Terrific early season weather pattern prevails through at least the middle of December !

Beautiful Thanksgiving snowfall in northern Vermont was scenic and brought us a step closer to opening day. It appears Sugarbush has a tentative opening planned for December 1st but I have no inside intel aside from what the website is showing except to say that favorable snowmaking conditions will continue for the upcoming week and beyond. 

The prevailing west flow encompassing both the eastern Great Lakes area and all of New England is a dry one for Vermont. The lake effect snow bands tend to ring themselves out over the Adirondacks and the moisture from Lake Champlain is typically deposited in areas from Stowe northward. The high country will remain sub-freezing atop our new found late November snow, but addional snow showers will be light through the weekend and I would extend this outlook through much of Monday. Temperatures on the mountain will stay within a 10 degree range of 15-25 and generally below 20 in summit locations through this time in spite of some limited sunshine. 

I've been looking for that flow to turn more northerly and tap into some of that relative warmth from Lake Champlain and the opportunity for that, though limited, appears on the forecast maps Monday evening into Tuesday. If we can get a few inches, it would be of the very powdery and fluffy variety accompanied by temperatures in the low 20's. Those wintry readings will continue into the later part of the week when a much more impressive looking clipper system brings us our next decent show at some significant snow late Wednesday into Thursday. This storm has the capability of attaining some additional strength as it interacts with the warm coastal waters of the Atlantic Ocean and this opens the door for some higher upside potential. A more significant chunk of early season arctic cold will then envelop Vermont on Friday and into the first full weekend of December. Daytime temperatures might fail to break 20 degrees either Friday, Saturday or both. 

The pattern overall appears supportive of colder weather for the first half of December thanks again to favorable jet stream conditions in the Pacific. The American Ensembles shift some of this colder weather westward around December 14th/15th. By contrast the European Ensembles manage to keep some of the ridging structure alive in western North America while the weakened Pacific jet conditions are shown to at least somewhat persist. Even the possibility that the colder could persist beyond the 15th would suggest one of the best December setups in years for Vermont ski country. 

8-14 inches for the Thanksgiving holiday and yes, not all the forecasts agree with this yet !

Our white Thanksgiving is on track and on target. Over the past 24 hours and especially in the last 8 of those hours, models have converged on a scenario only slightly different than the one I proposed a few days ago. If we allow for one more northward nudge, a foot of snow is likely for Mad River Glen and Sugarbush. The National Weather Service in Burlington does not totally agree with this thinking and the point and click forecasts for the Waitsfield covered bridge are indicating less than an inch of snow for Thursday with the same Thursday night. Though this would seem to indicate that us weather people are not on the same page, we aren't too far apart either. NWS has central and southern Vermont painted in a Winter Storm Watch and this extends as far north to southern Washington County, but not quite to Waitsfield or Warren. I wouldn't worry about it as I think they will make a more favorable adjustment before the end of the day. 

Snow should begin in the vicinity of 8 or 9 am on Thanksgiving and fall at a rather steady rate through late in the evening. This a a very garden variety Vermont snowstorm with a benign area of low pressure in the Ohio Valley gathering a bit of fuel on the Atlantic Coast and depositing a swath of snow across central New York and interior New England. The one adjustment I would make relates to the snow consistency. Temperatures do not support a powdery snow in valley locations and will be hovering around the freezing mark through much of the day. Readings will be closer to 30 degrees around 1,600 feet (MRG base) and 25-28 closer to the summits which does support a drier snow. The moral of this story is to prepare yourself for varying snow consistencies if you venture out. I continue to expect snow accumulations of 8-14 inches. The heaviest area of snow might be south of MRG but I expect at least a 4 inch snow as far north as Stowe so I am surprised how bearish the snowfall forecast from NWS looks for some of these areas in northern Vermont. Again, I would fully expect them to adjust  by the end of the day or early tomorrow. 

A pattern supporting a widespread area of below normal temperatures in eastern North America remains on target beginning this weekend and persisting through much of the first half of December. What a sight to behold watching the EPO crash deep into negative territory the way it has for the back half of this month. There are a lot of warm feedbacks that need to be dealt with stemming from the onslaught of warmth that has persisted through much of 2024. Much of eastern North America will be enveloped with colder weather for the next 20 days giving us the opportunity to neutralize much of this as we proceed to the core of the cold season. 

Divergent westerly flow in Vermont will give the region an opportunity for some sunshine both Friday and Saturday. Most of both days will be sub-freezing with the exception of the afternoons in valley areas. Over the mountains, light snow showers and flurries will be more prevalent though accumulations will be minimal and confined more to the snowbelt areas of New York state and Jay Peak which tends to do better with west or southwest flow. More clouds and a period of steadier snow are possible for Sunday as the flow turns north. Temperatures will then remain in the teens and 20's for the first week of December with snow possible from a weak clipper on Wednesday and perhaps a stronger one later in the week.

Thanksgiving snow and plenty of early season cold weather to follow through early December

 A beautiful early winter pattern stands directly in front of us as the thanksgiving holiday approaches. It's been a struggle in New England to sustain any type of below normal temperatures over the past year, but an excellent stretch of cold begins Tuesday evening thanks mostly to a very favorable EPO set up in the Pacific and some high lattitude blocking over the northeastern Eurasian continent. The best part of this story is the snowfall which comes in the form of a significant dose on Thanksgiving and this storm will give the whole region a very wintry feel that will extend well into December thanks to the pattern. 

A moisture-starved storm will bring some rain and mixed precipitation to much of Vermont as passes over the Ottawa River in Canada early on Tuesday. Some snow can be expected close to the Canadian border but not much south of that. Drier and colder air will then settle in Tuesday evening which will begin what we hope is a multi-week stretch of sub-freezing temperatures on the mountain. Such an occurrence isn't easily achievable in the middle of winter and is a special sort of challenge in early December. 

Our Thanksgiving storm gathers its moisture Wednesday over the Midwest and will continue to strengthen as it moves over the Ohio Valley during the evening. Models continue to jostle over the track which is a bit surprising at this stage in the game, but I feel very comfortable betting on the Euro output which places Vermont in one of the better areas for snowfall on Thursday. Northward shifts are always a good bet, but are especially likely to happen early in the season thanks to what is usually a weaker polar jet and thermodynamic feedbacks from the Great Lakes. This track, would place the storm just west of the New Hampshire seacoast for Thanksgiving dinner and then up through eastern Maine after that. A classic holiday snowfall would be the result, beginning early on Thursday and continuing well into the evening. The snowfall would be widespread, falling both over valley areas along with the high country with elevation impacting snow consistency more than anything else. Some mixing with sleet and or freezing rain is a very real possibility early Thursday evening. Those details need to be ironed out in a day or two. In the meantime we can establish some early snowfall expectations of 7-15 inches. Without the mixed precipitation threat, I would go higher, but I expect a powdery finish to this storm regardless with a chilly, wintry and snow showery Friday (even though the accumulating snow should remain closer to the Great Lakes). 

A weak mid latitude Pacific jet set up (synonymous with -EPO) will combine forces with the aforementioned high latitude blocking scheme with the trifecta support coming from ridging which is expected to develop in western North America over the next week. This means cold weather through December 10th that will undoubtedly be accompanied by additional chances for snow. Almost all early season cold setups produce snowfall in northern New England and I would fully expect multiple chances at some snowfall next week. Champlain enhancement will contribute as might a storm that models have yet to resolve. A very encouraging start to the season which will produce plenty of snow clover, snow showers and sub-freezing temperatures as Mikaela Shiffrin skis for her 100th win this weekend at Killington this weekend.

Winter Outlook 2024-2025 arrives just in time for a colder pattern change

2024 has been the year of persistent warmth and following 3 flooding events over the past 18 months, autumn suddenly turned very dry. We thus head into the upcoming winter in need of some precipitation of off all types to avoid running a further drought deficit.  Though they're a few encouraging signs out there in the outlook, one rather bad one looms over everything. In the mean time, the short range outlook appears very encouraging with snowfall in the forecast over the high country over the next 5 days and more snow and cold on the horizon around the Thanksgiving holiday and beyond. With that introduction, lets take the plunge into another season. 

Upcoming Snowfall 

Going to start by providing a brief outlook for the upcoming storm, a system that is certainly not atypical during the early or later part of the ski season and one that is very reminiscent of a few of the bigger events from last year. While low pressure is stalling out over southern Manitoba, there will be an extended opportunity to gather moisture from the Gulf of Mexico and Atlantic Ocean which will give rise to a more robust coastal low pressure center late Wednesday. Rain will enhance and spread very slowly northward. When precipitation finally arrives midday Thursday, the deeper occluded low will swallow the coastal system allowing the already marginal temps in valley locations to warm a few more degrees and this means mostly a rain event in low lying areas (at least at for a while). Way up above 3,000 feet, precipitation is likely to fall as some wet snow late Thursday and continue through Thursday night but even at this elevation, temperatures are marginal and only support a few inches of very wet snow. Forecast models then are indicating a break in the action before an additional colder round of precipitation arrives for Friday night into Saturday. This should produce snow everywhere (even on the valley floor) though heavier snowfall amounts will remain confined to the high country and the more powdery snow should stay above 2500 feet. Still, the snowfall is expected to persistent at least intermittently through Sunday and where temperatures are the coldest, closest to the summits, snowfall should pile up modestly. By Sunday evening, expect 4-day totals of upwards of a foot while a 1-3 very wet inches can be expected near the valley floor. There is better dynamic support for heavy snowfall over the Catskills of New York and Pocono region of Pennsylvania on Friday. Much of this will melt early next week and should provide some needed drought relief to some very dry areas of the northeast. 

 

I have some deep concerns about the EPO this winter and the presence of the dreaded evil empire in the Pacific Ocean, but its not showing up in the outlook through the rest of November into early December. Quite the opposite is in fact, with a favorable jet stream in the Pacific, opening the door for stronger shots of cold weather and additional snowfall around the Thanksgiving holiday and into the first week of December. We discuss all this in subsequent posts. 

ENSO Outlook

In the meantime, lets start with discussing the ENSO situation for the winter. This is one key area where we are exceeding some of the more dire expectations earlier this year. Following last year's strong ENSO event which was approximately a +1.7 C El Nino, the exceptions of a nearly equally strong La Nina appeared to the prevailing view of those that both follow and prognosticate on ENSO. Sea surface temperatures in the equatorial regions of the Pacific have certainly trended in that direction, but after tiptoeing into negative territory, sea surface temperatures have stabilized and have headed back to near neutral levels. This has defied conventional wisdom. The last forecast I read from the NOAA folks continued to predict a weak to moderate La Nina, but I have very little confidence in such an outcome and would favor a more neutral ENSO as a best guess for the winter at this point. 

We certainly could use all the help we can get from ENSO neutrality. Many of the coldest winters, especially since Y2K have occurred during these ENSO conditions including the 2002-03, 2003-04, 2013-14 and 2014-15 and some of the biggest torches have occurred during strong ENSO winters of either the El Nino or La Nina stripe - think 2011-2012 and 2015-16. Boy, I would love forecast a cold winter on this rationale and its certainty tempting to run with this as the medium range outlook continues to trend colder. I can't do it however and the following paragraphs detail as to why.

PDO Outlook

Those that have followed the blog might remember that I keep referencing this current adverse -PDO stretch we are in. 2018-2019 was the last relatively neutral PDO winter and was also the last time we had a complete freeze of Lake Champlain. Since then the PDO has become more and more negative with each successive winter. This past October, the PDO nearly set a record recording its second lowest October reading, -2.48. in a dataset spanning over 100 years and a top 10 lowest readings for any month. 

 

The Pacific Decadal Oscillation or PDO is an index that describes the configuration of sea surface temperatures in the mid-latitude Pacific. No, it is not the defining predictive indicator every year, but the continuous negative state keeps relative sea surface temperature warmth in the mid-latitude Pacific with relative sea surface temperature chill both in the higher latitude areas near the Bering Sea and near the Equatorial regions (which would power La Nina, if it were to ever occur). This type of configuration does not encourage the sustaining of favorable jet stream conditions in the Pacific and instead favors the tighter jet stream flow that has a propensity to repel the southward transport of arctic air. There is a nice illustration when comparing October SST's of this current year to those that prevailed before the last cold winter we had in 2018-2019. 1st map shown is 2018 October and the 2nd is the most recent October.

 

PDO indices are cyclic by nature and this current more adverse stretch will ultimately cycle into something else. The PDO is also a better (and certainly not perfect) predictor of temperatures as opposed to snowfall. For coastal areas of New England and the Mid-Atlantic another year without the more constant presence of arctic air is a good enough reason to predict another bad snow year, but many of these years end up being respectable across interior locations as has been the case over the last two seasons. 

Snow/Ice Expansion

The buildup of snow across the northern hemisphere is running about average. The October value came in at 18.88 millions of square kilometers which is right in the middle. The buildup of ice in the arctic is slow relative to average but it remains faster than 2016 and 2020. The arctic refreeze time continues to trend slower over the longer term and this IS a direct result of climate change. Every 5 years or so, there's a noticeably larger area of open water that needs to refreeze and the Hudson Bay, which remains 99 percent unfrozen as of this outlook, has open water later into December. 50 additional years with this trend will have a dramatic impact on the personality and climatology of our winters in particular. I hear the skeptics refer to some obscure prediction made a quarter century ago about ice in the arctic and how it was predicted to be ice-free by now. I never saw such predictions at the time, but the changes that have occurred have been dramatic enough and ultimately will lead to an ice-free arctic sometime before the next turn of the century or early in the next one. 

In the meantime ice and snow are building in the northern hemisphere in comparable fashion to what has taken place over the last 10 years and without El Nino to ravage the high latitudes, there should be a better expanse of arctic chill over Canada this year when compared to last. 

What is the weather telling us ? 

My atmospheric tells section is the part of the outlook where I go through the exercise of examining recent weather trends as a means of predicting the future. Undoubtedly there's been some distinctive traits to the recent weather conditions that will help guide us. 1) It has been persistently warm in Vermont. The last time we've had a below normal month was November of 2023, a year ago. The combined impact of the -PDO and climate change haven't helped in this regard but it would be hard to expect any change in this basic theme without help in the form of different forcing mechanisms in the Pacific . We are getting a bit of help from the neutralized ENSO and let's all hope it provides some material impact. 2) It's been very dry over the past 90 days. Southern New England had a historic flash flooding event back in August and Vermont had a similar such event in July. September, October and November have been extraordinarily dry and sunny most areas have not had an event with an inch or more of rain on a calendar day since August.

Digesting all this and comparing these recent observations to previous seasons points you to one similar year in particular - 1964. That autumn featured dry weather in New England, had a building weak La Nina and a negative PDO. Northern Vermont got sporadic bouts of extreme cold but was decidedly below normal on snowfall and Burlington, VT in particular saw one of the lowest seasonal snowfall totals of the last 100 years. Since MRG opened back in 1949, there's been two other bigger negative PDO spans and some of those winters had very good results for northern New England especially on the snowfall side. The last two winters, though certainly warmer than the 1950's or 1970's, saw respectable snowfall amounts, especially over the high country. The king of all negative PDO winters, 1955-1956 was a more respectable snow season and certainly a colder one winter overall.

The Outlook Summarized 

My outlook for upcoming winter shows considerable amount of respect for the near record autumn negative PDO values. I can conjure up some optimism on the snowfall side, and I'll conclude with that more upbeat sentiment, but I expect us to struggle sustaining colder weather in eastern North America. We will have to hope that the ENSO-neutral to weak La Nina setup can allow cold to encompass a greater expanse of southeast Canada and that some of this cold can continue to keep winter in place across northern Vermont even as areas farther south are struggling.  It's encouraging to see a looser Pacific jet stream set up in the medium range outlook and this should help get us closer to an opening in the near term, I just have concerns about whether such a pattern can sustain for more than 2 weeks. Over the course of the winter, temperatures are likely to be colder than what we experienced during the strong El Nino winter last year but should remain considerably above average. In t this case I would prognosticate 2-4 degrees F above this average over the 4 month stretch beginning in December. I am more optimistic on snowfall side, especially for the possibilities of an upside surprise. If I had to pick a range on snowfall I would choose the 150-175-inch sub-optimal total both recent and more distant -PDO winters have been more generous and I think another over-performance is very possible, especially relative to coastal areas. Lets hope the next few weeks get us off the ground figuratively and on the mountain literally. Enjoy the upcoming season !