Winter Model Discussion 18Z 13/1/13 onwards.

[Coast]

First thing in the morning and we are already at each other today? Wouldn't it be nice if we could have a day in this thread where people analysed the model output rather than each other please?

[IDO]

So really you're just speculating then?

In one sentence you say "ECM would deliver transitory snow for much of England and Wales and nothing more"....Then you say

"Actually there is a good chance that things will shift south agin as I alluded to re the trends. I wouldn't actually be surprised if the whole lot drops into France." .....and then you go on to say

"but the charts here and now this morning largely suggest rainfest or England and Wales after a period of snow. Midlands northwards, would likely do better".

Crikey i'm both exhausted and confused reading your post! I suspect others are as well.

But thanks for the clarity!

And are u referring to Friday's charts, Saturday's or just the whole runs?

I think what we have to be aware of is that it is very marginal. Yesterday the Country saw some area get 15cm plus whilst others (me) just rain. Look at the latest Fax:

Last night's for the same time:

Big changes. This is a rapid changing situation.

[NorthernRab]

If we continue to get cold charts at the end of FI that to me suggests a locked in cold pattern. This is starting to occur. Obviously the synoptics and fine details will change but that chart shows a meridional synoptic and we want these to show up rather than hints at returning to a milder setup.

That's fair enough. Apologies for my last post as there was supposed to be a smiley at the end, came across as rather caravany in the end!

I do however think the until we know at all what's going on regarding the CV and pressure over Scandinavia / the Atlantic, we'll see wildly fluctuating projected synoptics being throw at us for the end of the month, even if they are somewhat stable for now.

[Severe Siberian icy blast]

GFS continues with its relentless pursuit of the UK (as per Dec) at the end of the Atlantic train. All in FI of course so if it is wrong at least it has been consistently wrong. A very north south split for this type of pattern. The south may get transitional snow events, the north and higher ground should have snow fields. Late in FI we try to get another cold incursion from the NE, till another cyclonic westerly shifts the cold back NE.

UKMO still showing a better undercut but again that looks likely to be relatively poor for the south, for laying snow. The track may change so hypothetical, but any snow to a relatively quick thaw for south.

ECM is also suggesting that north/south split for snow this weekend and also follows the Atlantic train route. The north should have plenty of laying snow; again the south more transitional.

All marginal at the moment so possible changes likely either way. Much like this snow event just gone.

Whatever synoptically we get it looks like remaining colder than average for some time. GFS at T384:

In the short/medium term all models appear to be in agreement that an easterly is doubtful due to the PV lobe migrating from the US to the Atlantic and PM shots are are main source of cold via cyclonic westerly's. For this to also favour the south we would need the UK trough to continue to shift south and all models are hinting at this. Then possibly a good pattern for the full effects of the SSW, to give the UK a memorable Feb.

Again you are wrong regarding the gfs , transitional snow event for the south is so wrong I had to reply , it gives a 24HR snow event this Friday into sat , how is that transitional ??? Certain ppl are completely underplaying the potential in the charts this morning, the gfs has took a Hugh step this morning , the ukmo is rock solid and the first one to pick this wkend up and for me is the best model in the world at the minute for its consistentcy, and the ECM keeps the theme with southerly tracking lows and snow for MANY

Edited January 15, 2013 by Severe Siberian icy blast

[swfc]

First thing in the morning and we are already at each other today? Wouldn't it be nice if we could have a day in this thread where people analysed the model output rather than each other please?

Its PMT coast.Pre model trauma!!!!

[jessandjon]

When people say poor for the south, can we clarify please that they are talking about the weekend....and not about the front that stalls over the west Friday giving the sw 12-24hrs of snow first....

Very good point!!!

[nick sussex]

I think the problem is you're rarely going to find the perfect set up for the whole of the UK, invariably one location does better than another.

So of course taken at face value you're more likely to avoid a thaw upto 144hrs the further north you are, but whilst pressure remains reasonably high to the ne then you always have that margin for error in the outputs in terms of where the jet will be tracking.

I doubt very much if even the UKMO have any idea how this will play out in terms of how much snow, if it stays as snow and who is most favoured at this time especially for the second attempt by the Atlantic.

[Timmytour]

So really you're just speculating then?

Let's face it....everyone is! Even the models! It's a question of whose speculation you give most credence to....before it becomes a question of who was closer to the actual outcome in the end.

The best snow events for the south imo come from the East. attacks from the west can deliver the goods, but only in a transient form most of the time. A tracking of the lows further south may see us missing out altogether this time, but provide plenty of opportunities in the weeks ahead. A tracking further north might give copius amount for the south...but might also mean, by and large, an end to further chances.

[Iceberg]

First thing in the morning and we are already at each other today? Wouldn't it be nice if we could have a day in this thread where people analysed the model output rather than each other please?

Sme got rain and so are negative, some got snow and so are very positive.

Yesterday is not Friday or the weekend. Yesterday in many ways was more complicated.

This doesn't mean that anything is nailed on though.

Finally can people give an indication when talk about model runs where on the model runs they mean as they tend to be cold, snowy, marginal at vary times for days on end.

Sorry lots of oneliners

[Liam J]

Some quite amazing charts on offer this morning which I'm sure wouldn't look out of place sitting amongst the likes of 47/62/63 - http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=120&carte=1021 Love this UKMO chart - Sub zero for many with severe windchill and blowing snow!

The T144 charts on the ECM & UKMO would create significant blizzards across central and northern areas with power cuts, blocked roads etc. http://www.meteociel.fr/modeles/ecmwf.php?ech=144&mode=1&map=0&archive=0 http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=144&carte=1021

GFS also less progressive bringing in the less cold air than previous runs, certainly nothing mild in the foreseeable with further reloads possible from the north east, perhaps we are on the verge of experiencing something not seen since the 70's or 80's?!

At this stage confidence is very low in the detail for the end of the week so as ever use caution, anyone getting excited/upset at the current charts - DON'T as the specific detail will most likely look different again on the next run. Sit back and enjoy watching this one unfold, it's battleground UK!

[MattH]

Can someone pass the anadin's please?...I've got a "forecasters headache"

First off, it is worth to point out that the uncertainty over the broader synoptic evolution is big enough, let alone attempting to analyse the finer details. The first model divergence is regarding Friday at the moment, yes just 84 to 96hrs away. The latest FAX chart for Friday clearly keeps fronts at bay but with a bitter SE'ly flow across most of the UK. This is at odds with some higher resolution models I am looking at including a 10KM WRF model nested in the ECMWF which brings a frontal zone up into the UK during Friday before it fizzles out. Still it would bring a snowfall event for most areas away from Ireland and SW Eng.

The weekend continues to bring up a variety of situations and both amateurs and pro's alike are pretty much in the same boat with regards to how the models will handle a major surge of vorticity and energy into the North Atlantic over the coming weekend. At the moment this is what the 'big 4' do;

http://meteocentre.com/models/compar_models.php?map=eur〈=en&run=00&stn=PNM&&range=glb&hh=120

Clearly the GFS remains somewhat of an outlier in terms of the orientation of the trough and ridge pattern. Clearly the UKMO and GEM are noteworthy for producing a 'slider low' scenario, with the ECMWF not far behind. The GFS is still attempting a breakdown more from a traditional west to east orientation, but I disagree with this prognosis to be honest.

I've yet to see the 00Z EC ENS, out in 20 mins, but these over the last few days have been leaning more towards a colder regime continuing and for that to happen charts like the GEM and UKMO for example need to take place this weekend. Attempting to say where it will and won't snow, or the Midlands will get 20cm but south-west England will get nothing, is, at the moment, essentially pointless. The broader synoptic pattern needs to become established first before anyone even attempts to say where a front will be and what kind of precipitation it will bring.

It is fascinating viewing, but clearly a nightmare at the same time. Some of the charts do have a similarity to the 70's and 80's at times and clearly *IF* some of the charts in question become reality then the end result would be further cold and snowy conditions. I'll comment on the EC ENS on twitter as usual.

Cheers, Matt.

[Coast]

Its PMT coast.Pre model trauma!!!!

Well here is the place for those posts then:

[swfc]

Sme got rain and so are negative, some got snow and so are very positive.

Yesterday is not Friday or the weekend. Yesterday in many ways was more complicated.

This doesn't mean that anything is nailed on though.

Finally can people give an indication when talk about model runs where on the model runs they mean as they tend to be cold, snowy, marginal at vary times for days on end.

Sorry lots of oneliners

Well maybe budgie breeding may be a better hobby.Agree yesterday was marginal given the orientation of the front ete.The weekend however does hold maybe some more organised snow for the southwest and then who nos?

[IDO]

Again you are wrong regarding the gfs , transitional snow event for the south is so wrong I had to reply , it gives a 24HR snow event this Friday into sat , how is that transitional ??? Certain ppl are completely underplaying the potential in the charts this morning, the gfs has took a Hugh step this morning , the ukmo is rock solid and the first one to pick this wkend up and for me is the best model in the world at the minute for its consistentcy, and the ECM keeps the theme with southerly tracking lows and snow for MANY

I should have added that where the front stalls there would be a large dumping of snow. This is likely to be a very small area and probably in the SW. For most of the rest of the south/SE it will be transitional.

Edited January 15, 2013 by i'm dreaming of...

[cyclonic happiness]

The models this morning are fantastic for everyone for potential snow events.

When was the last time we saw 4 lining up one after the other, this could go down as a classic spell.

I know there's a huge amount of uncertainty, but that just makes it feel all the more like an old fashioned winter spell.

Friday is looking good for the western half of the UK and then there are odds and sods of snow events that crop up most everywhere in the GFS.

Overall, the trend is good and we should all be really excited about the coming week, just look at yesterday, both the BBC, and Metoffice forecast rain for my location and it stayed as snow the whole time, dropping 6cms!! Perhaps this year we are all gonna be on the right side of 'marginal' for once?

[Troubleatmill]

I thought i logged into the Southern thread when i logged in lol!

I agree with Siberian blast, there is no transitional snow showing on the GFS this morning bar the extreme Southwest maybe, if you look at the dew points and 850-1000hpa temps from the GFS 00z there is nothing marginal about these:

great run, if snow is what we are looking for, then snow is what would come, bit baffling why some think not?

[Snow and storms]

It does seem to me people are picking up the 500hpa charts, seeing a massive deep area of blue coming our way and assuming this is going to be heavy snow blizzards.

What is actually happening is this is showing the pressure differences of a deep 968 low pressure coming our way which will pump atlantic warmth into our cold weather.

Given that it is already falling as rain/sleet in places and we are under the influence of supposedly cold weather, by the time this reaches us it will almost definatley be cold high winds, heavy rain

and dark grey skies.

[Methuselah]

Okay peeps...Let's draw a line under all this 'I can read charts better than you...' malarkey...T'aint really the purpose of the thread now, is it?

[bluearmy]

It does seem to me people are picking up the 500hpa charts, seeing a massive deep area of blue coming our way and assuming this is going to be heavy snow blizzards.

What is actually happening is this is showing the pressure differences of a deep 968 low pressure coming our way which will pump atlantic warmth into our cold weather.

Given that it is already falling as rain/sleet in places and we are under the influence of supposedly cold weather, by the time this reaches us it will almost definatley be cold high winds, heavy rain

and dark grey skies.

Perfect example - the flow ahead of any Atlantic incursion will be off the continent. That's a completely different scenario to yesterday with low dp's guaranteed. looking beyond initial push is fairly futile for specifics.

[steelermark]

First thing in the morning and we are already at each other today? Wouldn't it be nice if we could have a day in this thread where people analysed the model output rather than each other please?

Agreed but I think people need to put away the imby view of the model runs.It's clear to see the people saying the charts are not as good are in the south of the country. Whilst for the midlands north, if it's lot's of snow your are after, they don't get much better.

Posters need to remain objective on here and save the imby stuff for the regionals. It does get difficult when you get two posters next to each other, with one saying massive downgrade and the next saying massive upgrade.

I can't properly read the charts even after being on here as a lurker for many years, but even I can see the *potential* this weekend could have for some.

[Cecil Hogmanay Melchett]

Amazing charts this morning.The pattern looks solid to me Ian Fergursons thoughts will be worth hearing but pinpointing snow potential will be impossible until thur/fri.

id say some are going to get seriously snowed in come the wknd!!

[BLAST FROM THE PAST]

Hi Steelermark I am from the south so not quite true, I just see the 'improvement' overall and the slowing down of the Atlantic as each run/day passes and the shifting south of the jetstream.

If this trend continues whether 1st attempt 2nd or 3rd snow will be had by most. Temps in south looking to be 0c daytime MAXIMA come Thurs / Fri. Bring on the fronts.

BFTP

Edited January 15, 2013 by BLAST FROM THE PAST

[Hammer]

EC ENS mean cold.

At this time frame the weekend seems an age away but I think whilst uncertainty models are not far off.

[steelermark]

Hi Steelermark I am from the south so not quite true, I just see the 'improvement' overall and the slowing down of the Atlantic as each run/day passes and the shifting south of the jetstream.

If this trend continues whether 1st attempt 2nd or 3rd snow will be had by most. Temps in south looking to be 0c daytime MAXIMA come Thurs / Fri. Bring on the fronts.

BFTP

Not saying all posters BFTP just some.

Either way somewhere this weekend is going to get something not seen since the 70's and 80's and somewhere will be disappointed. That's the weather unfortunately.

The charts, to my untrained eye anyway, do appear to be showing things getting better for more of the country, who knows where we will be by the time the first front actually hits.

[Liam J]

A few tweets from Matt leading on from his last post, sounds good!

Matthew Hugo â€@MattHugo81

00z EC ENS mean is cold and with lows from the Atlantic never moving E or NE, generally having a NW to SE movement, with a SE'ly

Matthew Hugo â€@MattHugo81

00Z EC ENS far more bullish for a front to move into the UK during Fri...Snow would be possible from the W, details highly uncertain though.