Snow prospects look better, while thaw looks brief and less intense

SCWB entries have been full of good news over the last few weeks and it was expected that the positive vibes might end with the current entry. From a certain point of view I suppose that is so, but from my point of view, weather and forecasting is relative. One expects a certain narrative to play out but when the narrative changes our reaction is based on the nature of that change as opposed to the specifics of the story. At least that is the way it works for me. The end of the upcoming week had and to some degree still has a foul stench to it that one could smell even a week ago. Successive cycles of models have rather significantly mitigated much of the odor. One could speculate as to the reasons why this potential ugly thaw doesn't look as bad. My feeling is that there are two major feedbacks working in our favor and should be for the duration of the season. 1) A massive expanse of snow cover over the Midwest and Northeast 2) A remarkable coverage of ice in the Great Lakes. The latter is particularly noteworthy. 4 out of 5 of the Great Lakes are about completely frozen with Lake Ontario being the last hold out. You have to go back at least to 1994 to see anything remotely close to a situation like this. With much of the Great Lakes ice rather than water, the aggregate lake environment does not have the same impact on the weather map that it would in a typical winter. In the end, cold air masses are consistently winning small battles against surges of warmth and over time, these results make a difference.

Over the next week, almost everything on the weather map looks farther south. We are still expecting a dose of  snow from a "fun of the mill" weather system that should spread the powdery stuff into Vermont early Tuesday. This storm marks a division between very cold arctic air and eastward advancing and milder pacific air. In the end we should see 3-6 inches from this period of snow which should end Tuesday evening. Tuesday's temps will mostly be in the teens. Wednesday will be substantially milder, closer to freezing actually but a weaker disturbance will keep clouds in the region and more snow, maybe even an inch or two. Amazing, but a day that looked very much like a very mild day, now could at least partially turn into a powder day. Thursday will dry and above freezing temperatures in the afternoon should finally remind us that March is just around the corner.

What's left of the "odorous" stank occurs Thursday night and Friday. By this point a large upper ridge covering the eastern half of the country will guide a well organized storm system deep into Quebec. Rain or freezing rain should develop Thursday night and we should certainly see a period of all rain Friday, at least a half an inch of the liquid stuff. Temperatures could briefly surge from the 30's Thursday night, all the way to 50 Friday but the mild intrusion will actually be short lived and colder weather will begin displacing this warmth by Friday evening.

Models have been hinting, several times actually, at a storm for the weekend of the 22nd and 23rd. Although the warm ridge gets beaten back late Friday it will not disappear entirely. A storm system will again be guided up the slope of this upper ridge somewhere in the vicinity of New England. A few days ago, this appeared to be the second part of a potentially damaging thaw and perhaps another rain event. Again, in the last few days everything looks farther south and as the jet loosens in the Pacific by the 22nd, cold arctic appears like it wants to make a more efficient southeast advance, perhaps fueled by some of the feedbacks discussed above. If the cold proves to be a significant player in this evolving weekend event, and there is every indication that it will be just that, precipitation from this storm has a much better chance of falling as snow. As of now, models are still having a tough time with this system and whether or not it exists at all. As of now, I am certainly a lot less worried about a 2nd round of rain.

Cold weather fueled by the reemergence of a positive PNA and a loosened jet in the Pacific will likely dominate the back 6 days of February. Beyond the weekend, we could see some more snow from either a passing clipper system or simply from terrain induced snow showers. During the last day or two of February into very early March there are some more signs of splitting in the flow and some resulting active weather.

Bombogenesis II and some additional snow likely for Tuesday

Lots going on and lots more is expected to happen in the coming week and lots of people have plans to be at the mountain in the coming days I am sure. ”Bombogenesis – The Sequel” will indeed happen and although it will not mean another 1-2 feet of snow for the mountain, I expect we get some Saturday. The catalyst is another very potent upper air impulse and a much weaker surface feature. By Saturday morning however, the dynamics in the atmosphere are such that even an initially weaker storm will see explosive development south of Long Island, ultimately deepening again to sub-980 mb northeast of Cape Cod. The track of this system is too far east for big snow across much of VT although much of eastern Mass and all of eastern Maine will get a big taste Saturday night. The explosive development of  this storm will allow for the precipitation shield to expand west into Vermont however, at least the section capable of producing an extended period of lighter snows. Northwest flow later Saturday will also encourage some terrain enhancement and I would expect a few inches Saturday and Saturday evening. 

The door will then swing open for a sneak attack of arctic cold and interior New England will get the brunt of this airmass. Sunday will be a blustery day with more snow flurries. Temperatures will start in the teens but end up in the single digits later in the day. Monday morning, Presidents Day, will feature less wind  and better visibility but readings will be below zero in the morning and struggle into the teens later in the day. 

Our next storm system is looking better and better as far as snow is concerned. This is a warm advection type of event with a front marking the division between arctic and pacific air. The frontogentics in these types of situations can be quite productive for snow and I expect this to bet the case with this very garden variety system on Tuesday. Snow should begin late Monday night or early Tuesday morning and persist though a good chunk of the ski day. I am feeling pretty good about several additional inches. 

Beyond Tuesday lies lots of Pacific air and the milder temperatures.  Readings should inch above the freezing mark Wednesday but I expect 2 days in the 40’s and 1 in the 50’s at the very least between Thursday Feb 20 and Sunday the 23^rd. There is likely a rain event of some sort looming in this horizon as well. The warm weather keep the snow soft in that time frame but to keep the snow soft at the end of February we will need some more help. There are signs beyond the 23^rd that another positive PNA regime emerges with intrusions of arctic cold that should keep the mountain sub-freezing through the last week of the month and perhaps into early March as well.

Valentines Day Storm 2014 and all it's goodies

Snowflakes are flying across Vermont so more or less, the party has started. Even as we have inched closer to the event time, high resolution models have struggled with this relatively compact storm. This is understandable since there are some rather intriguing intricacies. Most importantly, it is a narrow area stretching from eastern Pennsylvania, to the Catskills of New York northeastward to the spine of the Green Mountains that should see the best snow. A few days ago this seemed possible with some loose consensus suggesting such, now it seems likely.

The biggest concern I have had and still have relates to the play by play during the storm. Radar imagery as of Thursday afternoon indicates an area of heavy snow moving northeastward through New England, behind that a large dry slot where no precipitation has fallen. This initial batch of snow has been very impressive dumping 3 and even 4 inch an hour snows from eastern PA to much of Mass but the strengthening low pressure responsible for this is moving a bit out in front of the deepening upper air support. This essentially means that MRG and surroundings is in store for an initial burst of snow Thursday afternoon. During the evening and into the early part of the overnight some dry air could get entrained into this initial conveyor of moisture resulting in a several hour period of lighter, less than 1 inch per hour snow. This deepening and very intense and quite closed piece of upper air support will ultimately win the day. Almost like a puppy on a leash, the aforementioned jet stream feature will give our winter storm a yank and prevent it from advancing too far to the northeast. In the end, a much more consolidated low pressure center will explode near the small strip of New Hampshire coastline to sub 980 mb. The associated precipitation shield or snow shield will likewise intensify. Some of the higher resolution simulations in the last 12 hours have really driven this point home. The snowfall intensities in the pre-dawn hours are indicated to be almost historic and in some cases really hard to believe. Take what is indicated and cut it in half and we could still see 2-3 inch an hour snowfall rates for a period of about 3 hours right at or just before dawn Friday. With that said, I am all in for our 15-30 inch storm total with the snow tapering to flurries in the afternoon. 

A couple of other things that should address some emails and other FAQ’s.

1)    I would not be surprised to see a minimal amount of sleet in the overnight hours Friday. There is a small near freezing layer in the lower troposphere that would only be an issue given very light precipitation. Once our bombogenesis is underway early Friday morning, it is all heavy snow all the time. 

2)    Snow consistency should stay of the powdery variety although at least initially, it will be of the denser powdery variety. By Friday morning, the snow should become more fluffy thanks to a more favorable dendrite growth environment in the later hours of this storm. Temperatures will be in the 20’s during most of this event but should stay far enough from 30 to prevent too much in the way of wetness in the snow. 

3)    This is a big one and I might get in trouble for speculating but what the heck. With any “bombogenesis” there will be wind, lots of wind. Vermont will be no exception. Winds are expected to be very strong particularly early Friday. As far as the Single Chair goes the wind holds are primarily associated with a prevailing east wind. The wind will be ferocious, gusting to 50 at the summits but it will be well north of east in direction, primarily north and then northwest later Friday. I am not making any promises and there are probably guys on the mountain that no more than I do about it and if they feel the need to chime in and scold me please do so. 

We also have another weather system Friday that will ultimately track slightly east of Cape Cod. It’s reinforcing area of upper air support however should mean additional snows Saturday, several inches I think. 

Lastly, this should be one of the best weekends at MRG in a few years so please get out there and get some. That being said, stay safe on the roads. The driving Friday morning, particularly early Friday morning, will be awful with low visibility, blowing snow and drifting on the roads. Plan around this if you can and please enjoy.

Big time east coast storm may be saving its best shot for Vermont !!

A couple of days away from a reliable internet connection and in that time there was all sorts of rioting amongst forecast models in regards to our late week storm. For once, we have a well organized, maturing southern branch feature, loaded with moisture, poised to move up the eastern seaboard in the  midst of an  amplified jet pattern. The result will be a very intense, yet compact winter storm. Since the east coast media has become hyper-focused on these storms, there has been a lot of opinions, forecast maps and some crazy proclamations all of which  have seemed to change from one day to the next. The expected strong intensity combined with this distinctively compressed personality will make the forecast a challenge particularly along the immediate east coast. For Vermont, however, much of the fogginess in the forecast consensus has cleared and I expect the the best storm of the year, perhaps in 3 years late Thursday into Thursday night.

By Thursday morning, a maturing low pressure center west of Cape Hatteras will spread rain and snow to the Mid-Atlantic and continue tracking toward eastern New England Thursday night. As it does, the storm will continue to deepen, perhaps to 980 mb as it enters the Gulf of Maine early Friday. There will be a very tight corridor of intense snowfall and although some disagreement remains as to what corridor gets this snow, the spine of the Green Mountains is the favored area in my opinion. Snow will begin late in the day Thursday and become very intense during the overnight hours with 2 and 3 inch snowfall rates, and perhaps even some thunder in a few spots. The center of the storm will elongate vertically during the overnight hours and warm, above freezing air will get thrown westward into coastal regions and well into New Hampshire. Low lying areas of Vermont, particularly the Connecticut River valley could see some mixed precipitation, coastal sections of New England will see a change to rain, but the high country of Vermont should just see snow, heavy snow in fact. If the storm wasn't moving at such a brisk clip I would throw out the 2-foot plus forecast but for now lets call it 15-30 by Friday afternoon.

A tightening jet in the Pacific will bring a second yet potent system that will effectively re-amplify the pattern for Saturday. The system will not have much in the way of moisture to work as the core of the upper air impulse moves into West Virginia Friday night; but as it proceeds to the coast, another storm will form and move northeast just off the southern New England coast. The storm will not be strong enough and will not track far enough west for another round of super heavy snow for VT. The large pool of instability associated with this feature however combined with prevailing northwest flow should set the stage of terrain induced snow showers over the mountains. The snow showers should provide a fluffy addition to what should be a very healthy base, perhaps a significant addition of several inches during the day Saturday. Overall the mountain could certainly see one of its beloved 2-3 foot in 3 day type periods, a scenario long overdue for the mountain and well deserved.

Snow showers should continue into Sunday but not quite as intense.  Monday, president's day should feature much more in the way of sunshine and great visibility although it will cold cold with temperatures generally in the teens during much of the ski day. Arctic air will retreat somewhat as next week progresses thanks to this aforementioned tightening of the jet stream in the Pacific. There is however one more weather system that is capable of producing some snowy goodness during the middle of next week. The retreating cold will mean that there is some ice risk with this storm but additional snow is likely, at the very least during that Tuesday/Wednesday time frame.

The risk of a thaw goes way up toward the weekend of the 22nd and 23rd. It looks like a short-lived type of thing but there are plenty of better things to think about right now. Enjoy.

"Model Hugging Syndrome" and a might be storm late in the upcoming week

I have been getting some comments, tweets, emails asking or referring to a specific model at a specific time. It's actually great to see so much nuts and bolts interest in weather forecasting which I know has existed for some time. That being said, weather enthusiasts and closet weather enthusiasts (me included) can be at times stricken with "model hugging syndrome" or "MHS". The "glass half empty" guy will send me a doom and gloom email regarding some model showing rain while the "glass half full" buy will ask me about some model forecasting a 2 foot storm 10 days out. There is so much model to model variability with the output that "MHS" is capable of sending someone to the loony bin. It didn't help when NCEP decided to run the American GFS model 4 times a day even though concrete upper air data is only collected twice a day. The GFS in particular is chaotic even beyond day 5 and the biases and issues with the model need to be corrected by way of improving the physics in the model as opposed to running it a zillion times a day. This however is not a model bashing rant. In spite of biases and flaws, models are capable of performing a massive amount of atmospheric calculations that humans are incapable of and powder hounds certainly should use them to help plan sick days. These calculations can differ quite greatly however because a models run 6 or 12 or 24 hours can interpret either the same or different rounds of upper air data quite differently. It is thus important to look at a collection of data, try to establish a consensus of what the data is showing, making additional adjustments based on known biases, factor in any observations that models might be failing to account for and finally reach some sort of conclusion as to what might happen. In the end, there are lots of moving parts and it always best to expect these parts to move over time.

The decaying piece of the massive Rocky Mountain storm will approach the region Sunday and spread some light snow into most of Vermont Sunday night. The storm will try and get energized off the New England coast but too little too late I think for a big event. A little event is still welcome though and we could squeeze 2-4 inches out of this by the end of the day Monday which should be blustery and chilly with temperatures in the teens. Tuesday will be crisp and cold with sub zero readings in the morning. It should feel nice by the afternoon however with plenty of sunshine and temperatures inching toward 20 degrees. We should see more of the same for Wednesday only a little warmer and perhaps more high clouds late in the day.

The weather map later in the week consists of a southern branch storm that will intensify and move up the Atlantic Coast while a clipper system slowly approaches from the west. We had hoped these two systems might combine to form a monster noreaster by Friday but this may be a stretch. The southern branch storm however should track close to Cape Cod, it appears to be a more compact event but system is certainly capable of bringing a healthy period of snow to MRG and surroundings Thursday. The clipper then arrives Friday with a nice cool pool or instability pool which should kick the snow shower machine into action later Friday into Saturday. Different models are still producing different results Friday; in fact, there is less consensus Saturday than there was 48 hours ago. Still, we do have some consensus for some decent snow leading up to the weekend 15th and 16th.

Ensembles are still indicating a tightening of the jet in the Pacific beyond the 16th. The region has some tepid support from the AO and NAO but recent ensemble data has shifted the core of coldest and most unsettled weather into the western states. That is not a good trend as of this morning but below freezing temperatures should keep any fallen powder, powdery at least through around the 18th of the month. We have to open the door for the possibility of a thaw in the days that follow that.

Weekend storm fizzles but another one is on the horizon

One much needed storm is in the bag and I can report first hand that the mountain skied very well today. I can also report first hand that it is always a good day when a blog entry can be done from the MRG bar in the afternoon with a beer in hand. There has been lots of talk about the potential weekend event and when I talk to fellow skiers and riders it seems they all know about it and already know what is going to happen to it. What the heck am I here for then ;)

It does not look as if things are going to come together quite as we would like over the weekend. Southern branch energy in the jet stream will consolidate off the Carolina coast on Saturday (bringing more snow to DC I am sorry to say since they have no appreciation for it) while a weakening storm exits the eastern Rockies. The weakening system is the piece of energy that we had hoped would take the drivers seat but there are too many chefs in the kitchen I suppose to make this happen. Nonetheless, there is some minimal hope with this decaying system. It will make a last ditch effort at intensifying off the New England coast some snowfall is still possible Sunday into Monday as a result (a light accumulation). In the meantime temperatures will stay on the below side of seasonable thus continuing what has become a building stretch of rain and ice free weather. The Sunday/Monday should've been big snow event will mark another intrusion of colder temperatures but we have seen considerably worse than the readings we will see early next week.

The active weather will continue as promised. It was mentioned in the last update that a late next week snow seemed probable and there is rather good clarity of a relatively organized winter storm late next week. The time frame would be Thursday, a week from now which means lots of fine tunings will be necessary. In the forecasting game however, one loves to see ensembles from separate model packages provide this kind of consensus so early. This consensus includes a storm riding up the coast Thursday spreading snow into New England. In the wake of this storm a nice pool of instability should kick the snow shower machine into gear and set up the weekend of the 15th/16th as the best of the year.

Beyond that, the pattern continues to look active. We will see a tightening of the jet stream in the Pacific but as this is happening the Arctic Oscillation  and North Atlantic Oscillation will turn negative helping to anchor the cold in North America while more storm system cross the country. This should mean more snow to talk about.

A nice 6-12 Wednesday, but is the "big one" poised to unleash it's fury on the 9th/10th ?

Our midweek storm is on track and on target. The system will strengthen along the Gulf Coast Tuesday, move into Tennessee Tuesday night and then quickly transfer much of its surface energy to Jersey coast Wednesday. The system will show some initial potential and certainly has the moisture to move from a  "good" to "great" event when the effects of this storm finally reach VT and vicinity. Ultimately however, this will turn out to be a flatter, very garden variety storm for Vermont although a much needed and much appreciated snowfall. The snow will arrive in the pre-dawn hours Wednesday with a period of heavy snow in the early part of the ski day. Once the storm effectively transfers to the coast however, a relatively strong jet stream will guide much of the moisture and energy out over the ocean. Snow intensity will thus lessen later in the day and taper to flurries during the evening. The best upward motion associated with this system will actually be situated in the southern half to two thirds of Vermont and New Hampshire with sleet and ice across Mass and interior Connecticut. Mad River Glen is thus on the northern edge of what I think will be the best snow. Accumulations will likely be in the 6-12 inch range and the overrunning, frontogenetic, nature of the snow will keep the density a little higher. Most importantly, absolutely positively no rain or ice to deal with.

Thursday should be generally dry, chilly but only slightly blustery. Temperatures will struggle to get out of the teens but February-style sunshine should be a comfortable addition to the ski day.  Expect more clouds over the high country Friday with similar temperatures and some instability flurries and snow showers.

My attention today has turned toward a potential storm this upcoming Sunday and Monday the 9th and 10th of the month. There is a more potent amplification in the jet stream that is expected around this time, and the jet does not appear to be overwhelming enough to crush a potential storm would one develop. And as it turns out, one such storm should develop, forming again along the Gulf Coast and advancing northeast toward the Virginia Tidewater. I gave a shout out to the American GFS model over the weekend (via twitter) since cycles of this model run showed this system exploding through its maturation process and dumping upwards of two feet of snow across interior New England late Sunday into Monday. The heavy snow potential hinges on the storm tracking close to Cape Cod. The other two major medium range simulations (the Euro and Canadian) have hinted at glory, but as a whole, track this potential big system at least 100 miles east of Cape Cod and would thus mean lower snowfall totals. This clearly has the potential of being one of those season-defining best snows of the year, but to fulfill some of those American GFS fantasies, the storm will actually need to deepen much more efficiently than what is indicated by the Canadian and Euro model packages. Each scenario is different, some storms we would prefer to stay flat with minimal deepening. In this instance however, a mature system will effectively hug the Atlantic Coastline and throw mammoth amounts of moisture across interior New England. All we can do at this point is just hope.

Looking farther into the future, there is a blast of cold that should impact the region in the wake of any snow early next week. The cold shouldn't exceed anything we haven't seen already this year and should moderate by the middle of the week. Another weather system is then expected to approach the region later in the week with more potential snow just prior to the weekend of the 15th and 16th. President's week lies beyond the 16th and their are signs of a tightening of the jet in the Pacific. The result should mean a moderation in temperatures although at this time there are no glaring signs of a major New England thaw. The AO appears to be slightly negative with a neutral NAO and a strongly negative PNA and thus our "favorability" index is negative.