Eagle Eye

To be fair, I don't even want the cold that much unless it comes with snow as I either want to be able to have a snowball fight or be able to go outside in a t-shirt. Thunderstorm has been my main weather preference ever since I stopped being scared of it and thats less likely to be affected negatively by what us humans are doing to the planet. Anyway, I'll see myself out for now, got some penguins to walk (they stayed behind after the cold last week and have acclimatised to the SE climate well).

Alright sure. Doesn't make anything I said I my post wrong. The cards were being dealt and less and less impressive, doesn't mean we need to be negative about it, we've just got to take what we get here and it's as simple as that. Taking the youth perspective and I didn't see those great old Winters, in fact I didn't realise get to see 2010 all that well. Yet I still enjoy the 'little' amounts of snow I get because I have to enjoy it otherwise I'll be stressed and sad most of the time because my natural state of mood is to be sad and anxious. Every post I feel that Ive said something wrong and that I'm really 'unintelligent' so my positivity about the weather is because I love it and as well as that it keeps me going so no one is going to take me being positive about Meteorology away from me.

Don't focus on what you could have had focus in what you've already got . Personally, I know others may disagree but this has been my favourite Winter so far since I've joined here and the amout of negativity here is amazing because we're going to have to take from what we've got. Anyone who reads my posts know I prefer to drink from the glass that's half full rather than being negative, just my personal view. Just because we haven't seen amazing historic looking Winters in the last few Years doesn't mean we shouldn't enjoy what we've got. We've got to take the cards we've been dealt.

Isn't that better than nothing though? That's been my point here, at least we're in with a fair shout.

We could however look on the bright side here. We're starting this from a state of a possible Greenland high, a -VE AO that's taking a while to recover and multiple previous wave trains scattering energy downstream. These wave trains will take a while to mix out both their meridional wind anomalies back to just being zonal even in a zonal Trop-Strat connecting pattern surely? Hence why I think we will probably end up zonal around mid January but before that we're still in with some chances.

AAM rebound (Green line) more pronounced than last run . Not as much as I wanted and nowhere near November status but still good that a full blown zonal AAM doesn't look too likely soon. Any Trop connect may not be majorly significant either as we're still in a pattern with a lot of unnatural thermal wave transfer so I don't think roaring zonals are likely till mid January (although it does depend on other circumstances now so it's possible but I don't think the most likely solution).

I noted it yesterday that the 'tail loop' of an Atmospheric River could link up with cold and dump a LOT of snow somewhere in the UK but it depends exactly where it takes place. I think you can see where it does on that ECM .

Small rebound of AAM taking place now as I suspected earlier this morning. Like I said somewhere in that mess of a post (I wrote most of it at 2AM so it's structure is interestingto say the least), I don't think it'll have too much effect but watch out in case the mountain torque rebound is stronger than before. Right now it's too early to tell. Not much to add right now, waiting for the GFS GWO forecast to come out later...

Seeing as this thread's quiet now (and I have definitely not been writing this for 3 hours, talking to Olivia and all that, distractions you know)... The Atmospheric River(AR) event that takes place across the North Atlantic over the next few days looks to happen I'm two phases (or may two separate AR's). First of note is the first wave rapidly approaching Iberia associated with that long elongation of water transport that moves up and dumps Iberia with a lot of precipitation. It's the back of these that are of note to me though because they are relatively cool and moist compared to the first part of the AR (although that still has the moisture) and as I like to call it now, the loopback feed if timed right can mix in with the colder air coming down from the North(ish) as well and bring potentially a lot of snow to Northern and Scottish areas. Potentially further south depending on how the loopback eventually evolves. Beyond that wee that second wave forming through the mid Atlantic feed and we can see that on the precipitation totals fairly strong just off the coast of Florida and we may want to see how that evolves as well. I think it's pretty clear that the Eastern wandering divergent velocity means that from the initial stages and the fact that it seems to be moving quite quickly, the MJO looks to be more progressive and maybe amplified than previously forecasts (like I thought it would, not to brag just a lucky guess)from a few days ago. Suggesting better timing with phase 5/6/7 going into January so we may some renewed downstream blocking around Greenland or Scandinavia depending on how the wave train evolves. Hence the whole EC46keeping the -VE AO pattern in hold. It's a possibility before I think the pattern should collapse by mid January but it depends on how we see the AAM and MJO eventually evolve what happens before that. We may never see the unstable inertia pattern collapse of course but I just find that highly unlikely. The MJO follows on from the VP and is slightly better than the previous runs although it's still only phase 4 that we see as the most amplified. A good trend emerging to amplify phases 4-6/7 further on the forecasts (especially 5,6 and 7) but I think we still want that little extra kick. It's a good background signal to have and better than phases 2 and 3. Phases 6 and 7 having higher support of a -VE NAO in composites and all that stuff. It's clear that the zonal wind has recovered and is going to recover further over the area of 180-120W and so the East Asian Jet Extension (EAJE) is fully into place with a possible energy scattering event that may help us or hinder us down the line. This may see a more zonal favoured longer-term or it could also distribute energy and work with the MJO to form another blocking going into January week 1/2 timeframe as my MJO notes also said, certainly interesting long-term and not just a definite zonal forecast. It could also set up a mid-term Californian AR which doesn't have much effects downstream in my experience but I haven't experienced many knowingly to be fair. The upper troposphere meridional wind also supporting that shorter term Greenland blocking potential (45W) considering the weaker zonal wind but until it actually comes to pass we can't count out the fact that the other models may be correct in that it doesn't form quite so quickly/quite so well so we'll just have to see what happens with this. Onto the GWO and it's clearly not as amplified into a +VE state than most of November but looking at the forecast there might be a slight rebound associated with a +VE mountain torque over the coming days and if they are more amplified than the GFS forecasts we may see a return to a slight +VE state compared to the slight -VE state we seem to be in right now. At this amplification it doesn't really matter though and instead other background signals look to be the main forecasting tools going forward. Clearly the ocean-atmospheric connect still not properly showing itself and so the MJO is likely to have a fairly large effect so be on the lookout for phases 6 and 7 especially until the AAM becomes amplified either way. Then continue to look for those phases still but with varying degrees of desperation for those phases . So what do some of these words and phrases actually mean: I've picked out a few with some of my or others explanations from before My explanations: " Unstable inertia - Inertia is when it keeps it's existing state unless acted upon by another object. Hence unstable inertia is the transfer of energy is between it's existing state and the 'disturbance'. This is a very basic view at both though and unstable inertia involves a lot more than that. -VE just means negative (hence, +VE means positive) Some basics on Atmospheric Angular Momentum (AAM) A few shortened words as well: AMB - Angular Momentum Budget AAM - Atmospheric Angular Momentum MT(mountain torque) GWT(gravity wave torque) FT(frictional torque) If AMB increases in the atmosphere it must have been transferred from another source since AMB is always conserved. The sources for AMB are from the Earth, the Oceans and the Atmosphere. One major aspect in affecting AAM are torques. A torque is the rotational force in the atmosphere. The 3 main torques affecting the atmosphere are: Mountain torque (MT) - The turning force applied with the effect of pressure systems on mountains. Frictional torque (FT) - Boundary layer dynamics. Gravity wave torque (GWT) - Subgrid (local) torque, upward movement and downward movement to do with the buoyancy. If there is a net westerly surface wind, the atmosphere speeds up the Earth's rotation and transfers angular momentum to the earth and so there is a net decrease in AAM. The reverse happens with a net easterly wind Global MT anomalies are constructed by sypnotic waves that scatter energy across Asia and North America. These sypnotic waves trap the SLP anomaly and push them towards the south. Driven south and east of mountains. Sypnotic wave centres amplify aloft. " Away from my definitions now Madden-Julian Oscillation (MJO) (Met Office) - "The Madden-Julian Oscillation is characterised by an eastward spread of large regions of enhanced and suppressed tropical rainfall, mainly observed over the Indian and Pacific Ocean." MJO phases (Met Office) - "When the MJO is in its active phase over Indonesia and the West Pacific, it tends to drive a negative North Atlantic Oscillation (NAO) 2 to 3 weeks later. A positive NAO index tends to be preceded by phase 3 and 4 of the MJO, which brings milder and wetter weather across the UK. A negative NAO index tends to be preceded by phase 6 and 7, which influences a ‘blocked’ weather pattern and is often associated with colder and drier weather across the UK. The timescale of the MJO having an influence on North Atlantic weather regimes is usually 10 to 12 days." North Atlantic Oscillation (NAO) (Met Office) - "Positive NAO phase - Winds from the west dominate, bringing with them warm air, while the position of the jet stream enables stronger and more frequent storms to travel across the Atlantic Negative NAO phase - Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms." Artic Oscillation(AO) (Climate Prediction Centre) - "The daily AO index is constructed by projecting the daily (00Z) 1000mb height anomalies poleward of 20°N onto the loading pattern of the AO. " The loading pattern is just the normal pattern for the time of year to put it basically. Atmospheric River (I say AR) (NOAA) - "Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow." Global Wind Oscillation (GWO) (a NOAA paper on it by Klaus Weickmann and Edward Berry) - https://psl.noaa.gov/map/clim/wb08_final.pdf Anyway, back to my thoughts for the future... So pretty much my thoughts for now are that it's a possibility that's on the cards that we could see a fairly substantial Greenland blocking going into later this week and onwards associated with some sort of zonal wave train but beyond that there is so much more difference. This one should bring cold somewhere in Great Britain even if the Greenland blocking doesn't form and if it does it could connect up with an Atmospheric River to dump a lot of snowfall somewhere depending on the timing I think eventually we could see another renewed Greenland blocking as long as we keep the pattern away from a large zonal state (which I think would have to mainly be powered by the AAM dipping quite deeply -VE after connecting with the La Nina base state) sometime in early(ish) January. So a fair few cold chances long-term and mid term I would think and compared to recent years we take that. There needs be some caution not thrown into the wind as we simply don't really know how energy scattering events will happen in the future if their related torque events haven't happened yet and so wave trains that bring us into a zonal pattern cannot be ruled out. As well as that the -VE NAO isn't a guarantee of cold to be long lasting and it could be west based as a basic example. The EAJE could also connect up with the PNA(Pacific/North American Pattern, another pattern that doesn't directly affect us but I think it's an alright indicator of possible colder air when it's amplified away from neutral but it depends on the pattern) and sort of hijack our weather as well, I think it's a possibility that over time if it keeps being over extended we could see it's downstream effects 'phase out' the Atlantic -VE zonal repeating pattern. Though it can still interact with the MJO fairly well in my opinion to just about distribute the energy right as long as timing is done well which seems to be getting better run by run with a more progressive and amplified MJO phase 6/7 pattern possibly taking effect. The thermal Eddy's 'retracting' due to the loss of AAM doesn't seem to have happened as quickly as I had initially thought a week or so ago (possibly longer). This is shown in a propped up -VE AO phase and so supports the fact that a loss of AAM does not necessarily mean that northern blocking has to go if you can hold the Eddy's in place with little events and if the loss of AAM is fairly minimal then the 'retreat' does not really seem to happen. This has sort of helped my mind thinking things through as to my post this fine morning. We could see these Eddy's 'retract' quite quickly but I don't see much sign of that unless a quick Strat-Trop downwards connecting forcing the Trop to go largely zonal but I think the models initially over-did that and now are trying to bring it back down. As seen by the connect only slightly adding to the +VE zonal forcing on the Troposphere compared to what I've seen on previous runs. This sort of "Saving" us potentially, for now though. Original post: https://community.netweather.tv/topic/98132-model-output-discussion-the-run-up-to-christmas/?do=findComment&comment=4774485

Seeing as this thread's quiet now (and I have definitely not been writing this for 3 hours, talking to Olivia and all that, distractions you know)... The Atmospheric River(AR) event that takes place across the North Atlantic over the next few days looks to happen I'm two phases (or may two separate AR's). First of note is the first wave rapidly approaching Iberia associated with that long elongation of water transport that moves up and dumps Iberia with a lot of precipitation. It's the back of these that are of note to me though because they are relatively cool and moist compared to the first part of the AR (although that still has the moisture) and as I like to call it now, the loopback feed if timed right can mix in with the colder air coming down from the North(ish) as well and bring potentially a lot of snow to Northern and Scottish areas. Potentially further south depending on how the loopback eventually evolves. Beyond that wee that second wave forming through the mid Atlantic feed and we can see that on the precipitation totals fairly strong just off the coast of Florida and we may want to see how that evolves as well. I think it's pretty clear that the Eastern wandering divergent velocity means that from the initial stages and the fact that it seems to be moving quite quickly, the MJO looks to be more progressive and maybe amplified than previously forecasts (like I thought it would, not to brag just a lucky guess)from a few days ago. Suggesting better timing with phase 5/6/7 going into January so we may some renewed downstream blocking around Greenland or Scandinavia depending on how the wave train evolves. Hence the whole EC46keeping the -VE AO pattern in hold. It's a possibility before I think the pattern should collapse by mid January but it depends on how we see the AAM and MJO eventually evolve what happens before that. We may never see the unstable inertia pattern collapse of course but I just find that highly unlikely. The MJO follows on from the VP and is slightly better than the previous runs although it's still only phase 4 that we see as the most amplified. A good trend emerging to amplify phases 4-6/7 further on the forecasts (especially 5,6 and 7) but I think we still want that little extra kick. It's a good background signal to have and better than phases 2 and 3. Phases 6 and 7 having higher support of a -VE NAO in composites and all that stuff. It's clear that the zonal wind has recovered and is going to recover further over the area of 180-120W and so the East Asian Jet Extension (EAJE) is fully into place with a possible energy scattering event that may help us or hinder us down the line. This may see a more zonal favoured longer-term or it could also distribute energy and work with the MJO to form another blocking going into January week 1/2 timeframe as my MJO notes also said, certainly interesting long-term and not just a definite zonal forecast. It could also set up a mid-term Californian AR which doesn't have much effects downstream in my experience but I haven't experienced many knowingly to be fair. The upper troposphere meridional wind also supporting that shorter term Greenland blocking potential (45W) considering the weaker zonal wind but until it actually comes to pass we can't count out the fact that the other models may be correct in that it doesn't form quite so quickly/quite so well so we'll just have to see what happens with this. Onto the GWO and it's clearly not as amplified into a +VE state than most of November but looking at the forecast there might be a slight rebound associated with a +VE mountain torque over the coming days and if they are more amplified than the GFS forecasts we may see a return to a slight +VE state compared to the slight -VE state we seem to be in right now. At this amplification it doesn't really matter though and instead other background signals look to be the main forecasting tools going forward. Clearly the ocean-atmospheric connect still not properly showing itself and so the MJO is likely to have a fairly large effect so be on the lookout for phases 6 and 7 especially until the AAM becomes amplified either way. Then continue to look for those phases still but with varying degrees of desperation for those phases . So what do some of these words and phrases actually mean: I've picked out a few with some of my or others explanations from before My explanations: " Unstable inertia - Inertia is when it keeps it's existing state unless acted upon by another object. Hence unstable inertia is the transfer of energy is between it's existing state and the 'disturbance'. This is a very basic view at both though and unstable inertia involves a lot more than that. -VE just means negative (hence, +VE means positive) Some basics on Atmospheric Angular Momentum (AAM) A few shortened words as well: AMB - Angular Momentum Budget AAM - Atmospheric Angular Momentum MT(mountain torque) GWT(gravity wave torque) FT(frictional torque) If AMB increases in the atmosphere it must have been transferred from another source since AMB is always conserved. The sources for AMB are from the Earth, the Oceans and the Atmosphere. One major aspect in affecting AAM are torques. A torque is the rotational force in the atmosphere. The 3 main torques affecting the atmosphere are: Mountain torque (MT) - The turning force applied with the effect of pressure systems on mountains. Frictional torque (FT) - Boundary layer dynamics. Gravity wave torque (GWT) - Subgrid (local) torque, upward movement and downward movement to do with the buoyancy. If there is a net westerly surface wind, the atmosphere speeds up the Earth's rotation and transfers angular momentum to the earth and so there is a net decrease in AAM. The reverse happens with a net easterly wind Global MT anomalies are constructed by sypnotic waves that scatter energy across Asia and North America. These sypnotic waves trap the SLP anomaly and push them towards the south. Driven south and east of mountains. Sypnotic wave centres amplify aloft. " Away from my definitions now Madden-Julian Oscillation (MJO) (Met Office) - "The Madden-Julian Oscillation is characterised by an eastward spread of large regions of enhanced and suppressed tropical rainfall, mainly observed over the Indian and Pacific Ocean." MJO phases (Met Office) - "When the MJO is in its active phase over Indonesia and the West Pacific, it tends to drive a negative North Atlantic Oscillation (NAO) 2 to 3 weeks later. A positive NAO index tends to be preceded by phase 3 and 4 of the MJO, which brings milder and wetter weather across the UK. A negative NAO index tends to be preceded by phase 6 and 7, which influences a ‘blocked’ weather pattern and is often associated with colder and drier weather across the UK. The timescale of the MJO having an influence on North Atlantic weather regimes is usually 10 to 12 days." North Atlantic Oscillation (NAO) (Met Office) - "Positive NAO phase - Winds from the west dominate, bringing with them warm air, while the position of the jet stream enables stronger and more frequent storms to travel across the Atlantic Negative NAO phase - Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms." Artic Oscillation(AO) (Climate Prediction Centre) - "The daily AO index is constructed by projecting the daily (00Z) 1000mb height anomalies poleward of 20°N onto the loading pattern of the AO. " The loading pattern is just the normal pattern for the time of year to put it basically. Atmospheric River (I say AR) (NOAA) - "Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow." Global Wind Oscillation (GWO) (a NOAA paper on it by Klaus Weickmann and Edward Berry) - https://psl.noaa.gov/map/clim/wb08_final.pdf Anyway, back to my thoughts for the future... So pretty much my thoughts for now are that it's a possibility that's on the cards that we could see a fairly substantial Greenland blocking going into later this week and onwards associated with some sort of zonal wave train but beyond that there is so much more difference. This one should bring cold somewhere in Great Britain even if the Greenland blocking doesn't form and if it does it could connect up with an Atmospheric River to dump a lot of snowfall somewhere depending on the timing I think eventually we could see another renewed Greenland blocking as long as we keep the pattern away from a large zonal state (which I think would have to mainly be powered by the AAM dipping quite deeply -VE after connecting with the La Nina base state) sometime in early(ish) January. So a fair few cold chances long-term and mid term I would think and compared to recent years we take that. There needs be some caution not thrown into the wind as we simply don't really know how energy scattering events will happen in the future if their related torque events haven't happened yet and so wave trains that bring us into a zonal pattern cannot be ruled out. As well as that the -VE NAO isn't a guarantee of cold to be long lasting and it could be west based as a basic example. The EAJE could also connect up with the PNA(Pacific/North American Pattern, another pattern that doesn't directly affect us but I think it's an alright indicator of possible colder air when it's amplified away from neutral but it depends on the pattern) and sort of hijack our weather as well, I think it's a possibility that over time if it keeps being over extended we could see it's downstream effects 'phase out' the Atlantic -VE zonal repeating pattern. Though it can still interact with the MJO fairly well in my opinion to just about distribute the energy right as long as timing is done well which seems to be getting better run by run with a more progressive and amplified MJO phase 6/7 pattern possibly taking effect. The thermal Eddy's 'retracting' due to the loss of AAM doesn't seem to have happened as quickly as I had initially thought a week or so ago (possibly longer). This is shown in a propped up -VE AO phase and so supports the fact that a loss of AAM does not necessarily mean that northern blocking has to go if you can hold the Eddy's in place with little events and if the loss of AAM is fairly minimal then the 'retreat' does not really seem to happen. This has sort of helped my mind thinking things through as to my post this fine morning. We could see these Eddy's 'retract' quite quickly but I don't see much sign of that unless a quick Strat-Trop downwards connecting forcing the Trop to go largely zonal but I think the models initially over-did that and now are trying to bring it back down. As seen by the connect only slightly adding to the +VE zonal forcing on the Troposphere compared to what I've seen on previous runs. This sort of "Saving" us potentially, for now though.

I think the connect with the Trop and Strat vortex amplifying both into largely zonal patterns was an over-estimate based off pretty unfounded Ocean-Atmosphere coupling. I'm not saying they can't I just don't think that it will, we should stay largely around average and not dip too deep into the -VE AAM for now and some +VE torque events could cause a rebound pr two setting off unstable inertial patterns propping up unstable Rossby Wave thermal transfer. What this means is that, Rossby Waves should be more likely to propagate vertically and they impart a slight Easterly forcing where they propagate so as long as we keep getting these mini rebounds into +VE AAM (or even better hold an unstable inertia pattern in +VE AAM) then the Trop and Strat shouldn't go into the distance of large +VE zonal patterns. Eventually, I would imagine the unstable inertia stops propping itself up but when and how is anybody guess. For all we know, we could technically keep this going on all Winter however unlikely. The more favoured solution is for a better first half of Winter and that's my thoughts, December through mid January for now remain the beat times for a proper cold pattern but let's see how this all evolves. Original post: https://community.netweather.tv/topic/98132-model-output-discussion-the-run-up-to-christmas/?do=findComment&comment=4774286

I think the connect with the Trop and Strat vortex amplifying both into largely zonal patterns was an over-estimate based off pretty unfounded Ocean-Atmosphere coupling. I'm not saying they can't I just don't think that it will, we should stay largely around average and not dip too deep into the -VE AAM for now and some +VE torque events could cause a rebound pr two setting off unstable inertial patterns propping up unstable Rossby Wave thermal transfer. What this means is that, Rossby Waves should be more likely to propagate vertically and they impart a slight Easterly forcing where they propagate so as long as we keep getting these mini rebounds into +VE AAM (or even better hold an unstable inertia pattern in +VE AAM) then the Trop and Strat shouldn't go into the distance of large +VE zonal patterns. Eventually, I would imagine the unstable inertia stops propping itself up but when and how is anybody guess. For all we know, we could technically keep this going on all Winter however unlikely. The more favoured solution is for a better first half of Winter and that's my thoughts, December through mid January for now remain the beat times for a proper cold pattern but let's see how this all evolves.

Just a short post for now: Alright so, I've noted an Atmospheric River a lot today but what can it's effects be. Let's have a look at a fairly major one in California last year: Ours won't nearly be as strong as that but if we can get the cold strong enough for around Christmas time and the back edge of the AR can time itself with that we could find somewhere with a near Christmas (or maybe on Christmas) decent snowfall. Our AR hasn't gotten that much vertically integrated water transporting with it but that doesn't mean it can't bring a fair amount of precipitation with it and the back edge of these AR's tend to be colder so if we can time it will we may potentially see a lot of snowfall somewhere but surely nowhere near as much as the one last December. So, I'll keep monitoring the AR and you can monitor how the cold moves .

Well, the strong water vapor transport horizontally sourced from the Atlantic should bring cold, dry air on the back edge of it. Considering this is Winter and the long sourced Atmospheric River(AR) and despite the large moisture stream, how much moisture rich it'll be by the time it reaches here is difficult to tell. According to the models it transitions most of the moisture fairly well though. The cold and relatively dry air packet should connect to the back edge of the AR but notice that a little bit of the AR will extend back into the colder air and something like that in an AR if the air is cold enough could potentially dump a lot of snow somewhere. Note that the AR seems to come in waves that each act like their own little AR with the first one here, the first AR and WAA packet of air. Hence we see the south getting a little bit warmer than average at initial AR landing time ()although the Midlands and further North can still be cold with the AR predicted to move further South each run. Also, the air is quite cold in the first place so WAA will only mix that out sightly and it doesn't look too strong. Then we see the WAA move further West as the zonal packet associated(ish) with the AR also moves further West and hence the cold, dry air sources itself towards us and there's a decent elongation of the AR into Scotland. In this situation, we could see a lot of snow dumped in Scotland and maybe the North if it looked like this closer to time. Original post: https://community.netweather.tv/topic/98132-model-output-discussion-the-run-up-to-christmas/?do=findComment&comment=4774118

Well, the strong water vapor transport horizontally sourced from the Atlantic should bring cold, dry air on the back edge of it. Considering this is Winter and the long sourced Atmospheric River(AR) and despite the large moisture stream, how much moisture rich it'll be by the time it reaches here is difficult to tell. According to the models it transitions most of the moisture fairly well though. The cold and relatively dry air packet should connect to the back edge of the AR but notice that a little bit of the AR will extend back into the colder air and something like that in an AR if the air is cold enough could potentially dump a lot of snow somewhere. Note that the AR seems to come in waves that each act like their own little AR with the first one here, the first AR and WAA packet of air. Hence we see the south getting a little bit warmer than average at initial AR landing time ()although the Midlands and further North can still be cold with the AR predicted to move further South each run. Also, the air is quite cold in the first place so WAA will only mix that out sightly and it doesn't look too strong. Then we see the WAA move further West as the zonal packet associated(ish) with the AR also moves further West and hence the cold, dry air sources itself towards us and there's a decent elongation of the AR into Scotland. In this situation, we could see a lot of snow dumped in Scotland and maybe the North if it looked like this closer to time.

Whilst wave after wave of ridiculously anomalously warm air across Europe with possible date records to be broken and maybe some areas around 15°C above average, we're I'm with a chance of fairly decent cold. The interaction of the energy scattering downstream of the EAJR and EAJE have meant that the wave train interacts with that area of warm air Africa drawing up some quite mild air and given the exact angle of attack it can be quite moist air given the moisture right off the coast of Africa. This seems a feed from the Atmospheric River streaming across the Atlantic. So away from southern Europe (more dry African air), it could look like what a typical zonal Winter looks to us for parts of Europe (including us actually). This Atmospheric River having trended slightly further south recently I would say and Paul Blight's tweet from a few days ago noted, I'd say that we're probably in with the best chance of snow and cold especially in the North of the country compared to about 80% of Europe. I would take that compared to recent Winters. Not looking at Europe with envy as much. Mild and wet for Europe and possibly cold and wet for us but how cold it gets determines what that precipitation falls as, its quite exciting in my opinion. Naturally, you would expect the exposed coastal areas in Iberia and the West of our Country to have the best chance of precipitation, so if we can get it to cool down slightly more progressively there, then they might be in the game too but I'm not sure how well an Atmospheric River event works when we bring in dry air more from the North(ish) if it trends too far South. Europe Scandinavia - Bouts of cold and warmth, similar snow chance to us (although they usually get a lot so slightly above ours but that's pretty normal). Iberia - Mild and wet (that's right, they've taken our weather). UK and Ireland - Looks cold and wet but how cold and timing? Original post: https://community.netweather.tv/topic/98132-model-output-discussion-the-run-up-to-christmas/?do=findComment&comment=4773914

Now imagine this Atmospheric River keeping itself strong and mixing with cold air from let's say, the East(ish). You've then got yourself a GFS run on steroids.

The first meridional packet slowly moves East but the main worry is how the second one develops and hopefully it'll be more progressive. It renewed the Euro ridge and we see some slight WAA hence the cold doesn't hang around for long. Beyond that though, notice the formation of that 'packet' around 60W moving for 45W and the formation of the Greenland high properly as shown on the last few runs associated with that. For longer term cold prospects that'll probably be our main chance. If the 0-30E 2nd meridional packet is more progressive then we may not see the renewed WAA quite so strongly and the cold hangs along for longer but it's hard to tell whether it will be or not. Lots of interest going into the future and don't get annoyed if the cold can't get set in for a long term, sometimes, the weather just throws a few hundred spanners into the works. Anyway, it should just delay the inevitable as long as the Greenland block stays in place as the latest GFS shows. GFS throwing out some build up to the New Year happiness at the moment, hope it gains more support from the other models.

Alright so I'm not even going to take the CFS AAM forecast into account considering it doesn't even start in the right AAM phase , or maybe the analysis is wrong. Merry Christmas CFS .

Whilst wave after wave of ridiculously anomalously warm air across Europe with possible date records to be broken and maybe some areas around 15°C above average, we're I'm with a chance of fairly decent cold. The interaction of the energy scattering downstream of the EAJR and EAJE have meant that the wave train interacts with that area of warm air Africa drawing up some quite mild air and given the exact angle of attack it can be quite moist air given the moisture right off the coast of Africa. This seems a feed from the Atmospheric River streaming across the Atlantic. So away from southern Europe (more dry African air), it could look like what a typical zonal Winter looks to us for parts of Europe (including us actually). This Atmospheric River having trended slightly further south recently I would say and Paul Blight's tweet from a few days ago noted, I'd say that we're probably in with the best chance of snow and cold especially in the North of the country compared to about 80% of Europe. I would take that compared to recent Winters. Not looking at Europe with envy as much. Mild and wet for Europe and possibly cold and wet for us but how cold it gets determines what that precipitation falls as, its quite exciting in my opinion. Naturally, you would expect the exposed coastal areas in Iberia and the West of our Country to have the best chance of precipitation, so if we can get it to cool down slightly more progressively there, then they might be in the game too but I'm not sure how well an Atmospheric River event works when we bring in dry air more from the North(ish) if it trends too far South. Europe Scandinavia - Bouts of cold and warmth, similar snow chance to us (although they usually get a lot so slightly above ours but that's pretty normal). Iberia - Mild and wet (that's right, they've taken our weather). UK and Ireland - Looks cold and wet but how cold and timing?

@MATTWOLVES @offerman You two are great people who don't deserve to go through what you're going through and I hope somehow, someway things get better for you. I know Matt a bit better (but still only the least of it) and I cannot tell you how much of a great person he is, who doesn't deserve anything like what he's gone through. I think everyone on here should realise how much it takes to make someone like him. If we take a look at every 18Z run since the 13th let's see if we can find a trend: There is very little in the way of a trend there but it's clear that the North and Scotland are in the mix on most of the runs and except for the 1st one which was at day 12 only a few hundred miles south (which at this range is a possibility of course) and the midlands would be in play. In the south I wouldn't get too excited yet, we've only had 2 of the 6 in our favour but that doesn't mean we can't keep an eye on how it evolves from here. What do the ensembles say? No major trend but sort of the trend is for the cold to be taken further south through the UK and the Euro/Scandi/Eurasian blocking seems to be slightly further south. I think we could be in for a fairly cold Christmas day (yes I know these are the 850's) and there may be some conductive uppers for some snow as well. Don't know what's gotten some people down on here, maybe they think that the rain (according to radar it's pretty much all rain now) is pathetic fallacy for something or another. I'm slightly less confident of my long-term Greenland block long-term forecast because it hung a bit on the AAM quickly rebounding and so phase 5 of the MJO helps us more (based off my unsupported hypothesis). Whereas here, the GWO suggests that AAM won't rise that well (green line is the forecast) and looks like it'll probably stay fairly lodged in the weak -VE state and act slightly Nina-Esque but at this amplification it shouldn't be too much of a worry, it just won't help build the blocks for a Greenland block. Once/if after that small rebound happens we will probably end up with a more zonal pattern as the AAM slowly falls and these wave trains get less 'helpful' but I won't worry about that for now as that's unlikely to be too strong till we get to Teleconnection FI of 2047 early-mid January which should surely eventually wane the Greenland blocking if it does form but like I said I wouldn't worry about it for now. But there's two sides to every 100-sided coin () and it's a possibility that energy is scattered fairly well for a Greenland block development despite the AAM and sort of the MJO signal. 45W is where you look at to find Greenland although how the zonal wind anomalies interact when it's 20-30N with the meridional winds depends on the circumstances. A lot of confusion on the models but we've got a decent chance for a decent snowfall 'event' from Christmas onwards for the next few days it's just how the models track it from here that's going to be the problem because the flip flops keep flip flopping. Then beyond that there is the signal for a potential Greenland blocking but to be more confident in it I would want a slightly more progressive MJO and AAM recovery to be better, otherwise I'm still fairly 50/50 as to how this could evolve. It's very interesting though and the conflicting signals make it nightmare forecasting so don't worry if you're confused. The flip-flopping and crisscrossing probably means that even the Mets are finding it difficult to come up with a highly accurate forecast let alone any of us. So don't worry if you don't really have much of an idea what's going to happen on Christmas day and onwards, we can blame it on the flip-flops the models have put on. Original post: https://community.netweather.tv/topic/98087-model-output-discussion-the-cold-has-arrived/?do=findComment&comment=4773573

@MATTWOLVES @offerman You two are great people who don't deserve to go through what you're going through and I hope somehow, someway things get better for you. I know Matt a bit better (but still only the least of it) and I cannot tell you how much of a great person he is, who doesn't deserve anything like what he's gone through. I think everyone on here should realise how much it takes to make someone like him. If we take a look at every 18Z run since the 13th let's see if we can find a trend: There is very little in the way of a trend there but it's clear that the North and Scotland are in the mix on most of the runs and except for the 1st one which was at day 12 only a few hundred miles south (which at this range is a possibility of course) and the midlands would be in play. In the south I wouldn't get too excited yet, we've only had 2 of the 6 in our favour but that doesn't mean we can't keep an eye on how it evolves from here. What do the ensembles say? No major trend but sort of the trend is for the cold to be taken further south through the UK and the Euro/Scandi/Eurasian blocking seems to be slightly further south. I think we could be in for a fairly cold Christmas day (yes I know these are the 850's) and there may be some conductive uppers for some snow as well. Don't know what's gotten some people down on here, maybe they think that the rain (according to radar it's pretty much all rain now) is pathetic fallacy for something or another. I'm slightly less confident of my long-term Greenland block long-term forecast because it hung a bit on the AAM quickly rebounding and so phase 5 of the MJO helps us more (based off my unsupported hypothesis). Whereas here, the GWO suggests that AAM won't rise that well (green line is the forecast) and looks like it'll probably stay fairly lodged in the weak -VE state and act slightly Nina-Esque but at this amplification it shouldn't be too much of a worry, it just won't help build the blocks for a Greenland block. Once/if after that small rebound happens we will probably end up with a more zonal pattern as the AAM slowly falls and these wave trains get less 'helpful' but I won't worry about that for now as that's unlikely to be too strong till we get to Teleconnection FI of 2047 early-mid January which should surely eventually wane the Greenland blocking if it does form but like I said I wouldn't worry about it for now. But there's two sides to every 100-sided coin () and it's a possibility that energy is scattered fairly well for a Greenland block development despite the AAM and sort of the MJO signal. 45W is where you look at to find Greenland although how the zonal wind anomalies interact when it's 20-30N with the meridional winds depends on the circumstances. A lot of confusion on the models but we've got a decent chance for a decent snowfall 'event' from Christmas onwards for the next few days it's just how the models track it from here that's going to be the problem because the flip flops keep flip flopping. Then beyond that there is the signal for a potential Greenland blocking but to be more confident in it I would want a slightly more progressive MJO and AAM recovery to be better, otherwise I'm still fairly 50/50 as to how this could evolve. It's very interesting though and the conflicting signals make it nightmare forecasting so don't worry if you're confused. The flip-flopping and crisscrossing probably means that even the Mets are finding it difficult to come up with a highly accurate forecast let alone any of us. So don't worry if you don't really have much of an idea what's going to happen on Christmas day and onwards, we can blame it on the flip-flops the models have put on.

I've seen it before that the GFS underplayed the amplification of the MJO for the first phase 6/7 and eventual cold spell fairly significantly so I would argue that it could do it again (could being the important word here).

Still a lot of arguments on here even though Paul told you to stop not that long ago. I understand you are passionate in your beliefs but you lot are adults and I'm a child at least I have an excuse . It's nearly Christmas and you seem to be feeling very little Christmas spirit, we don't want the mods to have to work really hard just to keep us in line when we're capable of thinking before posting. Anyway, the MJO looks to be progressing nicely into more neutral and then -VE NAO chance phases by next week onwards so late December onwards may be the next best time for anything other than a cold dip (which can also spring surprises) although timing which I have noted is important before is hard to tell. Linking up fairly well with the progression of the zonal winds as I sort of noted earlier.

Sorry I'm not great at that sort of thing as a long term forecast like that would be almost impossible, at that point it comes down to little dynamics that can't be forecasted well yet. A Scandi high could be helpful but in this situation with a developing reaction to the Eurasian -VE zonal pattern and therefore the +VE feedback forming its very unlikely so I'll be chasing the Greenland high for now.