[Model Output Discussion - Colder but how cold and for how long?]

Come on folks try and stay on topic.Too many one liners which are adding nothing to model discussion and are having to be hidden.

Maybe a bit of perspective we are not even in the Northerly cold air yet and when it comes it's probably going to be the coldest spell so far this Winter.Uppers of between -8c to -10c quite widely,even lower in Scotland.
As for snow then i am not going to repeat what others have said but bear in mind that forecasts from the Met have already changed from a day or so ago and likely will be revised again if new features pop up.

If you are still wanting to moan about this then please use the moans thread and let's keep this thread tidy and on topic.

Thanks all.   

[Model discussion highlights]

Forgive me for the number of images in this post but i thought i would try to give my views on the coming 10 days or so.It's just an overall picture so no micro details just how it looks like the pattern might change-- with supporting data.

To begin i think we can say with some certainty the cold will deepen from Sunday as the Arctic air arrives from the north.We will have to keep an eye on the small low development around Iceland shown around day 4 and how that interacts with the general cold flow across us by then.But after all said and done modeling shows the cold gets to the south coast by Monday.

The other main point is the probable Atlantic approach later next week modeled on the UK T144hrs model.

Just to show that this is very much still on the table but as already been said nothing is certain at that range but to give an idea. of what is likely to come.

Now looking at the combined 850hPa ensemble graph

Cold this coming week but no denying there appears to be a trend upwards beyond .

This, shall i say less cold period, has been spoken about as the mjo enters a warmer phase before forecasted to move into a more favourable area for a return to blocking later.

Looking above at the Stratosphere the spv is currently expected to split into 2 centres up to mid-level in the coming few days before reforming in week 2.We can see these 2 centres over Siberia and Canada ,which enables the current Greenland area ridging of heights

These from gfs latest and yesterdays ecm both showing the same trend.

 

 

As can be seen the gfs images are a top to bottom profile and show what Amy Butler called the pair of trousers on the split image.The Ecm image is for 100hPa level,.Both sets do show the vortex reforming which seem to imprint down to our level.This would support the upwards trend in temperatures with a probably return of the westerlies at least for a short while.

The change towards showing on the day 10 ensemble 500hPa mean anomalies.

The pattern moving north as heights over the pole start to drain away.

So the hope is that in the next week or so we will see some snow either from minor disturbances or a battleground event from the south west which may become the main feature as it fights it's way up the country as a mild pattern tries to take over.The uncertainty is how far north this will establish and of course for how long.

Plenty of interest going forward i reckon. 

 

 

Original post: https://community.netweather.tv/topic/99760-model-output-discussion-colder-but-how-cold-and-for-how-long/?do=findComment&comment=5006980

[Model Output Discussion - Colder but how cold and for how long?]

Forgive me for the number of images in this post but i thought i would try to give my views on the coming 10 days or so.It's just an overall picture so no micro details just how it looks like the pattern might change-- with supporting data.

To begin i think we can say with some certainty the cold will deepen from Sunday as the Arctic air arrives from the north.We will have to keep an eye on the small low development around Iceland shown around day 4 and how that interacts with the general cold flow across us by then.But after all said and done modeling shows the cold gets to the south coast by Monday.

The other main point is the probable Atlantic approach later next week modeled on the UK T144hrs model.

Just to show that this is very much still on the table but as already been said nothing is certain at that range but to give an idea. of what is likely to come.

Now looking at the combined 850hPa ensemble graph

Cold this coming week but no denying there appears to be a trend upwards beyond .

This, shall i say less cold period, has been spoken about as the mjo enters a warmer phase before forecasted to move into a more favourable area for a return to blocking later.

Looking above at the Stratosphere the spv is currently expected to split into 2 centres up to mid-level in the coming few days before reforming in week 2.We can see these 2 centres over Siberia and Canada ,which enables the current Greenland area ridging of heights

These from gfs latest and yesterdays ecm both showing the same trend.

 

 

As can be seen the gfs images are a top to bottom profile and show what Amy Butler called the pair of trousers on the split image.The Ecm image is for 100hPa level,.Both sets do show the vortex reforming which seem to imprint down to our level.This would support the upwards trend in temperatures with a probably return of the westerlies at least for a short while.

The change towards showing on the day 10 ensemble 500hPa mean anomalies.

The pattern moving north as heights over the pole start to drain away.

So the hope is that in the next week or so we will see some snow either from minor disturbances or a battleground event from the south west which may become the main feature as it fights it's way up the country as a mild pattern tries to take over.The uncertainty is how far north this will establish and of course for how long.

Plenty of interest going forward i reckon. 

 

 

[Model Output Discussion - Colder but how cold and for how long?]

2 minutes ago, Hammy79 said:

 

Model discussion only please 

Forgive me this upbeat mood caught me out,although i did touch on the longer range models.

[Model Output Discussion - Colder but how cold and for how long?]

34 minutes ago, nick sussex said:

When was the last time we had a decent cold spell in the heart of winter rather than when we’re chasing the last vestiges of winter and the ever increasing solar energy ? 

As Captain Picard says . Make it so ! 

 

As old as i am Nick i can't help feeling this anticipation looking at the prospects of a long cold spell. ie.2 weeks plus.They are not common these days but given all the latest information within the excellent posts by our telecon experts and the longer term charts showing a blocked February then it's hard not to be optimistic for the rest of Winter.

Mmmm  just a thought 1947 didn't really get going until later in January,surely we won't get anything that severe now can we? 

[Model discussion highlights]

Two faxs for Saturday.First is from yesterdays 12z and the second is from the overnight met run,the latest at t84hrs.

 

We can see little step forwards with the high retrogressing, setting us up nicely for the Arctic northerly hitting from Sunday.Cold front approaching Scotland already on that.

These are the ones to follow in the next few days for any developments that will be forecasted  in the flow ,and i dare say there could well be some disturbances heading south in that.

 

Original post: https://community.netweather.tv/topic/99760-model-output-discussion-colder-but-how-cold-and-for-how-long/?do=findComment&comment=5005028

[Model Output Discussion - Colder but how cold and for how long?]

Two faxs for Saturday.First is from yesterdays 12z and the second is from the overnight met run,the latest at t84hrs.

 

We can see little step forwards with the high retrogressing, setting us up nicely for the Arctic northerly hitting from Sunday.Cold front approaching Scotland already on that.

These are the ones to follow in the next few days for any developments that will be forecasted  in the flow ,and i dare say there could well be some disturbances heading south in that.

 

[Model Output Discussion - Colder but how cold and for how long?]

11 minutes ago, TEITS said:

No sadly it isn't and I would of loved to experienced it. Still have the great 1978 blizzard as my first memory. I envy your break in the Cairngorms as i've never been further N than Newcastle!

Much better 06Z with the GH extending further S.

 

No it's no 63 Dave but your point about surface cold under quite modest cold uppers is correct.

I recorded daily weather obs as a school boy during that Winter and still have the diary.The prolonged snow cover for 63 Days was a big factor in keeping it cold at the surface combined with the Atlantic shutdown much of the Winter.

Meanwhile here and now which ever way the operational runs plot the path to next week we arrive at the same result.Cold to the south coast by Monday and a within a day or so an approach from the Atlantic still with the prospects of snow fall where the boundary shows up.

The pattern beyond continues to evolve but the main theme is the jet staying south and a weak Atlantic.

[Model discussion highlights]

Looking at next week on gefs anomalies.We can see the cold air has moved well south into the UK by,yes,15th so right on schedule.

The second and third images the 850s and mean sea level pressure anomalies for day 10-- the end of next week(uk/Europe view),

  

In spite of the ups and downs in the differing operational runs this Wintry pattern continues to be shown.There looks to be some real snowy interest next week,but where will this be is to be decided nearer the time.

 

 

 

 

Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5003964

[Model discussion highlights]

Now the dust is settling on the 12zs i think the overall picture remains of a cold Arctic flow heading south from Sunday followed later by Atlantic lows approaching from the south west from around next mid-week but with cold air in place.

This sets us up for one,maybe 2 battleground snow events later next week.The areas affected to be decided at much closer range but events like this usually affect quite a wide band of the country as they move in.Sometimes they bring in some milder air later or they can stall and even retreat if the cold wins out.

After so many poor Winters from a cold and snow pov let's relish what's in front of us,these synoptics do not appear that frequently.

Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5003898

[Model Output Discussion - Into 2024]

Looking at next week on gefs anomalies.We can see the cold air has moved well south into the UK by,yes,15th so right on schedule.

The second and third images the 850s and mean sea level pressure anomalies for day 10-- the end of next week(uk/Europe view),

  

In spite of the ups and downs in the differing operational runs this Wintry pattern continues to be shown.There looks to be some real snowy interest next week,but where will this be is to be decided nearer the time.

 

 

 

 

[Model Output Discussion - Into 2024]

Now the dust is settling on the 12zs i think the overall picture remains of a cold Arctic flow heading south from Sunday followed later by Atlantic lows approaching from the south west from around next mid-week but with cold air in place.

This sets us up for one,maybe 2 battleground snow events later next week.The areas affected to be decided at much closer range but events like this usually affect quite a wide band of the country as they move in.Sometimes they bring in some milder air later or they can stall and even retreat if the cold wins out.

After so many poor Winters from a cold and snow pov let's relish what's in front of us,these synoptics do not appear that frequently.

[Model Output Discussion - Into 2024]

12 minutes ago, sheikhy said:

Scrap what i said few mins ago and go with what i said 35 mins ago which was the ecm was gona be a beast of a run!!!thats exactly what is in the end!!what a comeback!!!

Whichever route the models take we seem destined  to get the cold in .Ecm also shows a battleground just a bit further north before cold wins out.

Great model viewing with snow chances because of the boundary close to the UK.Cold is good of course but without snow it's almost like bacon without the egg. 

[Model Output Discussion - Into 2024]

No more on this North v South back and forth please.

It's derailing the thread and causing the team to hide the posts.

There are other threads for general chat.

Now back to model discussion please.

Thanks.

[Model Output Discussion - Into 2024]

Those that want more than cold and dry then something along the lines of gfs battleground snow will likely please the eye.This is something that has been suggested in the gefs.

It is high risk that some milder air will get in further south but that's the risk to get a decent fall of snow.If we can get a re-building of the block then the cold may not leave for long.

[Model Output Discussion - Into 2024]

It looks like we have some exciting model charts to come during the next couple of weeks especially if looking for cold and later snowy weather.

Current conditions show the cold easterly is now established as we can see from the temperatures and uppers coming from a very  cold continent.Generally a drier week to come but some snow showers already showing for a few areas and this risk especially further south continues until tomorrow.

 

 

We have 3/4 days before the change over to the well advertised retrogressing high ,underway from Friday.

Pretty good agreement now that we get sufficient ridging north west to eventually see the colder air return from the north,again on time around 15th.

Solid overnight  mean 850hPa anomalies ensembles  for day 10 showing the cold blocking established with Greenland heights and the Scandinavian trough to the north east extending into Europe.By this time the Arctic cold is over the UK.

 

Where we go from there looks interesting,some later ensemble guidance shows the Atlantic moving in from the south west which may well result in a battleground snow event somewhere across the uk.

For now despite the recent differences in operational outputs we seem to be honing in on this change so steady as she goes with plenty for coldies to look forward to.

 

 

[Model Output Discussion - Into 2024]

6 minutes ago, LRD said:

EC46

Good for this week and next

Week of 22 Jan is a complete flip to mild with high anomalies to our south

Rest of run toys with ideas of high anomalies being to our west and/or NW. But the signal isn't quite as robust as it has been. No signal for scandi heights, which is a shame

Overall more good than bad for UK cold but it's a bit 'meh' compared to what it has been showing previously

Later gefs going with an Atlantic approach from the south west.

Too soon to know if we get a battleground snow event.Could be interesting if the block proves stronger.

[Model Output Discussion - Into 2024]

Well the cold spell is now underway as the easterly picks up bringing quite cold uppers  within the next couple of days ,so we are underway.

As can be expected the later frames of each operational model still show some differences but overall the pattern from the end of the week continues to evolve as shown in the continuing ensemble guidance.That being the heights retrogressing towards Greenland from Friday so importantly  this move is now within the short timeframe. 

We have had a few  ups and downs within the runs over recent days showing northern heights ebbing and flowing  but the Arctic region is always a very tricky area to model.

Despite the varying solutions offered by day 10 they all bring the cold in from the north/north east by the 15th,so we are counting down steadily as we change over from the continental easterly to something from the Arctic next week.

So far reasons to be optimistic that we will be heading into week 2 of the cold spell,perhaps with a better chance of snow in an unstable Arctic airmass.

[Model Output Discussion - Into 2024]

Please keep on topic people.

Some bickering posts about who might get snow have been hidden.

Please use the Winter chat threads for this type of discussion

 

Thanks.

[Model discussion highlights]

The GFS operational runs earlier continue to give us the jitters.The difference with them compared to the others starts with a poor attempt at the second amplification day 7/8,the 00z run being the flattest.At least the 06run was better,hopefully it will move to the others again later as we get into near time.

The Gefs and Eps mean anomalies continue to be rock solid at day 10 and counting down to the ridging of heights towards Greenland.

 

What is also reassuring is the mean troughing underneath supporting the heights to the north.In essence no real change to the pattern although i am sure as Tamara said the high may wobble around.

Meanwhile i have been daily following current conditions further east in Europe  and its showing the real cold creeping west day by day.

 

As we have seen from the short term modeling it's on it.s way here from the weekend so we are on the verge now of a colder and drier few days.We now wait to see whether  the Greenland/Iceland heights or whatever we call  them can build in such a way to usher some of that vortex to our north east this way.

Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=4996319

[Model Output Discussion - Into 2024]

Let's keep on model discussion please all.

Any further discussions on the Met O or BBC outlooks please post over to here where the last few have gone.

Thanks.

 

[Model Output Discussion - Into 2024]

The GFS operational runs earlier continue to give us the jitters.The difference with them compared to the others starts with a poor attempt at the second amplification day 7/8,the 00z run being the flattest.At least the 06run was better,hopefully it will move to the others again later as we get into near time.

The Gefs and Eps mean anomalies continue to be rock solid at day 10 and counting down to the ridging of heights towards Greenland.

 

What is also reassuring is the mean troughing underneath supporting the heights to the north.In essence no real change to the pattern although i am sure as Tamara said the high may wobble around.

Meanwhile i have been daily following current conditions further east in Europe  and its showing the real cold creeping west day by day.

 

As we have seen from the short term modeling it's on it.s way here from the weekend so we are on the verge now of a colder and drier few days.We now wait to see whether  the Greenland/Iceland heights or whatever we call  them can build in such a way to usher some of that vortex to our north east this way.

[Model Output Discussion - Into 2024]

I don't think we have seen so much data come together to support the trend to a notable cold spell.

Everything from weakening zonal winds in the Stratosphere to all the operational runs supported by the ensembles are all pointing in this direction.

Hopefully I haven't jinxed it but is quite remarkable to see this level of support.

[Model Output Discussion - Into 2024]

My word what a set of 12zs so far.

The cold easterly now showing is a bonus so would expect those 2m temperatures to go even lower than first thought than would have under a UK high.It wouldn't need much of an upgrade to induce some snow showers but that is for nearer the time.

The overall pattern towards Greenland heights continues to countdown and now within 10 days and counting.Ens. mean anomalies have been pretty solid on this.

W are looking at a pretty significant cold spell now,easterly to north/northeasterly.A classic solid -AO/-NAO pattern lasting for 2 weeks minimum if this trend continues.

Come on ECM let's have a full house this evening.  

[Model Output Discussion - Into 2024]

Please some of you quit with the one liners which add no model discussion.

I think one or two need to step back, take a few breaths and think about what you are posting.

Come on guys the guidelines are clear to see.