Nor'easter skirts region with snow from southern Vermont to central Maine while it stays dry to the northwest; then stays modestly cold with light snow Wednesday and possible storm Friday; brief thaw Saturday with light rain and snow, then colder before potentially volatile weather pattern with temperature swings and storminess in early March

Plain-language summary:

 

A rapidly-strengthening Nor'easter will bring the heaviest snow south of region, but at least moderate amounts are still likely from southern Vermont to central Maine through Monday, while it stays dry and even mostly sunny to the northwest. It then stays modestly cold with light snow likely on Wednesday and a potential though likely not big storm Friday. A brief thaw Saturday will likely be followed by a short period of rain and snow Saturday night before turning very cold for at least a few days. It could turn milder in early March, but it could also just turn more volatile with big temperature swings and potential for storminess and even snowstorms if the cold arctic air from the north meet up with the strengthening warm and moist air masses from the south at the right time. The first chances of bigger storms are around March 2 and March 5.

 

Meteorological discussion:

 

Rapidly strengthening Nor'easter brings heaviest snow south of our region through Monday but still at least moderate amounts likely from southern Vermont to central Maine, while it stays dry to the northwest 

 

It has been a messy weather pattern, but rather surprisingly, a seemingly relatively weak and broad upper-level low currently over the eastern Great Lakes will explode into a rapidly strengthening Nor'easter just off the U.S. East Coast tonight into Monday. With relatively weak flow aloft due to a blocking high-pressure to the north, the Nor'easter will move relatively slowly, delivering feet of snow to southern New England. It is the kind of storm that has not happened in years. However, the ever present suppressive Atlantic Canada upper-level low that is so prevalent this year will suppress the storm mainly to the south and prevent a quick turn north. It will move slowly northeastward and will likely bring at least moderate snow to southern Vermont to central Maine. However, this area will be near the northwestern edge of the snow area, so even small shifts will cause big differences in snowfall totals, and Nor'easters that explode like this just off the coast are notoriously tricky to forecast, and models were until yesterday still disagreeing on the details. In fact, a few days ago, almost all models had the storm weaker and farther offshore, bringing little impact to land areas, except the GFS which has consistently shown a stronger storm closer to the coast and has actually done relatively well over the past several days in contrast to the rest of the winter. Nonetheless, due to the suppressive nature of the weather pattern, the Champlain Valley northwestward will stay dry and even mostly sunny, except for a few light snow showers in eastern Ontario today from the predecessor weak disturbance which will disappear tonight as the Nor'easter consolidates all of the energy and moisture. With such a strong low-pressure system, areas in the snow zone will see strong winds, making for possible blizzard conditions, with winds becoming weaker heading northwest. There will also be a sharp cut-off between heavy snow under one of the frontogenetic bands and little or nothing with sinking air just to the northwest.

 

Source: TropicalTidbits

 

This explosive, slow-moving, and somewhat blocked setup is a bit surprising given the -PNA and +NAO, but the high-latitude blocking appears to be directly north of our region in northern Quebec as opposed to over Greenland. This is also allowing storms to tunnel underneath the block despite the -PNA normally allowing storms from the Rockies to track northeastward easily, especially with a +NAO. Also, a strong blocking upper-level ridge in the Gulf of Alaska is displacing the main jet stream much farther south than usual over all of North America. This is one caveat to simple teleconnection indices like the PNA and NAO. However, that pattern will be breaking down over the next week.

 

Source: Climate Prediction Center

 

Source: TropicalTidbits

 

 

Weakening clipper brings light snow Wednesday, possible storm Friday though could be suppressed south and weak again, with previously expected thaw to fail to occur

 

After the Nor'easter moves out Monday night, slightly colder air will filter in from the north, but the true arctic air will stay to the north. Still, with the direct northerly flow, frozen lakes, and widespread deep snow cover, temperatures will be modestly below average. Surface high pressure will bring mostly sunny weather on Tuesday before an Alberta clipper moves into the region later Wednesday and brings light snow, though it appears to be weakening and moisture-starved given its track to the east-southeast, like most of the systems this winter. With southerly flow, the southern Adirondacks and Laurentians will see upslope enhancement, making for moderate snow amounts, possibly >4" (10 cm) locally. Another disturbance could follow behind the clipper, pick up some Gulf of Mexico moisture, and move into our region for Friday, though most models show it being relatively weak and suppressed to the south. This is quite a shift from just a few days ago, when most models showed it possibly warming up enough for it to rain, but typical of this winter, especially the past month, the weather pattern keeps shifting to more of a upper-level ridge in western North America and trough in eastern North America than first modeled. However, it is a rather difficult forecast as pieces of energy will eject out of a slow-moving upper-level low in the eastern Pacific underneath a strong blocking upper-level ridge in the Gulf of Alaska through early next week. Such upper-level lows are always very tricky to forecast, and given that this one will be over the ocean where there is less data for a few more days, it will be even trickier to forecast. Even model initializations are considerably different. Friday's system will highly depend on the exact nature of the energy coming out of the upper-level low (straighter and strung out would mean weaker and farther south storm, whereas a more curved, consolidated piece would mean a stronger and farther north storm). Nonetheless, a more suppressed pattern with much less precipitation than originally expected would fit the theme of most of this winter.

 

Source: TropicalTidbits

 

 

Brief thaw Saturday with a little rain and snow Saturday night, then arctic air returns 

 

With the rising EPO and positive NAO, the blocking pattern will fade away next week, and there will actually be a stronger than average temperature gradient and jet stream strength by next weekend. A clipper will likely track well north of our region on Saturday, bringing a brief one-day mostly dry warmup powered by the stronger late February sun and southwesterly flow. The clipper's cold front may bring a short period of rain and snow Saturday night (rain more likely at lower elevations and snow more likely at higher elevations). Given the cold, dry air mass shortly preceding the clipper and the clipper's northern track, there is unlikely to be any appreciable Gulf of Mexico moisture involved, making total precipitation amounts light, unless there is a secondary wave that forms on the tail end of the clipper's cold front, which is somewhat possible but not likely. Despite it being a week away, models are actually in rather good agreement on this general scenario, perhaps due to the fast upper-level flow and only one main system (being the clipper). If next week's storms are weak, moisture-starved, and/or suppressed as most models currently show, parts of the region, especially northwestern Maine into the Laurentians, could have one of the driest Februarys on record. Despite it being the start of meteorological spring, the arctic air mass behind the clipper appears to be quite impressive and coming directly out of the north with no modification, with an ideal surface high-pressure placement just to our north over Quebec. It could reach -4F or -20C in many areas if current projections are correct and the coldest air mass is timed well with a clear, calm night.

 

Source: TropicalTidbits

 

 

Strong temperature contrasts raise potential for wild temperature swings and storminess while Arctic air nearby keeps snow potential alive in early March

 

For the following week, models mostly agree on an impressive amount of arctic air building across Canada fighting with a strengthening southern U.S. ridge. This normally is a favorable setup for storminess for our region, but given how this winter has gone, I have to be a bit skeptical. Still, given the strengthening warm and humid air masses in March to our south and the climatologically less stable air masses combined with the arctic air masses still within reach, it would not take much to spawn a storm that has strong dynamics and at least some Gulf of Mexico moisture that could bring a more substantial widespread storm to our region, as rare as that has been lately. Arctic air means that snowstorms are still possible, and if a system can ram warm and moist Gulf of Mexico air straight into the fresh cold air masses, a widespread heavy snow will result. The first chances are around March 2 and March 5. March can be a wild month with wild temperature swings, and given the stronger than average temperature contrasts expected, that could be even more so this year. Some models are also showing just high-pressure dominating both at the surface and aloft, leading to mostly dry weather as the March sun angle quickly moderates arctic air masses. Still, I wonder if the models will back off on any real upper-level ridge in the southeast U.S., shifting it to our west instead, leading to a more suppressive pattern that has dominated most of this winter. The frozen Great Lakes and widespread deep snow cover will act as negative feedbacks or roadblocks to any big thaws. Small changes in the upper-level flow will make a big difference in sensible weather in our region with temperature gradients this strong.

 

Source: TropicalTidbits

 

Source: TropicalTidbits

Mostly sunny this weekend, then milder through Tuesday with very minor snows; colder later Wednesday through rest of week with storminess possible Friday through following Monday; then cold and dry for a few days before possible thaws and storminess

Plain-language summary:

 

It is a quiet, seasonably cold, and mostly sunny weekend weather-wise as a moisture-rich storm misses to our south again. It will then turn milder through Tuesday with very minor snows late tonight and Monday night. It then turns colder late Wednesday through the weekend with storminess possible starting Friday but the overall weather setup is slow-moving, messy, and uncertain. It then turns cold and dry for a few days before potential thawing and storminess for the last week of February.

 

Meteorological discussion:

 

Mostly sunny this weekend, then milder through Tuesday with very minor snows 

 

It is a quiet and mostly sunny weekend weather-wise as a moisture-rich southern jet disturbance to the south will be pushed out to sea by an unfavorable suppressive zonal jet stream configuration, making for a missed opportunity for a big snowstorm that some models showed a week ago, typical of recent winters. It will be seasonably cold or somewhat colder than average, especially at lower elevations which are actually colder than higher elevations due to the clear skies, widespread snow and ice cover, and surface high-pressure overhead that while is not arctic in nature, is sort of generating its own low-level cold with weak wind underneath the inversion aloft. 

 

Source: TropicalTidbits

 

A weak, stretched-out piece of energy extending north of the main storm will bring a little snow to the Adirondacks and maybe eastern Ontario and southwestern Quebec tonight, but accumulations for most will be minimal. However, the persistently cold weather pattern is changing, with a -PNA and associated western North American trough, not seen much this winter, promoting an upper-level ridge in the central U.S. Meanwhile, not far behind, an elongated clipper whose center will pass over northern Quebec will bring light precipitation all the way down to the Adirondacks and northern New England Monday evening, likely as snow for most, though the low-levels are warm enough for a bit of rain or freezing rain in the downslope-warmed areas of the southwestern St. Lawrence Valley and far northwestern Adirondacks. Accumulations will be light for almost everyone regardless. Given the clipper's track and southerly winds, the heaviest snow will likely occur in the Laurentians. After that, with some clearing of clouds and the stronger February sun, Tuesday will be the warmest day in a month or more, with many lower elevation locations reaching or exceeding 40F (4C). 

 

Source: Climate Prediction Center

 

Turns colder later Wednesday through rest of week, with moisture-rich storm suppressed to the south again

 

However, an arctic surface high-pressure will nose into Quebec behind the clipper on Wednesday, leading to low-level cold air from the north to enter our region, ending the brief thaw and squashing the real warm air to the south. The associated upper-level trough will dive into Atlantic Canada, and the northwesterly flow aloft in our region will again suppress the first storm ejecting out of the Rockies resulting from the -PNA pattern to the south of our region. It is amazing how good this Atlantic Canada trough is at suppressing rich Gulf of Mexico moisture this year! This is yet another missed opportunity at a bigger storm in our region, perhaps except southern Vermont to far southern Maine. It is also a bit surprising this time given that the high-latitude blocking is weakening (NAO actually turning positive) and models showed a potential thaw several days ago, but this winter just has not favored big, moist storms to come from the southwest, with Atlantic Canada upper-level troughs seemingly always cutting off the otherwise moist southwesterly flow. The suppressive flow will not only push the precipitation south of our region, but also make the area of precipitation very narrow, with snow only on the northern edge of it.

 

Source: TropicalTidbits

 

Uncertain and messy weather pattern Thursday through following Monday with multiple chances of storminess, though unlikely to get any one big storm

 

Beyond Thursday, the weather becomes increasingly uncertain and messy as multiple disturbances eject out of the broad, slow-moving upper-level trough in the western U.S. through next weekend. The disturbances will track along a battlezone between the warm, moist Gulf of Mexico air to the south and arctic air to the north that is trying to squeeze the warmth and moisture southward. It is also not clear how slowly the Atlantic Canada upper-level trough will move; some models show it getting reinforced and getting cut-off from the main polar jet to the north, causing it to meander around there until next weekend, which would leave our region dry, especially northern areas, as the confluence and west-northwest flow aloft suppresses all the disturbances to the south and weakens them, an amazing outcome given all the storminess entering the western U.S. However, other models are showing it moving out faster and too far east to affect our weather by later Friday, which would allow a second storm to move in and produce snow and possibly mixed precipitation in southern areas by Saturday. There might even be a third storm for the following Monday, but how all these pieces interact is a big question mark, and I wonder if there could be too many disturbances for any one of them to be a major storm, a frequent occurrence in recent winters. It also appears to be a rather slow-moving weather pattern with the upper-level troughs almost becoming cut-off, making the weather especially difficult to predict.

 

Source: TropicalTidbits 

 

Cold and dry for middle of following week, then possible thaws and resumption of storminess

 

After the series of disturbances, it will likely turn cold and dry again for a few days as a surface high-pressure likely coming out of the arctic settles in as the upper-level ridge briefly returns to the western U.S. However, beyond that, another upper-level trough is likely to enter western North America, perhaps farther north than the one this upcoming week. Many models are showing this to promote a storm to track farther north from the central Rockies to north of our region, leading to a thaw and rain. However, they also showed this at times for this upcoming week, and I am a little skeptical for now. All it takes is one well-timed disturbance to bring arctic air just ahead of the Rockies storm, and it would thwart the thaw and lead to snow instead. Long-range signals point to a southern U.S. ridge and some upper-level troughing in western Canada appear to be favored, a bit different from most of this winter but more typical of a La Niña winter. While not the ideal setup for big snow and storminess and especially the (now rare) Nor'easters, it is perhaps a less blocked weather pattern with more ups and downs in temperatures and regular storms criss-crossing the U.S. and southern Canada without necessarily being suppressed to our south as much. That also opens the possibility of thaws if the storms are stronger and track farther north. However, western Canada appears very cold, and some of that is likely to reach our region. Ideally for big snows in our region, we would want upper-level troughs digging just to our west or southwest with an upper-level ridge over Atlantic Canada to prevent suppression and allowing the storms to intensify as they approach our region, but that appears to be very rare in recent winters.

 

Source: TropicalTidbits

 

Extremely cold and sunny through Monday before moderating for rest of week; burst of snow late Tuesday, snow showers on Wednesday, then drier rest of week; small chance of snow following Monday but more likely thaw with rain after before turning colder again and possibly stormier

Plain-language summary:

 

It will be extremely cold and sunny through Monday before moderating for the rest of the upcoming week. A burst of snow Tuesday afternoon and evening is likely, with lingering snow showers occur on Wednesday before likely drying out for the rest of the week with typical February cold. There is a slight chance for a snowstorm for following Monday, but it is more likely to be dry with a warming trend, with a thaw and modest rain likely for the middle of the following week especially in southern areas. It will likely turn colder again afterward, perhaps accompanied by more storminess.

 

Meteorological discussion:

 

Extremely cold and sunny through Monday

 

A very cold arctic air mass is in place now, with the air coming straight from the north-northwest with minimal modification over cold snow-covered ground, with even highs struggling to get above 5F (-15C) along and northwest of the Appalachians. This is despite almost full sunshine, as clouds from yesterday's clipper have cleared for most. These sunny days typically become more common in February as the arctic air masses become really dry with all the lakes and rivers frozen and not able to add moisture into the air to form clouds. Despite the cold air mass, the wind caused by the pressure gradient between the surface high-pressure to the west and the broad low-pressure over Atlantic Canada that is very slow to move away due to the high-latitude blocking (-NAO) will prevent ideal radiational cooling and temperatures from dropping very quickly at night, perhaps except for eastern Ontario and northwestern New York, which will be closer to the surface high-pressure center and therefore experience lighter winds.

 

Source: TropicalTidbits and HYSPLIT

 

 

Gradually turning milder later in week with burst of snow Tuesday afternoon and evening and snow showers Wednesday

  

This will be the last very cold arctic air mass for at least a couple of weeks, or perhaps even until next winter. For the first time in weeks or perhaps this whole winter, the upper-level ridge in western North America will break down for a prolonged period, possibly more than a week, as the Pacific jet becomes stronger and pushes storms into the western U.S. This will relieve at least slightly the incredible snow drought in the warm and dry winter they have had so far. The more active Pacific jet will also cut off access to the arctic air for a while, with the AO turning neutral for a while after being strongly negative for almost a month. The upper-level troughing in western North America will promote upper-level ridging farther east across the central and southern U.S., but high-latitude blocking, especially over Greenland (-NAO), will trap a broad upper-level low or trough across Atlantic Canada which will stop any push of truly mild air from the southwest into our region for the upcoming week. Instead, the arctic air will just grow stale, and a low-pressure system in northern Ontario and the northern Great Lakes will push into our region, with its push of milder air into the low-level cold air in our region leading to a burst of at times moderate to heavy snow Tuesday afternoon and evening. The low-pressure system will then slide east-southeastward into Atlantic Canada Wednesday into Thursday, reinforcing the broad upper-level low there, with lingering snow showers and near average temperatures in our region. A widespread 2-5" (5-12 cm) is likely for most of the region, perhaps up to 6" (15 cm) in eastern Ontario where the dynamic forcing looks a little stronger.

 

Source: TropicalTidbits

 

 

Likely dry with typical February cold Friday into next weekend, with slight chance of a snowstorm more likely for southern areas for following Monday 

 

Multiple disturbances in the southern jet will travel west to east from the West Coast to the East Coast later in the week, being largely separate from the polar jet that will have retreated way to the north and weakened as the arctic air gets scoured out. The more active southern jet, which we have not seen much of this winter so far, could be a symptom of the La Niña weakening. Fittingly however, the blocking pattern and associated suppressive west-northwesterly flow will likely just squeeze the disturbances in a way that prevents them from strengthening and also shunts them out to sea well to the south of our region, leaving our region to gradually dry and clear out as surface high-pressure approaches, though there is a chance of a weak northern branch disturbance bringing a bit of snow some time over the weekend. The surface high-pressure will only be modestly cold, with the arctic air being locked to the north. Some model guidance is showing one of the southern jet disturbances ejecting out of the Rockies next weekend just as the Atlantic Canada upper-level trough pulls away to the northeast as the high-latitude blocking weakens for a while. If this scenario is correct, the disturbance could gather moisture from the Gulf of Mexico, causing latent heating and strengthening the storm as it heads northeastward, leading to a snowstorm across at least southern parts of our region for the following Monday as the air is still likely cold enough for snow at this point. This would have little or no boost from interaction with the polar jet given the polar jet's retreat, and would also require the disturbance to almost cut-off in the southwest U.S. and then move slowly enough to wait for the Atlantic Canada trough to pull away but yet remain strong and consolidated enough and just far enough north to feel a bit of the northern jet. Most models are currently showing the disturbance being too weak or far south to feel any connection with the northern jet and just gets shunted underneath the Atlantic Canada trough. However, models are notoriously poor at resolving the timing and intensity of these kind of slow-moving systems in a split flow, and have been varying wildly run-to-run, so it is too early to rule out any scenario.

 

Source: TropicalTidbits

 

 

Source: TropicalTidbits

 

 

At least brief thaw likely later in following week, especially in southern areas, with modest rain

 

For the following week, there is increasing multi-model ensemble agreement on at least a brief thaw occurring, especially in southern areas, even if is still too early to guarantee this scenario. The frozen Great Lakes, cold ground, and extensive snow cover do not appear sufficient to fight an overwhelmingly amplified western U.S. upper-level trough that will promote a strong eastern U.S. upper-level ridge and promote a storm track cutting into the Great Lakes and then into Quebec for at least one storm. The high-latitude blocking weakening (AO turning positive) and lack of arctic air preceding this storm also favors this type of storm track and a thaw with the first rain in several weeks. There are not indications of a particularly heavy rain for now given the broadness of the low-pressure system and lack of concentrated areas of forcing for ascent. It is worth noting though that this scenario is not guaranteed yet, and there are still some ensemble members with a less amplified scenario and/or an antecedent cold shot timed just right to avoid a thaw and lead to the storm producing at least some snow and/or ice for our region.

 

Source: TropicalTidbits

 

 

Likely turning colder afterward with possible storminess 

 

Beyond the thaw, colder air appears likely to return for late February as the weather pattern de-amplifies slightly. The continued -PNA will likely promote more upper-level troughiness and storminess in western North America, which would still favor some upper-level ridging in eastern North America, but it looks weaker, allowing some cold shots to come in especially for our region on northward, even though the core of the cold air looks to set up in western Canada instead. If it sets up right, there could be an active storm track from the Rockies into the Great Lakes or New England, a favorable track for storminess and snowiness for our region, with the storms able to pick up Gulf of Mexico and western Atlantic moisture, unlike the clippers that have been more dominant this winter so far. This might be more likely given that we will mostly lose the -NAO that has tended to suppress these storms (though there have not been many to begin with given the +PNA and western North American upper-level ridging and dryness that has dominated this winter). There also appears to be just enough high-latitude blocking and cold feedbacks (frozen Great Lakes, widespread deep snow cover, and cold ground) to prevent most of the storms from tracking too far north and bringing thaws with mild rain. However, we might be sort of "playing with fire" in this scenario, with not a big separation between a big snowstorm vs a messy wintry mix vs mostly rain given the strong temperature gradient.

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

Somewhat moderating cold and mostly dry through Thursday except a little snow for northern areas Tuesday into Wednesday; minor snow likely Friday to Saturday; very cold again after through early following week, then maybe stormier and not as cold

Plain-language summary:

 

It will be dry with cold but not frigid temperatures and mostly clear skies through Monday night, and the cold will moderate somewhat through the week. A little snow is likely in northern areas late Tuesday into Wednesday before drying out again for Thursday. A more widespread minor snow event is likely Friday into early Saturday, with a small chance of a heavier snowfall in Maine. It turns very cold and likely dry again Sunday into early the following week. Storminess could return with moderating cold later the following week into mid-February.

 

Meteorological discussion:

Mostly dry with slowly moderating cold through Thursday, except a little snow in northern areas late Tuesday into Wednesday 

 

As expected, the rapidly intensifying Nor'easter is way too far to the southeast to bring any snow to our region, instead simply sucking all the clouds and moisture with it as a piece of energy connecting to the suppressive western Atlantic upper-level trough pushes it out to sea. Instead, northerly flow of dry air will dominate through Monday night as a surface high-pressure system noses in from central Canada, with mostly clear skies, which have not commonly lasted that long this winter. Winds will also lighten, allowing temperatures to plummet at night away from urban areas and large bodies of water given the extensive snow cover. 

 

Most of the arctic air is actually drilling southward into Florida and is not being replenished, so while it is cold today, it is not nearly as anomalous as in areas farther south and will grow stale through Tuesday. A weak, slow-moving clipper will bring intermittent snow showers along and northwest of the Appalachians Tuesday into early Wednesday, though accumulations will be <2" (5 cm) for most. There will also be a weak disturbance in the subtropical jet with more moisture, but fittingly for recent years, it will be too far south with the wrong jet stream configuration to allow it to interact favorably with the clipper to the north, leading to two separate and weaker systems. A re-inforcing shot of cold air will come behind the clipper, though it will not be arctic, instead being just slightly colder than normal. More surface high-pressure and dry weather will ensue through Thursday. The suppressive cold, dry weather pattern is driven by a classic combination of western North American upper-level ridging (+PNA) and high-latitude blocking (-NAO and -AO), with the western Atlantic trough being especially important in suppressing any southern jet stream storms to the south. It is actually not a particularly arctic weather pattern, but the preceding cold weather, extensive snow cover, ice cover over the Great Lakes, and winds directly from the northwest are combining to produce an extended period of cold weather.

 

Source: TropicalTidbits

 

Minor snow likely Friday into early Saturday with small chance of heavier snow in Maine, then very cold again for Sunday into early following week

 

By Friday, a stronger clipper will dive southeastward into Quebec with another piece of energy hanging back to the southwest. It is uncertain how these two pieces of energy will interact with each other, though most indications are that it will be a widespread light snow later Friday into early Saturday that moves out by later Saturday, with an elongated area of light snow but without much moisture access to the Gulf of Mexico or western Atlantic. There have been a few rogue model runs showing a more amplified upper-level trough associated with the whole setup that would dig south, allowing the piece of energy hanging back to the southwest to form a rapidly-strengthening Nor'easter that slows down, picks up western Atlantic moisture, and brings heavy snow to eastern New England, especially Maine, but models tend to overdo these scenarios in the medium-range, and recent history argues against this scenario. Models have been trending toward the clipper staying too far north to interact favorably with the other disturbance, leaving a disorganized and elongated area of light snow. Regardless of how this turns out, a fresh and very cold arctic air mass will move in directly from the north behind the clipper for Sunday and into early the following week, likely with clearing skies.

 

Source: TropicalTidbits

 

 

Source: TropicalTidbits

 

Possibly turning stormier and snowier and not as cold later following week into mid-February 

 

The following week is a source of big uncertainty. The upper-level ridge in western North America will finally break down, with the Pacific jet becoming more active, allowing storms to move into the western U.S. and even into the Rockies with more regularity, a rarity this winter so far. The uncertain part is how suppressive the weather pattern will remain in eastern North America. A few days ago, models showed the Greenland blocking and upper-level trough in Atlantic Canada being very strong and slow-moving, suppressing any storm coming out of the Rockies to the southwest of our region or just weakening it. However, over the past couple of days, models are showing the suppression and blocking being a bit more relaxed, which would allow at least some of the storminess to push northeastward into our region, ending the prolonged dry spell, with precipitation type likely being snow at least at first given the abundance of cold air in front of it. Such a pattern would also allow for at least modestly milder air to dominate instead of arctic air masses. If the western North America upper-level trough continues with the western Atlantic trough and Greenland blocking retreating a bit more, it is even possible that mixed precipitation occurs during one of the storms starting mid-February, though I do not think this is likely for now. While persistent upper-level troughiness in western North America often spells upper-level ridging and warmth in eastern North America, I suspect that the leftovers of the high-latitude blocking pattern, unusually extensive snow cover, frozen Great Lakes, and cold ground will feed back into the weather pattern enough to prevent much if any thawing in our region for a while, even if temperatures climb to above average levels. At this time of year, such a pattern could actually be snowier due to the storminess coming out of the Rockies, as opposed to a suppressive cold and dry northwesterly flow weather pattern that we have seen often this winter.

 

Source: TropicalTidbits

 

Source: Climate Prediction Center