Model Output Discussion: 12Z (22/11/12) And On...

[Frosty.]

A very cold spell is on the way I think but some of the operational

model runs just don't know it yet.

It all shows great potential for a wintry or very wintry spell according to most of the latest model output but I still haven't heard didly squat about a cold outlook from any television or radio media yet, so there must still be a large element of doubt in their view because once they say it, they don't like to backtrack so they will have to be 100% certain before they are onboard, I thought they would already be onboard.

Edited November 23, 2012 by Frosty039

[AWD]

Links not working dude.

Edited post, should work now mate.

Also, UKMO shows the extent of the wind & rain the south could face this weekend;

http://www.meteociel.fr/modeles/ukmo/precipitations/24h.htm

http://www.meteociel.fr/modeles/ukmo/precipitations/30h.htm

http://www.meteociel.fr/modeles/ukmo/precipitations/36h.htm

http://www.meteociel.fr/modeles/ukmo/precipitations/42h.htm

Not looking good for the SW.

[bluearmy]

It all shows great potential for a wintry or very wintry spell according to most of the latest model output but I still haven't heard didly squat about a cold outlook from any television or radio media yet, so there must still be a large element of doubt in their view because once the say it, they don't like to backtrack so they will have to be 100% certain before they are onboard, I thought they would already be.

The media are more concerned with the w/end rain. The cold chat will come sunday onwards.

[Karl83]

Edited post, should work now mate.

Also, UKMO shows the extent of the wind & rain the south could face this weekend;

http://www.meteociel...tations/24h.htm

http://www.meteociel...tations/30h.htm

http://www.meteociel...tations/36h.htm

http://www.meteociel...tations/42h.htm

Not looking good for the SW.

Too true. Looks like a hell of a lot of rain still to come yet.

[Downburst]

It all shows great potential for a wintry or very wintry spell according to most of the latest model output but I still haven't heard didly squat about a cold outlook from any television or radio media yet, so there must still be a large element of doubt in their view because once they say it, they don't like to backtrack so they will have to be 100% certain before they are onboard, I thought they would already be onboard.

you have to remember rmost people are not interested in model runs 8 times a day. Also the met office have a procedure well understood for severe weather. I am curious though where you believe the media would get their sources? James Madden perhaps. I would think the met office forecast will drive the response. Reading it now there is no need to panic the general population just yet.

[Féar Sneachta Bán]

Hi all, I discovered this forum during the cold spell in 2010 and I have been hooked since. I can safely say I'm addicted. Although emotions can resemble a rollercoaster at time, I know there are lots of people who are very passionate about weather and I want to say thanks for all your analysis and opinions! With regard to the upcoming (potential!) cold spell, the approach I take is to find a middle ground, if they are predicting patterns that are too good to be true, then they probably are! There is no doubting that there is cold weather on the way but I remember the same ups and downs before Nov / Dec 2010 and look how that turned out. I think we are very lucky to see charts like these so early in the year and if Jan or Feb turns out to be mild, I think people will give a limb to see charts like these and the possibility of them materialising!! My advice is to sit back and enjoy. Personally, I think we might be in for an exciting 2 weeks which will make the run up to Christmas very seasonal!

Ryan

[Methuselah]

Welcome to netweather Ryan the snowman...

[NorthernRab]

Hi all, I discovered this forum during the cold spell in 2010 and I have been hooked since. I can safely say I'm addicted. Although emotions can resemble a rollercoaster at time, I know there are lots of people who are very passionate about weather and I want to say thanks for all your analysis and opinions! With regard to the upcoming (potential!) cold spell, the approach I take is to find a middle ground, if they are predicting patterns that are too good to be true, then they probably are! There is no doubting that there is cold weather on the way but I remember the same ups and downs before Nov / Dec 2010 and look how that turned out. I think we are very lucky to see charts like these so early in the year and if Jan or Feb turns out to be mild, I think people will give a limb to see charts like these and the possibility of them materialising!! My advice is to sit back and enjoy. Personally, I think we might be in for an exciting 2 weeks which will make the run up to Christmas very seasonal!

Ryan

Abair ainm breagha a th'ort - failte gu Netweather

Hopefully there'll be many a Snowman for Dublin this winter!

[LomondSnowstorm]

The short ensembles for De Bilt are out:

[Frosty.]

The media are more concerned with the w/end rain. The cold chat will come sunday onwards.

Yes, countryfile will be very interesting..

Another deluge spreading north tomorrow with yet more flooding, the rain probably less intense than yesterday but more persistent, perhaps 18 hours of non stop rain which is just another nightmare for many people, then this mass of rain spreads up to scotland for sunday with southern britain becoming drier, probably more wet and windy weather on mon/tues across the south/east.

[Frosty.]

you have to remember rmost people are not interested in model runs 8 times a day. Also the met office have a procedure well understood for severe weather. I am curious though where you believe the media would get their sources? James Madden perhaps. I would think the met office forecast will drive the response. Reading it now there is no need to panic the general population just yet.

I would have expected a hint or two by now, the models have been firming up on this cold outlook all week, and will continue to.

[Ian Brown]

Interesting ensembles from the ECM. The OP is out of kilter with the majority of members at various stages. More runs needed...

[bluearmy]

The short ensembles for De Bilt are out:

not a shock to see the op go from the coldest member sat night to the warmest, wettest and windiest on monday. one for the bin in its latter stages. the mean is far more resolute in holding the euro trough just to our east, sinking slowly. as i said before, if we can get snowcover at the outset next weekend, a cold slack trough to follow will be just perfect for a freeze. without the snowcover, it may rather murky, grey and v cold without any really low overnight temps.

noaa cpc 8/14 dayer doesnt have a vortex segment to speak of on the canadian side. it keeps the mean euro trough v close to the se of the uk.

[MKN]

Tbh frosty if I was the met/bbc I wouldn't be commenting on anything past +72. Its been clear to me that FI is closer than usual hence the chopping and changing and the Ups and downs of peoples moods in here. Yes cold looks likely especially further north. But for most of Britain snow is far from guarenteed as the gfs has shown tonight, it never takes much to put a Spanner in the works. Hopefully by sunday/monday we will have a firm idea on how the later part of next week will pan out.

[PubliusEnigma]

In a week's time with the atlantic high sinking south, and plenty of lows tracking around it

before sinking south the West and south west could see a lot of sleet and snow, with snow

almost anywhere. Most at risk of rain in this set up would be Ireland.

[LomondSnowstorm]

not a shock to see the op go from the coldest member sat night to the warmest, wettest and windiest on monday. one for the bin in its latter stages. the mean is far more resolute in holding the euro trough just to our east, sinking slowly. as i said before, if we can get snowcover at the outset next weekend, a cold slack trough to follow will be just perfect for a freeze. without the snowcover, it may rather murky, grey and v cold without any really low overnight temps.

noaa cpc 8/14 dayer doesnt have a vortex segment to speak of on the canadian side. it keeps the mean euro trough v close to the se of the uk.

NOAA seem not to have much faith in the operationals at the moment, which is probably a good thing since the ensemble means look more promising than the operationals at present.

Snow cover is crucial to marginal setups when there's low pressure around, just gives that added edge and allows a localised cold pool to keep things the right side of marginal. I'm sure somewhere will have decent snowcover by next weekend, but we really don't have enough details to say for certain where is best favoured etc.

[sundog]

I would have expected a hint or two by now, the models have been firming up on this cold outlook all week, and will continue to.

On the irish tv forecast they said today -very cold weather for next week under a polar airmass.

[kumquat]

I would have expected a hint or two by now, the models have been firming up on this cold outlook all week, and will continue to.

I expect Ian F has been gagging to talk about the potential cold spell on our local forecasts, but reasonably and rationally, in the South West especially, it has been the rain that has had to take priority. Folk have lost their lives and plenty of damage has occurred from flooding over the past week. I've never seen so much water around tbh, and my back bedroom window view of the Frome river resembles a lake.

Ian did hint here that there is discussion about the coming cold at the MO a day or so ago so I think we can say it's not off their radar by any stretch but the shorter term more pressing stuff has been, rightly so, holding their attention and dominating the public-facing forecasts.

NAE 12Z shows accumulations of over 20mm here in the west country again over the next 48hrs from the encroaching low system and possibly more to come on Sunday night so things not over yet by any stretch of the imagination.

Looking at the projected accumulations getting bigger and bigger the further southwest you go, I'd be especially concerned for anybody living in flood prone areas of Devon and Cornwall, Somerset, Gloucestershire and South Wales - actually any areas facing the onslaught of these ppn bearing low systems.

NAE 12z from Weatheronline: (hope it's ok to post this mods?)

Edited November 23, 2012 by kumquat

[Methuselah]

And in twenty minutes, we'll be going through it all again: the 18Z is due any time!

[TEITS]

When we have such inconsistency from the model output I tend to try and find a mean between all the output over the past 24hrs. So far we have seen everything from bitterly cold convective E,lys with 850s as low as -12C to a N,ly flow with 850s around -5C.

Now I would love to say the bitterly cold E,lys are likely but being unbiased these have been rare in the model output over the past few days. The common prediction from the models is a less cold NE,ly flow with upper temps ranging around -5C. This can clearly be seen on the GEFS ensembles.

http://cdn.nwstatic.co.uk/ensimages/ens.20121123/12/t850Cambridgeshire.png

Much can change over the next few days but for me the bitterly cold E,lys are a rank outsider at the moment.

[Barry12]

This will be a post on the rain over the weekend possibly causing Flooding in places.

The GFS has a band of rain moving from the South-West on Saturday morning, by 9am it will have reached south coasts, by 12am it will have pushed further south reaching London. Although the south coasts will be bearing the brunt of it, especially the south west. By 3pm it will be raining in south and mid wales, with Cardiff potentially getting the worst of it. By this time the south west will get a bit of a breather, with lighter rain, although it will start turning heavier in the south east. Although, the very far west will still be heavy. By 6pm, the rain will have spread to the midlands, with Cardiff still bearing the worst of the rain, apart from the very far south west which could be getting very heavy rainfall. By 9pm large parts of the south west and south wales, in particular Cardiff, could potentially recieve very if not torrential rain. Parts of north wales could also recieve heavy rain, although most of it shouldn't be too heavy. It will also have reached the North of England by then, although compared to the south the rain shouldn't be too bad. Not as bad as the south west, but there will still be heavy rain in London too. Norwich another place potentially recieving heavy rain. By midnight, the heaviest rain will still be in the south west and Cardiff, the midlands also recieving heavy rain by this point. By 3am the heaviest rain will be in Nottingham, Lincoln and parts of the east coast. It should be dry in the south west and only light rain still lingering in south Wales. By 6am much of the same, with the worst of the rain lingering in Nottingham and Lincoln. By 9am on Sunday, the rain will have cleared Wales, the south of England and the midlands, with rain in the North of England, North East of Scotland and the south west of Ireland (get your umbrella out snowstorm)

By 9am much of the same, although rain will have pushed further North in Ireland, the east remaining dry though. By 3pm the rain will have moved back into the south west of England and the south of Wales, although nowhere near as heavy during satuday. The East of Ireland now getting some rain. At 6pm South West Ireland could recieve some heavy rainfall. By 9pm the south of Ireland getting the worst of the rain, with the South East also getting heavy rain. Much of the same occurence at midnight. By 3am on Monday morning, much of the same still, although North wales now recieving the worst of the rain. 6am, still heaviest in North Wales. Potentially some heavy in Yorkshire

9am, north of Wales and the north of England still recieving the heaviest of the rain. By noon on Monday, again North Wales getting the worst of it, potentially flooding caused here as heavy rain will have been falling for hours now. I will post some further updates on how the rain progesses through Monday later, all I will say is that Manchester may recieve some heavy rain.

In conclusion, the south west and south of Wales will get most of the rain, these places will be the most likely places any flooding will occur. The midlands and North of Wales also recieving considerable amount of rain but shouldn't be as bad.

[Jason T]

Yes, countryfile will be very interesting..

Another deluge spreading north tomorrow with yet more flooding, the rain probably less intense than yesterday but more persistent, perhaps 18 hours of non stop rain which is just another nightmare for many people, then this mass of rain spreads up to scotland for sunday with southern britain becoming drier, probably more wet and windy weather on mon/tues across the south/east.

I just wonder though Frosty, If they will even dare correctly forecast the up coming week. Still early days for nailing how this will pan out. Admittedly the block showing East is very strong,Just these pesky lows, are creating problems. However the output through out over the past days has been,Well mind blowing. Its clear to state East side will deliver, but just to what depth. I believe any Televised forecasting between now and Sunday will be (Options open). The beauty of our forecasting in the UK is just (Really) a roller coaster as being an Island our options are really open.

[ukpaul]

I just wonder though Frosty, If they will even dare correctly forecast the up coming week. Still early days for nailing how this will pan out. Admittedly the block showing East is very strong,Just these pesky lows, are creating problems. However the output through out over the past days has been,Well mind blowing. Its clear to state East side will deliver, but just to what depth. I believe any Televised forecasting between now and Sunday will be (Options open). The beauty of our forecasting in the UK is just (Really) a roller coaster as being an Island our options are really open.

They may well do another forecast split on probability lines suggesting the different possible outcomes and their likelihood.

[Severe Siberian icy blast]

I have a feeling that there may be some "wintry" precipitation on the northern flank of that low pressure next tue. Especially high ground at night and under heavy ppn.

[Catacol]

Ian did hint here that there is discussion about the coming cold at the MO a day or so ago so I think we can say it's not off their radar by any stretch but the shorter term more pressing stuff has been, rightly so, holding their attention and dominating the public-facing forecasts.

I know someone whose wife is quite big at the MetO and apparently all the main forecasters are away next week at a conference. We may well see a rather "lighter" than average week from them while these folk are away!