Forecast trends drier with chilly temperatures prevailing though Dec 12 and a possible thaw Dec 14-15

Colder temperatures have arrived and a few inches of snow came with it. Tuesday was the beginning of an extended stretch of sub-freezing temperatures, but the forecast has trended drier over the past 48 hours. We also are expecting some of the cold to retreat somewhat during the middle of the month, but this "retreat" doesn't appear especially severe right for now and temperatures appear just slightly above average in the period starting December 13th to about the solstice which is about as far out as we can reasonably prognosticate.

Wednesday will finally feature more than a glimpse of sunshine which will help boost temperatures into the 20's along with relatively calm winds. Clouds are expected to return Thursday and some light snow is expected from a clipper system Thursday night. Honestly, I had higher hopes for this system as it appears totally deprived of moisture and appears way too far north for any late coastal strengthening. Still, it will bring with it another charge of arctic cold, rivaling the Thanksgiving cold outbreak with temperatures below zero Saturday morning and rising toward 20 Saturday afternoon. Saturday will feature more sunshine however which is a welcome sight during what is the darkest days of the season.

Forecasters are watching the big southern streamer which is expected to slam the Gulf Coast with rain and thunderstorms this weekend. By Sunday evening, the storm will continue to be a sizable weather producer centered near the Carolina coast. Given the right configuration in the jet stream, this storm could make a northward turn and cripple the entire northeast with snowfall but the circumstances just aren't right this time. The polar jet is retreating and a large ridge in the jet stream is expected to build over south-central Canada just as the storm reaches the coastline. This simply does not provide a clear northward or northeastward avenue for this storm to travel and its speed is expected to slow, perhaps even stall and thus keeping the impact area smaller. Some snow could certainly fall across inland portions of Virginia and West Virginia but at this point I would be surprised to see this storm become a serious New England impact, even in southern sections though one can never say never, not with northeast weather.

As mentioned in previous posts, the jet in the Pacific will be tightening and strengthening and will force the polar jet and arctic air to go into retreat mode. This appears to be a slow process right now however for a couple reasons. First, given the time of the year and the low sun angle, it will take some time for the cold air to erode and will need some advection to do it. Secondly, the Pacific will go into full "evil empire" mode. No, we could certainly do a lot better but we've also seen a lot worse. Temperatures are thus expected to remain below freezing through at least the 12th or 13th of December. Barring a miracle from the aforementioned coastal storm, snowfall will also be minimal but there is a small disturbance capable of delivering a light accumulation this weekend.

We are likely to see a round of above freezing temperatures and rainfall sometime around the 14th-15th of the month which coincides fairly well with the peaking EPO (Pacific Jet strength). There doesn't appear to be any mechanism to provide for the return of arctic air after the 15th but the pattern doesn't appear to be terrible. If I had to guess, temperatures would likely remain above average but we might be able to reintroduce the possibility for snow with what looks to be the continuation of a stormy pattern overall.

Cold returns in the short term but some critical questions remain unanswered for the middle of the month

We had to make a temporary retreat from our trip to fantasy island Sunday as temperatures warmed and snow changed to rain. After a balmy night, colder air will gradually regain control of the region's weather and another extended stretch of sub-freezing temperatures will commence beginning Monday afternoon. All of this has been well foretold but we have a nice addition to the incoming cold which comes in the form of a period of light snow during the day Monday. Nothing exceptional is expected but the northern Vermont high country (especially the very norther part) will see one to as much as 4 inches.

No complaints from me since I would trade snow for sun at any point during the ski season, but the sun is something we haven't seen much of going back nearly 10 days now. Our best chance for that comes Tuesday and Wednesday. I am not going to promise a lot, but we should see a few hours each day with better visibility and temperatures generally in the teens and 20's. On Thursday, an incoming clipper system should spread more clouds into the region and eventually bring some light snow. The clipper will also bring a re enforcing shot of stronger arctic cold. This means another day with some sunshine Friday,  but with temperatures hovering in the teens and then approaching the zero-degree mark Friday night.

The outlook for the upcoming weekend (December 8th and 9th) revolves around a potent southern streamer which seems poised to impact some part of the east coast. In truth, most of the weekend across northern New England looks just tranquil and cold. There are hints of a weak disturbance being the catalyst for some light snow Saturday with temperatures recovering into the low 20's after a near zero start. If we get any impact from the aforementioned storm, clouds from this arrive Sunday with precipitation arriving later in the day. Vermont is on the northern end of a range of the possible impact zones but a slightly different interaction of jet stream impulses could change the look of this storm quite dramatically so I would be hesitant to write this one off so early. The polar jet will also be in the process of weakening some around this time keeping the door ajar for east coast storms to make that northward turn under the right circumstances.

The weakening polar jet and retreating arctic air comes in response to a tightening of the jet in the Pacific. This topic has been center of debate activity as it relates to the weather pattern across the central and eastern parts of North America during the middle of December and beyond that into the Xmas holiday. The European model and its ensembles show a more resounding tightening in the jet which is illustrated well when one views how the model is simulating the changes in the MJO phase and EPO index (in both cases it predicts those will turn unfavorable). In this scenario, the pattern would turn more adverse for snow and cold in a very widespread fashion. Both the American GFS and Canadian Ensembles shows considerably less tightening in the Pacific however. The pattern does allow the cold to retreat some by December 11-12th but "El Torchy" would be very subdued and arctic cold would remain somewhat of a factor. No doubt this is a hugely critical question as we head further into December. In spite of the respect I have for the Euro model, I remain optimistic we can avoid much of that outcome for now.

Some milder air/rain Sunday is the only blemish on a good looking first 10 days of December then pattern may turn milder for middle of month

With the amazing month of November coming to a close, I wanted to take just a moment to savor what was one of the most stunning stretches of weather I've seen in Vermont. Some have implied that I have been guilty of some wishcasting in the past, but I don't think I would be even capable of wishcasting a month like this, even with 110-percent effort. Most of the state saw temperatures between 4-6 degrees below average, easily the coldest November of this young century and actual temperatures on the mountain averaged between 25-30 degrees depending on elevation. Most locations also doubled their monthly precipitation amounts, which is a somewhat unique element of November 2018 when compared to other unusually cold months in the November-March period. Most importantly though was of course the snowfall which was simply historic. Almost 6-feet across much of the northern Vermont high country and much of it remains firmly in place going into December. Simply driving above 2000 feet gives one a clear sense of the amount of snow on the ground right now and it's also quite a contrast to some low lying areas which saw substantially less snow this month and especially during the very elevations-sensitive recent storm. 

The first half of December promises to bring a bit of everything to the region. There are certainly some signs of trouble during the middle of the month which I will try and detail as best as I can but instinct has been telling me that this will likely be one those years when many warm-ups will get thwarted and that a healthy percentage of the snow that has fallen will help anchor the base for the duration of this winter and into early spring. That's intuition talking and hopefully not too much wishcasting.

In the short term, we will get a small stretch of tranquil weather including some very limited sunshine Friday or at least some decent visibility. Temperatures on the mountain will continue to remain below the freezing mark through most of Saturday when clouds will thicken in advance of a push of milder air. Precipitation will accompany the warm front, arriving early Sunday, perhaps as a brief period of snow and then changing to freezing rain or rain with temperatures hovering right around the freezing mark and eventually rising by the evening. Much of Sunday night will feature readings near 40-degrees which means some limited melting.

Colder air and snow flurries will push back into the region on Monday and although the polar jet has yet to attain any serious strength (it typically doesn't in early December), it will nonetheless begin to have an impact on the regions weather. Snow is likely to fall from at least one clipper-like system sometime during the middle of the week. We are also operating under the assumption that the active southern branch of the jet will keep its activity further south, but this is likely to be a dangerous assumption without an overpowering polar jet so we will have to keep an eye out for that as well. The less-than over-powering polar jet will keep temperatures on the chilly side. Certainly below freezing beginning Monday night, and some single digit overnight temperatures in the middle to later part of the week. The cold is likely to get re-enforced in some fashion for the weekend of December 8th and 9th and we certainly could see some snow along temperatures readings between zero and 20.

Though the colder air is likely going to carry us through at least December 10th, there are now more declarative indications of some key changes in the jet stream in the Pacific. Specifically, that dreaded tightening which is expected to focus much of the unsettled weather on the west coast for a time and allow some of the arctic cold to retreat over the middle to eastern portions of North America. The cold will retreat from middle sections of the U.S. first and will likely linger across New England the longest but the impact stremming from these changes in the Pacific will be pretty widespread and will ultimately lead to a few milder days, even for us, sometime between December 13-20.

Nice looking storm for the Vermont high country should yield 1-2 feet through Wednesday PM

What seemed like a garden variety event for the Vermont high country with some possible upslope-related upside has evolved into what appears to be the most exciting event for interior New England so far this season. This of course is saying alot with the three feet of snow that has already fallen in many areas. Temperatures will be marginal both Monday evening and throughout much of Tuesday but with the help of some elevation, accumulations could be very impressive and will likely give the mountains the most impressive pre-December snow-pack in recent memory.

This storm system has already left its mark on the Midwest with high winds and heavy snow and is expected to recenter itself somewhere near the New England coastline by very early Tuesday, using the relative warmth of the Atlantic Ocean to restrengthen one last time. The consolidation of this storms energy south of Vermont was not much of a question, but the rate at which this happens and where exactly does this happen has big implications for snowfall across the interior New England high country. Based on the information we have, the phasing, strengthening and position of this storm look fantastic. The coastal system will form near the southern New England coastline and track not far from Boston while strengthening quickly. Temperatures are certainly a bit more marginal than we would like, but that might only hold back accumulations for valley areas and really hurt the Champlain Valley which likely see only a minimal snow accumulation and could see more rain.

Mixed precipitation across the valleys and snow across above 1500 feet will begin Monday evening. As precipitation intensifies, I expect that all locations in the MRV will be snow, but the snow will be on the gloppier side in the valley. Higher up, any initial wetter snow should become drier as temperatures cool into the middle 20's and rain there through much of the rest of the storm. Snowfall rates appear the heaviest Tuesday morning and then will lessen to more occasional snow showers by Tuesday afternoon. Winds will be substantial at the summits Monday evening night but will gradually diminish as Tuesday progresses. We do have some lingering instability associated with this event and snow showers will continue through Tuesday night into Wednesday. The wind direction favors the far northern mountains for the best terrain enhanced snows but Mad River should scores some of this as well.

My guess on accumulations is this

8-14 by midday Tuesday

2-5 later Tuesday and Tuesday night

2-5 Wednesday - Wednesday night

Thus yielding an 84 hour total of 1-2 feet

Temperatures will remain relatively seasonable throughout the week and generally below freezing on the mountain. Snowfall should be pretty minimal Thursday and Friday and the next chance for precipitation comes in the form of snow thanks to a push of warmer temperatures on Saturday. This warmer push appears more subdued over the past few days but is still likely to lead to a period of above freezing temperatures later in the weekend into December 2nd and third. There remains a chance of some adverse precipitation types as well; but again, it doesn't look quite as bad as 48 hours ago.

As we progress further into December, the pattern looks just slightly favorable. We should get a decent push of colder weather sometime around December 4th and this chill should keep us in good hands through the December 7th-9th period. Teleconnection indices looked more mixed thereafter and the jet in the Pacific does show signs of tightening some with a large mid to high latitude ridge expected to form south of the Bering Sea. That's way out there though and I fully expect some fluidity in the outlook.

Happy early opener ! We've got a bit of everything over the next few days but we can still hope that the upcoming week is a snowy one

Happy opening day ! Skiers were greeted with a calm, crisp, great visibility morning on the single and an incredible amount of November snow on the hill. Savor this, cuz it won't happen much. We have lots of weather over the next few days and beyond. It starts very early Sunday morning as arrival of precipitation unfortunately coincides with the retreating cold. Though temperatures aloft won't be too far from freezing, models are suggesting that this warm layer is thick enough to prevent significant snow and precipitation instead will fall as rain or some freezing rain between 5 and 10 am. As Sunday progresses, the warm layer aloft will cool somewhat and the rain could mix with or change to snow, especially across the high country before ending sometime in the afternoon.  The melt will be pretty minimal, but rain is rain and the November powder party will temporarily get shut down.

The Sunday weather system has a follow-up act Monday/Tuesday that has looked more and more promising. The temperatures situation still looks tenuous but I think the mountain is on the right side of this "tenuous" . Even without the influx of any serious cold, this early week weather system is a deeper one and will be supported by the development of a coastal low pressure system which will help enhance the moisture fee and stunt any significant intrusion of warm air. Models have been simulating a wide variety of accumulation totals mainly because the rate at which this storm matures remains somewhat a question. Temperatures in low lying areas will also hover at or just above the freezing mark meaning a rather gloppy accumulation below 1500 feet while a drier snow falls across the high country. Though we still have time to raise expectations some, a 4-8 inch storm is my early first guess by midday Tuesday with lesser and gloppier amounts below 1500 feet.

The Monday/Tuesday storm is supported by a pool of general instability that will allow flurries and snow showers to continue through as long as Thursday. The wind direction later Tuesday, Tuesday night and Wednesday appears light but blowing from the west, southwest which is likely to focus much of the convective snow activity on the far northern mountains of Vermont. By later Wednesday that wind direction is expected to turn and become more northwesterly allowing some of those snow showers to impact areas further south. It won't be especially arctic with temperatures not too far from seasonable levels but remaining mostly sub-freezing on the mountains while creeping above freezing in the valley areas on Tuesday, Wednesday and Thursday. Colder nights will accompany some clearing very late in the week and this should set the stage for a sunny start and seasonable start to December.

We've had it very good the last two thirds of November. Certainly one of the snowiest I can remember in a while but no good thing lasts forever. The pattern actually remains somewhat favorable through early December but there are signs of a disconcerting warm intrusion around the 2-3rd of the month which coincides with a temporary weakening of the negative EPO which has been so incredibly supportive of this recent November snowy onslaught. Cold weather is expected to return by the 4th or 5th of the month and this is supported by negative Arctic Oscillation and what we expect to be some weaker ridging in western North America.

So long as we keep El Nino at bay, I expect plenty of snow to be on the way

'Tis that time of year again. The days are darker and many are gloomy, the weather has gotten continuously colder and lots of snow has already been flying across the Vermont countryside. Though many don't share our collective enthusiasm, we remain steadfastly proud of our affinity for winter. Without the colder temperature and abundant snowfall, all that would be left is months of incredibly short days and an unskiable Mad River Glen. So yes, we throw out the welcome mat for another winter season on the mountain and another season of talking weather on the blog.  As always, its always a privilege discussing this stuff with this cohort of winter weather fanatics, many of them skiers at MRG but plenty of others who engage in an assortment of snow-related activities across the state. 

The scary blob of red off the coast early this fall

I will admit to harboring some rather serious trepidation about the coming winter season through much of September. It wasn't simply the continuous stretch of warmth that encompassed all of New England from July through September but rather what I believed to be the major cause of that warmth. Though never attaining any serious attention from my blogging efforts, sea surface temperatures, regionally speaking, like within several hundred miles of the New England coast, do play a rather significant role in the weather across all of of New England not just coastal sections. There's some neglect to go around for not discussing SST anomalies more often on a regional level but I don't recall ever witnessing a time where sea surface temperatures in the Atlantic achieved such a warm state in a relative sense. The impact was undeniable and several of our favorite regional weather personalities made a point to mention the number of days featuring 70-plus dewpoints or 65-plus dewpoints or the number of nights where temperatures failed to break 70 or 65. It may not have been the hottest summer on record, but was arguably one of the more humid summers in a generation and perhaps more. Furthermore, coastal areas were hit with a succession of heavy rain events, many of which caused localized flooding and have largely contributed to well-above normal rainfall amounts for the year. Vermont has largely avoided this and rainfall amounts of remained in the rather ordinary range during the summer and also during the autumn months. The anomalous warmth persisting in the coastal Atlantic Ocean waters and the apparent feedback resulting from it, on a regional scale, caused a bit of a fire alarm regarding my thoughts on the upcoming winter. We had to somehow rid ourselves of this warm blob in the Atlantic or else face some rather difficult headwinds. Fortunately, we have for the most part. Whether it be attributed to the pattern shift in mid-October, localized storminess or localized chaos of ocean currents, much  of the warmth that was focused along the New England coast has been swept well to the south and water temperatures have returned to normal, and with that, we can go back to our regularly scheduled programming. 

Sept SST's 

Nov SST's 

What's up with El Nino 

The state of the ENSO invariably plays a large role in pre-season outlooks and along with the aforementioned coastal Atlantic Ocean water temperatures, raised some alarms. Us Vermont powderhounds are likely still feeling pretty wounded after the 2015-2016 Super Nino abomination. Any talk of a coming El Nino is thus not likely to foster much positive energy. Though those feelings are quite understandable, large distinctions need to be made regarding various ENSO events and the stark differences between the varying intensities of El Nino and the overall impact it has on New England winters. The Super Nino years, particularly the last two ('97-'98 & '15-'16) both featured exceedingly mild temperatures and only in the former were we able to scrape out some halfway decent snowfall. Many of the El Nino years in our recent sample size however can be more accurately catorgorized as weak or garden variety and those have yielded considerably different outcomes for Vermont especially on the temperature side. The concern this year was that a weak El Nino would quikcly evolve into a much stronger event but those concerns, just in the last two weeks have eased as temperatures in the critical regions of the equatorial Pacific have relaxed somewhat.

This isn’t to say that garden variety El Nino winters or weak El Nino winters guarantee us a season of epic ness. The many in our sample size have yielded mixed results but one thing is clear in the aggregate, El Nino’s of the “weaker” variety have a much more subdued impact on temperature. Furthermore, a few in our sample size that I’ve shown below turned out to either somewhat or even more significantly epic. The key figure to watch are those actual SST anomaly values in the critical regions of the equatorial Pacific. If we can keep those numbers below 1.5 C or better yet 1 C above normal then we have a much better shot at avoiding the extended blowtorch that often accompanies stronger El Nino or Super Nino winter seasons. Let us not forget that there is one very positive byproduct of most El Nino, the revved up southern branch of the jet stream, responsible for juicy southern streamers that have been known to produce big east coast snows across both coastal areas and the interior. We’ve already gotten one of those and we aren’t yet though November. So long as we can keep El Nino somewhat alive there will be more to come. 

In the below graph, I color coded the temperature results and then gave a verbal description of how the actual snow season was. 

Watching the Pacific as always 

The next variable on our checklist is the PDO or the Pacific Decadal Oscillation. We’ve watched this “bad boy” every year. The PDO describes the configuration sea surface temperature anomalies across the mid-latitude more generally and geometrically as opposed to the ENSO (El Nino/La Nina) which specifically relates to whether water temperatures are above or below normal in equatorial regions. At first glance, the PDO doesn’t appear to tell us a lot this year. The last reading of .09 is pretty neutral on the scale of things. The super +PDO winter of 2014/15 had an index well above 2 by way of comparison. That said, water temperature anomalies, specifically in the Gulf of Alaska and over the Bering Sea have been especially noteworthy. 

The Bering Sea water temperatures have a lot to do with the incredible loss of sea ice in that region over the last years. Yes, some of it relates our warming climate which has had strikingly massive impacts at high latitude regions such as the Bering Sea. Some of it is also variability. The Bering Sea is just a particular region where sea ice has been running especially low recently, in other arctic regions, it has been higher. The loss of this ice however and persistent warmth in that region has created a blob of anomalous sea surface temperature warmth that is especially noteable. When climate scientists attribute mid-latitude cold waves to the warming climate, they are often referring to the altering of the polar air pathways that are induced by some of these sea surface temperature features. In the case of this year, much of this warmth in the Bering Sea extends to the Gulf of Alaska. If this blob of warmth remains in this locale, the pattern will tend to favor more high latitude ridging in western North America and troughing and general storminess focused on eastern North America. Interestingly, this is exactly what has transpired when this particular sea surface temperature pattern developed. 

Seasonal SST Animmations in Paciific Ocean

Snow and Ice expansion so far  

Last on the list of “measurable” variables is the build-up of snow and ice on a hemispheric scale. Though one can argue on the validity of some of the inferences drawn from using this data, I tend to be among the people that considers it an important item to watch. We’ve seen some very healthy build-ups of snow in the autumn months over the last 6 winters or so. A few of these winters turned out to be pretty cold, and a few were taken over by El Torchy. The build-up of snow actually got off to a pretty slow start this autumn but picked up substantially in October and the final number that month was 20.06 (millions of square KM’s). This is above the 50-year average but the lowest value since 2011. It’s probably not a good year to use this variable as a serious determinant and focus instead on other factors.

Snowcover departure  

Interactive Sea Ice Chart  

Any tells ? 

Lastly, I want to focus a little on any atmospheric “tells”. You know, how a seriously flawed Texas Holdem player might act when he gets dealt a pair of kings and manages to get the entire table to fold before any bets are placed. Mother Nature is actually a much more skilled poker player. She might reveal a few things about the way she might behave in advance of a winter but she can throw a bluff your way as well and lead you straight to prognosticator purgatory. Still, who can’t resist a game of poker with Mother Nature so lets play. 

The two things that stand out about the weather in the past 6 months is what was mentioned above about regional sea surface temperatures in the North Atlantic. We absolutely needed to rid ourselves of this plague and we did it in the nick of time. More importantly, it is the way we did it. An abrupt pattern change that allowed the weather to go from summer in Vermont with warmth and humidity in early October to snow and very chilly temperatures in late October. Since then the pattern has largely been driven by a very negative EPO or loosened Pacific Jet. Long gone is any hints of an “Evil Empire” in the Pacific and this has stood out to me and largely driven the very cold/snowy pattern in recent weeks. Basically, we needed something overwhelming eliminate some of that problematic ocean water on the Atlantic Coast and we got it. The EPO, the Andrew Benintendi of variables, coming through in the clutch turning around what appeared to be a less than mediocre winter outlook. 

The actual forecast for this season 

So lets get some of that “Andrew Benintendi” into a forecast for the winter. I still retain a bit of consternation on temperatures. El Nino is El Nino and most of those are on the warmer side of average, even the weaker ones. If we keep El Nino in check, the adverse effects on temperatures that we typically see in strong ENSO winters will be negated mostly by the EPO, which seems intent on assuming a more negative state for reasons discussed above though it will fluctuate. When the EPO does fluctuate we are likely to see some adverse conditions. Overall, I would still predict that temperatures come in on the above side of average aggregating over the entire ski season but not by much. If the forecast period begins on opening day, now slated for November 24^th and ends sometime in early to mid April, I would expect temperatures to come in between 0-2 above average. Last year came out about +1 over the same period which as you might remember, including both some very cold and some very warm. 

Where we should see a noticeable difference relative to last year is on the snow side. The winter storm which slammed the eastern seaboard on November 15th, foreshadows what I believe will be a very active winter full of juicy east coast storms systems. The combination of the weak El Nino and negative EPO will be the culprit for what I believe portends a stormy winter season. We have to expect a significant slump in conditions at some point and we also have to hope that the storm track is favorable enough to deliver us a chunk of the goods. My expectation however is that it will, we will have an above normal snow season, and a good ski season overall shared largely with other locations across the eastern United States. So with that, another season begins with the earliest opening I can remember in at least 15 years.Get after it !

Winter 2017-18 gets high marks for longevity and resilience but one can't forget the nasty interruption

If nothing else, one has to admire the persistence and certainly resilience of this most recent winter. After reaching 70 degrees in parts of the Mad River Valley on February 21st, the mountain failed to see any matching warmth until late April or early May. The past winter was unique for its longevity and appreciated for the longer, more sustained cold outbreaks. That said, the 7-week stretch which began on that catastrophic Friday January 12th and extended through February was very unappreciated and severely crippled what is traditionally the heart of the Vermont ski season. A 2nd straight March recovery was epic, but it would be nice if we could reach March without needing a "Hail Mary" to save the season. 

Going back to early last autumn, it looked as if the unabated succession of anomalous warmth across eastern North America had broken. The summer was milder, autumn appeared to be arriving quickly and perhaps we could align ourselves for a succession of cooler months that might extend through the cold season. Then, for the 3rd consecutive year, Vermont experienced an autumn blowtorch with summer-like heat late in September and very warm weather for much of October. When "El Torchy" type patterns linger for such a duration, I tend to get concerned there are extraneous sea-surface temperature forces that are steering the outcome. Indeed, one could make that case given the configuration of sea surface temperature anomalies in the mid and high latitude Pacific and what appeared to be a building La Nina in the equatorial Pacific. Some of those sea surface temperature anomalies shifted in November however and the blowtorch abruptly ended. Winter didn't exactly break the door down in November but it did make itself known. Temperatures were generally below average and the mountains secured 10-15 inches of snow by the Thanksgiving holiday with a favorable looking pattern emerging for early December. 

The Arctic Oscillation (AO) provided a massive boost for the colder weather both in November/December and the season generally. By way of comparison, the 2016-2017 winter featured an AO that averaged over an index of 1 which in the aggregate is quite substantial while 2017-2018 featured an AO that was a shade below zero. The effect of this was felt instantly. Though the state saw a few mild days very early in December, a somewhat blocked arctic combined with ridging in western North America to produce a nice succession of sub-freezing temperature days beginning around December 7th. Lighter snows accompanied the colder weather initially but a clipper system arrived on December 12th, blew itself up into a full fledged winter storm and deposited over a foot of snow on the high country by the end of December 13th. For almost 2 months (way too long thinking back), the 12/12-13 event was the best of the season. The colder weather was more of the garden variety type through mid December but the pattern strengthened as the month progressed. There were significant questions relating to all this, as it appeared that a developing block across Alaska would be in direct competition with a building ridge across the southeast United States. Would another Christmas holiday feature a big thaw or would arctic air prevail ? In the end, the arctic cold won and won big. Christmas weekend saw some snow to ice and Christmas Day featured some powder though not as much as we might have liked. The ensuing days were brutally cold with temperatures spending much of that period between December 27 and 31st below zero. 

The onslaught of cold continued into the New Years holiday weekend and through the first week of 2018. All sorts of terms were thrown describing the deep freeze, my favorite being "The Arcticgeddon". Though it was impressive, sustained outbreak of extreme cold are not uncommon and typically impact much of the eastern seaboard every 2 years or so. For Vermont, the cold rivaled and even exceeded in some instances that of February 2015 with nighttime and morning readings of -25 and daytime temperatures failing to climb above zero both on January 1st and 2nd (the coldest two days of the winter season). The northern green mountains were hit with a unique warm advection snow event late on January 2nd, but for the most part, the period after Christmas through the first few days of 2018 was dry thanks to a suppressed storm track and the very shallow stable layer of cold that typically accompanies the polar vortex type events. Coastal areas did get a big impact from what many referred to as the "bomb cyclone" on January 4th. Meteorologically speaking, this was a truly mesmerizing storm since it strengthened to a hurricane-like intensity (~970 mb), producing 30-50 foot swells along the Massachusettes coast that were captured in full fury on YouTube (I highly recommend looking this up if you haven't seen it). I've provided another link here 

Scituate, MA video from 1/4/18

The storm stayed offshore but nonetheless caused a healthy swath of cold, powdery, snow in coastal sections and grazed Vermont with a few cold inches. Wind chills were 40 below or lower at the summits that day and into Friday making the skiing a bit of a challenge, but the snow was piling up and the season (aside from the extreme chill) seemed to be firing on all cylinders.

And then came January 12th. There were some glaring signs that the arctic cold would make a big retreat during the back half of the month and a rough 1-2 weeks of skiing was likely state-wide. The actual weather played its own little tune however, improvising quite a bit and deviating verses many of the expectations put forth early in the month. The January 12th event was some seriously bad improv. A combination of features in the jet stream conspired to produce an absolute worst case scenario for New England skiing. This combination included a somewhat phased amplified jet stream across the high plains and a resilient upper air low pressure center over Florida. The surge of warmth across New England was simply overwhelming and was accompanied by rain, high winds and temperatures well into the 50's. The 24-plus hours of all this was simply too much or much of the snow pack, even across the high country. Yes we retained a minimal amount of snow when the snow and sleet returned by Saturday the 13th (MLK weekend) but it wasn't much and thus the Vermont "frozen hellscape" as one follower of the blog called it had officially commenced. 

The improvisation actually continued for another week in January, as arctic cold made an impressive southward surge thanks to the formation of a powerful ridge in the jet stream which took up a position over the Canadian Rockies. The surprisingly strong outbreak of widespread cold provided a golden opportunity for a quick recovery but all of the precipitation and specifically snow was confined to areas well, well to the regions south or well offshore.  And then the cold finally did retreat as the MJO cycled out of the more favorable phases allowing the jet stream to tighten and the infamous "evil empire" to set up shop north and east of Hawaii. January ended quite horribly with lots of mild weather, mixed precipitation or rain and only isolated days of colder weather that included little if any snowfall. Hope came alive toward the end of the month in the form of what appeared to be a much improved weather pattern in February, but the weather continued to improvise and prognosticators that opted to marry themselves to specific ideas regarding the February weather pattern were taken to the woodshed yet again.

February indeed started promising and included both new snow and colder weather. Man it looked good too, especially for those weather enthusiasts that love to hyper focus on the MJO which I can tell you from experience is not running in short supply right now. The MJO had, as expected, move into some of the mild phases in the cycle during the latter part of January but was proceeding very quickly and a 3 year old could have quite easily extropolated that the MJO was riding toward glory in February. Extrapolating the MJO is a dangerous game however, about as dangerous as over-emphasizing the cycle as the single best determinant for the ambient North American weather pattern. Everything was on track initially with snow falling late on Superbowl Sunday and then a foot of snow falling during the middle of the week from a garden variety system that tracked beautifully for interior New England. It all fell apart thereafter however. The MJO stalled, the ridge in the jet stream across western North America fell apart and it finally started to snow across Colorado which had been barren for the entire season. It began to get mild across Vermont by the weekend of the 10th and 11th and then it got milder and then even milder. We got some rain, we lost some snow and then we got more rain and lost more snow. Then the mountains got 60-degree weather on February 21st and many places at 2000 feet had little if any snow. By the end of the month it appeared hopeless. Though improvements were right around the corner, the snow was almost entirely gone below 3000 feet. Pictures taken at Mad River Glen on April 30th show more snow on the mountain verses what was present during the last few days of February. It was a truly depressing state of affairs

  

Morale always takes a beating during blowtorches and meltdowns and in recent years it has been accompanied by doom, gloom and despair. Each round of anomalous warmth always brings discussion of global warming/climate change and comments are often suggestive that winters are "going, going gone" as are decent ski seasons. All of this is actually true if the warming experienced over the last 150 years persists for another 200 years or beyond. Generations from now, winters in Vermont might be unrecognizable compared to what we are typically accustomed. We as a globe have to make it a priority to rethink our carbon footprint if we are to conquer this challenge. All that said, global land and sea temperatures have moved up about one or two hundreths of a degree F every year. Speaking strictly in the scales of geological time, these are alarming changes. They are not changes however that can be easily separated from typical statistical noise associated with variability which as we all know occurs through time and across geographical space. Cold happens, warm happens, storms happen, drought happens and all these things will continue to happen regardless of climate changes. Attributing each anomalous weather event to global warming and climate change introduces some sketchy science unless compelling scientific and data driven arguments are made to support such assertions.  Hurricane season seems to bring out some of the worst actors in this regard. Though warmer water temperatures undoubtedly support stronger storms the available data has not suggested that hurricane activity in a general sense has increased at least during the satellite era. The climate change/global warming issue is a vital one that requires a mass movement just for general awareness. Like any movement of this scale and importance, there are going to be bad actors that rely too heavily on bad science or are simply using the platform to garner attention for themselves. If you are one that tends to be disinclined to take the climate change issue seriously because of characters like Al Gore (who I don't consider the worst actor but is still guilty of using reaching scientific arguments to make his case) I would try and move past it and understand that although some of the alarmists might be seriously wrong about their claims, one still has be extremely concerned about what the climate might look like 100, 200 or 300 years from now. 

One glaring, completely non-sensationalistic example of some early manifestations of climate change is the ongoings across the Arctic and specifically Barrow AK. Barrow, also going by the more indigenous name of Utqiagvic is considered, by some, to be one of the oldest inhabited towns in the United States, sitting at the northern most point of Alaska bordering the Beaufort sea and the vast but rapidly decreasing plate of arctic sea ice. Barrow is a place of -80 degree wind chills with an economy that is geared toward local oil exploration or feeding itself through whaling, fishing or hunting. The town, which remains majority indigenous is a place where memories are stored and past forward over multiple generations and where changes in the climate have real impacts on daily life. And it would be difficult to find a place anywhere in the world where those changes have been as dramatic. The autumn months in particular have been running warm and the weather was so incredibly anomalous during the last few months of 2017 that a statistical algorithm automatically flagged the data and tossed it out of the global aggregation. A more detailed narration of this occurrence can be found in the write-up by Angela Fritz of the Capital Weather Gang in December. 

 

Barrow, AK - This city is warming so fast, algorithms removed the data  

 

In a span of just 20 years a typical October has warmed almost 8 degrees F, almost 7 degrees in November and almost 5 in December. The warming, especially at this latitude is a direct result of climate change and on multiple fronts. Almost every month has experienced at least 1-2 degrees of warming but the autumn months have been especially dramatic because of the dramatic loss of sea ice. 50 years ago, the arctic would usually freeze by October and is now remaining unfrozen through part of November. Barrow has literally become a maritime climate for two additional months. Though there are several visible signs of what has already occured, Barrow stands out to me as being one of the most glaring.

Back to Vermont and the incredible "don't call it a comeback" (yet it really was) month of March 2018.  The month rolled in with the snow mostly obliterated and MRG looking at “practice slope” only conditions and Stowe was forced to cancel their annual cross country derby for the third year in a row. Once again, a Hail Mary was needed to extend the season in any material way.

The pattern looked promising even as the February torch was annihilating what was left of our snow. The pattern change was triggered by the formation of an intense block in the jet stream over Greenland to go along with a negative Arctic Oscillation (AO). Interestingly, there was no available mechanism in the jet stream to transport significant amounts of cold in New England so that hope was that the pattern would deliver simply through sheer storminess and deliver it did. Big storms impacted the northeast on March 2nd, 7th-8th, 13th-14th and 21st-22nd. Not all of these big weather systems impacted northern Vermont; in fact, MRG was hardly the best spot, but during this crazy March, one didn't even need to be in the best spot. The first storm on March 2nd was the most impressive meteorologically speaking, causing wind damage and power outages along with producing heavy wet snow. Most of the snow missed northern Vermont, smacking the Catskills instead with 2-3 feet and delivering a foot to southern Vermont. Mad River did better from the subsequent storm on March 8th and though the storm was notable for the intense 5 inch an hour band that smacked suburban New Jersey, General Stark was back in business to the 1-3 feet that fell by Friday March 9. 

15-30 inches were back on the ground and March 13th had yet to arrive ! Our recent propensity for recording big storms around that date was further ironed into Mad River Glen tradition this year when for the 2nd straight year our best storm smacked the mountain. Though certainly not the strongest system to impact the northeast that month, the set up was absolutely perfect with the block across the Davis Strait prohibiting the storm from a clean getaway and allowing for continuous snowfall for roughly 60 hours. From virtually nothing to some of the deepest snow since 2015, March of 2018 was one of the more remarkable turnarounds. Vermont mostly missed the next big east coast system on March 21st and then received some mixed precipitation and rain during the last few days of the month.

As snowy as March of 2018 turned out to be, it was not especially cold. Temperatures averaged out to about normal during the month and bitterly cold arctic air never really became a big part of the equation. All of this changed ironically when April came around. The blocking in Greenland disappeared and eventually reemerged in a rather substantial way over Alaska and within a few days, extreme cold began making big hard charges southward. Temperatures averaged 7 degrees below normal for the month and when all the numbers are tallied, it will likely rank as one of the 10 coldest April's on record. One would have thought that with all that cold in April, the snow would also fall in abundance. Though enough snow did fall to bring the seasonal total up past 200 inches, the total for the month was actually a little disappointing and only in the vicinity of 10-15 inches or so. Much of the snow that fell in March however, continued to remain on the ground through most of April. As of early May, snow remains across the high country and the growing season is only finally readying itself to commence for the year. 

In the end 2018 managed to provide a little of everything. Though the snow season and Sugarbush ski season extended to nearly 6 months, February has to stick in one's craw. The traditional peak of the Vermont ski season was torched away by warmth while especially intense bouts of winter in varying forms ravaged Vermont both prior to and after February. The season was decidedly colder than the previous two, accompanied by either normal or below normal temperatures in November, December, January, March and April. There was plenty of snow across the northeast as well, but northern Vermont simply was not in the best place for it. The over 200 inches recorded by the end of April is within the vicinity of normal but a vast area beginning not far to our south recorded well above normal snowfall. Compared to normal, here is a breakdown of how certain regions did surrounding Vermont. 

Southern Vermont: 125-175 % of normal 
Coastal New England: 125-175 % of normal
Maine: 100-150 % of normal 
NYC/The Catskills/The Poconos/Jersey: 150-250 % of normal
Mid Atlantic Region: 75-125 % of normal 
CentralAppalachian (PA/WV) 125-175 % of normal
Southern Snow Belts: 150-250 % of normal
Northern Snow Belts: 75-115 % of normal

Northern Vermont in regards to snowfall was actually on the eastern edge of a broad area that extended through the Upper Peninsula of Michigan that under performed relative to their southern counterparts. In the case of Mad River Glen, it was simply being too far northwest for the most intense areas of precipitation. It seemed as if almost every storm got the mountain a little but only a select few got the mountain a lot even though we had so much winter to play with. It's all apart of the history books now and hopefully most that follow the blog got a chance to play in it a bunch. Enjoyed the effort once again as always and will be talking winter once again on the other side of the upcoming summer.