Think Snow, Tweet Snow !!!

Saturday, February 28, 2009

Storm is nothing spectacular but good enough for a powder day Monday or Tuesday

And about the best thing that can happen when a 6-foot base is topped with 2 inches of crust is the addition of more powder. We will have to wait until Monday for such medicine but it looks like it will arrive and be quite welcome to the March Madness crowd. This storm in many ways is a classic late-winter early-spring type of event. It also is like the lawn mower that woudn't start on the first try. The upper level energy has been slow to position itself as the storms catylist. A low pressure center will actually try and form Saturday evening along the Carolina coast but will never take flight (No pun intended at the Wright Brothers who actually did take flight on the Carolina coast). Instead, a slow moving and moist storm system currently churning away in the deep south will inhale this infusion of jet energy and produce some big time snow across the southern Appalachians and perhaps as far south as Atlanta. The storm will then gather some strength offshore and head north-northeast.

Even as we get into the late innings of forecasting this sucker, some critical items concerning the storms intensity and track remain uncertain. We do have some model agreement that the storm will track just off the east coast and pass just east of Cape Cod. In addition, models seem to agree that the storm, although strong enough to produce a widespread accumulating snow, will never deepen to sub-1000 mb and will thus fall short of the extroadinary. None of this is completely etched in stone however and a stronger storm or one that tracks a bit closer to the Atlantic Coast could change the outcome.

Storm Details
As it stands now, snow will arrive Monday morning and continue at a light to moderate rate through the evening. Even if the storm fails to attain "super" strength it remains flanked by a strong area of high pressure and the gradient will be enough to produce a blustery north wind throughout the afternoon as temperatures hold steady in the teens. Snow accumulations will be within a few inches of "6" I am guessing. Tuesday is the best bet for the powder day although Monday could finish very strong depending on when the snow begins.

First Week in March
Blustery and cold conditions will be with us through Tuesday and the sub-freezing cold will continue through the day Wednesday although the wind should subside a bit. Thursday's temps which a few days ago looked "balmy" now appear to be seasonable with readings maybe approaching the freezing mark as another west to east moving system approaches. By this point much of the country will see a move toward milder temperatures but the NAO will make another big push into negative territory and this will prevent spring-like warmth from making the full intrusion into Vermont. Instead it looks as if the region is on the fence and could see a variety of winter weather or a snow event some time around Friday of next week.

Long Range
The remainder of the first half of March is indicated to have a similar theme as the one discussed in the above paragraph. The warmth in the plains may become more exaggerated and above normal temperatures are likely across a big part of the center third of the nation. Most of the unsettled weather, meanwhile, will be focused on the west. Some of the warmth will make a few tries at reaching Vermont and may occasionally get there but should get beat back by seasonable temps and a few of the smaller type winter weather events.

Wednesday, February 25, 2009

Car wash Friday, but more new snow is on the horizon along with an improved long range outlook

Temperatures will rise above the freezing mark for the first time in a week but we should avoid most of the precipitation Thursday with the exception of a little snow in the morning and perhaps a blanket of thick fog in the afternoon. Friday will be unavoidable I am sorry to say. Temperatures will climb into the 40's supported by a stiff southerly wind and the rain will arrive sometime during the midday hours. We could see a few hours of rather heavy rain but it will all be over quick enough late in the evening with precipitation ending as a bit of snow prior to Saturday morning's first tracks.

Split flow phasing and some big storm potential
Things then get rather complicated and a bit interesting as the weather pattern throws us a bit of a curveball. It really did look as if, with all teleconnections moving into the unfavorable category, that a stretch of mild weather and lack of snow could sustain for a week if not more. This no longer appears to be the case; instead the jet will remain split and will phase early next week causing a serious jet amplification and a major east coast storm. There are timing, phasing, tracking and intensity questions and the possibilities remain a bit vast. The ingredients, amazingly, are there for the taking. There is a southern branch storm, a feature left behind by Friday's rain event and a northern jet upper air kicker, the kind that can start a fire without lighter fluid. The cold air's hold on Vermont will remain a bit tenuous and the storm will need to track close enough to MRG to bring its moisture but not too close as to erode the cold. Phasing of a storm such as this can also be a very delicate process and small changes in the timing of seemingly inconsequential weather parameters can make a big difference. The event could bring precipitation, ideally snow, to MRG Sunday and provide a big time powder day Monday. Be prepared for some changes as the uncertainty barometer remains quite high.

A longer range which looks much improved
The possibility of new snow for early next week was actually discussed in the previous post but I had given a rather gloomy outlook when discussing the end of the first full week in March. This forecast now appears much improved for you winter weather enthusiasts. The NAO, which has turned positive, will not stay so for long. Within a week it will be negative again supported by the return of the same feature which ruled the throne for the the last half of February. The longer range ensembles have adjusted somewhat and have kept most of the mild weather in the plains and have suggested a more wintry scenario including more new snow for MRG between the 4th and 8th of March. This is a striking turnabout but a welcomed one for those of us that would like to see the deep bases preserved for few more weeks before the warmth of spring emerges. With the specifics remaining so clouded 4 days from now it would be silly for me to spell out details later next week but 1 or 2 powder days is very realistic.

Tuesday, February 24, 2009

MRG can bask in victory for a few days but more turbulent pattern is ahead

Thanks to everyone for the compliments over the past few days (encouraged of course by Eric at MRG) . The weather gods have been a bit kinder to me this year than they were in 2008 but errors have still been made and Sunday's storm actually came together a bit slower than expected and thus accumulations were a bit less than expected with more snowfall in Maine than in Vermont. So we settled for the 50-60 inches in 5 days and a few days remain to enjoy the fruits of our good fortune because New England weather can giveth and can taketh away and can do so both quickly and efficiently.

Snowmelt over the next two weeks will actually occur slowly and much of the base will get retained well into March. But starting this week we will have to fight off the adverse effects of teleconnections which have now turned against us, in some cases decisively so. Blustery conditions will continue Tuesday into Tuesday night and it will remain chilly. Wednesday however will be be sunny and calm and that will make it feel substantially warmer. Wednesday will also be the last full day where snow conditions stay on the powdery side. Thursday will be a good day to ski but the snow will soften as temperatures eclipse the freezing mark under a mix of warm late-February sun and some increasing clouds.

The pattern has now evolved into one where the active weather is situated in the Pacific Northwest. With the trough situated in western North America and the protection of the negative NAO now gone we will have to deal with ice and rain perhaps on multiple occasions. There are a few individual skirmishes where we can score a victory but it is not likely to come late Thursday into Friday. This is a storm which will barrel into the Great Lakes from the central Rockies and proceed northeastward deep into Ontario and Quebec. Cold weather, and plenty of it will be situated on the western side of this storm and the cold across New England will erode very quickly Thursday night. Precipitation may begin as some sleet or freezing rain but will eventually turn to plain rain Friday as temperatures climb toward the 40's. Colder weather and a minimal amount of snow will displace the mild weather and rain for the weekend but big accumulations should not be expected.

Early part of next week has promise but negative turning PNA spells trouble
The first week in March will be a turbulent one and will live up to the traditions established by many other terbulent New England March's of years past. The period Sunday through Wednesday will be wintry as the return to colder weather this upcoming weekend will get reenforced early next week by a temporary re-positioning of the ridge/trough set up in North America. In March, you can open a small window of opportunity for winter weather and can get some big powder. So yes, an east coast storm is possible and has been indicated in a few of the cycle of recent model runs but is far from a certainty and is still more on the unlikely side. At the very least we should see snow from a "clipper" or a "mauler", or "bomber" and this will provide at least one powder day. The later part of next week however is likely to see a re-emergence of warmer temperatures and perhaps another rain event. This again being the result of the adverse teleconnections; in this case, a PNA which will turn very negative by March 4th or 6th and stay that way for a period of at least 5 days.

Saturday, February 21, 2009

Mauler set to slam MRG with upwards of 2 feet of snow - "Epicality" alert set to high !!!

And for your all English teachers, the Single Chair Weather Blog wishes not to re-invent the English language but to instead make a positive contribution. I have already emailed the good people of Merriam-Websters dictionary and have informed them that the "Epicality index" is used in the extreme instances where MRG manages to get 40 inches of snow in half a week's time. Its just another teleconnection index !!!

Mauler gone wild
Referencing a post from around February 10th, the upcoming event Sunday would be storm #3. This is the "Manitoba Mauler" which has already made quite a dent in an already amplified jet stream. And this one like so many of the other big snow makers this year was indicated, for a time, to take a track where the big impacts would be felt by our southern neighbors. We are now just a day away and suddenly the expectations have shifted and the northern half of the Green Mountain spine is situated in a strategically perfect area for another big powder-fest. This is a storm that is already doing quite a lot of snowing with very little moisture and this is a demonstration of its dynamic prowess. When this storm interacts with the warmer Atlantic Ocean waters, it will deepens very rapidly and its moist conveyor will expand. Most importantly, the storm will take on a negative tilt and the process of doing so involves establishing a pivot point which in this case will be near the small strip of coastal New Hampshire. The area 100-200 miles northwest of this pivot point stands to get some V.I.P. treatment since it will dramatically extend the period of heavy snow.

Some timing and accumulation details
The details are as follows. Snow on Sunday will begin just prior to first tracks time and for a few hours will fall at a lighter intensity. An early guess is that the mountain only gets an inch or two by noon but the action picks up in the afternoon and it will clearly be one of those days where the last run of the day will be the most powdery. By evening I expect it to be dumping and with cold temperatures up and down the middle and lower troposphere, accumulations will be quite efficient and snowfall rates could be up around 3 inches per hour. By morning snowfall rates might slacken somewhat but not until after an impressive overnight accumulation of well over a foot. Some additional terrain induced snow Monday could bring totals close to 2 feet depending on the density/fluff factor. It will be a blustery and chilly day Monday with temperatures in the teens but you can not afford to miss this day after all the ongoings of the past week.

Save the bad news for last
The cold weather will persist through Wednesday morning but concern is rapidly increasing for a big ice to rain event late in the week. This event may not be the last in what appears to be a rather adverse week of weather beginning around February 26th. This is the result of all three teleconnection indices turning unfavorable thanks to the break down of the negative NAO. That is why I would take while the taken's good on Monday because we may have to wait until well into March to see another round of weather even half as comparable

Thursday, February 19, 2009

Storm has hardly been a thing of beauty

And the snow has fallen in fits and starts and has hardly been continuous. Still we will have the powder to ski in Thursday morning as promised although temperatures through the early afternoon will be close to the freezing mark at the base and some of the snow may turn wet for a time. The middle and upper troposphere will cool as the day progresses and this will cause critical layers of the atmosphere to destabilize and set the stage for roughly 36 hours of terrain induced snow. Colder temperatures and the convective nature of the precipitation will ensure a fluffy nature to the snow and will help boost snow totals. There is no huge reason to change the 1-2 foot expectations by Saturday morning but I am not particularly impressed with the initial conveyor of moisture and this may hurt our chances of exceeding the upper range but such is life (put a gun to my head right now and my total would be 10-20).

There is more welcomed news regarding our Manitoba Mauler. Its forecasted track has shifted north and although its interaction with the Atlantic Ocean might be more limited than previously thought, it is still supported by a potent disturbance which will have a more direct impact on interior New England. Most importantly for you weekend warriors is that the new snowfall may commence Saturday evening and continue through Sunday morning. The result will be several new inches of snow for Sunday the 22nd. So yes, the idea of 4 consecutive powder days is realistic.

4-6 inches for Thursday morning
4-8 inches Friday morning
2-4 inches Saturday morning
4-8 Sunday morning from the "Mauler"

More on the long range in a day or two but for now enjoy the powder !

Tuesday, February 17, 2009

Storm won't be a home run ball but rather a double, a few well timed singles and a suicide squeeze

And those kind of rallies in baseball are good for several runs or in MRG speak a few powder days. Valentines Day 2007 it will not be since the storm is tracking too far north and too far inland for that type of event. The track of the low pressure center will pass over lower Michigan, proceed east-northeast and into the St Lawrence Valley before translating some energy to the Atlantic coast just in the nick of time. I say "nick of time" since the warm air's attempts to reach MRG will get thwarted and precipitation will remain as snow. What I like most about this event however is the terrain enhancement potential or terrain induced snow. Those words have eluded this blog far too much this winter but the pool of instability associated with this very deep and dynamic storm center will allow for an extended period of this typically very fluffy, ski friendly snow.

1-2 feet with the first inches being dense and the last being fluff
Snow from this long-talked about storm will begin Wednesday evening in between 5 and 9 PM. There has been some disagreement concerning at which time the snow will be heaviest. There is some loose agreement as of Tuesday afternoon to place the heaviest snow in this initial period during the early morning hours Thursday just prior to first tracks time. This will ensure a healthy accumulation of 5-10 inches for you Thursday skiers. Since this storm is passing so close to the mountain, there will be an area of sinking motion that could potentially end the snowfall for a time Thursday or at least reduce the intensity for a while. Such areas of sinking motion tend to transition through in time and this will be no exception. The pool of instability mentioned in the opening paragraph will create the welcomed situation where snow showers congregate around the mountain and this should begin late in the day Thursday and persist through much of the day Friday and into early Saturday. So on top of the relatively dense 6-12 inches of powder that falls prior to Thursday morning, we can expect an additional 4-8 of snow Thursday night into Friday and an additional 2-4 inches by Saturday morning. Terrain induced snow means that prognostications are subject to big errors in snow totals but the math adds up to a range of 1 to 2 feet and I will stick to that as a guess for now.

The "Manitoba Mauler"
Accumulating snow showers may taper to flurries Saturday for a period but by then we will have our eyes on another potent disturbance. This is the Manitoba Mauler discussed in the previous post and it will dive south from its appropriately named source region late on Saturday. The east coast can be described as a "tinder box" as the storm reaches the Atlantic Coast since the amplified trough will by then be well established and will set the foreground for a rapidly intensifying noreaster on Sunday. The timing, strength, track and eventual impact are all a question mark; in fact, there is a good chance that the impact on central and northern Vermont is limited but its a storm worth watching and its potential will get lots of color from the news media since an impact on major metro's is a possibility. The timing on such an event is most likely to be Monday as of now but stay tuned. We can say for certain that it will be blustery and chilly along with those flurries on Saturday and the cold weather will persist through early next week before giving way to a few mild days in the middle to later part of the week.

Sunday, February 15, 2009

Track of late week storm continues to trend north

This trend has been a consistent one for a few days now and a storm that looked at one point to be taking aim at the Virginia Tidewater is now taking aim at MRG. The ideal winter storms do not track right at MRG as some of you know and we would prefer they track toward Boston leaving the spine of Green Mountains safely on the snowy flank. This storm still has a few days to make up its mind but a track toward MRG would limit the upside potential for powder and would mean a snowfall range of 12-18 as opposed to 18-36. If the storm tracks further south then our snowfall potential would again rise. Such a result may seem unlikely considering the trend but with a high latitude block fighting on our behalf we could certainly see expectations change in our favor at the last second.

Storm and all its details
In the meantime all will stay quiet. Flurries Monday will not amount to much and Tuesday should feature plenty of sunshine which will accompany this latest round of chilly temperatures. It will not be until Wednesday when clouds and eventually snowfall arrives from an already intense approaching storm system. If the storm tracks according to current expectations, it will deepen to 990 mb by the time it cruises through southern Michigan late Wednesday. It will continue to strengthen as it tracks toward Vermont and snow will overspread MRG late Wednesday. Snow will become very intense Wednesday night as the storm efficiently makes use of the available moisture from the warmer Atlantic Ocean waters. Because the low pressure center is tracking so close to the mountain, there are some inherent concerns. 1) Any storm passing this close is likely to bring a dry slot which will mean a period Thursday when no precipitation is falling or falling very lightly. 2) A storm passing this close can bring mid level warmth, that if strong enough, can cause a change to sleet or freezing rain. I am not overly concerned about the latter and the former isn't really that big of a deal. Snow will be heavy enough Wednesday night to accumulate 8-12 inches by first tracks time Thursday and a dry slot might at least make travel a bit safer and easier even if it does mean less powder. The pool of instability which will move over the mountain in the wake of the passage of this powerful system looks impressive. It will be enough, I think, to cause significant terrain induced snow beginning later Thursday and persisting into Friday. The three day snow total ending Friday may surpass 20 as a result but that should be a best case scenario only at this point.

Yes there is still another system to watch
There is then the question of the next system which will impact portions of the east coast between Sunday the 22nd and Tuesday the 24th. This is a system that will be spawned by a vigorous piece of jet energy diving southeast out of Canada. This is the "Manitoba Mauler" and may prove to be a memorable one for some location along the east coast but the question is where. The storm will ensure that the upper trough along the east coast is reinforced and it is possible that the system and its energy will be too far south to mean additional snows at MRG or we could again see a northward trend, another sequel to a movie that has repeated itself more than a few times this winter.

Milder weather very late in the month
The last item of note relates to the long range. After the round of chilly weather beginning on the 21st and ending around the 25th there are new signs of a stretch of milder temperatures. A few days ago it looked as though the negative NAO would hold through the balance of the month and would ultimately cause a big stretch of cold and sometimes powdery weather for us on the mountain. It now looks like the blocking negative NAO will break down somewhat and be replaced by a trough west/ridge east scenario that could then lead to an late February thaw. It would be very late in February though with no threat of extreme warmth or any rain until the 25th of the month at least.

Thursday, February 12, 2009

February 19th has everyone's attention

And it seems like even the most casual followers of the blog have been sending me a few cents about next week and what could be. Thanks to Art Hendrix who was nice enough to comment about the present and a few inches of snow which has fallen at MRG on the backside of what turned into a mostly rain event. These few inches will help as will some colder weather. Storm #1 however will not provide any assistance. This is a system that will be a victim of this monstrocity of a blocking pattern and as it spreads precipitation across the midwest and takes aim at the northeast, it will get forced southward taking much of its energy and moisture with it. A negative NAO such as this with blocking such as this can have some very positive uses as well and as predicted we will earn our dividends with a little patience.

Our Feb 19th "hypothetical storm" will have some tranquility in the foreground. Flurries and snow showers on Friday and Saturday will amount to a light and very fluffy accumulation but I think the depth of instability is not deep enough for a big terrain induced accumulation. These flurries may continue off and on with some intermittent sunshine both on Sunday and Monday. We will also see a brisk wind with temperatures in the 20's during the days and 5-10 at night. Tuesday may be a bit colder but with less wind.

Feb 19th - The ingredients that make a storm
As the cold weather stabilizes over interior New England the forces of mother nature will conspire and do so very early in the ball game. Pacific energy from the rockies will combine forces with jet energy diving south from Alberta. This combination will occur in the plains and thus the intensification of this storm system will occur early and cause heavy snow and rain across the Midwest. This storm has a lot of people talking as a result since major metropolitan areas from the Midwest to the Northeast has the potential to see an impact. Sponsors that were nice enough to support The Weather Channel are licking their chops as big ratings are sure to come.

Us skiers have other thoughts however like images of this --> http://wintercenter.homestead.com/photo1969b.html

For those old enough to remember, the 100 hour New England snowstorm of late February 1969 was a skiers paradise with upwards of 6 feet of snow in parts of the Northeast Kingdom or at least according to the folklore. It came on the heels of the famous Lindsay snowstorm which got its name from the NYC politician it claimed (not literally but politically if you get my meaning).

No time for a history lesson however since we need to lay out what we know. The storm will already be quite a force as it approaches late on Wednesday. As this already well established low pressure center interacts with the forces of the Atlantic Ocean, the intensification will continue and blizzard-like conditions are very possible over portions of New England Thursday and into Friday. Heavy snow across interior New England and the spine of the Green Mountains to be specific and MRG to be more specific seems to be a predictable by-product but lets not give this storm an early KISS OF DEATH. Thursday and Friday could be Valentine's day 2007 re-incarnated or it could be something less or it could be not at all.

In all honesty and with all the kidding aside, the storm next week is probably going to be a bit more than "not at all". Its just a matter of details and those still need to be ironed out and we will do so in the coming days. There is another storm also in its wake that will need a an injection of clarity. This storm may is showing up a bit later than it did a few days ago but February 19th is hogging a lot of press and its impact may span more days than just Feb 19.

Enjoy the presidents day holiday fellow MRGers and updates will continue to flow !!

Tuesday, February 10, 2009

Rain makes it to MRG but changes to snow Friday; big east coast storm possible Feb 18

Too much mild air has made it deep into New England and we are not getting the help we need from the track of the storm on Thursday. It is a moist storm system which will track right over interior New England, normally not all that terrible but without any available cold we should prepare ourselves for rain. Some drizzle or freezing drizzle will commence as early as Wednesday morning and temperatures will climb above freezing as heavier precipitation arrives during the evening. About a half an inch of rain can be expected Wednesday night into early Thursday followed by a break in the precipitation while the atmosphere slowly cools from top to bottom. Finally, some snow will begin later Thursday which should continue into Friday thanks to the benefits of terrain enhancement. Terrain induced snow has been held to a minimum this year and the case can be made that the unstable layer of the lower atmosphere will not be enough to support a big accumulation but 2-4 inches by early Friday is a reasonable expectation all of which will be very much needed after the rain.

We have been waiting for February 12th in order to obtain more activity in the pattern and activity we will get. We will still have the benefit of the block stretching from eastern Canada to Greenland and this will ensure a winter-like regime. This and a relatively consolidated and active west to east jet stream will give us a few chances at storms. There are three in total worthy of mention and the question with all three is whether or not moisture can reach MRG's latitude. If the president's week part of the calendar is defined by the period beginning Friday the 13th and ending Sunday the 22nd then my prediction would be for 3 powder days and no rain. We will likely however miss 2 of the three storms mentioned and catch at least the healthy northern edge of one storm system.

Storm #1
Will start as a relatively disorganized area of moisture, much of which will stay well south of New England. By the weekend, low pressure will try and organize and move up the Ohio Valley and allow moisture in the Mid-Atlantic to make a northward push into New England. This system may not be strong enough and the precipitation shield may not be large enough for snow to make it deep into Vermont but we have seen this movie before and to say MRG has no chance for snowfall is both overly presumptuous and silly.

Storm # 2
Is a very interesting system which will carry with it a well developed area of low pressure even as it crosses into the Mississippi Valley around the time of Tuesday February 17th. This will mean big snow for a big part of the Midwest, an area of the country more accustomed to snowfall of much smaller amounts. As the storm moves into the Mid-Atlantic it will interact with the Atlantic Ocean and deepen rather quickly. A garden variety system with this storm track might fail to bring moisture into interior New England but this storm might do a bit better than garden variety. Since the weather system has such potential the range of outcomes stretches from dry weather to 20-plus inches of snow.

Storm # 3
Would arrive on the east coast just prior to or during the weekend of the 21st-22nd. It is a bit early to even characterize this one but it is another chance in a period where we will gladly accept as many chances as possible

In the event that we miss storm #3 or any of the other systems we can be assured of a continuous period of below freezing temperatures although nothing extreme. As I mentioned in the last post, the negative NAO is so strong that it will in effect block extreme arctic air from getting involved in the pattern. I don't think president's week skiers will complain but we will need the snowfall and all of it at least for now remains a question mark.

Saturday, February 7, 2009

Mild weather clashes with negative NAO and makes for a tough call for Feb 12

This is a date we have been singling-out for a few posts as a time in which the pattern will turn active. By the looks of things this appears to be a good prognostication but the specifics regarding the storm on February 12th remained veiled in a cloud of fog and all we can do is lay out a few possibilities and wait a day or two. Until then we can expect temperatures to take a few very sharp up and down turns. It will start when the mild weather gives way to snow showers and a gusty and chilly wind on Sunday. The ski day Sunday could very well start with a little corn and end with a little powder if we are lucky enough to get a heavy snow shower or two during the middle part of the day.

February 12th and the varying scenarios
Temperatures will remain chilly Sunday night, Monday and Monday night but will make a quick recovery Tuesday as readings by then approach the freezing mark. Wednesday could the turn out quite balmy with temperatures reaching the 40's on mild southwesterly breezes. We have made mention of the most dominant feature on the North American weather map - a block in the jet stream which encompasses the vast area from eastern Canada through the Davis straights and into Greenland. This block represents an expansive area of unseasonably warm and stable weather in that part of the world but it also has significant ramifications on our part of the world. It is a feature partly to blame for the mild weather but west to east moving weather systems will have a tough time penetrating this feature with any success and they are thus forced to take "the Holland Tunnel" and dive underneath. Such will be the case with the February 12th case or at least I think. The actual specific track remains important and is still very much up in the air. The amount of available cold is also very important this too remains a question since only a limited amount will be present upon the storms arrival on Thursday. A few days ago I made a guess that the storm may produce some rain then some wet snow and then powder snow and our trusted friend the European model is suggesting such a scenario or something close to that anyway. Guidance from other models have varied from run to run but have been somewhat more pessimistic including more warmth and more rain.

President's Day and the week that follows
February 12th will mark a temporary end to the mild weather. The cold that follows will be far from severe as the above mentioned block will actually act as an arctic blockade. The mostly Canadian air that will cover the region should ensure that precipitation through February 21st stays in the form of snow. The track of storms in this period could be rather suppressed since weather systems will be forced to go farther and farther underneath the large jet stream blocking feature. Since there will be multiple systems crossing the country between the 14th and 21st of February it is reasonable to expect a fruitful outcome from one of them at least either during the President's day weekend or the week that follows. We have gotten some late inning drama from a few storms this year and perhaps Presidents week will provide an opportunity for more.

Wednesday, February 4, 2009

Cold air to relent this weekend but no big snows or rains until around the time of Feb 12

Vermont is back in the grip of some reasonably strong chill although as the saying goes "its all relative". Cold air has graced us with its presence in a much more intense form already this winter so I would say we have acclimatized. Still temperatures will plummet to -10 Thursday morning and struggle into the single numbers during the day making Thursday the coldest of the week. Snowfall will be limited to flurries throughout the week as it appears the lowest unstable layer of the atmosphere will be too shallow to support terrain induced snows of any magnitude.

Temperatures will make a nice recovery this weekend, possibly touching the 30-degree mark Saturday and into the 30's Sunday. Aside from the flurries, we won't get any new snow on Saturday and we will have to settle for the higher-angled February sun which should be prevalent throughout much of the day. Temperatures will hover near the freezing mark Saturday night into early Sunday thanks to the first of two pushes of milder temperatures. A weak weather system will pass to the north and may bring some light snow Saturday night that could even evolve into a light rain at low elevations Sunday morning. A light snow accumulation is possible by first tracks time Sunday but the snow could also be wet in nature and the milder day time readings during the day Sunday could further soften the base.

Negative NAO must save our snow next week
The prevailing overall pattern for the weekend into the early next week consists of a negative NAO of considerable strength but with most of the mid-latitude jet stream energy in the west. This allows for the push of milder temperatures over the weekend which will be followed by a return to colder readings Monday and Monday night followed again my a second push of milder temperatures Tuesday or Wednesday. This second push of mild air precedes a more interesting weather situation as a sizable weather system may cross the country. The fear of course is that it will reach interior New England as the relative warmth peaks and the result will thus be rain. This is a valid concern but as I mentioned in previous posts we can lean heavily on the negative NAO in such circumstances and the blocking could very well act as an important ally. The possibilities include a great variety of outcomes but if I can make a preliminary guess then I would venture to say that some rain to heavy snow type of event is very possible and quite possibly the most possible of all outcomes.

President's Day weekend looks active at an early glance
I will also stick with the notion that the date of February 12th will mark the start of more active weather which should continue into the weekend of the 14th and 15th. This would mean a second or follow-up storm within a day or two of February 15th. President's day skiing thus as a lot of potential and a very early look at President's week appears to have promise but it is a long way off.

Monday, February 2, 2009

Tuesday storm too far east and some milder temps may follow this week's chill

And by not updating the blog when i should have been I have avoided some of the back and forth drama with this weather system. This is a storm which will start as a disorganized area of precipitation in the southeast and then get a big kick in the pants as strong upper level energy from Manitoba injects itself into the playing field. The storm will grow rapidly into a classic noreaster but its track is too far east for a major Vermont impact and snow from the storm will be limited to areas such as Cape Cod if even that. Temperatures have warmed above the freezing mark on Sunday for the first time in over a month and will make a gradual descent Monday followed by a rapid decent back into frigid territory on Tuesday. I don't expect the light snow or flurries to amount to much Monday or Tuesday and temperatures will fall through the teens on Tuesday. Wednesday and Thursday will be bone chilling with temperatures in the single numbers through much of the day and well below zero at night. Wind chill temps late Tuesday into Wednesday will be even lower.

Mild air makes a push at us this weekend into next week but hopefully without the rain
A strong negative NAO has established itself and will act as the regions "insurance policy" through the first half of February. I put it this way because underneath the blocking across the Davis Straits and Greenland will be a changeable jet stream. One capable of producing a big storm last week followed by milder weather Superbowl Sunday into Monday and then much colder weather for the balance of the week. The colder weather is of course the result of a big trough amplification but this regime will not get any reinforcement and a series of Pacific impulses will again put the center of attention on the west for powder beginning this weekend while the east sees another push of milder temperatures. I have faith in downstream northern latitude blocking and the negative NAO and I continue to think that it will prove instrumental in avoiding any big time rain events even if the weather turns mild for a few days between the 6th-10th of the month. Systems with any real moisture will be shunted southward and be forced under the blocking to the north. I can see temperatures reaching the 40's for as many as 2 days in this stretch up through the 10th and there may be a little rain but I don't a base killing Christmas debacle part II. In terms of snowfall, we actually may get a few inches in front of the milder push of air going into the weekend. Models are then hinting at a more organized system early next week (Feb 9th) which will require help from the NAO to produce as I mentioned.

In to middle February
As the blocking continues to hold its ground after the 10th I would expect the situation to get more exciting. Long range ensembles can only assess the situation loosely but there are indications that energy from the Pacific will pass through the Rockies and across the country more fluidly. This will mean another period of more active weather beginning around the 11th or 12th of the month. We have not had the benefit of much of a southern branch this year and have relied on a consolidated but not overbearing Pacific jet which has sent a few healthy snow producers across the country and into New England. The snowfall contrast from north to south because of this lacking southern branch is dramatic but we are not complaining nor should we be surprised. The lack of a southern branch of the jet is tied closely to the lack of an El Nino which has helped allow the cold to be more dominant this year. The lack of rain/ice over the last month can be attibuted to the weaker La Nina. This may have helped produce a drier month of January but after the storm last week I will happily trade less precipitation and give up the ice and rain.