Model output discussion - Into 2021

[Scott Ingham]

3 minutes ago, bluearmy said:

both gfs runs have a runner of sorts ...... ecm had one yesterday ....always a chance of something headed into the base of the trough  (if one exists - both trough and runner!)

 

We aren’t talking about a strongly neg AO showing yet nor atmosphere in reverse - just a stalling of the flow ..... which is evident on those gfs 12z runs with a gentle rise in heights across the polar field 

I feel it has legs the runner/slider/battleground low as slight waning of momentum before the warming starts to take more effect should in theory open a tiny door to atlantic energy just as the westerlies start to grind to a halt.

Thinking logically the balance between how flat and how strong the energy as a consequence is something models will continue to struggle and toy with

[Cold Winter Night]

4 minutes ago, Ventnor Viking said:

It could develop, I personally cant see it happening so quickly within a couple of days and then making it to us. Seems very unlikely. 

If a Scandi/Nova Zembla High is placed right, with good alignment, even that deep Siberian cold can reach even the UK in 4-7 days.

Like @chionomaniac just said, a frigid run hasn't shown up yet, but in this setup, we really can be optimistic.

[Allseasons-Si]

1 minute ago, IDO said:

Looking at the gefs at d8 something is happening and if this is not a rogue suite then it is very interesting. The op seems tame compared to some of the members:

 

I quite like the look of those IDO and the short gefs ens to go along with those

we are seeing good upgrades early on.

[Ice Day]

Excellent set of short GEFS for my location - shows the 'upgrade' in cold in the short-term.

Probably the coldest of the winter so far. 

 

[Scott Ingham]

19 minutes ago, Chiltern_Blizzard said:

Long time watcher of this forum but just signed up...

It does seem to be that these are always 10 + days away. Can I ask ...when do these become a reality? As the models for today, 10 days ago were showing similar...

Were already on day 5/6 of a cold spell buddy. Snow has fallen in several places. Some look to get lucky due to an upgrade in uppers on the easterly and were trying to find consensus on a low dropping due south from the arctic.

Everything has tickled along just as expected with the ssw the final and potentially coldest piece of the jigsaw just coming into view

[Jason H]

3 minutes ago, Allseasons-si said:

I quite like the look of those IDO and the short gefs ens to go along with those

we are seeing good upgrades early on.

Those are definitely getting better.

[Ventnor Viking]

Just now, Cold Winter Night said:

If a Scandi/Nova Zembla High is placed right, with good alignment, even that deep Siberian cold can reach even the UK in 4-7 days.

Like @chionomaniac just said, a frigid run hasn't shown up yet, but in this setup, we really can be optimistic.

I'm not being negative or rude to anyone, just being realistic. It "could" but hasn't and absolutely a frigid run hasn't shown yet so not worth talking about. I think it would be so much easier to discuss what's being presented. So many talk so positively and people get excited about maybes, I just cant. I need to see consistency at a much closer timeframe to become optimistic, been here too many times.  

[bluearmy]

2 minutes ago, Harsh Climate said:

 Yes but there can still be a brief stalling of the atlantic flow during any set-up, doesn't mean it's the precursor to a full SSW event.

Like I believe before this upcoming SSW event takes place I think there will be a brief milder or less cold period. 

Like November 2010 when it's ready I think it will just come in and hit hard was massive northern hemisphere blocking and reverse zonal winds. Just my opinion but these are notoriously slow burners and I don't think it will have any effect on our weather until the end of the month or befrurary.

I've seen SSW forecast in februrary before but never materialised until april/may with fantastic synoptics, all so late lol.

Did anyone say that it was?   In any case, there is currently a full ssw ongoing so not sure what you’re getting at unless you’re referring to a trop response to the confirmed ssw now started via a downwelling wave.  The waves when they come down will show in parts of the pattern reversing in the NH ..... we are merely speaking about the normal west to east momentum losing its oomph. the ssw high up will remove the zonal flow that might normally be expected to feed the trop below. The slow down of zonal flow throughout the atmosphere will be noted from top to bottom - I appreciate that we currently have no idea how any reversal waves may propagate down to the trop ........ 

[Scott Ingham]

4 minutes ago, Allseasons-si said:

I quite like the look of those IDO and the short gefs ens to go along with those

we are seeing good upgrades early on.

Much improved. Nice flattening out of the pattern

[Gregulator]

19 minutes ago, ICE COLD said:

IMBY chart of the day

Thats a better looking chart, just needs to materialise now.

[Allseasons-Si]

3 minutes ago, Scott Ingham said:

Much improved. Nice flattening out of the pattern

Whoah!!!,...dont say that in here lol you will get the place in uproar ha! ha!

you mean the ens are "flat lining" 

Edited January 2, 2021 by Allseasons-si

[Battleground Snow]

3 minutes ago, Ventnor Viking said:

I'm not being negative or rude to anyone, just being realistic. It "could" but hasn't and absolutely a frigid run hasn't shown yet so not worth talking about. I think it would be so much easier to discuss what's being presented. So many talk so positively and people get excited about maybes, I just cant. I need to see consistency at a much closer timeframe to become optimistic, been here too many times.  

It depends what gets you exited, for me I'd be happy with a few snowy streamers, but for others they will want blizzards and -15 cold pools.

[Cold Winter Night]

2 minutes ago, Ventnor Viking said:

I'm not being negative or rude to anyone, just being realistic. It "could" but hasn't and absolutely a frigid run hasn't shown yet so not worth talking about. I think it would be so much easier to discuss what's being presented. So many talk so positively and people get excited about maybes, I just cant. I need to see consistency at a much closer timeframe to become optimistic, been here too many times.  

You are right. The thing is though, it is exactly the lack of consistency that is strangely encouraging. Mild SW'lies always show up with great consistency, but look up the output now: They are nowhere to be seen, the Atlantic is dead, the spv too, opening an entire box full of "mights" and "coulds" that have been out of reach for many years.

[snowblizzard]

2 minutes ago, Battleground Snow said:

It depends what gets you exited, for me I'd be happy with a few snowy streamers, but for others they will want blizzards and -15 cold pools.

Yep, I'm definitely the latter! 

Dreams of January 1987 

Edited January 2, 2021 by snowblizzard

[Scott Ingham]

2 minutes ago, Allseasons-si said:

Whoah!!!,...dont say that in here lol you will get the place in uproar ha! ha!

you mean the ens are "flat lining" 

Hahahah lazy dislexic statement! 

Sorry peeps put the valium back in the cupboard hahaha

[Harsh Climate]

8 minutes ago, Ventnor Viking said:

I'm not being negative or rude to anyone, just being realistic. It "could" but hasn't and absolutely a frigid run hasn't shown yet so not worth talking about. I think it would be so much easier to discuss what's being presented. So many talk so positively and people get excited about maybes, I just cant. I need to see consistency at a much closer timeframe to become optimistic, been here too many times.  

Just goes to show you don't need a huge cold pool to the east or north east to get hammered before an upcoming cold spell.

Look at how mild russia and scandinavia was on the 19th nov 2010, then how cold it was just 27th november 2010, the SSW event in itself brought the cold air in, rather than it already been there to tap into.

Edited January 2, 2021 by Harsh Climate

[Allseasons-Si]

Just now, Scott Ingham said:

Hahahah lazy dislexic statement! 

Sorry peeps put the valium back in the cupboard hahaha

...And everyone's put the Prozak back,...FALSE ALARM!!!

[Mike Poole]

Just skim reading the posts, and the mood is optimistic.  I’ve not followed every run for a couple of days, simply because I know from experience that there is more noise than signal from the models in the direct run-up to a SSW!!  It isn’t that the models don’t model the strat, they do, but my issue is do they do it in sufficient resolution to be able to resolve an unusual phenomenon that takes place quickly, and which is quite rare?  

I’m moved by the argument for a QTR from this one, so far the journey has been much more similar to Mar 2018 run up.  Advantage is we’ve got a lot more of winter left.  

[TSNWK]

14 minutes ago, IDO said:

Looking at the gefs at d8 something is happening and if this is not a rogue suite then it is very interesting. The op seems tame compared to some of the members:

 

Steady on @IDO  as one of my go to posters for a dose of reality I’m very! interested if you’re interested shall we say

[Ventnor Viking]

1 minute ago, Battleground Snow said:

It depends what gets you exited, for me I'd be happy with a few snowy streamers, but for others they will want blizzards and -15 cold pools.

I agree. For me just seeing come consistency and talking about what's actually showing is a good place to start. If not you get pages of discussion of  what everyone wants to see and not what's being modelled, it must be confusing for the new members. 

[iapennell]

2 minutes ago, IDO said:

Yes, when the music stops we want to sit in the colder synoptic, so crucial that we keep the UK in the cold whilst in the early throws of the SSWE? Compare where the music may be stopping on the 06z to the 12z:

It maybe many days of potential -v- waiting for the SSW effects in a holding pattern?

 

Firstly, a Happy New Year to Netweather Forum members and those eagerly watching the charts hoping for a very cold and snowy synoptic set-up.

The weatheriscool website offers a forecast for mean winds to be up to 25 metres/ second (over 50mph) from the East along 60N by the 18th January, and given the tendency for Sudden Stratospheric Warmings over the Arctic (and the associated circulation) to work downwards into the troposphere over the following three weeks this does offer hope of a frigid easterly blast in early February. BUT...

1) The QBO in November (at the 30 mb level in the stratosphere high over the Equator) was on average over 11 metres/second (24 mph) from the West.

2) Most of the Equatorial waters are hotter than usual, even though there is an East/ Central Pacific La Niña (the worst possible place for Westerly AAM considerations as it strenthens the tropical easterlies to the west but any westerlies aloft wont touch the Peruvian Andes to be dissipated). A hotter-than-usual Equator overall means an active Intertropical Convergence Zone (ITCZ) and a healthy ITCZ means stronger north-easterly Trade Winds further north- busily pumping Westerly Atmospheric Angular Momentum (AAM) into the Northern Hemisphere general atmospheric circulation (thereby also increasing the sink for Westerly AAM elsewhere). 

3) The Norwegian Sea and Barents Sea remain free of ice and are warmer than usual- as is the North Atlantic, but Canada/ Greenland are already very cold. This not only fosters cyclonogenesis in the north-west Atlantic but warmer-than-usual waters further east and north wont discourage the depressions moving into those areas.

4) There have been Westerlies over the Tibetan Plateau- up to 20 mph in recent days. But this is not enough to negate the Westerly AAM- increasing effects of 20 mph (and above) North East and Easterly Trade Winds most places between 30N and the Equator (which you can see from "Windy" website).

Much Westerly AAM is being generated by North East Trade Winds, some of which will be offset by surface Westerlies over the Equatorial Indian Ocean. But most of the generated Westerly AAM will remain intact even after the sink effects of surface Westerlies over the Equatorial Indian Ocean and the limp Westerlies over Tibet are taken into consideration. The Westerly QBO over the Equator- feeding its influence down from the Stratosphere will add Westerly AAM to the tropospheric Northern Hemisphere circulation. This only leaves higher latitudes of the North Atlantic and North Pacific as sinks for this Westerly AAM- and (given the fundamentals of Canada-Greenland to North Atlantic baroclinicity and sea-surface warmth in the European Arctic) there is a strong likelihood that the UK and points west will be seeing those Westerlies. The Easterlies predicted for the Arctic Stratosphere can only make limited headway against these fundamentals.

So, on the basis of such meteorological fundamentals, there will not be a January 1987 or a February 1986 style Great Freeze in the UK in Winter 2020-2021. There will (probably) be this coming week and another week in early February with some very cold east winds, some sharp night frosts and snow-showers (as the predicted Sudden Stratospheric Warming feeds its influence downwards) but no month-long freeze with nights below -10C and deep snow across Britain.              

[Allseasons-Si]

Just for fun at that range but the gfs/p is going for another surge of height's into Greenland.

[saintkip]

3 minutes ago, iapennell said:

Firstly, a Happy New Year to Netweather Forum members and those eagerly watching the charts hoping for a very cold and snowy synoptic set-up.

The weatheriscool website offers a forecast for mean winds to be up to 25 metres/ second (over 50mph) from the East along 60N by the 18th January, and given the tendency for Sudden Stratospheric Warmings over the Arctic (and the associated circulation) to work downwards into the troposphere over the following three weeks this does offer hope of a frigid easterly blast in early February. BUT...

1) The QBO in November (at the 30 mb level in the stratosphere high over the Equator) was on average over 11 metres/second (24 mph) from the West.

2) Most of the Equatorial waters are hotter than usual, even though there is an East/ Central Pacific La Niña (the worst possible place for Westerly AAM considerations as it strenthens the tropical easterlies to the west but any westerlies aloft wont touch the Peruvian Andes to be dissipated). A hotter-than-usual Equator overall means an active Intertropical Convergence Zone (ITCZ) and a healthy ITCZ means stronger north-easterly Trade Winds further north- busily pumping Westerly Atmospheric Angular Momentum (AAM) into the Northern Hemisphere general atmospheric circulation (thereby also increasing the sink for Westerly AAM elsewhere). 

3) The Norwegian Sea and Barents Sea remain free of ice and are warmer than usual- as is the North Atlantic, but Canada/ Greenland are already very cold. This not only fosters cyclonogenesis in the north-west Atlantic but warmer-than-usual waters further east and north wont discourage the depressions moving into those areas.

4) There have been Westerlies over the Tibetan Plateau- up to 20 mph in recent days. But this is not enough to negate the Westerly AAM- increasing effects of 20 mph (and above) North East and Easterly Trade Winds most places between 30N and the Equator (which you can see from "Windy" website).

Much Westerly AAM is being generated by North East Trade Winds, some of which will be offset by surface Westerlies over the Equatorial Indian Ocean. But most of the generated Westerly AAM will remain intact even after the sink effects of surface Westerlies over the Equatorial Indian Ocean and the limp Westerlies over Tibet are taken into consideration. The Westerly QBO over the Equator- feeding its influence down from the Stratosphere will add Westerly AAM to the tropospheric Northern Hemisphere circulation. This only leaves higher latitudes of the North Atlantic and North Pacific as sinks for this Westerly AAM- and (given the fundamentals of Canada-Greenland to North Atlantic baroclinicity and sea-surface warmth in the European Arctic) there is a strong likelihood that the UK and points west will be seeing those Westerlies. The Easterlies predicted for the Arctic Stratosphere can only make limited headway against these fundamentals.

So, on the basis of such meteorological fundamentals, there will not be a January 1987 or a February 1986 style Great Freeze in the UK in Winter 2020-2021. There will (probably) be this coming week and another week in early February with some very cold east winds, some sharp night frosts and snow-showers (as the predicted Sudden Stratospheric Warming feeds its influence downwards) but no month-long freeze with nights below -10C and deep snow across Britain.              

Said with such certainty, it’s like the weather Is predictable 

[MJB]

2 minutes ago, iapennell said:

Firstly, a Happy New Year to Netweather Forum members and those eagerly watching the charts hoping for a very cold and snowy synoptic set-up.

The weatheriscool website offers a forecast for mean winds to be up to 25 metres/ second (over 50mph) from the East along 60N by the 18th January, and given the tendency for Sudden Stratospheric Warmings over the Arctic (and the associated circulation) to work downwards into the troposphere over the following three weeks this does offer hope of a frigid easterly blast in early February. BUT...

1) The QBO in November (at the 30 mb level in the stratosphere high over the Equator) was on average over 11 metres/second (24 mph) from the West.

2) Most of the Equatorial waters are hotter than usual, even though there is an East/ Central Pacific La Niña (the worst possible place for Westerly AAM considerations as it strenthens the tropical easterlies to the west but any westerlies aloft wont touch the Peruvian Andes to be dissipated). A hotter-than-usual Equator overall means an active Intertropical Convergence Zone (ITCZ) and a healthy ITCZ means stronger north-easterly Trade Winds further north- busily pumping Westerly Atmospheric Angular Momentum (AAM) into the Northern Hemisphere general atmospheric circulation (thereby also increasing the sink for Westerly AAM elsewhere). 

3) The Norwegian Sea and Barents Sea remain free of ice and are warmer than usual- as is the North Atlantic, but Canada/ Greenland are already very cold. This not only fosters cyclonogenesis in the north-west Atlantic but warmer-than-usual waters further east and north wont discourage the depressions moving into those areas.

4) There have been Westerlies over the Tibetan Plateau- up to 20 mph in recent days. But this is not enough to negate the Westerly AAM- increasing effects of 20 mph (and above) North East and Easterly Trade Winds most places between 30N and the Equator (which you can see from "Windy" website).

Much Westerly AAM is being generated by North East Trade Winds, some of which will be offset by surface Westerlies over the Equatorial Indian Ocean. But most of the generated Westerly AAM will remain intact even after the sink effects of surface Westerlies over the Equatorial Indian Ocean and the limp Westerlies over Tibet are taken into consideration. The Westerly QBO over the Equator- feeding its influence down from the Stratosphere will add Westerly AAM to the tropospheric Northern Hemisphere circulation. This only leaves higher latitudes of the North Atlantic and North Pacific as sinks for this Westerly AAM- and (given the fundamentals of Canada-Greenland to North Atlantic baroclinicity and sea-surface warmth in the European Arctic) there is a strong likelihood that the UK and points west will be seeing those Westerlies. The Easterlies predicted for the Arctic Stratosphere can only make limited headway against these fundamentals.

So, on the basis of such meteorological fundamentals, there will not be a January 1987 or a February 1986 style Great Freeze in the UK in Winter 2020-2021. There will (probably) be this coming week and another week in early February with some very cold east winds, some sharp night frosts and snow-showers (as the predicted Sudden Stratospheric Warming feeds its influence downwards) but no month-long freeze with nights below -10C and deep snow across Britain.              

I don't quite get your last paragraph ? You say there will be some very cold winds and some sharp night frosts , but no nights of -10c ?? we have been very very close to -10c in this spell , so are you saying we will have a repeat of what we are seeing with regards cold?

[Ventnor Viking]

6 minutes ago, Cold Winter Night said:

You are right. The thing is though, it is exactly the lack of consistency that is strangely encouraging. Mild SW'lies always show up with great consistency, but look up the output now: They are nowhere to be seen, the Atlantic is dead, the spv too, opening an entire box full of "mights" and "coulds" that have been out of reach for many years.

Again I agree, speculation from nothing can spiral and confuse people, especially new comers. The Atlantic is dead and so is the SPV but nothing is being modelled to suggest anything other than bulk standard cold. Id love to sit here like so many and say the colds happening etc! But if you questioned me on that I couldn't back it up with clear evidence or strong reliability. My comments on what is actually being shown has been contested more than speculation posts and that is my point....its very odd.