Monday, December 23, 2024

All kinds of good news for skiers that includes both snow in the short term and intrigue around the New Year and beyond

It's been a warm year in Vermont. Not only has every month been above normal up until now, the winter of 2023-24 saw about one subzero morning. Temperatures early Monday, which are as low as -10 in some areas, are easily the coldest of the calendar year and the month has an outside chance of seeing the coldest average temperatures of the year, exceeding that of January which is a statistical rarity. I love a cold bluebird day with a low wind so I am a little bummed to seek clouds making a rapid eastward advance and spoil a portion of this. Still, we expect temperatures to moderate and reach the teens in spite of less sunshine and those clouds are poised to bring snow Monday evening into early Tuesday. We tend to do well on these type of events, even with a lack of moisture, and my expectation is for a fluffy, low density 4-7 inches of by mid morning Tuesday. 

The rest of the holiday week is expected to be dry and just like we had hoped, the lack of strong ambient flow combined with the low December sun angle will slow the temperature moderation even as arctic air makes its North American retreat. We can also expect decent amounts of sunshine along the relatively calm winds and temperatures should generally stay below freezing except for maybe an hour this coming Friday. Not bad considering much of central Canada, including areas deep in the remote north will see a round of thawing temperatures. 

This home plate umpire is giving the safe sign for the last full weekend of 2024 with some of the same themes from the holiday week, carrying over to the weekend. Temperatures will continue to moderate, very slowly with readings touching or exceeding the freezing mark only during the afternoons. An increase in cloudiness should keep Saturday night considerably milder than the 7 days prior to it. It's a close call as to whether or not precipitation makes it to Vermont by Sunday, but it seems unlikely to reach northern Vermont by the end of the ski day. Maybe instant replay can overturn my call in a few days but I like my odds and I certainly think temperatures will stay sub-40 through the 29th on the mountain, something I would not have set 3-5 days ago. 

As more model data continues to stream in, the notion we are destined to receive rain during this New Year's mild period no longer seems to be a certainty and a mild rain all rain event isn't even the most likely scenario anymore. Though the jet stream blocking and extreme relative warmth will continue in eastern Canada, storminess appears like it wants to undercut much of this blocking creating all kinds of intrigue around the New Year's holiday. Sure, some wet weather is possible, but if a large storm undergoes some sort of occlusion within our vicinity, which several models have indicated, significant snow totals are entirely possible and could quite possibly mark an epic start to 2025. This situation certainly has my attention and although temperatures still look mild relative to average, not all mild weather is created equal. 

Beyond holiday, the pattern appears to have much better cold weather support with split flow developing in the eastern Pacific, large amounts of ridging in western North America and arctic cold working its way back southward in North America. Though above average temperatures are likely to continue through January 5th, it's less likely that readings are above freezing on the mountain. After January 5th, temperatures could more closely resemble a typical January and may even drop below normal for the first full week of the month. 

Friday, December 20, 2024

3-6 inches of windblown snow accompany a cold Winter Solstice weekend followed by only slowly moderating temperatures Christmas week

One healthy band of snow managed to rotate through the Mad River Valley on Friday and intermittent light snow will accompany the gradual descent of temperature readings along with the strong winds through Saturday. Total snow accumulations will be enhanced by the unfrozen state of Lake Champlain and although the big storm and heavy snow won't materialize, a cold 3-6 wind blown inches will provide some powdery turns. The intermittent snow will taper off and give way to some clearing Saturday night and sunshine should then make a partial appearance on Sunday. The big story is the cold obvoiusly. Temperatures will be near 10 while the snow is falling on Saturday and will be accompanied by 30 mph wind gusts, which could be higher at the summits. Actual temperatures Sunday are expected to stagnate in the single numbers with a continuation of near 30 mph wind gusts in spite of sunshine. Please dress accordingly. 

Winds will taper off late Sunday and clear skies along with the snow cover will provide the support for subzero temperatures Monday morning. We still expect a bluebird day Monday or at least most of Monday with calm winds and readings climbing into the teens. 

We are still expecting a surge in the EPO index around the Christmas holiday forcing arctic air to make a northward retreat. As mentioned in the last update, New England and Vermont in particular seem well positioned for a very slow moderation in temperatures throughout the holiday week. Additionally, a disturbance riding along the slowly eastward moving warmer temperatures will be the catalyst for a period of light snow Monday night into Christmas Eve. We appear to be in line for a few inches though we should expect some final alterations in these expectations over the coming days. Sunshine could make a nice appearance on Christmas Day and on the 26th. After that, an extended period of cloudiness which often accompanies a gradual push toward milder temperatures. Overall, none of these milder temperatures appear to be too much of a problem through the 27th with overnight readings remaining below freezing and daytime temperatures climbing beyond the freezing mark for a few hours late in the week. Moreover, Christmas week will feature no rain or mixed precipitation.

A massive blob of anomalous warmth across eastern Canada stands out like a sore thumb on the ensemble maps for the last full weekend of the 2024. In spite of this, there appears to be a way through this calamity and into 2025 which is starting to look very interesting, mostly because of potential storminess and more supportive temperatures. The days leading up to New Year's Day are the most challenging however since no fresh supply of cold exists within thousands of miles of us. A way through is contingent on the low sun angle of late December, minimal ambient flow that is not south or southwesterly and somehow avoiding potential rainfall. The operational simulations are going to be noisy out this far but it's encouraging that a few of them have indicated this possibility. Other simulations have shown some potential rainfall. The turn to colder weather and a higher probability of snow would then arrive on or before the first full weekend of 2025.

Wednesday, December 18, 2024

4-7 Wednesday night, some cold, light windblown snow Saturday and a slower temperature moderation Christmas week

Our round of new snow Wednesday night is on track and will mark the beginning of a nice stretch of pre-holiday wintry weather in northern Vermont. I had hoped that the responsible wave of low pressure would achieve a bit more legitimacy as it tracks over Cape Cod very early Thursday, but 1014 mb might be about all we can muster. The flat wave is still good enough to produce a period of wet snow beginning around 5-6 pm Wednesday evening and persisting for several hours. As expected, snow showers are expected in the aftermath although most of those will occur in the early morning and we should experience some clearing during the ski day Thursday. Accumulations get downgraded to the 4-7 inch category. Temperatures are still expected to drop enough by early Thursday to dry out the snow with readings on the mountain hovering near 20 and high 20's in valley locations. 

Models are telling me Friday is full of clouds with temperatures mostly in the teens. In the morning most of the clouds and some of the associated light snow will be over Michigan and rival state Ohio and my thinking is this will help induce a period of morning sunshine over us. Clouds, when they do arrive, will be a later day thing as the aforementioned clipper tries to merge with energy offshore Friday night. Right now, this merging is expected to take place too far east for heavy snow in Vermont or almost anywhere along the northeast coast. Coastal locations could still get a snow event of sorts but our snow will be generally light with accumulations in the windblown 1-4 inch category. The wind is a bigger story Saturday. When combined with actual temperatures of around 10 degrees, gusts over 30 mph will bring wind chills well below zero and easily make for the coldest ski day of the year. Wind chills are expected to be even worse Sunday in spite of more sunshine. Actual temperatures are expected to stay in the single numbers on the mountain and this means wind chill numbers lower than  20 below. 

Our winter solstice arctic outbreak is centered over New England and eastern Canada and is easily the coldest since late January of 2024. Temperatures might be even colder were it not for the Hudson Bay remaining more than 50 percent ice-free which marks the slowest pace of ice expansion since records of this began. Still, Monday January 23rd will be on old-fashion bluebird plate special with immaculate visibility, lower winds and temperatures climbing from subzero levels into the teens. We then have some good news for the duration of the Christmas holiday week with the temperature moderation appearing slower and a greater potential for some  light warm advection snowfall either Christmas Eve, Day or both. Though the rest of the country is expecting a more rapid rise in temperatures for the holiday as arctic air is expected to retreat in North America, New England seems well positioned to make the best final stand. High pressure is expected to remain situated to over the maritime region of Canada and December's low sun angle combined with an extended stretch of northeast flow, if that indeed prevails, will prevent excessive temperatures from making an assault on our ski country through December 27th.

Without a fresh available supply of colder air, there's some reason for concern as the New Year approaches and the threat of a more organized system and precipitation increases. The risk of any heavy precipitation appears low until the last full weekend of the month and then who knows. The coldest arctic air will remain bottled up into early 2025 as well but the outlook during the first full week of the new year has also shifted cooler as more ridging is now indicated in western North America. In early January, we have the climatological cushion of the coldest month of the year and a storm in the right place without the power of the polar jet can be the right ingredients for something interesting.

Monday, December 16, 2024

6-10 inches of new snow Wednesday night into Thurday and a milder outlook Christmas to New Year's

 The outlook continues to evolve for the home stretch of 2024 including the busy holiday period and there are some significant updates to the shorter term weather picture as well. Though it is amazing the progress that numerical weather prediction (modeling) has made during my professional life, stuff always seems to find a way to defy expectation. 

The cold rain Monday night shouldn't come as any surprise. Less than a quarter inch of this is expected and it should all be over by daybreak Tuesday. Daytime temperatures on Tuesday are the bigger story since we have a torchy dry westerly wind accompanied by some breaks of sunshine. This will boost temperatures to the highest levels of the month with close to 50-degree readings in valley locations and closer to 40 up on the mountain. Wednesday's temperatures are also expected to be mild but with less wind and ultimately more cloudiness 

Wednesday's late day clouds come out ahead of a nice midweek dose of snow. It will be a warmer event with temperatures within a few degrees of the freezing mark while the snow is falling. It all begins around 7 pm Wednesday with snow showers continuing through Thursday morning. The wet snow Wednesday night will amount to 4-6 inches but readings are expected to turn colder by Thursday morning (with the additional snow showers adding 2-4, supplying skiers with a well-deserved powder day. Northern Vermont is the place to be for this event as southern Vermont is expected to receive more ice and rain and is not positioned well for Thursday's snow showers. 

The solstice period defined by Friday December 20th to Monday December 23rd is very likely going to be the coldest period of the month.  Expect readings to stay below 20 on the mountain during most of this 96-hour stretch. The snow/storm potential is still there for Saturday though it does seem like the weaker storm Wednesday has helped to realign the storm track further southeast for the weekend. Energy and some light snow from the clipper is expected to be somewhere in the Ohio Valley on Friday and will be seeking fuel and support from any energy along the Atlantic coastline. The southeast shift of any such interaction is making it more unlikely that northern Vermont sees significant snow from this though a few of the many simulations over the past 24 hours still suggest its possible. What seems more likely right now is for the aforementioned cold and some accompanying snow showers Saturday followed by cold bluebird weather Sunday into Monday. 

The period running from Christmas Eve to New Year's Day continues to look warmer,the intensity of which comes as a surprise though some sort of Christmas thaw has been almost as certain in Vermont as the sun rising in the east over the past decade. Our one exception seems to be 2017-18 which was brutally cold. I was more surprised by the culprit for all this as it seems the jet in the Pacific will become rather intense in the days before Christmas, forcing arctic air into retreat mode. Though other teleconnection indicators continue to be mixed, the arctic retreat is legit and we can expect moderating temperatures by Christmas Eve and perhaps our first taste of above freezing temperatures on Christmas Day. For now, it continues to appear dry as this moderation is occurring without significant rain or mixed precipitation in the forecast picture until the last full weekend of the month. New Year's remains far enough out on the timeline for additional changes and hopefully a shift to more mitigated warmup. 

As we pass the 75th anniversary of Mad River Glen, it dawned on me how much pop culture has changed over that span of time, specifically music, my other passion. Out of respect for this, and hopefully as a pleasant distraction from a holiday thaw or anything else going on in the world, expect to see some music show up in the threads feed and on the blog. Each year of Mad River Glen's existence will see respect get paid to a different musician. That's 75 different musicians in 75 years and a challenge to come up with one good one for each year that was relevant to the year. It will be a fun exercise for me and hopefully an enjoyable listen should you partake in any of this journey.

Friday, December 13, 2024

Some snow potential emerging near the winter solstice while the outlook turns slightly milder around Christmas and beyond

With cold weather having returned to northern New England, we play the familiar game of searching in the outlook for our next chance at new natural snow. Looks like we will at least have one solid chance prior to Christmas. In spite of the recent rain, it's not been an especially bad start to December. Temperatures on the mountain are averaging in the low 20's with much of the fallen snow compressed into an icy base layer of concrete. Dust on crust. 

It was both a dry and extraordinarily sunny autumn period throughout New England, but our darkest month of  the year has seen clouds and a lot of precipitation so far. Friday featured some sunshine and this will be followed by two outstanding bluebird days with minimal wind. Saturday is the colder version with readings near 20 and Sunday is the more comfortable version with readings climbing to 30. The clear sky and tranquil winds will help bring many parts of Vermont below zero Sunday morning. 

Clouds are likely to return for Monday December 16th but the latest indication is that the warm advection snow, ice and rain stays to our south during the day. By Monday night light precipitation is expected to arrive as ice or rain and this could end as some wet snow on the mountains on Tuesday. Once again, temperatures are likely to stay in the 30's as the precipitation is falling and the mildest period in the week is likely Tuesday afternoon after the precipitation ends. 

The end of next week is beginning to look very interesting as there appears to be a building consensus for a big jet amplification. How this evolves in the form of specifics is very much a question as a series of jet impulses could have some impact on our weather. The one I have a particular eye on precedes the strongest surge of arctic chill so far this season and will rotate through the Great Lakes Friday. It has the potential for some constructive interaction with a weak low pressure area near the eastern seaboard with the end result being a material snow event somewhere in the northeast, most likely interior areas. Very cold weather and at least some snow showers is a minimal likely result of all this on Saturday (winter solstice day), with bitterly cold air and more snow showers lingering for Sunday. 

The previous paragraph summarizes much of the good news in this update. The more troubling part of the outlook involves the actual Christmas holiday and the immediate days after which do appear to be milder vs my earlier expectations. Though we do have continued support from the EPO, arctic air is expected to retreat somewhat over central and western Canada and the partially unfrozen Hudson Bay will make it more challenging to retain the existing cold in eastern Canada. For now, I would be inclined to favor only slightly above average temperatures and there are no glaring indications of wet weather .If we manage to lay down some significant snow next weekend (still a question), the holiday period could be a pretty good one relative to recent seasons.

Wednesday, December 11, 2024

Patience is required for help on new snow though pattern for the holidays continues to look encouraging

It was a soggy day, very much as expected across the mountains of northern Vermont. Temperatures however, remained in the 30's, defying expectations from a few days ago of a big spike and a bigger melt-off. This is important since the colder temperatures will preserve both some of the recent snowfall and will not put to waste all the snowmaking efforts from the nearly 2 weeks of sub-freezing temperatures. I remain cautiously optimistic on the outlook through the end of 2024 and perhaps even a step above "cautiously" as of Wednesday afternoon. We have the weather pattern aligned enough to support what could be the coldest December month since 2017. That said, we will have to be patient for our next chance at natural snow. We can expect a little taste here and there but still have another day of milder temperatures to endure (after today). 

Blustery winds will whip 20-30 degree temperatures back into the region by Thursday morning. The heavy rain will end as snow Wednesday night and we can expect light snow showers and flurries during the day Thursday, but the westerly flow is not an especially moist one for us and the heavier snow showers are more likely north of Stowe. Expect readings to fall not far from 10 degrees Friday morning and struggle to 20 Friday though with lots of December sunshine and excellent visibility. More blue skies can be expected Saturday, a comfortable day thanks to calmer winds and near 30-degree afternoon temperatures following a chilly start. 

The period beginning Sunday and ending Tuesday has been targeted by the various longer ensembles as a potential thaw or mild weather for awhile now. The warmth doesn't appear excessive and Sunday's increase in clouds underneath a surface wedge ridge are expected to help keep readings in check. Above freezing temps and some light mixed precipitation or rain appear pegged for Tuesday, December 17th before colder weather reestablishes a presence in New England. It's not a great outlook next week, but this could have easily been worse. Furthermore, longer range ensembles are providing us with our first hints of what could be our next significant snow either around or just before this year's winter solstice. 

This is underscoring a key point at the end of the last update about the pattern fundamentals for the rest of 2024. I really like the jet stream action in the Pacific and been pleasantly surprised that we might very well see this regime reemerge around the holiday. A lot of unsettled weather is indicated in the mid-latitude Pacific and the easiest way I can describe that is to call it an evil empire inversion. A natural result of this, among a few others is for some ridging to develop in western North America, providing us with our mechanism for a colder flow of weather. At face value, ensembles show normal temperatures across New England Christmas week. If we manage to split the flow, with jet energy in the Pacific undercutting that ridge in western North America, we can spin ourselves up a storm prior to the start of 2025.


Monday, December 9, 2024

Some snow Monday night is followed by a heavy rain event Wednesday

Mad River Glen has been on a roll, scoring a few inches of snow on nearly a daily basis over the past 5 days. This stretch of weather gets capped off with a final few inches of snow, all coming in a span of a few hours Monday evening. Even as warm air encompasses much of the eastern Great Lakes region, sub-freezing temperatures will remain entrenched across northern Vermont through early Tuesday. The snow Monday evening is of the front-end thump variety, as a wave of low pressure, passing to the region's south, marks the advance of the milder temperatures with an accompanying area of precipitation. Snowfall totals will be in the familiar 2-4 inch range and though it might fall as powdery snow, Tuesday's near freezing temperatures will make this consistency a little wetter. Much of Tuesday is precipitation free, but the mid-level temperature environment is expected to warm considerably even as surface temperatures hover around the freezing mark. By the end of the day, a stronger area of low pressure will organize over the southeastern United States and as this strengthening storm travels northward, much of the cold will  have been scoured out of interior New England. 

December has always been a tricky month for winter weather in New England. Even with favorable weather pattern, the proximity of all that relative Atlantic Ocean warmth leaves the region so vulnerable to the rogue inland runner and a big temperature surge. Such is very much the case with the rain event set to smack us in the face on Wednesday. The track of this storm isn't even that bad with the current expectation having the primary low track very close to us Wednesday evening. The lastest Euro, released right at the time of this update has the track of the low east of us over New Hampshire which would be good enough for a colder storm and some snow on the back end, yet mostly we would still be wet. The low pressure center in question begins to take shape across over the southeast early Tuesday and strengthens quickly over the Ohio Valley, continuing to intensify on its track toward northern New England. The fact that this storm will have not reached maturation upon its arrival opens the door for the northward push of low and mid level tropospheric warmth. Light rain or freezing rain in some areas begins Tuesday night and becomes a steadier and then heavier rain on Wednesday with temperatures gradually warming toward 40 degrees. Depending on the eventual track of the low, there is the potential for a brief but intense temperature spike for a few hours Wednesday evening. We might avoid this if the low pressure area tracks over New Hampshire, but either way, we won't avoid the heavy rain which will amount to well over an inch and then change to snow early Thursday before ending. Colder weather appears more intense Thursday and Friday with readings in the 20's on the former (with gusty winds) and perhaps only in the teens during the latter. Single digit readings are possible during each of the upcoming weekend mornings though wind is expected to subside and sunshine is expected for at least the Saturday portion. 

There is a nice looking cold air damming signature beginning to show its face on model simulations Sunday and this does indicate the possibility for an east coast winter storm. Whether or not the impact of such an event could reach far enough into northern Vermont is a tough question. I would call it unlikely right now but stay tuned. 

The longer range outlook which includes both next week and the following week continue to improve. The general consensus continues to point toward a milder period early next week but this milder weather has looked considerably less intense over time and there are no signs of rain of any significance. Multiple ensembles show colder air making a return late next week and likely consuming the region for solstice weekend. Though the ensembles aren't indicating a strong signal one way or another for Christmas week, I am very encouraged with the EPO which is again expected to turn very negative in two weeks time. This combined with a mildly negative AO favors colder and snowier conditions in New England. We've had the misfortune of many rainy Christmas weeks over the past several years. To say we are due for something better would be an understatement !