Think Snow, Tweet Snow !!!

Friday, December 28, 2012

Looks at least 6 for Saturday night into Sunday and cold through January 5

And suddenly, its been a great start to the 2012-2013 ski season. Nothing like 20 inches to erase a few bad memories. As mentioned via twitter and I am sure in every other available forecast, more snow is on the way. This system is also organizing in the lower Mississippi Valley and will ultimately be centered near the Virginia tidewater before venturing off into the Atlantic, just south of the tip of Cape Cod. Such a trajectory typically either gives central and northern Vermont a glancing blow and sometimes nothing at all. With this system, there will be a decaying low pressure center north of the coastal low that should allow the frontogenetics (I literally just made that up), to be relatively favorable for a healthy period of snow. It should all start around the time of last tracks Saturday and should continue through the evening. My morning on Sunday, most of the heaviest snow will be over, but occasional terrain induced snow showers will continue throughout the day. If all things go according to plan, we could get an additional 6-plus inches with 4-6 of those inches before first tracks time Saturday.

After Sunday we have roughly a week to enjoy the fruits of our hard earned labor. During this period, we expect a polar vortex to take a run at New England. Not every day will be bitterly cold but some very cold air will make a charge at the region for at least a short period, probably very late next week. It will also be pretty chilly Sunday with temperatures in the teens while a biting wind thanks to our departing storm sends wind chill readings below zero. Monday afternoon temperatures will be a little more comfortable as winds subside. With the polar vortex approaching, it is unlikely that any major snow producers will venture this far north. Instead, weaker disturbances rotating through this PV will bring chances for lighter snows. The first such disturbance will arrive Monday night and may be good for an inch or two by Tuesday.  The next will arrive either later Wednesday or Thursday and will mark the edge of the coldest weather the region has seen since February of 2011. Again any snow will be on the lighter side but temperatures will plummet later Thursday with readings perhaps getting well below zero by Friday and struggling to get above zero during the day. The chill should continue into part of next weekend before abating somewhat Sunday or Monday. I seem to remember that squeaky snow on my ski's when it gets really cold in Vermont but it's been so long since we have experienced some real chill I have almost forgotten that sound !

For those later arrivals to the blog, we have discussed how a ridge in the east-central Pacific ripped apart the first half of December in spite of some otherwise favorable high latitude blocking conditions. I have nicknamed this feature the "evil empire" since it successfully destroyed the winter of 2011-2012 and continues to be pervasive to a lesser degree this winter. I am very sorry to report that this feature will once again rear its very ugly head by next weekend and this spells trouble for the middle of January. We might be able to get through about January 7th or 8th before we start facing the consequences, but face them we must at least for a short time. The feature will temporarily force the trough into the western U.S. and will produce another succession of painfully strong Pacific systems. This will force the arctic cold into a temporary retreat and allow for a period of mild weather between the 8th and 15th of January. Ensembles are split on how all this evolves and I was encouraged that the European forced the Pacific ridge back toward Hawaii quickly and perhaps this would limit any damage.

Lets enjoy this stretch while we can though !

Thursday, December 27, 2012

Amazingly, no adjustments needed to our 15-25

Pretty remarkable actually considering the frequency at which mother nature likes to throw its knuckle balls. Mind you, a knuckler could still be thrown. The National Weather Service issued blizzard warnings for northeast Indiana and northwest Ohio Wednesday and a vicious dry slot cut down snow accumulations quite drastically as if to mock the forecast. Us powder hounds have suffered enough in the past year and we are in no need of any mocking. Sure, we too could get a "lull" in the storm during the day Thursday and snow accumulations might be a little lower as a result. The last cycle of model guidance remained consistent however and still indicates well over a foot of new snow on the mountain by the end of the ski day. If your headed up to the mountain Thursday and Friday, make a few turns for me.

We need to do a more complete update Thursday detailing the Saturday storm which is expected to give us a glancing blow but perhaps a light accumulation.

Monday, December 24, 2012

Bring It !!! 15-25 inches Thursday and Thursday night !!

Models continue undulate somewhat on the track of Thursday's nor'easter. For the record, I will absolutely not conform to The Weather Channel's efforts to name winter storms as the National Hurricane Center does with hurricane's. This is a silly crusade and one that I hope will die an early death. Last night we saw a cycle of model runs that actually did take the storm over New Hampshire and thus brought a layer of above freezing temperatures into Vermont. The recent two model cycles however and the information I am most comfortable with right now, has the storm strengthening over the lower Mississippi Valley Christmas Day, move into the Ohio Valley Christmas Night and then transition toward the Atlantic Coast, ultimately tracking between Boston and Cape Cod by Thursday December 27th. This is the ideal track for most of the Green Mountains, and although this storm is not predicted to be the intensity of Valentine's Day of '07, this strengthening to about 992 mb while the '07 storm was sub-980 mb, it will nonetheless be a big hit for MRG and much of the surrounding area.

The details are subject to some minor adjustments but the information we have suggests that snow will start just after midnight Thursday and begin accumulating in earnest by daybreak. At first tracks time on the 27th, we should have a few inches on the slopes while snow falls 1-2 inches per hour. Winds should be rather blustery at the summits Thursday, blowing from the northeast through much of the day. With any storm, there are variations in the intensity of the snowfall but the bulk of heaviest precipitation could certainly result in snowfall rates upwards of 3 inches or more. The concern with this event has always been a potential change to sleet or freezing rain. That risk for the mountain is now minimal but this critical line will not be far. The big east coast cities of New York and Boston will mostly be rain and cities like Rutland, Lebanon, Albany and Concord could see snow change to sleet and then rain. It looks to be another event where the place to be is north and in the mountains, somewhere such as MRG, which from what I hear, had a nice opening day Christmas Eve.

The snow could continue into part of Thursday night but should be over or taper to flurries by Friday with a total accumulation of 15-25 inches. This is not a forecast for valley locations so no emails from readers in Rutland that only got a slushy 6 inches. There won't be much time to worry about snow totals anyway since by then we will be watching a second weather system, and another potentially significant one. This second system, another southern branch product, will grab some moisture out of the gulf and track toward the Atlantic Coast Saturday. Right now it appears this storm will track further southeast, reaching the Virginia tidewater Saturday night. From here, the storm could either take a trajectory aimed more out to sea or turn northward toward the Cape. Either case would mean more snow for the northeast but the latter means another round of big snows for central and northern Vermont.

The pattern could yield one more big hit just after the new year as well leaving the mountain in fantastic shape in the early part of 2013. Around the time of January 5th is where I start to get nervous since there are threatening indications of a turn to more zonal flow. It's Christmas however and I am in no mood to discuss those things. Enjoy the holiday and stay safe !!


Friday, December 21, 2012

Potential December 27th storm looking better and better

The winter of 2012-2013 has gotten off to an inauspicious start to say the least and this is on the heels of one of the worst winters in the history of MRG. Can we finally get an extended period of winter now after another undeserved period of rain Friday ? Yes !!

The next 10-14 days will be as winter-like as anything the mountain has seen since February of 2011. Snow showers and a few snow squalls Saturday from the slowly departing occluded swirl should yield between 2-8 inches depending on the elevation. Anything that falls on the mountain, will do so on top of the few inches of the very dense concrete or conglomeration of half melted but now frozen snow. This is effective stuff actually when it is actually at the bottom and not on top. Sunday looks like a drier day than it did a few days ago which has been the exception in a weather pattern that has produced lots of precipitation of all varieties. And yes, there is plenty more to talk about and it all stems from an active southern branch and a pattern that will ultimately evolve into a more classic split-flow scenario (at least for a time). There are lots of goodies under the Christmas tree in such a regime. The first is a storm that is likely to bring its goodies further south on Christmas Eve/Christmas Day unless there is a late 100 mile shift to the north. It is a weaker weather disturbance and it precedes a much more potent weather system later in the week.

The storm that deserves all the attention and most of the discussion should strike the region in some fashion around the time of December 27th. It is a low pressure center that will efficiently suck moisture out of the Gulf of Mexico and proceed northeast, eventually evolving into a ferocious noreaster. There is a fresh supply of cold air with this storm and since its formation is farther south and east, it will not prematurely amplify before interacting with the Atlantic Coast. The one critical question that remains is the track. There has been a loose consensus amongst the models to allow this system to travel just inland and this would bring above freezing air well into southern New Hampshire and perhaps threaten parts of Vermont. The storm is still 5 days out so a shift 50-100 miles southeast or northwest could make all the difference. Either way, the result appears to be a net very positive and potentially a significant amount of snow, our biggest in a while.

There also could be more where that came from as there are some indications of a follow-up snowfall around the time of the 30th and below freezing temperatures through the early days of 2013. For now, the blog will stay focused on our potential December 27th event. Hopefully it is worthy of such focus.

Wednesday, December 19, 2012

After some rain Friday, snow for the weekend and maybe some more next week

The mountains hung in there Tuesday and in the end really didn't see too much rain. With the additional snows Tuesday night, Mad River Glen is dare I say, a winter wonderland just without the skiers. Attention now shifts to the big storm set to brings its bag of goodies by Friday morning. I have some good news to report with this system but just as they like to say "all politics is local", all news is also relative. I set the bar pretty low with last night's update so lets see if we can raise it a bit.

This very powerful storm system will get pretty wound up across the Midwest Thursday bringing heavy snow, gales, and even severe thunderstorms as far north as the Ohio Valley. The storms early and very deep amplification does not bode well for interior New England and as has been mentioned already, warm marine air from out over the Atlantic will flood the region Friday morning. If precipitation starts as snow late Thursday night, it will go over to rain Friday and we could even hear thunder once or twice. So where is the good news you ask ? We can't do much about the slice of warm Atlantic air but models do show this storm evolving very quickly and thus occluding very quickly. By late afternoon Friday or into the evening, colder temperatures will gradually become re-established over the mountain and we should see a quick change over to snow. In the end, the rain and above freezing temperatures will probably persist for roughly 6 hours. A swirling occluded system, such as this, will make the storm appear like a poor man's hurricane by Friday night on satellite imagery and the center of circulation will gradually make its way into the Gulf of Maine by Sunday. The slow movement and instability associated with this storm should allow for occasional snow between Friday night and Sunday morning. Snowfall could be significant before its over, perhaps upwards of a foot or more across the upper half of the mountain.

There is another storm system that should garner plenty of discussion. For one, it could be very significant. Secondly, the likely time-frame is right after Christmas, traditionally one of the most popular times to make a few or several turns. By Christmas Eve, polar air, of a weaker intensity will cover a broad area of both the Upper Midwest and New England. Meanwhile the next in this continuing series of storms will organize in the southern plains, gather moisture from the Gulf of Mexico and proceed northeast around Christmas day. This system will have more cold air to work with than the preceding few storms but questions and uncertainty remain. The main concern involves another potential premature amplification across the center of the country. Would this happen the result could include precipitation other than snow. Other questions regarding the organization, timing and track of this feature could also hold a lot of sway on the eventual forecast. I am cautiously optimistic, but its early so lets just see how things play out.

There are conflicting indications as we heard toward 2013. There are indications that the evil ridge in the west-central Pacific migrates back to the east and starts creating more mischief. Both major ensemble packages do suggest a trend back toward warmer temperatures just prior to the New Year. At the same time, a succession of recent European Ensemble runs have trended toward a negative AO just before the New Year and have also allowed some of that ridging to extend into the Yukon in northwest Canada. If we can keep the ridge axis in the Pacific west of Hawaii and finally get some ridging in western Canada, it would produce a very ideal split flow scenario full of storminess and Arctic chill. Lets end the discussion on that and hope for the best


Monday, December 17, 2012

Wet weather for Tuesday and again Thursday night

As expected, heavy precipitation is advancing northeast as below freezing temperatures gradually get scoured out of most of Vermont. Forecast atmospheric cross sections through the day Tuesday reveal that temperatures will simply be too warm to support snow in most locations and instead will see rain with some occasional sleet mixed in. The above freezing layer will hover close to the surface and should extend up between 3,000 and 5000 feet. This means that some of the high summits could still see some wet snow through the day tomorrow but even in these elevated locations, temperatures could challenge or exceed the freezing mark. Precipitation will become less intense and more sporadic Tuesday evening and night but also turn to snow as temperatures slowly move back toward the freezing mark.

I'll have a more complete update Tuesday evening but there is another intense storm late this week that is destined to impact the region. This system will amplify across the Midwest and over-amplify thus allowing a destructive swath of very warm temperatures to advance deep into New England Thursday night into early Friday. Unless there are some miraculous 11th hour changes regarding this system, the mountain is getting a period of rain, perhaps even a short period of heavy rain and thunderstorms. This is a powerful system that could very well bring blizzard conditions to portions of the Upper Midwest. The silver lining with this storm involves what is expected to be an eventual stalling this weekend over the Canadian Maritimes after the occlusion occurs. This sets the stage for several days of snow showers capable of yielding accumulations over a multi-day period

Saturday, December 15, 2012

Lots of storminess, lots of precipitation types

As they like to say, let the games begin !!! In what should be one of the more active weeks of weather this calendar year, the region will see a bit of everything. The news is not all good but there is certainly plenty of news and after what should be a true roller coaster ride of weather conditions through Christmas Eve, the mountain should be much closer to an opening.

As of Saturday afternoon, there were not too many places in the U.S. that were seeing below-freezing temperatures but interior New England was one of those places. The culprit was a decaying but at one time quite intense piece of Arctic air centered over Quebec. The cold, dry airmass slipped into the region just ahead of the first round of precipitation expected to arrive in the form of snow during the middle of the day Sunday. I know the weather forecasts for Sunday have been all over the map and even as of now, models have yet to agree completely on a precipitation type through Sunday night. Various forecast sources seemed to have formed a consensus (that I agree with)  calling for a period of snow through Sunday night. The snowfall intensity will be mainly in the light to occasionally moderate range allowing for snowfall totals to to be in the modest 2-5 inch range. With temperatures only a few degrees away from the freezing mark, snowfall will generally be wet.

4 days ago, we discussed a second and more vigorous piece of upper air energy which will act as a potent steroid (for lack of a better word) in this whole weather situation. The upper air support, described in the meteorology community as a "shortwave", will commence its impact early Tuesday. Prior to this, the loosely entrenched area of cold weather over New England will continue battling it out with a push of milder weather from the south. The result will be the periodic continuation of either mixed precipitation or snow depending on what package of model guidance you believe. For the most part however, temperatures should stay at or below freezing in spite of whatever precipation falls Monday. This vigorous injection of upper air support will unfortunately begin to tilt the scale of this cold vs warm battle in the wrong direction. This is a situation I discussed somewhat in the previous update. As exciting as some of these amplifications look in a medium range model, and as much upside potential in terms of snowfall they can bring, the lack of a reliable supply of cold air can lead to some lousy results, especially early in the season. In this case, we will see an exploding area of precipitation Tuesday probably get wasted as cold air slowly gets scoured out of northern Vermont allowing for a period of rain Tuesday. This remains a tenuous situation and a few slight changes in the evolution of Tuesday's system could yield a different result. The storms amplification will ultimately allow colder temperatures and some snow to return for Wednesday although temperatures will remain near to just below the freezing mark through Wednesday and into Thursday.

When it comes to weather, it seems everything comes in streaks. It is largely analogous to a baseball player who has hitting slumps and periods when he hits lots home runs in a short period of time. The upcoming period can certainly be described this way. After the the snow, mixed precipitation and rain in the Sunday-Tuesday time frame, another even feistier weather system will move out of the Rockies and into the Plains and Midwest Wednesday into Thursday. This is yet another system capable of amplifying the jet stream in a profound way but do so with only limited cold air and probably do so too early. By Thursday evening, cities like Chicago north through much of Wisconsin could see near blizzard conditions if some of the medium range models are correct, but an amplification so far to the west allows warmer temperatures and rain to again threaten New England for a period beginning Thursday night or during the day Friday. Fortunately this situation is fluid and the ridging in eastern Canada will prevent this storm from tracking too far into the Canadian provinces before transferring some of its energy to the New England coast. This means that rain will turn to snow and snow showers and could persist through the weekend into Christmas Eve with some significant snowfall accumulations and colder temperatures. By the end of all the storminess, there should be a good amount of snow on the mountain and hopefully we have an opening day in our sights.

The end of 2012 should continue to feature temperatures that are in the above normal category but not excessively so. A few runs of the European ensembles have indicated a storm around the time of the 27th and 28th. That weather system is a long way off still but has promise at least as of now. The pattern as a whole should continue to be a ruled by a ridge in the west-central Pacific (near the dateline) and a ridge in eastern or central Canada. This is not the most ideal situation in the world but it is not totally adverse either. We have yet to see anything resembling an upper ridge in the western part of Canada which is necessary for a sustained outbreak of arctic cold and below normal temperatures.

Tuesday, December 11, 2012

Winter storm speculation begins

Exciting times have finally arrived making the colder weather feel that much more invigorating. Finally, we have storms (plural) to discuss and real winter weather to talk about. Lets also preface some of the details by saying that it is especially nice to see a succession model guidance cycles trend colder and snowier as opposed to what dominated last years SCWB headlines - warmer and rainier or just warmer and warmer.

Over the next five days there will be two important big picture developments. The first and I will say critical, is the westward progression of the "evil empire" in the Pacific. This large and destructive ridge will move west toward the date line and will allow the onslaught of storminess to shift south. The second is the westward movement and enhancement of a large upper ridge, almost a block, across eastern Quebec, Newfoundland and Labrador. Although this combination doesn't necessarily encourage widespread very cold weather, it does promote an active and southern storm track capable of producing moist systems which can ultimately get trapped along the New England coast or in the Canadian Maritimes. This is precisely what we can expect with the weather as we head toward next week. We still have significant concerns regarding the amount of available cold air but we are headed in the right direction and lets hope this continues.

This is a one-two punch scenario with the first system tracking through the plains and Midwest this weekend as cold air across Canada weakens with the remaining chunk settling over Quebec. The building ridge over eastern Canada will allow this lingering cold to ooze south ahead of the approaching initial weather system and it looks for now that potential precipitation should begin as snow Sunday evening the 16th. With several days still remaining before the start of this potential weather situation, a lot can still change, but there are good indications of a healthy moist conveyor with this initial system that could allow for an extended period of light to moderate snows into Monday. Such a scenario would certainly mean the first real significant accumulation of snow for the winter were it to hold.

The second part of the one-two punch is a much more dynamic system and could involve a large east coast amplification Tuesday into Wednesday (18th-19th). I consider this type of system a high risk/high reward event at this point because the potential, given an absolute ideal situation is for a massive snowfall. The risk however is that when such a powerful amplification occurs, with minimal cold air, so close to the warm Atlantic, there is little resistance to the eventual envelopment of warm air and a transition to rain. For now, I will be happy to see this first system evolve in the way it is forecast to evolve right now and hope the powerful ridge in eastern Canada works to flatten out this second storm somewhat,

Aside from the potential over-amplification next week, there are fewer if any threats for warm weather going forward to Christmas. The pattern does not support below normal temperatures but for the most part, respectable temperatures through Christmas day consisting of generally below freezing temperatures, at least in the high country.  

Monday, December 10, 2012

Another week of generally uninteresting weather but what about after ?

The sleet, freezing rain and rain will all be a memory as of Monday evening and this leaves us waiting and hoping for some good news before the holiday. Unfortunately it will not come from the "third wave" of low pressure, which will confine its impact to coastal communities Wednesday. We will see a few days of seasonable temperatures, generally below freezing but no major snowfall. Meanwhile, the cold weather will continue to intensify across Canada and act to freeze the Hudson Bay entirely within a few days - certainly a good development and the earliest freeze since 2007. The "evil empire" or the east-central Pacific Ocean upper ridge however will be the dominant player on our playing field and because of this, the bitterly cold arctic air will be forced more east rather than south and will have a difficult time being a major force in Vermont's weather over the next week.

As indicated in previous posts, another mild push of air will impact the region late in the week and into the weekend. The trend over the last few cycles of model runs has actually been a good one, lessening the intensity of the mild weather during the upcoming weekend and even hinting at a little pushback from colder air in eastern Canada. The concern however relates to the first in what should be a series of storm systems after December 16th. This first storm system is not likely to take a very favorable track and we might do best just hoping for a flatter, weaker storm that comes and goes with little notoriety.  A stronger storm system, like the one the last European model is showing, is likely to bring another round of sleet, freezing rain and rain and perhaps a lot of it.

As we move beyond next weekend, it gets much more interesting. The "evil empire" shifts west allowing the jet stream in the eastern Pacific to weaken and the storm track as a whole to shift south. Meanwhile the ridge and potential block across Greenland should finally give us a long awaited assist. This feature should help to keep the NAO negative and keep things active and intriguing along the east coast. There are indications of at least two major storm systems between the 17th and Christmas Day and one or both could yield some significant snows, at least somewhere. There will be ongoing concern regarding the amount of available cold air by then. Much of what is so available now, will be scoured out of Canada by the 17th so we potentially could use some help in that department.


Thursday, December 6, 2012

Storminess on the way, just not exactly how we would want it

Although not under the most ideal circumstances, there is some very active weather on the immediate horizon. The storminess will stem from what will be a highly amplified jet stream and all the ingredients that typically come with it like mild and moist air from the Gulf of Mexico and Arctic chill from Canada. I was almost expecting that a massive storm would be churned up out of all this; but were that to happen in this set up, it would suck very mild weather deep into interior New England. Instead of one big storm however. this massive baraclinic zone will produce not one, but two and quite possibly three separate storm systems. Cold air is in short supply but it's better than no supply.

The first and weakest of the series of potential weather systems arrives Saturday into a stale and deteriorating airmass. Precipitation will mostly occur early Saturday and will be in the form of rain with a few pockets of freezing rain. As completely useless as this weather system would seem, its passage will help allow some arctic air to jam its way into the Green and White Mountains in spite of a very adverse upper air weather pattern. The cold will arrive late Saturday and will be firmly in place on Sunday as the next system gathers strength in the Great Lakes and tracks toward the St Lawrence Valley. This track, unless it changes, will make it tough for any significant to snow fall when precipitation recommences Monday, but a period of mixed precipitation including a little snow is becoming likely. Ultimately, the mild push of air later Monday could prove to be too much and change all precipitation to rain but we could see some significant icing and if we are lucky, a nice base layer of concrete to build on. I had mentioned the possibility of a third wave in this series. Such a storm would be more of a snow producer Tuesday into Wednesday. Most of the model guidance has downplayed this possibility but the most recent run of the Euro showed some support for this.

Ensembles continue to show hints of another warm up beginning around the 13th of the month and persisting for a few days. The constant pushes of warmth still stem from Pacific ridge or the "evil empire" as we have been calling it. This ridge will migrate westward and set up an interesting dichotomy as we proceed toward Christmas with the PNA and NAO contradicting each other. With the Pacific ridge out of play however, the door will open for Arctic air to make its way into the northern part of the country and for the storm track to get pushed well to the south. In the end, some very positive developments should result. Stay tuned.


Tuesday, December 4, 2012

Weather to remain on the milder side through mid-December

I do not have the news most were looking for 3 weeks before Christmas. The dominant chess piece through mid-December will indeed be the upper air ridge in the mid-latitude Pacific. This will make life very difficult for those of us hoping for some good early skiing this December. I had hoped that other pieces on the chess board might mitigate the pain but we will instead be forced to deal with a few rounds of milder weather, rain and a minimal build-up of snow through the next 10-12 days. This is not to say that wintry weather is completely out of the picture through this period. The storm I had alluded to in the previous post could still provide a bit of that Monday, but that is a best case scenario at this point.

Temperatures should get a little closer to seasonable levels late this week but only for about 36-48 hours. Thereafter, another surge of milder temperatures is expected as the pattern turns more meridional. This essentially means that colder weather advances south across the western half country while the milder weather pushes north across the eastern United States. There will be a rather intense clash of airmasses in between which sets the stage for some very active weather across the Midwest this weekend into early next week. Interior New England could also be a part of this clash if we can get a little push-back from the building cold across Canada. This is a big "if" right now however and I would expect more in the way of rain or perhaps some freezing rain Saturday from the first wave of low pressure. The second wave brings precipitation late Sunday or Monday and could have a bit more cold air to work with but only in a very limited variety. Snow or mixed precipitation is a bit more likely in this period but the models have been trending toward this warmer scenario I have been detailing and we would need to reverse this soon if we were to get any love from this.

Temperatures will turn colder for a brief time during the middle of next week but the pattern will fail to break down. In fact, a vigorous disturbance over the Yukon will drop south and re-invigorate the trough over the western states. This is one of those really unwanted byproducts of what we should refer to as the "evil empire" or the mid-latitude Pacific upper ridge. As a result, we should see another round of milder temperatures between the 13th-16th of the month. After that, there is some evidence that the "evil empire" will migrate northwestward allowing the Pacific Jet to loosen somewhat. There is even some evidence of some splitting in the flow and would thus make it considerably more interesting right around the time of the holiday.

Sorry about the crap news. It is very east to lose heart especially after a year like 2011-2012 but it's very early and there are plenty of reasons to remain optimistic. If we get another 10 days of lousy weather we might as well get it now because it can be much more disruptive once the season begins.


Saturday, December 1, 2012

Competing forces battle for control of Vermont's weather after the eary month thaw

After a nibble of the white stuff and a bigger taste of some single digit temperatures, the mountain will be forced to endure a significant stretch of above freezing temperatures and some rain. All of this has been in the cards for some time so there is nothing too surprising or alarming. All of the big questions and potential concerns relate to the period beyond Thursday. There are reasons to be optimistic but there are also reasons to be nervous. The weather pattern confronting the region involves many competing variables and which ever one wins the day will largely determine whether or not the mountain can be set up with an early opening.

It's not worth spending significant amounts of time on what amounts to a meaningless thaw. Temperatures should surge into the 50's Tuesday and the combination of mild weather and rain Tuesday night should essentially wipe out most of the snow below 3,000 feet.


More seasonable temperatures and even a bit of terrain-induced snow should prevail later in the week which is where much of the uncertainty exists in our forecast timeline. As mentioned there are competing features on our playing field. The big concern, at least from my vantage point, is that the medium range ensembles are showing the return of the dreaded upper ridge in the east-central Pacific. My personal loathing for this feature has been on full display for well over a year now and my reaction is a mix of both dismay and skepticism. The preseason prognostication mentioned that the ridging in the mid-latitude Pacific has really not been an issue this fall and the disappearance of La Nina certainly discourages its development this year, at least for an extended period of time. Yes, it still could prove to be another tease, but we have to be honest, such a feature works to tighten the jet in the pacific, encourage zonal flow, and all but eliminate the ability of cold air to sustain its coverage of mid-latitude geography over the eastern United States.

There is a brighter side of this possibility spectrum so I hope I have not completely killed the mood. The hemispheric picture consists of much more than a east-central Pacific ridge. In fact, there is clear evidence of ridging in the Jet Stream extending from the Aleutian Islands northward over the north pole and southward to Greenland and the Davis Strait. Essentially, the ridging forms a ring-around-the-rosie encompassing an area of very cold air across Alaska and western and central Canada. The cold has allowed for a rapid expansion of snow and ice across North America as a whole and most importantly for us, the Hudson Bay. Look at the coverage of ice on the Hudson Bay this year compared to the last 5.

2012 - http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2012/ims2012335_alaska.gif

2011 - http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2011/ims2011335_alaska.gif

2010 - http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2010/ims2010335_alaska.gif

2009 - http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2009/ims2009335_alaska.gif

2008 - http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2008/ims2008335_alaska.gif

The freezing of this large body of water, and freezing it early is monumental in getting a good build up of cold over eastern Canada so it ultimately can become an asset in our crucial winter weather scenarios.

Cold weather across Canada is not the only reason to be optimistic. The two major ensemble packages largely disagree with one another on how this all plays out by next weekend. The American GFS package depicts a scenario that hinges on the aforementioned Pacific feature. Two additional and significant surges of milder weather are likely in such a pattern which would be dominated by a negative PNA and more minimal high-latitude blocking. The European package paints a much more optimistic evolution which would have cold weather returning by the end of next weekend and remaining in place for an extended period there after. This set-up hinges more on what is indicated to be a negative AO and a broader extended reach of the bitter chill across Canada. Most interestingly, the European also depicts the potential for our first major snow producer around the 10th of the month. We have not seen evidence of such a storm until today we would love to see it.

I thought it was interesting to see how similar this year is matching 1984-1985. November of 1984 was a touch below normal on the east coast (same as this year) but more significantly below across western Canada, much like this year. The December that followed featured cold weather across the U.S. and mild weather covering much of the east coast, much like the GFS ensemble depicts. The ensuing January was then bitterly cold featuring the coldest Presidential Inauguration ever recorded when Ronald Reagan was sworn in for his second term. I am closely watching how this plays out, and whether we continue to follow the 1984 scenario in accordance with the American ensemble or whether we diverge like the European suggests.

Saturday, November 24, 2012

Winter-like temps for the upcoming week

There were some logistical changes and notes that were left unmentioned in the SCWB's preseason commencement. First, I think the new twitter timeline up on top is a little "noisy" and I prefer the old timeline that was used last year. Twitter seems to have cracked down down on the use of third party apps on Blogger sites leaving me little choice. We could eliminate the timeline entirely but I actually like the idea of it and will work to clean it up a bit if I can. The "favorability index" has been traditionally explained at the beginning of the year but I always get questions throughout the season regarding the index so I will leave the explanation on the right side of the blog. Plenty of readers have also suggested building a glossary. I have unintentionally ignored all those requests though it's a great idea and I may work to create one this year.

Winter has arrived in Vermont and snowflakes are flying up and down the spine of the Green Mountains. The pattern is being anchored by a powerful high latitude blocking structure near the Aleutian Islands along with a smaller one in the northern half of Greenland. This has allowed a broad area of cold to settle across Canada and finally make an entrance into the U.S. during the Thanksgiving holiday. The cold will provide the region with a healthy taste of winter and it should persist through the week. High terrain such as Mad River Glen should generally see temperatures remain below freezing for most of the upcoming week which might be normal by late December but is still a bit unusual in late November.

There are about 3 different disturbances throughout the upcoming week that are capable of providing at least flurries and at most a light accumulation of snow. A more organized storm system will exit the eastern Rockies and move east Sunday. This system will have a difficult time phasing with the various pieces of aforementioned and weaker polar disturbances and as a result, much of the moisture with this storm may stay to the regions south. These things do have a way of changing however and we will keep watching. Were it to happen, significant snowfall would occur this Tuesday the 27th, but the chances are low right now.

The chill will erode very slowly during the early part of December and the more medium range ensembles suggest a 2-4 day spell of warmer than average temperatures during the first full week of month. This time of the year, it could translate into a thaw and perhaps some rain before winter-like temperatures return. Throughout this period, the negative NAO-AO pairing will remain in tact and should promote a quick return to colder temperatures and additional chances for snow after December 5th. 

Wednesday, November 21, 2012

El Nino teases, but stays away from what should be a much colder 2012-2013 !!!

Welcome back!!! I doubt we can start too early this year. Last year's debauchery left many of us, me included, powder starved through the summer. Needless to say there has also been plenty of weather to talk about. Hurricane turned Superstorm Sandy was merciful on Vermont but historically destructive for the New Jersey and New York coastline. This was followed by an early nor'easter and accumulating snow in some areas that as of now are still recovering. For the tri-state area readers, hopefully some sense of normalcy has returned. I can tell you, Vermont can certainly feel your pain a little more than one year removed from Irene.  

The Big Picture

The broader weather picture has been interesting to follow as always. The excessive warmth and in some areas drought continued through a good part of the summer. Beginning in August however, the warmth across much of North American finally abated and some areas, particularly across the center of the country, have actually seen some significant periods of below normal temperatures. This of course is fairly typical for most years but the first half of 2012 was so historically warm that the contiguous United States saw the warmest consecutive 12-month period on record. Sustained cold of any kind was nearly extinct and the area around the Great Lakes saw 2 months where temperatures were 3-4 standard deviations above normal in a 4-month period. The end of the excessive and rampant warmth across North America marked a large scale behavioral shift in the weather across the mid-latitudes of the northern hemisphere. The change can be attributed to a variety of factors but the Arctic Oscillation would seem to be the prevailing force since it abruptly shifted from positive to negative during the middle to later part of the summer. In addition, the autumn months have featured more frequent high latitude blocking events, the biggest and most consequential was the block over lower Greenland which provided the steering mechanism that guided Superstorm Sandy into New Jersey as opposed to turning out to sea.

 ENSO - La Nina or El Nino or nothing

Regarding the upcoming winter, the early expectations largely hinged on what was expected to be a developing El Nino. Some forecasts had a significant El Nino developing by late autumn. As it turned out the upcoming El Nino was a lot of "huff and puff" and amounted to nothing more than a big tease. Yes, a few forecasts still have a weak ENSO event during the winter months and yes, sea surface temperature anomalies have crossed the "0" line, but they are not significant. As of now, the most noteworthy aspect of the ENSO situation would be the disappearance of the La Nina which presided over the previous two winters. I want to expand on this fact later in what I think further justifies some of my optimism about the coming months. Regarding the ENSO, the quick summary this winter is that we are expected to be close to neutral.

The bigger story - PDO  
 
The prevailing variable as opposed to ENSO appears to be the Pacific Decadal Oscillation or PDO. The index describes the configuration of sea surface temperatures across a broader swath of the Pacific Ocean as opposed to just the equator. A negative index is what I refer to as the "blue horseshoe" since it consists of horseshoe shaped ribbon of cold temperature anomalies enclosing a broad area of warm sea surface temperatures anomalies in the central Pacific. This autumn has featured one of the strongest negative indices going back 50 years and this sets up a very interesting dichotomy. A strongly negative PDO which lends support to a La Nina contradicts the trends in equatorial sea surface temperatures which have gradually slid toward neutral and is now levitating at just above zero. From here the task is to find a few winters that have jointly featured a relatively neutral ENSO and a very negative PDO in hopes of discerning a pattern. This proves to be a difficult chore since there a few winters with such a personality. 1994-1995 was essentially a 1-month winter (February) with the rest featuring mild weather and a lack of snow. A very negative PDO prevailed that winter along with a moderate El Nino. 1961-1962 was a relatively neutral ENSO winter with a very negative PDO and it was generally cold with average snowfall. Both winters are hardly a perfect match however since the 1994-95 ENSO was stronger than the current ENSO and the 1961-62 ENSO was tilted a bit more to the La Nino end of the pendulum though it was close to neutral. Other winters, particularly some good ones in the late 60’s have had some loose similarities but are far from good scientific matches. To say the least, the weak ENSO, strongly negative PDO dichotomy is quite inconclusive. Separately the strongly negative PDO favors troughiness and cold in the western United States while the weaker ENSO generally favors frequent blasts of rather intense cold throughout the United States. Many of the big negative PDO winters however have a significant La Nina as a companion thus clouding such cause and effect judgements. It could certainly be argued; however, that although the above favors colder weather relative to last year, the pattern will be fluid with favorable stretches for skiers in New England followed by favorable stretches for skiers out west.

Snow and ice make a recovery

If one is to thus reserve judgement on the basis of the above two factors, it is time to move on to a third - the snow and ice situation. I know many readers consider themselves closet weather enthusiasts and might have read about ice in the arctic regions decaying to the lowest total coverage ever recorded in September. By late summer, a majority of the Arctic Ocean was open water and could have been open to shipping if such a route was desired. The process of re-freezing water involves the release of latent heat and disrupts the normal process of "cold air pooling" in the arctic regions. The "cold air pooling" is the process where continental polar, or arctic air strengthens and it is the opinion of many that the strength of these airmasses has already been significantly impacted by the changes in the ice coverage over the Arctic. In recent weeks, the arctic has re-frozen and seems to have recovered a bulk of its summer loss (though not all of it). In addition, ice has been forming in the Hudson Bay and the process of freezing that key body of water will occur faster this year verses some of the previous few. All of this has been helped by a rapid expansion of snow across the high latitudes this autumn and has helped the "cold air pooling" process by making up for the loss of ice in the Arctic. The total amount of northern hemisphere snow, measured in millions of square kilometers, ranked 8th in the last 44 years of recorded data in October. This is an impressive recovery since the summer months featured the lowest total coverage of northern hemisphere snow and ice. It is very encouraging behavioral sign leading up to our winter since a fast freeze of the Hudson Bay and a broader area of snow cover should allow the region to have easier and more effective access to arctic chill.

Has Mother Nature tipped her hand ??

 Lastly, I wanted to allude again to the recent behavioral trends in actual weather during the past few months. Often times, the weather pattern in autumn can exhibit characteristics or closely foreshadow events or patterns that will occur in the upcoming winter. On a larger scale however, I am most interested in contrasting some of these bigger trends year over year. At the end of last year, I had noted how destructive the upper level ridge in the mid-latitude Pacific was on the winter as a whole. Last year, this ridge feature was fueled by the prevailing La Nina, a generally positive Arctic Oscillation (AO) and a Madden-Julian Oscillation that never “cycled”. This year there has been virtually no evidence that such a feature will be a persistent problem. When there have been indications of an upper ridge in the central Pacific Ocean, it quickly breaks down or never develops as advertised. The second such trend, and one which may have a hand in the behavior of the first, is the AO and frequent appearance of blocking mechanisms at high latitudes. Such a trend could quickly reverse itself of course, but if the high latitude blocking continues as it has over the past 2-3 months, the winter will behave more similar to 2010-2011 and very different verses last year.

Summarized into a forecast

A winter forecast stemming from the first two more traditional variables would be a very cloudy inconclusive picture. The rapid expansion of snow and ice in the high latitude regions this fall combined with the recent behavioral trends in the Pacific Ocean and high latitude regions has me thinking this winter will be on the colder side. In the past several pre-season prognostications, I have generally biased the forecast toward the warmer side of the 30-degree average since it has been statistically unlikely to get a cold winter relative to this average in recent years. I am going to forecast “average” this year which may seem rather tame but relative to other pre-season forecasts and relative to a more recent 10-year average this is actually rather bold and quite cold. Snowfall I think will be a shade below normal mainly because I think it will be drier than normal. The basis for this comes from looking back at ENSO-neutral winters and seeing the trend toward drier than normal conditions over New England. In addition to this is recent trend across the area of drier than normal weather. In a sense, I am forecast a poorer man’s version of 2008-2009 which was a generally good winter, full of cold, but also full of some drier stretches of weather and periodic instances where snow and cold is confined to western North America. Quantitatively this translates into a total snowfall of 225-250 inches which is slightly below the 250-260 inch normal but much improved over last winter.

Enjoy your Thanksgiving feast with a pre-season pass !! The first threat for real snow comes during the middle of next week with some accompanying cold weather. More on that in the days ahead !!

Friday, March 30, 2012

Winter 2012 - The winter that wasn't

The record breaking weather that defined half of the month of March, making it the warmest in the last 120 years is over. The first two weeks of April will be more seasonable and with the AO having attained a negative footing, we may actually see an occasional taste of winter. At this point however, most of us have mentally tuned out of winter either refocusing on NCAA basketball or perhaps gardening since the warmth has certainly caused many of those to spring to life.

In the pre-season extravaganza of 2010-2011 I devoted a chunk of time discussing the split personality of La Nina winters in Vermont. We had highlighted several winters going back over the last 50 years which had illustrated how La Nina can be either feast or famine in northern Vermont. This point was obviously underscored during the past two winters. 2010-2011, although we did miss a few storms, was generally a strong winter featuring consistent cold weather and deep snow persisting well into April. 2011-2012 by way of comparison was a complete abomination. I thought we might avoid the embarrassing distinction of having to live through the warmest November to March period in northern Vermont (we were actually slightly colder than 2001-2002 through February), but then we got a March heatwave and what amounted to some of the most anomalous weather ever recorded in Vermont from a temperature standpoint. By the end of the month, the winter of 2011-2012 as defined by the period beginning in November and ending in March was rather easily the warmest ever recorded. From a snowfall standpoint the winter was close to being one of the worst ever. For many ski areas, the combination of lack of snow and outbreaks of above-freezing temperatures made it the worst ski season ever. Only a handful of winters can rival this past winter for lack of snow. Mad River Glen recorded about 150 inches of snow, 100 less than average. 1990-91, 88-89, and 79-80 were all similar. The lack of snow in 1979-80 brought the region some notoriety with the 1980 Olympics being held in Lake Placid. I have some pictures somewhere of crews frantically spreading artificial snow in preparation for the various Nordic skiing events that year. This year would have been similar but in many ways worse because of the added effect of the invariable relative warmth.

The explanation behind the massive failure of the 2011-2012 can be boiled down to a few key points. For a La Nina winter to achieve some success in Vermont, it needs the support of a negative AO for key stretches of the winter. We got such support for about two weeks in late January and early February. The average daily AO index from November to March was roughly a positive 0.9. I would have to do some further analysis on this data but a rough glance indicates that the standard deviation of these results going back 100 years is probably about a 0.5 or so making this years number very statistically significant. The 2010-2011 winter was approximately negative 0.4 while the incredibly "blocked" winter of 2009-2010 was well below a negative 1 (My other weathergeek friend is currently telling me the 09-10 winter featured the most negative AO ever recorded over this period). We might have been able to endure the lack of high latitude blocking in the jet stream but repeatedly this was coupled with a very tight and vigorous jet stream across the mid-latitude Pacific Ocean. Though the jet tightening can be partially attributed to the positive AO there are other contributing factors. The more obvious would be the presence of La Nina since the tight Pacific Jet is one of its defining characteristics. The other factor I have heard mentioned is the MJO or Madden-Julian Oscillation. This is the term used to describe the cycle of convection in lower latitude regions ranging from the Indian Ocean to the Atlantic. It is complicated but phases of the MJO are determined by areas of enhanced and suppressed convection in these regions. In this particular winter we went through an extended period of time where it was difficult to determine a phase. Specifically there was a glaring lack of tropical convection in the Pacific and no mechanism to either divide or loosen the torrent of flow in the Pacific that largely killed our winter. This was very evident in the ensemble data where it seemed impossible to breakdown the prevailing ridge which dominated the lower latitudes of the Pacific.

Finally, it is inevitable that those in the field will be asked about "global warming", "climate change" or whatever other trendy term is being used to describe the warming global temperatures trend that seems to have matched the beginning of the industrial revolution. More specifically though is how to place this recent winter in the context of global warming. My answer and advice to this is to try and avoid it. Statistical noise and variability that is location specific, even spanning the course of a season, is insignificant in this conversation and proves very underwhelming when looking at trends that include the entire globe. Extreme weather events when spoken of individually and in one location should also not be part of the conversation. Temperatures across the eastern half of the U.S. between November and March were in many areas the warmest ever recorded over that period. Across the globe however temperatures in January and February of 2012 were very similar to and perhaps even colder than 2011. In other words, the warmth this year was location specific and was not part of a upward global temperature trend upward. In addition, there are much more ambient factors in a season that will dictate the outcome of a winter in a "globally warmed" winter and one that isn't. In other words, this winter if dominated by the same ambient forces would have also been mild and void of snow in 1912 just as it was in 2012.

If one is to frame the above-question a little differently however and ask the following. Would 2011-2012 been less warm without the impacts of global warming ? This I would have to answer a little differently. The data demands it does. It is estimated that winters in Vermont since 1990 are about 2-degrees warmer than winters in the 100-years prior to 1990. It is as clear as night and day. Yes, the data is still location specific and even periods spanning 20-year increments can feature statistical noise, but not that much statistical noise. Standard deviations for temperatures data spanning of 5-month cold season are between a degree and a degree and a half. This means more than half of the winters after 1990 are beyond a full standard deviation above the statistical mean. These things don't occur by accident, they don't occur because one anomalous winter such as the recent winter is skewing the data. It is in this case that Vermont is part of a larger global trend toward warmer temperatures. It means that yes the 2011-2012 winter would have been warm regardless but was likely warmer because of the effects of global warming. It means that the winter of 2010-2011 would have been colder without the effects of global warming. Fortunately, at least so far, the warming that has been prevalent the last 20 years is not translating to less snow. There is no evidence as of now, to suggest that the trend toward warmer temperatures is also part of a trend toward less snow. Snowfall in Vermont has remained relatively consistent.

Anyway, that is enough for this year. Thanks again to the Mad River Glen & Vermont skiing community for again being such a great audience to talk weather with. I couldn't motivate myself to do this without all of you. It has been a tough stretch thanks to Hurricane Irene and the warm snowless winter but better times are ahead. Have a great summer !!!

Sunday, March 25, 2012

Ugly season undergoes total meltdown

Weather more typical of June perhaps even July struck MRG the lethal blow. It was perhaps the most anomalous stretch of temperatures I have seen in the last 20 years or so. Anyway temperatures are back on the downward trend and we are about to enter a stretch of dare I say, winter-like temperatures. It will start Monday with temperatures hovering near the freezing mark and then dropping to near 5 across the interior Vermont high country Monday night. Temperatures will climb back into the 40's during the middle to later part of the week but snow is possible over the weekend from what could evolve into a significant late season winter storm.

With the season ended, we won't spend too much time sorting through the drama. I will do a season wrap-up in the coming days and then call it a year.

Sunday, March 18, 2012

Amazing stretch of March warmth to gain even greater stature this week

Temperatures for the last week have averaged 12-15 degrees above normal, reaching the 60's twice and the 50's on 3 other occasions. Statistically, that is pretty remarkable but it will be surpassed in the coming days by another incredible stretch of warmth. I always think it is kind of silly to describe events as "record breaking" since there is a big distinction between "recorded history" which stretches back about 100-150 years and actual history which stretches back billions of years. More accurately, we can describe the coming days as weather more typical of early June, nearly 3 months from now. Temperatures will reach the 70's in low lying areas on three successive days beginning Tuesday. These types of temperatures will not only end the ski season prematurely but it will likely initiate the 2012 growing season a good month before last year.

March is most certainly an "anything goes" type of period in the calendar. Many times, March is the highlight of the ski season with winter storms providing big time powder and average bases often times peaking in the middle to later part of the month. In 1998 we had a few big dumps in late February and early March. Toward the end of the month we had a similar push of warmth which brought temperatures to 75 on successive days and I remember skiing "chute" in shorts. Unfortunately, the warmth has already done a number on the limited snow in Vermont but shorts is nonetheless the advised attire.

Cooler Canadian air will bring temperatures back into the 50's this upcoming Friday. This happens in front of a more organized weather system which will bring rain to the region Saturday. By Sunday, arctic air will return to the region and the period that follows (the last full week of March) could actually get a little winter-like.

Monday, March 12, 2012

Maritime air to finally slow the advance of Spring

The mild air has done a number on the snow cover in low lying areas. The remnants of winter 2012 are now confined to the high country. Where the snow remains, the skiing has been great from what I hear with warm sunshine providing some of the softest snow of the season.

The warm weather and sunshine combination is likely at an end this week. Clouds and rain will prevail for much of the day Tuesday and this precipitation could end as a little wet snow Tuesday night as cooler "maritime" air backdoors its way into interior New England. Much of the rest of the week will likely stay on the cloudy side and although temperatures will remain above freezing for the most part, readings should stay in the 30's and 40's. The next system will brings its moisture into the region Friday in the form of a cold rain (maybe some ice in the highest elevations).

The rain should clear out by midday Saturday and the clouds by Sunday. After that, temperatures will again turn very warm with the help of sunshine and wherever the snow remains, some good spring skiing could certainly be had. 60-degree temperatures are again possible next week before the mild pattern finally breaks down and gives way to an extended period of more typical March weather.

Thursday, March 8, 2012

A bit of powder for Saturday, believe it or not

This comes less than 48 hours after 60-degree temperatures at the base of MRG and it will come before another extended round of spring-like weather. In the meantime cold weather is interrupting an incredibly mild March pattern. It will be a fitting encore of sorts.

The system responsible for the Saturday powder will arrive late Friday. It is a rather vigorous piece of upper level energy but it will move in and move out very quickly and has limited moisture. After temperatures hover near the freezing mark on the mountain Friday, flurries and snow showers will begin during the evening and continue into the overnight. By Saturday morning, the snow will be over and out and be replaced by wind and a very modest bit of chill. Overall, we can expect to see between 3-6 inches of powder, enough for a few decent turns Saturday morning. Temperatures will remain below freezing through Saturday night but sunshine and southwesterly breezes will move readings into the 40's again on Sunday afternoon.

A back door front could bring some maritime air into Vermont next week keeping temperatures within ten degrees of normal. Other than that though it will be mild with temperatures reaching 50 on at least 2 days next week and a good chance for rain on Monday. The upper ridge responsible for all this is capable of bringing record breaking high temperatures to many areas. It is the strongest upper level feature in the northern hemisphere over the next 7-10 days and it will leave its mark and potentially end many ski seasons across the eastern United States.

Sunday, March 4, 2012

Cold weather to quickly give way to an early round of Spring

Cold weather returned to the mountain today but that is about as much positive news I have if your still hoping for snow. As far as winter weather is concerned, the pattern going forward is just putrid. Anchored mostly by a very positive AO and another tightening of the jet in the Pacific, the weather will turn spring-like on the mountain. Over the next 2 weeks we can expect 4-5 days where temperatures exceed 50 and probably one day where readings reach the 60 degree mark. It will be a very embarrassing way for the month to conduct itself since over the years we have been accustomed to some of our best powder days in March.

A clipper system rotating through the eastern North American trough was the one real chance for snow in the near term. This system however will travel well south of New England and spread some unusual snow to southern Virginia. The system will help maintain the generally below freezing temperatures through Wednesday morning but with the help of sunshine and strengthening southwesterly winds, temperatures Wednesday afternoon could approach 50 in valley locations. Thursday will also be very spring-like with readings surging well into the 50's at the base and into the 40's at the summits.

The first round of mild weather will be interrupted by the arrival of a cold front Thursday evening. This weather feature will bring a period of rain to the mountain followed by more seasonable temperatures for Friday. The mild weather will make a quick return however with 40 degree temperatures again possible by as early as Saturday afternoon and the latest Sunday. More 50-degree temperatures are then possible throughout next week. By that point, the unsettled weather will become focused on the west coast allowing a very large ridge to develop across the center of the country. Mild weather will thus dominate not only the east coast but a large section of the eastern two-thirds of the United States. If the ridge does shift to the central U.S. it could open the door for cooler temperatures to thwart the warm-up in northern New England for a few days next week. That however is about the only thing that could save us from a record-breaking March blow torch, one certainly capable of making a very pathetic 2011-2012 winter, a memory.

Friday, March 2, 2012

Some snow early Saturday Morning, big thaw looking more likely next week

The next weather system, with its big warm push of air will eventually bring some ice and then some rain on Saturday. The cold air however will be able to hold its ground just long enough for what could be a brief but significant burst of snow in the early morning hours Saturday. Significant enough for a few inches before the lifts start churning and since temperatures will remain close to the freezing mark Saturday morning, a few good turns could still be had. By the afternoon we should see temperatures soar in to the 40's and this will be accompanied by some rain.

Beyond Saturday the outlook has not changed too much. Much colder weather along with some snow showers will move back into Vermont Sunday and Monday. The snow showers could dust the mountain with a light accumulation but I would not expect much. After a dry and seasonable day Tuesday, the big thaw is looking more likely. So long as the base holds up, the spring skiing could be quite good. Fundamentally however, the pattern could not be much worse with the three major teleconnection indices aligning in a very unfavorable way. Even when the mild weather abates toward next weekend, a second round of very warm weather will be poised to make another big dent into the winter.

Tuesday, February 28, 2012

Upcoming storm will produce two powder days late this week

Now I understand town meeting day is a week from now (if I am not mistaken) so perhaps take a day Thursday or Friday and trade it for a few hours next Tuesday. This will be a storm we will want a piece of and not just because it is a nice looking system. The storm will precede a rough stretch of weather at MRG. It is in the best tradition of La Nina to produce an epic day and follow it up a few days later with big trouble.

The upcoming storm is not necessarily a well-organized, particularly intense, or clean looking system. Ultimately, like many garden variety northeast storms, there will be two low pressure center's. One system which intensifies off the Atlantic Coast and another gradually diminishing but nonetheless notable storm in the Great Lakes. The two will work together, kinda, to produce a long west-to-east overrunning zone. This overrunning surface is the key to this storm and it will act as the centerpiece for a moist conveyor which should cover interior New England for an extended period of time.

Radar Wednesday should show snow inching its way toward MRG but it will take its time in getting here. By evening, the flakes should start flying and will gradually intensify to occasionally moderate snow after dark. By Thursday morning we should have 3-5 inches to show for our efforts while snow continues for a good part of the day and even into Thursday evening and Thursday night. By Friday morning Snowfall totals should be in the 10-15 inch range. If I were to pick a day to ski, it would be Friday. Winds are not expected to be particularly strong Thursday but they will be out of the east and historically that has caused some issues on the Single. On Friday winds will diminish and the snow will diminish to a few flurries. I am sure both days will be winners no matter what is open and what isn't.

So I gave the good news first so now here is the rest. We have managed to keep it winter-like across Vermont for the past week even as the rest of the eastern seaboard enjoys a continuation of what has been a very mild winter. On Friday however, a storm will gather strength in the middle Mississippi Valley and make a huge charge northward. Consequently, mild air will also make a huge push northward out ahead of this storm. Temperatures may sneak above freezing Friday afternoon but I am not too worried about that. By Saturday however clouds and precipitation (not the good kind) will return to MRG. We may retain enough surface cold air to produce a period of freezing rain but that's about it. Eventually we are going to see some rain and temperatures that reach the 40's during the day Saturday. The cold front associated with this storm is a sharp one and winter will return Sunday along with snow showers. The instability in the wake of this system could allow for a light terrain induced accumulation Monday and then readings should stay below freezing through Wednesday morning.

Ensembles are starting to key in on a major thaw for the middle and back half of next week. We still have a little time to escape some of this but has the potential to be a real crusher with record breaking temperatures, maybe even 60's. The thaw would then culminate with a rain event later in the week. Also a crusher.

The moral of the story is pretty self explanatory. Get a piece of this storm !!

Sunday, February 26, 2012

More where that came from ?? Maybe a lot more

Sure !! sign me up. Its been a few days since the last update but not much has changed. Two systems will travel from the Rocky Mountains toward New England over the next 5 days or so. Both will be guided by a very typical La Nina upper level pattern. The first system, which should bring 1-2 inches to northern Vermont Monday, will not generate much excitement. This storm does not have significant amounts of moisture and its track up through the St Lawrence Valley is hardly ideal. It will however play an important role in the story and set the stage for a much more potent mid-week storm with lots of potential.

The Monday system, as it passes, will generate a critical confluence area in the jet stream over the Canadian Maritimes. A confluence area can be described as an area in the jet stream where wind speeds accelerate as one moves from west to east. Imagine traveling down a calm river in a kayak and suddenly encountering class 5 rapids. Its more or less like that. The mid-week system will move out of the Rocky Mountains Tuesday and threaten to follow the track of Monday's storm up the St Lawrence Valley. It being a stronger system, such a track would bring the threat of warmer temperatures and rain. The confluence zone will prevent such an occurrence and allow cold and dry Canadian air to establish itself over interior New England in advance of the clouds and the arrival of precipitation Wednesday. The result will thus be snow which should arrive Wednesday and persist through a good period of the day.

There are some questions regarding this storm even though I think the threat for rain and ice is greatly diminished as of Sunday morning. The various models show a varying degree of impact from this so called "right entrance" region of the jet stream. The European shows a profound impact and although it suggests a period of snow Wednesday, the snow is ultimately pushed south Thursday and total snowfalls would be in the lighter 2-5 inch territory. Other indications however show a much more significant period of snow and the possibility for a real "epic" style event. Snow would persist for a 24-hour plus period and could snowfall totals could approach 2-feet. It would be a heck of a way to start March.

Ironically, this is all happening as the teleconnection indices have all turned unfavorable. The pattern for much of the eastern seaboard south of New York city has been in fact very non winter-like. Washington D.C. is reaching 60 degrees it seems every day and parts of Virginia have seen readings approach 80. Much of this will continue through this week with a sharp divide between winter which will be confined to interior New England and spring which will continue to prevail in the Mid-Atlantic States. Looking out beyond the storm, this is shown to generally continue and there are continued threats for "thaws" and bouts of mild weather even across interior New England. So far this pattern has put us on the right side of the battle but we are living on the edge. If we strike gold with this storm Wednesday/Thursday take advantage of it because our good fortune might not hold up.

Thursday, February 23, 2012

Nice 6-12 inch snow event for the weekend

Even in a good year, La Nina can hang Vermont right on the edge. With this storm, like many others it is touch and go all the way to the finish line. Some you win and some you don't. With this one it looks like we come out on top. The storm in question will not intensify the way I thought it might a day or two ago. As a result it will be able to transfer its energy to the coast quicker thus stopping the flow of warm air at key levels of the lower troposphere.

I've looked at some of the latest data from the high resolution models which are shining some light on specifics. Precipitation will arrive in the form of snow and begin as early as noon Friday with temperatures within a few degrees of freezing. The snow could become moderate to fairly heavy for a time during the afternoon and accumulate a few inches before lift closing time. It could make for a decent afternoon of skiing if you can sneak one in. This initial wave of snow will actually taper to flurries during the evening. At this time, temperatures a few thousand feet up might still exceed the freezing mark opening the door for the possibility of some freezing drizzle or light sleet. At the surface however, temperatures will hover between 25 and 29 for much of the evening and the overnight. Around midnight, the second batch of good upward motion associated with the storm will arrive and the threat of freezing rain/sleet will be gone (I don't think we really see too much of that). Snow should re-commence and could become heavy in the pre-dawn hours. In the end, the heaviest snow will only persist for a few hours but it will be enough to blanket MRG with 6-12 inches of relatively dense powder. The critical temperatures for powdery vs wet snow is about 28 or 29 degrees (depending on a few variables) and base temperatures will be right there. Temps at mid-mountain and at the summit will support powder all the way through. Even after the heaviest snow is completed, lingering instability will allow terrain induced snow to persist through much of Saturday. It will be mostly light to occasionally moderate snow and enough for an additional 2-4 inches.

And for those heading up from those southern locales let me say this. Driving to Killington or Okemo may not get it done. Much better chance for a period of sleet or freezing rain in central and southern Vermont. If your going to make the drive, make it to MRG, the best place to be on a powder day without question !!!

The Rocky Mountains will actually spit out two additional weather systems over the next week. The first moves into the Great Lakes and up the St Lawrence Valley Monday night. This is a system that lacks moisture and will lose some of its dynamic support as it presses east which will prove to be a blessing since its track would suggest maybe a rain event if it were stronger. In the end, this has the makings of a light accumulation of snow if at all. The second system will generate a lot of discussion and will arrive Wednesday as a much more potent storm with plenty of moisture. Again, Vermont should be right on the edge and could see an icy mix, maybe some rain or maybe a big winter storm. I will call it the "Leap Year" storm since its arrival will be on Feb 29. We could go back to our 2012 ways and flame out on this event but we have the chance to score big so stay tuned.

Tuesday, February 21, 2012

Friday/Saturday weather system is the strongest to impact the region all month

It has been amazing to look at precipitation totals for the month of February and see many places struggling to reach a half an inch (liquid). If the region doesn't get more precipitation this month, it would certainly rank as one of the driest February's on record. Certainly another in a litany of wrong answers this winter. All of that said, MRG and the surrounding area will get the direct impact of the strongest, most organized system of the month later Friday into Saturday. The specifics remain a little uncertain, the precipitation type remains a little uncertain but we can try and clarify what we do know as of now.

Until Friday, the mountain will have to endure another mild stretch of weather. Both Wednesday and Thursday will feature above freezing temperatures. Thursday's weather however will be cloudy and I would expect a period light to moderate snow most likely in the morning. With temperatures in the low to mid 30's, this is going to be a wet snow, perhaps even rain in the immediate Mad River Valley but on the mountain a few inches is a reasonable expectation.

There will not be much cold air to work with as a storm system gathers strength and gathers moisture in the Midwest Thursday night. Temperatures will drop below freezing on the mountain by Friday morning and will hover a few degrees above freezing during the midday. When precipitation finally begins late in the day it will be pretty marginal. The dry air as the surface will help bring temperatures back below freezing as the precipitation intensity increases but conditions aloft could make this tough. An early look at cross sections suggests a period of sleet Friday evening and Friday night. The Tuesday evening run of the GFS though did show mostly snow however thus again offering its ray of hope in what has been a dark winter. The GFS has not performed well however and the weight of the overall pattern will make an all-snow event extremely difficult in my opinion. My guess right now is that after a burst of snow Friday evening, we will see an extended period of sleet and maybe some freezing rain. The best part of this storm is likely to be Saturday. As the system wraps up in the Canadian Martimes, it will allow a pool of instability to settle over the Green Mountains inviting both wrap-around and terrain induced snows to persist throughout the day. By Saturday temperatures will be a lot colder allowing any accumulation to be powder.

Saturday, February 18, 2012

A few inches here and a few inches there, it could be worse

A couple inches of snow certainly helped but it would have been nice to land that big one. We couldn't quite pull it off. Now La Nina is going to drive this train and do so in high gear. Temperatures will be on the mild side of average for the next 5 days or so but we should avoid an extended thaw. We should also see a series of weaker systems bring the chance for snow or mixed precipitation.

Both Sunday and Monday will feature dry weather and at least some sunshine, particularly Monday. Clouds should make a return later Tuesday in advance of the first of these aforementioned weather systems. It will not have a lot of moisture or cold air to work with but the push of mild weather also appears weaker than I had feared. Temperatures should sneak above freezing Tuesday afternoon and then hover around the freezing mark Tuesday night as light snow begins to fall. It will be another instance where wet snow falls over the low elevations while we get a more powdery accumulation near the summits. I don't expect much but we will take it where we can get it.

After a brief dry period later Wednesday, another system, with a little more moisture should bring what looks to be snow but possibly mixed precipitation to the region Thursday. These disturbances in the jet stream look like Alberta Clippers but they are getting propelled by the strong Gulf of Alaska ridge and intense jet in the eastern Pacific. The jet is also causing Pacific air to run much of the eastern part of the country over, thus the mild weather. Fortunately though we are not seeing a strong southeast U.S. ridge and thus we avoid the big thaw. With Thursday's system, temperatures will again be close to freezing. If we don't get precipitation to mix with sleet or freezing rain we could certainly see a few inches.

The last weekend in February into the following week looks extremely changeable. That is saying a lot since New England in February/March is typically very volatile. The good news involves the weekend. Ensembles are now all on board suggesting a major eastern U.S. trough amplification. It actually caught me a bit by surprise to see what appears to be a major and widespread shot of arctic cold interrupting a mediocre pattern. In addition, the third in a series of these weaker weather systems could again spread snow or mixed precipitation into the region either Friday or Friday night. This "third" system may actually get ignited somewhat by the amplifying upper air pattern and strengthen past the "weak" stage.

Cold weather should dominate for much of the weekend but it will be temporary in nature. An amplifying trough in the western half of the U.S. will result in a mild push of weather in the last few days of February that will be hard to fend off. This should also be temporary but it result in a bit of rain. We have managed to avoid that for much of the month believe it or not.

Wednesday, February 15, 2012

Let the rumor mill turn !!!

Here we go !! Big holiday weekend only days away and the high drama begins in VT. And yes, the snow event for Thursday night is still on the calendar. This is not an aesthetically appealing system on the weather map. It is the first in a series of events resulting from split flow in the jet stream. In the end however, it will never become a very organized storm and the light snow Thursday night into early Friday morning will total between 2 and 5 inches. Temperatures at the base of the mountain will also be close to freezing giving the snow a wetter consistency. Higher elevations should see some decent powder.

If Thursday night's storm is "beer in a shot glass" then the storm Sunday can be described as the "full keg". Its all about the split flow in the jet performing its normal tasks. Energy rotating through the southern branch of the jet early in the weekend will begin sucking moisture out of the Gulf Saturday. By early Sunday, a major winter storm will be moving northeast out of the southern states and toward the east coast. 3 Successive runs of the American GFS model complete the proverbial "bomb" with this storm, rapidly deepening the system as it tracks close to Long Island and over Cape Cod. Heavy snow, high winds, the whole gamut would be the result for later Sunday and Sunday night. Hypothetical snowfall totals ? well I think one can get the drift, no pun intended.

The reality, even without the repeated frustrations that have been so prevalent this winter, is this. The consensus of model guidance still takes this amazing looking weather system too far out to sea. The Canadian model is not so subtle by suggesting, "what storm?". The European shows a nice looking storm moving from the Gulf Coast to the Virginia Tidewater area, but the storm never takes a critical northward turn up the coast and rides innocently out into the Atlantic bringing rain and snow to areas much farther south. Even some of the American GFS ensemble members seem to suggest some internal strife in model-land. Interestingly, I have been told the GFS has recently had a "physics" upgrade which we all hope will improve the performance of a model that has performed quite bad this winter. It will have an early chance to prove its worth this weekend.

It is really just a timing question at this point. A clipper system is rotating through the Great Lakes just as this massive Gulf storm is strengthening. The American model is moving the southern energy along more efficiently allowing the upper air support from the clipper to inject its energy from behind, the we would prefer it. By moving the southern stream energy slower, the European shows the clipper system moving atop the Gulf storm, thus making it more difficult for the storm to make the northward turn. This is certainly a potentially big event and worth watching but the chances for big snow are still less than 50 percent right now. What was that line Jim Carrey unleashed in Dumb and Dumber ? "So your saying there's a chance".

Beyond Sunday La Nina will try and show its dark side again. One and perhaps two pushes of mild weather could impact the region between the middle of next week and the weekend of the 25th and 26th. It is still possible much of the mild air is confined to the Mid Atlantic and southeastern states so we will just wait and see.

So we found out today that there are organizations out making a concerted effort to poison the global warming debate with propaganda. The goal ? Plant the seeds of doubt and hope the garden grows. It worked, it seems half the country's political establishment feels the issue isn't even credible. The science is crap they say, look at what happened with climate-gate, the data was manipulated. Funny because if it doesn't come form a misguided politician, it comes from shadowy places and dark alleyways. Never does it actually come from a credible scientific group who are actually willing to go on the record with serious contradictory evidence. Well now, one of those dark alleyways got illuminated.

http://www.nytimes.com/2012/02/16/science/earth/in-heartland-institute-leak-a-plan-to-discredit-climate-teaching.html

There is nothing wrong with being a skeptic and be cynical of the aggressive assertions made by the climate science community. I know plenty of people in my own circle who wear that with pride. To brush the issue aside as non-credible is just plain silly. Certain political leaders should be wasting less time trying to undermine climate scientists and more time assessing the actual risks involved with climate change and devising policies to deal with it accordingly. It isn't just about whether or not you like Al Gore, the stakes are much higher.

Monday, February 13, 2012

3 precipitation producers in the next week should keep it interesting

It hardly looks like the ideal weather pattern but it will be an active one with plenty to blog about over the next week or so including three potential weather producers. Its still a few days from our first shot for snow and we have already seen most of the cold from the past weekend move out. Clouds should keep temperatures close to the freezing mark both Tuesday and Wednesday and flurries or a period of light snow could fall from those clouds later Tuesday into Tuesday night. Any sun on Thursday will also give way to clouds in advance of the first discussion-worthy system. This storm has very little cold air to work with but its attempt at making a run up the St Lawrence Valley will get thwarted when the Atlantic Coast, as it often does, magnetically pulls much of the system's energy to the coast. This process is one of the reasons why interior New England can be such an ideal location for snow from east coast storms. At least that is the case during most years.

Precipitation should begin as snow but with temperatures within a few degrees of freezing it could be on the gloppy side at lower elevations. Snow should continue into Friday morning with accumulations in the 4-8 inch range. Glop or powder, the snow will obviously be very welcome prior to what is a big holiday weekend. The "Ski the East" boys are looking to do the Unconventional Terrain Competition this Saturday so hopefully the Friday morning event is enough to make that a success.

A less aggressive east coast trough amplification this weekend will ensure seasonable temperatures through President's day. There is also a clipper system rotating through the Great Lakes which could provide at least a light accumulation of snow Saturday night into Sunday morning. This would be the soft bigotry of low expectations. It is worth mentioning "The Gulf", the buildup of moisture down there and what could ultimately result in a storm riding up the east coast. The storm would be advancing up the coast as the clipper is spreading its limited clouds and moisture in to the northeast. The general consensus is still to take this system too far away from the coast for a big interior New England hit. Its worth keeping an eye on though.

In the wake of this strengthening storm (offshore or not) we should see a reenforcing shot of cold for Sunday and Monday and some of the better skiing of the season. The AO however will be neutralized by early next week and with the emergence of a large "La Nina-like" Gulf of Alaska upper ridge, much of the best action will shift into the west. The first weather system that results from this pattern could therefore be a rough one for us with ice and rain included in the package. In past years however we have seen these patterns go both ways. Some have been a debacle consisting of rain and warm weather. Others have actually been quite good with some of the best snow falling over Vermont. We can guarantee that the skiing will quite bad further south as very warm weather could grip a large portion of the Mid-Atlantic and Southeast.

Saturday, February 11, 2012

Another weekend without much snow, time to focus on the next one late in the upcoming week

I have began the process of emotionally detaching myself from this 2012 winter. It is a necessary evil at this point and it is being done to preserve my mental health. We were hopeful that the current pattern which has most of the ingredients necessary to bring us away from these dark times has not come through. We got some bitterly cold weather which will persist through the weekend, we got a few inches of snow, but I had hoped for one of those 30-40 inch weeks. It never happened.

The polar vortex will gradually rotate out of southeastern Canada early in the upcoming week and temperatures will begin a slow moderation. For the first time this winter, we have legitimate split flow in the jet stream. This stems from energy in the jet stream undercutting the deteriorating ridge in western North America. We just can't get enough split flow and I want to say I am happy to see it, even for a little while, but remember I am not making the emotional investment. It's just not worth it. That being said, a significant weather producer will move from the Rockies into the Plains Wednesday. We will be running low on cold weather by then. Temperatures Tuesday and Wednesday might even sneak above freezing during the afternoon (although overnights should remain chilly). By Thursday clouds should arrive and precipitation should follow either later in the day or at night. What happens from there depends on a few different variables most important of which is the track of this storm. Right now the system appears as it it wants to make a run at the eastern Great Lakes but transition its energy to the coast. This would bring some decent snows to the region but lets just wait and set ourselves up for another big disappointment.

The storm's energy is significant energy enough to yank down some Canadian chill. Much of Canada will in fact be free of arctic air by next weekend meaning that temperatures will be seasonable but considerably warmer than the current weekend. This is the all important president's day holiday which should be free of any rain, free of any bitter cold, hopefully have at least some fresh snow from Thursday's system and perhaps some additional snow from any weak disturbance in the jet stream or some simple terrain enhancement.

The "classic" La Nina structure of the jet stream which is expected to take shape by next weekend will have the effect of re-positioning a lot of the action out west by the 20th of the month. I think next weekend into president's day is safe. Beyond that however all bets are off. Are we going to preserve enough of the high latitude blocking either across the North Atlantic or the Polar regions to thwart another big thaw ? Maybe. It's disconcerting but the only thing we can do at this point is to lower expectations and write off any rain event as a byproduct of a very bad winter.

Wednesday, February 8, 2012

Light snow Saturday, bigger storm still a long shot

Our attention is now focused on the weekend, a Polar Vortex and a clipper system. The European model has been the lone sailor showing that this system tries to blow up south of Long Island and potentially bring some significant snows to New England. Even the Euro has been a bit fickle with this system however and has yet to provide details with any consistency. Personally I am having doubts about this potential storm. The "PV" can be a very overwhelming feature consisting of very strong winds at jet stream level which often act to guide East Coast systems out to sea before they attain any real strength. Nevertheless, the clipper itself, even without the support of Atlantic moisture, can deliver the mountain a few inches of snow Friday night. It will be a very cold weekend, one of the coldest of the season with well below zero wind chills Saturday and a few nights of well below zero actual temperatures through Monday.

We are going to lose the support of the AO in roughly a week and the pattern will transition into a more traditional La Nina looking set-up. A large ridge across the Gulf of Alaska, a trough and unsettled weather over much of the west, warm weather in the southeast U.S. and a big question mark for New England. Actually the question mark relates to what should be a significant weather system that arrives between the 15th and 17th of the month. The breakdown of the "negative AO" opens up the possibility for a non-snow event but its still "to be decided".

Monday, February 6, 2012

You can't spell "Elite" without E-L-I but its time to focus on spelling out the word "Snow"

It was another terrific Pats vs Giants Super Bowl and a thrilling victory for the G-Men. A few bounces here, a less banged up tight end there and things could be different so I solute the Patriots for a great season and a great effort. For a while there, I thought they had the Giants "D" figured out. All that said, Eli needs to get the credit he deserves. Yeah he has some great receivers to throw to, but the whole "Awww Shucks" thing everyone gets on him for serves him well. He has the uncanny ability to shake off all the pressure and make big throw after big throw no matter the gravity of the situation.

So the Giants did their part, it is now mother nature's turn. Let me preface the following by stating that I am going to only remain cautiously optimistic since selling my soul to powdery forecast has done nothing for us. We are finally in the throws of a generally favorable high latitude blocking pattern but we continue to wait for the snow. We had alluded to a weaker disturbance that had the potential to freshen things up for Thursday but this will slide innocently to the south. Temperatures with the help of sunshine, will exceed the freezing mark for a few hours both Thursday and Friday afternoons

That brings us to the weekend and the big southward advance of the Polar Vortex. To a weathergeek like me, anything with the word "vortex" is going to be exciting, so I consider the "PV" to be a fun topic of conversation. In the two days since the last update I had hoped we could better sort the picture out this weekend. We have made a little progress but uncertainty remains. Generally speaking the Euro still shows a softer PV invasion and as a result, a clipper system is able to get some traction with moisture from the Atlantic Ocean and spread snow across interior New England Saturday. The American model shows the PV overwhelming the region resulting in a very cold but generally drier forecast. I am more inclined to side with the Euro on this although not wholeheartedly. This would mean our next chance for accumulating snow is Saturday.

A second impulse Sunday could bring another round of snow showers but it will be remembered more for triggering the southward advance of what is likely to be the coldest weather of the season. Bitterly cold temperatures is typically the end result of any intimate relationship that develops between New England and a Polar Vortex and this should be no exception. Temperatures of 15 or 20 below zero Sunday night or Monday is not out of the question.

The longer range outlook has improved slightly. We should see a significant temperature moderation by the middle of next week but the pattern looks significantly more active. This includes two potential precipitation producers in the period between the 14th and 18th of the month. Although the AO is expected to remain negative the ridge/trough axis across North America will shift west. It will resemble a fairly typical La Nina set up but I am hoping the support of the AO on the favorable side of what could be a succession of storms.

No "kiss of deathing" allowed in the comments section !!! Lets keep it clean ;)

Sunday, February 5, 2012

Snow remains a possbility late in the week

At the very least, I hope we are at the beginning of a long stretch void of any rain. We are expecting above-freezing temperatures Monday but we should keep this short streak alive as temperatures for the remainder of the week return to seasonable levels without rain. It has been an annoying habit on the blog to keep pushing back the next chance for snow. We won't do that this time which is a moral victory of sorts. What looks to be the most pathetic of disturbances will undercut the large western ridge and bring moisture into New England Thursday. This occurs just prior to when the Polar Vortex across Canada makes its southward descent into the United States. The weak weather system Thursday is nothing you can take to the bank but could provide the region with 1-4 inches. The arrival of the Polar Vortex also brings the chance for snow but this too is uncertain. If the PV progresses slow enough it can allow time for its associated clipper system to interact with the Atlantic, strengthen and spread more significant snows to both the Green and White Mountains in the Friday/Saturday time frame. If it makes a rapid descent, it will simply overwhelm the pattern and suppress any storm development. We would thus see only a period of snow showers before it turns bitterly cold for the weekend. Models have been provided a variety of answers to these questions but its nice to see two chances for at least some powder in the 2/9-2/11 time frame.

Beyond next weekend marked an even more uncertain time as indicated in the last update. The American GFS Ensemble indicating cold the European Ensemble back to warm. Both packages however showed the all important very negative AO. As of the current update both continue to show the negative NAO and have added a little more clarity in the form of a compromise. The bitterly cold temperatures that should dominate for the weekend will give way to yet another warm-up in the Monday the 13th to Wednesday the 15th time frame. The warmer temperatures could prove to be a another perilous stretch but it should be temporary as the support of both the AO and NAO should allow for the return of both colder temperatures and snow to return for the President's Day holiday.

That is all for now, enjoy the Super Bowl, it should be a good one.