Model Output Discussion 01/09/17

[Cheshire Freeze]

3 minutes ago, blizzard81 said:

Dartboard low in the Atlantic last few frames of the ecm doesn't look too pretty with regards to long term cold for our shores. If this comes off then we can only hope it is forced south-eastwards under pressure from the Arctic high. That would open the floodgates to proper cold. 

It's not bad at all hemispherically but for the UK it's trash...as ever. Over the past few years whenever the AO has gone negative we've found ourselves in the path of the WAA so that other areas of the hemisphere get the cold.

[nick sussex]

Both the GFS and ECM develop some interesting NH patterns in their later outputs. Neither though show a straightforward route to much colder conditions.

The former looks in danger of developing a west based negative NAO although it just about manages to clear low pressure sufficiently east but this is well into the very unreliable part of its run.

The ECM continues with its morning trend but blows up the low to the west, before this it develops a quite common cold precursor, high pressure getting sucked north ahead of digging Atlantic energy.

The reason we don't get a more interesting T240hrs chart is the lack of amplitude of that upstream low so the energy piles over the top, more amplification upstream would help suck high pressure further north which then would force some energy to disrupt se from that low. Of course at this range we're likely to see a lot more changes moving forward.

Earlier theres a colder weekend coming up with a brief colder nw flow, positively the ECM starts weakening the PV chunk to the north at T168hrs and it looks weaker than earlier runs.

The ECM is a case of promising you a high quality dinner and delivering you egg and chips so certainly room for it given the interesting NH pattern to deliver something better tomorrow.

 

 

 

[blizzard81]

5 minutes ago, CreweCold said:

It's not bad at all hemispherically but for the UK it's trash...as ever. Over the past few years whenever the AO has gone negative we've found ourselves in the path of the WAA so that other areas of the hemisphere get the cold.

Indeed. Oh well, at least the north east US didn't end up with the  winter goodies on this run. 

[blizzard81]

6 minutes ago, nick sussex said:

Both the GFS and ECM develop some interesting NH patterns in their later outputs. Neither though show a straightforward route to much colder conditions.

The former looks in danger of developing a west based negative NAO although it just about manages to clear low pressure sufficiently east but this is well into the very unreliable part of its run.

The ECM continues with its morning trend but blows up the low to the west, before this it develops a quite common cold precursor, high pressure getting sucked north ahead of digging Atlantic energy.

The reason we don't get a more interesting T240hrs chart is the lack of amplitude of that upstream low so the energy piles over the top, more amplification upstream would help suck high pressure further north which then would force some energy to disrupt se from that low. Of course at this range we're likely to see a lot more changes moving forward.

Earlier theres a colder weekend coming up with a brief colder nw flow, positively the ECM starts weakening the PV chunk to the north at T168hrs and it looks weaker than earlier runs.

The ECM is a case of promising you a high quality dinner and delivering you egg and chips so certainly room for it given the interesting NH pattern to deliver something better tomorrow.

 

 

 

We have had a few chances over the last few years of such a scanario but all have failed miserably. Either the Arctic high doesn't play ball or as you say the Atlantic scuppers it all. Jan 1947 is a perfect example of when it actually all comes together without any hiccups. 

[comet]

Wave 2 geopotential height rises in FI now showing on gfs instant weather maps. Got to be one of the longest sausage shaped vortices at t300 70mb before heading towards a split at end of run at 50,70 and 30mb.

Now that has got my attention.

[knocker]

The ecm 850mb temp and contour. I suspect the EPS will continue to indicate the retrogressing of the Canadian vortex and the pattern change in the 8-13 period

[cheshire snow]

@nick sussex

Great to see you back for another Season,your Quotes at the end of your posts always

Make me Chuckle,Hopefully be a good one,no doubt your scoring system will come into

Play at some stage.

C.S. 

[Man With Beard]

Tonight's ECM D10 is actually very close where the main ensemble clusters were this morning. They led quickly to a UK low and decent heights around Greenland/Iceland.

[chionomaniac]

11 minutes ago, CreweCold said:

It's not bad at all hemispherically but for the UK it's trash...as ever. Over the past few years whenever the AO has gone negative we've found ourselves in the path of the WAA so that other areas of the hemisphere get the cold.

Dartboard low from the ECM is totally unattached to the fragmented vortex here. A good pattern hemispherically as you say and that is certainly not a trash chart (longer term) for the UK in my eyes. Not that it won't be completely different at T+240 on the next run though.....

(Note the developing trough to the SW of the dartboard and the southerly displaced jet) I would much rather see this than a compact vortex

[nick sussex]

1 minute ago, blizzard81 said:

We have had a few chances over the last few years of such a scanario but all have failed miserably. Either the Arctic high doesn't play ball or as you say the Atlantic scuppers it all. Jan 1947 is a perfect example of when it actually all comes together without any hiccups.

The real problem as has been the case for many recent winters is the lack of amplitude upstream when you need it. The situation at 192 and 216 hrs is primed to see high pressure sucked north to then meet up with developing heights near Svalbard, instead the Atlantic low gets fed some energy from the departing Greenland low heights blows up into the bowling ball low to then run over the top and likely trap the UK on the warmer side of the jet.

That could still change though given the timeframes, the overall pattern shows promise but as we've seen from recent winters promise has rarely delivered much. It's early in the season though so plenty of time to see some changes.

 

[Cheshire Freeze]

2 minutes ago, chionomaniac said:

Dartboard low from the ECM is totally unattached to the fragmented vortex here. A good pattern hemispherically as you say and that is certainly not a trash chart (longer term) for the UK in my eyes. Not that it won't be completely different at T+240 on the next run though.....

(Note the developing trough to the SW of the dartboard and the southerly displaced jet) I would much rather see this than a compact vortex

Perhaps I'm just being impatient 

It is a good chart from a NH perspective but we all know that these 'fly in the ointments' can come thick and fast for the UK until the overall background picture is no longer conducive to tapping any cold! Then we all sit here long faced, scratching our heads and picking the bones of what went wrong. 9 times out of 10 this is simply how it works for the UK unfortunately.

Edited November 7, 2017 by CreweCold

[LRD]

35 minutes ago, CreweCold said:

It's not bad at all hemispherically but for the UK it's trash...as ever. Over the past few years whenever the AO has gone negative we've found ourselves in the path of the WAA so that other areas of the hemisphere get the cold.

From the ECM 240 chart...

http://www.wetterzentrale.de/de/topkarten.php?map=1&model=ecm&var=1&run=12&time=240&lid=OP&h=0&mv=0&tr=24#mapref

I can see pressure rising over Greenland, the dartboard low joining forces with that southerly tracking low to then head into Iberia and Italy and placing the UK on the cold, northern side of that low. I don't know but did something similar happen in Dec 1981? It will change of course but I reckon that's what would happen

 

Edited November 7, 2017 by LRD

[Cheshire Freeze]

4 minutes ago, LRD said:

From the ECM 240 chart...

http://www.wetterzentrale.de/de/topkarten.php?map=1&model=ecm&var=1&run=12&time=240&lid=OP&h=0&mv=0&tr=24#mapref

I can see pressure rising over Greenland, the dartboard low phasing with that southerly tracking low to then head into Iberia and Italy and placing the UK on the cold, northern side of that low. I don't know but did something similar happen in Dec 1981? It will change of course but I reckon that's what would happen

 

It doesn't look like the logical progression to me...but what do I know.

The jet will follow the path of least resistance, which means that heading into Europe is out of the equation as there is a displaced 1025 mb wedge of heights there!

Best case scenario from that chart is WAA gets far enough N around the UK to allow HP to replace that Scandi troughing. From there we, in theory, could see HP stretched from Scandi to Greenland with the jet being deflected underneath. It's a complicated route for all that to fall into place without other spoilers popping up though! 

[Daniel*]

Good news for common folks! 

 

[LRD]

4 minutes ago, CreweCold said:

It doesn't look like the logical progression to me...but what do I know.

The jet will follow the path of least resistance, which means that heading into Europe is out of the equation as there is a displaced 1025 mb wedge of heights there!

Best case scenario from that chart is WAA gets far enough N around the UK to allow HP to replace that Scandi troughing. From there we, in theory, could see HP stretched from Scandi to Greenland with the jet being deflected underneath. It's a complicated route for all that to fall into place without other spoilers popping up though! 

The Euro heights in that chart look relatively weak to me

Edited November 7, 2017 by LRD

[nick sussex]

21 minutes ago, cheshire snow said:

@nick sussex

Great to see you back for another Season,your Quotes at the end of your posts always

Make me Chuckle,Hopefully be a good one,no doubt your scoring system will come into

Play at some stage.

C.S. 

Thanks that’s nice of you.  You can normally correlate my quotes with how irritated I am with the outputs! 

You’ll know things are bad if I start using my film analogies! 

Just for you the ECM scores a 7/10 for artistic impression but only a 4/10 for technical merit ! Unfortunately it fell on two triple salkos  and the triple axel! 

[Cheshire Freeze]

5 minutes ago, LRD said:

The Euro heights in that chart look relatively weak to me

Remember, we were undone by continental heights last winter. Never underestimate them...the issue is the modelling often does (or has at least seemed to in recent years). I can't get the EC output out of my head from last winter where it constantly progged Euro heights falling...wrongly!

[feb1991blizzard]

8 minutes ago, CreweCold said:

It doesn't look like the logical progression to me...but what do I know.

The jet will follow the path of least resistance, which means that heading into Europe is out of the equation as there is a displaced 1025 mb wedge of heights there!

Best case scenario from that chart is WAA gets far enough N around the UK to allow HP to replace that Scandi troughing. From there we, in theory, could see HP stretched from Scandi to Greenland with the jet being deflected underneath. It's a complicated route for all that to fall into place without other spoilers popping up though! 

Yes and as per my last post, even with no shortwave spoiler and the perfect synoptics, you still might struggle to get the -8c isotherm anywhere near the UK as its early - I just cant see this one happening I'm afraid and then you've wasted a good chance and we need to take early chances because if that PV gets its act together in Mid December, your really staring down the barrel at another wasted year again.

[-uksnow-]

For what its worth, UKMO D7 back the ECM with a more amplified US pattern than the GFS - would expect the GFS to find this solution over the next few runs.

[LRD]

1 minute ago, CreweCold said:

Remember, we were undone by continental heights last winter. Never underestimate them...the issue is the modelling often does (or has at least seemed to in recent years). I can't get the EC output out of my head from last winter where it constantly progged Euro heights falling...wrongly!

To be fair, continental heights scupper most winters! Thing is I don't remember too much in the way of Greenland highs being modelled last winter. You can see in that chart that something serious is brewing in that region. But I s'pose we're talking about a scenario that will have disappeared in 12 hours anyway!

[Cheshire Freeze]

6 minutes ago, feb1991blizzard said:

Yes and as per my last post, even with no shortwave spoiler and the perfect synoptics, you still might struggle to get the -8c isotherm anywhere near the UK as its early - I just cant see this one happening I'm afraid and then you've wasted a good chance and we need to take early chances because if that PV gets its act together in Mid December, your really staring down the barrel at another wasted year again.

If we fail to see anything of interest strat wise then it's really only a matter of when and not if the increased zonal winds make their way down to affect the trop. Like last year, this could be a critical period for our winter hopes. If we get it right then we could be looking at an OK winter. If not, I suspect those horrid CFS and GLOSEA winter anomaly charts may not be far off the mark.

I knew as soon as that progged spell mid-late November last year failed that it was curtains going forward and I said as much at the time. 

Edited November 7, 2017 by CreweCold

[LRD]

The trends are there for polar heights in all models and the professionals are becoming more confident of cold weather towards the end of November as per the last 3 or 4 met office updates

Edited November 7, 2017 by LRD

[ANYWEATHER]

Hello Folks... I cant understand how some people write off cold weather even before we start Winter,  Tonight will be the fourth frost we have had , how does that compare with the last couple of years The model output is packed with frequent bouts of cold weather, in the next week , I think the saying is enjoy the present weather and not what might or not in the days ahead...! Anyway, both ecm and gfs show a split vortex , in the days ahead , the devil will be in the detail...c,mon Folks its only early November....

[Cheshire Freeze]

5 minutes ago, LRD said:

The trends are there for polar heights in all models and the professionals are becoming more confident of cold weather towards the end of November as per the last 3 or 4 met office updates

Again, it means little.

The BBC/Metoffice were fully confident of colder weather with snow for early December last year. They were saying this mid November. There was a screenshot on here for the look ahead summary on their extended forecast but it seems to have been taken down from the thread....

Edit found it..

Edited November 7, 2017 by CreweCold

[Snowman.]

1 minute ago, CreweCold said:

Again, it means little.

The BBC/Metoffice were fully confident of colder weather with snow for early December last year. They were saying this mid November. There was a screenshot on here for the look ahead summary on their extended forecast but it seems to have been taken down from the thread....

Edit found it..

I can't quite see the problem. They made a forecast one that was well rounded and had the highest PROBABILITY, it was wrong but that's why it's a forecast. We don't have crystal balls and magic rituals to predict the weather accurately all we have is computer models which solve large equations to predict the weather.

They among with many made a forecast that didn't come to fruition. Which is why it's a forecast not a statement.