General Model Output Discussion

[Methuselah]

Here's a new thread...And PLEASE stick the topic!

[PB22]

Heh, that cut off low at T+216 on ECM goes east into the continent, and could bring snow to southern areas:

No real sign of any breakdown from ECM tonight.

[PB22]

JMA doesn't show any breakdown either:

http://www.wzkarten.de/pics/Rjma961.html

http://www.wzkarten.de/pics/Rjma1201.html

http://www.wzkarten.de/pics/Rjma1441.html

http://www.wzkarten.de/pics/Rjma1681.html

http://www.wzkarten.de/pics/Rjma1921.html

[Frosty.]

The ECM 12z is an upgrade on the 00z, the cut off ridge idea has been binned for now at least and the link up to the scandi high is an improvement with an E'ly breeze for all areas, T+216 looks very snowy but by T+240 i'm just wondering if the atlantic is going to battle it's way in or whether the cold will win out, it looks 50/50 to me whether our v.cold spell will extend beyond mid month but a very wintry week ahead. We need more of a northern perspective on here because reading through the posts it seems like just a southern event or maybe our scottish friends are fed up with the cold & snow already!

[weather eater]

Yes the ECM is another cold run, but it could be better for a wider area of the country at least for snow potential, To be honest its not worth getting bothered by, as I’m sure we will see a good few changes yet in terms of the detail. Still the high doesn’t want to get much further south otherwise it wont be discussions about wide spread snowfall, it will be will be a case of wide spread moaning. As my wife wisely says, 5 days is a long time in weather land, I've got very wary of making the mistake of giving her predictions for weather at that range.

[Serendipity]

OK I don't post in this topic area often as people are far more knowledgable than me and I don't want to make a twit of myself but I'm slightly bewildered by people feeling that snow in the next week or so will be confined to the SE only? True it seems to me that the chances of significant and very disruptive snowfall are really confined to that corner but looking at the fax charts I would suggest we could get snow through the midlands and other areas on Tuesday into wednesday - I don't know how to post the link but the 60 hr fax shows a trough unless I am reading it wrong that could bring snow into the north midlands and northern wales also.

Then the GFS 12z showed more potential for the central southern area and the sw midlands and sw wales area on Tuesday and then again later in the week, Thursday and then the weekend which is really too far out offers more possibilities surely?

Snow isn't confined just to the east coasts either as showers seem to potentially make their way a fair bit inland on other days.

I'm quietly optimistic that areas such as the midlands will see snow in the upcoming days. We may not get the amazing amounts that the SE look likely to get but who can blame them for being excited? But we do have prospects...

Be gentle with me!

[Thundery wintry showers]

I think you're right- with a sustained flow and a significant easterly component developing to the wind, this is no 36 hour northerly with wintry showers hugging the east coast, and at times some of the showers should make it a fair way inland. Some people have perhaps been looking too literally at precipitation outputs from the main models, but the models have a tendency to oversimplify the distribution of convective activity that moves in from the North Sea, and also underestimate its extent.

Unlike in the SE, snow showers will probably be "hit and miss" affairs in the Midlands but at least some parts of the Midlands should have a fairly significant snow cover by the end of the week.

[PB22]

OK I don't post in this topic area often as people are far more knowledgable than me and I don't want to make a twit of myself but I'm slightly bewildered by people feeling that snow in the next week or so will be confined to the SE only? True it seems to me that the chances of significant and very disruptive snowfall are really confined to that corner but looking at the fax charts I would suggest we could get snow through the midlands and other areas on Tuesday into wednesday - I don't know how to post the link but the 60 hr fax shows a trough unless I am reading it wrong that could bring snow into the north midlands and northern wales also.

Then the GFS 12z showed more potential for the central southern area and the sw midlands and sw wales area on Tuesday and then again later in the week, Thursday and then the weekend which is really too far out offers more possibilities surely?

Snow isn't confined just to the east coasts either as showers seem to potentially make their way a fair bit inland on other days.

I'm quietly optimistic that areas such as the midlands will see snow in the upcoming days. We may not get the amazing amounts that the SE look likely to get but who can blame them for being excited? But we do have prospects...

Be gentle with me!

Superb post!!

No-one knows for sure what will crop up and when, but there is the potential for just about everyone to see some snow at least over the coming days! These are charts that many have dreamed off and for them to be coming up at this time of year is just perfect.

[kold weather]

The ECM 12z is an upgrade on the 00z, the cut off ridge idea has been binned for now at least and the link up to the scandi high is an improvement with an E'ly breeze for all areas, T+216 looks very snowy but by T+240 i'm just wondering if the atlantic is going to battle it's way in or whether the cold will win out, it looks 50/50 to me whether our v.cold spell will extend beyond mid month but a very wintry week ahead. We need more of a northern perspective on here because reading through the posts it seems like just a southern event or maybe our scottish friends are fed up with the cold & snow already!

Very much 50-50, I keep looking at the charts between 216-240hrs at both the heights and the pressure and I'm really not sure how it'd evolve...there are aspects that would hint at a return of the Atlantic BUT the PV over the north Atlantic starts to beocme absorbed by a PV further NW...if that happens then that low will weaken and shift back NW which would favour a return to the cold...but its tight either way!

Ah well there is so much to watch before then its not worth worrying too much over it for now...

[weather eater]

OK I don't post in this topic area often as people are far more knowledgable than me and I don't want to make a twit of myself but I'm slightly bewildered by people feeling that snow in the next week or so will be confined to the SE only? True it seems to me that the chances of significant and very disruptive snowfall are really confined to that corner but looking at the fax charts I would suggest we could get snow through the midlands and other areas on Tuesday into wednesday - I don't know how to post the link but the 60 hr fax shows a trough unless I am reading it wrong that could bring snow into the north midlands and northern wales also.

Then the GFS 12z showed more potential for the central southern area and the sw midlands and sw wales area on Tuesday and then again later in the week, Thursday and then the weekend which is really too far out offers more possibilities surely?

Snow isn't confined just to the east coasts either as showers seem to potentially make their way a fair bit inland on other days.

I'm quietly optimistic that areas such as the midlands will see snow in the upcoming days. We may not get the amazing amounts that the SE look likely to get but who can blame them for being excited? But we do have prospects...

Be gentle with me!

Yes this is a funny old place, I think everybody is pretty switched on to events mid week, however I think there are some understandably envious eyes being cast at the SE during Friday\Saturday. Many looking for the models to upgrade so as to take in a larger portion of the country, there's some potentially massive falls in the SE and everybody wants to see a bit more of that action. It’s very rarely that I wish that I still lived in my native EA, but this is one occasion. I rather hope that this is one occasion that the ECM backs off in favour of the GFS.

[nick sussex]

Another set of excellent model outputs this evening, still some differences regarding the strength of the easterly though which is to be expected at this timeframe.

I did notice from the previous model thread some of the negative posts regarding the ecm which made me laugh! oh people do have short memories regarding recent winters in the UK. Nearly every sustained cold spell revolves around easterly to northerly and then back to easterly, the synoptics that sustain cold give those areas always the highest risk of the most snow, it's just a fact of life living in the UK.

However sustained cold does give other areas a better chance of seeing some snow. It really is impossible to please everyone regarding synoptics.

[Frosty.]

Very much 50-50, I keep looking at the charts between 216-240hrs at both the heights and the pressure and I'm really not sure how it'd evolve...there are aspects that would hint at a return of the Atlantic BUT the PV over the north Atlantic starts to beocme absorbed by a PV further NW...if that happens then that low will weaken and shift back NW which would favour a return to the cold...but its tight either way!

Ah well there is so much to watch before then its not worth worrying too much over it for now...

I'm not sure which model to trust beyond next thurs/fri because the gfs is so much different to the ecm in FI and actually better for a more prolonged cold spell although we would lose those very cold uppers but still cold enough at the surface to stop a proper thaw, a slow daytime thaw maybe but freezing up every night. Still, maybe we should just focus on the wintry mayhem that looks certain to occur between late mon-early thursday in the north and tuesday-saturday in the south and especially the southeast which looks like ending up being the most wintry area in the uk.

[Serendipity]

Another set of excellent model outputs this evening, still some differences regarding the strength of the easterly though which is to be expected at this timeframe.

I did notice from the previous model thread some of the negative posts regarding the ecm which made me laugh! oh people do have short memories regarding recent winters in the UK. Nearly every sustained cold spell revolves around easterly to northerly and then back to easterly, the synoptics that sustain cold give those areas always the highest risk of the most snow, it's just a fact of life living in the UK.

However sustained cold does give other areas a better chance of seeing some snow. It really is impossible to please everyone regarding synoptics.

I think the diffculty comes when the very well known posters start to get excited about the possible outcomes they see unfold. In previous winters we've struggled to "lock in" any significant cold spells and what has resulted is snow events that tend to creep up unexpectedly and then are over soon than you realise.

What we have this January, is a remarkably cold spell and unfortunately in all the general excitement, some people have found themselves assuming longterm cold = significant snowfall. I'm sure in the past, those in the know such as yourself, JH, Steve Murr, TEITS etc have always made it clear we need to get the cold in place and the snow events will follow.

It is hard when you see "ramping" from those in the know because for less experienced members it is easy to assume that the cold means everyone will see snowfall.

But we're definitely losing a sense of balance on this thread imo. I do understand the frustration from those AWAY from the SE and the excitement for those IN the SE but it would be good to see more comments from the experienced posters about what we need to be looking for in order for more people to benefit from this cold.

I for one think chances for the Midlands are currently being underplayed a little although I don't think we'll see large snowfall. As we get closer we're seeing slight shifts that could make all the difference and it's all to play for surely?

[LomondSnowstorm]

Is it such a sin if Western and Northern folk express their opinion that it remains rather dry for the forseeable?

For Ireland, Scotland and Wales it looks dry after Tuesday evening for the rest of the week

Far from ideal for us, FACT!

I know where you're coming from, but I'm far from convinced that eastern and southern Wales, eastern parts of Ireland and Eastern and Southern Scotland will avoid convective showers. Remember not to tak precipitation charts at face value, as convective snow streamers can set up under the noses of most models, which tend to underestimate convection showers at times. Yes the main area affected by this appears to be the southeast of England, but that doesn't mean that other areas won't see quite a lot of snow as well! Once the cold air is in place, snow events can come up from out of the blue - even events which give snow depths of around 6 inches might not be noted until maybe a day before it occurs.

LS

Edited January 3, 2010 by LomondSnowstorm

[Michael Winston]

I for one think chances for the Midlands are currently being underplayed a little although I don't think we'll see large snowfall. As we get closer we're seeing slight shifts that could make all the difference and it's all to play for surely?

Thanks for that post, Serendipity. I'm struggling to see why the front on Tuesday night into Wednesday will be marginal for the Midlands. There are clearly subtleties here that I'm blissfully unaware of. They're probably glaringly obvious too, but I'm noted for my lack of understanding!

Regards,

Mike.

Edited January 3, 2010 by Winston

[johnholmes]

OK I don't post in this topic area often as people are far more knowledgable than me and I don't want to make a twit of myself but I'm slightly bewildered by people feeling that snow in the next week or so will be confined to the SE only? True it seems to me that the chances of significant and very disruptive snowfall are really confined to that corner but looking at the fax charts I would suggest we could get snow through the midlands and other areas on Tuesday into wednesday - I don't know how to post the link but the 60 hr fax shows a trough unless I am reading it wrong that could bring snow into the north midlands and northern wales also.

Then the GFS 12z showed more potential for the central southern area and the sw midlands and sw wales area on Tuesday and then again later in the week, Thursday and then the weekend which is really too far out offers more possibilities surely?

Snow isn't confined just to the east coasts either as showers seem to potentially make their way a fair bit inland on other days.

I'm quietly optimistic that areas such as the midlands will see snow in the upcoming days. We may not get the amazing amounts that the SE look likely to get but who can blame them for being excited? But we do have prospects...

Be gentle with me!

I think you should read the Front Page story which is the forecast prepared by Nick F Senior Forecaster-he goes over all the ins and outs and whys and wheres for all the country.

[derrylynne]

Is it such a sin if Western and Northern folk express their opinion that it remains rather dry for the forseeable?

For Ireland, Scotland and Wales it looks dry after Tuesday evening for the rest of the week

Far from ideal for us, FACT!

I have seen these kind of synoptics before being an 'old un'. The low could in fact be a little further west, and that in what is a very small country width wise would make all the difference. In fact more than once have I seen forecasts of massive dumpings of snow for the SE - when in fact it were the SW that were being dug out the next day while the SE were mainly dry. In my opinion there is a lot of ramping to the extreme on this thread.

True places such as Kent, EA, and the NW will do well from snow showers or streamers - but to write off the chances of the rest of the UK at this time is wrong. A few days in weather is a long time, and there will be subtle changes that may well benifit other parts the UK at the expense of the SE...

[Serendipity]

Thanks for that post, Serendipity. I'm struggling to see why the front on Tuesday night into Wednesday will be marginal for the Midlands. There are clearly subtleties here that I'm blissfully unaware of. They're probably glaringly obvious too, but I'm noted for my lack of understanding!

Regards,

Mike.

Well others are more knowledgable than me but it seems to my untrained eye that we would have a fairly unstable airflow which could provide convective showers almost anywhere alongside the more organised systems? They wouldn't be shown on a regular chart so I think what we are seeing is the organised more certain systems and others could crop up, just as we saw in the SE a couple of weeks ago.

Bearing in mind that we are looking at very cold daytime temperatures, snow would lie and we could get a decent accumulative effect in some areas. It certainly seems to me that in the Midlands for example, we could get a couple of cms earlier in the week which is unlikely to thaw easily and could then be added to were we to get more showers.

And as to what happens later in the week, Thursday/Friday/ Saturday is still very much all to play for. The GFS already showed a slight shift to the NW which would bring snow to more areas and that could go in our favour more yet.

Of course it could all backfire too

Edited to add:

Thanks JH for replying to my post. I have read that (think I have read most of netweather!) but was meaning really that there seems to be a need to quantify WHY people are stating the latest ecm output or whatever is good - is it because it's good for your own area, or good due to sustained cold, or just good because of the potential for everyone? It just seems sometimes the national relevance gets lost but I'll shut up now

Edited January 3, 2010 by Serendipity

[benb]

I have seen these kind of synoptics before being an 'old un'. The low could in fact be a little further west, and that in what is a very small country width wise would make all the difference. In fact more than once have I seen forecasts of massive dumpings of snow for the SE - when in fact it were the SW that were being dug out the next day while the SE were mainly dry. In my opinion there is a lot of ramping to the extreme on this thread.

True places such as Kent, EA, and the NW will do well from snow showers or streamers - but to write off the chances of the rest of the UK at this time is wrong. A few days in weather is a long time, and there will be subtle changes that may well benifit other parts the UK at the expense of the SE...

I don't think anyone is writing anything off and based on the models of late I think the 'ramping' has been minimal.

It's been mostly a very informative thread for a couple of days now.

The focus of attention is always going to be on where the models are showing most of the action (ie heavy snow in the SE, in this case). However, the models are constantly evolving and developing. The snow risk is certainly going to shift to and fro throughout the week and this is part of the fun! Enjoy.

[PB22]

Short term details for the ECM run (precip, 850s) can be found here by the way: http://en.vedur.is/weather/forecasts/atlantic/#teg=temp&type=temp

[cyclonic happiness]

Short term details for the ECM run (precip, 850s) can be found here by the way: http://en.vedur.is/weather/forecasts/atlantic/#teg=temp&type=temp

Not a sausage for the midlands? Does this mean we are gonna see nothing or just that the ECM isn't good at precipitation charts or...is anyone good at precipitaion charts?

From the GFS it seemed like most areas will get at least some snow over the next few days but this chart is very depressing.

[Nick F]

OK I don't post in this topic area often as people are far more knowledgable than me and I don't want to make a twit of myself but I'm slightly bewildered by people feeling that snow in the next week or so will be confined to the SE only? True it seems to me that the chances of significant and very disruptive snowfall are really confined to that corner but looking at the fax charts I would suggest we could get snow through the midlands and other areas on Tuesday into wednesday - I don't know how to post the link but the 60 hr fax shows a trough unless I am reading it wrong that could bring snow into the north midlands and northern wales also.

Then the GFS 12z showed more potential for the central southern area and the sw midlands and sw wales area on Tuesday and then again later in the week, Thursday and then the weekend which is really too far out offers more possibilities surely?

Snow isn't confined just to the east coasts either as showers seem to potentially make their way a fair bit inland on other days.

I'm quietly optimistic that areas such as the midlands will see snow in the upcoming days. We may not get the amazing amounts that the SE look likely to get but who can blame them for being excited? But we do have prospects...

Be gentle with me!

Many areas of England and Wales, including the Midlands should see snow on Tuesday as the cold front moves through. You can see the cold front developing to the north of Scotland on tonight's 18z fax, shown by the triangles with dots in between, this will bring snow initially to Scotland tomorrow:

http://cache.netweather.tv/fax/PPVA89.png

Wednesday onwards, the northerly flow looks to veer more to the northeast across England, so east coastal areas will be most favoured for snow showers, however, I'm sure troughs in the flow will likely bring snow showers inland to the Midlands, and central southern England at times too, so good reason to be optimistic for this coming week certainly, even well inland from the N Sea coast. In the west, the wind looks to be more northerly, so Wales and SW England may benefit from snow showers developing down the Irish and Celtic Seas too. Does look like turning drier across Scotland away from coasts for the second half of the week, as pressure builds from the north.

Looking at this evening's model output, GEFS members and the ECM all point to the block drifting E from its current position over S Greenland and Iceland towards Scandinavia into the medium range, with winds tending to switch from the N to the NE than eventually the E by next weekend, with no let up in the cold in sight.

[Duane S.]

Great 12z output. Nearly there... Although I think the ECM does decrease the snow potential for some parts in the west it is still a great chart.

I really think the snow potential for central Southern coastal counties is starting to get really interesting. I keep saying it but we down here in the plughole of the UK really could have quite a dumping, not only maybe on Tuesday/Wednesday but also at the end of the week

I don't think in all my time here on NW, I have EVER ramped snow potential for me!

And yes I agree with you WIB, I really don't know what's wrong with some people. I think they could wake up to 50 foot snow drift blocking their doorway, yet still find something to complain about. Will all be melted in 2 months anyway, so what's the point etc etc etc.

I'm looking forward to (hopefully) being able to join in the nowcasting fun and put that stupid annoying lampost situated right outside my bedroom window to good use!

[Snowaddict]

Looking at all of the output this evening January Snowstorm, Eastern & Southeastern Ireland could potentially do very well next week, with rather heavy snow showers developing off the Irish Sea. This is indicated on 12Z UKMO, GFS & ECMWF Guidance..

Medium Term also looks bitterly cold with a renewed Easterly flow.. I have just one question however, for perhaps John Holmes, Nick F, S Murr, Nick S et al..

ECWMF seems to be a bit out on it's own tonight, with a slower phased evolution to a more potent Easterly flow between T+120 and T+144.. The vast array of other guidance, GME, GFS, UKMO etc seems to suggest a more rapid transition.

Indeed, UKMO has been very consistent on the past two runs regarding this change to a more due Easterly flow later in the week. I know that ECMWF is, by and large, the superior global model. In light of this, which is likely to be nearer the mark? Or are we likely to see a middle ground final evolution?

UKMO seems to be performing very well to Day 5 at the moment:

http://www.emc.ncep..../html/acz5.html

Regards,

SA

[PB22]

The Dutch ensembles: http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Remaining very cold, with the operational and control runs going slightly above the mean for the end of the week/next weekend.