Think Snow, Tweet Snow !!!

Monday, December 29, 2008

Relief is on the way

I have not been up to watch the serious erosion of snow which apparently has occurred even around Mad River. I can't handle it mentally and usually prefer to lock myself inside and watch football. Some new snow however will make an immediate arrival on Monday night in form of a fast moving moving alberta clipper. The limited moisture with this system will receive some much needed terrain enhancement and I would expect 3-5 inches by later tomorrow with most of this snow falling before first tracks time tomorrow. The second and stronger system is more of a product of the Pacific. It will make its arrival early on New Years eve but its forecasted track in the last 24-48 hours has shifted south and the corridor of heaviest snow is now expected to be over southern New England. The likely scenario at this point is a light accumulation New Years eve followed by a turn to much colder temps which marks a more permanent shift in the pattern discussed in the previous post.

Pattern aligning itself in a very "right" way
One has to be seriously encouraged with the outlook for the first half of January. The NAO shift is the first triggering mechanism but this will be combined later in the month with what now appears to be a complete elimination of the trough across the west. This is a new development as of today since it was only in the last post that I had still expressed concern about the on goings in the Pacific Northwest and its ramifications farther east. Now it appears as if the NAO shift will be combined with the building of a ridge across the west and this severely weakens the threat for rain for at least the first 15 days of January. If we shut down the Pacific entirely, including the all important moisture supply of the jet stream's southern branch than it could be more of a dry cold but this is jumping a bit ahead of ourselves. The first 10 days of January will feature at least 2 significant storms and I am encouraged that we will recover a healthy percentage of what was recently lost.

Two storms to watch in the first 7 days of '09
The storm this weekend continues to have promise and potential. We will get some snow out of this but uncertainty looms regarding amounts. The storm is another product of the Pacific and there have been generally consistent indications that some additional Atlantic Ocean moisture could seriously boost this storm into a big snowmaker for interior New England. This said, the storm is a quick mover, and the consequences of the storms interaction with the Atlantic Ocean could be felt farther east as opposed to MRG. The second storm arrives in the time frame of January 6th or January 7th. Models at face value suggest mixed precipitation is possible with this but I am counting on the historically reliable NAO to have our backs on this one and discourage this storm from tracking in a unfavorable way.

Saturday, December 27, 2008

NAO turning sharply negative - more favorable pattern will be the result !!!

In the meantime though we are watching the final chickens as they return home to roost in the form of a stretch of mild weather. I am actually feeling a bit fortunate today as it appears rainfall amounts will be much less than feared a few days ago. This mild weather was foreseeable more than a week ago and there was a time when it appeared that some heavy rainfall could accompany this balmy binge. Instead it appears as if rainfall will be intermittent and light and for this I am thankful. No doubt we will lose some snow as temperatures soar to near 50 Sunday and new snow will be slow to arrive in the wake of all this warmth but come in will and ultimately it will come in significant quantities.

Transition back to winter is gradual but two clipper promise results by New Years Eve
The return to the seasonable chill that typically grips the Green Mountains this time of the year will also be somewhat slow to return. Above average temperatures will continue to grip the mountain Monday and it will be mainly dry but by Tuesday winter makes a full return. The catalyst is a clipper system which is a bit short on moisture but with an adequate upper air dynamic punch is likely to produce a few inches of powder prior to Tuesday's opening ceremony. Tuesday morning will be the first of two quick hitting clipper systems and the second on New Years Eve appears more organized and more capable of producing significant snowfall. Snowfall from the second clipper should begin in earnest in the pre-dawn hours Wednesday and continue well into the ski day Wednesday evening. Several inches of snow could be the result so long as this storms track doesn't drift too far to the south (some recent model guidance has been drifting south with the storm track and we will continue to watch it). Overall the period between Monday night and New Years eve could very well consist of snowfall at varying intensities through the entire period but accumulating snow is likely to be limited to the early hours of Tuesday and the early hours of Wednesday. At least one of these days will turn out to be the honest-to-god powder day that we are both hoping for and deserve.

Negative NAO and its results
All of the above is a result of a pattern transformation, largely the result of changes downstream in the jet stream. On the SCWB we refer to the NAO index as a measurement of the amount of jet stream blocking is occurring across the northern Atlantic Ocean stretching from the Davis Straits east across southern Greenland. The most important result of a downstream block in the jet stream is that it becomes increasingly difficult for storms tracking across the U.S. to take a northern track through the Great Lakes and into the St Lawrence Valley. The block, in essence, forces storms that are tempted by such a fate to often reform along the east coast. This in turn keeps mild weather and thaws very well contained. There are times when strong NAO regimes can drift west and cause an outbreak of mild weather across eastern Canada and interior New England. Such was the case in early February of 2005 although the mild weather was accompanied by dryness and sunshine. In this case the end result will not be mild weather at least through the first 5 days of January.

Major storm for the weekend 3rd and 4th
The possibility was in fact mentioned in the last post of a major storm for the weekend of the 3rd and 4th of the month and this is becoming increasingly likely. More specifically the storm appears to be product of a some very intense Pacific energy which may have the capability of reaching into the Gulf of Mexico or Atlantic Ocean for moisture. This could turn the weekend in question (the first in 2009) into an incredible period at MRG since it arrives on the heels of the two clippers in the days prior to New Years Day. It is somewhat disconcerting to see such intense activity in the Pacific and the long range ensembles do suggest that the strongest area of unsettled weather could be out in the Pacific Northwest for the first 10 days of January. If the downstream block does evolve into a major driving force in the pattern I suspect that we can avoid the outbreaks of mild weather in the first half of January which has plagued us even during a rather snowy December of 2008.

Tuesday, December 23, 2008

Incredible December skiing was had but now we must face the adverse part of an adverse pattern

The wind was ferocious enough yesterday to add quite a bit of density to the powder Monday but it was nonetheless epic and I have some pics to prove it which i hope to post over the next few days. The "dark side of the force" is going to lash out in angry fashion over the next week or so and we will have to deal with the consequences and move on from there. The weather pattern's driving force has been a large ridge that has established itself over the northern Pacific Ocean up and through the Alaska-Russia go-between. This has helped place a serious amount of early season cold in Canada, so much so that when the month finishes out it may very well be one of the coldest months our friendly northern neighbors have seen this decade (collectively). This jet stream feature however has generally promoted snow out in the west and in the week of head we will see this type of trend become greatly amplified.

Two weather events over the next 5 days will bring mixed precip, rain and mild weather
For those looking to squeeze every drop out of this recent stretch of fantastic weather, look to grab some first tracks on Christmas Eve as it appears some snow of the overrunning variety may fall. As Wednesday progresses however the snow will give way to warmer temperatures and perhaps a bit of sleet or freezing rain. Until this happens however it won't be a bad day to ski. Temperatures will hover above the freezing mark Wednesday night and precipitation will fall as rain for a time before cold weather re-establishes itself on Christmas Day. We may see a little snow X-mas day but not enough to make for any serious powder.

My lack of enthusiasm stems mostly from the outlook for the weekend as it appears we will be unable to repel a huge surge of warmth which stems from a rapidly amplifying east coast ridge. A combination of snow, sleet and freezing rain (mostly the latter two) is likely late Friday evening. In the wake of this however will be at least a 24-hour stretch of above freezing temperatures and eventually a period of rain early Sunday. I do have some concern that temperatures could climb well into the 40's which when combined with a bit of rain could prove to be a bit of a low blow.

Improvements will be gradual going into New Years and then beyond but at least one of our important teleconnection indicators will make a shift. The North Atlantic Oscillation index which is one of the three indices to be on the more unfavorable side of zero will move into the more favorable category around New Years Day. From here the pattern will find it difficult to simply continue in its trough west/ridge east mentality and we should see our threat of big surges of warmth and rain diminish. The need for some additional new natural snow will be vital at this time and it seems as if the potential is there for a storm between the 3rd and 6th of the month. Get the pattern right and the rest takes care of itself. It appears we take some steps to do this but not until after new year.

Friday, December 19, 2008

Sunday night dump will be an early X-Mas gift

And the snow which has begun as of Friday afternoon will turn early Saturday very powdery and I would thus recommend to our loyal MRG skiers to avoid too much in the way of holiday cheer, get up early tomorrow, and get to the mountain before the 6 or so inches gets skied off. I know 6 inches seems garden variety enough but the weather which results from this weather pattern will prove erratic so when the powder does come it would be best to appreciate it.

For my part, I am especially appreciative of what is to come Sunday. It will mark a temporary break in the trough west/ridge east regime and will allow a storm to send moisture our way from two directions. It will be the Altlantic Coast portion of the storm which will ultimately assume the primary role in weather making and snowfall which will begin later Sunday will become heavy Sunday night and ensure the most powdery day of the season on Monday. Upper level dynamics supporting the storm will move over the region early Monday and encourage snow of the more terrain induced variety during the morning. There is some debate on finer details of the storms actual track. Specifically, whether or not this storm tracks east of or west of Boston and this 100 mile uncertainty could make the difference on where the corridor of heaviest snow occurs. An east of Boston track would have the storms heaviest snow in New Hampshire. Either way however snowfall totals will be healthy and will range between 8 and 20 inches by late in the day Monday. Sorry for the big range but I am far more certain of the event itself as opposed to specific snowfall at least as of now.

The fresh supply of cold air which is currently maintaining a very firm grip on northern Vermont will quickly turn stale by Christmas day in spite of some very cold ski days Monday and Tuesday. As a consequence there should be some concern of mixed precipitation for the 3rd part of our 3 punch combo. Remember this is still a rather tricky overall regime and though we have sidestepped a few potentially thorny scenarios, there will be additional challenges ahead. The Christmas day event may be one of them although it is very close. The pattern between X-Mas and New Years is also tricky and may at some point include a 1-day mild stretch of weather and a rain/ice event. Flatten the eastern ridge a bit more than what is currently being indicated and the result could be drastically different as this weekend is turning out to be.

Wednesday, December 17, 2008

A big 1-2 and possibly 3 punch combo promises powder and lots of it in the week before Christmas !!

Hard to imagine a better Wednesday evening blog entry. Two strong weather systems lead the headline and both are going to provide some powdery goodness over the next 5 days and a possible third within a day or so of X-mas. And for those waiting and worrying about the skiing for Christmas and beyond, the sum of the snow from these storms will at the very least sure up the base and ensure that a healthy percentage of the mountain will be skiable.

The Players
Arctic air which continues to cover the greater majority of Canada is proving to be a potent force and its influence will overwhelm the more unfavorable teleconnections driving the global long wave pattern. With that said we are going to get some support from the development of a very important long wave feature over the next few days. This feature is often described in meteorological classrooms as a "jet max" or an area of "confluence" and it describes a zone where the jet stream is flowing west to east at a very intense speed. When such a jet max sets up near Newfoundland, as this one will, it can produce a very snowy result in the upwind region including New England. The effect of the "jet max" allows very cold, very dry air in eastern Canada to drop southward into the northeast. As the atmosphere saturates with the approach of a weather system, the very dry, very cold air keeps the effective wet bulb temperature very low and expands the area of snowfall over New England. This particular "jet max" will ultimately combine with a manifesting split flow situation in the Rockies to produce one of the snowiest December weeks since 2002.

Storm #1
The first storm will track quickly out of the southern Rockies and into the Midwest bringing precipitation to Ohio mostly in the form of rain. As this strengthening weather system encounters some of the aforementioned cold produced by the aforementioned "jet max" an area of snow will expand across the New York city area and in southern New England. North-central Vermont will be on the northern edge of this expanding area of snow which will begin in the early afternoon Friday and persist at a mostly light intensity into the night. By first tracks time on Saturday, we should have 3-6 inches of powder to ski in. Temperatures Saturday and throughout the weekend will be considerably colder verses some of the expectations earlier this week. High temperatures Saturday will struggle into the low teens, drop below zero Saturday night and then rise into the teens again Sunday. Winds will be out of the north most of the weekend but should not be very intense.

Storm #2
The second system will be stronger and a bit more dynamic. Its track will also be more conducive for a major snowfall for Mad River Glen and surrounding Vermont. Details are certain to change but the storm will follow a familiar story line of strong weather system in the Midwest transferring its energy to the Mid-Atlantic coast and depositing healthy amounts of moisture into New England. Along the coast, early snow will be followed by a transition to rain. Across the interior it will be snow which could turn heavy and lead to a widespread area of 1-2 foot storm totals. Snow will arrive later Sunday and continue into the night and will thus set up Monday as the best powder day of the year so far.

And could it be ?? A third ??
The possible third system will have impact within a day or so of Christmas Day. It will follow a period of very cold weather across interior New England in the wake of Monday's powder-fest. It will however be the third in this series of relatively moist systems to get shot out of the very unsettled pattern in the southern Rockies. It has the very wonderful look of 1993-1994 when the teleconnections were generally unfavorable, the storm track appeared precarious and yet the combination of a strong supply of cold combined with the split flow in the west yielded an epic season of powder. We can only hope that the results will continue to be as good as what this upcoming week appears to be. Enjoy it, I know I will !

Sunday, December 14, 2008

An improved outlook

Some big improvements in the forecast to detail. We still have nuisances that are resulting from the overall pattern and some of those nuisances are still move of a headache. As I mentioned though in previous posts, there has been a very impressive area of cold that has developed over Canada and this is proving to be a major force and a positive one as far as us Vermont skiers are concerned. Below is an abbreviated depiction of North American temps and seeing such a widespread area of -30 degree readings across the western provinces of Canada marks a very impressive start to the winter season.

http://twister.sbs.ohio-state.edu/imageg.php?dispimg=surface/ustemp&imgname=Current+Temperatures+(F)

So the surge of warmth remains on schedule for tomorrow obviously and the mountain should see temperatures rise into the 40's. This warm-up could have been worse in terms of duration and intensity and what also could have been worse is the rainfall later Monday which now, according to our trusty computer guidance, is only expected to total around a quarter of an inch. Tuesday will be dry but we are back in the chill and awaiting our next shot at natural snow.

All three teleconnection indices are either neutral or unfavorable for us and the pattern overall places all the cold and most of the snow in the central or western sections of the United States. Even coastal sections of the Pacific Northwest from Portland, Oregon to Vancouver are seeing significant snowfall as of Sunday morning. That all being said, arctic air covers most of Canada and the eastern ridge now appears as if it will get beat back and flattened as this week progresses. Much of the Mid-Atlantic and Southeast will remain quite mild but latitude will give Vermont an edge and we hope that in the end MRG can be on the winning side of an all out war between the warmth to the southeast and the very cold aforementioned arctic air in Canada.

Active pattern taking shape with 3 wintry events possible in a 6-day period
The specifics include many fine details in what should be an active pattern. The first chance for snow comes Wednesday, a simple case of overrunning where warmth from our southeast sub-tropical ridge is trying to erode the existing New England cold. The result is an area of snow that should persist through much of the day before ending as some sleet or freezing drizzle later in the day. 3-5 inches is a very realistic expectation for this event with an inch or so possible by first tracks time. Next weekend gets even more interesting with two systems on the dinner table. The pattern is such that small changes in the overall long-wave pattern structure will yield profound changes in the track and intensity of both these storms. At this time, the first system on Friday, looks to be another overrrunning event with a surge of warmth from the southeast will induce a zone of snowfall somewhere between interior New England and Quebec. There are still indications that too much mid-level warmth could crush our chances of significant snowfall early in the weekend and cause more of an ice event but I am much more optimistic than I was a few days ago. The second event is also iffy also but could be occurring at a time when the overall ridge/trough configuration across the U.S. is temporarily repositioned in a more favorable way for us as we approach the winter solstice. The upside with the second system is quite high were it to occur since it is a question of snow or nothing as opposed to snow or ice.

And then we move to the Christmas holiday and will still unfortunately be dealing with the ramifications of a rather unfavorable set of pattern variables. If I would have to guess, I think it is likely we will have to deal with at least one system that will bring precipitation other than snow. With that said, cold weather should remain on the playing field; in fact, we could see the coldest weather of the season around the time of the 22nd or 23rd and I would expect arctic cold in some capacity to exert some influence on the region through the rest of the month. It will help in our effort to bring new natural snow to the mountain. I know some don't like the cold when hitting the slopes but for us it is a necessary ingredient when some outside extraneous forces are working against us. Think snow and lets root for the best !!

Thursday, December 11, 2008

By a razor thin margin...

the precipitation late Thursday night into Friday morning appears to be in the form of snow. This is a system that is now plugged into the Gulf of Mexico's moisture source and will track in what appears to be a favorable direction, ultimately passing just west of the city of Boston before continuing on its travels northeast toward the Canadian maritimes. It will a quick moving system with a very confined corridor of snow. This means many locations will miss out and it much of northern Vermont stands to perform the best in terms of snowfall totals. The storm is also oh so close to being too warm at critical levels but it appears as if our supply of arctic cold from Canada has arrived in adequate strength to keep precipitation falling in the form of snow. Indications are though that our friends in central and southern Vermont will not be nearly as lucky with a changeover to sleet and freezing rain more likely the farther south you go. Snow will end or taper to flurries later in the day Friday but snowfall totals will range between 8-12 inches. Temperatures look just cold enough to support power (middle to high 20's) but any sleet could hurt the quality of the snow.

I don't have any good news regarding the pattern in the longer range. Still looking at a big warm-up early next week, a temporary return to cold for the middle of the week before another push of milder air around December 19th. Cold continues to expand very impressively in Canada and if the eastern upper ridge flattens toward Christmas things should get alot more interesting. Enjoy the snow !!

Tuesday, December 9, 2008

Horizon is now littered with trouble

As there now is a building consensus for a well defined western trough and an equally well-defined eastern ridge. This folks is a problem since the Great Lakes are unfrozen and when combined with an ill-favored pattern can make our access cold weather very limited. So a few days ago it looked like we would be dealing with one or two rogue intruders and it now looks like we will be playing defense against a well-coordinated battalion. A strong western upper level trough should be expected from time to time this winter given the negative state of the PDO. Furthermore, our friends out west have been hurting so far this winter as the season has started out both warm and very snowless. Check out the lack of snow across the interior west, a rare sight to have such a widespread area of the mountain-west snowless.

http://www.natice.noaa.gov/pub/ims_gif/DATA/cursnow_usa.gif

The rain on Wednesday is likely to end as snow as cold makes a southward push into northern Vermont late in the day. Clouds will remain in place as a second area of low pressure organizes itself in the southeast and makes a run at New England late in the day. The american model has been generally consistent that precipitation in northern and most of central Vermont falls in the form of snow Thursday night into early Friday and forecasts from the National Weather Service are suggesting as much. The American model at face value suggests that snowfall will be in the 6-10 inch range prior to Friday but the American model is not the only apple on the tree. Alternative model guidance from Europe is suggesting a much warmer system where precipitation is mostly falling in a form other than snow. The European model is the preferred guidance in this time frame so one has to take it seriously and at least assume a compromise and a hybrid system including a mix of snow and sleet for Friday December 12th with total accumulations of only a few inches. There at least remains the potential for decent storm going into what could be opening day so we will wait and watch and hope for some good news.

Flurries Friday and colder weather will be followed by dry and cold weather Saturday. Daytime temps will be in the teens and 20's while low temperatures Friday night will be in the single numbers. Sunday should see a return of milder weather with temps approaching the 30 degree mark. The chances for a powder day over the weekend appear slim however as the atmosphere will quickly stabilize in the wake of our Thursday night weather system.

The week beginning the 14th and ending the 20th is starting to look a bit ugly. The push of very mild air for early next week appears ferocious now and will cover much of the St Lawrence Valley along with all of interior New England by later Monday. At this point our best hope is to limit any rainfall that may arrive in the middle of the week with the incoming cold front. Cold weather arrives toward the middle of the week but its arrival may very well be followed by a quick departure as another surge of mild air threatens to bring more precipitation of a mixed or rainy variety by the 19th and 20th. It appears to be a potentially very lousy weather pattern going into Christmas and we will have to hope that the eastern ridge can get flattened just enough to lower the storm track a few hundred miles. It looks much more adverse today yes, but we did have a few such patterns last year (a negative PDO year) to contend with. For the most part we contended successfully and I can recall specifically how bad the week following the Super Bowl appeared and it turned abruptly and dramatically and we made out very well. Furthermore we do have a substantial amount of very cold weather in Canada and a slight shift here or an undulation there could allow the mountain to put our latitude to good use.

Sunday, December 7, 2008

Arctic air shifts west...

and in a word this is discouraging. We have been in a generally favorable pattern for the better part of 3-4 weeks and many of the low lying areas of Vermont remain snowless. As we head toward opening day, the immediate horizon has the coldest weather so far this season arriving Sunday night into Monday but it precedes a rapid warm-up and what will likely be several hours of rain on Wednesday as a large upper level ridge is allowed to retrograde from the Atlantic Ocean to Atlantic Coast. This was one of my concerns expressed in the last post but even I underestimated the precarious nature of the pattern and the speed at which the cold could be eroded.

There is a silver lining I just wish it was a bit brighter. The mid-week storm system this week is a moist one. As the push of mild weather commences, the region will pick up a few inches of snow Monday night into Tuesday. After what looks to be an unavoidable round of rain on Wednesday and temperatures in the 40's, a fresh infusion of cold air will arrive in front of what looks to be a second wave of low pressure. This could produce several more inches of snow during the day Thursday. If all goes well, the several inches of powder would be the last precipitation to occur before Friday. We just hope that any snow more than makes up for the rain and mild temperatures which is set to impact all elevations on Wednesday.

The westward shift in the arctic air results from a global shift in some very important upper level features. The biggest of which is the movement of a ridge which currently covers western North America but is slated to move rather briskly westward over Alaska and ultimately situate itself over extreme northeastern Russia by the middle of this month. arctic air, and plenty of it will therefore focus its attention on areas mostly west of the Mississippi River. Vermont will have to use every bit of its 44 N latitude and hope for the best. The ensembles have disagreed on the specific impact a strong western trough might have on Vermont. The american ensembles do indicate that an eastern ridge could be weaker and flatter and allow cold weather to maintain a loose grip on interior New England. Along with this would be continuous rounds of winter weather. A stronger eastern ridge however would open the door for an event like the one mid-week to repeat itself.

As early as December 14th there are signs of another mild push and another snow to non-snow event. And whatever happens between the 14th and 16th of the month will have a lot to say about what kind of skiing we will be dealing with going into the Christmas holiday. There is plenty on the table to analyze so lets give it a few days and see how things look then.

Tuesday, December 2, 2008

Mild through Thursday but both cold and snow to follow

Mad River seems to be targeting December 13th as the grand opening. This is still several days away and I don't want to suffer from blogger burn-out early in the season so this update will be kept short. We are dealing with a temporary intrusion of mostly Pacific air in the wake of the Sunday/Monday weather event. Arctic air will make a return by early Friday and with it will come lake effect snow showers of a diminished and occasional variety. There is a clipper system Sunday that is already drawing attention. It appears likely that its interaction with the Atlantic Coast will lead to explosive intensification and at least some accumulation of snow is likely both across interior and coastal New England. Behind that system comes the coldest weather so far this season and likely the first sub-zero temperatures on the mountain by Tuesday morning of December 9th.

Guidance this morning still suggests that much of the cold across the Northern Hemisphere will maintain its focus on North America. The center of this focus remains a question however as there are indications of a westward shift in the mean trough. The result could be an all out street fight between the sub-tropical Atlantic Ocean ridge and arctic air to the west. Active weather would be one of the results including snowfall but there is the risk of precipitation of a non-snow variety. This is more or less how the crystal ball appears beginning around the weekend of the 13th or 14th. Until then however the pattern apppears favorable and there is at least one more clipper system during the middle of next week which appears poised to deliver some additional new snow for opening day.