Think Snow, Tweet Snow !!!

Wednesday, February 28, 2007

Lots of fresh powder for Friday morning then a little sleet

The Valentines Day Blizzard was the strongest winter storm to impact the region this season without question but the runner-up may be the upcoming March 2nd to 5th event. This is an entirely different beast but the news with this system is mostly positive since above all, its effects will be felt beginning Friday and persist into Monday or perhaps even Tuesday of next week. This is the second in a succession of huge winter storms for the Upper Midwest, an area which has been snow starved most of this decade. Usually, systems which strike the Midwest hard with snow bring a combination of snow and ice to Vermont and New Hampshire and the forecast challenge becomes predicting all of the precipitation types, amounts and the timing of all precipitation changes.

Storm details - 6-10 inches of powder for first tracks Friday
As the storm continues toward the eastern Great Lakes and brings a push of warmer temperatures with it, a second low pressure area will form near Long Island and re-concentrate the heaviest precipitation over Northern New England. More importantly, this second low will prevent some of the warmer temperatures from invading MRG and changing precipitation to freezing rain and rain. So here are the specifics as best as I can see. Snow will develop at MRG within a few hours of midnight Friday and quickly become moderate to heavy in the pre-dawn hours. Based on some of the latest higher resolution model data, a quick 6-10 inches of powder is likely by the time the single chair begins churning Friday morning at 9 am. This of course means some dynamite runs early in the day. Cross section profiles however show above freezing temperatures overspreading the region during the morning which would quickly change precipitation to sleet which is then indicated to continue through the duration of the ski day. Sleet although less than ideal is not terrible to ski in but can feel like needles driving in to your skin while skiing at higher speeds. Freezing rain may be less painful on your skin but I would hate to see a one inch glaze of ice atop the 3-6 feet of snow currently on the ground at MRG. This deplorable situation will be mostly avoided in northern Vermont since the above freezing layer is above 8,000 feet with well below freezing temperatures remaining in place below this layer. All in all, I think skiers will be happy with Friday's results. The heaviest precipitation is indicated to fall as snow and the icy precipitation is shown to fall as mostly sleet. Total accumulations snow/sleet by Friday evening will range between 8-14 inches. And by the way, precipitation goes back to snow Friday evening and may add a few additional inches to this total by Saturday morning.

Terrain induced snow for the weekend
What I am especially excited about is the set-up in the aftermath of Friday's precipitation. The upper low which is closely associated with the original Midwest winter storm will push slowly toward and through the region during the weekend and early next week. As a result, low level instability will increase and set the stage for a long duration terrain induced snow situation. Winds will be west-southwesterly and it will not be especially cold over the weekend. It may very well turn out to be one of those early spring situations where sunshine and near 35 degree daytime temperatures prevails in the valley locations while snow showers in the mountain locations are occasionally producing heavy snow. The highest snow totals strictly from the terrain induced snow are most likely to fall in the north but the additional snow between Saturday and Monday could very well exceed a foot at MRG and this would include significant amounts of fresh snow at first tracks time both Sunday and Monday.

Rest of next week/Telefest weekend
The terrain induced snow could very well persist through Monday Night into Tuesday since at this time a reinforcing shot of colder weather is expected to make a push into the northeast. Dry and cold weather will temporarily prevail for a time during the middle of the week before another system takes aim at the region, again threatening to bring a signficant push of warmer temperatures with it. We have stiffened our differences on two different occasions and will avoid rain in both instances but in this case (late next week) we are in hot water. The upper trough in the western provinces of Canada has been a persistent negative driver and with each passing system we are risking a bad outcome. The days leading up to telefest weekend are appear especially troublesome since both ensembles show a strong signature for zonal flow with the anomalous warmth centered over the northeast. Sorry to be the bearer of bad news but we may be forced hope to minimize the damage. Such a task is feasible if the warm weather is accompanied by sunshine and minimal rain and the jury on that is still out.

Is this it for winter ?
Actually, I think winter still has something left. I am still watching the Arctic Oscillation carefully and although it is forecast to go positive briefly it may not remain as such. For much of the country this may not mean much but I do think the weather remains interchangeable or more specifically, I don't think that any warm weather late next week or on Telefest weekend is permanent across the North Country. Unfortunately the pattern looks something short of sustained cold and snowy which simply means that after March 8th, we may have to look individually for the warm and sunny or occasionally snowy days. Remember the healthy MRG base when combined with the warm weather is a nice and welcomed combination late in the season.

Monday, February 26, 2007

Some good news to report for early March

The update for the March 2nd to March 5th period is a positive (mostly) one I am happy to report. This will be the second in a succession of juicy systems to exit the Rockies in a 5-day period. Model guidance has hinted in both cases that warmer air in the troposphere's middle layers will change precipitation to the dreaded icy mixture, particularly freezing rain. In the first case, the system weakened and passed way to the south and we will be lucky if we squeeze out a few terrain induced inches Tuesday and Wednesday. I will take dry weather over ice any day however and we have now successfully kept the rain and ice away from MRG for 41 consecutive days dating back to the MLK day where snow changed to sleet and freezing rain for a few hours before ending. This next system is also poised to trigger a huge northward push of mid-level warmth into the region Friday threatening to end the streak. The situation however looks far better than it did a few days ago.

March 2nd - 5th details
Like its predecessor as this storm pushes east through the Midwest, a second low pressure area will try and intensify very quickly off the Atlantic Coast and act to thwart some of mid-level warming across interior New England. In this case the task will prove to be a bit more difficult unfortunately since this system will track farther north effectively bringing both the moisture and some of the warmer temperatures at the surface and aloft to Stark Mountain and MRG. It is a very close call at this time and the outcome could go either way. At this time it looks as if precipitation would develop Thursday Night into Friday morning as snow then change to a mixture of mostly sleet and perhaps some freezing rain. The American Model would suggest a better outcome with more snow and less ice out of this initial batch of precipitation. The European however has taken the American to the cleaners all winter in the 3-5 day period and is suggesting a warmer less snow more ice outcome out of Friday's precipitation. I am not sure what to think about the disagreement, I know its a critical one but we will have to iron out these differences on Wednesday with a subsequent update. There is some good news in that even the worst case scenario does not include a lot of freezing rain. The real good news is that some of the good dynamics associated with this fairly intense system will settle near the region during the weekend and for a good part of the first full week in March. This could very well mean some hefty terrain induce snow amounts beginning on Saturday and persisting through Tuesday March 6th. In summary, whether sleet/freezing rain falls at MRG or no on Friday, the next week appears very promising as far as skiing goes.

Nothing new in the longer range
I have nothing new to report as far as the longer range is concerned. Indications are that much of the country will see spring-like temperatures in a week to ten days. Across interior New England, it will be a mix of warmer than average and colder than average temperatures.

Friday, February 23, 2007

February to end without one drop of rain or ice, March is up for grabs

No ice or rain early next week but although one battle appears won another will need to be fought between the 2nd and 4th of March. As I mentioned in previous posts, we already have one unfavorable force driving the weather pattern which is the general troughing across western North America or the negative PNA, but by early March more teleconnection indicators will turn against us and may have us on our heals by the first full week of the month. I am not at all calling the situation dire as we may yet find ways to fend off most of the trouble through even March 10th, but ominous it remains.

A mainly dry weekend
The airmass this weekend will keep temperatures below freezing, but it is a very stable one. As a result, terrain enhanced snow will be kept to a minimum Friday Night and Saturday and any clouds Sunday will of the high variety and non-snowfall producing. The high winds Friday will diminish somewhat by Saturday and completely by Sunday. Temperatures meanwhile will climb close to 20 Saturday and well into the 20's by Sunday.

Early next week
The situation for early next week has now come full circle. Downstream blocking in the jet stream is now going to suppress much of the moisture from the storm which, not more than a few days ago, was predicted by many models to produce ice and even rain for MRG. This storm is a strong one as it moves out of the Rockies today but the system will mature too quickly and begin to lose steam as it advances into the Ohio Valley. A second low is expected along the Atlantic Coast and spread precipitation into New Jersey or southern New England Sunday night or Monday but this moisture is not expected to make its way farther north. Eventually as the storms original upper level support moves into the northeast, chances for snowfall increase, particularly in the high country. If this occurs, it will not do so until late Monday or Tuesday and we will have to hope that some lingering moisture is there to be had. The chances for any new snow from this "upper level support" continue into Wednesday before high pressure dries it out.

The move into March
I have gotten a lot of emails about early March and for good reason. Typically it is a great time to ski MRG since the base usually peaks in the first two weeks of the month. Using the Mt. Mansfield snow stick as a reference, we look to be in fairly good shape going into March 2007 (above normal base) but things can turn in either direction in a big hurry depending on whatever weather decides to prevail. The events of March 2nd to 4th appear to be one very important "up for grabs" situation. If you type the Waitsfield (05673) zipcode into weather.com you will get a 10 day forecast which advertises rain/snow showers for Friday the 2nd and plain rain showers for Saturday the March 3rd which hardly does justice to the scope of the event. Weather.com 10-day forecasts are derived from The Weather Channel extended maps which are in turn derived from a computer algorithm which takes actual model data and spits out 2-4 word weather answer for the day. It's an impressive process actually that a good friend of mine from college helped to develop and continue to develop. One of the reasons for the blog was to help us skiing enthusiasts dig a little deeper for answers since 2-4 word answers rarely give us the detail we would like to see or an accurate possibility range. The storm late next week could actually turn out to be an intense one and at this time models are suggesting it tracks anywhere between the St Lawrence Valley (ugh !) and the southern New England Coast (better !). The St. Lawrence Valley track would mean ice, perhaps even rain while a track farther south could produce signficant amounts of new snow. The downstream blocking which played a key role in shunting the Monday-Tuesday event southward will shift west and take-up most of the northern Province of Quebec by this time (The NAO is therefore expected to turn slightly positive). I am hoping, even praying that the storm will simply undercut the blocking in Quebec and therefore turn into the snow producer we would all love it to become. I actually do think this occurs to some degree but can't rule out a period of icy precipitation Friday or Saturday as our worst case. Even this worst case would mean a turn to accumulating snow during the weekend.

General thoughts on the pattern in early March
After watching the ensemble data over the last few days I have decided that much of the country will see mild, spring-like above normal temperaures for the first full week in March (March 4th -11th). The exception to this will be the Rockies where a trough will amplify bringing snow to many ski areas there and northern New England which will sit on the southern fringe of colder weather which is expected to remain across Canada. I say this because there are high lattitude blocking mechanisms but barring a change, will be positioned in all of the wrong areas for below normal Eastern U.S. temperatures which goes along with the teleconnection indicators which will be generally unfavorable. The ensembles, warm as they may be for areas of the central and eastern U.S. south of 40 degrees north are not especially warm north of this line and are actually cold north of 50 north lattitude. I therefore think the outcome will be a battle between warm and cold over the northeast and this usually means weather of many varieties over the span of a week. More clarification on this will come next week.

The Quick Summary
One ice storm is avoided early next week, but another close call looms for the period March 2nd -4th as the weather pattern has clearly moved away from the completely favorable mode.

Wednesday, February 21, 2007

A real chance to save next week

Combustion has gotten the best of the first part of this week's forecast. In addition I promised an update on next week on Monday and failed to get to that. Obviously it is time to make amends with an update for the balance of the week into the weekend and an update on next week and March. I apologize for the delay (and the bust) but the good news and part of the reason for the delay was the recent purchase of a MacBook which will allow for more easier updates while traveling and in most cases skiing at MRG. More good news involves the forecast for next week which appeared threatening a few days ago, but the NAO is fighting very hard on our behalf and is turning what looked to be an ice to rain event to a very close call early next week with new snow now making up a good part of the possibility range.

An update to the busted forecast for this week
12-28 inches was the prognostication on Monday for the period Tuesday through Friday. It is clear that the prospects for the aforementioned appears in serious peril but new snowfall on Thursday and Thursday night will make up some of the ground. The culprit is a dynamically impressive clipper system which will vigorously carve a trough for the weekend in addition to the new snow. The storm will also bring new snow to Boston and the Cape, two areas which have seen amazingly little snowfall (less than 10 inches as of now for the year). As far as MRG is concerned we are on the northern edge of this rapidly digging system and although the dynamics appear impressive, moisture will be somewhat limited until this storm makes it to the coast. Snow will begin late in the day Thursday and continue through much of the night. It will be enough to re-freshen conditions but will amount to 5 inches or less (2-5 lets say) by first tracks time Friday. Models are hinting at some additional terrain enhanced snow late Friday into early Saturday but the unstable layer appears very shallow during this period based on forecast soundings making the prospects for significant snowfall in this time frame very low. If we do get some light snow Friday night and early Saturday, my guess is that it amounts to less than 2 inches but we will see. The rest of the weekend meanwhile will be dry. Sunshine should make an appearance at least late in the day Saturday although it will be chilly and blustery with high temperatures in the teens. Clouds will overspread the region again Sunday although it will not be as cold with temperatures climbing well into the 20's.

And finally for early next week...
A few days ago, ensemble data was indicating trouble, trouble and trouble for early next week. I reflected this concern in the last post on Monday although failed to expand on this as promised (again I apologize). The models themselves have been a lot more willy nilly and have generally failed at giving us any conclusive solution for early next week until today although there were plenty of runs showing ice and rain before a return to colder weather. In spite of the western trough which has materialized as expected, the forcing of the AO and NAO, both of which are negative, are making it extremely difficult for systems in the Rockies to take the nauseating St Lawrence Valley route to the maritimes. Instead, the systems try to cut north then re-form off the Atlantic coast thus choking off attempts to get warm air into the region. In the end what looked like trouble turns into more new snow which is amazing. We are not totally out of the woods here since the threat of mid-level warming still exists which would thus change any snow to sleet or ice for a time. The just released European however hammers home the point that much of the precipitation early next week is indeed snow which according to this solution would fall intermittently between Sunday night and early Wednesday. The system impacting the region has some moisture but is fairly disorganized (at least initially) so snowfall amounts are very hard to predict at this point. The moral of the story though is a positive one overall since we have a real good shot of escaping an ice or rain event early next week and instead getting at least a fresh few inches of new snow. Stay tuned for the final call on this one which should come no later than a few days hence.

And now to early March
Ensembles seem confident in the idea that the first few days in March sees a temporary weakening of the trough in the west while at the same time a not so insignificant trough amplifies across the eastern States. This is certainly some good news for late next week and into the first full weekend in March but the indicators are increasingly bearish going forward with all of the major teleconnection indicators moving to neutral or unfavorable by next weekend. The AO (Arctic Oscillation) is the most significant since its recent negative index has been a positive force on our weather and is expected to switch in sign in the next 7-10 days. In addition to that is the trough which is expected to remain in place across western Canada which will conspire with the then positive AO and become a strong force for zonal flow across much of the country around the time of March 4th. This could very well mean a thaw by the first full weekend in March over a huge span of the nation. The silver lining is that the Ensembles, though they show a warm signal for a good part of the nation in this time frame, are not especially warm in New England where normal is the indication based strictly on the interpretation of jet stream anomalies. We will see how it evolves over time but I am certainly less than thrilled with how the first full week in March (4th-11th) appears. With that said extending this period of great ski weather to the first full weekend in March is certainly a bonus and the active weather pattern should continue until then which will mean the chance for another storm during or just prior to the weekend of the (3rd and 4th).

The Quick Summary
In spite of the lack of new snow over the last few days, some is expected late Thursday. Good news for early next week with a real possibility of escaping a possible ice storm and instead receiving new snow.

Monday, February 19, 2007

NAO turns this week to gold, next week more of a challenge

Some of the disconcerting changes occurring in the west are going to have a large impact the coverage of below normal temperatures in eastern North America which has managed to survive for several consecutive weeks. With the below normal cold relinquishing its grip, we need to stiffen our defenses and come up with a way protect our base if not add to it. As if on queue, the NAO driven by a strengthening ridge over Greenland will help the already negative AO to help turn what could have been a late February thaw into winter wonderland full of powder days and below freezing temperatures. Although I have never been able to alter the weather outcome, I dialed 911 for this one and it felt as if I got a response. As good as it will be this week, trouble looms for early next week and will need more last minute assistance if not a magic act to avoid what looks to be an ice/rain event.

Powder days - We just can't get enough
2005 produced a golden period of skiing beginning in mid-February and lasting through about mid-march but it has been awhile since I remember the stars aligning so favorably for president's week. MRG more or less doubled its seasonal snowfall in the two weeks leading up to the holiday and now we watch as the clipper train nears the station. Two clipper systems this week will ensure at least 2 powder days in the period beginning Tuesday and ending Friday and if were lucky we'll get three. Snow from the first clipper system will arrive early Tuesday morning and will persist through much of the day albeit light. This first system is a weak one but is also a two part series with additional moisture arriving Tuesday night bringing more new snow by first tracks time on Wednesday. Snow from the clipper "hybrid" will be over with during the day Wednesday and any snow Wednesday night into early Thursday will be of the terrain induced variety. Then its the next clipper which will bring a burst of snow Thursday evening into early Friday. This system is more potent dynamically but less so from the standpoint of moisture. It will nonetheless snow, enough to produce another powder day for Friday and thus finishing off one heck of a week for us. Since it is a holiday week with many planning to ski lets have fun with some snowfall predictions. This endeavor requires the "subject to bust" disclaimer but I can limit the damage somewhat by giving a healthy range.

New Snowfall....
By first tracks Tuesday 1-3 inches (an additional 1-3 during the day)
By first tracks Wednesday 3-6 inches (an additional 1-3 during the day)
By first tracks Thursday 1-3 (flurries during the day)
By first tracks Friday 4-7 (an additional 1-3 during the day).

This adds up to 12-28 inches over a 4 day period. Thank you NAO !!!

The upcoming weekend looks especially dry in fact with temperatures running at or slightly below normal. Normal temperatures during the last weekend of February are in the middle 20's on the mountain and low temperatures are near 10. If ice or rain is our fate for early next week, it might be a good time to get out make those turns in the woods before we get that hard crust.

I'll have the full update on next week later today. Enjoy the powder.




Thursday, February 15, 2007

President's Holiday greatness and then a pattern shift

The public information statement from the National Weather Service in Burlington will have storm totals from around the region if anybody is interested. Many reports will come from valley locations, the higher terrain including ski country did even better.

http://www.srh.noaa.gov/data/BTV/PNSBTV
We have now officially erased what was the equivalent of a 20 point deficit in a basketball game and hold a lead as we proceed to crunch time. It has taken 32 consecutive days of below freezing temperatures at MRG, several small storms and then one very big one to complete the deal but we now have established an above normal base leading into President's day holiday. Give mother nature a pat on the back but we don't want her to get complacent. After a glorious weekend with additional chances for fresh powder there are forecast challenges and shades of grey by the time we reach the last weekend in February.

Memorable Presidents Day holiday - very cold however for Monday
It will be cold and blustery through Friday with temperatures on the mountain struggling to make it past 10. Saturday should see some moderation as temps climb into the teen with less winds. Skiing in powder is a great way to stay warm over the next few days and terrain induced snow beginning late Thursday will add to the almost 70 inches of snow which has fallen at MRG in the last week. If i try to get too specific about what is going to fall and when I will surely confuse everyone and bust all at the same time. Lets just say that in the time frame beginning Thursday evening and ending Saturday morning we could see an additional 4-10 inches with the wide ride range accounting not only for uncertainty but also elevation on the mountain. At some point on Saturday a break in the snow is likely as clipper passes well to our south and acts to stablilize the lowest 8,000 feet of the atmosphere. Once the clipper clears the east coast Sunday it will allow another impulse to take aim on the region late Sunday which could bring a burst of terrain enhanced snow and another 5-10 inches by Monday morning. Although a powder day appears very likely on Monday, it will be windy and very cold with temperatures at least 10 below in the morning and struggling to make it above zero during the afternoon. So in summary, we have new snow predicted for lift opening on 3 out of the 4 days between Friday and Monday. Friday and Monday are cold and blustery, Saturday and Sunday are not as cold.

A new pattern to emerge
As next week progresses, the pattern across the entire U.S. will to begin to respond to the pronounced changes across western North America. The ridge over B.C. which triggered the intense cold across the Midwest and East Coast will be replaced by a large trough. Western ski resorts from California to Colorado will surely have a lot to brag about by the last weekend in February. We, on the other hand have to start playing defense because troughing in the west means there will be a real driving force to push warm air northward over the East and Midwest. Is there some good news here ? Yes. This pattern change is not being driven by the AO index which is expected to stay on the negative side of zero over the next two weeks. Ridging across Greenland will also help to counteract any warm-up. This is distinctly different to the situation in early December when every possible indicator was saying warm and snow-less for weeks on end. Additional help comes from the cold Great Lakes. All 5 have some ice on them and Lake Erie is now completely frozen. A broad area of snow cover also helps although the snow cover now is not all that unusual for this time of the year.

The forecast for next week - A significant temperature moderation
So here it is. Tuesday's temps will moderate significantly and there could be some warm advection light snow leading to a light accumulation. A much stronger southern branch storm will then progress eastward on Wednesday and Thursday and the concern here is that there is not much cold air left for it to work with. It may in the end turn out to be so cut off from the receding polar jet, that its impact on Vermont is minimal. If it does proceed northward and affects New England, more snow could be in the forecast but temperatures will be a lot closer to freezing. Overall I still think its a very good week to ski but we will start to notice the changes in the pattern by the middle of the week.

Rest of February
The very unsettled western U.S. is likely to send more very moist and potent systems eastward through the end of February. We are going to lean heavily on the NAO and specifically the ridging in Greenland to help prevent these systems from taking that abominable track up the St. Lawrence Valley. The positive angle here is that the region is likely to see another significant snowfall from a strong storm. The negative angle is that we are unlikely to win every battle and may have to deal with precipitation other than snow at some point before the month ends. With all that said, I am fairly optimistic and think we could make out okay over the next two week in spite of the gradual loss of our cold.

The Quick Summary
Snow, snow and more snow through Monday (President's day) . After a brutally cold Monday, a new pattern will assume control, one of less cold and frequent storms which will hopefully bring only snow.

Wednesday, February 14, 2007

40-50 inches !! How's that for a sweet spot

Wind driven snow will continue through about 6 am. Looks like wind's have shifted west of due north so many locations on the spine of the Green Mountains will get see snow totals enhanced because of terrain. It will be difficult to accurately measure because of drifiting but totals at MRG could approach 4 feet before first tracks time Friday. Feel free to report some storm totals tomorrow morning where ever you may be.

Storm Update: The Valentines Day Blizzard of '07 !!!

The storm has commenced and is proceeding as expected as of this morning. Latest indications are that the low pressure center will track almost directly over Providence and Boston then proceed out over the water before again tracking inland again over Downeast Maine. Incredibly, the american model strengthens the storm to 974 mb as it spins into the Canadian Maritimes which in turn means a very tight pressure and temperature gradient across much of New England and thus the blizzard warnings. Temperatures across Vermont are still near zero in many areas as of this morning and will struggle to rise above 10 at MRG through the duration of the storm. In contrast, do not be surprised to see temperatures climb to 60, yes 60 degrees on Nantucket, Marthas Vineyard and parts of the eastern Cape this evening. Its hard to believe that can happen but such makes the incrediants for a big storm in Vermont.

The Sleet Concern
The big concern as far as the forecast goes is the sleet. The mid-layers of the troposphere have been warmer than expected in many areas while surface temperatures have actually been colder than expected. As a result sleet has fallen in many areas which were not expected to see much. Model cross sections tell the story and will certainly do so in this storm. The cross section for Concord, NH shows that a critical layer will rise above freezing later today (2 C) and this evening and precpitation is likely to go to sleet thus holding down total snowfall accumulations.

http://coolwx.com/cgi-bin/getbufr.php?region=NH&stn=KCON&model=nam&time=current&field=tempa

The cross section for Barre-Montpelier is considerably colder and does not show temperatures above freezing at any layer while precipitation falling on Wednesday and Wednesday night. That being said, temperatures are shown to climb to about -2 C (28 degrees) at about the 7,000 foot level this evening (temps at the surface will be much colder).

http://coolwx.com/cgi-bin/getbufr.php?region=VT&stn=KMPV&model=nam&time=current&field=tempa

Considering that temperatures at these levels have been warmer verses the model integrations, it would not be surprising to see a few sleet pellets mix into the precipitation briefly this evening although I do not think it has a significant impact on accumulations. It will be interesting to watch the temperature at Mount Washington, a location which is positioned at the lower part of the temperature inversion. By Wednesday evening, temperatures at the observatory should be 15-20 degrees higher then what MRG's Stark Mountain will be reporting.

2-feet and probably more
In spite of all the above technicalities, the forecast is on track and with the snowfall already being reported at MRG, total accumulations are likely to exceed 2 feet on the mountain. The wind will be a significant isssue if your traveling or skiing later today, tonight and into tomorrow. Winds, although they are calm as of Wednesday morning, will gust to gale force later today on the summits and gust to hurricane force this evening and tonight. No hurricane wind gusts are expected during the day tomorrow but it will remain extremely windy so check madriverglen.com for details on any wind holds.

Monday, February 12, 2007

Strongest winter storm in years to slam MRG !!!

Mother nature is in the process of engineering one of the great skiing comebacks of the last quarter century. At the risk of sounding like I am part of the marketing chorus, I can honestly say that this past Friday was one of the best days I have ever had on Mad River's "single" side. Although some of the snow certainly was wind driven into the trail, I was literally quad deep in powder on Catamount at a little after 9 AM. As much fun as I had on the slopes Friday, what a downer not to be in the mad river valley over the next week because it will spectacular. There were strong indications of a major event going back to early last week for the east coast but for a while, it looked as though any storm would simply add to a lengthy decadal chapter of big snow for coastal areas and a miss for areas deep in interior New England. As the college football analyst Lee Corso likes to say "Not so fast my friend !!!!". We are not going to miss this storm which will bring blizzard like conditions and a huge accumulation of snow to the entire state of Vermont.

A shift in the thinking
The shift in thinking with this storm stems to Sunday where model consensus dramatically moved the track of the storm northward and westward. Again, the American Model lagged behind the trend setting European model. Also recall the mention in the last post of the extended Canadian model which also tracked the storm farther north and west last week and was predicting a big hit for us. The Canadian Model is probably the least credible of the three major medium range models but that doesn't automatically make it wrong.

Wow !!! What a storm
It will be lengthy and time consuming to get bogged down in details regarding the manifestation of this storm and the forecast for MRG and much of Vermont is actually not that complicated: snow and lots of it ! A little perspective always makes for good reading however and it is worth mentioning that meteorologically speaking, this will be one of the strongest storms to impact the region in perhaps a decade. The term "bombing" is used to describe the rapid deepening (or strengthening) a nor'easter under goes as it achieves maturity usually somewhere along the New England coast. Well, they certainly called in the air force for this one because by the time this surface low reaches the Maine coast late Wednesday many of the off-shore buoys will be reporting sea level pressures of near or less than 980 mb. To put this in perspective, both Hurricane Bob and Hurricane Gloria crossed eastern Massachusetts with SLP's of about 965 mb and both did significant damage to coastal New England. Katrina made landfall east of New Orleans with an SLP of 920 certainly proving how devastating an extra 40 - 50 mb of strength can be.

A Forecast Please !!! - 20-40 inches in case you are sick of reading
The rate of deepening and eventual intensity of the low pressure center associated with the storm have a lot to say about snowfall amounts in Vermont. The track of the storm also dictates snowfall amounts to a large degree and for big snow across the northern Green Mountains, it is best that the storms track very close to the city of Boston which is exactly what this storm is going to do. So without further delay lets make a forecast. The snow in all its glory will probably not begin until after midnight Wednesday but could be falling at the rate of 2-3 inches per hour by the time lifts open Wednesday. Get their early if you want to truly enjoy it because we will see an big increase in winds during the afternoon which will produce blizzard-like conditions not only at the mountain but all across the state. At the summits, wind gusts will reach gale force during the afternoon and even hurricane force later Wednesday evening. The heavier snowfall will taper to snow showers early Thursday but winds will remain strong as it turns colder. Check madriverglen.com for updates on any wind hold situations. I find MRG to be particularly good about letting us know about any lift closures and I am sure the guys will come through again. As for total snowfall accumulations, I would forecast more but the storm will be moving along at a brisk pace and prevent any historic 2001-like snow. That being said Model QPF is spitting out anywhere from an 1.5 to over 2 inches of liquid which is something else I haven't seen in a while over Vermont in winter. This translates to over 2 feet of snow at the mountain but I am going to give a conservative range of 20-40 inches with a lot of drifting. It won't be the fluffy terrain induced or champlain induced powder. The synoptic snow typically has a higher density but it will be powder all the same and will make for some great skiing to be sure.

Holiday Weekend
Every weekend at MRG in the last month seems to surpass its predecessor and this weekend will be in keeping with the trend. Terrain induced snow will bring a few more inches to the northern Green's by early Friday and the intermittent snow showers will continue through early Saturday on brisk winds. After successive days (Thursday and Friday) with temperatures not much better than zero on the mountain, Saturday will be less extreme and less windy as an clipper digs into the Jet Stream and passes well to our south. I'll update our terrain induced snowfall prospects later this week for the weekend but it looks as though we could get at least a little new snow for lift opening both Friday and Saturday and possible Sunday as well.

Presidents Day Holiday Week
The first half of presidents day holiday week looks golden. The second in a series of clipper systems will impact the region early next week bringing the potential for some new snow although its difficult to say exactly when at this stage of the game. Temps will be very cold Monday (President's day) and will moderate as the week progresses although temperature moderation are never linear in New England and it would be smart to plan for at least one more very cold day outside of Monday. By next week, the very ridge which initiated the outbreak of cold over the western provinces of Canada will be replaced by a trough and some very unsettled weather which will extend through much of the western United States. This will be an adverse force in our weather as we head toward the last weekend of February and into early March but next week, the week in question is safe. The good news is that both the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) are shown to remain at least slightly negative and will hopefully act as a competing and favorable force against the adverse effects of any western trough by the end of the month.

The Quick Summary
Can't ask for much more going into a holiday week. Strongest storm in years will bring heavy snow and high winds to the mountain Wednesday and Thursday. Subsequent to this are additional chances for lighter amounts of snow this weekend and early next week.

Major storm set to strike northern/central Vermont

Biggest storm, on a synoptic scale, in at least 3 years is set to strike Mad River Glen and surrounding Vermont beginning late in the evening on Tuesday and lasting into Thursday. There will be both very heavy snow and high winds. The northern half of Vermont, the White Mountains of New Hampshire and much of Maine look to be in the storms sweet spot where total snowfall based on preliminary indications will be in the 18-36 inch range by late day Thursday. Wow !!! Coastal areas will see lots of sleet/ice and limited snowfall so don't be fooled if the forecast for Boston and New York downplays snowfall accumulations. Their loss is our gain !!

I'll have a full update later today but I have to be careful not to get stricken with storm attention deficit disorder here at work

Wednesday, February 7, 2007

Cold through next week now with more active pattern ready to take over in time for President's Day

I have decided that complaining about a relatively snowless cold pattern is bad karma. December of 1989 was the coldest on record for many locations in eastern North America but the cold was not accompanied by a lot of snow in the northeast. A 13-year old weather nerd named Josh Fox had the nerve to complain about the lack of snow and the winter collapsed and that December was followed by a January and February of near unprecedented warmth and lack of snow. The Mount Mansfield snow depth from that year tells of that tragedy in graphic (no pun intended) detail.

http://www.uvm.edu/~empact/data/gendateplot.php3?table=SummitStation&title=Mount+Mansfield+Summit+Station&xskip=7&xparam=Date&yparam=Depth&year%5B%5D=1989&width=800&height=600&smooth=0&csv=0&totals=0

This years graph still shows us behind as I pointed out a week ago but gradually making up ground. What is more important is that any slight consternation I may have exhibited in the last post about the middle and end of February is now replaced by exuberance and anticipation of what lies ahead. Fears of any precipitation other than snow (I honestly wasn't that fearful) are now gone and the question over the next two weeks will be whether or not northern and central Vermont can score big points in the more stormy pattern which expected to prevail beginning next week.

Through the Upcoming Weekend
There is not much change in the thinking through the weekend. There are two very weak impulses which will spin rapidly around the polar vortex through Friday morning. There is enough low level instability and left-over Lake Ontario moisture to squeeze a few very wind driven inches out over the mountains. The wind, however will make the near zero degree cold feel much worse, particularly on the summits Thursday. Friday should be mostly dry and not quite as cold or as windy and the weather from a temperatures and wind standpoint will improve even more on Saturday (Saturday mountain temps will make it into the teens). A stronger impulse embedded in the polar jet is expected to begin impacting the region during day Saturday. There is very little moisture with this system but a few inches over the high terrain is certainly a reasonable guess at this point. What is more of a challenge is trying to figure out which of the two weekend days will have new snow at lift opening. At this point the snowfall (if any) has the best chance of occurring late in the day or in the evening which would make Sunday the day with new snow at first tracks time (again if any does fall). Saturday will be the better of the two days from a wind and cold standpoint since Sunday's temps are expected to drop accompanied by stronger winds.

Cold Sustains Through Next Week With Talk of East Coast Snow
The first detail that needs to be put in order concerns the temperature moderation idea I put forth for next week in the last post. This suggestion needs to be put to bed at once since the 5 day period beginning Monday the 12th could very well be colder than the same 5 day period beginning this past Monday at MRG. Cold in New England is triggered by different mechanisms then cold across the upper Midwest and the jet confluence zone which is shown to set up over the Canadian Maritimes early next week is one of the biggest drivers of below normal cold across the north country. Even if the wind early next week proves to be less of a factor relative to the upcoming few days, morning temperatures of -10 or -20 will certainly exceed this weeks numbers. The stage is then set for a big east coast snow event as the confluence zone combines with an approaching storm system to produce cold air damming and lots of precipitation. The question for us relates back to whether or not we stay dry in such a set-up as we did in Presidents day 2003 and the Blizzard of 1996 or whether the storm proceeds up the coast and shares the love. A consensus of model guidance suggests the snow falls to our south with the Canadian model being the lone hold-out and showing us getting a big storm. The jury is still deliberating this one and I would not be surprised if we are talking storm by the end of this weekend.

The Presidents Day Holiday has a Very Promising Look
And now a quick word on the overall pattern leading in to the all important President's day holiday. Ideally, the snowiest times at MRG occur when it is cold but without the disruptive force of a massive Polar Jet such as the one which currently exists. Preliminary indications are that we may very well achieve such a goal. The storm next week (middle of next week to be specific) will mark the beginning of a much more active weather pattern. The break-down of the elongated western ridge is the culprit and will lead to a succession of moist weather systems which will cross the country beginning with the system in the middle of next week. The break down of the western ridge means the Polar Jet will relinquish its grip on the country, but very cold arctic air at the surface will remain over much of eastern Canada and continue to be a factor in New England thanks to the AO which is expected to remain negative and a positive jet anomaly signature over Greenland (one driver of the NAO). When you boil this all into a forecast for the Presidents day holiday and subsequent week, it means at least few chances for significant amounts of new snow.

The Quick Summary
Only light amounts of new snow with the wind and cold through Sunday. The temperature for moderation is out for next week and is instead replaced by talk of east coast storms and a more active, snowier pattern ahead.

Monday, February 5, 2007

Frigid temps through the weekend; temperature moderation next week could be an interesting twist

The underscored word of the week is "cold" of a widespread and very intense variety. Many cities across the Midwest are falling below zero for the first time in several years. The cold, in this instance isn't centered around New England. In contrast to what occurred on January 26th, this cold is centered across the upper Midwest where temperatures on a frigid scale are as impressive as December of 2000. At this risk of getting a little geekish, check out this colorful map which shows current temperatures across the country. I like this map because it shows a good percentage of Canada and depicts how the cold is configured around the Great Lakes.

http://twister.sbs.ohio-state.edu/surface/ustemp.gif

General Stark did pick up a dose of new snow, mainly Friday night but I am jealous of the Great Lakes. Those snowbelt areas are embarrassing us, particularly the tughill plateau in New York where some places seem to be picking up 1-2 feet of the good stuff every day. The lake bands this weekend were very condensed as they often are when extremely cold air moves over the lakes from the west-southwest. Whatever was left of the plume of moisture after it crossed the Adirondacks affected a limited area of the northern Green Mountains (Jay Peak). The heaviest snow bands have since shifted south and as of Monday morning there were a few snow showers over Mad River and points south. These could drop 1-3 wind driven inches on the mountain today and tonight so enjoy it if you can endure the cold.

No better than 10-degrees (-12 C) all week and usually much worse
The north country will be free of major weather systems through the weekend; instead, it will remain cold with temperatures failing to make it above 10 on the mountain through most of this week and possibly through the upcoming weekend. There are some small undulations in the intense polar jet as impulses rotate around the vortex of cold which is currently positioned near the Great Lakes. The first such disturbance impacts the region Wednesday or Wednesday night which could provide the high terrain with a re-freshening few inches of powder for Thursday although it doesn't look like much. The passing of this disturbance will allow a build up of brutally cold temperatures in Ontario/Quebec to drain over northern New England and thus create the two coldest and windiest days of the week Thursday and Friday.

First close-up look at the upcoming polar weekend
Model guidance has had difficulty timing some of these smaller weather systems because they are caught in this mammoth polar jet. One such system appears as if it will impact the region this upcoming Saturday but the if, the how, the when and about everything appears up in the air. Its not a significant weather system; but nonetheless, it brings us the chance for much needed new snow on the all important weekend day. The system will arrive as the last of the most intense pieces of the Polar Vortex rotates into the Great Lakes and into New England. This jet has been so incredibly energetic that it has been difficult for any of the smaller short waves (waves within bigger waves) to maintain any real potency and thus the impression prevails that we are under-achieving in this pattern. The capriciousness of the models certainly offers no certainties but its something to watch over the next two days since the outcome of this system may make the difference between a 6 inch snow weekend or a 1-2 inch snow weekend. I can make the determination that Sunday appears the colder and windier of the two weekend days although to reiterate, neither day is likely to see temperatures much past 10 on the mountain if at all.

The Big and Important Long Range Discussion
Beyond the upcoming weekend will bring us to our first potentially adverse situation. For the last few days the ensembles have been keying on the 14th-16th (Wednesday-Friday) of February as a mild group of days based strictly on jet stream anomalies. A big cause of the change will be the elimination of the high amplitude western ridge, which at this point will have migrated to the poles (more on that later). This will allow the western states to become unsettled while much of the eastern half of the country experiences a temperatures moderation. There are strong indications that a significant storm system will gather strength across the south during the middle of next week and then track northeast into the decaying cold air. If the rotting cold were to get scoured out quickly and the storm were to take the worst possible track, we could find ourselves getting precipitation other than snow only a few days after experiencing brutal cold. That being said I in no way think this happens. The break down of the western ridge is likely to occur but much of that blocking migrates to the pole which keeps the AO (Arctic Oscillation) safely in negative territory. The negative index indicates that arctic air is unlikely to give up its grip on the northeast without a drag-it-out fight which is what we want. In other words, what looks like trouble could turn out to be a significant snow producer in the best case scenario.

Someone sent me an email about links to these teleconnection indicators so I will provide a few here.

AO - http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
NAO - http://www.cpc.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif
PNA - http://www.cpc.noaa.gov/products/precip/CWlink/pna/pna.sprd2.gif

After February 16th would bring us to the President's day holiday if I have my calendar correct. The warm-up next week is shown to be temporary and quickly replaced by another surge of below normal temperatures. The return to colder weather has the support of the AO as I mentioned above but there is no indication of a strong ridge in western North America. This would suggest that the cold will not be as intense nor as long in duration. I should be careful however with this statement because the weather becomes increasingly volatile climatologically in late February and early March and although a pattern as a whole may not match up to the last two weeks or next 7 days, individual weather or temperatures events are certainly capable of impressing.

The Quick Summary
Cold dominates through the weekend with new snow falling in small increments. Temperatures try and modify significantly as a storm system approaches next week. That could be bad or good but I am thinking good as far as new snow goes.

Thursday, February 1, 2007

Storm will disappoint but plenty of new snow will fall anyway

The single chair blog has a new background (thanks for the feedback), a new picture (thanks to the google image search) and now all we need is new snow. We did find a little of that Wednesday Night to freshen things up but I have set the bar high for the weekend and we would like it to deliver. A storm is gathering strength in the southeast and is preparing to take a take its moisture up the coast. Snow enthusiasts had high hopes for this storm but in spite of its rich moisture, it is weak dynamically and will fail to make much of a dent in the overwhelming strength of the polar jet gripping the country. This storm is like me taking my canoe across a flooded and raging river. I might make to the other side but by the time I do I will be way downstream. Fortunately for us, we have other important factors working in our favor which should make up what was lost with this storm and most importantly conspire to create a fantastic ski weekend.

Winter Storm update
The aforementioned storm is actually not a total loss. It will provide many of the east coast cities with a quick hit of snow, ice or rain Thursday Night into Friday before exploding in the Canadian Maritimes. Although Central and Northern Vermont will stay out of the way of the deep moisture, computer guidance does suggest that the precipitation shield will expand into the region for a time beginning either during the late morning or early afternoon Friday. The last National Weather Service forecast for the region suggested as much predicting snow for Friday afternoon (accumulation around an inch). On the mountain itself it is still reasonable to expect a few inches, lets say 2-4, by late Friday evening.

Weekend new snow update
Whatever snow does fall Friday will be followed by a break in activity associated with an area of subsidence which I eluded to in the last post. Forecast soundings suggest that this occurs Saturday morning and would therefore mean that the few inches which falls Friday and Friday evening will account for any re-freshening by first tracks time on Saturday morning. It will quickly get interesting though as the day progresses. As the polar vortex drops south toward the Great Lakes, the relative warmth of the lakes will induce or maintain a very slow moving low pressure center. This feature will help align the winds for what should be a fun terrain induced snow event beginning during the day Saturday and lasting through most of the day Sunday. There will be heavier bursts of snow as meso-scale surface waves swing through the north country. By Sunday evening, the three-day snow total could still very well exceed 10 inches. I would be inclined to be a bit bolder on the snow totals except the winds will be west-southwesterly this weekend which takes the Champlain enhanced stuff up toward Jay Peak. MRG also gets shadowed somewhat by the Adirondack mountains although Lake Ontario and even Lake Erie moisture has been known to re-emerge over Stark Mountain after missing the Champlain valley. Temps by the way will be in the teens Saturday and single numbers Sunday. In spite of the cold and the wind on Sunday, I think it will be the best ski day of the year.

Next Week: Cold but will snow showers continue
Next week will be dominated by cold weather not only in Vermont but across much of the eastern two thirds of the country. High temperatures on the mountain during the Monday through Thursday period will struggle to climb above zero and there will be wind to deal with all of the days. No organized storm system is expected to impact the region in this aforementioned period but snow showers may or may not be a factor through a good part of next week. The question relates back to what I refer to as the Lake Ontario cold axis which often divides New England during severe cold waves. Cold weather can enter Vermont either from a region south of or over the Great Lakes. This type of cold weather contains more moisture more instability and is rarely record-breaking. The cold which pushes in from eastern Canada is more stable and can be record breaking. The former usually is accompanied by terrain induced snow showers the latter is a dry and stable cold. Models at this time suggest the former and a continuation of snow showers through the first half of next week. I remain skeptical and think snow showers shut off for a time after Monday. I'll have an answer by late this weekend for sure.

Longer view relatively unchanged
The longer range involves the weekend of the 10th/11th and beyond. Much below normal temperatures are still likely to prevail through at least February 12th thus taking us through next weekend. Although arctic air masses will continue to drill deep into the U.S. the relaxing of the polar jet, which will begin late next week may allow for another shot at an organized storm system in the next weekend time frame. Whether it be from a garden variety Alberta Clipper or something else, it will at the very least, produce another long-winded weather discussion by yours truly. This so-called Polar Jet relaxing will continue in to the middle part of February but some key teleconnection indicators, such as the AO, remain favorable and have me of the opinion that we stay out of any adversity through Presidents Day although its is very, very early.

The Quick Summary
New snow mainly from terrain effects and not the storm will create a great weekend of skiing, possibly the best day of the year Sunday. Very cold weather still on the horizon for next week.