Model Output Discussion 1200 hrs 15/11/14

[Captain Shortwave]

Probably our stopping point tonight regarding confidence. It does look likely that we will see a cold front push south east on Saturday to leave brighter and cooler conditions behind. We should see a couple of fine days with overnight frosts before this low approaches from the west.

But with relation to the Azores high, there is an area north of this which we will need to watch. We should see heights develop from the plume of warm air stretching up the GIN corridor. How the Atlantic low reacts to this will determine where we head next. At the moment the pattern goes too far east and it turns unsettled for the UK. Will it happen in reality though.

[Polar Maritime]

ECMWF also showing the Low dropping S/E over the UK from the N/W.

 

[swfc]

Anyones thought on the ecm at 240hrs??Im probably wrong but is it not a zonal chart with the pv gaining strength?

[nick sussex]

The best analogy that can be used to describe the current output is England trying to do a penalty shoot out at the World Cup, just one miss after another!

 

A serious of opportunities where one slips on wet grass, the other blazes over the bar and the other hits the post!

 

The catalogue of misses one can correlate with the output, the shortwave that hangs around for too long, the ECM now has a less developed low over the USA and not enough interaction with the PV chunk etc etc.

 

The last vestige of hope is something alluded to by CS, which I will call the GOH Gap of Hope!

 

 

Either something develops here to add some forcing on the trough or its a one way ticket to mild especially as the more favourable upstream pattern shown by the ECM 00hrs hit the buffers.

 

The ECM is fast becoming the GFS which I used to deride frequently and is fast becoming King only upto T144hrs but a complete chump after that point.

 

So my fellow coldies its either the GOH or I fear my helpline will need a big influx of new telephone operatives!

Edited November 18, 2014 by nick sussex

[IDO]

ECM at D10: 

 

Up till then pretty much in line with the other models apart from small variants and timing differences. This scenario is deja vu from last weeks saga re undercutting, so I don't expect it to be resolved till T-120. The ECM is one option, GFS control has another option as did the Parallel and the op.

 

At least we have sorted the big picture till around D9. Just the surface details to sharpen up on and they are very uncertain past D4.

[Skyraker]

ECMWF also showing the Low dropping S/E over the UK from the N/W.

 

That's going to be pretty unpleasant on the ground.

[492]

http://www.wetterzentrale.de/pics/brack2.gif

 

Latest  Fax at T+72 very similar to previous two runs although a bit of a better shape to the block with more of a hint of a continental flow into the SE. Colder drier air from Poland and further east now filtering into E Germany and E Denmark.   

[Gael_Force]

What a difference twenty four hours can make. It has been evident in the ECM ensembles, where ground temps for Saturday have been switching, run to run, from top of the range to bottom of the range.

 

 

[chionomaniac]

Could i ask you why?Thanks in advance

Yes - but the answer will be delayed until after the winter forecast!

[blizzard81]

The best analogy that can be used to describe the current output is England trying to do a penalty shoot out at the World Cup, just one miss after another!

 

A serious of opportunities where one slips on wet grass, the other blazes over the bar and the other hits the post!

 

The catalogue of misses one can correlate with the output, the shortwave that hangs around for too long, the ECM now has a less developed low over the USA and not enough interaction with the PV chunk etc etc.

 

The last vestige of hope is something alluded to by CS, which I will call the GOH Gap of Hope!

 

ECH1-144.gif

 

Either something develops here to add some forcing on the trough or its a one way ticket to mild especially as the more favourable upstream pattern shown by the ECM 00hrs hit the buffers.

Yes Nick, very well put again. The ECM tonight is an absolute shocker for coldies. At least it is not in it's usual teasing mood with promising charts far out.

 

The ECM is fast becoming the GFS which I used to deride frequently and is fast becoming King only upto T144hrs but a complete chump after that point.

 

So my fellow coldies its either the GOH or I fear my helpline will need a big influx of new telephone operatives!

[blizzard81]

And yet, amidst all the uncertainty, we have the higher res ops at day 9/10 (ec/gem/gfsp)  all taking a depression se without there being obvious resistance to it heading ne. as i said yesterday, it wouldnt surprise me if this depression ends up a bit further west by the time it tends se into europe. it could be an interesting european visitor. watch this space.

You and your big mouth. Unless ECM is an outlier of course.

[nick sussex]

Not an outlier but possibly a bit progressive. small. changes around day 7 are biggish differences by day 10

This might help I'm happy to report some more positive news after the mood deflating ECM:

 

From NCEP, lets hope these comments hold till tomorrow.

 

A VERY BRIEF PERIOD OF FLATTER MEAN FLOW DURING THE FIRST HALF OF

THE PERIOD... BRINGING A MODERATING TREND IN TEMPS TO THE ERN

STATES... WILL BE REPLACED BY AN AMPLIFIED MEAN TROUGH THAT SHOULD

REACH A GRTLKS TO SRN PLAINS ORIENTATION AS OF DAY 7 NEXT TUE.  AT

THAT TIME A STRENGTHENING UPSTREAM RIDGE SHOULD BE POISED TO ENTER

THE WRN CONUS.  THIS PATTERN/EVOLUTION WILL FAVOR HEAVIEST PCPN

OVER THE NORTHWEST AND FROM THE GULF COAST/SRN PLAINS NEWD.  MOST

ASPECTS OF THE LARGE SCALE FCST DISPLAY AVG TO ABOVE AVG AGREEMENT

BUT SOME SIGNIFICANT DETAIL UNCERTAINTIES EXIST.

Hopefully this carves more amplitude in that troughing to the west of the UK.

[knocker]

The last five days GEfs 12z anomaly running from T240.  There is little change in the last 24 hours with the impasse regarding the trough and HP.

 

Taking today''s run alone the progression from T144 -T240 shows a movement east of the trough and an extension south.

 

Charts courtesy weathebell.com

 

 

[nick sussex]

The Forecaster from NCEP comes up with this for T168hrs, of course it could change but that looks more amplified over the USA than the ECM horror show:

 

 

 

[ANYWEATHER]

As with the stalemate scenario over the Uk continues for a few more days, it looks like a ridge builds from the southwest very quickly late weekend and into the very early part of next week allowing for some frost and fog ,but quickly replaced by the Atlantic shown on both models which lately is unusual but shown at an unreliable timeframe. Both models show at later stages of there runs the Atlantic the winner, but its all speculation at the moment.....

[shaky]

The Forecaster from NCEP comes up with this for T168hrs, of course it could change but that looks more amplified over the USA than the ECM horror show:

 

9nh.gif

that's quite an area of high pressure in the atlantic on that chart! ! Cant see whether it ridges into greenland though! ! Does the ecm have a strong high like that in the atlantic at the same time nick?

[nick sussex]

that's quite an area of high pressure in the atlantic on that chart! ! Cant see whether it ridges into greenland though! ! Does the ecm have a strong high like that in the atlantic at the same time nick?

It's a difficult angle with those charts. The NCEP map is more like the GFS as its less progressive and a bit more amplified. Theres not much ridging into Greenland however.

 

That low is likely to phase with the one to the west of the UK, we still need however high pressure to the ne to try and force some of that energy to split more se rather than east.

[IDO]

that's quite an area of high pressure in the atlantic on that chart! ! Cant see whether it ridges into greenland though! ! Does the ecm have a strong high like that in the atlantic at the same time nick?

No that's just an Atlantic High running west to East towards the Azores, though it was a high over the eastern Seaboard for a few days. Just low heights in the N.Atlantic at that time scale. The amplification is current, till around D5, but this has been modelled to deamplify from around then, so it is the professionals view that ECM is too quick flattening the pattern and who are we to argue with that. With the Greenland vortex I am not sure any ridge can be sustained, so any changes will probably be measured in hours to maybe a day. Though there are timing issues compared to the GEM, so a possible wrong D8-10 again from ECM. Hard to believe, but they may be again wrong at that time scale!

[terrier]

Ok first things first the gfs run isn't great. yes the ECM is a horror show. But I urge people please look back a few pages to Tamaras great post. Plus old met mans post today. The polar vortex is nowere near as strong as last winter which we are seeing. It's only going to take further batterings from the warnings going on. And it's still autum meterologist winter is dec 21st so a long way to go yet. Give it time and our time will come. Hopefully we will see the models looking much better as we head later into dec.

[OldMetMan]

 

 

I would like to add a welcome to the return appearance of Old Met Man for the season - always much appreciated by many of us at this time of year

Thank you Tamara, I would like to thank you for your eloquent, well-reasoned and informative posts. You add great insight to this forum.

[knocker]

The ecm ens certainly more progressive east than GEFs or NOAA

Edited November 18, 2014 by knocker

[damianslaw]

Good post from Tamara - echoed by others - very suggestive of winter 12/13 conditions, where we saw trough disruption to our west and the UK sitting on the cold side of the jet with strong heights to the NE, (mind we did see a 4 week very mild very wet spell from mid Dec - mid Jan, something I wouldn't want to see repeated).

 

Based on model outputs and background northern hemispheric conditions, it does look quite probable we will see a return of the atlantic next week but a full sustained onslaught I doubt, perhaps a spell of wet fairly average conditions with trough/ridge development before a renewal of the current synoptic set up but the next round will be different thanks to a much cooler continent.

 

Late Nov/early Dec is the time of year least likely to deliver non-atlantic conditions, more often than not it is our most stormiest period of the year.

 

I'm expecting the models to stay firm with the atlantic pull next week, might be a good idea for colder lovers to refrain from looking at the models for a good 7-10 days, by then more promising fayre may well be on the horizon, and fayre more likely to deliver than recently.

[fergieweather]

 

Based on model outputs and background northern hemispheric conditions, it does look quite probable we will see a return of the atlantic next week but a full sustained onslaught I doubt, perhaps a spell of wet fairly average conditions with trough/ridge development before a renewal of the current synoptic set up but the next round will be different thanks to a much cooler continent.

 

Yesterday's output exhibited sufficient deep lows within EC and MOGREPS postage stamps for UKMO to caution (in their briefing issued last night) about some stormy conditions possible by circa D12. Similar situation evident from current suites - thus I think 'average' might not be guaranteed as terminology, but we shall see. Either way however, fair continuity now in the broader expectation for the return - one way or another - to mobility, perhaps characterised later by some vigorous depressions. 

[IDO]

Just to highlight the uncertainty re surface conditions for this weekend.

Similar to if we were in the depths of winter and there was a cold front heading east and hitting the block. The bigger picture has more confidence than the weekend's detail:

http://www.bbc.co.uk/weather/feeds/30105755

[bluearmy]

The ecm ens certainly more progressive east than GEFs or NOAA

Indeed knocker, naefs has trended in the direction of yesterday's ECM whilst ECM has done the opposite! One thing that frustrates me about the ECM suite is the way that the ens mean often follows the theme of the op. I'm sure we won't see such a progressive suite in the morning. Despite the modelling looking like its mobile, the mean upper features aren't moving much at all. as has been said again and again, if we are to be stuck in a rut at this time of year, the main features we have should be ok for cold in the months ahead via feedback mechanisms.