The ground is white, the trees are white thanks to the warm and wet weather that preceded our light snowfall and at least it looks a bit wintry out there. It will also stay wintry for the next few days with some single digit overnights and daytime temps in the 20's. The weather itself will remain dry through Christmas Day but a clipper system will bring its clouds to the region late Sunday and snow showers Sunday night into Monday. This clipper system is potent enough to temporarily carve a nice little trough along the northeast coast and there are some indications that instability as a result of this will allow for snow showers through much of Monday, enough for a terrain induced accumulation of a few inches.
The weather evolution next week appears a bit different than it has the last few days. Most of the changes are less than desirable, but Tuesday could be an interesting event although it if lives up to the tradition of December 2011 it will simply be another rain event. The changes involve southern branch Gulf of Mexico moisture and energy that will be grabbed by the collar by a faster moving clipper system. The result will be a significant precipitation producing weather system for the entire northeast beginning later Tuesday and none of this appeared likely even 36 hours ago. The cold which is expected to persist through Tuesday morning will erode very quickly and a fresh supply of cold will far removed from the weather picture. The southern energy however allows the storm to take a more southern track so temperatures should be close to freezing when the precipitation begins Tuesday evening. What appears most likely is period of both rain and snow, with precipitation beginning as a mixture before changing to rain then perhaps back to a heavy snow before ending midday Wednesday. With any weather system of this nature though, slight changes in the forecast variables could push the result in either direction. We could certainly use a surprise heavy snow. It is possible, if it does happen it could be of the "sierra cement" variety but us skiers know how desperately the Vermont high country needs a boost to the snowpack right now.
The less than desirable part of the forecast change will take place around New Years Day where it appears models are converging on yet another warm-up for the east coast. The mild push would begin Friday after semi-seasonable temperatures late Wednesday into Thursday. How fast this occurs remains uncertain but much above normal temperatures are now very likely in the New Years Eve to New Years Day time frame and with that will come the increased risk for more rain.
Beyond the first looks slightly more promising. Much will depend on the ability to break down the jet stream ridge in the central mid-latitude Pacific. There is not a lot of evidence of this as of yet and with that we will continue to struggle. That being said both ensembles indicate a ridge west/trough east jet stream configuration and such an outcome would still be better verses what the previous month has wrought.
Friday, December 23, 2011
Wednesday, December 21, 2011
Hoping we go one for two this weekend
Snow is at least part of the discussion this go round. It will be worth thinking about in the midst of what should be a mostly rainy or freezing rainy Wednesday across the Green Mountains of Vermont. The situation sets up as follows. The mainly wet system Wednesday will exit and leave with it one extra day of above freezing temperatures Thursday. The front associated with Wednesday's system is a very weak one initially but the entrainment of some polar energy will give this front some legs and invite a wave of low pressure to develop near the Gulf Coast and track very quickly northeast toward the New England coast Friday. It is less than 72 hours away and the track of impact from this storm remains unclear; in fact, the much more reliable European model is suggesting no impact at all (although the European wants to tell a whole different yet interesting story Christmas weekend, more on that later). The system however does have some potential and also has the benefit of a fresh supply of what limited cold is available from this deplorable weather pattern. The cold will drain gradually southward out of Canada as the wave of low pressure approaches Thursday night. Snow could be moderate to heavy for a time if the storm tracks close to Long Island or attains a stronger intensity than models suggest. Its quick movement however would keep snowfall totals generally in the light to moderate category if at all.
The European model, which has been eating the American Model's lunch all month is suggesting not at all. That being said, the European model maintains that storm development along the aforementioned front will be later in the forecast period. Christmas Day to be exact. The supply of cold air will be more stale but the pattern will be in the process of turning more amplified and could allow for major storm to take shape and one that could deal interior areas the bulk of the snow. The American model will have none of this however and is putting all its eggs in Friday's basket.
My best guess is that we go one for two here. If Friday's wave of low pressure fails to materialize it will leave the door open for the ignition of the second and potentially more potent wave Sunday. A stronger system and a snowier Friday could act to drive the front farther offshore by Sunday. I can't see two events in the 3-4 day stretch.
No reason to doubt any of the thinking beyond Christmas Day. The temporary amplification of the eastern trough is no match for the furious jet action in the Pacific. This is just been such a demoralizing scenario to start the ski year and there are stronger indications it will try and re-assert itself after the 27th of the month. This will mean another mild of push of air after the 27th and potentially another non-snow event before the new year. Ensembles are then suggesting the potential for temporary pushes of cold around New Years Day and beyond but it is vital we break the positive Arctic Oscillation and we have yet to see evidence of that.
The European model, which has been eating the American Model's lunch all month is suggesting not at all. That being said, the European model maintains that storm development along the aforementioned front will be later in the forecast period. Christmas Day to be exact. The supply of cold air will be more stale but the pattern will be in the process of turning more amplified and could allow for major storm to take shape and one that could deal interior areas the bulk of the snow. The American model will have none of this however and is putting all its eggs in Friday's basket.
My best guess is that we go one for two here. If Friday's wave of low pressure fails to materialize it will leave the door open for the ignition of the second and potentially more potent wave Sunday. A stronger system and a snowier Friday could act to drive the front farther offshore by Sunday. I can't see two events in the 3-4 day stretch.
No reason to doubt any of the thinking beyond Christmas Day. The temporary amplification of the eastern trough is no match for the furious jet action in the Pacific. This is just been such a demoralizing scenario to start the ski year and there are stronger indications it will try and re-assert itself after the 27th of the month. This will mean another mild of push of air after the 27th and potentially another non-snow event before the new year. Ensembles are then suggesting the potential for temporary pushes of cold around New Years Day and beyond but it is vital we break the positive Arctic Oscillation and we have yet to see evidence of that.
Saturday, December 17, 2011
Change we can believe in ?? Not quite
We have made it to "the reprieve". The warm weather has finally given way to more seasonable temperatures but it remains extremely difficult to get excited about the outlook going forward. In short, the pattern continues to be plagued by many of the same problems discussed in the blog in previous entries. The repetition of these features, particularly in the Pacific is making me feel like a boxer against the ropes getting his head beat in as he tries to avoid a knock down. The next 10 or so days should be better verses what we have seen so far this December but I want "change I can believe in" to borrow the Obama slogan and I have yet to see it.
We finally have our hands on some arctic cold which is a start. As we move into Monday the cold will get re-enforced as a clipper system moves through the eastern Great Lakes and spreads what should be a light accumulation of snow to the region late Monday the 19th. This is not the system we have been watching however, that system will begin its journey in the southern Rockies, move into the Red River Valley later Monday and track across the rest of the country Tuesday. We should see precipitation from this feature either late Tuesday into Wednesday but although the track of this system is not nearly as unfavorable as previous, our supply of cold air will quickly become stale and will struggle to hold its ground. At best we can expect a wet snow out of this but it is possible for a changeover to mixed precipitation, freezing rain or even a period of rain. Everything should be over and done with by Wednesday evening and a gradual return to colder conditions.
The return to chill late in the week should be the start of another stretch of at least seasonable temperatures and possibly even below normal temperatures for a day or two. The return to chill late in the week might also include some type of mixed precipitation to snow event. This would likely take the form of a wave of low pressure energizing a slow moving cold front. This however along with the cold weather that follows should preserve the period between the 24th and 28th of the month which i know is a big one for vacation planners. During this period, there is no evidence of a major snow event but clipper systems and weaker features could certainly provide some fresh powder to the region Christmas Day or the two days that follow.
The brief amplification of a western North American upper ridge will play its hand in that aforementioned 24th-28th period but there continues to be a lack of evidence that this change will be of a permanent. Instead, the broader weather map reverts back to the features that have hurt us. Height rises and upper ridging in the Mid-latitude Pacific coupled with the potential redevelopment of an poler vortex over Alaska. These are the main ingredients to the zonal flow scenario we have seen now for 5 weeks. The Arctic Oscillation and North Atlantic Oscillation continue to run positive revealing the lack of blocking at high latitudes and it is only the PNA providing some support over the next 10 days that is providing any real aid.
We finally have our hands on some arctic cold which is a start. As we move into Monday the cold will get re-enforced as a clipper system moves through the eastern Great Lakes and spreads what should be a light accumulation of snow to the region late Monday the 19th. This is not the system we have been watching however, that system will begin its journey in the southern Rockies, move into the Red River Valley later Monday and track across the rest of the country Tuesday. We should see precipitation from this feature either late Tuesday into Wednesday but although the track of this system is not nearly as unfavorable as previous, our supply of cold air will quickly become stale and will struggle to hold its ground. At best we can expect a wet snow out of this but it is possible for a changeover to mixed precipitation, freezing rain or even a period of rain. Everything should be over and done with by Wednesday evening and a gradual return to colder conditions.
The return to chill late in the week should be the start of another stretch of at least seasonable temperatures and possibly even below normal temperatures for a day or two. The return to chill late in the week might also include some type of mixed precipitation to snow event. This would likely take the form of a wave of low pressure energizing a slow moving cold front. This however along with the cold weather that follows should preserve the period between the 24th and 28th of the month which i know is a big one for vacation planners. During this period, there is no evidence of a major snow event but clipper systems and weaker features could certainly provide some fresh powder to the region Christmas Day or the two days that follow.
The brief amplification of a western North American upper ridge will play its hand in that aforementioned 24th-28th period but there continues to be a lack of evidence that this change will be of a permanent. Instead, the broader weather map reverts back to the features that have hurt us. Height rises and upper ridging in the Mid-latitude Pacific coupled with the potential redevelopment of an poler vortex over Alaska. These are the main ingredients to the zonal flow scenario we have seen now for 5 weeks. The Arctic Oscillation and North Atlantic Oscillation continue to run positive revealing the lack of blocking at high latitudes and it is only the PNA providing some support over the next 10 days that is providing any real aid.
Tuesday, December 13, 2011
Encouraging signs in some of the Ensemble data
Yet another round of mild weather and rain is poised to invade interior New England and specifically the northern Green Mountain chain. Temperatures will soar well into the 40's Thursday and we will have to endure a period of rain during the middle of the day. The weather system responsible for the rain will bring colder weather, much colder weather in its wake. We will finally start to benefit from the 80 percent frozen Hudson Bay and colder air will thus be able to access eastern Canada more freely and more vigorously and can push southward from there. Temperatures over the weekend will stay well below freezing through the weekend and a clipper system Sunday should spread a fluffy accumulation of powder to the mountains.
Our pivotal pre-holiday moment will come early next week, likely Tuesday, as the cold air relinquishes its grip on the region and a stronger storm system approaches from the southwest. There are questions about both the track of this system and the available cold air and I am certainly concerned about both. We have as you know, no blocking mechanism to keep cold air in place and the prevailing pattern and warm Great Lakes has constantly pulled these systems farther north and farther west. It is very possible if not likely that next Tuesday sees this very result. With all that said, models are still odds and have yet to settle on a solution and are allowing for the possibility of a more wintry scenario.
Tuesday is important because if we can get some snow or even sleet out of that system, the stage will get brighter. The European Ensemble which has been accurately predicting almost tropical weather for the northeast over the past 3-4 weeks is finally showing some key changes starting in the middle of next week. It is not total vindication but the pattern will get an important boost from at least the temporary establishment of a western North American upper ridge. This should send some rather impressive shots of cold deep into the U.S. as we approach Christmas. The polar vortex in Alaska will also weaken at this point allowing the Jet in the Pacific to relax. The pattern in the Pacific is still disconcerting. It will still feature a lot of this Jet Stream level warmth referred to as ridging. Last year the Pacific was surprisingly unstable at mid-latitudes and this was attributed to the highly negative AO which dominated the weather pattern for December and January. Going a little deeper into the world of "geek speak" meteorologists talk about the formation of a high latitude "block' as a stratospheric warming event. A sudden warming of the stratosphere signals the formation of a high latitude block and thus signals that there will be a major southward transport of arctic air somewhere. The stratosphere which has been very cold so far this winter is expected to see such an event in the next 7-10 days. The phenomenon can only be viewed in general terms and does not reveal specifics. All we know is that the atmosphere will get shaken up, at least a little as we get toward the holidays. Given what has happened so far, we have little too lose from such a shake-up.
Our pivotal pre-holiday moment will come early next week, likely Tuesday, as the cold air relinquishes its grip on the region and a stronger storm system approaches from the southwest. There are questions about both the track of this system and the available cold air and I am certainly concerned about both. We have as you know, no blocking mechanism to keep cold air in place and the prevailing pattern and warm Great Lakes has constantly pulled these systems farther north and farther west. It is very possible if not likely that next Tuesday sees this very result. With all that said, models are still odds and have yet to settle on a solution and are allowing for the possibility of a more wintry scenario.
Tuesday is important because if we can get some snow or even sleet out of that system, the stage will get brighter. The European Ensemble which has been accurately predicting almost tropical weather for the northeast over the past 3-4 weeks is finally showing some key changes starting in the middle of next week. It is not total vindication but the pattern will get an important boost from at least the temporary establishment of a western North American upper ridge. This should send some rather impressive shots of cold deep into the U.S. as we approach Christmas. The polar vortex in Alaska will also weaken at this point allowing the Jet in the Pacific to relax. The pattern in the Pacific is still disconcerting. It will still feature a lot of this Jet Stream level warmth referred to as ridging. Last year the Pacific was surprisingly unstable at mid-latitudes and this was attributed to the highly negative AO which dominated the weather pattern for December and January. Going a little deeper into the world of "geek speak" meteorologists talk about the formation of a high latitude "block' as a stratospheric warming event. A sudden warming of the stratosphere signals the formation of a high latitude block and thus signals that there will be a major southward transport of arctic air somewhere. The stratosphere which has been very cold so far this winter is expected to see such an event in the next 7-10 days. The phenomenon can only be viewed in general terms and does not reveal specifics. All we know is that the atmosphere will get shaken up, at least a little as we get toward the holidays. Given what has happened so far, we have little too lose from such a shake-up.
Saturday, December 10, 2011
In search of the lost cold - extended version
In short we are continuing to get really hurt by jet stream level warmth in the mid-latitude Pacific. It continues to be one of the biggest features on the globe and it continues to haunt MRG and surrounding Vermont encouraging frequent warm-ups, rain events and an inability to build an early season snow-pack. These struggles will continue through the holidays thanks largely to the Pacific issues and the Arctic Oscillation which will remain mostly positive for the next two weeks.
The next few days will remain mostly below freezing, at least in the high country. By Thursday however, another push of mild weather will precede what appears to be a rain event. A better track might allow for a period of snow with this system but the Great Lakes aggregate continues to be warm relative to average, 7-10 degrees warmer than average in fact and that often induces low pressure centers in the center of the country to track toward the Great Lakes and thus bring milder weather ahead of the track and deep into New England. We will find some lost cold behind this system, a legitimate shot of arctic air in fact by next weekend and the coldest weather of the season so far. The Ensembles beyond this time frame however are not painting a pretty picture however. Specifically one that still includes the above-mentioned features. I would thus guess that although we may see some snow between the 17th and 19th of the month we are likely to see another warm-up prior to the holidays
The next few days will remain mostly below freezing, at least in the high country. By Thursday however, another push of mild weather will precede what appears to be a rain event. A better track might allow for a period of snow with this system but the Great Lakes aggregate continues to be warm relative to average, 7-10 degrees warmer than average in fact and that often induces low pressure centers in the center of the country to track toward the Great Lakes and thus bring milder weather ahead of the track and deep into New England. We will find some lost cold behind this system, a legitimate shot of arctic air in fact by next weekend and the coldest weather of the season so far. The Ensembles beyond this time frame however are not painting a pretty picture however. Specifically one that still includes the above-mentioned features. I would thus guess that although we may see some snow between the 17th and 19th of the month we are likely to see another warm-up prior to the holidays
Monday, December 5, 2011
Its looking better, at least a little
For one thing, we will get a reprieve from the sustained warmth which has plagued the region throughout November into the early part of this month. More generally speaking the teleconnection indices which have been quite disruptive particularly in recent weeks will also take a break There is no evidence of a decisive shift toward a "blocking" pattern of some variety, but a relatively neutral AO and slightly positive PNA will be just enough to at least get the ball rolling in the right direction. The first chance for significant snow is a very long shot. If it happens it will come from a wave of low pressure forming along the slow moving front to the regions south. If any real snow is to occur from this, the storm will need to intensify much quicker than what is currently indicated; otherwise, the storm will bring precipitation, and mainly rain to coastal cities.
A clipper system will arrive late Friday in advance of a much more substantial shot of chill, the first chance we will have of seeing temperatures lower than 10 F. A few inches of snow are possible from this before temperatures take this plunge. Thereafter, the pattern will be anchored by a classic La Nina style upper ridge in the Gulf of Alaska which is traditionally a dangerous place for such a feature. Thus, the risk remains for a early week warm up and non-snow type of event between the 12th and 14th of the month. Recent medium range model runs however have suggested that cold weather will grip a large portion of southern Canada and will keep us in the game so to speak. Any warm-up next week will likely be brief and my not occur at all. Cold weather will then overtake the region again after 15th and should grip the region for at least a 4-6 day stretch. It may not be a home-run forecast but at least an improvement over what we have seen.
Another positive development is the speed at which the Hudson Bay is freezing. Cold weather has gripped that region of Canada and that large body of water is on pace to freeze in a week to 10 days. This would be several weeks earlier than last year and will allow unmodified cold weather to move into eastern Canada a lot more freely. This is a critical thermal feedback that we will need to work in our favor if we are to proceed into the heart of this winter without any high latitude "blocking" to assist us.
A clipper system will arrive late Friday in advance of a much more substantial shot of chill, the first chance we will have of seeing temperatures lower than 10 F. A few inches of snow are possible from this before temperatures take this plunge. Thereafter, the pattern will be anchored by a classic La Nina style upper ridge in the Gulf of Alaska which is traditionally a dangerous place for such a feature. Thus, the risk remains for a early week warm up and non-snow type of event between the 12th and 14th of the month. Recent medium range model runs however have suggested that cold weather will grip a large portion of southern Canada and will keep us in the game so to speak. Any warm-up next week will likely be brief and my not occur at all. Cold weather will then overtake the region again after 15th and should grip the region for at least a 4-6 day stretch. It may not be a home-run forecast but at least an improvement over what we have seen.
Another positive development is the speed at which the Hudson Bay is freezing. Cold weather has gripped that region of Canada and that large body of water is on pace to freeze in a week to 10 days. This would be several weeks earlier than last year and will allow unmodified cold weather to move into eastern Canada a lot more freely. This is a critical thermal feedback that we will need to work in our favor if we are to proceed into the heart of this winter without any high latitude "blocking" to assist us.
Saturday, December 3, 2011
Another week of mild weather coming
A few days ago I broke down and bought "The Last Waltz" on blu-ray. This is a concert/documentary by Martin Scorsese on The Band's last performance in late 1976 at the Winterland Ballroom in San Francisco. I can't claim to be a die-hard fan of "The Band", admittedly it seemed far removed from my generation but in the end I was completely blown away. It really is an organic music experience like no other I think. The incredible collection of musicians, the assortment of musical styles and influences ranging from jazz to country/bluegrass to blues to straight up rock and the sincerity of the interviews and performances are really hard to match. Sadly it all especially rings true in an environment watered down with the likes of Katie Perry or the other mass-produced pop music filling the airwaves. Especially for those generation Y2k's looking for something "real", go out and get your hands on "The Last Waltz", its a real piece of musical Americana. The irony there is that "The Band" is Canadian and the concert includes American musicians paying tribute to their contributions to music.
I can't speak so positively about the weather at MRG over the next week. Mild air will work its way back into the region later Sunday and into Monday. With that will come the rain which will in association with a slow moving front. The rain will be off and on between Monday and Tuesday night totaling between .50 and 1 inch total. Colder weather then arrives Wednesday night with flurries and snow showers but even this cold will fail to bring temperatures back to normal and might also give way to another mild push and rain for next weekend although this remains a question mark right now.
About the only thing we do know for sure beyond a week is that we will see a more serious punch of cold weather late next weekend after another rain or mixed precipitation event next weekend. Several runs of the European Ensemble have suggested that the very positive AO will continue to rule the day allowing the cold weather next weekend/early next week to lift and opening the door for more mild temperatures and potentially more rain. The GFS and its ensembles suggest otherwise; in fact, the GFS is so dramatically different beyond the 12th of December allowing arctic cold to completely overwhelm the pattern. This evolution is supported by a developing La Nina style ridge in the Gulf of Alaska and allowing the downstream trough to become expansive enough to cover most of Canada. It defies my sense of reality but it is nonetheless encouraging. It would be realistic enough to expect cold weather to expand its influence across Canada and at least become somewhat accessible to northern New England. I would not expect cold weather to be as persistent as what the GFS suggests beyond the 12th of the month.
I can't speak so positively about the weather at MRG over the next week. Mild air will work its way back into the region later Sunday and into Monday. With that will come the rain which will in association with a slow moving front. The rain will be off and on between Monday and Tuesday night totaling between .50 and 1 inch total. Colder weather then arrives Wednesday night with flurries and snow showers but even this cold will fail to bring temperatures back to normal and might also give way to another mild push and rain for next weekend although this remains a question mark right now.
About the only thing we do know for sure beyond a week is that we will see a more serious punch of cold weather late next weekend after another rain or mixed precipitation event next weekend. Several runs of the European Ensemble have suggested that the very positive AO will continue to rule the day allowing the cold weather next weekend/early next week to lift and opening the door for more mild temperatures and potentially more rain. The GFS and its ensembles suggest otherwise; in fact, the GFS is so dramatically different beyond the 12th of December allowing arctic cold to completely overwhelm the pattern. This evolution is supported by a developing La Nina style ridge in the Gulf of Alaska and allowing the downstream trough to become expansive enough to cover most of Canada. It defies my sense of reality but it is nonetheless encouraging. It would be realistic enough to expect cold weather to expand its influence across Canada and at least become somewhat accessible to northern New England. I would not expect cold weather to be as persistent as what the GFS suggests beyond the 12th of the month.
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