Snow especially in Laurentians today, then especially in southern areas Tuesday, with dry Monday; light snow and snow squall Wednesday night in northern areas, then very cold Thursday and Friday; potential weekend snow and continued cold and active weather pattern but maybe without big storms

Plain-language summary:

Light to moderate snow will fall mostly along and northwest of the St. Lawrence River today, with the heaviest in the Laurentians. After a few snow showers along the cold front tonight, it will dry out and turn colder for Monday. A modest snowstorm will occur in southern areas, with less snow to the north, on Tuesday. Snow showers will occur along and northwest of the Appalachians Wednesday night before a snow squall ushers in very cold air Thursday into Friday. Snow is possible or likely next weekend, but how much is very uncertain. A fast-moving, cold weather pattern with frequent systems will likely continue into following week, though big storms appear less likely than originally thought.

Meteorological discussion:

Light to moderate snow along and northwest of St. Lawrence River today, heaviest in Laurentians, then brief shot of arctic air Monday 

 

A low-pressure system located in the Great Lakes region today is bringing light to moderate snow to the region, mostly along and northwest of the St. Lawrence River, with the heaviest snow in the Laurentians (locally 6-8" or 15-20 cm possible) closer to the better dynamics and also with upslope enhancement. The storm is producing lighter precipitation than the widespread heavy snowfall in the Midwest U.S. yesterday, perhaps due to getting cut off from the Gulf of Mexico moisture. The system will quickly pass to the northeast tonight, with a brief shot of arctic air behind it for Monday and a few snow showers along the front before drying out, especially in the upslope areas of the northwestern Adirondacks and Eastern Townships of southeastern Quebec. 

 

 

 

Moderate snow in southern areas, lighter snow to the north Tuesday 

 

However, another broad but weak low-pressure system that is very elongated from north to south will already be approaching from the west. The strongest piece of energy will be near the southern end of this elongation, traveling through the lower Midwest U.S. and Ohio Valley by early Tuesday and eventually into southern New England by Tuesday night. The system will strengthen and consolidate as it moves offshore the U.S. East Coast, and with the cold air to the north of the storm, precipitation will fall as snow throughout the region. The heaviest snow will be from southern Vermont to southern Maine, where heavy snow of 6-10" (15-25 cm) is likely, with amounts tapering off to the north until almost nothing north of the U.S./Canada border. There is still some model disagreement, with ICON and GFS showing a stronger, snowier scenario and the CMC and ECMWF showing a weaker storm and almost nobody receiving >6" (15 cm). This is a missed opportunity for a widespread bigger snowstorm, like what occurred many times in December and January of last winter; if the disturbance had been a bit stronger and farther east, with a stronger northern disturbance and upper-level wave train to direct the storm more northward and allow it to strengthen more, there would be a widespread 10"+ (25+ cm) snowstorm that would extend farther north.

 

Source: TropicalTidbits

 

 

Light snow along and northwest of Appalachians Wednesday night, very cold Thursday and Friday, another potential snow next weekend but uncertain how much 

 

The fast-moving weather pattern will continue. An elongated Alberta clipper will produce snow showers Wednesday night along and northwest of the Appalachians, possibly enhanced by Lake Ontario in the St. Lawrence Valley and Laurentians, with a snow squall along its strong cold front ushering in a very cold arctic air mass on Thursday, by far the coldest of the season thus far, with the Laurentians going below 0F (-18C) Thursday night. Yet another system or two with a rather complicated setup will arrive next weekend, with at least one Alberta clipper as well as a southern, more moist system over the central or southern U.S. Depending on how the disturbances interact, we could just have an Alberta clipper with light snow, our region in a dry zone between the Alberta clipper to the north and the juicier southern system to the south, or the two could combine with a widespread bigger storm. This evolution will rinse and repeat to some degree the following week, but of course the details that can't be determined this far out will matter a lot in terms of sensible weather (e.g. whether we only see minor Alberta clippers or bigger storms).

 

Source: TropicalTidbits

 

 

Source: TropicalTidbits

 

Active weather pattern still likely afterward, but big storms perhaps less likely than earlier thought

 

The bigger storm scenarios appear less likely given the although the -EPO and -NAO is allowing a lot of arctic air to flood central and eastern North America over the next few weeks, the high-latitude blocking is not enough to allow for big meanders in the jet stream and a very amplified upper-level wave train. With the strong temperature gradient and jet stream, there will be many systems, but it might be more difficult for the northern polar jet (with the arctic air) and the southern jet (with the moisture) to combine and produce big snowstorms than originally thought a week ago. It appears that the upper-level trough might be a bit too flat and its axis centered right over our region instead of over the Midwest U.S., promoting systems to move more straight west to east instead of from southwest to northeast, in which case they could strengthen more and more importantly, gather Gulf of Mexico moisture. It is still way too early to rule anything out with such a volatile weather pattern, but ensembles do show below-average precipitation is more likely in the medium to long range. On the other hand, with the cold air and lack of Gulf of Mexico warmth and moisture, thaws are unlikely, allowing what precipitation that does occur fall as snow, often a dry, fluffy snow with cold temperatures associated with Alberta clippers occurring every 2 or 3 days. There are still a few model runs showing stronger upper-level troughs moving farther south into western North America in the long-range that would result in a storm ejecting into the Plains that can tap into at least some Gulf of Mexico moisture.

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

Light snow through tonight; chilly and dry Monday, then turning milder with light intermittent rain through Wednesday night; cold with snow showers and heavier lake-effect snow Thursday and Friday, then drier next weekend, then very volatile weather pattern with big temperature swings and storms with all wintry precipitation types likely

Plain-language summary:

 

Our region has missed most of the warmth encompassing most of the U.S. over the past week, and that will continue for this upcoming week until arctic air becomes more widespread in eastern North America on Thursday. Light snow will fall from eastern Ontario to northern New Hampshire through tonight, heaviest over eastern Ontario and with rain mixing in Champlain Valley and St. Lawrence Valley in northwestern New York. It will then be chilly and dry Monday before turning milder with light intermittent rain Tuesday night into Wednesday night, but true warmth and precipitation will be limited, with only a short period of light rain expected for most, perhaps starting as wet snow in the Laurentians. It then turns cold and breezy with scattered snow showers across the region, especially in higher elevations along and northwest of the Appalachians, as well as heavier lake-effect snow bands in parts of the Adirondacks and eastern Ontario on Thursday and Friday. It will dry and clear out next weekend, with by far the coldest temperature of the season thus far, especially at night. Beyond next weekend, the weather pattern will become very volatile with big temperature swings, tight temperature gradients, and storms with all wintry precipitation types likely. There is the potential for one warmer system with wintry precipitation changing to rain early to middle of the following week and another one or possibly two colder systems a few days afterward, but this is highly uncertain, and the details of temperatures, precipitation amounts, and precipitation type will not be known until a couple of days before each system.

 

Meteorological discussion:

Our region missing out on warmth farther south, light snow today and tonight mostly New Hampshire on northwest 

 

Despite most of the U.S. having unseasonable warmth over the past week after the previous week's arctic blast, a persistent northwesterly flow of chilly air has blocked any of the warmth from reaching our region. Over the past week, our region has some of the coldest temperature anomalies of all of eastern North America.

 

Source: Climate Prediction Center

 

 

Today will continue that theme, with a weak Alberta clipper bringing light snow through tonight from eastern Ontario to northern New Hampshire, with rain mixing in for lower elevations of the Champlain Valley and St. Lawrence Valley in northwestern New York. The snow will be "heaviest" in eastern Ontario, where locally 5+ cm could fall, but amounts will taper off heading east as the system weakens. 

 

Source: Aviation Weather Center

 

 

Chilly and dry Monday, then turning milder through Wednesday night with period of light intermittent rain for most 

 

A re-inforcing shot of cold and drier air will follow briefly for Monday, but that will not last long as a strengthening storm will push from the Rockies into the Great Lakes and into central Quebec Tuesday and Wednesday, bringing southwesterly flow into the region. While the initial cold air and lack of strong southerly transport of warm and moisture from the Gulf of Mexico will once again limit the intensity of the warmup (as well as precipitation intensity and duration) in our region, it will be warm enough for rain except in the Laurentians where light wet snow is still possible at the onset as the low-pressure system passes to our north on Wednesday. Precipitation will be relatively light and intermittent.

 

Source: TropicalTidbits

 

 

Cold with snow showers Thursday and Friday, heavier in lake-effect snow bands 

 

An arctic air mass will blast into the central and eastern U.S. on Thursday and Friday, more powered by a -EPO and upper-level ridging in Alaska than ridging in western North America or high-latitude blocking, with the PNA, NAO, and AO all remaining near neutral. But with the low-pressure system over central Quebec, the cold air will first dive into the northern Plains and Upper Midwest U.S. first before heading eastward into our region, being modified over bare ground and the Great Lakes, so it won't be exceptionally cold when it reaches our region. Still, it will be colder than average for late November, and the wind will make it feel colder. There will also be lake-effect snow bands off the still warm Great Lakes, with the Lake Ontario band extending into the Adirondacks and possibly far southern Quebec, and the Lake Huron band extending into eastern Ontario. The general cyclonic circulation and lingering moisture will also lead to snow showers regardless of lake-effect snow, especially in higher elevations along and northwest of the Appalachians, though with much less accumulation than locations in lake-effect snow bands.

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

 

Very cold and dry next weekend, then likely milder middle of following week with any wintry precipitation potentially changing to rain, though still rather uncertain

 

By next weekend, an Arctic high-pressure system will be parked over our region, leading to any snow showers and clouds dissipating. Combined with lighter winds, low sun angle, and for some, still remaining snow cover, the coldest temperatures of the season so far by far will occur, especially at night. However, the PNA will then turn slightly negative, and most ensembles show a rather strong upper-level trough moving into the western U.S. With all the arctic air available, a lot of snow will fall in the Rockies and Plains, but if the system is too amplified, it will foster a strong downstream upper-level ridge in the southeast U.S. that would deflect the storm to our northwest, causing a quick warmup and precipitation type being rain except maybe starting as snow, ice pellets, and or freezing rain especially north of the U.S./Canada border, given how cold it will be ahead of the storm, especially in the low-levels. How all this plays out depends on the amplification of the weather pattern and if the system comes out in one strong piece or is split into weaker pieces, and we will not have much confidence on this until late next week.

 

Source: TropicalTidbits

 

 

Arctic air floods back in later in week, with potential for another storm, a potentially colder and snowier one but with very high uncertainty 

 

Arctic air will flood back in as soon as the storm passes, though there could be another storm to slow the progression of cold air southward, especially if the southeast U.S. ridge is not beaten down much yet by that point. Temperatures and precipitation type will greatly depend on the exact timing and strength of these disturbances and connection to arctic air. At least one of the storms around that time (end of November into early December) will likely have access to both warm, moist Gulf of Mexico air from the south and arctic air to the north, straddling along the tight temperature and moisture gradient. This kind of setup is volatile and leads to very uncertain forecasts for any individual location, as a relatively small shift can make the difference between 50F (10C) with rain and 23F (-5C) with snow or the storm being suppressed too far south for any precipitation, leaving it just cold and dry. This kind of setup also leads to warm, moist air easily overrunning cold, arctic air, a setup ripe for a wintry mix of precipitation, with our region likely to experience all precipitation types (rain, freezing rain, ice pellets, and snow) at some point, perhaps even multiple times, with details not being known until a day or two in advance. Beyond that, ensembles show more upper-level troughing dominating in eastern North America with arctic air penetrating farther south, but that is uncertain given the PNA staying only near neutral. The most confident feature is the abundance of arctic air in mid-latitude North America given the continued upper-level ridging in Alaska, even without high-latitude blocking (which although usually promotes colder weather, can actually sometimes prevent the coldest air from being involved in the weather pattern).

 

Source: TropicalTidbits

 

Light snow in northern areas this afternoon through Monday morning; longest dry spell in weeks for most of upcoming week; likely milder with rain events Friday into following week though with caveats; likely colder and maybe still stormy for end of November

Plain-language summary:

 

After bringing rain, ice, and snow last night depending on location, a storm slowing down over Maine and New Brunswick will provide light snows to northern Maine and areas along and northwest of the Appalachians this afternoon through early Monday morning. It will then dry and at least partially clear out with weakening winds through the remainder of the week, marking the longest dry spell in weeks. It then likely turns milder with rain Friday, though the weather setup is still rather uncertain, and there is still the outside chance of some areas seeing wintry precipitation. More milder surges with rain are possible or likely the following week, though it might not be as warm as some recent late fall warm periods. Colder and possibly stormy weather will likely return for the end of November, with precipitation type dependent on exact storm tracks which are uncertain at this time.

Meteorological discussion: 

 

Alberta Clipper brings more mixed precipitation changing to snow and windy conditions this afternoon into Monday morning

 

Despite a push of extremely warm (for November) air into the Plains and even the western Great Lakes, the leftover upper-level trough from the past week's arctic surge, now in Atlantic Canada, steered a more dynamic Alberta clipper than usual southeastward into our region, blocking the warmup and instead giving a round of rain, ice, and snow last night depending on location. A surge of colder air is coming in this afternoon, with any precipitation falling as snow this evening into tonight. Often times, it quickly dries out on the back side of a storm, but in this case, a deepening upper-level trough will transform into a cut-off low straight over our region, tracking from northern Vermont to central Maine through early Monday. This will lead to continued light snow in northern Maine and many areas along and northwest of the Appalachians, with heavy snow accumulation in the higher elevations. Areas southeast of the Appalachians will be too far south relative to the storm and will also receive downsloping wind off the Appalachians, leading to dry weather there. It will be breezy everywhere with a strong pressure gradient resulting from the 975 mb surface low-pressure system over New Brunswick occluding and slowing down.

 

Source: TropicalTidbits

 

At least partial clearing with weakening winds and longest dry spell in weeks later in week, then likely milder with rain at some point Friday into next weekend 

 

After Monday's storm slowly pushes east of our region by Tuesday, it will at least partially clear out with winds weakening, though without a very dry air mass in place, there could still be lingering low clouds with such an air mass at this time of year. It will feature the longest dry stretch in weeks, with the next system being a relatively-starved Alberta clipper quickly moving southeastward on Friday. Given the track to the north and southerly winds ahead of it, the already stale cold air will be scoured out, leading to mainly rain for most, though there may be wet snow or other wintry precipitation in some northern areas. The clipper will bring a reinforcing shot of modestly colder air behind it, but it will not be intense and will be relatively brief. The critical -AO, -NAO, and +PNA combination recently that brought all the cold air over the past week will be neutralizing next week, making it difficult for cold air to penetrate deep into the mid-latitudes again for a while. Arctic Canada will also remain unusually warm. It gets quite uncertain afterward, depending on how a southern system to the southwest of the clipper interacts with the Alberta clipper. The southern system will only very slowly move eastward from the southern Rockies into the Plains and then Great Lakes over the course of the week due to it being mostly cut-off from the main jet stream to the north and underneath broad upper-level ridging across western and central North America. If it comes into our region just at the right time, such as right as the modest cold air moves in behind the Alberta clipper, northern areas could at least start as wintry precipitation before changing to rain. However, the system could be delayed enough for the cold air will grow stale or could be suppressed to the south entirely. 

 

Source: TropicalTidbits

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

 

Milder weather pattern with more rain events likely the following week, then colder and potentially still stormy

 

The relative lack of wintry precipitation will likely continue for a while afterwards, though confidence is low in any details. That by itself is actually not unusual for November. The PNA will turn negative for a time, with the upper-level trough in western North America promoting a downstream ridge in eastern North America. This would promote more storms ejecting from the Rockies and tracking northwest of our region, leading to more mild surges and rain events in our region, unless there is just enough high-latitude upper-level ridging with surface high-pressure over northeastern Canada to keep low-level cooler air in our region, which is still possible if the NAO remains slightly negative and could lead to sneaky areas of wet snow, ice pellets, and freezing rain. However, there are signs that the North American weather pattern will favor more discharge of arctic air into central and eastern North America towards the end of November with -EPO and upper-level ridging in Alaska. If the upper-level trough initially sets up to our west, a lot of the cold air will go there initially, with the southeast U.S. ridge deflecting storms toward our region, perhaps leading to a stormier and snowier period, with mixed precipitation still possible if the weather pattern is amplified enough. That would be a weather pattern in which relatively small shifts would make a difference between cold and snowy conditions and mild and rainy conditions, leading to greater uncertainty.

 

Source: TropicalTidbits

 

Very amplified weather pattern to start prolonged period of early winter like weather; first widespread snow for most today through Tuesday; more snow and rain showers for northwestern areas Wednesday; drier but still chilly Thursday through next weekend with potential for more minor storm with snow early following week; uncertain afterward but probably persistent modest chill with occasional chances for snow or mixed precipitation

Plain-language summary:

 

A very amplified weather pattern will favor a persistent early-winter like weather pattern with persistent modest but not extreme cold and several opportunities for snow or mixed precipitation. Many areas will see snow today into tonight with an initial primary storm, marking the first widespread snow of the season, though it will quickly change to rain along and southeast of the St. Lawrence Valley with a narrow area of 6-10" (15-25 cm) to the northwest over eastern Ontario and the Laurentians. Any rain will change back to snow tomorrow evening for Vermont and southern/eastern Quebec, though it is still not clear how much if any precipitation there will be then as a second storm develops. Snow showers will linger along and northwest of the Appalachians into Tuesday before another disturbance brings light snow and rain showers along and northwest of the St. Lawrence Valley, perhaps enhanced by lake-effect precipitation off Lake Ontario into eastern Ontario and the Laurentians. It will turn drier but stay chilly Thursday into next weekend, with another more minor storm possible early the following week that could bring more snow if the storm track is right. There is uncertainty in the weather pattern afterward, but it seems likely that pushes of warm air from the southwest will be blocked, with a persistent flow of modest cold from the north and northwest into our region continuing, leading to more potential for wet snow or mixed precipitation if any storm arrives into our region.

 

Meteorological discussion: 

 

While our region escapes extreme cold, still first taste of winter with first widespread snow for most and narrow area of heavy snow in eastern Ontario and Laurentians today into tonight 

 

With a +PNA, -NAO, and -AO all conspiring together to produce a very amplified upper-level ridge in western North America and trough in central and eastern North America. Such a weather pattern favors a northerly flow from the Arctic all the way to the Gulf of Mexico, with temperatures at least aloft being among the coldest ever recorded for this time of year in the U.S. Deep South. Our region will not receive the core of the cold air, but will still have the first taste of winter today into tonight with a slowly strengthening storm pushing into upstate New York and then northern New England this evening producing snow on the northwestern side with enough cold air in place. The first injection of cold air arrived just in time last night with a little extension of cold surface high-pressure system over central Quebec leading to a direct shot of cold air from the north with minimal modification over mid-latitudes and the Great Lakes. This means that precipitation ahead of the main storm will fall as snow for almost everyone except southern Vermont to central/northern Maine, marking the first widespread snow of the season for most, even at lower elevations. Still, temperatures will be relatively marginal as is usually the case in early November, and warm advection will easily change any snow to rain along and southeast of the St. Lawrence Valley this evening, with the heavy snow of 6-10" (15-25 cm) occurring in a narrow area in eastern Ontario into the Laurentians where a narrow frontogenetic band of very heavy snow will sit for a few hours. A narrow area of ice pellets and freezing rain is likely mostly in northwestern New York, aided by the channeling of low-level cold air through the St. Lawrence Valley, but given that the low-level cold isn't particularly strong as it is early November, the areal extent and magnitude of any icing will be relatively minor.

 

Source: TropicalTidbits

 

Source: TropicalTidbits

 

 

Source: Climate Prediction Center

 

 

Some backside snow/snow showers Monday evening into Tuesday; another disturbance with light snow/rain showers on Wednesday along and northwest of St. Lawrence Valley

 

The main system will move into eastern Quebec by Monday, but a secondary system will develop and strengthen along the U.S. East Coast and move almost due northward, a symptom of the very amplified weather pattern. An area of precipitation will develop on the western side, likely over Vermont, New Hampshire, and southern and eastern Quebec, with any rain changing back to snow as cold air slowly filters in from the west. While rain changing to snow usually does not amount to much, the strong upper-level dynamics may be enough to lead to a burst of snow for a few hours from Vermont into central Quebec. This is a rather tricky situation with models still disagreeing on just how pronounced this backside precipitation will me. Regardless, snow showers will then continue along and northwest of the Appalachians into Tuesday as the system joins into a occluded, broad, and strong cyclone over northeastern Quebec on Tuesday. Colder air will also filter in from the west but will be modified as it is not directly from the north, and eventually, winds will turn to southwesterly by Wednesday as another disturbance moves through which will produce light snow and rain showers, possibly enhanced by lake-effect bands off the Great Lakes, including a band off Lake Ontario extending into eastern Ontario and the Laurentians. Given how far north the disturbance is, almost all the little precipitation that will fall will be confined to the St. Lawrence Valley on northwest.

 

Source: TropicalTidbits

 

 

Dries out with at least partial clearing Thursday into Saturday with another shot of chilly air; possibly another system with uncertainty in precipitation type early the following week

 

The weather pattern will then slowly de-amplify and move eastward as an upper-level trough moves into the western U.S. (+PNA turning to neutral or slightly negative) triggering an upper-level ridge to build downstream in the central U.S. However, behind Wednesday's disturbance, the wind will turn back to the west and then northwest, with a surface high-pressure building in from northern Ontario, providing drier weather and another shot of chilly weather through next weekend, though it won't be true arctic air. Also, the -NAO and -AO and associated high-latitude blocking will remain, and combined with an upper-level trough stuck underneath over Atlantic Canada, the deep northwesterly flow will prevent most or all of the warmth building in the central U.S. from entering our region. The surface high-pressure could lead to some clearing of clouds at least before a disturbance could move southeastward from northern Ontario to our region early the following week, and it could be cold enough for more snow depending on the storm track, even though southeastward moving storms like that do not carry a lot of moisture due to the lack of deep southerly flow of moisture from the Gulf of Mexico or western Atlantic. The storm could also be suppressed to the south, leaving our region dry, if the blocking pattern is too strong.

 

Source: TropicalTidbits

 

 

Uncertainty in weather pattern after next weekend, but possibly persistently modestly chilly with occasional wet snow or mixed precipitation opportunities 

 

Beyond next weekend, there are conflicting signals in the weather pattern. The near-neutral or slightly negative PNA would promote slight upper-level troughing in western North America and ridging in eastern North America, which by itself normally would favor warmth in our region, but in this case, the high-latitude blocking (-NAO and -AO) as well as trough in Atlantic Canada will also be persistent and attempt to thwart any warmup coming from the southwest, especially if Canadian surface high-pressure systems across Ontario and Quebec continue to dominate and promote more northerly instead of southwesterly flow. Yet if there is a strong enough storm ejecting out of the Rockies that moves northeastward, our region will eventually get into the warm sector with southerly or southwesterly flow. As such, there is considerable uncertainty in the temperature pattern, but it appears that our region could be one of the few in North America to see sustained near-to-below average temperatures, mostly a result of persistent chilly but not particularly cold weather with a lack of true Arctic air and most of the cold air still being in northern Asia with anomalous warmth still dominating over northern Canada. This is occurring while the southern and central U.S. becomes persistently warm. The neutral or slightly negative PNA could also allow for storms ejecting out of the Rockies to reach our region instead of being suppressed to the south, and with surface high-pressure to the north delivering at least modest cold air, there could be more opportunities for wet snow or mixed precipitation with temperatures likely to be marginal with any event given the lack of true arctic air and that it is still only mid-November at that time. Suppression of storms is also a possibility, leaving our region relatively dry.

 

Source: TropicalTidbits

 

Dry today but still cloudy for many; breezy Monday and Tuesday with rain later Monday; the changeable weather pattern with rain late Wednesday into Wednesday night and next weekend, first chance of widespread snow early following week, and coldest air of season Thursday into Friday and middle of following week

Plain-language summary:

 

Today will be a dry day across our region but with low clouds still dominating along and northwest of the Appalachians. After a brief clearing this afternoon into tonight, it will turn breezier with a several-hour period of light to moderate rain Monday afternoon and evening. The wind will persist on Tuesday with more clouds and seasonably cool temperatures. A very changeable weather pattern typical of November will then ensue, with frequent disturbances and fronts bringing clouds, precipitation, and temperature swings that will likely help continue to ease the drought at least slightly. Rain and very high-elevation snow is likely late Wednesday into Wednesday night, especially along and south of the U.S./Canada border, before coldest air mass of the season so far arrives Thursday into Friday. It warms up with rain likely next weekend before it turns colder with possibly the first chance of widespread snow early the following week before it turns even colder before warming back up.

 

Meteorological discussion:

 

Cloudy skies persist today, then brief clearing this afternoon into tonight before rain Monday afternoon and evening and staying cool but not too cold through Wednesday  

 

Despite the big storm that brought heavy rain to our region on Thursday and Friday being long gone and way off to the northeast, with higher surface pressure slowly nosing in with no precipitation, low clouds continue to dominate much of the region along and northwest of the Appalachians. This is very common in November as all the moisture picked up by the unfrozen Hudson Bay and lakes and rivers across southern and eastern Canada gets trapped underneath a low-level and subsidence inversion while the sun angle is too low to break up the clouds. However, these clouds will gradually go away briefly this afternoon into tonight from west to east as stronger dry westerly to southwesterly flow takes over tonight before another disturbance/low-pressure system traveling into Quebec on Monday brings breezy conditions and a several-hour period of light to moderate rain in the afternoon and evening to our region ahead of a diffuse cold front. The cold front will maintain the cool air mass in our region, but once again, the air is not that cold as there is little connection with the Arctic, and Arctic Canada is still much warmer than average for this time of year. Also, the flow will be mostly out of the west, leaving more time for modification of the cold air mass, instead of a direct and stronger cold shot from the north. There will likely also be a fair amount of low-level clouds again, as well as a strong breeze, typical of November.

 

Source: College of DuPage and TropicalTidbits

 

Source: TropicalTidbits

 

Rain and high-elevation snow later Wednesday into Wednesday night, coldest air of season Thursday into Friday 

 

With the NAO turning positive, high-latitude blocking disappearing, and the mid-latitude jet stream strengthening and pushing south into our region more often, we will enter a more changeable weather pattern with disturbances and fronts crossing our region every few days. With the big rainstorms over the past 2 weeks, and these future disturbances bringing clouds and at least light precipitation rather frequently with relatively cool temperatures, and the low sun angle leading to low evaporation, the drought will likely continue to ease at least slightly. Another low-pressure system will strengthen as it crosses our region later Wednesday into Wednesday night, bringing another period of light to moderate rain for most of the region, though exactly who gets the most rain depends on the strength and location of the storm, which is still a bit uncertain. For now, areas just south of the U.S./Canada border look to get the heaviest rain. Given the marginally cold air, high elevations above 2000' (600 m) could see wet snow. A more direct and stronger shot of cold air, the coldest of the autumn so far, from the north or northwest will follow Thursday into early Friday. The colder and drier air with relatively high surface pressure will likely lead to more clearing and give the first freeze to anybody who hasn't yet seen a freeze. Many areas will likely drop below 25F (-4C), which is not exceptional for early November but would be notable this year given the lack of really cold air masses in Canada thus far.

 

Source: TropicalTidbits

 

Source: Climate Prediction Center

 

Changeable weather pattern with warmup with rain next weekend, then cools down with first chance of widespread snow, then warmup 

The surface high-pressure system will quickly move off to the east and be replaced by a low-pressure system moving into central Quebec, well north of our region, next Saturday, leading to breezy southerly winds, a notable warmup, and some rain. However, this will quickly be followed by a cooldown afterward and perhaps another weaker disturbance/low-pressure system for the following Monday or Tuesday. This second system will likely track farther south, leaving our region possibly north of the low-pressure center and on the cold side of the storm. The cold air and farther south storm track is aided by a +PNA and associated upper-level ridging in western North America and troughing in eastern North America, with the NAO and AO both decreasing to slightly negative, aiding in the cold air pushing southward into our region. Depending on how these systems interact and which one is stronger, this second system could provide the first real chance of widespread snow for our region, though the cold air available probably isn't strong enough yet for a big snowstorm and would favor a wet snow with some melting. Even colder arctic air could follow for a couple of days before the +PNA likely breaks down, with more upper-level troughing in western North America and ridging in eastern North America, leading to a warmup and end of any winter preview.

Source: TropicalTidbits

Source: TropicalTidbits