Major Storm On The Way For Eastern Canada

Winter Storm Forecast Discussion
A major storm is forecast to form across the southern plains states before running northwards along the spine of the appalachians. This major storm is forecast by all the major forecast models including the EC, GFS, NAM and CMC. As this storm propagates northwards enough cold air will be in place across the north to produce a swath of heavy snow across parts of ontario and quebec wednesday night into thursday. The european and canadian models are further east then the NAM and GFS with this storm developing a secondary low off of the east coast earlier in time. This shifts the highest amounts of QPF into the interior northeast and quebec but also allows higher snowfall ratios to develop within these bands. The GFS and NAM are further west, the NAM the most extreme causing more QPF for southern and eastern ontario but lower snowfall ratios as more warm air is pulled northward. In any case a major snowstorm is headed towards southern and eastern ontario as well as quebec on all the models. At the moment i believe that the middle ground is the way to go and i am in line with the GFS on track with a stronger inland low up the apps into ohio and then a secondary off of the east coast near coastal new jersey. The primary low will have plenty of precipitation to work with as it picks up gulf moisture on its way north. An initial band of heavy snow will develop and move into southern ontario wednesday night continuing into thursday morning before tapering off in the afternoon. Eastern ontario and quebec will begin to be effected a little later by the early morning hours thursday into the evening. This storm will be capable of producing a heavy band of snow on the NW side for a 10-14 hour period. QPF amounts of 0.8-1.3" are likely from niagra falls through toronto and hamilton north along the 401 to quebec city. Amounts will decrease as you move west and areas hardest hit include hamilton and niagra, montreal, ottawa and the western shores of lake ontario. This storm will cause major problems to travel on one of the busiest shopping days of the year so motorist are asked to be prepared. Conditions may be even more dire across the ottawa region where the snow depth is already very high as a result of the previous snow storm. Snowfall ratios will range from 10:1 to as high as 20:1 if the euro is correct causing a general 20-30cm swath along the 401 with higher amounts possible. Totals may be enhanced in areas along the south and west shores of lake ontario including Hamilton, niagra, oakvile and toronto due to LES enhancement. This may be caused by an E/ENE wind forecast to develop around the strengthening low pressure area. As a result some areas may be surprised at the heavy snowfall rates as well as higher accumulations. White out conditions are possible under these snowfall bands with blizzard like conditions on the table.

With all these factors on the table here are my preliminary forecast amounts for cities across the area.
Toronto:12-20cm *WSW and lake enhancement possible*
Hamilton/Burligton:15-25cm *WSW and lake enhancements possible*
Ottawa/Gatineau: 5-15cm
Montreal:15-25cm *WSW possible*
Quebec City:8-15cm
Guelph/Kitchener/Waterloo: 10-20cm *WSW possible*
Windsor/Sarnia: 10-20cm
Barrie: 2-8cm
Parry Sound: trace-5cm
Newmarket: 10-20cm *WSW possible*

Tropical Forcing Supports Eastern trough, Storminess

Strong convection is developing around the date line which supports 3 major changes in the synoptic weather pattern. 1) It supports a strong trough over the aleutian islands and a storm track which is supports by the 6-10 day means on both the ECMWF and GFS

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2) A further east storm track causing more apps runners/ miller b storm tracks as opposed to GLC in the 6-10 and day period. This type of track is likely to pan out with the 26-20th storm threat with two LP centres. In the 11-15 day period more miller a/ miller b storm are likely.

3) A stronger, more robust sub-tropical jet stream will cause stronger southern branch features and thus the development of larger storms further east with more opportunities for downstream phasing to take place.

Take note of the Convection developing around the date line which is strengthening the STJ that extends eastwards to mexico.


OLR anomalies negative east to the mexican coast:

This flare up of convection is being enhanced by the warm water E and NE of new guinea:

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Long Range Outlook: Rex Block Possible

Models are indicating the setup of a potential rex block along the eastern seaboard with the passage of fridays storm. The GFS is allowing this to move out fairly quickly which i suspect is too fast if this type of block does indeed set up. These blocks are never forecasted well by the modelling so any modelling suggesting a warm pattern to end off the month is probably wrong. The european weeklies support this type of pattern which would drive the cold air across the yukon, northern B.C and alaska SE under the strong block to the north. If this occurs with the snowpack building behinds fridays system the cold air will stay in place for a while and the storminess will shift further east favouring apps runners, and east coast snowstorms. 

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8-10 day height anomalies from the GFS and ECMWF:

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6-10 day 850mb temperature anomalies:

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Major Winter Storm Expected For Ontario and Quebec

Winter Weather Forecast Discussion:A significant storm is expected to move into eastern canada from the american midwest by thursday night causing major impacts across southern and eastern ontario as well as quebec. The arrival of this storm will fall just in time for christmas and is expected to dump copious amounts of snow across ontario and quebec increasing white christmas chances significantly. A mixed bad of precipitation will be a threat as well especially across southern and eastern ontario where temperatures will hover around the freezing mark for several hours. The first band of precipitation will move through southern ontario ahead of the cold front late thursday night with an initial burst of wet snow before the precipitation changes over to mainly rain or a mix with ice pellets across the area. This will occur as the low strengthens pulling in warm air out in advance of the cold front. This is typical of very strong low pressure systems which tend to pull warm air into there centers. This is a sign that precipitation is not weakening too much even as occlusion takes place. As the low nears occlusion early friday morning, this changeover to rain will stay very short lived with cold air plunging in from the NW behind the cold front. This will change any backend precipitation back over to a wet snow across southern ontario. Remember that any precipitation west of the cold front will be lighter and more convective in nature meaning short, heavy bursts as opposed to long duration bands. These bands will look very spread out on radar as the deformation band stalls out over michigan and slowly weaken. Heavy bursts of snow will continue throughout the day on friday with a widespread 2-5cm event is expected across southern ontario not including the lake effect snow that will follow friday night into saturday. Across eastern ontario this storm will be a different animal as precipitation arrives by early morning friday with 850mb and 925mb temperatures below freezing which is supportive of frozen precipitation. This is supported by both ecmwf and GFS model guidance. This will promote a mostly snow event for ottawa/gatineau with surface temperatures around 0C. The initial band ahead of the cold front will be very heavy precipitation probably in the form of snow across the ottawa, cornwall and montreal areas. I believe that ottawa is a fairly safe bet in terms of being cold enough for snow but montreal gets a little trickier as an easterly flow will promote warm air advection. There may be some front end mixing but the majority of the event stays as snow across montreal and cornwall. I am expecting an all snow event from trois rivieres northeast to quebec city. By the afternoon hours on friday the upper level trough will go negatively tilted allowing a secondary low to form. The heavy moisture plume will continue across eastern ontario and quebec as 700mb vertical velocity values go off the chart in these bands. This very strong secondary has the chance to create white out conditions across the ottawa, montreal, cornwall, brockville and kingston areas. By this time the cold front will have passed the area allowing for all snow to continue falling with even more supportive boundary layer temperatures. The highest risk with this storm are 850 and 925mb temperatures which will hover around the freezing mark especially in areas along the 401 in eastern ontario and southern quebec. The precipitation will be heavy, so it will all depend on what side of the 0c line you are on to determine if its white out conditions or a wash out with more mixing. Future model guidance may chance exactly where this sets up(50km shifts possible) but models are in good agreement currently. Right now i feel confident that this low is strong enough to pull in plenty of cold air and mixing will be short-lived. As the secondary forms the isobars will tighten across southern ontario promoting additional snowfall on the backside of the secondary area of low pressure. The low will begin to pull away late friday evening allowing precipitation to tone down as the cold air ushers in from the NW.

Here are my preliminary forecast amounts which i will update 24 hours before the event and are subject to change:

GTA north of the 401: 5-15cm of snow including lake effect snow (between thursday night and saturday night). Brief period of rain/ice pellets friday morning
Toronto st clair to the 401: 3-10cm+ of snow including lake effect
Toronto downtown: trace-7cm of snow including lake effect
Barrie: 5-10cm not including LES, brief period of mixing before the change over
Parry Sound: 7-15cm of snow, brief period of mixing before changeover
Cornwall: 10-20cm of snow, front end mixing before radiational cooling allows change over
Ottawa: 20-30cm possible, mostly snow *winter storm warnings likely*
Montreal: 15-25cm of snow, some front end mixing before radiational cooling takes effect *winter storm warnings likely*
Kingston: 10-20cm of snow, right on cusp of larger amounts, shift either way will make big difference
Quebec City: 20-30cm of snow *WSW likely*
Hamilton: trace-5cm of snow including LES
Guelph: 5-15cm of snow including LES
If you have any questions, comments of criticism or would like a forecast for your area feel free to ask away! 

Major LES Outbreak On The Way

Heres my preliminary forecast for this upcoming LES Outbreak

1) There are major model disagreements with regards to duration of this event, with the euro showing a longer lasting event extending into monday night as a secondary low forms across the northeast and moves northwestwards. This allows the flow to turn more northwesterly across ontario as the pressure gradient tightens. The GFS doesn't show a very strong secondary which allows the low to move NE faster therefore limiting the LES activity between friday night into saturday evening. These details will need to be ironed out as we get closer to the event and models come into better agreement. Short range modelling will also make it easier to pinpoint more exact location of said bands, duration as well as strength.

2) A major Lake effect snow outbreak is likely between friday evening and saturday evening across much of southern ontario downwind of lake huron and georgian bay. With a strong low pressure system developing in the u.s midwest, moving NE and stalling across quebec the first major LES outbreak of the season is likely. Behind the low, mid level moisture will be enhanced as a result of the upper low stalling out over central ontario and quebec. 850mb temperatures will crash into the -5 to -10C range causing delta-t values to be in the 13-20C range. Lake effect temperatures are running above normal which adds to the temperature gradient setting up. With very low wind shear values and good alignment of surface, 925, 850 and 700mb wind direction dentritic snow growth is likely. If 850mb temperatures live up to forecasted values snowfall ratios will fall into the 10:1-17:1 range which supports higher accumulations.

2) With a predominantly NW flow event expected off of lake Huron I expect an area from Kincardine south to goderich and east to south huron to endure the worst of this lake effect snow event. I expect a general 10-20cm band to set up with local amounts possibly greater then 30cm especially if the european solution is correct. London will be spared from the worst of the snows with the heaviest activity to the NW of the city. Nonetheless there is still significant agreement that strong Northwesterly winds will be gusting up to 80kph off of lake huron prompting these bands to shift Southeastwards into the london and even strathroy(briefly to start off the event) areas although these bands will stay weaker in nature and will last for a shorter duration of time, limiting snowfall amounts. In this case i believe that london has a far better shot at more significant accumulations as opposed to strathroy(a trace to 5cm) and areas further southwest. 5-10cm+ amounts are possible across the london area with the LES bands which should shift southwards as the event progresses. 

3) Georgian bay bands will be oriented in a NNW direction to start of the event before shifting to a NW direction by late friday night into early saturday morning as the storm system pulls of to the northeast. These bands will continue into the day on saturday extending into the late evening and overnight hours. Areas effected will range from meaford east to collingwood and wasaga beach and south to barrie. Bands will have the potential to extend further south into the innisfil and newmarket areas although i expect lighter accumulations with shorter lasting bands of snow. The orillia area will most likely get in on some actions but i expect most of the LES to be focused from barrie northwestwards. I expect a general 10-20cm event in this band with local amounts exceeding 25cm.

4) I will post an update later this week as the event draws closer and the short range models shed more light on potential accumulations. I will post my forecast map later tonight or tomorrow when i have time to draw up the map but you get the main ideas from my write up. If you have any question feel free to ask away! 

Big Changes On The Way

For anybody doubting this winters performance so far... think again! Strong signals are pointing towards a much colder pattern after the 20th of the month. Stratospheric temperatures are strongly pointing towards a much more favourable pattern for the eastern part of the country with a ridge int he west. With cold anomalies across siberia and eastern europe expect the PV to drop southwards onto our side of the globe. ECMWF stratospheric temp forecasts have high verification scores and it is showing an increase in these temperatures. Right now we are sitting near normal but a ragged spike upwards is likely with this forecast :

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Trough begins to amplify at hour 240 with blocking over the top:

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European Operational lets the cold air loose on our side of the globe with very cold temperatures. This jives well with the stratospheric forecasts but we will see if the models hang on to this as we get closer to the event. We have seen this setup before with the cold anomalies getting pushed further back so we still need to wait and see at this point. Important to note that this is within 10 days so it is out of fantasy range. With ensemble support it's unwise to turn a blind eye at this point to the factors on the table with SSW, retrograding blocks and SOI crashes. I do not want to hype anything here but i am looking at the real life observations on the table which are pointing towards a much more favourable pattern after the 20th.

Kelvin Wave and Stratosphere Analysis

The SOI crash reflects the effects of a kelvin wave moving eastwards in the tropical pacific. This will help to move warmer water into nino 3 and 4 which proceeds eastern cold. This will cause two major changes in the synoptic weather pattern across North America. 1) This will promote convection to fire up along the date line which will cause more trough's to form to the south of the aleutian islands promoting an eastern trough and will hopefully be able to cause more variance in the PNA. 2) As a result of this kelvin wave air is forced to rise through the atmosphere and with lower then normal pressures over the equatorial pacific already this will be enhanced. This movement of air will help to promote an easterly wind in the stratosphere as well as anticyclonic flow which will help to disrupt the polar vortex. The polar vortex is already weakening with the 100mb vortex displaced when compared to the 10mb vortex. This strong kelvin wave combined with the already existent -QBO argues for further weakening of the pre-displaced PV which may cause it to collapse entirely leading to a SSW event. If this does occur, which i suspect it will between now and the end of january a colder heart of winter is a possibility.

Daily SOI values have dropped off considerably which should help revive the el nino, particularly in western regions.

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Notice the already displaced polar vortex:

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Stratospheric anomalies warming and I expect another warm surge which is forecasted to extend into north america promoting more troughiness:

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We all know what these warm anomalies are causing across china and russia, extreme cold! With these anomalies shifting eastwards towards north america, the cold is coming in a significant way as early as next weekend. So if you are doubting this winter, you may want to reconsider because a lot of cold and storminess is coming up for the great lakes,prairies and st lawrence river valley. The storminess comes first leading up until christmas and then i think the cold will establish itself in the east later in the month and into january. Until then in and out cold with very stormy conditions will be the major story across the eastern part of the continent. 

Winter Storm Update Sunday-Monday

A significant winter storm will move into Southern and Eastern Ontario as well as Quebec sunday night into monday. Winter storm watches are up already in parts of quebec and i expect more watches, warnings and advisories to go up later today and tomorrow. A mixed bag of precipitation is to be expected including the potential to see rain, freezing rain, sleet and wet snow. By sunday night we will see an initial push of moderate to heavy precipitation moving directly through the toronto area and extending east towards kingston, brockville, cornwall and through the montreal and ottawa areas later sunday night. This band of precipitation will likely bring an initial burst of snow for ottawa, montreal, and cottage country across southern ontario before a change over to a significant freezing rain event. By the morning hours on monday as the initial batch of precipitation moves out, enough warm air advection will cause the precipitation to change over to all rain or freezing rain for most of the region. Enough cold air should darn as a result of tonights high pressure system which should cool the area to below freezing temperature values. Areas where the most significant freezing rain are possible include the ottawa valley, montreal, cornwall, areas NE of lake ontario along the 401, areas north of the 401 including barrie,orillia, parry sound and northern parts of the GTA where between 0.1" and 0.5" of freezing rain are possible. Confidence is lowest in the city of toronto where the dividing line looks to set up between significant freezing rain, snow and sleet and just plain rain. This will be a tough forecast to make but right now i am thinking an initial burst of sleet and freezing rain but not a long lasting event south of the 401. This is due to past experience with these events where precipitation has trouble changing over in these types of events with marginal surface and 850mb temps. North of the 401 can be a different story with more cold air hanging on allowing for more significant icing. Drivers are urged to take caution and should make travel plans accordingly especially if you do not have snow tires on yet. A combination of low visibility and icy roads will make travelling a huge problem along the 401 corridor sunday after 2pm through monday morning. With that being said these are the potential risks/look for's in tomorrows storm forecast:
1) With surface temps colder then 850mb/ 925mb temperatures, freezing rain will be very likely in areas where surface temperatures can stay at or below 0C. If this is not the case before the event and the surface high does not deliver as much cold air as currently expected less freezing rain will occur across the area. This may occur from kingston and SW along lake ontario if surface temperatures do not cool down enough.
2) With intense upwards motion moving through the area evaporational cooling will be able to cool the parcel of air in areas under heavy precipitation bands. Where these bands set up will be the area effected by significant freezing rain and sleet bands.
With all of these factors in place I am confident in saying that there will be a significant icing event setting up across parts of ontario and quebec as the dynamics are definitely there. It is a question of where and how much at this point! These are my preliminary accumulation forecasts and may have to be tweaked based on short range model output or nowcasting especially due to the variety of precipitation types and difficult forecast period.
Here is my forecast for several cities across ontario and quebec. If I have missed your area just ask and i will add it into the discussion.

Montreal: 5-10cm+ of snow, change over to 5-10mm of freezing rain
Ottawa: 5-15cm of snow, change over to 5mm of freezing rain. If mid levels warm faster then expect more freezing rain and less snow but a general .5-.6" of QPF is expected.
Toronto downtown: Mostly rain with 2-5mm of freezing rain or sleet possible initially
Toronto St Clair-401: 5-10mm of freezing rain or sleet before a change over to rain is likely
GTA north of the 401- 1-4cm of sleet before a changeover to 5-10mm of freezing rain(amounts may need to get taken up or down depending on temps). Rain showers to end off. *Most Volatile Area*.
Parry sound: 5-10cm of snow
Barrie 2-8cm of snow/sleet, 2-5mm of freezing rain
Quebec City- 7-15cm+ of snow, backend freezing drizzle 

Lake Effect Snow Setup Dec 11-12th

I can see some LES setting up late monday night into tuesday morning after this storm passes through the area. With a NW surface flow as well as low and mid level flow the setup will be there for significant lake effect snows in areas downwind of lake huron and georgian bay. Delta-T values between lake and 850mb temperatures will be in the range of 15-20C. This temperature inversion with limited wind shear values will be conductive for a LES setup. Cold air advection will be enhanced behind the cold front passing through the area because of the late time of day. Right now I see this as a minor set up that will not last as long and setting up in traditional areas that get hit during NW and NNW flow events. The winds will be originated out of the NW for most of the time before a shift to the NNW during the morning hours of tuesday. I expect areas from barrie south to alliston and NW to collingwood to get in on the action off of georgian bay while areas from Goderich to london and south to the lambton shores get hit with the snows off of lake huron. With more favourable upper level dynamics I think we will see stronger bands off of lake huron but with georgian bay water temperatures running above normal bands will be significant there as well. In general i am expecting a pretty minor 2-8cm event that will not last for very long but areas outlined in my forecast map should be prepared for this monday night into tuesday. The GTA may feel a few convective flurries under the passing upper level low but no significant LES is expected.

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Storm Update Dec 10-11

Current thoughts on this storm with regards to the first wave of low pressure. With a low developing in the SW U.S and tracking up into southern ontario I am anticipating a mostly rain event for southern ontario if you live south of georgian bay. Some mixing may be felt on the front side as some cold air presses southwards in contact with the over running precipitation. Models have been trending SE recently especially the GFS and ECMWF model guidance. This may be a signal that some more cold air will get involved causing a longer period of mixed precipitation or snow before a change over to rain and then possibly back end snow again. This is yet to be determined until tomorrows 12 and 18z runs which will have the sampling of the energy moving inland from the pacific ocean. In terms of eastern ontario there might be a different story with more surface cold air holding on as the low moves through. ECMWF and GFS model guidance have been indicating Warm air advection in advance of the LP system in the lower and mid levels of the atmosphere. While this is going on the surface temperatures stay at or below zero with over running precipitation which tells me that freezing rain and sleet can be a concern across eastern ontario, southern quebec and even central ontario. These areas are more prone to CAD and I think we will see this setup with the models under going a potential high east of the LP center. Models are likely over phasing a low that moves up to greenland before our storm moves into the area which closes the window for a significant surface high to build across eastern quebec. I see an initial shot of snow for ottawa and montreal before a changeover to a mix with sleet or freezing rain and then maybe a change over to rain later on. The GFS is more bullish on more frozen precipitation while the euro argues for a shorter period. These details will be ironed out on the weekend as modelling gets better sampled and i have a better idea on the exact track on the LP system. To sum up I see a potentially significant freezing rain/sleet and mixed precipitation event for eastern ontario and southern quebec in a line from parry sound to montreal. A swath of snow will set up in an area north of the Montreal and Ottawa. This swath will include quebec city where precipitation will stay mostly as snow with a 7-15cm+ swath and highest amounts across eastern quebec. Southern Ontario is the lowest confidence right now and model guidance still has to be sorted out with recent SE trends to get a better understanding on precipitation type. Right now i am going with a short period of snow and mixing out in front before a change over to rain and a potential change back to snow to end off the system. Updates to come this weekend and and map will come out on sunday. Feel free to ask any questions you may have that have not been covered in my post. 2m temp and precipitation maps are at or below zero in the corridor I mention which has the potential to see significant freezing rain and sleet. Notice 850mb temperatures are warmer then 0c which allows this to setup.

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Storminess First Then Cold Overwhelms

Pattern will become more active across ontario and quebec with a la nina like pattern already setting up now and an active southeast ridge allowing the storm track to shift up towards the great lakes region. Although it is still too early to tell which particular events will hold which precipitation types the boundary between warm and cold will set up across the great lakes which will allow for storminess and potentially snow depending on how much cold air gets involved. 18z GFS notice the active storm track favoured to be further west with the blocking shifting west which should allow for more cooling to shift east. Overall, this is an active and near normal temperature pattern for the east mid month before the frigid air has a chance to come down later in the month when the pattern promotes it. A -pna has been causing the coldest anomalies to shift into the west but with the frigid air building up across the northwest all we need is a trigger for the floodgates of cold to open up in the east. This will be a slow step down to colder and not a sudden cold snap, keep that in mind! I will take snow over cold any day even if it means a few mixed precipitation events.

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Modelling Should Shift East With 10-11th Storm

I believe the european model guidance is too far west with this storm as the system currently west of japan correlates with an east GLC, OV or Apps runner track in the 6-10 day period which is much more in line with the GFS. Watch for the european and other modelling showing a west-central GLC to shift east.
Surface Map:

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Satellite Picture Shows the storm west of Japan:

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Sudden Stratospheric Warming Event Beginning To Materialize

Current observations are showing a rapid warming of the stratosphere at 70,50 and 30mb which means that the sustained arctic cold will come earlier then expected. We will have to watch this situation continue to evolve but it looks like some cold outbreaks will set up in mid december but nothing sustained and brutal. This stratospheric temperature evolution will help to suppress and cool the troposphere rapidly as the stratosphere warms but there is a ten day lag between a sudden stratospheric warming event and the cold felt at the surface. When this does occur temperatures can be frigid with a crash of the AO. Right now anomalies are slightly above normal but if temps continue to soar like they are now then a SSW event may occur allowing that cold air to charge south at the end of dec/beginning of jan period. If this happens it is a very good sign for a cold january. 

Storm Potential Nov 9-11

There are a few points that i want to make about the upcoming storm around the 11th. 
1) Keep in mind that the euro has been doing better then the GFS lately but it has been flip flopping a lot from west to east in the last few runs with this potential storm
2) GFS appears to be having trouble bundling the energy associated with the southern branch energy as well as energy moving in from the NW associated with the trough. It had the idea of a secondary wave but has now went to a stronger, phased storm with one wave

With this being said i do believe a considerable amount of cold air will be available for this storm to work with and locations on the NW side of the low will get pounded with snow. I also believe that this storm will be strong with pressure in the 980's indicated on the three major models (ecm,gfs and cmc). This may be slightly overdone but this storm should be strong. Track of the storm is the largest uncertainty at the moment in my mind but i believe that the euro will shift east some to come more in line with the GFS but probably not that far east. I will continue to update you as the event gets closer and should have a better idea by tomorrow night hopefully. 
Heres the latest run of the 18z GFS:
186:

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192:

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Total snowfall:

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Long Range Cold Lurking

Analogs are indicating a cold pattern trying to erase the warm anomalies across the east from first week of december. Central u.s averages out above normal due to the extreme positive departures they are currently experiencing.

January will turn out very cold from alaska through the northern plains and great lakes into the east. I believe the teleconnections are moving that way and the stratosphere is beginning to warm at a rapid pace which will force the cold to come down in january. The Pacific SST's are very supportive of this pattern change with convection already firing along the date line which did not occur last winter. Arctic hounds should release in january.


Stratospheric warmth shifting east means bering sea ridge moves west into northeast asia, more troughiness returns to the aleutians as well as japan and a ridge pumps up south of alaska.

Current anomalies:

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Notice the shift east of the warmest anomalies which will drive the trough south of the aleutians where the convection is setting up along the dateline. This breakdown of the omega ridge will allow for a much more favourable pattern across eastern NA:

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Convection firing up south of the same area:

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Notice the switch from current 500mb pattern to 8-10 day pattern and trough developing NW of hawaii. I believe the euro is handling the pattern best.
Current strong bering sea ridge and trough in gulf of alaska with warm and progressive north american pattern:

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Major shift to colder in 8-10 day forecast period and just the beginning of the cold pattern with 70mb temperatures looking the way they are!

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