Model Output Discussion - Into Winter

[adamgooner]

A reality check is needed here for anyone pushing the wintry narrative in the lead up to Xmas.

If we put the background drivers to one side for a moment (they are by no means a guarantee of determining the weather and have been wrong many times before) then the current nwp projections are about as bad as they can get for cold /snow fans.  You can spin it any which way you like to argue if this happens…if that happens etc etc and find a straw to clutch to pedal a cold wintry narrative if that’s your weather ideal.

The reality is there is zero northern blocking, the pv has moved from a favourable position to an unfavourable one and much of Europe is trending mild, in our case v mild at times.

Call me a gloom monger or just a realist - cold and snow will not be on the menu this Xmas and imo before the year is out.

On the positive side - the steep trend away from positive wintry charts has been v noticeable, always a chance things can change again…unlikely any time soon though….time for a break from the models me thinks.

[That ECM]

10 minutes ago, andy989 said:

Did it get pushed back? We are talking about the Canadian warming that was progged to happen early December, not the SSW that is progged to happen in January. 

Apologies. Blue has answered. My bad I was thinking ssw.

[northwestsnow]

Well ,time for a break for me ,I'm not in the business of logging on and going straight to 240hrs on GFS/EC searching for scraps,done that far too many times over the years, it just leads to frustration.

Hopefully something better after Xmas but as BA says ,the models now keeping Euro heights for 12 to 16 days,ain't going to be a cold spell with Euro heights..

Fingers crossed some of the background drivers deliver in the long run..

 

 

Edited December 10, 2023 by northwestsnow

[johncam]

1 hour ago, Tidal Wave said:

Indeed, I think some are in denial. There's no doubting the recent trends from the models, as alluded to yesterday by experienced guys on here such as BA. This huge high developing to the south later next week is going to take some shifting and the models look to have been underplaying its influence previously. A drier spell will be much welcomed by many I'm sure, especially with Christmas on the horizon.

Where the high is where I am we will be cloudy and drizzly which is just bloody awful.

[TEITS]

Disappointing model runs but this isn't surprising to me. Some of the previous GFS runs showing a N,ly around xmas were really only glancing blows.

The SLP ensembles  clearly show no sign of any high latitude blocking with the Iceland dropping below 1000mb on Xmas eve. The SLP mean for Oslo, Helsinki hover near 1002mb as a W,ly flow blasts into Scandi.

By the end of next week/weekend the pressure could be at 1040mb for my location.

 

Only glimmer of hope is this high may move W into the following week and may allow some brief colder N/NW,lys. Unlikely to be severe or sustained as the polar flow is likely to be cut off due to a lack of blocking over Greenland.

[kumquat]

Lol if it walks like a Bartlett and talks like a Bartlett.... just a j/k 

[clark3r]

10 minutes ago, TEITS said:

Disappointing model runs but this isn't surprising to me. Some of the previous GFS runs showing a N,ly around xmas were really only glancing blows.

The SLP ensembles  clearly show no sign of any high latitude blocking with the Iceland dropping below 1000mb on Xmas eve. The SLP mean for Oslo, Helsinki hover near 1002mb as a W,ly flow blasts into Scandi.

By the end of next week/weekend the pressure could be at 1040mb for my location.

 

Only glimmer of hope is this high may move W into the following week and may allow some brief colder N/NW,lys. Unlikely to be severe or sustained as the polar flow is likely to be cut off due to a lack of blocking over Greenland.

I would love that chart in high summer!  Least it is not showing wet and stormy 

[MattH]

As I mentioned in a previous post, with some attachments and slides, the outlook is focused on this next MJO passage. There was some caution here as to whether the signal was being over-amplified by tropical cyclone activity and that may still be the case, but the overall trend in model data, as exampled in the two images here, is for the MJO to quickly progress towards the Maritimes and then the W Pacific. Any amplitude through phases 6-7-8, along with a rise in the GWO to higher Nino phases continues to point towards very interesting synoptics further down the line.

Good morning...

I start by highlighting the above first - Since the opening few days of December, the above remains a feature that still needs to occur. While not a surprise there are far too many posts in here already, essentially, saying Christmas won't be cold, or the end of December will be x,y and z - Some need to put the breaks on for a little while...

The evolution ahead (short term) is not a surprise. The more progressive progression to a more cyclonic spell has been well documented for some time and we are seeing that now, the exact reasons for the build of pressure later this coming week, IMO, can't simply be linked to the teleconnections. The reason for the build of pressure, through a couple of stages, is linked to synoptic developments over the USA and the W Atlantic. What is disappointing mind is it is likely to lead to a very mild spell indeed, given the main CoG of the high. While there remains some room for 'give and take' over the position of the high, the GFS is looking too bullish with this build over the UK and a mild/very tropical maritime W-SW flow is likely to dominate the mid-month period as an active westerly flow dominates over the top.

We then look, still, to the period that I've focused on for some time and that being the final third of December - The 20th to the 31st - We continue to see differences in the evolution of the MJO and the associated VP200 signal. As I mentioned back in early December "there was some caution here as to whether the signal was being over-amplified" and we have model differences over this even now. Equally, while this remains a watching brief it is disappointing to see little influence, yet anyway, on the GSDM with the GWO yet to rise, as was suggested, for example.

If we don't see the amplified MJO signal, like the BOM model is suggesting, and we end up with a less significant event then I do believe the output for the Christmas period may well actually evolve like is signalled now, with semi-amplified Atlantic highs that bring brief N or NW'lies, but with more cyclonic events flattening the high as they move over the top and I am leaning more that way now after this being a watching brief - The 'holy grail' of a high amplified MJO passage, large GWO rise and significant impacts are becoming less and less likely with reducing risk of "very interesting synoptics" further down the line.

It does, however, remain a watching brief and to completely rule out the rest of Dec because of recent model runs is, as ever, just daft. Once again December was never meant to be a 'wintry month' and was often progged to be the most +ve NAO month of the winter. We've just had a noteworthy week of cold weather and the outlook is still nothing like it can be at this time of year when a resolute and strong sPV links to the tPV - Those Decembers really can often be written off, but, again that isn't the case this year.

Some adjustments need to be made as the situation continues to evolve - significant or pronounced northern blocking and 'holy grail' winter synoptics through the Christmas period do look less likely, but we still need to see how the current tropical signal evolves and with 2 weeks to go until Christmas, let alone the end of the month, there is still a lot of legs left in this yet.

Cheers, Matt.

[ANYWEATHER]

Looking far into the unreliable from gfs and to a lesser degree the ecm , it's a trend which I've picked up on a good many runs now, is the showstopper for a proper deep cold shot for Christmas are the heights, or high pressure fairly consistently predicted over southern Europe.  We all know that to get proper cold over the uk we need low pressure over southern Europe.  Whist ,I'm not calling anything just yet, I'm afraid the usual green Christmas will be in situ for just about all, but happy for the weather to prove me wrong!

[adamgooner]

23 minutes ago, MattH said:

As I mentioned in a previous post, with some attachments and slides, the outlook is focused on this next MJO passage. There was some caution here as to whether the signal was being over-amplified by tropical cyclone activity and that may still be the case, but the overall trend in model data, as exampled in the two images here, is for the MJO to quickly progress towards the Maritimes and then the W Pacific. Any amplitude through phases 6-7-8, along with a rise in the GWO to higher Nino phases continues to point towards very interesting synoptics further down the line.

Good morning...

I start by highlighting the above first - Since the opening few days of December, the above remains a feature that still needs to occur. While not a surprise there are far too many posts in here already, essentially, saying Christmas won't be cold, or the end of December will be x,y and z - Some need to put the breaks on for a little while...

The evolution ahead (short term) is not a surprise. The more progressive progression to a more cyclonic spell has been well documented for some time and we are seeing that now, the exact reasons for the build of pressure later this coming week, IMO, can't simply be linked to the teleconnections. The reason for the build of pressure, through a couple of stages, is linked to synoptic developments over the USA and the W Atlantic. What is disappointing mind is it is likely to lead to a very mild spell indeed, given the main CoG of the high. While there remains some room for 'give and take' over the position of the high, the GFS is looking too bullish with this build over the UK and a mild/very tropical maritime W-SW flow is likely to dominate the mid-month period as an active westerly flow dominates over the top.

We then look, still, to the period that I've focused on for some time and that being the final third of December - The 20th to the 31st - We continue to see differences in the evolution of the MJO and the associated VP200 signal. As I mentioned back in early December "there was some caution here as to whether the signal was being over-amplified" and we have model differences over this even now. Equally, while this remains a watching brief it is disappointing to see little influence, yet anyway, on the GSDM with the GWO yet to rise, as was suggested, for example.

If we don't see the amplified MJO signal, like the BOM model is suggesting, and we end up with a less significant event then I do believe the output for the Christmas period may well actually evolve like is signalled now, with semi-amplified Atlantic highs that bring brief N or NW'lies, but with more cyclonic events flattening the high as they move over the top and I am leaning more that way now after this being a watching brief - The 'holy grail' of a high amplified MJO passage, large GWO rise and significant impacts are becoming less and less likely with reducing risk of "very interesting synoptics" further down the line.

It does, however, remain a watching brief and to completely rule out the rest of Dec because of recent model runs is, as ever, just daft. Once again December was never meant to be a 'wintry month' and was often progged to be the most +ve NAO month of the winter. We've just had a noteworthy week of cold weather and the outlook is still nothing like it can be at this time of year when a resolute and strong sPV links to the tPV - Those Decembers really can often be written off, but, again that isn't the case this year.

Some adjustments need to be made as the situation continues to evolve - significant or pronounced northern blocking and 'holy grail' winter synoptics through the Christmas period do look less likely, but we still need to see how the current tropical signal evolves and with 2 weeks to go until Christmas, let alone the end of the month, there is still a lot of legs left in this yet.

Cheers, Matt.

Matt, respect your knowledge (far greater than mine) but I do sense you’re seeing what you want to see at the expense of what’s realistic.

You’ve been banging the wintry nirvana projections for around Xmas for several weeks all based on background signals.

You and I know these are never a guarantee- for the less knowledgeable posters and readers on here I think it would be right to at least acknowledge the current nwp has taken a significant step back towards a cold and wintry outcome over recent days.

Your post whilst detailed and informative doesn’t really touch upon anything other than the background signals which many of us are aware of.

The reality is - if we take a broad sweep of all available nwp charts and esembles there is little to latch on to right now, sorry just being a realist here (don’t shoot the messenger).

Edited December 10, 2023 by adamgooner

[AO-]

Good Morning,

 

I have just taken a look at the different members of the GFS00 and I must say that there are no interesting members in the output atm. The coolest members are the ones that put the high a little more North with the axis just in place to get an inversion. When looking at the nhp it is a little different and it seems there are some small changes needed at the beginning in order to get a right setup for cold with Northern blocking at the right place. Yet, it is only december 10th, so we have to wait I guess untill we enter phase 7 of MJO next week. Nevertheless it is disappointing of course.

Edited December 10, 2023 by AO-

[Vikos]

 

in a couple of runs we could be swinging back to colder prospects… who knows. Just don’t get too upset by some “bad” runs. Things can change within a few days, it’s still a chaotic process… 

Edited December 10, 2023 by Vikos

[northwestsnow]

2 minutes ago, AO- said:

Good Morning,

 

I have just taken a look at the different members of the GFS00 and I must say that there are no interesting members in the output atm. The coolest members are the ones that put the high a little more North with the axe just in place to get an inversion. When looking at the nhp it is a little different and it seems there are some small changes needed at the beginning in order to get a right setup for cold with Northern blocking at the right place. Yet, it is only december 10th, so we have to wait I guess untill we enter phase 7 of MJO next week. Nevertheless it is disappointing of course.

Agreed.

I do hope BOM is right with its higher amplitude phases 7/8,I've learned enough to understand the mjo in isolation is not the silver bullet, but it would certainly help trying to break from the strong Atlantic jet stream and PV over Greenland.

All eyes on EC / GFS mjo projections , if we get low amplitude as depicted by these two I think that would be very unfortunate.

 

[johncam]

22 minutes ago, MattH said:

As I mentioned in a previous post, with some attachments and slides, the outlook is focused on this next MJO passage. There was some caution here as to whether the signal was being over-amplified by tropical cyclone activity and that may still be the case, but the overall trend in model data, as exampled in the two images here, is for the MJO to quickly progress towards the Maritimes and then the W Pacific. Any amplitude through phases 6-7-8, along with a rise in the GWO to higher Nino phases continues to point towards very interesting synoptics further down the line.

Good morning...

I start by highlighting the above first - Since the opening few days of December, the above remains a feature that still needs to occur. While not a surprise there are far too many posts in here already, essentially, saying Christmas won't be cold, or the end of December will be x,y and z - Some need to put the breaks on for a little while...

The evolution ahead (short term) is not a surprise. The more progressive progression to a more cyclonic spell has been well documented for some time and we are seeing that now, the exact reasons for the build of pressure later this coming week, IMO, can't simply be linked to the teleconnections. The reason for the build of pressure, through a couple of stages, is linked to synoptic developments over the USA and the W Atlantic. What is disappointing mind is it is likely to lead to a very mild spell indeed, given the main CoG of the high. While there remains some room for 'give and take' over the position of the high, the GFS is looking too bullish with this build over the UK and a mild/very tropical maritime W-SW flow is likely to dominate the mid-month period as an active westerly flow dominates over the top.

We then look, still, to the period that I've focused on for some time and that being the final third of December - The 20th to the 31st - We continue to see differences in the evolution of the MJO and the associated VP200 signal. As I mentioned back in early December "there was some caution here as to whether the signal was being over-amplified" and we have model differences over this even now. Equally, while this remains a watching brief it is disappointing to see little influence, yet anyway, on the GSDM with the GWO yet to rise, as was suggested, for example.

If we don't see the amplified MJO signal, like the BOM model is suggesting, and we end up with a less significant event then I do believe the output for the Christmas period may well actually evolve like is signalled now, with semi-amplified Atlantic highs that bring brief N or NW'lies, but with more cyclonic events flattening the high as they move over the top and I am leaning more that way now after this being a watching brief - The 'holy grail' of a high amplified MJO passage, large GWO rise and significant impacts are becoming less and less likely with reducing risk of "very interesting synoptics" further down the line.

It does, however, remain a watching brief and to completely rule out the rest of Dec because of recent model runs is, as ever, just daft. Once again December was never meant to be a 'wintry month' and was often progged to be the most +ve NAO month of the winter. We've just had a noteworthy week of cold weather and the outlook is still nothing like it can be at this time of year when a resolute and strong sPV links to the tPV - Those Decembers really can often be written off, but, again that isn't the case this year.

Some adjustments need to be made as the situation continues to evolve - significant or pronounced northern blocking and 'holy grail' winter synoptics through the Christmas period do look less likely, but we still need to see how the current tropical signal evolves and with 2 weeks to go until Christmas, let alone the end of the month, there is still a lot of legs left in this yet.

Cheers, Matt.

Thanks Matt , your input is always level headed. What do you think has went wrong from the initial synopsis.

[KTtom]

5 minutes ago, johncam said:

Thanks Matt , your input is always level headed. What do you think has went wrong from the initial synopsis.

I still go back to July when everything was aligned for a settled and very warm August.. it didn't happen! The phrase 'Rock solid science can't be wrong' being used to describe the background signals in mid July. 

Edited December 10, 2023 by KTtom

[northwestsnow]

30 minutes ago, MattH said:

As I mentioned in a previous post, with some attachments and slides, the outlook is focused on this next MJO passage. There was some caution here as to whether the signal was being over-amplified by tropical cyclone activity and that may still be the case, but the overall trend in model data, as exampled in the two images here, is for the MJO to quickly progress towards the Maritimes and then the W Pacific. Any amplitude through phases 6-7-8, along with a rise in the GWO to higher Nino phases continues to point towards very interesting synoptics further down the line.

Good morning...

I start by highlighting the above first - Since the opening few days of December, the above remains a feature that still needs to occur. While not a surprise there are far too many posts in here already, essentially, saying Christmas won't be cold, or the end of December will be x,y and z - Some need to put the breaks on for a little while...

The evolution ahead (short term) is not a surprise. The more progressive progression to a more cyclonic spell has been well documented for some time and we are seeing that now, the exact reasons for the build of pressure later this coming week, IMO, can't simply be linked to the teleconnections. The reason for the build of pressure, through a couple of stages, is linked to synoptic developments over the USA and the W Atlantic. What is disappointing mind is it is likely to lead to a very mild spell indeed, given the main CoG of the high. While there remains some room for 'give and take' over the position of the high, the GFS is looking too bullish with this build over the UK and a mild/very tropical maritime W-SW flow is likely to dominate the mid-month period as an active westerly flow dominates over the top.

We then look, still, to the period that I've focused on for some time and that being the final third of December - The 20th to the 31st - We continue to see differences in the evolution of the MJO and the associated VP200 signal. As I mentioned back in early December "there was some caution here as to whether the signal was being over-amplified" and we have model differences over this even now. Equally, while this remains a watching brief it is disappointing to see little influence, yet anyway, on the GSDM with the GWO yet to rise, as was suggested, for example.

If we don't see the amplified MJO signal, like the BOM model is suggesting, and we end up with a less significant event then I do believe the output for the Christmas period may well actually evolve like is signalled now, with semi-amplified Atlantic highs that bring brief N or NW'lies, but with more cyclonic events flattening the high as they move over the top and I am leaning more that way now after this being a watching brief - The 'holy grail' of a high amplified MJO passage, large GWO rise and significant impacts are becoming less and less likely with reducing risk of "very interesting synoptics" further down the line.

It does, however, remain a watching brief and to completely rule out the rest of Dec because of recent model runs is, as ever, just daft. Once again December was never meant to be a 'wintry month' and was often progged to be the most +ve NAO month of the winter. We've just had a noteworthy week of cold weather and the outlook is still nothing like it can be at this time of year when a resolute and strong sPV links to the tPV - Those Decembers really can often be written off, but, again that isn't the case this year.

Some adjustments need to be made as the situation continues to evolve - significant or pronounced northern blocking and 'holy grail' winter synoptics through the Christmas period do look less likely, but we still need to see how the current tropical signal evolves and with 2 weeks to go until Christmas, let alone the end of the month, there is still a lot of legs left in this yet.

Cheers, Matt.

Pinched from Blue 

Eps mean end of week 2  , the strat  warming is happening  we need  the Trop to play ball !

Edited December 10, 2023 by northwestsnow

[northwestsnow]

Big changes on gfs 6z

0z

[TauntonRoss]

1 minute ago, northwestsnow said:

Big changes on gfs 6z

0z

Yeah so far the GFS looks better until the next run

[feb1991blizzard]

i understand the concern but not complete despondency, this chart is well before expectation, if not weeks before.

[bluearmy]

11 minutes ago, AO- said:

Good Morning,

 

I have just taken a look at the different members of the GFS00 and I must say that there are no interesting members in the output atm. The coolest members are the ones that put the high a little more North with the axe just in place to get an inversion. When looking at the nhp it is a little different and it seems there are some small changes needed at the beginning in order to get a right setup for cold with Northern blocking at the right place. Yet, it is only december 10th, so we have to wait I guess untill we enter phase 7 of MJO next week. Nevertheless it is disappointing of course.

The 51 eps members are in agreement 

it’s only a few cold zonal norwesterly geps members that maintain any hope for a white Xmas based on his mornings runs

but things can change and I’m very open minded to that at the moment 

just a comment on the MJO - the model ens suites generate their expectation of how the atmosphere will evolve over the next fortnight 

the automated MJO forecasts are simply a reflection of those runs - just as the NAO, AO, EPO, etc etc. 

At the moment, the ens (Bom apart) don’t see any MJO amplitude in their runs. The composites we see posted from MJO phases are what we would expect to see post certain phases with some amplitude. So if the modelling has this wrong and there will be higher amplitude then expect the runs to begin to reflect this late on because they will have this higher amplitude in them which should mean they evolve to show more amplification in the Atlantic sector as the runs progress. You can’t have one without the other as many have pointed out. But it isn’t an exact science - phase 7 at a certain amp doesn’t mean a downstream feature is definitive at a a certain place. It’s just an indicator of more propensity for a broad pattern. 

for now, we can hope that the high delivers some seasonal conditions but given where it’s likely to sit I’d expect more gloom than sun and frost!

[Gowon]

7 minutes ago, northwestsnow said:

Big changes on gfs 6z

0z

I thought you was done with checking the models?

[IDO]

The GFS 06z is in broad agreement up to D10 with the 0z, so consistent. The main variation is the axis of the Atlantic high on the 06z, more favourable to some colder air from the north, brief as that is likely to be, but the UK remains on the wrong side of the trough:

06z: 0z: 

Too far away to determine how that Atlantic high will play out, especially as op runs are notorious for overplaying heights at that range.

[That ECM]

1 hour ago, northwestsnow said:

Well ,time for a break for me ,I'm not in the business of logging on and going straight to 240hrs on GFS/EC searching for scraps,done that far too many times over the years, it just leads to frustration.

Hopefully something better after Xmas but as BA says ,the models now keeping Euro heights for 12 to 16 days,ain't going to be a cold spell with Euro heights..

Fingers crossed some of the background drivers deliver in the long run..

 

 

How’s the break going?

[January Snowstorm]

The old reverse psychology trick that everyone is on this morning is working wonders!! The 06z is very different, look at all that cold to our East!! The chase is back  

[TSNWK]

Just now, January Snowstorm said:

The old reverse psychology trick that everyone is on this morning is working wonders!! The 06z is very different, look at all that cold to our East!! The chase is back  

Until 4.00pm