in the weeds, this conclusion changes the way one would use this data and would indicate that the old “normal” doesn’t apply. 21.22 millions of square km is still a very strong number, especially since it is largely driven by the 10.26 millions of square km recorded over the North American continent. That said, this year’s data falls smack in the middle of what was recorded over the last 9 years and is behind what was recorded last year.

Meanwhile arctic sea ice which has, what we think, is a causal and inverse relationship with snow cover expansion been near or at record lows for much of October into early November. We have seen ice expand into the Hudson Bay in the past week or two which conforms to climatological expectations, but as a whole, sea ice continues its longer term decline and that decline is more than alarming when looking through the geological time scale lens. 

 

Atmospheric Poker Tells 

Has the atmosphere given us any poker-style “tells” this year? Some things are obviously very different this year verses last year like the emerging formidable La Nina and the many strong hurricanes. Some things are the same such as the blob of sea surface temperature warmth in the mid latitude Pacific. But how is the weather actually behaving ? We had those succession of “normal” but relatively wet months this fall and what appears to be a relatively mild November. In Vermont, the mild weather has been more garden variety but across the U.S. as a whole, it will likely go down as one of the warmest November’s on record (guessing top 5). I am particularly interested in the behavior of the Arctic Oscillation (AO) since we would all like to avoid a recurrence of 2019-2020. When aggregated over the entirety of last winter, the AO was the 2^nd highest on record and though the season wasn’t completely free of good moments, the persistence of the +AO was the elephant that thrashed the room and proved too difficult to overcome. The AO did surge early this past November, rekindling some of those bad memories but has since faded and is forecast to be close to neutral through early December. You can’t say too much from what we’ve seen so far except that we have yet to see good evidence that the weather pattern is showing a propensity to get blocked. So far it has not !! This combined with the mild turn this November and some more localized SST warmth off the eastern seaboard is a little concerning.  

 Our Winter Outlook 

The outlook is thus as follows. A mild winter can be expected on the whole, but consistent with the traditions of La Nina, there will be interludes of both very mild weather and cold and snow. What will hurt this winter, in my expectation, is the likely inability for a cold, snowier pattern to lock itself in for more than a span of 3 weeks; in fact, we may be lucky to get 3 weeks. That said, I think the winter has some things going for it. La Nina combined with a modestly positive EPO will keep the storm track pointed in our direction and even if extended periods of favorable weather aren’t expected, several broken up decent periods are likely. Additionally, we are in a much better place for snow given this set up than southern New England, the Catskills, Pennsylvania and points south. Latitude will be good and even 10 miles of Rt 100 might make a difference in certain events. I would expect the mild weather will keep snowfall below average this year but we will have our days. Again, I would be surprised to see 2015-2016 revisited. We could also surprise to the upside as several La Nina winters have done. I am shying away from a snowy La Nina forecast based on the SST configurations in the Pacific and recent behavioral pattern tendencies but it wouldn't be unprecedented or that surprising. In the end I am guessing MRG procures around 200 inches of snow.

Hope everyone has and will stay safe through the thanksgiving holiday. A special shout out to those essential folks working through the pandemic helping all of us get through this. It can't be easy and it hasn't gone unnoticed. See you all on the mountain !

Winter 2019-2020 was a long time ago. But I revisited anyway

Though we will look back at the 2020 season for too many of the wrong reasons, it still had its moments. It won’t rank as one of the better winters over the past 25 years and most certainly resides in the bottom half of that sample size. With that said, it is probably closer to the middle than the bottom and at least northern Vermont could brag about some some while other locations to the south saw hardly any. 

The above graph is from the ever-popular Mt Mansfield snow stake site. I actually prefer to take a sampling of final snowfall totals from various ski areas around the northeast (sometimes outside of the northeast) but most stopped reporting as of mid-March. “The Stake” at Mt Mansfield apparently can’t be stopped and it always proves to be an invaluable resource for weather and data enthusiasts such as myself. The color coded lines can appear a bit blurry to the eyes but the pink line is 2020 and it runs behind most years this past decade with the exception of the of 2011-2012 and the Super-Nino debauchery of 2015-2016. We were able to keep pace with 2017-2018 for a while but were unable to score another miracle March and instead recorded a rather ordinary to sub-ordinary one. The 5-week "arctic spring" is also notable. More on that below.

Choosing the one single variable that defined the personality of the past winter was easy this year. Hands down it was the Arctic Oscillation (AO). Scientists have officially been tracking that index going back to 1950 and it remains one of the best gauges we have to measure how blocked the jet stream is over high latitude regions of the Northern Hemisphere. When aggregating over a 5-month period (Nov-Mar) the AO this past winter was the 2^nd highest ever recorded. 1989-1990 remains the winner and 1990-1991 had a strong bronze medal showing but 2019-20 both intense and persistent, often challenging the confines of the graphical display while spending all but a few weeks in positive territory. Below is a chart measuring the top 5 +AO years and top 5 -AO years

When you consider those headwinds, 2019-2020 doesn’t look quite as bad. 1989-90 and 1990-91 were decidedly worse snow years based on data from the Mt Mansfield snow stake and 1992-1993 benefitted from of the greatest winter storms of all time. It also shows that Vermont can survive the adverse impacts of a +AO year a lot better than areas farther south. Winter across the Mid-Atlantic was nearly non-existent and ski areas suffered a much milder fate relative to Vermont. Atlanta, GA was nearly 4 degrees above normal over that same 5-month period. 4 degrees may not be a lot for one month but over the course of 5 months makes it one of the warmest winters on record. The same can be said with -AO winters. All 5 winters on the above chart were good snow years but the record year 2009-2010 actually featured a weather pattern that became too “blocked” and many of the best storms missed Vermont and deposited snow on the I95 corridor instead. Atlanta, GA by the way, recorded one of the coldest winters over this same period. 1968-69 was absolutely historic in Vermont and one of the best snow years ever recorded in many locations.

We also spent much of the winter talking about the persistent tightness of the jet stream in the mid-latitude Pacific Ocean. This zonal, fast to east moving consolidated jet stream mitigates the impacts of arctic air over mid-latitude North America and the index that best measures this is the Eastern Pacific Oscillation (EPO) index. The positive index which is defined by a version of this weather map is largely what we saw throughout the winter. Notice the cold over Alaska which was very prevalent through much of the past several months. 

Though the EPO was very positive through much of the winter, once I went through the rather tedious process of parsing through all the daily data I found that the positive value of around +33 was closer to zero than I would have thought. The two winters prior to this recorded values in the mean of close to -60 and the super evil empire winter of 2011-2012 recorded a value of close to +80. In other words, the EPO was an issue but the +AO, based on the aggregated data, was a bigger issue.

If I had to identify a single culprit to the persistence of the +AO/Somewhat +EPO pattern this winter it would be the configuration of sea surface temperatures in the Pacific. More specifically, the massive blob of sea surface temperature warmth that positioned itself south of the Gulf of Alaska. It was a large contributor to what became a negative Pacific Decadal Oscillation season. A negative PDO is not, in and of itself a pattern killer for snow and winter lovers in New England but the persistence of a jet stream level ridge underneath a glaring lack of blocking in the Arctic became the most prevalent adverse variable in almost every update I did this past season. Interestingly, this feature was identified in the  pre-season outlook as a concern but it was pitted against what was, at the time, a glaring lack of sea ice in the Chukchi Sea (regional body of water north of the Bering Strait). As it turned out, the Chukchi Sea quickly froze and we were left with the anomalous body of sea surface temperature warmth described above. Such a sea surface temperature setup is often associated with La Nina winters but not this time. The equatorial Pacific stayed on the Nino side of zero throughout the winter, and though we did see an energized southern branch of the jet stream at times, the weak El Nino did not greatly influence our winter season one way or another. 

November and early December saw the best stretch of pattern fundamentals and the season was off to a promising start. The high country surrounding the MRV did see several small but measurable rounds of accumulating snow and temperatures were 5-7 below normal for November which was colder than 2018. The biggest difference however was the lack of Snowvember. We were teased with the idea of big storms on a few occasions but nothing ever materialized. Thanksgiving was white but just not “deep” white. Still, the persistent cold was promising and it finally looked like the pattern would bear fruit in early December thanks to a bombing area of low pressure along the east coast. Though the storm did deliver several inches to the MRV, the heaviest snow fell across southern Vermont, the Berkshires, Albany, NY and the Catskill Mountains to the southwest. I feel like this storm was an inflection point. Had we bullseyed that sucker, and we were close, we may have remembered this winter very differently. 

Cold weather persisted in a general sense to about the winter solstice but there were two somewhat damaging thaws within the week of December 9^th to 15^th that limited our ability to establish a base. The coldest day of the season was actually December 19^th when the high temperature struggled to reach 5 but we only managed to muster a few inches of snowsqualls and had limited snowcover going into the holiday. At that point, the pattern broke down and much of what was described in the above paragraphs, a very positive AO (unblocked Arctic), a somewhat positive EPO (zonal Pacific Jet) became the prevailing influence on our weather pattern. Christmas was wintry but there were several days around Christmas that were not.

The loss of Rush drummer Neil Peart cast a dark shadow on the early part of January 2020 for me personally. Looking back, I suppose it was a lead indicator of the rough year that was to come.  On the weather side of things, the 10 days that began on around December 29 and ended around January 8^th was one of the better stretches of the season. Though the pattern wasn’t entirely supportive, a once upper Midwest blizzard deposited a mixture of snow and sleet on the MRV and provided a few days of instability leading up to New Years Day. No it wasn’t epic, but we got a bit of all of the necessary ingredients starting with a good base building storm a few a few inches of powder on the 30^th, the 31^st and on New Years Day. Temperatures crept above the freezing mark for a few days on the January 2^nd, and 3^rd but we were able to score some additional snowfall on the 4^th and procured a nice first weekend of the new decade. A few days of snow showers and squalls during the following week gave us a temporary impression that winter was resettling in. Unfortunately, this didn’t last. A very mild weekend January 11^th and 12^th and some rain put a massive dent into the base and put a crimp into the rest of the month. We got a bit of cold weather and snow in the week that followed but the big storm proved to be elusive. The best chance for one came without much cold air support on the last full weekend of the month. I remember talking about walking the proverbial “tightrope” and hoping for the perfect storm track. In the end we kinda fell off the tightrope a bit but did receive a bit of decent snow across the high country while the low elevations got a bit of wet weather. 

February was a tale of the “same story, better result”. It was historically awful for snow along the I95 corridor including all of southern New England and New York City. Boston recorded only a half inch of snow for the entire month and New York City only recorded a trace. As the AO continued to soar, nearly breaching the limits of the visual chart on two occasions, temperatures continued to run above average across much of the United States including Vermont which saw readings 3-5 above average. We did get the snow however, mainly from two different but substantial events. The first on February 6-7 was the best of the season. It was a windy event which proved to be a challenge for some resorts to manage but we got the powder, almost 2 feet of it and we got a few days of cold weather on the ensuing weekend which included a calm Sunday February 9^th. The other big event occurred toward the end of the month. It was a wetter snow event at the low elevations but an overperformer nonetheless with around a foot of snow. We had hoped to score the additional instability snow leading into the weekend but winds remained westerly as opposed to northwesterly favoring the snow over locations such as Stowe and points north. The two storms in February might have made the month a more memorable one but there was a lot of mild weather in the middle of the month. We did manage to avoid much of the rain but not all of it. 

March brought in the Covid19 pandemic so I suppose it was good year to not have our traditional mid-month snow bonanza. The first 15 days made up the last 15 days of the season for most resorts and it featured big temperature surges and occasional rainfall. It didn’t look especially good for a wintry finish to the season but it goes to show that you just never know. I am saying this completely in jest but it is almost as if the pattern waited or Governor Phil Scott to issue his stay at home order and suddenly everything fell into line. The positive AO became completely neutralized and a “well blocked” jet stream emerged. It showed up in the NAO data the best but we also saw blocking over the Yukon which fueled an amazing and persistent stretch of winter-like weather over Vermont in the middle of spring. 

Much of Vermont did see a nice overperforming wet snow of nearly a foot in some places on March 23^rd, but the true “arctic spring” didn’t commence until around April 9^th. It was 5 weeks of remarkable spring cold and some substantial snow. So much snow in fact that Mt Mansfield had a 2^nd peak of snow pack in early May. More on that later. The 5 weeks beginning on April 9^th and ending around May 13^th was roughly 7 degrees below average and much of the high country didn’t see any 60-degree temperatures throughout April. We did see several rounds of snow, some elevation sensitive, some not so much. Though we never did see the epic April powder producer (that would come in May), I would estimate that Mad River and Sugarbush saw at least 20 inches of snow in April. It got even more incredible in early May. Following a spring-tease May 1-3, a massive surge of May cold descended on New England. A storm on May 8^th and 9^th produced 5-10 inches of not wet snow but powder across much of the northern Vermont high country. I will remember May 9^th for as long as I can remember the dates of all my favorite weather events. Sub-zero wind chills, temperatures in the 30’s all day, snow squalls and several inches of snow on the ground throughout the day. It was truly surreal! Then, in a total about face, a heat wave hit Vermont in a span of less than 3 weeks. Most official reporting sites in Vermont hit 90 degrees oddly beating locations such as Philadelphia and Washington, DC that have yet to see 90 degrees this spring (a rarity)

In many ways 2020 has not been a year we would ever hope for. It certainly was not a memorable winter season from a weather standpoint either but will obviously be remembered for worse reasons years from now. The 5-weeks of winter that the Vermont high country saw in spring has brought some optimism and provided a reminder of what CAN BE. I can hope, like the rest of us, that we can come to a resolution as to an appropriate way to face the challenges on the ground and have a ski season we can all enjoy. Look forward to being back next winter to serve the MRV like always. Until then, stay engaged and continue to work the make our community a special one and the world a better place both now and in the future.