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.

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.

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 !

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. 

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.

 

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 !

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.