General Model Output Discussion

[kold weather]

Whilst the GFS is keen on bringing in the Atlantic, and its a trend that I think has got some merit, much depends on how it all evolves and whether the big LP in the Atlantic cuts-off. If it does then the Atlantic won't come in because the position of the PV will allow a ECM set-up where we keep a Scandinavian high in place.

I the low doesn't cut off, then it will lift a shortwave over the country, big snow event but it will eventually come up one way or the other...

Its a toughie, it is going to become less cold eventually but we should not think the Atlantic is just going to roll in, because I find that very unlikely if I'm honest, this will be a tricky evolution to nail...

[Mark Bayley]

If anyone wants to view the 850hpa temps for the ECM they can here

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/ecmwf/archiv/NSea/thgt850/2010010612/nothumb/ch/a0f0bd4d40.html

Shows the 850hpa's staying around -2c to -3c as the low passes before the -5, -4c 850hpa temps return towards the end

[Severe Siberian icy blast]

ecm is really the only model that is trying to hold on to the cold,

and i agree its not been the norm type of winter with last winter to being fairly full of blocking to but unless all models agree on something similar to each other then id back a breakdown.

i also noticed alot of post regarding this weekend easterly being a downgrade this does not seem likely from what im seeing,

very confused though bbc south weather and meto warning of possibliy more prolonged snow on sunday here in the south,

i dont understand how?

The reason been is a number of reasons .

-10 uppers penetrating the country over the north sea bringing convection in from the east .

As its a strong easterly rather than a slack north easterly the showers will penetrate well in land .

As theres low pressure in europe which is our source there will be troughs/disturbences with in the flow .

P.s . . . I think this could be what countryfile hinted at on sunday , which origonaly they thought would be friday , although as early as tomorrow there is the potential for snow from the east coming in land .

[nick sussex]

The shortwave holds the key this evening at 168hrs, if it verifies on the ecm then this will determine where the rest of January goes, the gefs ensembles show a clear split but the ecm operational run takes this under the block and prolongs the cold.

The gfs operational run decides to go the predictable route in it's lower resolution model output by ending the cold with the Atlantic winning, so which model do you believe this evening. To be honest anyone calling an end to the cold has to believe that the gfs is the one to follow in European blocking patterns, which is definitely not where i stand, the gefs ensembles actually have more colder solutions this evening and the gfs operational runs have been constantly criticized by forecasters in the USA, NOAA have generally followed the ecm and it's ensemble mean.

IMO the gfs will backtrack as it has basically done so for the last few weeks and will fall into line with the ecm/ukmo . So no end to the cold with more significant snow for eastern and se areas, also the chance for a Channel low.

Edited January 6, 2010 by nick sussex

[kold weather]

Just seen the ensembles for the GFS, not exactly a convincing case for the breakdown, many are still cold through surface flow, some are actually cold are depth (through another easterly) the rest go for a similar 12z op solution...but even then probably half of those rebuild in the cold again...

So right now I'd say it really is 50-50, the Atlantic will try and force its way back in but as some of the older members should remember, once you've got these set-ups in place they can be very stubborn and easily able to come back.

[Cecil Hogmanay Melchett]

Just seen the ensembles for the GFS, not exactly a convincing case for the breakdown, many are still cold through surface flow, some are actually cold are depth (through another easterly) the rest go for a similar 12z op solution...but even then probably half of those rebuild in the cold again...

So right now I'd say it really is 50-50, the Atlantic will try and force its way back in but as some of the older members should remember, once you've got these set-ups in place they can be very stubborn and easily able to come back.

Great post Kold,we have a bitter easterly sat/sun,after that we simply don;t know.We come desperately close to a breakdown on ecm but even if it does happen it wont be until wed/thu next week meaning another 7 days at least of bitterly cold weather.

[sebastiaan1973]

I have the temperatures for De Bilt for you, based at the ECM run 12

7: -3/-5

8: -3/-7

9: -1/-5

10: 0/-1

11: +1/-2

12: -1/-2

13: -3/-5

14: -3/-6

15: -4/-7

16: -5/-9

[TEITS]

If anyone wants to view the 850hpa temps for the ECM they can here

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/ecmwf/archiv/NSea/thgt850/2010010612/nothumb/ch/a0f0bd4d40.html

Shows the 850hpa's staying around -2c to -3c as the low passes before the -5, -4c 850hpa temps return towards the end

Thanks for the link.

I imagine come next week as we pull in less cold uppers from the E then E coastal regions could actually see a thaw due to the warming effects of the N Sea. If a LP does track to the S then I believe only inland locations are at risk.

Like I said earlier the ideal solution is the HP back to Greenland for a reload. This I believe is what the 0Z ECM control run showed because I don't believe such low surface temps would be achieved with the upper temps of -5C.

[Bobby]

Latest NOGAPS still going for a very decent countrywide snow event as per Met Office (excl Scotland)

5-15cm widely looking at those precip charts.

Just seen the ensembles for the GFS, not exactly a convincing case for the breakdown, many are still cold through surface flow, some are actually cold are depth (through another easterly) the rest go for a similar 12z op solution...but even then probably half of those rebuild in the cold again...

So right now I'd say it really is 50-50, the Atlantic will try and force its way back in but as some of the older members should remember, once you've got these set-ups in place they can be very stubborn and easily able to come back.

I agree, what I would call what I think we'll see next week is a "partial snowy breakdown", at least initially. With altantic making attacks into us and delivering milder air but never really making much ground against the blocks, perhaps dumping lots of snow in the process. Then we could see the Atlantic finally winning through or the block restablishing itself and keeping it cold. Of course, the Altantic will win eventually - it always does.

[tinybill]

hi just looked at the gfs from the 10 to the 11 of jan if this happens they will have to call the army in!!

[mildmuck]

Latest NOGAPS still going for a very decent countrywide snow event as per Met Office (excl Scotland)

5-15cm widely looking at those precip charts.

I agree, what I would call what I think we'll see next week is a "partial snowy breakdown", at least initially. With altantic making attacks into us and delivering milder air but never really making much ground against the blocks, perhaps dumping lots of snow in the process. Then we could see the Atlantic finally winning through or the block restablishing itself and keeping it cold. Of course, the Altantic will win eventually - it always does.

I take it that's in the form of 'Showers' at the weekend rather than fronts and troughs ?

I haven't really viewed the fax charts yet.

[mcweather]

For what its worth my take on the tonights charts are that the ECM has it pretty much nailed. Experience has shown us all that in cold set ups like this it always pays to back the ECM against almost any GFS scenario. Interesting devlopments this weekend and again next week in the south. ( A touch of the 1947's there ).

I think what we need to bear in mind at the moment is that this is rapidly turning into an cold and snowy winter of perhaps historic proportions and as such some of the usual things that worry us don't really apply this time round. In our "normal winter scenarios, the Atlantic is usually still very strong and just gagging for a chance to rush back in. This is simply not the case this time round and one of the reasons why this could go on to be quite an historic winter.

Finally We are often told to back the form horse and the form horse so far this winter is Glacier point whose teleconnections analysis has been spot on in forecasting all that has happened so far. His current analysis suggests that the cold will win out come mid January and if its good enough for GP then its good enough for me.

Edited January 6, 2010 by mcweather

[West is Best]

And so it goes on ... what else is there to say? A week pretty much locked-in according to all the models with some penetratingly low temps and further snow possible. Anything beyond that is FI at the moment. These are the very synoptics of which so many of us dreamt, yet little hoped, let alone expected, would re-emerge. It really is like one of the great winters at the moment. It needs to continue in this vein through to mid-February for it truly to join the epics like '47 or '62/3 but I would say it is certainly now vying with '78/9. Extraordinary.

[Wayneywoo]

The shortwave holds the key this evening at 168hrs, if it verifies on the ecm then this will determine where the rest of January goes, the gefs ensembles show a clear split but the ecm operational run takes this under the block and prolongs the cold.

The gfs operational run decides to go the predictable route in it's lower resolution model output by ending the cold with the Atlantic winning, so which model do you believe this evening. To be honest anyone calling an end to the cold has to believe that the gfs is the one to follow in European blocking patterns, which is definitely not where i stand, the gefs ensembles actually have more colder solutions this evening and the gfs operational runs have been constantly criticized by forecasters in the USA, NOAA have generally followed the ecm and it's ensemble mean.

IMO the gfs will backtrack as it has basically done so for the last few weeks and will fall into line with the ecm/ukmo . So no end to the cold with more significant snow for eastern and se areas, also the chance for a Channel low.

Evening Nick,

When would NOAA make a statement as to what they think re. the models if they were to make one?

Thanks

[Devon-Nelly]

I'm backing the ECM on this one, as its done very well so far during this cold spell and not only that it points towards the teleconnections that GP pointed out for Mid-Jan, with the block moving back over Greenland and lows sliding underneath (and GP has been almost spot on so far)

Also it think its fair to say we've been locked into a strong cold blocking pattern which is going to take some bashing before it will move away. Personally i went for it turning milder in my Jan forecast the end of next week but the more i think about the more i think we could squeeze another week before milder air tries to push back in and even then i think its very likely that the cold air will return with avengence.

But in the short term Sunday looks like another snow fest for some areas, looking at the fax chart it has an occluded front straddling across the channel/southern England through the day, could be very intresting times indeed

Edited January 6, 2010 by Devon-Nelly

[Michael Fishermans Friend]

hi just looked at the gfs from the 10 to the 11 of jan if this happens they will have to call the army in!!

you have to the biggest ramper on here still gonna try to get to work on monday (as per your earlier post). Everychart you post is absolute snowaggedon, but no harm in a bit of fun.

[phil nw.]

Yes short term looks very cold as the N.Easterly flow strengthens .

It will fell bitter across the snowfields with with the probability of more snow for some as those troughs develop in the strong cold flow.

http://www.meteociel...h=72&carte=1007

Sunday too looks to be very wintry day.

http://charts.netwea.../h850t850eu.png

Out to T144hrs. and agreement that we keep a Scandi high and a more E/S.Easterly flow.

The uppers will be warmer as the cold air aloft has been mixwd out somewhat by the earlier low however the surface temps. still very cold.

http://www.wetterzen.../Rtavn14417.png

Beyond is uncertain and ideally we want the vortex to split to allow the block to retrogress towards Greenland for a solid continuation of the cold.

Edited January 6, 2010 by phil n.warks.

[kold weather]

And so it goes on ... what else is there to say? A week pretty much locked-in according to all the models with some penetratingly low temps and further snow possible. Anything beyond that is FI at the moment. These are the very synoptics of which so many of us dreamt, yet little hoped, let alone expected, would re-emerge. It really is like one of the great winters at the moment. It needs to continue in this vein through to mid-February for it truly to join the epics like '47 or '62/3 but I would say it is certainly now vying with '78/9. Extraordinary.

Yeah not many would have expected such a severe spell to be on the models at this stage back in late November...I think its fair to say even if broke down now the first half of winter will go down along side the likes of 81-82...

Anyway the truth is any breakdown is still past 168hrs at least even on the most progressive runs, pretty much the same place its been for the last few days.

The Atlantic will attempt to come in at some point of course but I've got my doubts it will be quite as easy as some of the models progs...as Nick very correctly says the shortwave at 168hrs really does hold the key, we will come close to a breakdown but I'm not has happened in all the severe winters at some point...

[casparjack]

The shortwave holds the key this evening at 168hrs, if it verifies on the ecm then this will determine where the rest of January goes, the gefs ensembles show a clear split but the ecm operational run takes this under the block and prolongs the cold.

The gfs operational run decides to go the predictable route in it's lower resolution model output by ending the cold with the Atlantic winning, so which model do you believe this evening. To be honest anyone calling an end to the cold has to believe that the gfs is the one to follow in European blocking patterns, which is definitely not where i stand, the gefs ensembles actually have more colder solutions this evening and the gfs operational runs have been constantly criticized by forecasters in the USA, NOAA have generally followed the ecm and it's ensemble mean.

IMO the gfs will backtrack as it has basically done so for the last few weeks and will fall into line with the ecm/ukmo . So no end to the cold with more significant snow for eastern and se areas, also the chance for a Channel low.

I have to say I agree with the scenario in broad terms. Not sure of the detail, but I just feel that we have already seen a clear demonstration of an entrenched pattern and the ECM have so far been largely close to the main theme, I go with them to have called it right...

Sub zero CET for January anyone?

[AtlanticFlamethrower]

I think I notice an ESE tilt to that T72 Fax chart... almost.

[nick sussex]

Evening Nick,

When would NOAA make a statement as to what they think re. the models if they were to make one?

Thanks

Hi well there seems to be quite alot of uncertainty upstream with shortwave energy and some divergence between the models, at the end of the day they have gone with the ecm for days 3 to 4 basically this coming weekend and then have weighted more of the ecm ensemble means upto day 7.

The gfs operational run is really quite close to the ecm in the higher resolution part of it's output but as soon as this hits the lower resolution part it quickly removes the block. IMO never trust the gfs when the most crucial part of the run crosses over from the higher to the lower resolution part of the output.

[sandstorm2]

The GFS is sticking to its guns with regard to bringing in milde weather in about 10 days, problem is it has been showing this 10 days hence for the last 3 so really it is contradicting itself, if you see what I mean.

SS2

[NorthNorfolkWeather]

Sub zero CET for January anyone?

If it (CET Average) is still below -1.1C on the 21st, it may happen. Now we need someone like Mr Data to tell us when the last sub zero month was.

As for the models, we have an interesting weekend in store in the Eastern counties, that wind will be bitter, as for the North, I'd like to see how low we go in Scotland as the clouds clear away -23C anyone?

EDIT:

Jay Wynne on BBC just saying no respite for 10-15 days, so 16th -21st before a break? He's been reading GP's and BFTP's analysis

Edited January 6, 2010 by NorthNorfolkWeather

[weather eater]

And so it goes on ... what else is there to say? A week pretty much locked-in according to all the models with some penetratingly low temps and further snow possible. Anything beyond that is FI at the moment. These are the very synoptics of which so many of us dreamt, yet little hoped, let alone expected, would re-emerge. It really is like one of the great winters at the moment. It needs to continue in this vein through to mid-February for it truly to join the epics like '47 or '62/3 but I would say it is certainly now vying with '78/9. Extraordinary.

Models wise I have a lot of time for the ECM not just because it shows what I want to see but because it has support from the teleconnection data and the GFS has been playing catch up with it all week.

As for 78/79, it rather depends from what perspective you’re coming from. In terms of snow there been nothing like it so far this year, that's not to say we haven't had some great falls because we have, but the snow I witnessed that year was pretty phenomenal. Blizzards keep being talked about on the news, but that year we had true blizzards the drifts were over my head, it was not a case of doing a bit of gritting and few hours later the main roads are back open, which was the case here yesterday.

[mcweather]

If it (CET Average) is still below -1.1C on the 21st, it may happen. Now we need someone like Mr Data to tell us when the last sub zero month was.

As for the models, we have an interesting weekend in store in the Eastern counties, that wind will be bitter, as for the North, I'd like to see how low we go in Scotland as the clouds clear away -23C anyone?

Last sub zero month was feb 1986