Model Output Discussion - 8th December Onwards

[Gavin Hannah]

I think that's why we only get two days ahead max in the Beeb forecasts. And on the Countryfile update, at day 5, Susan was stressing how things could change to what she was presenting.

What I think will be a big factor on the potential outcome as we enter this week is the Snow cover atm.

The European cover is just epic.

Edited December 9, 2012 by IBringTheHammer

[Polar Maritime]

Isn't there always change in a forecast 3/4 days out... never mind 8+ days,. same as the models, every forecast i have seen today has very low confidence after thursday, which does not come as a surprise lately after following the models over the last 2 weeks...

Edited December 9, 2012 by Polar Maritime

[pyrotech]

I didn't think the UKMO put out High confidence assessments for Day 8+.

I think Ian would be best to ask how they are confident in that timeframe and for it to be cyclonic.

I would expect it is from the series of runs by EC showing a trend, but with the adjustment in the trend maybe it will change, but that speculative from me.

It could even be that one senior forecaster sees a trend forming in the big picture, but another one will see the opposite.

Could also be that they have something a little extra in the data that we do not, certainly not the time now to see if its right or wrong, we can discuss that on xmas day and after.

I must say i am surprised to see confidence high in that timeframe, would of expected moderate at best with current models evolving perhaps to less zonal.

Perhaps todays senior forecaster is a big netweather user, and loves watching us throw our toys out of the pram ..... or wants xmas to be a nice surprise

Sorry since posting have seen Ians reply posted above via someone, but i think the above does reflect it somewhat

Edited December 9, 2012 by pyrotech

[Zenarcher]

ECM has good support from it's pressure ensembles more than half of them show the Atlantic weather being weaker like what the models have suggested recently. There still seems to be disagreement over the low that was shown on last nights 18z GFS, the ECM and GFS send it across the far South of the Atlantic and make it go into Europe and fizzle out but the UKMO shows it at 144 hours to head straight into the Atlantic.

[Welsh_Weather]

Hi quote from UKMO via Ian Fergusson:

Days 8-10, Sun-Tues: Unsettled and often windy with bands of rain crossing the UK, with clearer/showery interludes in between. Still a risk of some snow over high ground at times in the N, mainly Scottish mountains. Temperatures mainly close to average, occasionally mild in the S, but with still a risk of overnight frost in clearer, quieter interludes. EXTREMES COMPARED TO CLIMATOLOGY: Nil CONFIDENCE: High confidence for cyclonic SW’ly type. Low to medium confidence for the heaviest spells of rain to be across the S and W.

Days 10-15: broad continuation of conditions and synoptics described above with little change expected."

Yes they do.

I have a lot of respect for Ian Furgusson but didn't he have high confidence in an extremely cold and snowy spell just a few days ago? No one can have high confidence in any outcome after Thursday at the moment. Less than 24 hours the models were suggesting the Atlantic steaming in on Wednesday now it's been pushed back 2 days.

I still think the Atlantic will win out on this occasion but I really cannot see a zonal stup with the PV setting up over Greenland between now and Christmas.

And btw I was looking at the UKMO forecast without Ian's input.

Edited December 9, 2012 by Welsh_Weather

[Summer Sun]

I think that's why we only get two days ahead max in the Beeb forecasts. And on the Countryfile update, at day 5, Susan was stressing how things could change to what she was presenting.

What I think will be a big factor on the potential outcome as we enter this week is the Snow cover atm.

The European cover is just epic.

This is the second big freeze to hit a wide part of Europe this year last time we got the tail end of the cold which resulted in the years coldest temperature so far of -15.6°C at Holbeach (Lincolnshire) on the 11th of February, this also broke down to a mild westerly with a high of 18.7°C recorded after the cold spell ended

Edited December 9, 2012 by Gavin.

[Gavin Hannah]

ECM has good support from it's pressure ensembles more than half of them show the Atlantic weather being weaker like what the models have suggested recently. There still seems to be disagreement over the low that was shown on last nights 18z GFS, the ECM and GFS send it across the far South of the Atlantic and make it go into Europe and fizzle out but the UKMO shows it at 144 hours to head straight into the Atlantic.

The 06 also had it pep up over the channel and take an undercutting route. Leads me to believe the 18Z and 06Z are tracking the same idea.

[OldMetMan]

'Morning OMM. You could well be right about that. What are the odds against any particular digital solution being the right one, do you think?

Don't know the history behind yesterday's thread, though - I was away in the Land of Nod, by then...

Hi Rybis, sorry I missed this one earlier!

I think I will most likely put my trust in the Met FAX charts when we are nearer the time but I doubt even they will be all that accurate. It's a very tricky forecast to have to make but, as far as plain computer output is concerned, I would most likely put more faith in the GFS and also the GEM as being nearest the mark - notwithstanding my reservations from yesterday.

OMM

Edited December 9, 2012 by OldMetMan

[IDO]

I have a lot of respect for Ian Furgusson but didn't he have high confidence in an extremely cold and snowy spell just a few days ago? No one can have high confidence in any outcome after Thursday at the moment. Less than 24 hours the models were suggesting the Atlantic steaming in on Wednesday now it's been pushed back 2 days.

I still think the Atlantic will win out on this occasion but I really cannot see a zonal stup with the PV setting up over Greenland between now and Christmas.

And btw I was looking at the UKMO forecast without Ian's input.

Hi the quote is not from Mr Fergusson per se, it is the comments made by the UKMO forecasters from one of their two(?) daily meetings. He is just kind enough to pass these details on to help us try and work out what's going on. They are obviously not Gospel but are made in good faith.

Edited December 9, 2012 by i'm dreaming of...

[SMU]

Afternoon All-

just before the 12's set out- a quick post from me- & comment on the last few days-

It was disapointing to here that Ian has decided to leave the model output, so I thought I would put a few lines together to hopefully clear the air even though I hadnt seen what was posted that day.

I think everyone would admit that having Ian on board in the model discussion is invaluable, what I would like to highlight is the most valuable elements,--

As I guess most have -Ive really enjoyed the snippets & the odd chart thrown in from Exeter in the sub 24/36 hour analysis-

We all have visibility of charts at X hour- however what some miss & nearly all could learn from is real indepth commentary of charts that show us where the real business end of forecasting goes on, the positioning of frontal zones, the particular influences & rates of changes within the columns of the air up to the cloud base, convergence zones etc etc - I feel that level of data is certainly something that raises the enjoyment of the forum away from some of the mundain day to day ways that things are presented here.

So Ian thanks for that--

What perhaps I felt was slightly 'misjudged' is the assessment that because we show emotion & bias towards a particular outcome that perhaps some of us are less of a fan of weather than maybe those that show equal 'like' for all types of weather-

At some point in our lives we all enjoyed a weather event or soemthing struck us that the weather was enjoyable - which lead us here- on a forum to discuss our interests- just because we didnt actually persue a career in this area- doesnt mean to say our enthusiasm isnt there-

I think everyone on here understands ( or should ) that the objective of a professional forecaster is to get accuracy as good as possible & convey that message in the clearest way, its clear that the way the MET / BBC are going is that in this day & age there is no room for bias or emotion towards a particular outcome- & thats why I believe personalities like Rob Mcelwee have been slightly snubbed in favour of more clockwork forecasters-

Im sure that what you provide through the connection with the met office kerbs the en-mass emotional approach to forecasting that we 'generally' adopt in Winter, its very hard to remain objective when forecasting or reviewing on here because there is no accountability to anyone who gets it wrong or forecasts an event that doesnt happen however close or wide of the mark.

I think there is room for it all though, right from the down the line scientific analysis with bound forecasting measures to the everyday hobbyist who comes on here posting their interpretation of the models & what they think is going to happen-

Im sure everyone appreciates that you cannot be drawn into deep discussions or leading questions around preference & maybe some shouldnt ask to avoid tricky situations, but on the whole its a great blend here & hopefully you feel that your contributions are valued- as they are.

This winter is only 9 days old, however most of us have been entrenched in the model threads for the last 5 weeks - this has been a typical Winter on net weather so far ( for those newbies) Big rollercoasters - highs & lows- dispair right through to excitment-

No matter how much we love to hate it sometimes you can bet your bottom dollar though that just as the senior forecasters & team are sitting down at the Met to start reviewing the 12z UKMET data & MOGREP data then everyone that contributes on here will pulled to their PC's like a tractor beam at around 3:29 today when the GFS & UKMO start to roll out....

Par for the course.

[Polar Maritime]

Hi the quote is not from Mr Fergusson per se, it is the comments made by the UKMO forecasters from one of their two(?) daily meetings. He is just kind enough to pass these details on to help us try and work out what's going on. They are obviously not Gospel but are made in good faith.

As always they are made in good faith, and subject to change, but more so than ever in this "set up".

Edited December 9, 2012 by Polar Maritime

[Gael_Force]

I have a lot of respect for Ian Furgusson but didn't he have high confidence in an extremely cold and snowy spell just a few days ago? No one can have high confidence in any outcome after Thursday at the moment. Less than 24 hours the models were suggesting the Atlantic steaming in on Wednesday now it's been pushed back 2 days.

I still think the Atlantic will win out on this occasion but I really cannot see a zonal stup with the PV setting up over Greenland between now and Christmas.

And btw I was looking at the UKMO forecast without Ian's input.

I don't think this was the case; he said the MOGREPS were showing southerly/S.westerly solutions but that MO favoured the ECM suite. Not sure if MOGREPS swung round to cold easterly later - did not see comment to that effect.

[Methuselah]

Soooo!! It's nearly time! What will the 12Z say, this time? Will the Russian Bear sweep westwards with mighty roar?Or will the Atlantic depressions produce an audacious last-minute flanking manoeuvre, and derail the White Army's advances?

Who knows! Lets get ready to rumble!

[Gavin Hannah]

Soooo!! It's nearly time! What will the 12Z say, this time? Will the Russian Bear sweep westwards with mighty roar?Or will the Atlantic depressions produce an audacious last-minute flanking manoeuvre, and derail the White Army's advances?

Who knows! Lets get ready to rumble!

I'm thinking the 12Z will get on board with the 18Z and 06Z..... (It's my preferential gut feeling driven by my emotional need for epic wintry weather.)

[Summer Sun]

Another from Ian in the south west thread

Key thing from Exeter is how no model in their suite exhibits any signal for what they characterise as 'disruptive' snow into Friday, with transient snow signal strongest from Wales-Midlands northwards. However, of greater significance is the strong signal for 10-30mm rain widely, which needs close monitoring as we approach the event.

Incidentally: Snow early this week in the E looks very restricted now in latest output from UKV etc: profiles show winter Cb's but these staying offshore in N Sea with no favourable gradient to bring them much onshore (if at all), whilst coastal development expected as some TCu's so some moderate snow showers at times.

Thereafter, expectation remains for a continuation of a broadly cyclonic Pm pattern towards Christmas, with a rather cold signal (inevitably) throughout and further potential for wet/windy phases; snow potential remains greatest Midlands N'wards but with transient risk elsewhere.

[ChartViewer]

Were so close come on snow spreads West this week!!!

[Summer Sun]

Were so close come on snow spreads West this week!!!

This cold spell snow cover is not to dissimilar to the last cold spell in February

could someone -plz tell me last winter when the block finally affected our weather in some way in February was it in early feb or later i cant remember the right time period.

It was the first 2 weeks for the UK eased after mid month with mild westerlies taking over

Edited December 9, 2012 by Gavin.

[leemondo]

Were so close come on snow spreads West this week!!!

it looks like everybody in the UK needs to go west for a swim and push our island a few hundred miles east!

I'm utterly fascinated by this winters modles, up's and down's, although i cant really read them i love all the opinions being made, and also the fact that this thread has calmed down and leveled out now is an added bonus, was getting way out of hand, and i think the mods have done a fantastic job, thank you all

[Frosty.]

Isn't there always change in a forecast 3/4 days out... never mind 8+ days,. same as the models, every forecast i have seen today has very low confidence after thursday, which does not come as a surprise lately after following the models over the last 2 weeks...

Yes PM, there is hope today where there was no hope yesterday, the models were adamant of a swift transition to milder air by thursday as the lows pushed in more from the west to east but overnight the models have been thrown a curve ball and are now looking at a different angle of attack which would increase undercut and therefore increase the chances of a big dumping of snow for at least central and northern parts of the uk later in the week, and who knows, perhaps the fronts will stall and be forced south again on subsequent output. I think there could be a good fight between the milder atlantic and the cold block in the next 5 days and the current outlook might need a rethink pretty soon.

[Panayiotis]

The first chart was published exactly last week and it shows what this Mondays weather couldve been, the second image is what the 06z is showing for Manday(very likely to verify) from this you can easily see why we shouldnt look beyond 4-5days but the trend has stayed and that was the ridge into Greenland or close to Grenland.

Edited December 9, 2012 by panayiotis

[Polar Maritime]

Yes PM, there is hope today where there was no hope yesterday, the models were adamant of a swift transition to milder air by thursday as the lows pushed in more from the west to east but overnight the models have been thrown a curve ball and are now looking at a different angle of attack which would increase undercut and therefore increase the chances of a big dumping of snow for at least central and northern parts of the uk later in the week, and who knows, perhaps the fronts will stall and be forced south again on subsequent output. I think there could be a good fight between the milder atlantic and the cold block in the next 5 days and the current outlook might need a rethink pretty soon.

Aye Karl, these battle-ground set up's can and do bring last minute surprises, as we have seen in the past.

[CanadaAl]

Already at T+24 showing strong high over greenland and low a touch further west. Exciting times!

[IDO]

Yes PM, there is hope today where there was no hope yesterday, the models were adamant of a swift transition to milder air by thursday as the lows pushed in more from the west to east but overnight the models have been thrown a curve ball and are now looking at a different angle of attack which would increase undercut and therefore increase the chances of a big dumping of snow for at least central and northern parts of the uk later in the week, and who knows, perhaps the fronts will stall and be forced south again on subsequent output. I think there could be a good fight between the milder atlantic and the cold block in the next 5 days and the current outlook might need a rethink pretty soon.

Yes, the ensembles have been consistent the last few days with 15-25% support for the breakdown to be subdued and colder uppers maintained. You would have thought as we get closer to higher-res this would not be the case. So its no where near a no-hoper, very plausible. If we can get those up to 35-40% by the end of today's runs then it will be an interesting Mon/Tue model watching. The spread at T120 confirms this:

[Gavin Hannah]

The first chart was published exactly last week and it shows what this Mondays weather couldve been, the second image is what the 06z is showing for Manday(very likely to verify) from this you can easily see why we shouldnt look beyond 4-5days but the trend has stayed and that was the ridge into Greenland or close to Grenland.

The 12Z is even closer matched for Monday.

[Damp and dreary]

Hi quote from UKMO via Ian Fergusson:

Days 8-10, Sun-Tues: Unsettled and often windy with bands of rain crossing the UK, with clearer/showery interludes in between. Still a risk of some snow over high ground at times in the N, mainly Scottish mountains. Temperatures mainly close to average, occasionally mild in the S, but with still a risk of overnight frost in clearer, quieter interludes. EXTREMES COMPARED TO CLIMATOLOGY: Nil CONFIDENCE: High confidence for cyclonic SW’ly type. Low to medium confidence for the heaviest spells of rain to be across the S and W.

Days 10-15: broad continuation of conditions and synoptics described above with little change expected."

Yes they do.

Was this taken from today or yesterday though? Just wondering if these 'slight' model changes have made any difference to the M.O outlook?