Think Snow, Tweet Snow !!!

Thursday, December 31, 2015

January 2016 to bring snow and hopefully a lot of it

Happy 2016 ! With the new year comes a snowier pattern and it will come right away. Much of New Years Day and into the 2nd will feature snow flurries and the occasional heavier snow shower. The mountain should receive a fluffy few inches from all this, but a rather dynamic upper level impulse will bring the polar jet into play. Snow showers will become heavier and squallier on Sunday bringing 3-6 additional inches to the mountain before drier and colder air settles into the region Sunday night.

The quick burst of arctic chill has looked more impressive the last few days and will send readings toward the single numbers Monday morning and below zero by early morning Tuesday. If I am not mistaken, it would be the first sub-zero temps of the season. Temperatures will moderate over the  course of the rest of the week but only modestly and no significant thaw is expected. It is expected to stay dry through Friday although the sub-tropical jet will not go dormant.

The last few days has been a rocky period for some of the medium range computer models. Cold weather mongers and snow lovers alike (such as myself) received a scare as a cycle of model runs weakened the upcoming cold pattern substantially. The trend was short lived however as models have recreated the consensus from a few days ago by establishing a solid negative AO / positive PNA combination beginning around January 9th and continuing through mid month. There has been an interesting story regarding the storm in Iceland that became so wound up, warm air was sucked deep into the Arctic region sending temperatures near the north pole toward the freezing mark. This is 50 degrees above average which is an incredible event so far as anomalous weather is concerned. The other interesting caveat was that the last time we saw a storm such as this was late December of 1986, also an El Nino year. Yes, Penn State football and NY Giants football both proceeded to win championships in the month that followed (this will assuredly not be duplicated) but the month was a fascinatingly stormy one, with a succession of winter storms that impacted the eastern seaboard. Warmth near the poles is certainly something that needs to happen to start moving the AO in a negative direction and such a storm has certainly resulted in that. Time will tell if this January turns into a similarly stormy one,  but the pattern suggests it's possible. 

As for storminess in 2016, it appears as if it may begin around the time of January 9th. If the ridge west/trough east pattern becomes too pronounced, some of the storminess could be suppressed. With the present strength of the El Nino, I doubt the pattern will become "arctic" but rather "stormy" including a few chances for big snow starting around the 9th but also continuing well beyond.  We will try to provide some better detail on this in the coming days.

Tuesday, December 29, 2015

Still moving slowly in the right direction as we head toward 2016

Winter !!! Unfashionably late again but it has made an appearance as the entire state of Vermont has finally been whitened by a garden variety winter storm. A bit of fluff this coming New Years weekend should enhance some of the new found positive vibes. This update contains mostly good news but a little bad also the pattern is gradually moving toward a very optimal one with "gradual" being the key word.

The snow/sleet/ice foundation on the mountain will get a little wet at low elevations as temperatures sneak above the freezing mark on Wednesday and Thursday. The midweek weather system that had threatened to spread more wet weather into the region Wednesday night and Thursday will not completely come together. What we should see from that discombobulated storm is some elevation sensitive snow that might accumulate a few inches near the summits by early Thursday. Temperatures will drop to sub freezing levels New Years Day and Saturday with more flurries and snow showers. Best chance for some additional accumulating snow comes Saturday night into Sunday as an impulse drops straight out of Quebec. Snow squalls are likely in this time frame leading to a few inches of accumulation especially on the upper parts of the mountain. The impulse will  also bring a brief shot of arctic chill to the region sending temperatures down to the single numbers Sunday night and Monday morning.

The little bit of bad news relates to the weather next week. Although from a big picture standpoint, we are evolving toward a colder and snowier pattern, we aren't there yet and don't as of yet, have the support of all the key teleconnection indices. Following our little burst of chill Sunday night into Monday, we will see more mild weather during the middle of the week. Perhaps not a major thaw but a few days where temperatures sneak back above the freezing mark. The mild weather will be brief but hopefully it doesn't culminate with any rainfall later next week. Unfortunately it's a possibility though models have yet to come to any real agreement on it.

Much better agreement exists regarding what follows beginning around the 8th or 9th of January. A pattern driven by several key teleconnection indices that will produce much colder and snowier weather for a large portion of eastern North America. The Arctic Oscillation will finally make the critical negative turn and will thus allow significant amounts of arctic air to move southward. The southern branch of the jet stream should also continue to undercut the large ridge in western North America, keeping the threat for big storms alive; in fact, there have been hints 1 or 2 during the last few cycles of model runs.                                                                                                                                                                                                                                                               

Saturday, December 26, 2015

Good foundation laying snow/sleet/ice event Tuesday then winter starts for real around New Years Day !

We've actually gotten through the worst of the warmth though it remains quite mild relative to average. The first in a series of three precipitation producing systems arrive Sunday morning and will bring rain and some areas of freezing rain to Vermont. This should all begin during the pre-dawn hours of the day. For the first time in what feels like forever, the snow/rain line with this system is actually within driving distance, setting itself not far from Montreal Sunday.

A refreshing looking side shot of arctic chill will then dry the region out Sunday night and send temperatures back toward 20 degrees by Monday morning and keeping readings in the 20's during the day. The high pressure center responsible for the cold will try and anchor itself in the Canadian Maritimes as a stronger system advances toward the region straight out of Texas. There is lots of moisture with this storm though it's a fairy garden variety event. The track is not ideal with the primary low passing through the central Great Lakes while a new coastal low tries to reinvigorate the storm off the New England coast. It's all adds up to a rather familiar New England winter storm story but we will take it. Snow should begin across the region sometime after midnight Tuesday and a few hours of moderate snow during the early morning should allow a few inches to cover the northern half of Vermont. Across the high country, we should see snow change to sleet and freezing rain during the midday hours and continue through the rest of the day.  We saw a few models advertise an all snow event on Christmas Eve and Christmas Day but the consensus of data has converged back toward this snow/sleet/ice scenario. A good foundation laying event but nothing epic.

A few relatively mild days will follow in the wake of Tuesday's system. Clouds should keep temperatures on the mountain in the 30's but below 3,000 feet should be mostly above freezing both Wednesday and Thursday. Lingering upper level energy in the midwest is going to try and take more subtropical moisture and churn up another storm. There has yet to be any real consensus regarding any of this except the lack of cold air. Whatever falls Thursday, rain, drizzle or just a shower or two will be the liquid form. I don't think whatever falls will be enough to eradicate the early week foundation.

Winter gradually establishes itself across the region New Years Day and this should begin an extended period of sub freezing temperatures. It's also a period where any precipitation that falls should be in the form of snow. Though there are no indications of big east coast storms, there are clipper systems that dot the weather map on all of the extended models. Furthermore, I am not a believer that the southern branch goes completely dormant. This is a giant El Nino year and both Gulf of Mexico and Atlantic Ocean moisture should be able to stay involved in the weather pattern somehow though the models aren't showing that as of the time of this update.

I can't advertise the coldest of weather patterns in January but enough to make it wintry. The American Ensemble members are suggesting a more aggressive turn by the AO index into negative territory while the European and Canadian Ensembles show a more modest move to just slightly negative. The MJO which continues to be worth watching this winter, will continue to move toward phases that teleconnect to much colder weather in eastern North America, ultimately landing right in the middle of phase 7 in early January. If nothing else, this should control the evil empire and keep the Pacific away from its menacing December self. Meanwhile, the dominant player should be a large ridge in western North America which will keep the PNA positive and keep temperatures mostly south of the freezing mark.

Wednesday, December 23, 2015

Some snow with next week's storm ? Maybe

More good news is visible through the rain drops and very warm air. The active weather pattern next week is still not associated with the best of weather patterns but we will have some arctic cold that will mix itself into the equation. Temperatures will gradually cool Christmas Day and into the 26th following an insanely warm Christmas Eve.  Two weather systems will then impact the region with the first bringing its precipitation Saturday evening and the second stronger system Tuesday evening.

Both systems were discussed in the last update. The first looks a touch warmer and appears to primarily be a rain event though a few spots could see some freezing rain. A respectable looking shot of arctic cold comes in the side door Sunday evening and make for a wintry but dry Monday. The high pressure center responsible for the chill appears stronger every day and will thus be able to attain a firmer grip on interior New England before the arrival of this aforementioned second storm Tuesday the 29th. A couple of days ago this looked like a sleet/ice event but each cycle of model runs seem to offer a better and better chance for snow. As of right now, the event appears to be sleet/snow event which would lay a nice foundation to build on going into 2016. The situation has and will continue to evolve over the next few days but the best chance for an all snow event is across extreme northern Vermont and into Quebec which of course includes the likes of Jay Peak.

A day or two of above normal temperatures in the wake of this 2nd system will precede the arrival of a new and improved weather pattern to begin the new year. I want to highlight the fact that although we expect some continued improvements, the pattern does not appear overwhelmingly cold. The AO will level out but I don't expect the index to get seriously negative and the absence of blocking in the jet stream in the polar regions will make the transport of seriously cold arctic chill difficult. The pattern will be anchored by a weakened Pacific Jet and a western North America ridge. Jet energy will undercut this ridge and I am hoping this will help brew up 1 or 2 big east coast events during the first 10 days of January.

Monday, December 21, 2015

Our long awaited pattern change is finally in sight !!

Happy solstice (officially Tuesday Dec 22 this year). With the darkest day of the year comes brighter news. Though some incredibly persistent warmth will continue to cover eastern North America through the Christmas holiday,  it should finally end around the New Year and winter will finally make an appearance. I don't expect a sustained period of extreme cold but with the AO leveling out and even going slightly negative combined with the disintegration of the evil empire in the Pacific, the snow should finally start to accumulate and we will move closer to an opening at MRG. There are even more encouraging signs within this new pattern that should serve the region well and that will get discussed a bit at the end.

In the meantime we still have to contend with the last 10 or so days of this near tropical weather pattern. After a bit of light rain Wednesday night, Vermont will enjoy what might very well the warmest Christmas Eve anyone of us will remember. Temps in the 60's, no snow on the ground and maybe even a thunderstorm to go along with the egg nog late in the evening (though that's probably a slim chance). Absolutely insane ! No point worrying about damage control with nothing to damage. With no base on the mountain, might as well enjoy the warmth rather than get insulted by it.

The Christmas to New Years stretch will not be quite as mild but nonetheless mostly unproductive. It will be an active stretch of weather with the first storm bringing rain and ice to the region Saturday night. As mentioned in the prior post, arctic air will make a rare December 2015 appearance as it presses southward against the large enveloping east ridge. Vermont will get a taste of this chill later Sunday into Monday the 28th as temperatures fall into the teens and remain mostly below freezing Monday. The cold will never attain a firm grip on the region and will be mostly scoured out of the region by the next, even stronger weather system on Tuesday the 29th. Though we might see some additional sleet or ice, we are unlikely to see any snow out of this system. 2015 will finish the year on the mild side with readings generally above freezing during the day and only a few degrees below freezing during the night.

With the new year comes a new pattern finally. Though not an overwhelmingly cold pattern,  the playing field will be leveled if not tilted somewhat in our favor. Our biggest asset will be the development of a large ridge in the jet stream across western North America which will boost the PNA index well into positive territory. This will be the mechanism which should essentially keep temperatures below the freezing mark for an extended period of time after the new year. Without the overwhelming presence of the polar jet or a polar vortex, activity in the southern branch of the jet stream should also persist. This should keep the door very open for a big east coast storm and I expect at least one between the first and 10th of January 2016.

Enjoy the mild weather and don't let it damage your spirit. Better times are finally in sight.

Saturday, December 19, 2015

More signs that we will move from bad to less bad

More evidence both yesterday and today that this abomination might be closer to an end. There is no indication of an abrupt turn to sustained below normal temperatures, no suggestion of a big snow and certainly no Christmas miracle to save the holiday. It certainly doesn't look quite as bad way out there on the horizon. Increasing amounts of arctic air will cover North America over the next week and although it will have a difficult time reaching Vermont, some eventually should, even before the new year. After the New Year, there are signs of some fundamental changes in the Pacific with a partial breakdown of the evil empire. We will still be contending with a mostly positive AO but the battlefield will be a bit more level.

There are a few changes in the short term but nothing of real consequence for powderhounds. Any weekend snow will again be faced with several intrusions of mild air over the next week. Some light rain accompanies the initial push of mild air Monday. This is followed by a much stronger push of warmer air Christmas eve which is also accompanied by light rain With the exception of some areas around Lake Superior, no one east of the Mississippi River get a white Christmas; instead, most of New England will see temperatures in the 50's and even 60's (in southern New England) on the 24th and only slight cooler on the 25th.

After Christmas the playing field looks like this. A sharp boundary of temperatures marked by a stationary front will establish itself from somwhere from Texas to the northeast. A ton of mild air will grip much of the eastern seaboard but arctic air will begin pressing against the large upper air east coast ridge. Some of it will reach New England by the 27th or 28th. There is an organized storm system that will eventually materialize by the 28th and again will try and push mild air northward. With the east coast ridge weakened and with some minimal cold air available, the situation looks at least somewhat more interesting if not a little promising. It's basically one model out of every 5 indicating any real snow but that's certainly an improvement.

Beyond the New Year it appears as if the large mid-latitude dome of death we have been calling the evil empire will get beaten down. No evidence yet of any blocking anywhere near the arctic so I would describe the situation as a soft turn toward what should be a less adverse situation. The biggest asset might be the partial development of a positive PNA that includes a ridge in western North America. 

Wednesday, December 16, 2015

I have no new found love for this years holiday weather but beyond that maybe

I don't have any new found optimism for the holiday period I am sorry to say. I can however begin to hang my hat on the Madden-Julian Oscillation or MJO so lets do that together before the warm weather further irritates our holiday cheer. Without getting into intricate details, the MJO phases define various cyclical periods of convective activity over the Indian Ocean and lower latitudes of the Pacific Ocean. To put it as plainly as possible, such convective activity has the capability of re-dealing the cards in the Pacific Ocean. Over the last 6 weeks, we have been stuck in Phase 3 and 4 which is generally a warm phase for eastern North America since it correlates quite directly to a strong Pacific Evil Empire. Over the next two weeks however we will shift to phase 5 and subsequently into phase 6. Phase 5 is still very warm and Phase 6 is less warm. Further extrapolation would take us toward phase 7 after the New Year however. If the aforementioned convective activity reaches this phase, the deadly ridge in the Pacific would get broken and the jet stream loosened. Though there are no glaring signs of this yet, I am tentatively going to expect a pattern change between January 5th-10th and this is one reason why.

In the short term we have an another all rain event arriving Thursday evening. The wet weather clears by Friday and temperatures begin a slow and very temporary descent toward normal (though they probably fail to get there). On Saturday, it will actually feel like December, somewhat anyway. Models are actually predicting a few decent streamers off the lakes (geek speak for snow squalls) and if the mountain is positioned under one of them for a bit, we could see several inches of snow. Perfectly reasonable to expect a few inches across the high country but it won't be the kind of snow with any staying power.

Any snow is out by later Sunday and the mild air is back by later Monday. There are a few weaker weather systems that will pass during the early part of the week. The first Monday could provide some mixed precipitation though not a lot later Monday. The 2nd during the middle of the week is probably mostly rain. Another big push of warmth follows for the Christmas holiday bringing another round of much above normal temperatures. Ensemble data is pretty clearly indicating that the mild air will continue to dominate at varying intensities until at least the New Year. There have been a few teases from operational model runs advertising a bit more excitement but this is only a little short of praying for a miracle.

Sunday, December 13, 2015

December 2015 poised to completely bite the dust

Believe me I want to bring better news but I don't have any, not yet. We will get a burst of winter chill this upcoming weekend but it mostly comes in the form of sub-freezing temperatures. What's worse is that the chilly near average temperatures will be quickly displaced in the days prior to Christmas and this pretty much cements the month certainly as one of the worst December's I can remember and quite possibly one of the worst months of skiing in the east I can remember. December 2006 also featured an El Nino, albeit weaker, and that month along with the first half of January was also extremely mild. Given the behavior of the Jet Stream in the Pacific and wrong type of preferential treatment being provided by the Arctic Oscillation, I would be very happy if we could simply mimic the results that winter which featured an epic 6-week stretch of weather.

A healthy dose of warm rain Monday evening and Monday night will precede a few days where the weather is simply "not as mild".  I mean, it's a pretty ugly scene in Vermont when temperatures in any of the winter months fail to drop under the freezing mark in the wake of a cold front. Wednesday and Thursday will see temperatures near but not much under the freezing mark during the early morning before readings rise to near 40 during the afternoons. Another storm system then approaches Thursday evening but with essentially zero cold air support. The storm will actually transition much of its energy to the coast late Thursday which is typically a very encouraging development. In this case, temperatures may remain in the 30's but precipitation will be mostly rain with a few areas of freezing rain.

Flurries and snow showers finally arrive with the arrival of much colder weather later Friday. Conditions look pretty good for at least a few inches of Champlain/Terrain induced snow particularly Saturday and Saturday night.  A few flurries may linger into Sunday before we say adieus to the cold early next week.

The jet stream in the Pacific is simply behaving horrendously for us. The coupling of the troughing in the Bering Sea over the ridge in the central Pacific is just catastrophic. Some have argued to me that this El Nino does not have a causal relationship with this feature but this is incorrect in my opinion. The trough in the Bering Sea is unfortunate but the ridging in the central Pacific can certainly be attributed the massive area of warm water near the equator. My concern relates to this aforementioned AO and it's inability to attain any sustainable negative index. I have noticed this during many of the winters I have followed the weather. The AO has a preferential sign during certain seasons. The 2009-2010 much weaker El Nino featured the biggest negative AO ever recorded. This year we are setting up to be largely the opposite. Someone more academic than me is going to have to chime in as to why this tends to occur, or perhaps it's all in my head.

Anyway, the weather pattern out around Christmas is showing glaring signs of another massive thaw. The ensembles over the past 24-48 hours have really consolidated around this scenario and I don't want to sugarcoat it. The rest of the month looks pretty shot. 

Thursday, December 10, 2015

Some winter chill and even a chance for some snow during the weekend of the 19th and 20th

Pretty much as bad as it gets over the course of the next week but having no snow to melt means no much to lose. Both big massive western systems fail to do us any favors. The first comes behind the massive push of warmth this weekend. Doesn't look like we get out of the 40's and 50's thanks to clouds, fog and probably some drizzle Sunday and Monday. Rain from the first system arrives Monday evening and clears out Tuesday with little to no cold push. 

We had held out a bit of hope on the 2nd system but that too is gonzo. Storm will ultimately follow a similar path as it's predecessor. Temperatures will be a little colder and the rainfall is not likely to be as heavy but frozen precipitation does not appear to be part of any equation through Thursday of next week. 

There is some good news in the form of what appears to be a 3 day interval of widespread cold weather which will begin late next week and persist through about the winter solstice. During this time frame, some terrain enhanced snowfall is likely. A close examination of the Euro Ensembles offers even more hope by hinting that more southern branch energy spins itself into a significant east coast storm. There was talk on social media from the weather weenie world about this yesterday and the ensemble run provided some support for this so it was worthy of a mention. That said, none of the other medium range model packages provide any agreement of this. The only thing we can say for sure is that some form of winter will be present for a few days between 12/18 and 12/21. 

Without any real support from the AO or EPO, which in spite of the chill down late next week, is not expected to occur. We should not expect the cold weather to sustain itself through the Christmas holiday. There remains pretty good support that the cold will lose it's grip on the east coast by the 22nd or 23rd of the month. Right now, it doesn't appear as if the warmth will resemble the intensity of what we are expecting over the next few days, it's nonetheless discouraging. 

To be perfectly blunt, I still expect some dramatic improvements but nothing material until 2016. 

Monday, December 7, 2015

The gory details of bad to worse this weekend

It isn't a pretty sight for any of the ski areas across the east and it ain't getting better any time soon I am afraid. Over the last few days, models have more or less decided that the trough across the west will consolidate around two massive systems this weekend. Both will pummel the west with snow and deliver many ski areas there, particularly around Lake Tahoe, some of the best skiing in a few years. The last two cold winters at MRG have not been kind to the west lets not forget. This consolidation of the trough in teh west forces the situation from bad to worse across the east. The massive upper ridge which has locked itself in across eastern North America will get another boost allowing for big time and widespread warmth almost everywhere in the northeast. Models have backed off a touch on the magnitude of the warm weather, so maybe it won't quite reach 70 in parts of Vermont. Needless to say we are looking at an extended thaw, though the only thawing is the few inches of crust at the summits.

First chance for precipitation comes Thursday after what has been a rather nice stretch of dry weather. Precipitation on that day will be rain with a few isolated pockets of freezing rain. Friday through Monday are all very warm. How warm depends on the ability of the lower troposphere to mix itself out which will require some healthy southerly winds. Models are still a little unsure regarding how much of this very warm flow will reach central and northern Vermont. If we can achieve some sunshine, temps will be off to the races, reaching as high as 60 even at the base of MRG. If winds remain calm, low clouds, fog and drizzle will keep readings in the 40's and 50's. A moist weather system will track toward Quebec early next week. This is the first of the two big western storms, and this will bring more rain on what will at that point be a very bare ground.

The 2nd of the two big systems in the west will have some colder weather to work with but not much. In addition, the track of this system is not looking favorable. Still, there is some chance for at least some snow along with mixed precipitation and rain during the middle to later part of next week 16th-18th.

The two big critical variables remain extremely problematic right now. No high latitude blocking indicated by the positive AO and the tightened jet in the Pacific indicated by the positive EPO. Some have pointed out to me that the various ensemble forecasts are showing a negative AO in two weeks around the time of the solstice. The jet stream anomalies tell a different story however and are showing no blocking of any kind through nearly the Christmas holiday. I would thus conclude that yes we could get a brief surge of cold for a day or two but the pattern is not supportive of any type of persistent cold through the Christmas Holiday. I am still holding out hope for a juicy southern streamer to deliver a good elevation sensitive interior snow. There is a slight, slight chance for this with the storm later next week and a better chance during the week leading up to Christmas, but this is clearly the best we can do right now.

Friday, December 4, 2015

Mild, mild and more mild but storminess should start to increse late next week

A couple of days into December and I am still wishing I had some better news to deliver. For the upcoming few weeks there are two big fundamental variables which are destroying the first full month of skiing for us. 1) Tightened jet across the Pacific which can be measured somewhat by the positive EPO index 2) Positive AO (Arctic Oscillation) indicating, especially in this case, the complete lack of high latitude blocking in the jet stream. The best we can hope for through about the time of the winter solstice is for a real juicy weather system to deliver some big snow without much help from significant cold, since we are not expecting much for a time.

We have entered into that dry period I was talking about a few days ago. The weekend will be dry and mild including temperatures around 50 Sunday. More clouds on Monday should keep temperatures in the 40's but even that is at least 10 degrees above normal for the high country of Vermont. There is an upper level system early next week worthy of mention. This feature is an offspring of the energy in the Pacific. The feature will pass unnoticed across the Midwest but will help energize a coastal low near the Virginia Tidewater late Monday and this system might impact parts of southern New England Tuesday. A few runs of the Euro and American GFS earlier this week showed this storm achieving some sizable strength and thus delivering some rain and wind for coastal areas. Without any cold air however it was hard for me to get too excited about anything with this storm and it looks now as if the system will have a minimal impact on almost everywhere.

Vermont is expected to stay dry through most of next week but things will begin changing on the precipitation activity front as early as Friday of next week. This first potential system is the first product of some splitting in the stream and this could bring significant precipitation to all of New England in the Friday Dec 11 - Saturday Dec 12 time frame. There is a teeny tiny supply of cold air Thursday but not much to anchor it down and I am inclined to believe the best we can do from this is a period of ice.

Models diverge the week beginning December 14th with our hopes for anything exciting pinned more toward the progressively biased GFS ensembles which I am not inclined to believe right now. The American GFS breaks down much of the ridging in eastern North America by allowing the energized southern branch to undercut the vast area of upper level warmth. This would not be a particularly cold outcome with no arctic air delivery device but it would be stormy and with a little luck, some of this stormy would come in the form of snow. Both of the other medium range ensemble packages consolidate much of the energy in the west and thus show a very well defined trough west/ridge east outcome and potentially some record warmth in the east. I am not completely sold on this idea in spite of some consensus mostly because the undercutting scenario is plausible given the strength of the ENSO.

Sorry for all the crap news but ENSO's such as this years big El Nino are known for some horrendous periods and we might as well get this one out of the way in November/December and hope a long stretch of better times in January and February.

Monday, November 30, 2015

Tough to find any winter in this pattern but I am looking !

We role quite quickly into December but this transition into the winter months has been quite slow from the standpoint of weather. A very mild weather pattern has strengthened its grip on eastern North America and the ski areas, east of the Mississippi River will suffer as a result. The EPO (Eastern Pacific Oscillation) is the big culprit, allowing the "evil empire" into our lives almost in time for the new Star Wars movie. There is a lot of jet energy south of the Bering Sea and we desperately need the atmosphere to relax across that part of the globe for positive changes to emerge in New England. This is a very problematic part of the winter equation this year however since the powerful El Nino is pushing the jet stream north in the south Pacific and contributing to the head ache. All that said, we can still split the flow across the U.S. and possibly generate a little excitement through December 20th. It will be a tough go with above normal temperatures expected to about at least the time of the winter solstice.

In the short term, a large and disorganized weather system will bring it's moisture into the region for the first few days of December. Some areas will see some ice for a few hours Tuesday evening but Wednesday will be generally wet with temps in the upper 30's. We will see some snow from this system eventually however. This occurs Thursday as the upper air component of this storm system passes us. Amazingly, there is little to no arctic air with this storm and snow will be supported by near freezing temps at best at the base and maybe upper 20's at the summit. Not very impressive, but the mountain will likely see a few wet inches, with as much as 5 inches at the summit.

We have a long stretch of generally dry weather that will follow for the first full weekend of December, persisting through most of next week. Temperatures will remain mild relative to average but not incredibly warm. Most of our nights will be well below freezing though many of our days will see readings above freezing and even above 40 in a few instances. Organized precipitation will generally be confined to rain or snow showers but shouldn't amount to much.

The pattern remains supportive of mild temperatures beyond that but we should see an increase in storminess. The first organized system should impact the region between the 12th-14th of the month and another may follow between the 16th and 19th of the month. Both should be products of the powerful jet in the Pacific. Though we have little cold air to work with, the jet stream is expected to split in this time frame with one piece guiding the storms through the southern United States while the rest retreats deep into Canada. The right set of circumstances could allow for a good interior elevation sensitive snow event but that's about the best we can hope for right now. Happy December !

Wednesday, November 25, 2015

Can this season's big El Nino wreck our winter ? Outlook 2015-2016 is here !

Mild weather has assumed control of the weather in New England. The prevailing warmth began in September, messed with our foliage somewhat, and has since continued to dominate the region through most of November. This represents a big change verses the previous autumn and it would be natural to be fearful of a such a trend continuing through the winter. From my perspective, there wasn't much point in tweeting and posting to the blog with little or no encouraging news for powderhounds. Thanksgiving upon us and the time has come to get started so away we go. There's also plenty to talk about. Many know about the intense ENSO event that has enveloped the equatorial Pacific Ocean - El Nino, which has already and will continue to have a loud voice regarding the behavior of the weather this winter. El Nino's of this magnitude should make us a little wary but as I will later show, they are also not to be automatically dismissed as wasteful seasons. We also have a few variables working in our favor which I hope will help the season reach some respectability in spite of a less than favorable short term outlook.

This short term outlook has not gotten better over the past few days. To put it simply, we are not getting any high latitude blocking to help mitigate the impact of what is a furious jet stream in the Pacific Ocean. I can look at the weather map and without even knowing it, tell you that we are contending with a big El Nino. Mild weather will thus be the result, but New England will not be as mild as our com-padres in the central United States. A storm during the first two days of December is likely to be either ice or rain. After that we should remain modestly above normal on the temperature front and there is a chance for an impact from a stronger southern stream system in between December 5-10. We are going to have to remain patient here by the looks of things. There are no indications of a major pattern change and I personally don't think we will see such until at least the time of the Winter Solstice.


Getting back to the seasonal aspect of our outlook we should discuss our current El Nino in detail. Yes, it's a big deal and hopefully not a big problem. We started to see evidence of this El Nino just as we were putting a wrap on last season. Subsequent strengthening over the summer and autumn has brought us to where we are now - an ENSO event that has, in magnitude, blasted through anything else we have seen since the great El Nino of 1997-1998. The critical "3.4" region of the equatorial Pacific which is a vast expanse stretching from 120-170 W (about the width of the U.S. from east coast to west) is now seeing water 3 degrees C above average as of mid-November. Statistically speaking this is putting the event toward the right edge of the bell curve or beyond 2 standard deviations from normal. We have been quantifying ENSO since the middle part of the 20th century and this is how it shakes out comparing each November.



Rank   Year    SST Anom

1)     1997    3.26

2)     2015    ~3.05

3)     1982    2.54

4)     1972    2.03

5)     2006    1.24




El Nino's featuring SST anomalies of more than 2 degrees C in this critical 3.4 region of the Pacific have a relatively clear behavioral distinction in the winter. The south gets extremely wet from Texas to the Gulf States to the Carolinas. The north-central region of the U.S. including the Midwest and Plains is typically mild and quite dry. Most importantly for California is an invigorated jet stream which typically positions itself further south verses other years and drenches the state with rain. This same jet stream also makes it difficult for Arctic air to maintain a grip on large portions of the U.S. east of the Rocky Mountains. New England typically is also enveloped by mild weather and although the region has at times stays dry, statistics suggest that storminess ultimately finds its way to the state and a healthy chunk of that precipitation is snow. The "big 3" ENSO events of '72-'73, '82-'83 and '97-'98 were all mild relative to average and all had some horrendous periods of warm and snowless weather. Somehow though, all three saw decent amounts of snow of either average or above average thanks to a few epic periods. In the case of '72-'73 it was an epic, nearly record breaking start to the season in November and December. This was followed by one of the worst January/February periods ever when the snow depth at Mt Mansfield actually dropped. March and April then proceeded to be very snowy. The winter of '82-'83 looked very much the opposite with warm and dry weather at the start and some snow and cold at the end of January and February to keep things respectable. The winter of 1997-1998 was quite warm but Vermont did quite well relative to many places, avoiding many thaws (one with a historic ice storm) and receiving above normal snowfall.


The "mild but sometimes stormy" behavior is not a statistical accident but a function of the ENSO. Arctic air has a difficult time gripping the region for any real duration but the massive and energized southern branch of the jet is sending some big and very juicy systems up the coast. The Valentines Day storm of 2007 is one such example, a storm that spared the I95 corridor of significant snowfall but dumped 15-45 inches across upstate New York and interior New England. The "Big 3" El Nino winters were all generally pretty snowless winters for the big east coast cities. The big "Megalopitan Storm" of February 1983 brought snowfall totals to respectable levels that season but aside from that, snow along the coast was sparse. 1972-1973 featured only traces of snow for a few east coast locations and 1997-1998 wasn't much better. The moral of this whole story is that although many snow lovers along the coast will be moaning and groaning, snowfall across the interior from the Appalachian Mountains all the way to New England, does occur and during favorable stretches of the winter, falls quite heavily. I expect this season to be very much the same across Vermont this winter in spite of a rough start.

The PDO or Pacific Decadal Oscillation has played such a massive role in each of the last two winters and deserves some detailed analysis once again. The PDO went positive during the winter of 2013-2014 after a long stretch of negative months. It subsequently turned very, very positive in late 2014 and become the strongest "positive PDO" every recorded during the aggregate of winter months through 2015. As of late autumn, it remains a very positive 1.47 which is very respectable though not quite a record. For some detail on the PDO here is some WIKI help - PDO detail. I also probably spent each of the last 10 Seasonal Outlooks describing it so you can check out that as well. It's safe to say that it will remain positive for at least a good part of this upcoming winter and this is fairly typical during an El Nino, particularly one of this magnitude. We have noted each of the last two winters that though the PDO has been a very strong player in some of the strong outbreaks of cold, it has been the specific nature or characteristic of the PDO which has, in my view, been critical. Take a look at the SST anomaly map in the Pacific Ocean in early February of last year.



Note the large area of warmth in the northwest Pacific. This "red blob" was very good to us, promoting big surges in the PNA or frequent large upper air ridges in western North America.  The same map taken during November of this year still depicts the "red horseshoe" which characterizes a positive PDO event but the differences are nonetheless evident.


The "red blob" in the northwest Pacific, although still present, is not the dominant feature. The warmth in the northern half of the Pacific is actually spread out over the eastern Pacific. The biggest feature there of course is the massive area of red near the equator. That is what this year's "El Nino" looks like on this map. No doubt it is not messing around this year !

The PDO should therefore continue to make a more positive contribution to our weather, at some point but I am not expecting it to be the factor it was the past two seasons, in spite of its strength.

For the third consecutive year, we had a big time build up of snow in the autumnal months across the northern hemisphere. Looks like we will need the help but at least we have it. This past October chimed in with 21.4 millions of sqkm of snow across the NH which was the 7th highest of the 48 years recorded. Last years 22.5 number was the third highest over the same period. A rapid expansion of snow and ice in the autumn months helps the arctic air across the northern latitudes pool more efficiently and attain a greater strength. The prevailing weather pattern still needs to support the transport of cold into New England for us to feel the effects of such a variable but eventually I think we will get that support.

During the last several seasons we have spent the last chapter of these prognostications discussing whether or not the weather has been displaying any "tells" to borrow some poker terminology. Particularly in November, the weather pattern will exhibit behaviors that will foreshadow the upcoming personality of the season. During the last two winters, big surges in the PNA brought particularly intense shots anomalous cold into Vermont. Both were statistically eye popping and were indicative of much of the weather that was to follow. During the fall of 2011 several shots of cold weather failed to come in as advertised and this also was a pattern that repeated itself during the ensuing winter. 2009-2010 was another, albeit, weaker El Nino winter but was actually dominated by repeated high latitude blocking events. One large event actually occurred in October and largely foreshadowed other, similar such events that occurred both in December and in February.

This particular piece of the preseaoson outlook is the most disheartening. The pattern just appears to be so overwhelmed by the El Nino this year including dry, warm weather which has dominated the northern plains, wet weather across the south and particularly intense activity across the Pacific. Just in the last week, the jet has become viciously strong in the central Pacific Ocean thanks to the jet energy south of the Aleutian Islands coming over the top of strong El Nino induced ridge in the south Pacific. It appears structurally different than the EPO creatred "Evil Empire" which dominated the horrific winter of 2011-2012 but the effect is the same - limiting the amount of available cold across a broad area of North America.

Once this is all boiled down to an actual forecast it looks like this. Even the big snow cover number we saw in the NH this October/November will not be able to thwart the mild weather. Temperatures this winter will average 2-4 degrees above normal for the season. That said, I expect a stretch during the winter with some respectable cold though this will pale in comparison to the cold last winter. The snowfall result should be better than what we see on the temperature front. Expect some very crappy periods, such as the one staring us in the face for early December. When the pattern does align though, we should 1 or perhaps 2 amazing stretches of weather. I am going to guess that this all happens in the Jan/Feb period right now but it's tough to know for sure. Snowfall should come in around average.