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 !