Model Output Discussion 18th Nov.2013-12z onwards.

[SMU]

Morning All -

 

 nothings changed to much overnight- still a bit of a stalemate- however we have lost the stella charts- the middle ground being the preferred option-

 

ECM moving to the original UKMO from a few days ago -- which yes includes a move to the overrunning GFS pattern, however the GFS was way to flat, with the ECM to amplified.

 

Middle ground the form horse still with no sign of mild.

S

[Frosty.]

Morning All -

 

 nothings changed to much overnight- still a bit of a stalemate- however we have lost the stella charts- the middle ground being the preferred option-

 

ECM moving to the original UKMO from a few days ago -- which yes includes a move to the overrunning GFS pattern, however the GFS was way to flat, with the ECM to amplified.

 

Middle ground the form horse still with no sign of mild.

S

The latest Ecm / Gefs 00z mean gradually shunts the cold block further east with the atlantic knocking on the door not far beyond T+240 hours, but with cold zonality rather than mild air from the azores, I would say things have changed quite a bit between 12z last night and 00z today, not really a middle ground as far as I can see, more of an eventual collapse and start fresh with cold zonal weather during early / mid dec but you are the expert steve..this is just my opinion based on the charts i've posted this morning.

Edited November 19, 2013 by Frosty.

[fergieweather]

[quote name="Steve Murr" post="2839787"

Middle ground the form horse still with no sign of mild.

S

[EML Network]

Hi Steve, actually the latest DECIDER products do continue hinting at milder unbiased SW flow into early December for at least western UK. A minority of EPS postage stamps retain the anticyclonic pattern throughout, but for now UKMO lean towards the stronger DECIDER signal & an eventual return to westerly mobility in one shape or another. Strong signal for below average temps starts to wane into 10-15d period (some members having full-on mobility across NW parts even by day 9).Cheers, Ian

 

Well there you have it, the first nail in the coffin.To be fair the GFS has pushed the blocking High further and further South on each run, it was only a matter of time before it sank completely.

 

the writing has been on the wall for a few days now and I think a lot of seasoned model watchers never really brought into the concept of a cold spell coming anyway..I know I didn't.

 

High pressure rules the roost and the Atlantic is always going to try and make in roads, being the predominant weather type in the UK, stale mate for the time being and it's open to debate thereafter.

 

There's still opportunities ahead for a plunge of cold from the North, but there's a distinct lack of cold in the East and until the cold sets up shop there, I'm not going to get excited about anything I see.

[Frosty.]

The GEM 00z also shows the atlantic gearing up to spill in with unsettled weather already into the northwest of the uk, so it's not looking like the anticyclonic spell will hang around for too long before the weather becomes more zonal but more emphasis on cool / cold zonality rather than mild.

[Tamara]

I think the anticyclonic spell will be welcomed by many for however long it lasts after incessant autumn rain . This has always been about degress of amplification of the pattern for an atlantic ridge and not any definitive high latitude block, so in that sense although there was a hope that a greater degree of amplification aka ECM might occur, nothing untoward has happened that should result in too much disappointment imo. 

 

From what I can glean from the NAEFS anomalies for the extended period, the jet stream wants to retain something of a willingness to disrupt low pressure on a WNW tilt, and so, whilst a long way off, another atlantic amplification scenario could well follow any return to a milder westerly pattern once the High loses its influence

Edited November 19, 2013 by Tamara תָּמָר

[draztik]

Looking at the 10-15 day outlook from the ensembles shows some divergence, with GEM trending towards above average for Ireland and average for most of the UK. GEFS shows much of the UK still below average at this timeframe.

[Mucka]

From a purely neutral point of view I think the GFS has been closest predicting the mid term, both with our initial pattern and the up stream developments.

 

But there may be a twist in the tale. If GFS has been leading the way (I know it's debatable and some will argue otherwise and that's fine) then ECM is probably playing catch up at the moment which makes the current GFS developments quite interesting - more so than would be normally the case without cross model support.

Both the 00z and 06z want to split the jet at the mid range (around 144) and send an area of low pressure south (more a shortwave) to the West of the UK which could give us a second bite of the cherry as it could force heights NE into Greenland behind it as the next low comes in (think of the high getting squeezed between the two areas of low pressure like a tube of toothpaste)

 

 

 

Now at the moment there is not enough energy being modelled into the Southern arm of the split to make the difference while behind the jet rages over the top so the pattern gets flattened out again thus the potential will go unnoticed with just a cursory glance at the charts.

Admittedly this is still a bit lot of a long shot and we need the GFS to stick with sending energy South and the Euros to come on board before really getting interested but there is a small possibility of rapid developments to our NW between 144h and 192h.

 

It is a bit of a straw at the moment admittedly,especially given all the longer range trends for the opposite to occur (a flattening pattern rather than a reamplified one as Fergie has stated and this signal is said to be strong) so don't expect a miracle. I just thought it worth mentioning for those who enjoy model watching. This post may be obsolete after this evenings output even.

Edited November 19, 2013 by Mucka

[Tamara]

I'm not sure with all that continues to go on over the pacific side of the NH and the Canadian arctic that the pattern will necessarily be a flat one when the westerlies return

 

 

 

Edited November 19, 2013 by Tamara תָּמָר

[Frosty.]

The GEFS 06z mean shows high pressure slap bang on top of the uk @ T+168 hours with slight frosts and fog which would be slow to clear, some areas would remain cold and foggy all day in such a set up. Towards T+240 the anticyclone is already slowly drifting away southeastwards with the atlantic weather already into the northwest corner of the uk, gradually the fine spell is eroded and the weather turns unsettled and windier with a broadly westerly upper flow..no middle ground here, every model I have looked at shows an eventual breakdown from the west through early december.

Edited November 19, 2013 by Frosty.

[Mucka]

Just a quick follow up to my previous straw clutcher.

I had quick look through GFS 06z ensembles to see if I could find any charts that illustrate what I was saying and I found just two and both of these still have the jet roaring over the top thereafter. Still, they do illustrate what I was talking about quite well even if the potential is not realised.

 

[shedhead]

Well there you have it, the first nail in the coffin.

To be fair the GFS has pushed the blocking High further and further South on each run, it was only a matter of time before it sank completely.

 

the writing has been on the wall for a few days now and I think a lot of seasoned model watchers never really brought into the concept of a cold spell coming anyway..I know I didn't.

 

High pressure rules the roost and the Atlantic is always going to try and make in roads, being the predominant weather type in the UK, stale mate for the time being and it's open to debate thereafter.

 

There's still opportunities ahead for a plunge of cold from the North, but there's a distinct lack of cold in the East and until the cold sets up shop there, I'm not going to get excited about anything I see.

Indeed, GFS has handled the siuation very well so far, so whilst things still have to happen the fact it's dragged ECM screaming and kicking back into line pretty much say it all.... and not for the first time I might add.  As Ian F has intimated the longer term trend is towards a milder, flatter pattern as we go into Winter proper, so perhaps best to enjoy the current cold spell and hopefully the upcoming frosty conditions- well until the next plunge shows up at T+384hrs of course....

[Frosty.]

I don't think it will be a mild flow, at worst it will alternate between tropical maritime and polar, and in a fast moving zonal pattern, increased amplification can occur so it's not bad actually, FI looks like slowly becoming more lively again with some interest, I don't think we would see a sw / ne aligned jet with mild mush for weeks and weeks.

[shedhead]

I don't think it will be a mild flow, at worst it will alternate between tropical maritime and polar, and in a fast moving zonal pattern, increased amplification can occur so it's not bad actually, FI looks like slowly becoming more lively again with some interest, I don't think we would see a sw / ne aligned jet with mild mush for weeks and weeks.

I'm not sure anyone has said we will see a mild flow Frosty.  Ian F has suggested a 'milder' flow, but that's about it for now, so perhaps the 'M' word that gets so many people ticking needs to be used in the right context....at least for now.

Edited November 19, 2013 by shedhead

[Yarmy]

Since we are all a little bit in the hunt for straws, it's worth noting that recent runs bring cold flooding into Eastern Europe:

 

 

It's still November and somewhere down the line the short term loss could be longer term gains.

[Purga]

06z dreadful in FI with purples over Greenland and a Bartlett / Euro high in full glory

 

Other to that, a fairly benign dry cool spell coming up but nothing severe by any stretch of the imagination even with ECM

 

 

Sleepsville ...

[SnowObsessor90]

The fact that the models now show anticylconic with a transition back to a more westerley based pattern being more likeley doesn't surprise at all, called it days back when Models were still fairly early into their "transition phase", really the farce of last December should already have served as enough of an eye opener for users on this site.

[Barry12]

06z dreadful in FI with purples over Greenland and a Bartlett / Euro high in full glory

Other to that, a fairly benign dry cool spell coming up but nothing severe by any stretch of the imagination even with ECM

Sleepsville ...

Good job it's in FI and very unlikely to verify

[Snowyowl9]

Long way off but chilly continental easterly/SE flow possible.

http://www.wetterzentrale.de/pics/Rtavn1627.png

http://www.wetterzentrale.de/pics/Rtavn16217.png

[Frosty.]

The fact that the models now show anticylconic with a transition back to a more westerley based pattern being more likeley doesn't surprise at all, called it days back when Models were still fairly early into their "transition phase", really the farce of last December should already have served as enough of an eye opener for users on this site.

I was really hoping for a nov / dec 2010 type spell but realise that's gone up in smoke now, what i'm hoping for now is cold zonality to take over during december with a higher risk of significantly colder incursions as the jet digs further south, having said that, i'm looking forward to the frosty anticyclonic spell later this week, it should last around 7 days the further southeast one happens to be, turning more unsettled towards the northwest of the BI during the second half of next week.

[The PIT]

Classic case of people allowing themselves too be hoodwinked by deep FI charts egged on in some cases by more experienced posters. The comments against John Holmes when he politely warned people not to get carried away seem a bit foolish now.

Even the next run could show the beast from the east  or the Indian summer from Madrid. Just down get carried away with it until it gets down to around t120.

Anyway it still going too on the cold side for a while yet so enjoy and chill out.

Edited November 19, 2013 by The PIT

[Summer Sun]

Some increasing signs now of a rather dry spell developing from mid next week

 

[andymusic]

Joe's take on euro snowfall - the next 7 - 8 days

 

should COOL things down a bit

Edited November 19, 2013 by andymusic

[terrier]

I was really hoping for a nov / dec 2010 type spell but realise that's gone up in smoke now, what i'm hoping for now is cold zonality to take over during december with a higher risk of significantly colder incursions as the jet digs further south, having said that, i'm looking forward to the frosty anticyclonic spell later this week, it should last around 7 days the further southeast one happens to be, turning more unsettled towards the northwest of the BI during the second half of next week.

Dont think they was ever any signs of a nov/dec freeze up frosty. But at least what we have now is better than nothing. Certainly better than the mild mush we had in the 90s and hopefully jan might bring better news. Because by what i can understand from ian f is that december might be a long month for us coldies. Lets hope jan and feb delvier the goods.

[stewfox]

Deleted

 

 

Edited November 19, 2013 by stewfox