Model Output Discussion

[damianslaw]

As I said in my earlier post, the eventual evolution as we head through next week is for polar continental air and associated easterlies, the 8th Feb has been a strong signal date for the very deep cold air to move in, so still a good week and plus away. In the meantime, middle of next week will no doubt see a bit of a battle between the atlantic and the continent and we will be sat on the battle line so to speak, expect the UKMO to reflect this tomorrow in its FAX chart for Wednesday, thereafter it is going to be a case of just watching those heights to the NE build and build and advect our way.

I'm secretly hoping for a proper battleground situation before we get the real cold, a good bout of frontal snow next week would set up us nicely for the bitter spell. Easterlies are very common in Feb and this evolution is more likely at this stage in the winter than earlier stages, hence why I have alot of confidence in an imminent very cold spell indeed and given that it is Feb, a greater chance of it sustaining in situ.

[Duane S.]

Just seen the 18z, not a bad run I suppose, yeah I suppose I would take it.

Joking aside, that is, I think, the best run I have ever seen from the GFS Operational.

The incredible news is that it is no outlier either. OBVIOUSLY it was one of the colder runs but had a surprising amount of support.

This is NOT getting further away despite what some are saying. Cold, getting colder, then a few required (possibly nervy) days quite mild(er) before it happens in just over a week's time.

As for the UKMO, I am a bit nervous about it I will admit as it COULD be on to something but even if it is I would only view it as (in the worse case scenario) a slight delay and an eventual watered down Easterly. Hope not though when you see what the jackpot is.

I spoke earlier of the potential of a massive linkup, the 18z has obviously listened and I think, as extreme as it is (and it is) this REALLY is plausable. The massive block to the East will start to try to head West, signals are good for height rises over Greenland at exactly the right time and we end up with a sprawling great high pressure sat in the perfect place for us

[flyer]

A little late night viewing from Joe B as to why the models may be playing up

http://www.accuweather.com

Edit might have to make your own way there as the floori filter cuts in on the link

Edit again : try rhis

http://www.accuweather.com/ukie/

Edited January 29, 2010 by flyer

[Guest North Sea Snow Convection]

Agree absolutely with this post. We can't dismiss an outlook just because it looks a bit 'extreme': sometimes extreme uppers like that do occur. Other runs have been hinting at this as well, and with the cold pool as cold as it is to our east scenarios like this should not be taken off the table. Put it this way: if a less cold southerly was shown at +240 hours would people totally dismiss it as well? In reality the 18Z in general looks just as likely as that, perhaps slightly moreso actually.

Not saying it will happen just suggesting that 'it's never going to happen' comments are slightly too dismissive of at least the general pattern shown by the 18Z.

LS

Its amazingly ironic that someone like me that suggests that 18z is 'extreme' and unlikely to happen is called up for being dismissive lol!. One of the coldest rampers on the forum for the last few years...

lol!

It shows how much this place has changed. Unless you subscribe to the next ice age as the only possible outcome then your face doesn't fit anymore.

And I believe still in the colder world rather than the popular warming one

It's so incredibly ironic...really it is....

[pyrotech]

It's a high resolution model used by the UKMet. You can view it here:

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=nae&MODELLTYP=1&VAR=prec&HH=0&BASE=-&WMO=&ZOOM=0

I think you can get better charts than that but can't remember where from. If anyone knows of this please post the link so that people can bookmark it.

Edit: Barb beat me to it.

Try floodwarn http://www.floodwarn.co.uk for NAE charts and satalite pictures, rivercams when heavy rain and snow cams a the snow moves in.

With the models we are back where we were a few weeks ago, trends are the famous words here and although nothing in fi is set in stone as in intensity and length the fact that a trend has set in is what we look for. firstly a model ticking with a trend then the others showing some agreement, but in my opinion we do need the fax charts to show a similar pattern in the timescale. Truly a fantatic 80s style winter setting up again, to be fair both GFS AND ECM have pretty much done ok with trends this year, how often have we seen cold disapear on previous years a we move out of fi. This year models have been pretty damn good a have some on here who look beyond the models capabilities in lrf.

sorry about short post damaged computer in car crash in last snowfall only run on battery now and without some keys for max of 5 mins

Edited January 29, 2010 by pyrotech

[Just Below Zero]

Spot on I reckon. The salting of roads could be the least of our problems once again, especially if the over-populated south gets hit again. Some impressive theories in here and only time will tell I suppose. I must admit some folk have an uncanny knack of being bang right on the timing when it comes to our understanding of climate's intracies (?) however. NAO/AO's, QBO's MMW's all go over my head but RESPECT is due to the good folk such as you who are rarely wrong and when you/they are, more importantly, you EXPLAIN why it did not hit the target. Alternatively you could read the Daily Mail, who are never wrong, so I wonder how long before the headline 'SIBERIAN BLAST approaching' appears

Wintry Cheers

STORMBOY

If the GFS 18Z at 240 plus comes to fruition it will more likely hesdline "SCOTLAND REGLACIATED"

[Paceyboy]

POTENTIALLY a very exciting period coming up. I believe that a continental flow will occur in the next few days following the current northerly.

The UKMO model is causing some worry and to me it is a potential speedbump in the evolution as a whole. I still think that what it shows now would not be disaster, perhaps a more delayed development to a cold/very cold continental flow. I just hope tomorrow morning it starts to agree with the others models between the 120-144hrs time range just to provide a little bit more comfort to us model watchers!

I heard 1:20 rain/snow ratio being mentioned by legendary Mr Murr, however i thought that the maximum was a 1:10 ratio?

[LomondSnowstorm]

Its amazingly ironic that someone like me that suggests that 18z is 'extreme' and unlikely to happen is called up for being dismissive lol!. One of the coldest rampers on the forum for the last few years...

lol!

It shows how much this place has changed. Unless you subscribe to the next ice age as the only possible outcome then your face doesn't fit anymore.

And I believe still in the colder world rather than the popular warming one

It's so incredibly ironic...really it is....

Lol, sorry, I wasn't specifically referring to you. I find your posts to be very helpful and well informed. I just meant to say that the evolution looks less implausible than it would normally look. I don't think it'll verify either, let's face it those charts hardly, if ever do, but -10 - -15 uppers across some of eastern Britain look a distinct possibility. The ensembles support this nicely also, with just a few isolated members going above -5 after the 5th http://charts.netweather.tv/ensimages/ens.20100129/18/t850Fife.png .

Sorry again if it seemed like I was calling you a mild ramper - with a name like North Sea Convection though there should really be no confusion about that

LS

[Guest North Sea Snow Convection]

Lol, sorry, I wasn't specifically referring to you. I find your posts to be very helpful and well informed. I just meant to say that the evolution looks less implausible than it would normally look. I don't think it'll verify either, let's face it those charts hardly, if ever do, but -10 - -15 uppers across some of eastern Britain look a distinct possibility. The ensembles support this nicely also, with just a few isolated members going above -5 after the 5th http://charts.netwea...18/t850Fife.png .

Sorry again if it seemed like I was calling you a mild ramper - with a name like North Sea Convection though there should really be no confusion about that

LS

I do think that a spell such as the 18z suggests is still possible sooner or later in years to come, which would at least match Jan 87 and probably surpass it.

I just don't see it within the context of the current pattern at the current time. Extremest of extreme cold spells have always been rare in the UK. I am talking about Jan 87 high intensity short duration events as opposed to seasonal two/three monthly freezes like 47/63 which reload between Greenland and Scandinavia/Siberia but do not have full throttle intensity throughout although they are more immobilising through their sheer persistence.

However there is no doubt that something like Feb 91 could be round the corner within the context of the factors that we have before us atm.

What the 18z GFS is proposing is slightly colder and more 'extreme' than that imo. And it wasn't the coldest solution in its group either! So something of Feb 91 order is perfectly possible I think. Which is a severe enough cold spell for sure

Edited January 30, 2010 by North Sea Snow Convection

[Duane S.]

Anyone remember this? ECM from 3 days ago. Slightly progressive yes but certainly looks familar...

[TEITS]

Only just viewed the 18Z and my word thats an extreme run, although possible!

For me its very simple if we can get say +162 at +72 with model agreement then the upper temps of -15/16/17C remain possible. The simple reason is what i've been saying for the past few days the cold pool has to back W because it doesn't have anywhere else to go. So rather than saying "18Z will never happen" look and see if synoptically its possible. If it is then upper temps that low remain plausible.

I will add that upper temps of -17C will bring lower max temps than -4C. I reckon in locations such as Kent you would struggle to reach -6/-7C.

As for the UKMO I really can't make my mind up about this. On the one hand its been a real spoiler wrt to E,lys. However only recently you may remember the UKMO disagreed with every run and the Met O/BBC rather strangely backed the UKMO. This is why the BBC were forecasting sub zero max temps and snow when the rest of us sat here and knew the outlook would change the next day. As we remember this is exactly what happened.

So in summary the ECM/GFS/GEM have actually upgraded the E,ly this evening. However I refuse to get excited until we see model agreement at +72.

[Cumulonimbus Tower]

Anyone remember this? ECM from 3 days ago. Slightly progressive yes but certainly looks familar...

Yup, remember it well.... T'was the eve that the models decided to ignore the influance of the northern arm of the jet no???

[LomondSnowstorm]

I do think that a spell such as the 18z suggests is still possible sooner or later in years to come, which would at least match Jan 87 and probably surpass it.

I just don't see it within the context of the current pattern at the current time. Extremest of extreme cold spells have always been rare in the UK. I am talking about Jan 87 high intensity short duration events as opposed to seasonal two/three monthly freezes like 47/63 which reload between Greenland and Scandinavia/Siberia but do not have full throttle intensity throughout although they are more immobilising through their sheer persistence.

However there is no doubt that something like Feb 91 could be round the corner within the context of the factors that we have before us atm.

What the 18z GFS is proposing is slightly colder and more 'extreme' than that imo. And it wasn't the coldest solution in its group either! So something of Feb 91 order is perfectly possible I think. Which is a severe enough cold spell for sure

Especially in light of the winter so far! I think perhaps we all (especially me!) need to take a look at this winter compared to most other winters and see that these synoptics have been rare enough anyway over the last few years. On this day in '82 http://www.wetterzentrale.de/pics/archive/ra/1982/Rrea00119820130.gif hardly awe inspiring after that December/January spell, and that was in one of the 'classic' winters.

I wasn't alive in '91, but I assume it was snowier than anything I can remember (which wouldn't be all that hard!). All I really want tomorrow is the UKMO to come on board and the others to stay on board and keep it at the same date. Easterly convective set ups are very fun to watch on the NW radar, especially if it lasts over 36 hours.

LS

[waynetheweatherman]

Especially in light of the winter so far! I think perhaps we all (especially me!) need to take a look at this winter compared to most other winters and see that these synoptics have been rare enough anyway over the last few years. On this day in '82 http://www.wetterzen...00119820130.gif hardly awe inspiring after that December/January spell, and that was in one of the 'classic' winters.

I wasn't alive in '91, but I assume it was snowier than anything I can remember (which wouldn't be all that hard!). All I really want tomorrow is the UKMO to come on board and the others to stay on board and keep it at the same date. Easterly convective set ups are very fun to watch on the NW radar, especially if it lasts over 36 hours.

LS

I was alive in 91, all i can remember was ice inside the windows (before double glazed days!), and snow here in sheffield about 2 foot deep (seriously), i was only 8, but i remember it well and imo it was the last really bad snowy weather here!

[dave79]

I was alive in 91, all i can remember was ice inside the windows (before double glazed days!), and snow here in sheffield about 2 foot deep (seriously), i was only 8, but i remember it well and imo it was the last really bad snowy weather here!

Feb 91 was the best event I've known, I remember a full week of snow blizzards, drifting the lot, even our school was shut for a couple of days, I remember walking home from school, when we got sent home, NO kidding the snow was as deep as I've ever seen it round my way. If this coming spell is anywhere near as good as that then some younger users maybe in for a nice surprise.

A question for the model watches, how likely in terms of a percentage could we see an event like this occuring in the coming weeks?

Edited January 30, 2010 by dave79

[LomondSnowstorm]

Feb 91 was the best event I've known, I remember a full week of snow blizzards, drifting the lot, even our school was shut for a couple of days, I remember walking home from school, when we got sent home, NO kidding the snow was as deep as I've ever seen it round my way. If this coming spell is anywhere near as good as that then some younger users maybe in for a nice surprise.

A question for the model watches, how likely in terms of a percentage could we see an event like this occuring in the coming weeks?

Difficult to put a percentage on it, and I'm sure more experienced posters will give you a much better idea, but I'd say that a set up similar to '91 is probably around 15/20% at some point. By that I mean synoptically similar with similar uppers, not neccesarily the same amount of snow or the same distribution either. That is based on the latest ensembles and the general outlook of the major models at the moment, though as BFTP says it needs to get to +72 hours before the chances of that really cold pool reaching us become realistic.

I'd also say a 50% chance of a potent easterly, an 80% chance of weather patterns dominated by high pressure to our north and a 95% chance of a continental flow for 36 hours at some point between now and the 8th.

LS

[danm]

Just to let u guys know...we had a heavy snow shower in Canary Wharf, London this afternoon. If it can snow here in the centre of London when it isn't even that cold then surely there is good potential for late next week for some decent snow.

[Jack Wales]

Feb 91 was the best event I've known, I remember a full week of snow blizzards, drifting the lot, even our school was shut for a couple of days, I remember walking home from school, when we got sent home, NO kidding the snow was as deep as I've ever seen it round my way. If this coming spell is anywhere near as good as that then some younger users maybe in for a nice surprise.

A question for the model watches, how likely in terms of a percentage could we see an event like this occuring in the coming weeks?

There is still a lot of power in the jet stream and some minor changes could see us under mild synoptics. As for next week I think it hangs in the balance, probably 50/50. As for the week after (FI) I think the GFS 18z has only a negligable chance of comming off but the indications are favourable for a colder spell, especially as the AO is set to plunge.

[dave79]

Difficult to put a percentage on it, and I'm sure more experienced posters will give you a much better idea, but I'd say that a set up similar to '91 is probably around 15/20% at some point. By that I mean synoptically similar with similar uppers, not neccesarily the same amount of snow or the same distribution either. That is based on the latest ensembles and the general outlook of the major models at the moment, though as BFTP says it needs to get to +72 hours before the chances of that really cold pool reaching us become realistic.

I'd also say a 50% chance of a potent easterly, an 80% chance of weather patterns dominated by high pressure to our north and a 95% chance of a continental flow for 36 hours at some point between now and the 8th.

LS

I'd also say a 50% chance of a potent easterly, an 80% chance of weather patterns dominated by high pressure to our north and a 95% chance of a continental flow for 36 hours at some point between now and the 8th.

I like the sound of that - maybe this is the year were we see something simaler to that event of feb 91, fingers crossed anyway.

[LomondSnowstorm]

There is still a lot of power in the jet stream and some minor changes could see us under mild synoptics. As for next week I think it hangs in the balance, probably 50/50. As for the week after (FI) I think the GFS 18z has only a negligable chance of comming off but the indications are favourable for a colder spell, especially as the AO is set to plunge.

The power in the jet doesn't worry me, as long as it is heading south again and at a favourable nw/se axis. e.g. http://www.wetterzentrale.de/pics/Rtavn1381.pngThe UKMO looks different though http://www.wetterzentrale.de/pics/Rukm1441.gif The trough is further north and pushing east towards us, something which doesn't appear to be supported by the other models or BFTP's prediction of the jet tracking a bit further south as the month goes on. The ECM backs the GFS as well http://www.wetterzentrale.de/pics/Recm1441.gif as do the ensembles http://www.wetterzentrale.de/pics/Rz500m6.gif

LS

[cj114]

I do think that a spell such as the 18z suggests is still possible sooner or later in years to come, which would at least match Jan 87 and probably surpass it.

I just don't see it within the context of the current pattern at the current time. Extremest of extreme cold spells have always been rare in the UK. I am talking about Jan 87 high intensity short duration events as opposed to seasonal two/three monthly freezes like 47/63 which reload between Greenland and Scandinavia/Siberia but do not have full throttle intensity throughout although they are more immobilising through their sheer persistence.

However there is no doubt that something like Feb 91 could be round the corner within the context of the factors that we have before us atm.

What the 18z GFS is proposing is slightly colder and more 'extreme' than that imo. And it wasn't the coldest solution in its group either! So something of Feb 91 order is perfectly possible I think. Which is a severe enough cold spell for sure

Feb '91 was one of those times when even Central London had around 5". I remember it well as it took 6 hours to get home from CL in a journey which would normally take half an hour.

I am not great at following patterns but I cannot foresee this happening again. There is a lot of time between now and the 8th for things to change drastically.

I think we have had a good Winter so far, but enough is enough as far as I am concerned and suspect that Europe will now bear the brunt of any upcoming cold spell.

I'll get my Coat. lol

[KTtom]

You have to laugh, or cry, at the models sometimes! Just as the GFS produces an almost identical medium term run to the 12z ECM with a battle royal with a block to the NE and weather systems trying to push up from the SW, the 00Z ECM totally ditches the idea and blows the block away!

UKMO is even worse, in fact is miles away from cold at +120 and +144.

There is a massive scatter on the GFS ensembles for London, but overall no where near as promising as they were.

[billy]

You have to laugh, or cry, at the models sometimes! Just as the GFS produces an almost identical medium term run to the 12z ECM with a battle royal with a block to the NE and weather systems trying to push up from the SW, the 00Z ECM totally ditches the idea and blows the block away!

UKMO is even worse, in fact is miles away from cold at +120 and +144.

There is a massive scatter on the GFS ensembles for London, but overall no where near as promising as they were.

Hi , yep a horrible ukmo again this morning . GFS gets there in the end . I have a bad feeling about this now , especially with last nights fax charts backing yesterdays raw ukmo output ,and this mornings ukmo seems even worse. GEM looks good this morning though. UKMO seems the most consistent model at the moment though , which is a bit worrying given its output again this morning

[Eugene]

the 00Z ECM totally ditches the idea and blows the block away!

No wrong it doesnt at all and if that is a convincing atlantic breakdown run to you then you obviously havent lived through mild atlantic dominated winters before, no worries from me at all it will stay cold for weeks on end just like it has, models always have wobbles and come good in the end, the ensembles are still COLD.

[stratty]

one extreme to the other....................the charts are no way near as good as last nights..............gut feeling: tha chance of a beasterly is diminishing