Model output discussion - 5th December 2016 - Into Winter we go

[NorthernRab]

9 minutes ago, Steve Murr said:

Nothing of interest in the 12s

both the UKMO & GFS Awful...

Day 12- worse than 2015

Worse synoptically and in terms of weather conditions from a "coldie" perspective? Or worse in terms of verification / likelihood that it will actually happen? 

 

Almost definitely the latter. 

[Cheshire Freeze]

Just now, Mucka said:

I think there is probably some confusion between exactly what time period people are talking about - especially re FI.

It would be very difficult to get the charts we want medium term from here not impossible but highly unlikely.

Day 8 to 12 or so we can expect positive height anomalies around UK/NW Europe.

The Christmas period is up for grabs though as far as I can tell even if high pressure favoured mid lat around our location.

I'm definitely not seeing the atlantic Trough sceuro high as nailed on there even allowing for west/east variation and degrees of angular shift within the jetstream.

Christmas-New Year week ; )

[karlos1983]

5 minutes ago, Bullseye said:

Confused by the posts in past 30 mins. We have went from UKMO looking good/interesting post 144hr to next post saying no blocking possible in next 16 days to good cold pool of -4 around east England then to round it off next post saying "awful charts, worse than 2015". Onto ECM it is... which won't be much help I would imagine.

Bottom line is that whilst we've got signs of heights to our NE (which we do) then we have a good chance. To me eyes, it looks like the low that approaches the uk around 144 has definitely slowed and trended south. So at those timescales we have an opportunity for further corrections. I find it odd how usually this would be getting more interest. Perhaps I'm missing something.

Then the models start to hint again at heights rising to the East /  NE, so it's going to be interesting to see if that continues to be modelled 

Edited December 10, 2016 by karlos1983

[Mucka]

1 minute ago, CreweCold said:

Christmas-New Year week ; )

Pretty much anywhere 22nd onward could have HLB or shift ridging from East focussed to West based IMO and I'm not ruling out the sceuro high or evn zonal!

I know. informative right? 

[Summer Sun]

At least this would offer the prospect of some frost and fog

[Cheshire Freeze]

2 minutes ago, IDO said:

That is one frame (and not helpful) showing weak heights and is a moving feast. Better to show the previous frames so we can in fact see that it is not a block, just a pocket of weak heights moving in the flow with nominal WAA to pump it up:

D14D16 

A few frames later it will be in Russia/Siberia, and the UK swamped by lower pressure. Though D16 so usual caveats...

OK- so that isn't a particularly impressive block but I ask you...was the Jan 2013 block impressive in terms of absolutes? No.

Also I'm highlighting it because such a scenario (with much more impressive MSLP numbers) has been floating around the GEFS for a couple of days. 

I genuinely do not know whether your aim on this forum is to act as forum WUM but you do sometimes convey a strong sense of wanting to be so.

[knocker]

7 minutes ago, Bullseye said:

Confused by the posts in past 30 mins. We have went from UKMO looking good/interesting post 144hr to next post saying no blocking possible in next 16 days to good cold pool of -4 around east England then to round it off next post saying "awful charts, worse than 2015". Onto ECM it is... which won't be much help I would imagine.

Don't worry too much about the cold pool as it's a shallow transient feature that emanated from the trough to the SE. On this chart just a little later you can see the next one on it's way along the southern flank of the HP but this time it will be further east as the HP has moved east. I hope that clarifies that a little

 

Edited December 10, 2016 by knocker

[Mucka]

Easterly T96!

[carinthian]

27 minutes ago, chris55 said:

UKMO 144 a good chart again today, even though the initial trough makes it through to our north, whats following behind is interesting. A ridge building ahead of the second Low and that little shortwave heading south east. The initial trough should fill in situ allowing a second attempt behind.

 

Interest here from UKMO and GFS ,both looking for a change at 144t. Not impossible to get a Scandinavia High in position from this range. The key features required are for much lower heights to take place over Southern Europe in the period 144-240t period. This can be achieved with trough distruption combined with a NW jet sending energy into Europe and lowering heights there and maintaining high pressure to the NE to stop sinking. Both these charts below could prelude to this development , even though the UKMO latest is a bit flatter of the two at the moment.

C

Edited December 10, 2016 by carinthian

[doghouse]

12 minutes ago, Jeremy Shockey said:

i thought that both the GFS and UKMO were actually quite promising up to 192 ( which is all i care about at the moment ) . Hope you cheer up soon Steve . Sliders possible ?

Yeh, Steve snap out of it man. Why not join with GP and find a route to cold instead of sounding like IDO. Come on, ye know ye want to

[Singularity]

Odd how UKMO diverges so strongly with the shortwave at just +72 hours, with pretty extreme knock-on effects.

ARPEGE votes GFS (albeit with the trough not making quite so much inroads) but what will ECM weigh in with later?

Despite ramming that disrupting low in quite a bit further than the 00z (just typical after I was thinking to myself 'don't these often make less inroads than initially predicted?'), GFS is maintaining a 'taste of continental chill' theme for next weekend, which coupled with a lot of dry weather will seem a safe bet unless ECM goes off on some other route this evening. I wonder how much the GLAAM bias is impacting the N. Atlantic jet in terms of opportunities for breaks to develop and facilitate trough disruption.

There's actually a consistent long-term signal to be found with the past 4 or 5 GFS runs; as the Pacific MJO activity comes into effect, a trough digs down in the N. Atlantic. Trouble is, it's tended to blow up into too large a feature for us to see interesting results via Scandi height rises... but the 12z finally gets close enough to illustrate the potential there. Yes, I know - that word's gaining taboo status on this forum these days 

 

[Jason M]

As things stand right now its basically a Bartlett set up with a persistent band of high pressure to our SE (IMO of course) . If you were able to run forward from the end of the GFS FI the second attempt would almost certainly fail for exactly the same reasons. Whilst pressure remains high to our south there is literally no chance of anything interesting.

Given the state of the background signals to date i'm surprised we have arrived at this point, but nonetheless we are where we are .

All we can do is hope for a change tbh.

 

[IDO]

4 minutes ago, CreweCold said:

OK- so that isn't a particularly impressive block but I ask you...was the Jan 2013 block impressive in terms of absolutes? No.

Also I'm highlighting it because such a scenario (with much more impressive MSLP numbers) has been floating around the GEFS for a couple of days. 

I genuinely do not know whether your aim on this forum is to act as forum WUM but you do sometimes convey a strong sense of wanting to be so.

But that was the exception that proved the rule, getting the perfect scenario like Jan 13 may never happen again in our life times, so we do need something more than what was showing, though the fact we are arguing over D16 charts sums it up really! 

GEM is flat as well: 

[Cheshire Freeze]

1 minute ago, IDO said:

But that was the exception that proved the rule, getting the perfect scenario like Jan 13 may never happen again in our life times, so we do need something more than what was showing, though the fact we are arguing over D16 charts sums it up really! 

GEM is flat as well: 

Meanwhile GFS control gives it a jolly good go..at just 120 hrs

And, I think me and you both know that GEM would be far from flat 48 hrs on from that chart!

Edited December 10, 2016 by CreweCold

[karlos1983]

Yup and the mean has a more negatively tilted low than the 06z. 

 

Edited December 10, 2016 by karlos1983

[tight isobar]

For signs of 'possible' eventual  evolutions thus far (excluding ecm)..soon to trickle out' sign for me via 12z are very encouraging. 

With placement of high wedged a little further north/morth east' the game on scenario would be well underway...

Lets have a look at 12z ecm for compare and evolution. 

Edited December 10, 2016 by tight isobar

[Cheshire Freeze]

2 minutes ago, karlos1983 said:

Yup and the mean has a more negatively tilted low than the 06z. 

 

Yes, this!

Look at the angle of advection on the western side of the block...

May not impact us this time round but it will have consequences going forward...as I keep saying.

Edited December 10, 2016 by CreweCold

[Mucka]

Can't help feeling there is misplaced shortterm optimism and long range pessimism - I've been guilty of both before now but never at the same time

Edited December 10, 2016 by Mucka

[karlos1983]

1 minute ago, CreweCold said:

Yes, this!

Look at the angle of advection on the western side of the block...

May not impact us this time round but it will have consequences going forward...as I keep saying.

It flattens out pretty quickly after that, but I expected that. 

[Singularity]

3 minutes ago, Mucka said:

Can't help feeling there is misplaced shortterm optimism and long range pessimism - I've been guilty of both before now but never at the same time

I know what you mean - I believe that hoping for much more than a bit of seasonal frost and/or fog by next weekend is setting the bar too high, while looking at longer-term GFS with its flat bias (due to low AAM bias) and assuming that the Atlantic troughs won't amplify enough is indeed pessimistic.

This forum would be more entertaining if any chart beyond a week's range was considered a 'suggestion' rather than 'what will likely happen'. We're strongly encouraged to do that with cold charts, so why not mild ones as well?

Edited December 10, 2016 by Singularity

[Mucka]

A Christmas miracle?

Ensembles definitely show a little interest but I'm not buying. (Wouldn't want to jinx it anyway)

Edited December 10, 2016 by Mucka

[Cheshire Freeze]

5 minutes ago, Mucka said:

Can't help feeling there is misplaced shortterm optimism and long range pessimism - I've been guilty of both before now but never at the same time

At 384 hrs in last night's 18z GEFS there was a cluster of approx 50% that had significant N blocking or imminent potential. Can this suite get close?

[chris55]

28 minutes ago, Chris.R said:

 I'm getting mixed messages here again! 

Anything in the forecast models beyond the more reliable 96/120 timeframe will always be open to interpretation, and that is the very nature of forecasting. We cant simply take anything at face value beyond these time-frames and thus we will end up with different people interpreting the data in different ways. And there certainly is a plethora of data to interpret!!    

[bybo1999]

2 minutes ago, Snowmut said:

WUM?

Wind Up Merchant

[Summer Sun]

The high is a bit further north on this ens run compared to the 06z

850's a bit lower for eastern Europe too

Edited December 10, 2016 by Summer Sun