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Friday, December 31, 2021

Change back to snow and to winter comes Sunday with storm potential on Jan 6-7

As of late December, La Nina has strengthened slightly and is currently edging out last year's version by a tenth of a degree C. Measured in terms of weather pattern behavior however, this year's version appears more amplified and has had a very negative impact on winter weather on the east coast, especially from the Mid-Atlantic states southward. The southern Appalachians might as well be a tropical destination this past month as temperatures have hardly been sub-freezing and dewpoints have recently soared to near 60-degrees with accompanying heavy rain and thunderstorms. La Nina has always been a mixed bag in Vermont. Though we typically perform way better than the areas mentioned above, we have also experienced a few clunkers such as 1988-89 and 2011-2012. Though we appear to be heading toward another "clunker", the weather pattern does appear favorable for a half way decent stretch of winter in Vermont through about the first half of January. This is a critical stretch for us since we have some jet stream blocking in the Arctic and have managed to tame the Pacific jet stream for a time. I certainly don't expect these conditions to persist indefinitely this year and we thus need to make something happen and soon. 

Not much good will come from our New Year's weekend weather situation but there are worse results than this one. Most of the wet weather from multiple waves of low pressure will pass to our south and New Year's Day will feature just some spotty light rain or drizzle with temperatures hovering just above the freezing mark across much of the northern Vermont high country. A push of colder temperatures will reach the MRV early Sunday as another in a series of low pressure waves passes to our south. Light rain will become freezing rain and sleet for a time and eventually turn to snow sometime during the ski day. 1-3 inches is likely from all this but there continues to be the risk we get screwed entirely. 

Portions of the coastal Mid-Atlantic and SE Mass, which have seen little to no winter so far, might receive a bit of snowfall fall from a rapidly strengthening low pressure center off the coast. This is a big whiff for Vermont, but big offshore storms are the best way to get the sun out and visibility improved in Vermont during the winter months and we should see a healthy dose of sunshine to go along with chilly 15-20 degree temperatures. Sunshine will be back for part of Tuesday and will help to warm readings back into the 20's before warm advection clouds advance back into the region. The window for milder potentially above-freezing temperatures appears short and confined mostly to valley locations on Wednesday. Even better is the potential for a big winter storm late Thursday Jan 6th into Friday the 7th. It's a delicate situation involving arctic air spilling south and a rapidly amplifying jet stream. There's also some lingering mild air along the immediate coastline as another potential monkey wrench. Still, the ensembles are showing a nice consensus for a decent event and interior New England appears to be the best location for results. Operational models have and will continue to be noisy for the next few days but more clarity should arrive within a few days. It's the best chance we've had all winter for a decent storm but it remains a "chance" for now and not yet likely. 

Whatever happens Thursday into Friday, the storm and the associated polar jet amplification sets the stage for a cold and mostly dry weekend with readings falling to near zero Friday and struggling to reach 10 on the mountain Saturday January 8th. Reading should moderate somewhat by Sunday the 9th. 

The marginally favorable pattern described in the first paragraph appears somewhat encouraging for Vermont but does not appear capable of sustaining arctic cold in the Ohio Valley or Mid-Atlantic states. We can put a positive spin on this situation by suggesting that an overwhelmingly cold pattern is often not a particularly snowy one in Vermont in January. The widespread area of cold across eastern North America is expected to quickly give way to normal and even above normal temperatures in some areas to our south. Meanwhile the center of the polar vortex will reposition itself in eastern Canada, keeping much of New England and especially Vermont within Vermont's reach. We should thus see a reinforcing shot of winter chill around January 10th and 11th with additional chances at least lighter snowfall throughout that 2nd full week of January. 

Wednesday, December 29, 2021

Weekend weather is mostly wet with only a chance it ends as snow late Sunday but early January pattern appears decent overall

The weather we have seen during this back half of December 2021 can be described as La Nina to the extreme. Cold, unsettled weather over parts of the west coast with snow in the mountains, extremely mild weather along the Gulf Coast and southeast U.S. and lots of cloudiness and marginal precipitation events in the northeast. Though we may have successfully retained a little sense of winter in northern Vermont, it hasn't been much of a consolation prize especially considering recent underperformance and another wet weather event on a holiday weekend. This is classic La Nina however and if we can just move the battle lines 100-200 miles to the south, our performance would improve dramatically. 

Much of the southeast is finishing the warmest December on record and the ridge responsible for much of this weather continues to push weak, disorganized surface features in our general direction. These have been difficult to predict and have been under-delivering as I mentioned above.  Some occasional light snow is still expected both Thursday and Thursday night but accumulations appear insignificant. Meanwhile the weekend weather event will begin to take shape as a stretched area of low pressure along the already established southwest to northeast temperature boundary. The first area of low pressure will approach New Years Eve and we will thus see another day of cloudiness and some light afternoon/evening snow eventually giving way to some freezing rain or drizzle by early New Years Day. This initial wave is weaker but is nonetheless critical since it will ultimately track well into Quebec and allow milder air to infiltrate the critical levels of our lower troposphere ahead of the primary weather producing storm. 

I had hoped that some low level cold could make a push southward on New Years Day keeping sleet and snow in our equation for the weekend. We've gotten some good news as the track of this stronger area of low pressure appears farther south, perhaps tracking right through the heart of central New England but the cold ingredients are behind the system making snow a difficult ask. Temperatures on New Years Day are likely to hang out near or just above the freezing mark though it does look like we will keep much of the ski day dry though it will stay very overcast. Rain and a few pockets of freezing rain are likely to arrive during the evening New Years Day (Saturday) and continue into the overnight. Perhaps we can keep the rain on the lighter side and minimize the amount of total wet weather but whatever falls Saturday night is not likely to be good. All might not be lost with this storm however. Energy with this storm is eventually expected to consolidate around the trailing area of low pressure and if that passes to our southeast, another area of precipitation later Sunday into Sunday night might still start wet but finish as a period of decent snowfall before Monday morning. We need another few rounds of model data to sort through some of those details. 

We do know that the first full work day of 2022 (Monday, Jan 3) will feature wintry temperatures with readings generally holding in the teens during the day and falling into the single numbers during the overnight. Flurries and snow showers are likely during the day Monday but we should also see some intervals of sunshine and we haven't seen much of that this week and don't expect any this weekend. More sunshine and even better visibility is then expected to Tuesday accompanying some very typical January chill. The cold weather is likely to continue into Wednesday before temperatures moderate ahead of another system likely to advance into the Great Lakes. The late in the week period between January 6th-7th again appears marginal with milder air attempting to push northward into New England. We could get a better result ahead of the Jan 8-9 weekend but could also see another mixed bag of weather. 

On the state of the weather pattern more generally, there are some aspects you have to like. The jet stream in the Pacific through much of early January appears relatively loose and combine that with the blocking structure in the Chukchi Sea region of the arctic and cold air will assuredly push southward and impact much of the United States, especially the northern half of the country. Along the east coast, it's just a question of warding off the negative effects of the pesky Nina southeast ridge. I would expect at least some snow to accompany the inbound arctic air around the weekend of January 8-9 (perhaps as early as January 7) and this will be followed by several days of below normal temperatures. Interestingly, ensembles indicate that the southward moving polar vortex will bounce (for lack of a better word) off the southeast ridge and eventually land in eastern Canada. This would place Vermont in a pretty good spot for winter weather in the middle part of January but the wait has been long and agitation is understandably high (I know it is for me). 



Monday, December 27, 2021

Clouds, light snow and some mixed precipitation dominate the outlook for the rest of this week while a bigger storm brings snow potential for the New Years weekend

I endured my first significant bust of the season with a Christmas Storm that featured way more ice and way too little snow relative to my outlook and more importantly to our collective approval. This weather pattern is not providing any time to wallow in forecast sorrows as a very active weather is expected over the next week. The jet stream ridge in the southeastern U.S. is proving durable, even when faced with increased amounts of polar energy and we thus have a situation where we will be in the path of many weather systems. We will undoubtedly get some snow in this setup but also be faced with more marginal situations comprised of mid-level mild intrusions leading to more sleet and ice. 

We have enough cold air in place Monday night to support a period of light snow and 1-3 inches, mostly in the pre-dawn hours Tuesday. Clouds and some of that light snow will continue into early Tuesday but I expect visibility to improve some as the day progresses and as winds shift to a more westerly direction and a weakened area of high pressure builds in from the north. Fair weather breaks will be very short-lived in this regime and especially this week and any clearing late Tuesday will be followed by increasing clouds early Wednesday in advance of a weak area of low pressure approaching from the west. We can expect mostly clouds, sub-freezing temperatures and calm winds Wednesday with precipitation holding off until Wednesday night. Another marginal precipitation situation awaits us Wednesday night into Thursday when, if we were to see heavy enough precipitation, we could see a decent period of snow. At least right now, precipitation is indicated to be fairly light however opening the door for another "mixed precipitation" situation. Temperature profiles do appear a little colder than they did over Christmas but as I mentioned, precipitation appears lighter and I would guess that we see a little bit of everything between late Wednesday night and early Thursday amounting to 1 or 2 inches of an icy conglomerate. 

The most significant east coast weather system we have seen in a while is now expected to impact the region New Years Day and into January 2nd (which makes up the entirety of New Years weekend).  Though we are still awaiting to unravel some critical details, there could be multiple areas of low pressure involved and a variety of precipitation types though I am increasingly confident we can keep it all frozen in our part of Vermont. A modified area of arctic cold is expected to fight its way into interior New England on New Years eve following Thursday's precipitation and provide us with decent enough area of low level cold to support a solid front-end thump of snow on New Years Day. Much will hinge on critical details as I mentioned and although an epic 1-2 footer is unlikely with this event based on the current projected storm track, 6-12 powdery inches takes up some decent space in the possibility spectrum. This would be followed by the potential for some mixed precipitation Saturday night (still Jan 1) and into Sunday followed by the potential for some additional snow late Sunday into early Monday. The strongest area of cold this season should then makes its way into New England for January 3rd and keep us very chilly though at least the 5th. 

As I mentioned a few days ago, the emergence of the Chukchi Sea block on all of the ensemble simulations is one of the more noteworthy jet stream features on the early January 2022 weather map. It is almost a certainty that intense arctic air will plunge southward in North America but the Chukchi Sea is pretty good distance from eastern North America even when measuring in jet stream long waves. New England will again not be the focal point for the extreme cold and this type of setup will continue to allow the ridge in the southeastern U.S. to flourish and leave Vermont in the continued battleground area of weather. After a few days of cold weather between January 3-5, we might face another marginal scenario where a storm system is attempting to force mild air into New England around January 6-7 and this would be followed by another round of colder arctic air. I fully expect our snow depth to be in a much better situation than it is now in two weeks time but it will be a bumpy ride and there is no clear evidence of a home-run event as of now. 



Friday, December 24, 2021

Snow, some freezing rain/drizzle expected for Christmas Day and a more promising outlook around New Year's

 There's a lot to unpack in this rapidly Evolving weather situation across northern Vermont and yes I capitalized "Evolving" on purpose for emphasis. It's about to get very cold in the Pacific Northwest, a ton of snow is falling around Lake Tahoe and our friends in Aspen got a little taste of what it's like in a typical east coast ski season - it rained !  A rare occurrence in Colorado above 8000 feet, but it rained for several hours Wednesday evening and night and although it is expected to snow Christmas Eve, wet weather is not something that ski town is used to in any winter month. The system responsible for Colorado's weather will move east quickly and bring Vermont its share of weather on Christmas Day. The details continue to change very rapidly. 

 First of all relates to the timing. The whole event was a question mark a few days ago and was initially pegged as a late Christmas Day, early on the 26th light snow situation.   Precipitation is now expected by dawn on Christmas Day. This is a very disorganized storm and is moving quickly but is expected to get an infusion of moisture from the Gulf of Mexico. Additionally there are healthy low and mid level frontogenetics in place from the strongest area of arctic cold we have seen this season (temps fell close to zero early Xmas Eve in northern VT). In spite of the strong area of surface cold, milder mid level air is expected to chip away and push readings  into the marginal category at around 6000 feet even as it remains sub-freezing closer to our surface. What does this all mean ? Temperatures are close enough to freezing, where it counts, for snow to fall so long as precipitation is heavy enough. When precipitation is lighter, freezing rain or drizzle is possible. Based on some experience I've had with these types of setups, I am going to predict a decent period of snow Christmas morning resulting in a few inches, some light freezing rain or drizzle in the afternoon followed by another period of light snow Christmas night into early Sunday morning the 26th. I think it all totals to about 3-6 conglomeration and I am hopeful that the final inch or two is off the fluffy snow variety. A gentlemen on twitter asked me about the differences between Champlain Valley weather and MRV high country weather and this is one of those instances where we can expect some huge differences. Burlington will get light easterly downsloping winds hurting their ability retain the necessary amounts of low level cold to support snow. Their low elevation will also hold down total precipitation amounts and they will likely struggle to get an inch. Rutland will perform even worse for the same reasons in addition to the fact that they are positioned closer the milder mid-level air. 

We are likely to see more of these marginal situations in the next two weeks with arctic air on the playing field but the southeast U.S. jet stream ridge maintaining a presence and even occasionally surging northward in our direction. Temperatures, especially across the high country, appear to be mostly sub-freezing but it won't guarantee we can keep all precipitation in the form of snow. The next chance for such event appears to be around Tuesday the 28th or Wednesday the 29th with temperatures at critical levels again appearing marginal and varying precipitation types possible. 

There is some decidedly good news involving New Years which appears both colder and potentially snowy across northern Vermont. Models are having a very difficult time dealing with all the fast moving systems and the specifics are therefore very blurry right now but the threat of a thaw appears reduced while the chances for accumulating snow increased in the period between December 31 and January 2. Even with the continued presence of the southeast U.S. ridge the longer range outlook continues to show a decent coverage of arctic air especially over central Canada. Two of the major 3 ensemble packages now indicate a blocking feature in the Chukchi Sea. If this does indeed occur, we will see some very intense arctic chill make a southward push into the U.S. in early January though the focus of this would likely be west of New England. It will mean an interesting start to 2022 to say the least with arctic air likely competing with the southeast U.S. ridge and placing us in the pathway for multiple storms with a variety of outcomes possible.

Wednesday, December 22, 2021

Uncertainty remains regarding specifics but snowfall over the next 8 days looks better beginning early Christmas Eve

 The White Mountains got a bit of light snow Wednesday morning and parts of interior Maine saw a decent snow event from the mostly offshore storm conglomeration. Vermont was in the unlucky zone this time and aside from snow showers on Wednesday/evening night, our high country under-performed. Our natural snow prospects are looking up generally with several chances emerging or coming into focus beginning early on Christmas Eve. We have a concern around the New Years holiday but I would be inclined to take the "over" on a foot of new snow before Near Years 2022 and the pattern looks favorable for more in the first week of 2022. 

The Hudson Bay is now 80 percent frozen and this is allowing stronger arctic air to infiltrate eastern Canada. Some of that chill will successfully make inroads into northern Vermont Wednesday night into early Thursday and as a result, we can expect the coldest day of the season so far with temperatures holding in the teens across the high country and struggling to 20 in the Valley. Clouds and an area of light snow are expected early on Christmas Eve. The best chance for 2-4 inches appears to be over the Berkshires or southern Vermont but this zone of snowfall has looked better and better over time and 1-3 inches looks likely the MRV as opposed to just possible with all of this coming before the ski day. Of even more interest is what appears to be a healthier area of moisture associated with an approaching storm system late on Christmas Day into Sunday the 26th. Models are having trouble establishing a clear consensus on the outcome here but the American model has, for several runs, indicated a significant snowfall for much of northern Vermont. I want to be optimistic but taken in the aggregate, a significant storm of over 10 inches remains just possible but a light snowfall late on Christmas Day into early on the 26th of at least 3 inches appears likely. The forecast is likely to evolve a bit so stay tuned. 

Interestingly, the models not on board with a storm on the 25th/26th are on board with snowfall Monday/Tuesday the 27th and 28th. So it appears to be a situation where the various forecast simulations are having trouble resolving the complicated interaction of jet stream shortwaves and areas of moisture and surface features. In spite of this uncertainty however, we have the right ingredients for snowfall through December 30th and are in a good spot for snow in a fairly wide range of scenarios. Just a matter of determining the where and the when. 

Where I have some concern is the period around New Years. The big picture jet stream view has a blocking feature in the Hudson Straight around this time while a ridge in the southeast United States experiences from temporary strengthening. I can recall how the Christmas 2020 forecast evolved into a debauchery and will note some similarities. We don't want any storm getting sucked into central Canada to the west of that block and would much prefer a storm that would tunnel through all of that and allow cold air to remain entrenched over Vermont. Ensemble data would seem to suggest a latter scenario for now but I am little nervous. 

Meanwhile the bitterly cold air over North America will maintain an intense focus on western Canada and portions of the Pacific Northwest both around and after Christmas. Most of the big weather headlines that are winter related will be focused on that region of North America but some of that cold is indicated to stretch eastward into early 2022 and impact parts of New England. If we can avoid a New Years thaw, we would be set up well for a productive start to 2022. Congratulations to all for rounding another Winter Solstice. We can never be too certain about weather conditions but we can say that the next 6 months will feature increasing amounts of light so enjoy !




Monday, December 20, 2021

Even as milder weather controls much of the eastern United States this Christmas, winter maintains a grip on Vermont with several chances for light snow in the coming week

A couple runs of the European Model was suggesting a widespread torch on Christmas Eve and Christmas Day over portions of the Plains, Midwest and Southeast. On the heels of the out of season weather last week and last years Christmas monsoon, this caused a bit of a stir in the social media weather back and forth. Though the weather has trended in the "not as cold" direction over Vermont, our outlook still appears pretty solid for winter weather through the holidays. Our biggest concern involves the track of a  potential weather system on December 28th, but taken at face value, sub freezing temperatures appear likely to hold their ground, especially above 2000, where most of us actually ski. 

A clipper system, well to our north will give us a distant hand wave but aside from some flurries or very light snow, we won't see much of anything. If you're desperately looking for that 1-3" then head toward the Canadian border but most of Vermont will just see intervals of clouds and sun on Tuesday with temperatures generally in the 20's. We have better chance of snow early on Wednesday when a strong sub-tropical system off the Atlantic coast begins to team with a stronger polar/pacific impulse. An area of snow will be expanding across eastern New York and interior New England and although the best area of snow clearly appears to be Maine, several hours of light snow is likely across the northern Vermont high country before dawn or at least before the ski day Wednesday. This appears to be a 1-3 situation but additional changes are possible. 

The cold weather will hold its ground across Vermont on Christmas Eve/Day but the milder air will make a big push northward and that process will create a zone of moisture and precipitation across the northeast. In Vermont most of that will fall as snow, so long as the moisture makes it far enough northward before decaying as it runs into dry airmass stationed to our north. The timing of all this appears to be either late on Christmas Eve or early Christmas Day and would amount to another light accumulation for the Christmas ski day if it happens. 

The big picture outlook has trended toward the less cold side. The main reason for this has to do with the bitterly cold air having a specific focus on western North America particularly western Canada. Meanwhile, a blocking ridge will migrate from central Greenland to the Hudson Strait well north of us. Oddly enough (or not so oddly), this pattern appears similar to the jet stream configuration that prevailed in the weeks following Christmas last year. Though much of the Vermont high country remained sub freezing throughout the period and even scored some decent snowfall, temperatures were not bitterly cold and continued to average above normal relative to climatology. 

As mentioned in the opening, there is evidence of another organized storm impacting our region around the 28th. We have what appears to be a soft area of cold weather dominating much of interior New England and eastern Canada around this time and although in the case of Vermont, milder air will make another run at the region, ensembles are suggesting that sub-freezing temperatures hold. This means that the forecast for the holiday week should consist of temperatures in the 20's and 30's for highs and mostly teens for lows. Chances for snow or wintry precipitation are on the aforementioned Tuesday the 28th and again closer to New Years.

Friday, December 17, 2021

6-12 for Saturday with a wintry holiday outlook remaining in place

Our reintroduction to winter on Saturday will be exciting with a beautiful powdery snowfall expected to begin around noon and continue at a slow but steady rate through the overnight and into very early Sunday. It is actually a very straight-forward forecast considering. I know some of the model output maps circulating around social media would indicate that southern Vermont is the best spot for this storm. Perhaps, but I would still prefer to be us. We will be in a colder spot with temperatures closer to 20 on the mountain and temperature profiles indicate no threat of mixing - just a cold powdery snow from start to finish with 1-3 inches late in the ski day Saturday and a storm total of 6-12 inches by the start of the ski day Sunday. Flurries will linger into Sunday but the daytime weather will feature some sunshine, blustery and cold conditions with temperatures around 20 degrees. 

We will have additional chances for snowfall late Monday into Monday night (very light) and again on Wednesday into Wednesday night the 23rd. The polar jet disturbance arriving on Wednesday may interact with a stronger sub-tropical feature off the Atlantic Coastline setting up an inverted trough situation and a decent area of snowfall somewhere across interior New England although it will take another day or two to figure out if 1) that actually happens 2) where that actually happens. We will successfully keep temperatures under the freezing mark for an extended stretch, beginning with Saturday's storm and lasting through Christmas; in fact, the actual Christmas holiday will likely feature the coldest weather of the season so far with the phased storm off shore opening the door for a stronger version of arctic air to enter our forecast picture. Having said this, any cold weather should remain in the garden variety category for Vermont with high temperatures in the teens and 20's. The much below normal cold should remain out in the Pacific Northwest for the time being. 

Some of the above dovetails rather nicely into the longer range outlook which continues to consist of winter-like temperatures of a more garden variety and certainly a few chances for snow between Christmas and New Years. The feature in the jet stream that will help keep New England on the more wintry side is a strong area of unsettled weather positioned south of Newfoundland, directly underneath a blocking feature over Greenland. Northwest flow in the jet stream (over us) is generally considered fair-weather flow but a weak ridge in the central United States will try and push storms up in our direction once or twice. We could also attain a bit of colder moisture from the Canadian Maritimes in this setup were we to miss out on a more organized weather system. The colder more wintry outlook remains in place through both holidays right now and certainly no repeat of last year's rainy Christmas debacle. Enjoy the powdery snow Saturday !


Wednesday, December 15, 2021

Mild stretch ends Friday with 6-12 powdery inches coming late Saturday and colder weather maintaining a grip on Vermong through Christmas

Parts of Nebraska and Iowa that are more used to seeing sub-zero temperatures this time of year are dealing with a massive severe weather outbreak from thunderstorms. Straight line winds of close to 100 and even tornadoes just add to what has been a historic December for weather more typical in April or May. Though we will avoid the thunderstorms on Thursday, we can expect some gusty winds to go along with the very mild 50-plus temperatures, especially during the afternoon and evening. 60-degree readings are certainly possible in valley locations but it will require a few hours of sunshine and that is not what data is indicating at this time.

Colder temperatures will very slowly seep back into Vermont Friday but we can still expect a very mild December day with readings generally above freezing with the exception of the highest summits. Fortunately this will be the last such day in a while with a new very improved regime set to take over, just in the nick of time for the holidays. Saturday's storm is a beauty. A fast moving open wave, so we won't see anything historic but the storm is strong enough and appears poised to track right through our powder alley - the southern New England coastline. Temperatures might be hovering in the high 20's Saturday morning, but will fall into the teens and low 20's once the snow begins around noon and continues into the overnight hours. By Sunday morning, much of northern Vermont can expect a powdery 4-8 inches with 6-12 over the high country. A very nice liftoff event even if it was delayed. 

I had my fears and doubts but it appears as if the cold will mostly win the battle for control of Vermont's weather following Saturday's storm and through Christmas Day. This is terrific news because the risk of another thaw or rain/ice type event was certainly lingering, but we can just push much of that to the south for now. It doesn't look like anything big will come together for Monday/Tuesday, the 21st and 22nd but a polar jet impulse has the capability of bringing both light snow Monday night followed by a reinforcement of colder temperatures for the middle of the week. There is an interesting sub-tropical feature that will be spinning its wheels along the Gulf Coast at this point and its interaction with the series of polar jet impulses remains a question. It may pass innocently offshore with a whimper late next week, but it could phase either slightly offshore or closer to the coastline with a stronger polar jet impulse poised to enter our forecast picture on the 23rd into Christmas Eve. Either way, it provides us with another opportunity for at least some light snow and a slight chance for something bigger. Temperatures on the mountain should remain below the freezing mark throughout next week and should top out in the 20's and 30's across the valley locations while falling into the single numbers and teens during the overnights.

Our new and improved weather pattern continues to look gradually better with each passing day. The bulk of the cold and storminess still appears focused on the Pacific Northwest around Christmas, but this area of cold appears to seek a broader, flatter influence over lower North America. It will essentially get squeezed, pinched and almost hyphenated over southern Canada and the northern third of the United States, lodged between two upper air ridges, one in the northern Pacific and another over Greenland. Barring a change, this should equate to some excellent results for Vermont with cold weather remaining in place or even intensifying and a storm track aimed south but not too far south of us. The southeast ridge appears weaker but it continues to lurk over the southern plains, This collection of features should produce a rather fast current of air over the United States and some storminess between the holidays. Just a massive improvement compared to how this all looked a week ago ! Fingers remain crossed.




Monday, December 13, 2021

Next week/holiday outlook continues to show improvement with new snow providing relief as early as Saturday !

The torchy pattern already underway will hit us with 3 big upper cuts. The first having already happened on Saturday with the rain and wind. The 2nd came Monday and was a rather tranquil spring-like Vermont day with plenty of afternoon sunshine and near 50-degree temperatures across low lying areas. The third will come Thursday and continue into Thursday night and will feature more wind, maybe some minimal sun Thursday afternoon and readings as high as 60 in some valley locations. The strong and balmy winds will continue through the Thursday overnight but we appear to be mostly done with the "R" word and the outlook beginning as early as this weekend continues to improve and the holiday period continues to look more and more wintry across interior New England. 

Two very important fundamental changes will be responsible for aforementioned improved outlook. Convective forcing in the south Pacific will continue to work at softening the jet stream and forcing much of the ridging closer to the Arctic. This along with the formation of a large ridge in the jet stream over Greenland will allow much of the arctic air over North America to make a southward push, even within a week ! We haven't eliminated all of our road blocks. The formidable ridge will get pushed southward across the eastern United States but will not be eliminated completely and thus the pattern will take on a classic La Nina look with cold and storminess focused on the west, mild weather confined to the southeast and winter assuming a tenuous grip on the Great Lakes and New England. I'll take tenuous over nothing and with that we can discuss our chances for snow. 

Our first chance comes Saturday in a classic, if you don't like the weather just wait a day - fashion. Temperatures on Friday will be very slow to chill and are unlikely to reach the freezing mark until Saturday when precipitation is set to arrive. We won't have any cold/dry air to work with in eastern Canada but we will have incoming cold behind this system and  this creates a scenario will temperatures will continue to fall late in the day Saturday allowing any mixed precipitation to turn to snow. We have two of the three major medium range computer simulations indicating this event and I am certainly at the point where I think it's more likely than not. What kind of event do I speak ? At least a few inches of snow followed by garden variety cold weather Sunday into Monday.

In addition to the event on Saturday, there are indications of another on Tuesday, the winter solstice and then another right around Christmas weekend. Most importantly (at least to my eyes) is this continued trend to place interior New England on the cold side of this Canadian cold vs southeast U.S. warmth battle. This alone substantially lowers the risk for any rain and above-freezing temperatures of any real significance.

Saturday, December 11, 2021

Though weather pattern flip is unlikely by the holiday, winter weather and snow is likely to make a return, at least in some form

 I can't provide any good news for the upcoming week except to reiterate what has already been discussed and amplify on a few themes. We can expect to see sunshine Monday, Tuesday, and parts of Wednesday and Thursday while most of our nights will stay sub-freezing. It will be mild Monday and then very mild late in the day Thursday, Thursday night and into Friday morning. Last I checked, it's pretty hard to blow a building down that hasn't even been built and I am of course speaking figuratively about our snowcover. If clouds do give way to sunshine and wind on Thursday, we could see temperatures approach 60 across low lying areas. If it stays cloudy, it will stay cooler much like it did Saturday but the mild air combined with wind will chew away at any existing snowcover man-made or not. Those snow-eating conditions will continue into Thursday night before cooler weather arrives during the day Friday. It's a very mild week overall but we've been anticipating this for a while and although a pattern flip still isn't imminent, the outlook continues to improve starting as early as the December 18th-19th weekend. 

There are a few important bullet points to keep in mind. 1) Climatology in late-December Vermont is quite different than early-December Vermont. Marginal patterns can be productive by late December. 2) The pattern doesn't look ideal but the weather pattern continues to look less and less unblocked by the winter solstice (sorry about the double negative there but trying to apply the most accurate adjectives). 3) The coldest weather in the northern hemisphere continues to be heavily focused on our continent, opening the door for arctic air to provide a much needed assist in this marginal overall weather pattern. 

The bottom line for the days leading up the holiday and beyond: The focus of the cold appears to be on western North America just as it did a few days ago but with the jet stream at high latitude looking more blocked, arctic air appears capable of being a significant player across northern Vermont. We will certainly need it given the continued presence of a ridge in the jet stream in the southeastern United States. The period beginning December 18th and extending through Christmas is likely to feature several chances for precipitation. Though we are unlikely to score victories for every potential event, we will be back in the game which is certainly a big improvement over the upcoming week where we will have "no game". Hopefully we all stayed dry today !

Thursday, December 9, 2021

A mostly mild outlook remains in place but I've seen worse !

 I want to start this post on a wintry theme. First, it is wintry thanks to the snow we received Wednesday evening and a couple of beautiful Lake Champlain enhanced snow showers that were nice to enough to present themselves to the Mad River Valley Thursday morning. More generally (and secondly), the region is on the far southern periphery of a very impressive polar vortex that impacted much of central and eastern Canada with severe early December cold. The expansive area of chill never really made a serious run at the United States but it did effectively eliminate all of the warm water in the Hudson Bay, which as of December 9th is a third frozen. Take a look !  

SST Animation

Arctic Ice Coverage - NATICE 

The upcoming forecast is not especially wintry but eliminating bad feedbacks mechanisms will hopefully pay dividends down the road. In the short term, we can expect to enjoy our wintry weather through Friday and perhaps pick up a little light snow from some rapidly northeastward moving warm advection moisture. That snow exit by early afternoon and we can expect temperatures to hover around the freezing mark through Friday night. Saturday still looks to be a torch. Mad River has indicated they want to open the practice slope on Saturday and we can expect low clouds in the morning to give way to a mild and windy afternoon with rain showers moving between 1 and 3 pm. Temperatures are likely to make it well into the 50's in the valley and at least approach 50 at the MRG base so snow conditions should soften accordingly.  It won't be as mild Sunday but it won't be cold either with temperatures hovering in the 30's. Expect both sub-freezing temperatures and wind above 2500 feet. 

The central third of the country appears to be ground zero for next week's mega torch. Mild temperatures will impact Vermont as well but as I mentioned a few days ago, we will mostly remain on the fair weather, front flank of the large jet stream ridge. This means we should see decent amounts of sunshine and it also means cooler Canadian air is likely to keep interior New England closer to normal compared with areas like Minnesota or Wisconsin. Temperatures are likely to climb into the 40's across low lying areas on Monday and might get as high as 50 very late in the week. Most of our nights will be sub-freezing however and the middle part of week will feature sunshine and readings in the thirties. I expect to see a bit of rain sometime late in the week but I've seen rainier and milder thaw's than this one. I like mild weather in the spring but I find record high temperatures in December to be rather soul crushing and I don't think we see those next week. 

There are also signs in the long range that the pattern fundamentals or teleconnection indices will be improving. The jet stream at high latitudes begins to look less unblocked and the AO index appears close to zero as we approach Christmas. All this said, the pattern still favors mild weather in New England through the Winter Solstice and beyond and even if effectively neutralize the AO and partially weaken a Pacific Jet stream, it will take a little while before we can start talking about a sustained stretch of winter weather and cold. I might add that the changes in the jet stream fundamentals actually favor a rather impressive out break of cold across the western North America. I expect some of our favorite ski areas out west to perform very well during this holiday period and into early 2022. 

I did notice that the Chrome internet browser is not letting users on to the blog while other browsers are indicating it is not secure. I will look into this and hopefully we can rectify quickly. 

Monday, December 6, 2021

The unfriendly December weather report

It's not a friendly update  in the shorter or longer range today and I think the best thing we can do  is simply establish that it should be a a month of low expectations and hopefully we can surprise to the upside from a low bar. Speaking frankly, we have a dreadful collection of teleconnection fundamentals while we continue to face warm ocean/lake water temperature feedbacks stemming from months of warm weather.  There are some in the weather forecasting community suggesting a return to colder/more wintry weather by Christmas and I will talk about that more in depth a few paragraph's down but personally I am pessimistic we will see any sustained stretch of wintry weather after December 10th until January '22. With colder temperatures close by in Canada, we could see multi-day stretches of cold weather and some snow but more generally speaking, this will be a challenging last three week of December, there's just no getting around it. 

Regarding the midweek threat of snow, it has not vanished entirely but almost entirely . The system currently centered near Grand Teton National Park is simply not very robust, and is not expected to be as it migrates into the central Plains Tuesday. A wave of low pressure is still expected to evolve into a more organized storm along the eastern seaboard by early Wednesday but without the help of a more potent Midwest weather system, it is difficult to imagine a big east coast weather producing system evolving from this and models are not suggesting there is one. In other words, we need more than just a "northward shift" we need a stronger storm. Light snow can still be expected Wednesday, enough to whiten the ground with 1-3 inches, but a big storm has gotten more and more unlikely. After the thaw on Monday we can expect sub-freezing temperatures through Friday with some sunshine on Tuesday, some more on Thursday while Wednesday features the aforementioned light snow. More light snow is possible very early Friday ahead of the push of much milder temperatures. 

This first push warmer weather Saturday looks especially ferocious and we can be glad about not having any deep early season snow because most of that would get wiped out by the combination of near 60-degree temperatures, wind and a period of rain. There are some question marks relating to a wave of low pressure that could become a well organized east coast area of low pressure. This storm will have a weakening area of cold to work with but there are scenarios that could include a mild rain to snow situation on Sunday. Both the European and American models have suggested such at various times but data is not illustrating any confidence inspiring consistency that such a scenario will occur. Regardless, we will get a return to colder weather for a day or two beginning Sunday before again facing the music of a very bad weather pattern. 

 More specifically on next week, the large warm weather producing jet stream ridge is expected to set up over the middle of the United States placing New England in the warm but front flank part of this expansive weather feature. This does give us the silver lining of both pleasant weather and a continuation of mostly sub-freezing nights which enable snow making operations to continue. I've seen a few simulations suggesting an area of more legitimate cold could save interior New England from a multi-day thaw. This is possible but at the very least I would expect a few above-freezing days and certainly not a lot of natural snowfall if any. 

Getting back to the longer range/holiday speculation talk, I've seen some speculation regarding a pattern change around Christmas stemming from some weakening of what is expected to be a strong Pacific jet stream. The basis for this is the expectation that the Madden Julian Oscillation appears fluid as opposed to stagnant and poised to move into Phase 7, which is a more neutral phase for winter weather in eastern North America as opposed to the current phase 6 which is considered mild. The fluid nature of the MJO is certainly encouraging but it's going to take some time to break down the current combination of unfavorable teleconnection indices. Aside from the strong/tight jet stream in the Pacifc, we still have a very unblocked pattern at high latitudes highlighted by an Arctic Oscillation projected to range between a +1 and +2 for the next 2 weeks. A negative AO is absolutely vital for winter weather south of 40N and fairly important (though not vital) for winter weather in Vermont, especially in December. That said, I would like to seem some stronger evidence that the prevailing "unblocked" jet stream regime will break down.

 

Friday, December 3, 2021

Wintry temps and a little snow this weekend and some snow potential continues for the middle of next week before the weather pattern takes a turn for the worse

 The forecast for Monday has deteriorated to trash which is a rude interruption to what could have been a nice early December 7-day stretch of sub-freezing temperatures. All indications are that this will be a tough month for winter-weather lovers in New England. We've talked about all the feedbacks working against us and when you add in a prevailing + Arctic Oscillation (AO) index and a positive Eastern Pacific Oscillation (EPO) the results will be predictably bad. We continue to see some very cold air positioned over Alaska and much of northern and central Canada but its a challenge to put this chill to good use in December, and Monday's torch is a perfect end-result example. 

We still have a wintry weekend to look forward to. Sunshine and near 10-degree temperatures early on Saturday will give way to some clouds. The snow from our benign weekend disturbance is not expected to arrive until after the ski day and in the evening. Northern Vermont appears to be the best area of accumulating snow in this period and this appears to be a fluffy 1-3 inch situation for MRG. Models are indicating a few clouds for Sunday so perhaps not total bluebird, but we can expect a decent dose of sun during the day and the warm advection clouds are not expected until after it gets dark. 

Most of the east coast is now expected to get a torch on Monday with soaring temperatures. Cold will linger for a few hours in Vermont under clouds but the inversion is expected to mix out during the afternoon allowing temperatures to soar into the 40's. A short period of rain is likely at some time late in the day before a cold front dries it out and cools it down. Sub-freezing temperatures are then expected to prevail for most of the rest of the week (through Friday) but can we get some snow before the weather pattern fundamentals turn ugly around December 10th. 

We have a couple of models indicating most of the moisture associated with a weather system in the middle of next week will be south of Vermont. We also have the American GFS model showing a more direct hit and decent dose of snow. Mix that data all together and you get an appetizing model consensus but I have some concerns about whether this system can actually organize itself enough to send moisture deep into interior New England. We have a very healthy baroclinic environment along the eastern seaboard working for us so the situation is certainly worth monitoring. 

The period between December 10th and the Winter Solstice does not look good as I mentioned. A Friday afternoon run of the European Operational model did bring in a decent area of cold late next weekend into Monday December 13th following a wintry mix-type event on the weekend of December 11th-12th. This was not supported by the corresponding run of the Euro Ensemble so though I am inclined to generally disregard it, the model did illustrate how cold air in nearby Canada might successfully make an intrusion in spite of the lousy weather pattern fundamentals. The risk of a multi-day thaw and rain however is pretty high in this time frame and this would be the point I would want to underscore before leaving you all for the weekend. Enjoy the wintry temps while we have them !


Wednesday, December 1, 2021

Cold weather and some light snow for Saturday while best snow potential shifts to the middle of next week

Our friends up in King Salmon, AK, one of my favorite names for a town, just finished the month of November with temperatures averaging 21 degrees below normal. King Salmon is not especially inland, sitting not far from the Kvichak Bay adjacent to the Bering Sea and just east of the Katmai National Park. In other words, this is pretty far south in Alaska and highlights what has been a month of incredible cold along the southern coastline of our nation's largest state. Much of this cold remains as of this post and has expanded to include much of northern Canada. It will remain locked in place for the foreseeable future and will make occasional appearances in Vermont but a bit more infrequent than I would like, especially after December 9th. 

Up until this aforementioned date, we do have some winter to discuss. The dynamic looking BC bomber system is unfortunately a flop. With the track of this storm now expected to be well over Quebec, the storm and its relative strength will help push above-freezing temperatures into most of the low lying areas of Vermont Thursday and any precipitation will be of the mixed or rainy variety. Above 2000 feet, rain showers Thursday afternoon will likely turn to snow by the evening. Flurries and snow showers are likely to continue into early Friday as colder air settles into the state. The mountains can expect a small accumulation from all this but I had hoped for more and I wouldn't bet on more at this point. I am more encouraged by another weaker disturbance expected to bring limited moisture to Vermont early Saturday. This arrives during a period of much colder temperatures and has the potential to provide our local high country with a few fluffy inches. Still a little difficult to say which part of Vermont will score the most from this moisture-starved system but we have as good of a shot at as anyone else of scoring a few inches. As I mentioned this disturbance comes during a decent multi-day stretch of sub-freezing cold which will begin with temperatures in the 20's Friday and continue through the weekend with single digit temperatures possible Sunday morning. Sunday looks like a December bluebird special, always appreciated by me during our darkest month of the year. 

I wish I had more conclusive and better info to report for early next week. The American GFS model has in the past and continues to show an inland Great Lakes runner, so much so in the last few runs that Vermont would get a full blown torch Monday and we would just forget about snow. Other data still points to a colder more wintry scenario but even this would be well short of ideal. Consensus has certainly moved away from the possibility of a storm tracking south of us and this makes the notion of heftier accumulations a very tough ask. My guess right now would be for a snow to wintry-mix conglomeration and we could get front-end thumped with a few inches. I am trying to avoid getting sucked into to any wishcasting vortex here and remind anyone that these lousy feedbacks (warm aggregate bodies of water around us) are not going to do us any favors during these close call situations. Some good news ? We do have a second chance during the middle of the week with models starting to signal at a more organized storm coming on the heels of a short-lived but somewhat intense shot of arctic chill Tuesday and Tuesday night. 

The longer range continues to look the same and not especially encouraging. Were it January or February, I could muster up some optimism that clashing of very cold air in Canada and mild air in the southeast US would serve us well. Combine the aforementioned adverse feedbacks with a decidedly +AO/EPO and tough sledding is clearly the most likely result. Any sustained stretch of milder air does appear delayed until at least the very end of next week (December 10) which would be a positive. The other positive continues to be the relative proximity of the very cold air in Canada. Much of the eastern United States is likely to avoid it but we are Vermont and are special in this regard so might get a little. To summarize though, I do not expect the period between December 10th and December 21st to be especially wintry or snowy and we should at least one very significant thaw. It will however be cold in the Pacific Northwest and snowy parts of the Rocky Mountain west. I would expect a few snowy headlines in some unusual locations as well.

Monday, November 29, 2021

Mostly cold for at least another week in northern Vermont with several chances for small accumlations of snow and 1 chance for a bigger one

At the Knapp Airport in Berlin, the low temperature of 11 and high of 29 on Sunday officially measured at 9.5 below normal, falling just short of 10 below normal. So the 6-month streak of avoiding the "10 below normal or more" cold remains for now. It is very likely to fall this weekend with more intense cold expected to land on northern Vermont atop of some snow cover. This highlights what is a decent short term outlook extending out maybe 7-10 days which includes a few chances for small accumulations of snow and 1 chance for a decent storm. We have some concerning weather pattern fundamentals to contend with beginning around December 8th but even this potentially less than optimal pattern leaves some room for encouragement. 

A mostly cloudy and chilly day Tuesday should be followed by some very light snow Tuesday Night into Wednesday. This is a very benign weather disturbance but is still capable of yielding a very low density accumulation. Milder 30-plus degree temperatures and some sunshine then follows for Wednesday before clouds in advance of a vigorous BC bomber type system arrive Wednesday evening. Even without a ton of moisture, this southeastward moving system has an impressive look. Current forecast models have our area of north central Vermont missing the best quadrant for snow but not by much (we would be 50 miles too far south). Even still, we should expect a period of snow Thursday along with near freezing temperatures and some snow showers early Friday with the arrival of colder weather. A small 1-3 inch accumulation would be my best guess with this for now but this could rise or fall depending on the exact track of this weather system. 

The Thursday storm is the first of what is a relatively active pattern with one consolidated jet stream and a decent supply of early December chill in Canada. An initial surge of colder weather should arrive by Friday which is likely to mark the first of a 5-day stretch of sub-freezing temperatures. We are likely to miss out on some light snow that might impact portions of the Mid-Atlantic Friday night but temps could fall to the single numbers and only rebound into the teens on Saturday with a repeat of this for Sunday. The potential storm would impact the region Sunday night or Monday. It appears to be involve energy from the Pacific that would get a big infusion of energy and moisture from the relative warmth of the Atlantic Ocean. Models aren't even close to sorting through particulars of this storm or even the presence or absence of said storm. I've seen a wide variety of outcomes which would indicate a forecast that is likely to evolve over the coming days. If there is an identifiable trend in recent data, it does involve colder temperatures during the period in question which is certainly good news. This cold weather is likely to remain in place across New England through at least Tuesday December 7th as I mentioned but I could certainly envision this continuing through most of next week in spite of some operational models suggesting a mid-week torch. 

The longer range ensembles are painting a picture consisting of a pattern without any high latitude blocking and with more averse jet stream activity in the Pacific. A strong mid-latitude ridge is expected to develop in the Pacific and unsurprisingly, it is indicated to set up right over the warmest blob of water discussed in the seasonal outlook. As a result, Arctic air is expected to retreat after December 8th so where is the good news here ?. Well, we successfully managed to get some of the coldest air in the world on our continent and it should remain there even as the pattern  turns move adverse next week. As I mentioned in the seasonal outlook, we are facing down some pretty tough feedback mechanisms in the form of various bodies of warm water temperatures (Great Lakes, Hudson Bay, western North Atlantic Ocean) .We need some help in this regard and we are getting it in the Hudson Bay, a region of central Canada that saw some incredible warmth in Autumn. Much of northern Canada and especially Alaska has turned very cold however and those conditions are expected to remain over the next two weeks and beyond. We can thus be confident that the Hudson Bay will freeze on schedule (mid December), eliminating at least one bad feedback ahead of Christmas. Additionally, the colder weather in Canada will be close enough to New England for an impact and ensembles, although milder after December 10th, are not suggesting a sustained torch in Vermont.


Wednesday, November 24, 2021

2021-2022 Winter Outlook: La Nina returns in a more weakened state but a lot of arrows still point mild !

 It's been a long wait for colder weather this autumn across northern Vermont but winter is coming in fast now that the calendar has turned to November and our friends at Sugarbush are celebrating opening day as of this posting on November 24th. As I get older, I feel like the shorter days almost requires one to get excited about the arrival of ski season and the various winter weather possibilities. Yes, the caution flag was raised early this autumn with La Nina lurking and a seemingly endless stretch of anomalous warmth stretching into October but the weather is always evolving and I like to hold back any bold predictions until late November allowing weather conditions to continue to evolve.

The last time cold weather set off any fireworks across the lower 48 was February. Since then, the weather has oscillated between slightly above and the much above range not only across interior New England but for much of the United States and Canada. Locally speaking, what has made this several-month stretch of warm weather unique is the glaring lack of anomalous cold, even for a few days. You have to go all the way back to Memorial Day weekend to find a day in northern Vermont that was at least 10 below (the already recently warmed) 30-year average. To add some perspective to this, we have recorded 28 days since Memorial Day with temperatures at least 10 above average and we've yet to break the streak even with the recent colder weather we've seen the past few weeks. It explains the late foliage year we experienced both in the Great Lakes Region and New England since multi day stretches of anomalous cold are very much a normal part of New England should see from the standpoint of variability. The extended period of warmth has created some problematic feedbacks that we can discuss in a later paragraph but this has certainly been the biggest headline when discussing the weather this past several months. With that, we are ready to take a plunge in to the "what can we expect this winter" domain.

ENSO (El Nino/La Nina) 

Let us start with the ENSO situation and get a handle on that. Last year we had a significant La Nina that appeared to be building as we progressed through November of 2020. That particular ENSO peaked in very early December and very slowly subsided as we progressed through the duration of winter, finishing March at less than half the strength of that early December peak. Once again, we are seeing La Nina conditions in the equatorial Pacific but they are weaker than last November by about half a degree. Though this still puts ENSO into what I would consider a more "La Nina" mode, if equatorial waters were to warm, relative to average, by about half of a degree C, we would be be looking at a nearly neutral ENSO. Though I tend to prefer a weaker El Nino as opposed to La Nina, a weakened ENSO of any kind does serve our winter weather needs a little better. This relationship is hardly perfect but based on about 60-70 years of hard data, a strong ENSO of any kind does load the dice for a dud winter. We've had 15 strong ENSO winter's in the last 60 years which comes out to about 1 in 4 and 8 dud winters in that same time frame which comes out to a little less than 1 in 8. About half of those dud winters occurred with a significant ENSO present though which suggests that a strong ENSO about doubles the chances for a 2015-2016-like abomination. This winter marks the 10 year anniversary of the 2011-2012 horror show, a torch-fest largely brought on by some horrific prevailing jet stream conditions in the Pacific. We had a modest La Nina that winter that measured out at about -0.85, not too dissimilar to conditions right now. Interestingly, the 2011-2012 winter came on the heals of a stronger La Nina and one of the snowier winters in New England illustrating the imperfections in this relationship.  The best way I can summarize the ENSO situation for this winter is that I am not too worried about it right now and some other combination of factors will allow our weather to sink or swim. Here is a chart I put together showing a recent history of ENSO during the winter months and a few adjectives describing Vermont weather during that winter. 

 

All Things Pacific 

Moving on to the all-important Pacific, and I can underscore all important because it's had much to say about the outcome of recent winters. We've seen about 20 months of negative PDO conditions with the index generally amplifying in that direction over that time frame. They've done a number on some of my data sources regarding the Pacific Decadal Oscillation but the index, according to this graph, appears to be hovering around -2 which is pretty significant. We haven't seen anything like this since late 1999 into 2000. Though I consider the state of the PDO very significant, I prefer taking the deeper dive into sea surface temperatures in the mid-latitude Pacific in search for better answers. Why do I prefer this ? Because the actual PDO index seems driven heavily by the state of SST's over a small region near the west coast of North America while the weather pattern can be driven largely by the state of SST's over a broader expanse of the Pacific. 

I affectionately refer to the "red blob" as a persistent but vast area of warm SST's in the mid-latitude Pacific. It's been there for a while now, over two years to be exact. It largely ruined the winter of 2019-2020 and was an adverse force last year but was largely neutralized by prevailing (-) Arctic Oscillation conditions. It's still there as of this November but over the past 6 weeks, the area of warmth has shrunk and has shifted south and west. Meanwhile, an area of cooler water has strengthened and now covers a large area of the northeast and east-central Pacific Ocean. I suspect much of this has been weather pattern driven (but I can't say that definitively) but it's been interesting to watch this happen while at the same time, the +EPO has been mitigated and conditions in the Pacific look marginally favorable for cold weather in eastern North America over the next few weeks. Overall, in spite of how negative the actual PDO index is, I consider the conditions in the Pacific to be better overall than they've been the last two years. This doesn't clear all the roadblocks however since we will certainly need help from other fundamentals. 

 


 

 SST Anomalies last November


 


 

 SST Anomalies more currently

 

 

Snow/Ice Buildup

The buildup of snow/ice across both the North American continent and especially the Northern Hemisphere as a whole, in autumn, is certainly something I and many others consistently watch when trying to make a guess on weather for an upcoming winter. Over the last several years, we've seen rapid buildup's of snow across the NH and the trend has been so pronounced and so consistent that it is reasonable to speculate that climate change might be playing a role. More specifically relating how changing thermals in a less icy arctic in autumn might directly cause a more rapid buildup of snow over these areas. A reasonable assertion to make but this is where I punt to the more academic crowd for more definitive answers. In the case of this autumn, 2021, snow coverage in October registered well under 20 millions of sq km for the first time in 10 years. The exact number 18.14, is more in line with the 55-year average but additional data in November is showing that we are now below average we are now on pace to have the slowest buildup of snow since 2008-2009. While the above is certainly noteworthy, so are sea ice conditions in the Arctic throughout the summer and into fall. They made a bit of a comeback this year with substantially less ice melt than in 2019 or 2020 and a fairly rapid freeze-up in October/November. Recall that the Chukchi Sea, the area of water northwest of Alaska, was wide open well into December during the fall of 2019 and has completely frozen as of the middle of November 2021. This contrast in conditions would lend credence to an open water/rapid snow cover relationship and certainly an interesting potential consequence of our warming world. 


 

 

 Snowcover the last several October's

 

 

 

 


 

 


 

 

 

 

 

 

 

 

For this winter, the sizable drop in snow cover over the Northern Hemisphere, by 3 million sq km and almost 7 millions sq km in November can't be ignored. In spite of better sea ice conditions the slower buildup of snow is still a warmer feedback this winter that we will have to overcome. Though we've covered this ground before, its always worth a reiteration. On a scale as large as a "hemisphere" a larger snow cover area provides a more fertile ground for cold air pooling and more intense areas of arctic chill. 

Atmospheric Tells

Our last section covers the "Atmospheric Tells", a broad category that analyzes whether recent trends in weather both locally and across the continent reveal any behavioral tendencies that might either continue or might portend future weather conditions in any way. I always try to be very cautious in sifting through this data, trying to focus on consequential variables while ignoring those that might be immaterial. This is a very subjective exercise and leans heavily on the years of experience doing this and can rely heavily on persistence-based forecasting. Though a "persistence" forecast, essentially calling for the continuation of weather conditions currently being experienced, isn't exactly as bold as bombing it down Paradise, it deserves a place in the equation. In the case of this year, it's an unfortunate place since the most glaring trend in recent weather has to do with the persistent warmth and particularly the lack of intense anomalous cold discussed in one of the opening paragraphs. This long duration of this recent trend has been self reinforcing because of the negative feedback loop that the region has been sucked into. The warmth has been expansive, especially this fall and covers all the Great Lakes, Northeast and much of eastern Canada. The result has been a Great Lakes aggregate, parts  of the western Atlantic Ocean and much of the Hudson Bay that are seeing water temperatures of 5 to as much as 10 degrees F above average. Some of these anomalies have been mitigated in the last few weeks by a changed weather pattern but more work will need to be done. Much of Canada is expected to be quite chilly over the next few weeks going into early December and I am hopeful that we can start to freeze the Hudson Bay close to the usual time. Right now, that very large, nearly 500,000 square mile body of water is wide open making it difficult for intense cold to make the trip into eastern Canada without modifying substantially. 

Outlook/Summary

In a final summary, we can start with the  more encouraging news relating to the changes discussed in the eastern mid-latitiude Pacific Ocean and an altered weather pattern finally mitigating some of the negative SST feedbacks in the Hudson Bay, Great Lakes and western Atlantic Ocean. La Nina remains a force albeit a little weaker than a year ago. Mostly however, the data is suggesting a mild winter. Even with the recent changes in the Pacific, ocean water temperature configurations there remain adverse and we were only able to overcome that last year with an usually negative and persistent negative Arctic Oscillation. Those conditions are very unlikely to repeat. The worst roadblock on the temperature side has to do with much of what was discussed in the previous paragraph. Recent trends have been horrible for cold and we now have an ugly set of feedbacks to overcome. 

It's more easy to retain some optimism on the snowfall side of things. La Nina winters, even the weaker versions, favor a storm track aimed more at us than south of us and though I would expect to see a wide variety of precipitation types, interior New England would be a favored location to "bullseye" a big storm.  Warm water in the western Atlantic is not especially positive for the temperature outlook but it can provide a lot of fuel for big storms and I am optimistic we see a few. Barring something anomalous from the teleconnection indices we monitor, we should expect both good and bad periods of weather overall with decent stretches of weather rudely interrupted by an inopportune thaw. Nothing unusual for Vermont. Welcome back everybody and Happy Thanksgiving ! 





Friday, April 30, 2021

Winter 2020-2021 review - What could have been !

 The 2020-2021 ski season was certainly compromised as a result of the ongoing Covid19 pandemic but we still had one at Mad River Glen and we thank the efforts of all staff members that helped make that possible. On the weather side of things it was interesting because it almost always is.. We had two big east coast storms, a historic and very damaging cold wave in Texas and a persistently negative Arctic Oscillation yet in the case of northern Vermont, I can best summarize using 4 words. What could have been ! 


As expected, the winter was dominated by a moderate La Nina. It strengthened very quickly in autumn but SST's in key regions of the equatorial Pacific leveled off at about 1C above average and then began to fade late in the winter. Also as expected, the sea surface temperature configuration in the Pacific did create a weather pattern that was dominated by a strong Pacific jet stream which proved to be a mostly invariable force throughout the winter. The more dramatic and less expected distinction relates to the aforementioned Arctic Oscillation. Recall that the winter 2019-2020 was dominated by a very positive AO, one of the strongest recorded in the last 75 years, averaging an index over+2 over a 4 month period beginning in December and ending in March. Over the same period 2020-21, we saw an average AO of -.82 and the very positive AO we saw just recently in March blunted what would have been an even stronger negative number. More than anything else, it was the negative AO which helped daytime temperatures in the MRV average 2 degrees colder during the recent ski season than the season prior. This is not an insignificant figure over a 4 month period and really should have resulted in more snow across the Vermont high country. The stake at Mt Mansfield doesn't lie however. The snow season started below average and never caught up and quite honestly, I chalk it up to whole lot of bad luck. It simply should have been better given the selection of ingredients available to us. I'll expand on this point more when we review what happened in February. 

November of 2020 bore no resemblance whatsoever to what we saw during Snowvember 2018 or even last year. We started mild, we finished mild and the minimal snow we saw in between melted by the start of December. There was almost no support for early season winter weather in November across New England but the AO made the critical turn early in December and this began a long period of time where high latitude blocking effectively suppressed surges of more intense milder temperatures (with one exception). Interestingly, the blocking was largely confined to an area that included Greenland, the Davis Strait, the Labrador Sea and portions of the Hudson Bay. Having such a large block in relative close global proximity to New England actually prevented eastern significant amounts of Arctic cold from impacting eastern North America; nonetheless, it was enough to finally bring a stretch of sub-freezing temperatures to the northern Vermont high country beginning around December 5. The coldest stretch of days occurred in the middle of the month out in advance of what was the first of two major winter storms for New York and New England. Initially forecasts kept the storm south of Vermont but hopes were kept alive by the "northward shift" possibility, which specifically refers to a medium range model bias that overly limits the impact of nor'easters on interior New England. The bias is real and it happened again, as forecasts began shifting the track of the storm northward and higher resolution models began pinpointing the presence of a massive pivoting band of snow within the storm near the Vermont/ Mass border. Man, did we get close ! The MRV missed what could have been some historic snow by maybe 50 or so miles. In Vermont, the band concentrated in a line from near Granville east to Windsor, Vermont and produced as much as 50 inches of snow with high amounts recorded even in areas that often get screwed because of unfavorable oragraphy. It was frustrating to miss on some terrific early season powder by very little but it foreshadowed much of what became some very bad luck in northern Vermont that plagued us throughout the season. The storm did showcase the material improvements in higher resolution modeling, specifically how forecast data was able to indicate the presence of the pivoting heavy snow band. Ski areas such as Magic Mountain and Okemo certainly got a chance to bask in the glory of this storm for several days. Further north, we managed to build a 6-10 inch that seemed to accompany a growing sense of doom as the forecast for Xmas deteriorated. 

Christmas was indeed a disaster but guess who had it on the bingo card back in October when Vermont Ski and Ride came calling for an outlook ! I got extremely scientific with this prognostication going with the theory that 2020 was full of piss and vinegar so why should Christmas be any different. The storm was absolutely a freakish occurrence given the weather pattern by getting caught in the jet stream blocking in eastern Canada rather than tunnelling underneath as most storms do in those circumstances. It was windy, it was mild and our snow was all but gone by December 26th. It was a terrible but fitting way to end a not so great kind of year. 




The start of 2021 brought almost instantaneous improvement to Mad River Glen. High latitude blocking in the jet stream finally began to score some victories with the first coming from a very garden variety storm that moved from the lower Mississippi Valley to southern New England late on New Years Day. Steady snow fell across much of Vermont and much of ski country in the northern part of the state scored 6-12 inches. Much of what fell ended up staying on the ground through early March thanks largely to the persistently negative Arctic Oscillation. Interestingly, however, eastern North American remained largely devoid of intense arctic chill as the plethora of high latitude blocking structures, were, for a time, closing pathways for polar air to move from the Eurasian Continent. That would eventually change but for much of January, Vermont manage to experience a very impressive streak of sub-freezing temperatures that were, at the same time, above normal. Following the early month snow, a stretch of dry weather persisted for over a week and temperatures remained rather comfortable, staying mostly in the 20's and low 30's and never really falling below zero. We began to see signs of a storm for the MLK holiday but with the cold weather holding a very tenuous grip on New England and the Christmas fiasco still fresh in my mind, I will admit some apprehension. It ultimately looked apparent that the storm would not follow the same fate as the one on Christmas Day. The initial storm occluded over in Iowa and the main precipitation producing storm reformed over New York City early Saturday. Though the snow consistency wasn't optimal everywhere, the storm was the best event of the season with over a foot falling across the high country surrounding the MRV. Colder weather in the ensuing week along with several small accumulating snow events made for some terrific conditions and that persisted through the rest of the month even though the MLK storm was the last to impact the state for the remainder of the month. As for the arctic cold, it finally showed up in New England on the last few days of January with temperatures dropping to as low as -20 in spots on Saturday January 31st. 


February 2021 is a month that will be long-remembered and not necessarily for the right reasons in some parts of the country. For the ski areas in northern Vermont, I consider the outcome quite unfortunate since the chess board appeared set up for an absolutely glorious stretch of winter and the results were rather ordinary at best with our rain-less, thaw-less streak ending late in the month. The 2nd of the the season's 2 big nor'easters struck on February 1st and 2nd as a classic Miller B type event with a Midwest storm transitioning its energy and moisture to what would become a much stronger coastal system. Indeed it was very strong storm and proved to be an epic event for the NYC metro with upwards of 2 feet falling in some suburbs. Snow did reach most of northern Vermont but accumulations were very garden variety and fell short of even some modest expectations. The snow that did fall was nonetheless a welcome addition to a 5-week stretch of sub-freezing, rain/ice-free weather and the week that followed was a productive one with small accumulations of snow making the first full weekend of the month, one of the best of the season. It was a point in the season where everything looked as if it was going to come up roses as the Pacific jet appeared to be finally relaxing allowing the persistent blocking at high latitudes to win the day and the month. What was even more encouraging was the continued presence of a La Nina-style southeast ridge; which, appeared ready to steer multiple storms in our direction as oppose to a confining the impact to coastal areas. Normally, I would embrace this setup and do so enthusiastically fully expecting epic results. 

The weakening Pacific jet was as an absolutely critical occurrence and indeed allowed the blocking at high latitudes to produce an highly amplified pattern capable of producing a cold wave of historic proportions across the Texas, Oklahoma other parts of the middle of the country. Arctic air began its southward advance around February 7th, initially affecting northern latitudes including Vermont. By the weekend of Valentines Day however, the pattern would become even more amplified allowing very extreme cold to make a full on assault on portions of the Gulf Coast. As the cold continued to look more intense in Texas, it was gradually appearing less intense across New England and expectations began to shift from bone-chilling cold to a more defensive posture of fending off surges of milder air. The third week of February, you know the one that includes the holiday looked like a could be a 2-storm type of week and ended up being a wide-left and a wide right form if ugliness. The first storm late Monday into Tuesday involved a big push of mild air and had lots of moisture but an initial, decent burst of snow turned to sleet and ice. The 2nd on Thursday, Feb 18th, made a southward shift in the days leading up to the event and resulted in little to no snow in northern Vermont. The month ended with a muted thaw but and it was a microcosm of a month that should've been better. 

And while Vermont was glazing over with ice or getting bested by coastal cities on snow, Texas was freezing in darkness. The cold wave sent temperatures to -14 in Oklahoma City which is about as cold as the MRV got all winter. Readings were below zero as far south as Dallas/Ft Worth and a low as 10 degrees in some outlying suburbs of the Houston Metro. The intensity and duration of the cold wave stretched an already flawed electricity market in Texas, overseen by ERCOT (Electric Reliability Council of Texas) beyond its breaking point. Much has been written and politicized about a weather event that proved more impactful than multiple high category  hurricanes making landfall at once.  Though I don't operate within the ERCOT sphere, the power markets remain part of my home turf and it was disappointing to see misconceptions made by familiar characters in the aftermath of the event. The most common one involved laying the blame at the feet of renewable sources of energy such as wind which supply Texas with a critical amount of electricity throughout the year. Texas, in fact, leads the nation in wind generation, a source of electricity that many cold weather climates rely on in high demand periods and do so successfully. The Texas market however does not operate with the necessary incentives to seamlessly operate during high load events and especially during historic cold waves. When the postmortem assessments are completed, they will almost assuredly show how dangerously vulnerable the grid was to a historic cold wave and that planning for such an event was very poor with a limited sample size of data used to make an adequate risk assessment. Texas, more than any other region, is susceptible to gas freeze offs which effectively shuts off vital supplies of  natural gas to power plants when they need it most. Wind, could have provided Texas with a critical backstop but ERCOT failed to provide generators with the proper incentives to winterize their wind generation which is commonly done for wind generators farther north. ERCOT also operates with a reserve margin that is considerably lower, often less than 10 percent during high demand periods, than our market (NEPOOL) in New England which is typically closer to 30 percent. A  less than 10 percent reserve margin in a region of the country that can experience very volatile weather and energy demand is not a market structure that ensures reliability and is instead hoping for a combination of luck (which always runs out) and market forces (which have a funny habit of conspiring against John Q Consumer at the worst time) to operate successfully.  Don't let anyone tell you differently, the situation in Texas in February was a miserable embarrassment for free-market advocates who can wax poetic about how all of this serves the consumer. It serves no one to freeze in the dark, which millions did for a span of several days.

The milder turn the weather pattern took in late February continued into March. The AO which helped power the widespread cold outbreak in February abruptly turned positive in late February and stayed positive through March and when combined with a still active Pacific Ocean jet stream helped make for a rather torchy and surprisingly dry month. That said, winter tried to make a last stand in New England and Vermont was one of a select few states to see a sustained stretch of winter early in the month including a day, on March 2nd where temperatures struggled into the teens. Fittingly however, Vermont saw a very limited amount of snow when it was cold. The high country did see a few decent snow squall events but at no time do we see snow from an organized weather system. Ski country did see some excellent weather for spring skiing however. By my count, the MRV got to experience 7 days of near 60-degree, sunshiney weather which is unusual for us and gave skiers several days of healthy spring conditions. Too much of a good thing can present a problem for MRG lift service however and all of that warmth ended the official season on April 3rd. 

April followed with more surprisingly pleasant spring weather in Vermont but this was rudely interrupted on April 15 by an elevation snow event which brought some heavy snow to the same portions of central and southern Vermont that seemed to get much of the best snow all winter. Another even colder event on April 21/22 brought snow to the northern Vermont high country and helped make April a snowier month than March in spite of a lot of warm weather. 

Years ago, a very experienced and seasoned forecaster shared with me his feelings about what was going to happen during the upcoming summer of 1999. He was a believer that the 11-year sunspot cycle could be correlated with the North American weather pattern. The 11 year sunspot cycle refers to the oscillating measure of observed solar activity where it takes 11 years to complete one full cycle. There are peaks and troughs of such activity with the most recent peak occurring around 2014 and a trough having occurred very recently. He never did actually sell me as to why and how the correlation exists but he pointed out how hot and dry summers have occurred in the same point of each cycle stretching back (at the time ) of 50 years. 1955, 1966, 1977, 1988 were all hot and dry with a high activity of tropical cyclones. The forecaster nailed the 1999 summer forecast and though I never was completely sold on the sunspot link, the verification stuck with me and I remembered it going into the summer of 2010. Once again it was hot and dry. So, if you made it this far in the review and in the paragraph, you can probably see where I am going with this. 


I won't sell folks on the idea that the sunspot cycle is a predictor of a prevailing weather pattern. I really don't know. I do believe however, as many of you know, that the weather pattern can provide tells as to future weather. I've watched many dry weather patterns in spring lead to hot and dry summers. We've had some precipitation in April and some more is on the way in the upcoming week but we've been running deficits for several months with the biggest occurring in March. Unless we get a wet May that cuts into the building precipitation deficits however, count me as someone that believes a very hot and dry summer is on the way. Yeah, this kind of thing is a little too anecdotal and might need a scientific infusion but I have a sentimental weakness for some of that stuff and it was a good way to end another season of blogging. 

Hope everyone made the best of the season under some trying circumstances. Hope everyone enjoys their summer and we will talk again late next fall !!