I know it's the Model Output thread, but sometimes there are non-NWP indicators that override what the NWP is saying. I remember in Nov 2010 and Darren (Retron) basically dismissing the evolution showing in GFS low res, and explaining his thought process. He was spot on. These days, we sadly don't have Retron posting (another great weather guy with a strong knowledge driven away by trolling dickheads, who IMO just resent the knowledge of people like Retron, Bren & Matt Hugo so snipe out of jealousy). Most of us can interpret NWP to a reasonable standard, but there are few with the ability to see trends & little nuances beyond what's in front of our noses.

These days, we have Stormchaser almost forensically dissecting NWP and adding his fantastic knowledge of wider influences at play, whilst people like Quantum add some valuable input also.

I think it's vital not to get overly hung up on individual output runs.

MOGREPS is about as important as models get regarding the UK's weather. We're talking about the vast ensemble suite that weighs in heavily on the Met Office forecasts.

Sure, it's far from infallible, with this -ve NAO theme only a recent development after what was a very flat outlook out to around day 15, but this trend is fitting with that many following strat. and MJO developments have long anticipated later this month (or early next for the major stuff), which is why it really catches my eye.

The most important line in the comment by Fergie is the one which proposes that current NWP output may not be adequately capturing the broad scale pattern evolution, which suggests that lower-res GFS should be viewed very skeptically at the moment, and perhaps ECM's day 9-10 output too, though that's right at the near-end of the period of uncertainty being discussed.

Right on cue, it's good to read that the 00z EC ensembles also show signs of the westerlies abating in favour of blocking highs. The continental block would not directly bring about a -ve NAO though - we'd need low heights in the Atlantic or over the UK to then start slipping away S or SE for that. Such sliding lows are notorious for being missed by the NWP output at 7-16 days range.

Obviously the trend could about-face and leave us locked into the same pattern for a fortnight or more, so many more runs are needed before expectations can be allowed to drift towards something more substantial in terms of a UK cold spell.

LOL - i saw a report that there will be some data missing on Boxing Day... boat in the wrong place, so that's a worry 

Hi Martin, I had wondered where Darren had got to, that is a shame he has left.

It is, but at the same time he left because he was annoyed by someone's (remain nameless) summer LRF forecast. To be honest I've no time for either. It's just a weather forum.

im equally bored of Saint dredging it up every two minutes. Further off topic posts will be deleted. 

We are where we are.

Nowadays Gibby does a very good balanced assessment each day not that dissimilar from Darrens efforts.

James is far more analytical but nonetheless very interesting.

Whilst others chip in, these guys are the players in here and the ones I read first in the thread.

Keep up the good work

Great, a Euroslug to write off another month of winter

I didnt  realise Retron had gone, shame. Hope Steve Murr is still around

Fits in with last night's Countryfile forecast, which closed on the throwaway line "the following week and into the next weekend looks colder than average" - I wondered what he might be alluding to and the above chart (if it verifies) shows the line of reasoning.

Again sorry if this isn't clear, I'm still getting used to the graphics. I downloaded an excellent colorbar script though that makes it legible now. Anyway here is a full world view of the 500hpa heights at 90hr.

This is as good as it gets at 90hr with heights rising over greenland. The 552 isopleth just reaches, again even if this is only temporary I think its a good sign to maintain it as long as possible. In general if you compare the northern polar front with the southern polar front you can see the former is really becoming disturbed; note the southern polar front is a good reference because it never becomes that disturbed due to a lack of friction from large continents America and Eurasia. I think the outlook is actually pretty optimistic at the moment if I'm honest, which is why I think the mood in here is rather odd; it certainly isn't the hair tearing output it was during the 2nd part of November. I think there is a very good chance of a reload beyond the end of hi res.

Indeed

Hopefully a timely interjection, but UKMO caution (again) that medium range NWP may not be adequately reflecting ultimate broadscale outcome. First tentative signs emerging, they suggest, of *possible* pattern change (weakening of MSLP anomaly; transition to -ve NAO) second half/later December, with GloSea5 continuing to yield interesting stratospheric signals later this month. So, without wanting to sound like a stuck record, I do urge 'elasticity of thought' when assessing distant reaches of EC/GFS suites.

He quotes the DC

Let me cite the Deputy Chief directly (from briefing issued this morning, based on 00z suites), to clarify exact phraseology:

"....postage stamps from both EC and MOGREPS-15 are now showing some waning in the strength of W’ly progression, with a minority of members (~40%) hinting at blocking across the Continent".

500mb heights and their anomalies in the style of the charts Gav uses in his weather vids all the time. Again for 90hrs which I think is an interesting point.

I think its fairly promising, warm colours over Siberia and more importantly E canada. Blues carried towards scananavia by the midweek storm. But this is definately an improvement over huge amounts of blue over the baffin bay and the infamous polar vortex centre, baffin island.

Even more potent on the UKMO at +120

http://www.theweatheroutlook.com/twodata/datmdlout.aspx

The GFSP12z is running this afternoon.

Thanks for the heads up Brian 

what an odd little feature that warm air is over the tip of greenland...

Running through the charts it appears out of thin air.

Must be either warmer ocean waters - or falling warm air from aloft.

Let's all have a group hug 

Still a slim chance of some wet snow/wintry mix towards the end of the week, like I said the other day the GEFS has shown this for almost two weeks to be fair to it  http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

An interesting 24hrs to come I feel in terms of what the models show  could be a touch of everything thrown at us, Wind, Rain & Slush  

If anyone doesn't find it an interesting week then maybe they should retire from the threads

There is the chance of snow again especially but not exclusively for northern hills especially on Wednesday night/Thursday morning & with strong winds there could be blizzard conditions from the Pennines northwards. Looks like a very interesting period coming up. Certainly not boring.

Round 2 looks a lot better for those further south

http://modeles.meteociel.fr/modeles/gfs/runs/2014120812/gfsnh-0-240.png?12

Lots of cold air coming in from the Atlantic. Should be good for generating wintry showers for the usual suspects

http://modeles.meteociel.fr/modeles/gfs/runs/2014120812/gfsnh-1-300.png?12

Setting up for a White Christmas?

http://modeles.meteociel.fr/modeles/gfs/runs/2014120812/gfsnh-0-384.png?12

Yes Beast, interesting to see where/ what would happen to that low at mid latitude coming off the Eastern seaboard. With the North Western Atlantic looking completely blocked on Christmas Eve, it leads the imagination into all sorts of territory.

http://jpwxcharts.blogspot.co.uk/2014/02/blog-post.html

Me to ive learnt a lot from this forum still don't quite understand the dam lines though!