Catacol

I think it would be hard to find a better setup than that about to unravel. Only solar is out of ideal kilter but on its own, irrelevant. -MJO amplified and back in the west pacific in the final third of this month - GLAAM has remained high, further surge expected. +EAMT? - Vortex is weakened and possibly about to split - Scandy has been cold since the autumn. There is cold nearby to tap into - eQBO firmly embedded, ENSO Nino with +IOD now done and dusted These are the keys for me. I’m not moving from what I said a few days ago. Cold for a long time.. Original post: https://community.netweather.tv/topic/99760-model-output-discussion-colder-but-how-cold-and-for-how-long/?do=findComment&comment=5005813

I think it would be hard to find a better setup than that about to unravel. Only solar is out of ideal kilter but on its own, irrelevant. -MJO amplified and back in the west pacific in the final third of this month - GLAAM has remained high, further surge expected. +EAMT? - Vortex is weakened and possibly about to split - Scandy has been cold since the autumn. There is cold nearby to tap into - eQBO firmly embedded, ENSO Nino with +IOD now done and dusted These are the keys for me. I’m not moving from what I said a few days ago. Cold for a long time..

12z runs are verifying better than 00z at the moment, suggesting that amplified solutions are coming up trumps. Fits the GWO orbit.

Haha - now that I hadn't seen. That's even better than the CFS (which I said couldn't be any better....so scrap that comment.) Just look at the contrast mid atlantic between greeny and the jet directly to the south? If ever there was a sign of a southerly tracking jet, full of moisture, and a cold block in situ then this is it. Gallas!

Just ok?? - it literally couldn't be any better though the gloss is taken off by the fact it is the CFS. I prefer the JMA monthly - that won't be too far away.

Quite excellent. I was going to post something later of a similar but much less well explained and detailed nature. I won't bother now. The drivers that have lined up to produce this first amplification phase and are lined up to produce the second surge of amplification next week are going nowhere anytime soon. As I posted before, MJO progression is clear and well timed. I think week 22-29 January will be the least cold section of the next month or so but GLAAM has remained high with little damage caused by the ping back of relative AAM progression. We are shortly going to see another surge that will set us up beautifully, given lag, for the end of the month and on into February. But this is a poor summary compared to the post above. Read that and wrestle with its contents. As to next week - no change. Snow will be in the mix whether those who enjoy posting the least favourable interpretation of current signals and output like it or not.

this. Are we not able yet to step back from the ever variable context of ever changing runs and just enjoy each cold day, with its individual character, safe in the knowledge that there is a wealth of evidence pointing towards an extended period of cool/cold/very cold options with convective showers, steamers and frontal events all in the hat, waiting to be drawn? There is absolutely no point whatsoever dissecting every run. In % terms I think we can agree that the majority of NWP evidence over the last week has indicate a cold pattern setting in. Is there anything to be gained straining to see if and when a breakdown is coming and for how many days? Nope. 2018 lasted a fortnight on and off. Maybe we won’t reach the peaks of that special spell - we will only know that when looking backwards at the end of the season - but I think the general wintry pattern this time around has greater longevity potential. Polish your streetlights, clean the windows, find the gloves and snow boots and cross fingers for the luck that is needed as the cherry on top.

UKMO excellent, GEM not bad. ECM looking very good at 192, longer range to come. And I have returned from work to possibly the greatest MetO text update in many a year. GFS the odd one out this time around and consigned to the naughty step. Loved today. It was sunny, clear and cold. Gritters out and the usual media overhyped top temperature for the day undercut by about 3 degrees. Reckon it didn’t break 2.5 here. It really is game on. Having quite a detailed Met update back the signals I have stuck my neck out for has brightened things further. If only heating oil was a bit cheaper I’d be grinning ear to ear.

ECM has just thrown out the most potentially snow charts across the UK from days 8-10 that we have seen since 2018. I'm in a rush - I dont have time to read the many pages of comments, though I will predict that some are very happy at these and some are bemoaning the marginal 850s in the south and sounding the doom-bell. 850 predictions at day 8 are utterly irrelevant. Look for the pattern. Cold trough, channel systems bumping into it. There are snow opportunities likely from both convective shower streams off the north sea as well as cold/warm boundary frontal events. This is about as good as it gets. Happy days says this pig in sh*t. Enjoy your own day if you can and remember (contrary to my initial post yesterday!) that 12z forecasts are verifying better than 00z at the moment so let's build on this morning's foundation later on. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5002777

A fair point - but I'm not sure the prognosis at the moment has really deviated from the overall shape of things that was probably best expressed by Tamara a couple of her posts ago. We have the wave break now that is being pushed up to high latitude at the end of the week, we then have the cold trough dropping in. We will likely have a slower breakdown from this than the models predict (because observationally models speed up breakdowns than is usually the case once it happens) and then we have - with the less favourable MJO phases and a drop in AAM - an anomaly chart like this to wrestle with: First of all it is a very long way off - but if we take it at face value it reflects the progression of the drivers stated above but does not really give us a scooby as to what the synoptics will be. There is certainly a pressure contrast that is still suggestive of weak -NAO but quite where the cold/warm boundary will sit is very uncertain. Then - looking at the latest GEPS that, to my eye, has been a bit more accurate than GEFS from the 00z run we get this out in the very far reaches of ensemble modelling: High pressure starting to build back into Greenland in line with the Nino background and drivers pointing to renewed momentum and amplification which then ties in with the EC weekly move back towards this: So - some degree of relaxation of the cold was inevitable at the end of next week, but it does look temporary and - in any case - quite where the boundary between the warm and cold air will be is utterly impossible to nail down now. I think the overall pattern as described in that post of Tamara's remains solid. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5002814

A fair point - but I'm not sure the prognosis at the moment has really deviated from the overall shape of things that was probably best expressed by Tamara a couple of her posts ago. We have the wave break now that is being pushed up to high latitude at the end of the week, we then have the cold trough dropping in. We will likely have a slower breakdown from this than the models predict (because observationally models speed up breakdowns than is usually the case once it happens) and then we have - with the less favourable MJO phases and a drop in AAM - an anomaly chart like this to wrestle with: First of all it is a very long way off - but if we take it at face value it reflects the progression of the drivers stated above but does not really give us a scooby as to what the synoptics will be. There is certainly a pressure contrast that is still suggestive of weak -NAO but quite where the cold/warm boundary will sit is very uncertain. Then - looking at the latest GEPS that, to my eye, has been a bit more accurate than GEFS from the 00z run we get this out in the very far reaches of ensemble modelling: High pressure starting to build back into Greenland in line with the Nino background and drivers pointing to renewed momentum and amplification which then ties in with the EC weekly move back towards this: So - some degree of relaxation of the cold was inevitable at the end of next week, but it does look temporary and - in any case - quite where the boundary between the warm and cold air will be is utterly impossible to nail down now. I think the overall pattern as described in that post of Tamara's remains solid.

ECM has just thrown out the most potentially snow charts across the UK from days 8-10 that we have seen since 2018. I'm in a rush - I dont have time to read the many pages of comments, though I will predict that some are very happy at these and some are bemoaning the marginal 850s in the south and sounding the doom-bell. 850 predictions at day 8 are utterly irrelevant. Look for the pattern. Cold trough, channel systems bumping into it. There are snow opportunities likely from both convective shower streams off the north sea as well as cold/warm boundary frontal events. This is about as good as it gets. Happy days says this pig in sh*t. Enjoy your own day if you can and remember (contrary to my initial post yesterday!) that 12z forecasts are verifying better than 00z at the moment so let's build on this morning's foundation later on.

@Met4Cast - roll with the muppetry. It doesn’t matter how many times some folk on here are advised not to jump on every micro detail change at 240h. It still happens despite the solid ongoing signal. If current anticipated synoptics are not good enough then I hate to think how people are going to react in the future to the 85-90% of seasons with more typical patterns. All good. Trough still dropping down the eastern side of a significant block. Good times.

Zoiks. And I was speaking out my ar*e earlier - 12z runs are verifying better than the 00z ones. (Would help if I bothered to check the axis labels properly... ) - which should please those looking at this GFS run who enjoying digging cars out of the snow!

Countdown to @Scott Inghamday is on - now 168 hours away. For those interested, verification stats for 00z runs are quite a bit ahead of the 12z runs at the moment, and when it comes to 168h prediction from 00z runs there is very little between the models at the moment and that includes GEM. Don't diss it! Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5000723

Countdown to @Scott Inghamday is on - now 168 hours away. For those interested, verification stats for 00z runs are quite a bit ahead of the 12z runs at the moment, and when it comes to 168h prediction from 00z runs there is very little between the models at the moment and that includes GEM. Don't diss it!

Bounce back to zero complete. Not too much damage done - still significantly "Nino" as an /ocean/atmosphere coupling and momentum is on the high side still So. The challenge now is to work out just how significant the lagged impacts of the dip will be, timed for week 3 starting 22 Jan. Anyone looking at the EC weeklies can see the change, BUT we are likely to have embedded cold as this flatter influence returns. If we remember back to December as a case study the westerlies came through as expected, but the timeline was put back and the crash was quite a big one. Not so this time, and cold will be significantly stronger. I think the battleground snow scenario for that week will gain traction. Too far out at present to see any evidence in NWP but it will come. Some warming of the overall pattern at that point is inevitable, but I dont think it will last long and we can cross fingers that it may only impact the south. Next rise in frictional/mountain torque will be in the wings and the MJO is forecast to be back in the western pacific soon after 21 Jan by both ECM and BOMM with GFS only a few days behind. So... no change really to the prognosis laid out before. 1. Cool to cold, sometimes very cold this week, mainly anti cyclonic but some snow showers bound to pop up. 2. Cold to very cold, sometimes severe cold? the week after, snow in the mix from both NE and SW potentially. 3. Cool to cold in final week of Jan with battleground snow potential, low pressures deflected south with luck. 4. Amplified into early February - Greenland again? Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5000301

Bounce back to zero complete. Not too much damage done - still significantly "Nino" as an /ocean/atmosphere coupling and momentum is on the high side still So. The challenge now is to work out just how significant the lagged impacts of the dip will be, timed for week 3 starting 22 Jan. Anyone looking at the EC weeklies can see the change, BUT we are likely to have embedded cold as this flatter influence returns. If we remember back to December as a case study the westerlies came through as expected, but the timeline was put back and the crash was quite a big one. Not so this time, and cold will be significantly stronger. I think the battleground snow scenario for that week will gain traction. Too far out at present to see any evidence in NWP but it will come. Some warming of the overall pattern at that point is inevitable, but I dont think it will last long and we can cross fingers that it may only impact the south. Next rise in frictional/mountain torque will be in the wings and the MJO is forecast to be back in the western pacific soon after 21 Jan by both ECM and BOMM with GFS only a few days behind. So... no change really to the prognosis laid out before. 1. Cool to cold, sometimes very cold this week, mainly anti cyclonic but some snow showers bound to pop up. 2. Cold to very cold, sometimes severe cold? the week after, snow in the mix from both NE and SW potentially. 3. Cool to cold in final week of Jan with battleground snow potential, low pressures deflected south with luck. 4. Amplified into early February - Greenland again?

100% yes. Colder conditions start now - as always expected. Shift to even colder as the trough drops in from the NE is from wb 15 Jan - again no change. Background signals still in place, no change. Snow opportunities still in place as per forecasting this spell from inception, and the MetO have not changed their tune either. And yes - these are still the best charts and likely synoptics since 2018 despite the negativity in some posts on this thread. No change.

That is a good point. Hemispheric average is one thing, regional accuracy another and accuracy on particular weather regimes another again. I did once upon a time manage to track down some regional seasonal data that suggested, despite the theoretical increased accuracy of modelling in winter, that actually over the North Atlantic the reverse was true and winter was harder than summer to get right - but cannot remember where I got that from now. I’m not bothered by all the gnashing of teeth in here bemoaning the fact that -12 850s are unlikely to smother the U.K. for a week. I’m happy to see a general pattern that broadly matches the teleconnections and offers real potential and for the extended at that. I must admit, though, that if we get some half decent synoptics in place and then everything waters down once in the reliable that it will force me back towards the conclusion I began to come to a couple of years ago, namely that only a split SSW a la 2018 is likely to produce extremely cold patterns for the U.K. going forward. Damn our changing world - but still plenty of time for the pattern drivers to pull NWP into line and show that a warming troposphere, warming oceans and a cooling stratosphere can still be overpowered.

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about. As I see it taking into account usual U.K. winter synoptics: 850s of 0 = Cool 850s of -4 = Cold (has to be, given at -4 snow is in the mix) 850s of -8 = Very Cold (rare, and snow over rain nearly ever time) 850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!) 850s of -16 = Exceptional Cold (how often in the last 50 years?) On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix. Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4999153

Data is clear. ECM beats GFS hands down at 120h. But at 240h the gap is slight to very slight. At 192 and lower ECM holds the whip hand most of the time - though not all of the time! At 240h they are both valuable.

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about. As I see it taking into account usual U.K. winter synoptics: 850s of 0 = Cool 850s of -4 = Cold (has to be, given at -4 snow is in the mix) 850s of -8 = Very Cold (rare, and snow over rain nearly ever time) 850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!) 850s of -16 = Exceptional Cold (how often in the last 50 years?) On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix. Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential.

Some things never change. It is as though model watchers wake up every morning determined to be gloomy. ECM 240 GFS 240 GEM 240 I'd give my right army for charts like these in any winter. My only comment would be to address the delay issue. Those long in the tooth on watching models know that high pressure is often, if not always, modelled to move faster than actually occurs in practice. So seeing the trough arrive a day or two later fits the observation. No issue with this provided we maintain low pressure to the south and dont see a sub-tropical high resurge. Any signs of this? Well - on the EPS not really at realistic range. Weds 17 and the midnight EPS still have pressure lowered over the continent and yesterday's EPS the same out to 300h. There are too many on here who get the magnifying glass out at 192h+ and see slight shifts as a disaster. There are always going to be shifts - it is absolutely impossible for one complex run produced out of Tb of data to be the same as another and these will sometimes "improve" or "downgrade". But one thing is for sure - getting hung up on 850 spaghetti charts at 192-240h range is 100% guaranteed to drive you nuts. As I said yesterday NWP is hopeless at getting 850s right even within high resolution range, and an 850 spaghetti does not really therefore give you much of an idea of synoptics. Enjoy the ride. This has a long way to run yet - hopefully a very long way to run. Patience, stamina and a very healthy dose of perspective required. Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4999081

Some things never change. It is as though model watchers wake up every morning determined to be gloomy. ECM 240 GFS 240 GEM 240 I'd give my right army for charts like these in any winter. My only comment would be to address the delay issue. Those long in the tooth on watching models know that high pressure is often, if not always, modelled to move faster than actually occurs in practice. So seeing the trough arrive a day or two later fits the observation. No issue with this provided we maintain low pressure to the south and dont see a sub-tropical high resurge. Any signs of this? Well - on the EPS not really at realistic range. Weds 17 and the midnight EPS still have pressure lowered over the continent and yesterday's EPS the same out to 300h. There are too many on here who get the magnifying glass out at 192h+ and see slight shifts as a disaster. There are always going to be shifts - it is absolutely impossible for one complex run produced out of Tb of data to be the same as another and these will sometimes "improve" or "downgrade". But one thing is for sure - getting hung up on 850 spaghetti charts at 192-240h range is 100% guaranteed to drive you nuts. As I said yesterday NWP is hopeless at getting 850s right even within high resolution range, and an 850 spaghetti does not really therefore give you much of an idea of synoptics. Enjoy the ride. This has a long way to run yet - hopefully a very long way to run. Patience, stamina and a very healthy dose of perspective required.