Winter Model Discussion - 11/01/13 00z Onwards

[TEITS]

Just as GFS really jumps on board, the ECM jumps off t144. Here we go again

BFTP

I don't think thats a fair assessment. The main issue with the models has been with regards to Mondays LP system and thankfully the GFS has come on board. The ECM beyond +144 is one of many options. Personally I suspect the HP will be further N and we shall continue to see the undercutting output.

[steelermark]

ECM EPS quite poor with lots of perturbations showing the collapse of the high over the UK or westerlies. Also % going for easterly.

I really must question the reliability of the ECM and its EPS of late.

Although GFS has been getting slack, it is the leader at present IMO.

6z will be very interesting.

It was only yesterday when the GFS did a complete U turn on it's output whilst the ECM maintained it's theme.

I'm sure some don't read the verification stats that are posted on a regular basis. UKMO @ no.1, ECM @ No.2 then GFS @ no.3. How is that being the leader at present??

Edited January 11, 2013 by steelermark

[chris55]

At the moment Wales/SW England/Ireland could miss out on snowfall during Monday with rain instead. However like I said this morning how far W the snowline will be on Monday remains very uncertain. However what looks likely is as this LP sinks S the colder upper temps will begin to back W during Tues.

ECM 850s Mean for Mon/Tues, with cold air at the surface I'd expect snow for many inland, maybe excluding south west Wales and Devon Cornwall.

[chris55]

We can't really say any model is "leading the way" at the moment, runs past day 3/4 are changing all the time, along with there respective ensembles. We will just have to accept that in this current period of model watching changes are inevitable and until we see a consistent across the board agreement that will remain.

[Methuselah]

What we must all bear-in-mind is that whatever any individual model-runs may be saying, at T+144 and on, is highly unlikely to approach reality; and, even if they do, it's likely to have been via an erroneous route.

Being able to predict (guess?) how any particular run will develop is not the same as forecasting actual weather?

[nick sussex]

Looking at the ECM postage stamps a change from yesterday evenings with more mobile solutions on offer.

This maybe a response to the PV dropping into eastern Canada, this is likely to ignite the jet so its important that you get a decent ridge to the north or ne to make sure any energy heads to the south of the UK:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

[EML Network]

Yes, the GFS Ensembles from the 18z run yesterday were looking very much like they wanted to bring Low Pressure from the West and run it SE through the UK, slipping just over the SW and into N France (In essence something of a channel Low) , and whilst this morning running through the ensembles...this still looks like a possibility some time around Thursday next week, it's not got quite as much support as if had on the 18z as a possible scenario.

However, the ECM and JMA are not a million miles away from this solution at all, and IMO there may possibly be a series of Low's coming in off the Atlantic and sliding underneath the UK, clipping the South West...as long as High Pressure can maintain itself over the Norwegian Sea are.

The ECM has been playing around with this type of set up for a few days and the overnight run still has this solution for the initial Low Pressure system moving down from Iceland and taking an almost direct South movement, before slipping into Southern Europe...so the ECM gives us a decent Easterly on Thursday next week.

However, I've yet to see the GFS Control run play around with this idea, it seems intent on keeping that initial Low Pressure over the Norwegian Sea, the Operational 00z run, does follow what many of the 18z Enselbles were showing last night, all be it with the Icelandic Low being integrated into the secondary Low that's spat out from the tip of S.Greenland, this then undercutting the high to give us a brief Easterly, whilst yet another Low follows in it's wake to give yet another brief Easterly.

So we've seen several ECM runs of late and now various GFS Ensembles runs and the overnight Op, play around with the idea of Low's moving in from the North West and undercutting the UK.

With cold air already well established before this happens, I am beginning to get very excited about next weeks prospects , not to mention the weekends slim chances of transitional snow fall.

Things are looking increasingly promising

[Frosty.]

There are far too many uncertainties within the next T+120 hours for anyone to worry about where the Ecm 00z op run is taking us, it just shows that despite SSW, the models can still easily show bog standard winter average/mild zonal charts. I'm now hoping the gfs is on the right track after it's poor recent few days.

[BLAST FROM THE PAST]

I don't think thats a fair assessment. The main issue with the models has been with regards to Mondays LP system and thankfully the GFS has come on board. The ECM beyond +144 is one of many options. Personally I suspect the HP will be further N and we shall continue to see the undercutting output.

Dave

Justs look at 12z and 00z and even think of 00z yesterday, that is a huge switch by the ECM post 144, so I think its very fair, its plain awful medium term pure and simple. I'm not too bothered as the models are just not to be relied on and any solution is possible at present model wise.

BFTP

[Severe Siberian icy blast]

I don't think thats a fair assessment. The main issue with the models has been with regards to Mondays LP system and thankfully the GFS has come on board. The ECM beyond +144 is one of many options. Personally I suspect the HP will be further N and we shall continue to see the undercutting output.

Just a quickie , have a read on chio's post in the strat thred just now , I agree entirely with it , it seems as if the ECM is barking up the wrong tree this morning, out of sync with all other signals.

[BLAST FROM THE PAST]

ECM 850s Mean for Mon/Tues, with cold air at the surface I'd expect snow for many inland, maybe excluding south west Wales and Devon Cornwall.

There is quite a lot of elevation in those regions, I don't think they will totally miss out

BFTP

[jimben]

I am not to worried by the ECM forecast "warming" towards the end of next week, plenty of snowfall opportunities before then which in themselves may change the forecasts. More importantly, some learned members have already indicated that there will be a slight warming before the weather once more plunges into the cold created in part by the sudden stratospheric warming. Happy and interesting days ahead.

[BLAST FROM THE PAST]

Snow chances on weekend have been well sent south, as Steve M says, south of M4 and moving further south

BFTP

[smhouston]

ECM EPS quite poor with lots of perturbations showing the collapse of the high over the UK or westerlies. Also % going for easterly.

I really must question the reliability of the ECM and its EPS of late.

Although GFS has been getting slack, it is the leader at present IMO.

6z will be very interesting.

Don't know how you can say that TBH. The GFS for my region was saying T850s of 5+ for Monday only 1 to 2 days ago, now it's finally made it's mind up and gone for around -5, a massive difference, something which all the other models had been showing. Very poor from the GFS at such a short timescale. As IB said at the time, it's either going to be cold or mild, and it's definitely showing cold. I hope some people have learnt not to just jump on to 1 model, and wait until the ensembles have a lot less scatter than they had rather than winding people up with flippant statements. It was always likely that all the models would meet in the middle

Anyway, very nice to wake up and see the GFS go for cold. As for the ECM mildness starting to show, didn't GP or BFTP say he was expecting a brief period of mild to come between the 16 and 21st before the "proper" cold comes in from the effect of the SSW?

[beefy201]

Morning all! And in particular my St. Stephens friend👴 it's all getting very exciting isn't it ðŸ™

[lord stratus]

There is quite a lot of elevation in those regions, I don't think they will totally miss out

BFTP

I believe Monday will turn out to be a mainly western event, northwest England, Wales and southwest will be the favoured areas

[Troubleatmill]

Looking at the ECM postage stamps a change from yesterday evenings with more mobile solutions on offer.

This maybe a response to the PV dropping into eastern Canada, this is likely to ignite the jet so its important that you get a decent ridge to the north or ne to make sure any energy heads to the south of the UK:

http://www.ecmwf.int...t!2009112700!!/

Yes Nick, we really need to see a decent HLB develop for the cold to continue, the atlantic is a conveyor belt and without decent HLB a more mobile set up will be the end product, we are ok at the moment with reletively weak low pressure out in the antlantic, but as soon as it fires up again, as it will it, we need something to divert them south, what we have at the moment would not be enough, but thankfully plenty of time for something to happen,

Edited January 11, 2013 by Nick JB

[No Balls Like Snow Balls]

-5c uppers now moving into Eastern UK so the cold transition is well under way.

Models looking good for a decent countrywide snowfall event Mon night into Tues.

Lot's to look forward to over the next couple of days.

Anything after mid-week currently showing in the models is probably not worth the paper it is written on at the moment given current model volatility - but having said that i think the odds are just in favour of staying cold with subsequent snow risk.

[beefy201]

I did say on Wednesday that Saturday's snow would be south of m4, and even mr Fergie dissed me lol. Good news for some is I think Monday's snow line will be east of Wales and the south west of England which should mean all of england should see some snow before midnight Monday 😱

[Liam J]

It seems the 00z ECM op has no support for the high pressure build on the ensembles, a few tweets from Matt Hugo this morning, ECM32 sounds promising but I'm not sure how much faith can be placed in long term outputs given the problems the short - medium term modelling is having at getting a good handle on developments.

Matthew Hugo â€@MattHugo81

No support for the high pressure from the EC ensembles, but the ensemble mean brings in a milder/unsettled W'ly now by Sat 19th Jan.

Matthew Hugo â€@MattHugo81

Latest EC32 continues previous trend with pressure always higher to the N or NW of the UK throughout with temps 2C or 3C below avg into Feb.

Edited January 11, 2013 by Liam J

[EML Network]

Looking at the ECM, In my opinion this is what goes "Wrong" so to speak.

The Low Pressure system as highlighted below at +120 slips well south into Spain (see other image at the bottom at + 144), it's this that then allows the High to drop into the Gap the Low Pressure system leaves as it's integrated into that large system over Italy , the High then moves toward it's default Azores position, with milder South Westerly's looking primed to run over the top.

If the Low pressure as highlited below were to take a more northerly route or even deepen then it's a game changer to a more prolonged cold spell of weather and probably a snowier one too

[Matty M]

I feel people have perhaps overlooked that the ECM moved towards the GFS solution as much as vica-versa.

GFS was first to indicate the power of the Atlantic incursion, even if it goes under the block as we hope.

If i could choose one model to follow i would pick the GFS and that's being just IMO.

GFS is looking good though as this point and it's solution would be the most exciting and rewarding for many particularly in England.

[phil nw.]

Nothing to be down about this morning if you are a cold lover.

The main trend by all of the models is colder air coming from the east with chances of some snow over the weekend in eastern areas in the form of showers and then from the north west spreading south on Monday from a shortwave development.

As the system goes through we see a renewal of the cold from the east

maintaining the wintry feel.

After this point as ever some differences are apparent between the models with the amount of blocking showing to our north west but i think at the moment it`s best to view developments iin 4-5 day blocks as the pattern is continually changing.

At the very least it looks to be quite cold now well into next week.

[warrenb]

Got to say GEM for me, it has been going with this for a while now and I believe it has more stratospheric modelling than the other models. When that flips to mild I will know the end of the cold spell is coming. Stop slavishly following 1 run at a time, the ECM blipped the other day and then came back.

[Liam J]

Got to say GEM for me, it has been going with this for a while now and I believe it has more stratospheric modelling than the other models. When that flips to mild I will know the end of the cold spell is coming. Stop slavishly following 1 run at a time, the ECM blipped the other day and then came back.

The 00z GEM has flipped to a more milder outlook certainly when compared to all the previous excellent runs, it is however only one run though so best leave that one aside for the time being given the very volatile situation.

http://www.meteociel.fr/modeles/geme_cartes.php