Model Output Discussion - 8th December Onwards

[Polar Maritime]

Compared to what the models were showing yesterday, that's an upgrade in itself since it showed milder everywhere by thursday, if we have further upgrades the cold block may win. I currently don't see that there can be high confidence in any solution beyond midweek!

Yes Frosty, even the METO have high uncertainty beyond next friday.

[The PIT]

Interesting drift by the GFS in FI land. However model number one the ECM it says no or has ECM now become unreliable since it ain't showing icebergs and polar bears outside our doors??

The country file forecast is hedging it's bets for the end of week although they favour a return to mild weather as the more likely outcome.

Edited December 9, 2012 by The PIT

[snow1975]

Interesting drift by the GFS in FI land. However model number one the ECM it says no or has ECM now become unreliable since it ain't showing icebergs and polar bears outside our doors??

The country file forecast is hedging it's bets for the end of week although they favour a return to mild weather as the more likely outcome.

I don't think the ECM is as good as some people make it out to be. JUst remember the extreme easterly a few days back to suddenly backtrack to the Atlantic. I think the GFS is underestimated by many, including the MetO.

[Frosty.]

Indeed, I said last night, I think the UK could be right in the middle of a mega battleground between the cold to our East and the Atlantic to our west. I don't see any prolonged mild periods in the short to mid term. A mix of cold and cool n wet is most likely.

It's the angle of the breakdown that is most interesting to me, yesterday it was west to east meaning the mild could sweep in much faster but today it looks more like a sw/ne attack which allows cold SEly winds ahead of it and with even more undercut the mild advance could be stopped and even forced south again, it's more on a knife edge today whereas yesterday it looked a foregone conclusion, we will now find out how strong this cold block is going to be. A very interesting week ahead.

[Methuselah]

I do think saying they are reactive rather than proactive is abit unfair, but i think if we looked in an unbiased way the models have shown the outlook, remembering they give more credability to EC than GFS in fi, that we would if pushed have to give a similar outlook. Its what is shown as most likely on the previous runs by EC. However a few runs by the EC and others in Fi trending cold, also with a different senior forecaster on the day (maybe) that a different outlook may be given. They can not have a biased in any weather to make what is often at best a far from accurate medium range forecast. Its what the forecaster would have seen in the EC previous runs and its what its hinted to us too, however i am hopeful that changes are a foot and that will reflect later in the week on their forecasts, if not the sledge will need to be put back up in the actic until 2013, i don't want to go back to the actic !!!

How can the MetO be 'proactive', pyrotech? Nothing they can do or say can ever have any influence on the weather, on way or the other...I guess that they could pre-empt data, but what would that achieve?

[Severe Siberian icy blast]

It's the angle of the breakdown that is most interesting to me, yesterday it was west to east meaning the mild could sweep in much faster but today it looks more like a sw/ne attack which allows cold SEly winds ahead of it and with even more undercut the mild advance could be stopped and even forced south again, it's more on a knife edge today whereas yesterday it looked a foregone conclusion, we will now find out how strong this cold block is going to be. A very interesting week ahead.

My thoughts exactly to be honest , and past experience tells me things don't go so clear cut.

[Summer Sun]

Sorry off topic but any link to countryfile forecast.

Yes

[IDO]

It's the angle of the breakdown that is most interesting to me, yesterday it was west to east meaning the mild could sweep in much faster but today it looks more like a sw/ne attack which allows cold SEly winds ahead of it and with even more undercut the mild advance could be stopped and even forced south again, it's more on a knife edge today whereas yesterday it looked a foregone conclusion, we will now find out how strong this cold block is going to be. A very interesting week ahead.

I think that angle of attack is the only variable at the moment. It will dictate the pace of the breakdown and whether there is frontal snow. GEFS, ECM and now UKMO (though with caveats) all have on their recent runs going with a quick breakdown with a mild airflow proceeding the rain giving probably only snow to high ground. Of course the warm fronts may be slowed by the block and this may help wash out the warmer uppers so a few hours of snow may be possible.

However by next weekend the milder air will win. The t240 is as far as I will go out, and the GEFS mean suggests the Russian High is keeping the cold to our east:

http://modeles.meteo...-21-0-240.png?6

http://modeles.meteo...-21-1-240.png?6

Again the mean has an Icelandic low from T240 till the end of the run:

http://modeles.meteo...-21-1-240.png?6

http://modeles.meteo...-21-1-384.png?6

That suggests a zonal rut on the current model run. A zonal setup is comparatively very easy to forecast, and that I suspect is why the UKMO has high confidence up till Christmas. That pattern is very difficult to breakdown and as others have suggested there may be a constant feed of energy from the vortex shifting places fuelling this setup. Hope not but that is the obvious call.

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

[karyo]

I just woke up after a night out and what a nice surprise! The cold spell has been extended and we also have a good possibility for breakdown snow. I am happy with that for now.

I think the Atlantic will win at least for a time but with the block to the east not moving far, we can hope for further attacks from the east.

Karyo

[pyrotech]

How can the MetO be 'proactive', pyrotech? Nothing they can do or say can ever have any influence on the weather, on way or the other...I guess that they could pre-empt data, but what would that achieve?

Reactive as in they react to what models predict - yes

Proactive in reading different models and predicting an out come in the future, using various data and choosing most likely outcome.

Proactive by issuing timely, accurate and informative warnings, at different stages before a situation arrives.

Reactive would be telling us what the weather is now and yesterday, for issuing warnings that are out of date , as in for yesterday.

I would expect such a regular user as yourself to see just how volatile the models are, its okay for us to jump on a model run and talk about its outcome, something else to give that outcome to public, emergency services and industrial sectors, where a inaccurate forecast can be hugely costly.

The models later this coming week are very volatile, slight changes over 5 days could see quite dramatic changes in the outcome, lets not even go beyond that. A forecaster can not rely on a single or couple of runs, they would have to look at the big picture which means the last run trend, accross model too. I hope the new trend continues and that meto proactively adjust their forecast to reflect it.

This is probably the most volatile and exciting model runs that we have seen for 12 months.

[Gavin Hannah]

Check out those fronts building up in the countryfile forecast. 3 in a row!

It's the angle of the breakdown that is most interesting to me, yesterday it was west to east meaning the mild could sweep in much faster but today it looks more like a sw/ne attack which allows cold SEly winds ahead of it and with even more undercut the mild advance could be stopped and even forced south again, it's more on a knife edge today whereas yesterday it looked a foregone conclusion, we will now find out how strong this cold block is going to be. A very interesting week ahead.

Hopefully a 18z or 06z type breakdown. Providing us with an undercutting low.

Edited December 9, 2012 by IBringTheHammer

[stainesbloke]

It's the angle of the breakdown that is most interesting to me, yesterday it was west to east meaning the mild could sweep in much faster but today it looks more like a sw/ne attack which allows cold SEly winds ahead of it and with even more undercut the mild advance could be stopped and even forced south again, it's more on a knife edge today whereas yesterday it looked a foregone conclusion, we will now find out how strong this cold block is going to be. A very interesting week ahead.

Yes, each run seems to favour the cold block that little bit more. Still 5 days away so the details will change but it doesn't look like a clean sweep by the Atlantic by any means. Great time to be model watching! Even if we don't see exactly what we want.

[Gavin Hannah]

If it sets up just right, the cold could come sweeping in from the continent, just along the west side of the UK, and stall. That would be a result.

[Welsh_Weather]

I think that angle of attack is the only variable at the moment. It will dictate the pace of the breakdown and whether there is frontal snow. GEFS, ECM and now UKMO (though with caveats) all have on their recent runs going with a quick breakdown with a mild airflow proceeding the rain giving probably only snow to high ground. Of course the warm fronts may be slowed by the block and this may help wash out the warmer uppers so a few hours of snow may be possible.

However by next weekend the milder air will win. The t240 is as far as I will go out, and the GEFS mean suggests the Russian High is keeping the cold to our east:

Again the mean has an Icelandic low from T240 till the end of the run:

That suggests a zonal rut on the current model run. A zonal setup is comparatively very easy to forecast, and that I suspect is why the UKMO has high confidence up till Christmas. That pattern is very difficult to breakdown and as others have suggested there may be a constant feed of energy from the vortex shifting places fuelling this setup. Hope not but that is the obvious call.

How can you even say this is the obvious outcome? The models are struggling with what is going to happen after Wednesday and Thursday and you are talking about obvious outcomes after T240. Ok this is your opinion but it is far from obvious that we are going to be stuck in a "zonal rut".

Also nowhere in the UKMO forecast does it mention high confidence.

Edited December 9, 2012 by Welsh_Weather

[Methuselah]

Reactive as in they react to what models predict - yes

Proactive in reading different models and predicting an out come in the future, using various data and choosing most likely outcome.

Proactive by issuing timely, accurate and informative warnings, at different stages before a situation arrives.

Reactive would be telling us what the weather is now and yesterday, for issuing warnings that are out of date , as in for yesterday.

I would expect such a regular user as yourself to see just how volatile the models are, its okay for us to jump on a model run and talk about its outcome, something else to give that outcome to public, emergency services and industrial sectors, where a inaccurate forecast can be hugely costly.

The models later this coming week are very volatile, slight changes over 5 days could see quite dramatic changes in the outcome, lets not even go beyond that. A forecaster can not rely on a single or couple of runs, they would have to look at the big picture which means the last run trend, accross model too. I hope the new trend continues and that meto proactively adjust their forecast to reflect it.

This is probably the most volatile and exciting model runs that we have seen for 12 months.

Thanks for the reply, pyro. Appreciate it!

[Severe Siberian icy blast]

I think that angle of attack is the only variable at the moment. It will dictate the pace of the breakdown and whether there is frontal snow. GEFS, ECM and now UKMO (though with caveats) all have on their recent runs going with a quick breakdown with a mild airflow proceeding the rain giving probably only snow to high ground. Of course the warm fronts may be slowed by the block and this may help wash out the warmer uppers so a few hours of snow may be possible.

However by next weekend the milder air will win. The t240 is as far as I will go out, and the GFES mean suggests the Russian High is keeping the cold to our east:

Again the mean has an Icelandic low from T240 till the end of the run:

That suggests a zonal rut on the current model run. A zonal setup is comparatively very easy to forecast, and that I suspect is why the UKMO has high confidence up till Christmas. That pattern is very difficult to breakdown and as others have suggested there may be a constant feed of energy from the vortex shifting places fuelling this setup. Hope not but that is the obvious call.

To be honest that's so misleading, you are using the charts to manipulate your forecast.

You know the models have took a big swing today in favour of more sliding activity rather than a zonal bulldozer , if it was trends we look for then that trend is the block is stronger, the jet Is further south , the block holds a lot more resistance and indeed in the ukmo shows signs of retrogression to Greenland, to say by next wkend the cold air "will win" in my mind is naive ,once you have a slider in place the fronts normally follow , which in turn strengthens the block and has a big knock on affect to our weather.

To say the movement of the vortex is helping to fuel this setup is very wrong and misleading. The reason why the models have been showing this zonal mess is because they don't no where to place the vortex and will always regroup it in its default pattern if the models don't no what to do . Now the models have finally began to come to terms with the repositioning of the vortex we should see more stable runs, and I highly expect the emphasis will be on blocking retrogressing to Greenland , rather than zonal mess.

Then to say the rut will be very hard to break is also misleading , you obviously take each run as gospel and don't look at the bigger picture, because if you did , you would realise that what the models have been showing as trends is massive northern blocking and a destroyed vortex, which although doesn't guarantee cold for the uk, it' makes it more likely.

And finally the uk outlook . That update that every day, if you had looked 4 days ago it was saying how cold the next 2 wks will be, they go with what the charts show , aswell as other variables obviously but the outlook changes from day to day , sometimes they don't change much, other times they change everything about it.

It was only a few days ago that Ian fergi told us the met are concerned about next tue , as there ukv model showed 10cm of snow moving over England, only to completely change on the next run, so to be honest there forecasts change with the models, so if the models change , then so will there forecasts.

Edited December 9, 2012 by Severe Siberian icy blast

[The Melting Snowman in Guernsey]

Gfs FI looks great again but that's all it is, not gospel. Seeing as the new week has become a total let down for cold lovers, me included, I won't be looking at any charts until this time next week as at the moment everything is firmly up in the air and in-forecastable. Have safely put the 3 sledges back in the loft for the next 10 days !!!

TMSIG

Edited December 9, 2012 by shuggee

[stainesbloke]

If it sets up just right, the cold could come sweeping in from the continent, just along the west side of the UK, and stall. That would be a result.

Big result! Not massively likely just yet but with 5 days to go til the breakdown, who knows? These types of model scenarios were a lot more common back in the late 70s and through the 80s, when we ended up with a lot of snowfall on many occasions. I'm keeping expectations low to avoid getting carried away lol.

[karyo]

Big result! Not massively likely just yet but with 5 days to go til the breakdown, who knows? These types of model scenarios were a lot more common back in the late 70s and through the 80s, when we ended up with a lot of snowfall on many occasions. I'm keeping expectations low to avoid getting carried away lol.

Always a good idea!

[BLAST FROM THE PAST]

IMO all the models have shown overnight is that we are in the battleground zone and that hasn't changed, sometimes right over us, sometimes just to our west or sometimes to our east. What I don't think the models will do is completely backtrack to show us in a prolonged northern blocking controlled freeze. That I'm of the opinion has gone for now and won't materialise and the week ahead may be Decembers coldest period. So am going to enjoy this week and the tweaks here and there, then get ready for a potential very wet, cyclonic dominated period. I think a lot of forecasters on here have deep down accepted that this one will be a close miss to a stormer. Its early days though and a good start to winter.

BFTP

[Gavin Hannah]

Looking forward to see what the 12Z throws our way. I think the 00Z and 12Z are similar in the output atm, while the 06Z and 18Z are together in their ideas. One set of runs will eventually give way to the other.

Off , But, watching Ice Age atm.... hoping the UK can get in on epic wintry stuff this year.

Edited December 9, 2012 by IBringTheHammer

[IDO]

How can you even say this is the obvious outcome? The models are struggling with what is going to happen after Wednesday and Thursday and you are talking about obvious outcomes after T240. Ok this is your opinion but it is far from obvious that we are going to be stuck in a "zonal rut".

Also nowhere in the UKMO forecast does it mention high confidence.

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.

[Gavin Hannah]

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

[Severe Siberian icy blast]

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

Agree entirely . The uk met change like the clappers, so does Ian's quotes, and so does the ukv model , no disrespect there from me , I'm just stating the facts.

[fromey]

Posted by Ian Ferguson in the S/W Thread

Posted Today, 12:41

PS That last UKMO analysis obviously based on 00z output of course. Next material prepared by them at midnight based on 12z. It's the deputy chief forecaster who writes them up. Next 4-5d detailed analysis due around 10pm

.

Edited December 9, 2012 by fromey