Model Output Discussion 17th Dec.2013-12z onwards.

[SMU]

Well the GFS is still after a promising start, a country mile away from the Euros, because of the fail last month Ive got to give it some credit, but some days its so painful watching it V the UKMO & ECM.

 

http://www.youtube.com/watch?v=WNIrs8FgYKU My thoughts on the GFS most days.

 

S

[That ECM]

Very interesting day of output. IMO it's best at times like this to watch with interest. Sometimes you can look at output and have a good idea in 6 plus days. Sometimes there are many options on the table and this, I feel, is one of those times.

[Barry12]

Crewecold has promised us that January will be severely cold, so no need to worry

Edited December 26, 2013 by Barry95

[karyo]

Crewecold has promised us that January will be severely cold, so no need to worry

Xmas promises don't count! He probably had a few sherries before hand. 

 

Karyo

[Ali1977]

P18 is a proper beast from the east from T204...that woul bring really cold weather

[Cheshire Freeze]

Xmas promises don't count! He probably had a few sherries before hand. 

 

Karyo

 

A bottle of wine to be precise......haha

[Ali1977]

If p18 happened this place would go into melt down, proper big freeze...

[SMU]

http://modeles.meteociel.fr/modeles/gens/run/gensnh-6-1-372.png?18

 

A proper Beast with -28c moving west over central Europe.

 

Ensembles will be interesting...

 

S

[Mucka]

 

Slowly, slowly...

[Panayiotis]

Well the high res NASA model at only D5 is looking great!

[draztik]

 

Slowly, slowly...

 

by the time it gets here, winter will be over...

 

Im clearly living on a different planet, but I am not seeing reasons for optimism (if its deep cold you're after).. I think It may be in the definition of cold. Cold to me, means minus values during day time. I don't see those kind of values in any recent output. The updated ec32, does not build heights over Scandi anywhere near the degree of the 12z op of earlier. While maintaining lower heights over us, to our NW, and for a while into Europe - before the signal recedes somewhat. We are left with a pretty unsettled picture throughout January, with at best below average values - but deep cold? Cant see it.

Edited December 27, 2013 by draztik

[ukpaul]

Ice days, where temperatures are below zero during the day, are so rare that you are lucky to get a handful even in northern areas. In Bristol you are basically saying that it would only ever be 'cold'  for around 1% of the year, which is crazy.

[Cheese Rice]

Ice days, where temperatures are below zero during the day, are so rare that you are lucky to get a handful even in northern areas. In Bristol you are basically saying that it would only ever be 'cold'  for around 1% of the year, which is crazy.

That's not true many northern cities like Sheffield or Leeds regularly see ice days during cold spells.

[Panayiotis]

Cold for me is when snow is falling from the sky. JMA is a nice chart at 192hrs which would deliver these kind of conditions to parts of the UK.

Edited December 27, 2013 by Panayiotis

[IDO]

No surprise ECM has backed off last night's 12z. However it has now gone the opposite direction with a flat zonal fest for T240:

 

 

Funny enough GFS op now has the faint Scandi upper ridge at T240 (that the ECM 12z was hinting at), and now sends the Arctic High towards that ridge, when yesterday it was sending it to the Pacific:

 

 Ditto the Control: 

 

However by D10 we are still hunting for a pattern, let alone getting the cold uppers in the flow.

 

Both GFS O/C end up with a Russian High and although there is amplification, nothing by D15 that will bring sustained cold.

 

The GEFS clusters are a step back and more in line with the Christmas Day output: 

 

70% back with a zonal flow though 45% points of that have the south in a slacker higher pressure flow.

 

GEM keeps the faith (T240): 

 

That has the Pacific Ridge/Arctic High linkage. So by the looks of it a greater chance of a surface trough over the UK with that combo.

 

For instance from the GEFS:   

 

They are back in the minority now. More runs needed as inter model and cross model wise there is much disparity.

Edited December 27, 2013 by i'm dreaming of...

[shedhead]

shedhead, on 26 Dec 2013 - 17:51, said:

there is still no sign of a colder pattern emerging, with max temps remaining near or a little above average for the bulk of the UK well into January.  

 

 

 

 

bluearmy

charts please shed ?  both your statements are incorrect.

 

Here you go ba. Not really sure how my statement above is incorrect on both counts.

 

 

 

[bluearmy]

Chaing deep cold will inevitably leave you disappointed in the UK. In January, we really don't need deep cold to deliver ice days and sustained snow cover. Tbh, we don't need ice days anyway, as long as dp's are sub zero.

On the gefs, runs 4 and 9 post T192 are where I was expecting the modelling to go. I am a tad perturbed by the current trend re the Azores ridge in the mid range on the gefs (and some ops). tbh, I am expecting a bit of a shift in the extended ECM ens this morning away from their bullish euro trough fed on a track through the UK (although the ec32 is well inline wit their consistent output to day 16). A more thorough look through the ens after 9am and a post to follow.

Thanks for those charts shed but 6th jan = well into jan ? And the final frames show a retrogressing Azores plus developing Svalbard ridge. Your statements were just too definitive, given the extended ens.

Edited December 27, 2013 by bluearmy

[Duane S.]

All models firming up on the ridge pushing SW into Greenland. I think that event alone should provide us with interest in the coming days as it ought to offer a veritable smorgasbord thereafter. We do have one powerful vortex however that will want to make the audacious gatecrasher pay for its actions but at the same time I'm not convinced it is simply going to overpower heights being fed into the Greenland locale too quickly. The presence and location of the AH in low res is a bit concerning but I do feel the GFS has the better handle on it as it sending energy SE and pressure over Mid Europe deepens

 

I think the we are going to see the ops play around at quite a few different scenarios for around the end of the 1st week of January mark in the coming days.

[Uncle_Barty]

 

shedhead, on 26 Dec 2013 - 17:51, said:

 

 

bluearmy

charts please shed ?  both your statements are incorrect.

 

Here you go ba. Not really sure how my statement above is incorrect on both counts.

 

 

If Shed had added the word "consistent" somewhere, then he really would have been spot on.

 

There are NO consistent signs of a change to the pattern being shown by all the models in the 7-10 day timeframe, and until there is, then a continuation of current conditions, albeit perhaps less severe then they have been, looks to be an absolute banker.

 

I do concede that things can change very quickly, and that come the end of the first week of January, we might be looking down the barrel of a significant cold spell. But there is nothing consistent to suggest that now. I do not call picking out odd perturbments at t+204 a consistent sign!

[Weather-history]

http://www.meteociel.fr/modeles/ecmwf/runs/2013122612/EDH0-240.GIF?26-0 ECM MEAN tonight very good at 240- also from day 9 to 10 the cold over Europe advances west which it cannot do unless its being forced, also this wouldn't be the case if there is no block. All in all a good day for the euros. S

I looked at this post yesterday and even now I still don't get why the ECM mean you consider very good? There isn't a hint of the mean of the ensembles suggesting a block over Scandinavia in that chart to me and it shows Icelandic low and a ŵesterly flow over the UK. I would have thought a very good ECM mean would show some indication of blocking over Scandinavia?

[Gibby]

Good morning. Here is the reports on the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday December 27th 2013.

 

All models show a deep depression to the NW of Britain today moving slowly away North over the next few days but maintaining a showery Westerly flow over the UK with some of these falling wintry in the North. Strong winds will slowly moderate. By Sunday a new Low brings further fronts NE with rain in tow for all areas and further strong winds. The pattern then continues up to the New Year with all models showing rain bands mixed with showery interludes in basically quite strong SW winds and average temperatures.

 

GFS then shows New Year celebrations taking place under windy and often wet conditions with SW winds continuing to blow and maintaining average temperatures. Then as we move through Week 1 of 2014 and into Week 2 little change is shown with Low pressure continuing to race over the Atlantic over or to the North of the UK with spells of rain alternating with brighter and clearer spells with showers, wintry on hills in the North.

 

UKMO ends it's run with the chart for next Thursday showing Low pressure over the entire North Atlantic with one small and vigorous centre moving NE then North up the spine of Britain bringing more wet and windy conditions well into the New Year.

 

GEM today shows very unsettled weather under deep and complex Low pressure to the North then over the UK before sliding it SE late in the run towards NW Europe. There would be spells of wet and windy weather with showery spells intermixed. With time the air would turn colder with wintry showers for many by Day 9 before a toppling ridge from the Azores High gives a quieter interlude before new Low pressure steams across the Atlantic towards Britain soon after the end of Day 10.

 

NAVGEM shows Low pressure out to the NW in the first few days of 2014 with a strong WSW flow bringing spells of rain and strong winds across the UK throughout.

 

ECM today shows a wet and often windy start to 2014 too with just relatively short drier spells as ridges attached to an Azores High cross the UK for a day or two in the first week before by Day 10 the chart looks like the UK could be staring down the barrel of another very wet and windy period with Westerly gales.

 

The GFS Ensembles show very stubborn resilience to any form of change from an Unsettled Atlantic based pattern with rain at times and temperatures close to the long term mean for areas North and South of the British Isles.

 

The Jet Stream continues to trek across the Atlantic Ocean in the general direction of the British Isles for the foreseeable future. It does shift briefly South at times allowing trough to dig deeper down over the UK but not sufficiently so on this morning's output to offer any form of pattern change by encouraging any meaningful High Level blocking to the East and NE to affect the UK anytime soon.

 

In Summary the current pattern is maintained this morning with spells of wet and windy weather alternating with spells of slightly colder weather with sunshine and showers. Temperatures look like staying largely close to average over the next two weeks but that doesn't exclude the odd colder interlude from polar maritime incursions giving some snow on Northern hills at times. Overall the prospect of any cessation of this powerful Atlantic train anytime soon remains low with an unsupportive Jet flow orientation and strength coupled with the resulting ever present High pressure belt well to the South keeping a strong Westerly flow over the Atlantic towards the UK.

[IDO]

 I hope Fergie does not mind but his recent tweet is quite insightful:

 

  fergieweather
Tentative signs of some changes to broadscale story later through Jan as number of MOGREPS & EC members offer E'rly types with low to Biscay
27/12/2013 08:30

[weather eater]

If Shed had added the word "consistent" somewhere, then he really would have been spot on.

 

There are NO consistent signs of a change to the pattern being shown by all the models in the 7-10 day timeframe, and until there is, then a continuation of current conditions, albeit perhaps less severe then they have been, looks to be an absolute banker.

 

I do concede that things can change very quickly, and that come the end of the first week of January, we might be looking down the barrel of a significant cold spell. But there is nothing consistent to suggest that now. I do not call picking out odd perturbments at t+204 a consistent sign!

While recent runs have suggested that there is now more to be optimistic than there was a few days ago in terms of getting the pattern most would like to see, I would agree there is nothing consistent showing for a real pattern change and the form horse still appears to be a continuation of the current vigorous Atlantic regime, although slightly less vigorous than recent days, hopefully this will change in the next few days.

[garbagebags]

While recent runs have suggested that there is now more to be optimistic than there was a few days ago in terms of getting the pattern most would like to see, I would agree there is nothing consistent showing for a real pattern change and the form horse still appears to be a continuation of the current vigorous Atlantic regime, although slightly less vigorous than recent days, hopefully this will change in the next few days.

 

I disagree. The pattern is looking to change in FI. To what, it's not sure, how, it's not sure but higher pressures to the north and lower to the south seem to be the key movement. The "form horse" is definitely not continuing vigorous Atlantic. 

[IDO]

That ties in with the ECM mean at T240: 

 

The s.Euro upper trough remains consistent. The surface pattern still has the flow from the west riding over the trough (hence signs of the AH ridging in), with a cut off mean low in s.Euro. We need a trigger to divert the surface flow SE and that I presume will draw in the colder uppers and then reinforce the mean upper Scandi ridge. The pieces are seemingly in place for a cold spell and with the upstream amplification forecast for the US, this could trigger the Canadian vortex energy SE and get things moving.

 

Second-Third week January potential maybe.

Edited December 27, 2013 by i'm dreaming of...