General Model Output Discussion

[kold weather]

I would add John there has been a real trend to strengthen the jet, its been on just about every recent run over the last 36hrs, the key is exactly where the PV ends up, the further west the better it is for the UK. As you say though forecasting cut-off lows quite frankly is next to impossible at this range!

I'd also say in this set-up if the jet does end up being stronger then the risk for a big snow event somewhat like what BFTP has been talking about is quite possible from the SW but small shifts could alter that risk in a big way.

Right now I'd have to favour a mean SE flow from the 10th onwards, possible attacks from the SW as well...but we don't want too much energy in the jet or the PV to be too far east. If we can escape that risk point then the whole pattern should start to feedback and I'd imagine we'd be locked to the 20th...

Neil, yeah plenty of time for things to change, have to admit the 18z ensembles much less keen on a easterly flow of any strength, most do still drag in a slack easterly though...

[Duane S.]

I think that despite even the beeb forecasting a snow-fueled armagedeon on Friday, the LP responsible will simply be too far away from us come then. The ECM probably has it about right, still a cracking chart that mind you!

Anyway, we've got plenty of snow to get through first in various quarters of the country.

[kold weather]

Ensembles are a bit of a mess to be honest in the longer range, certainly less agreement then there was in the 12z, probably suggestive of a broad pattern change aloft occuring and the ensembles having a bit of a hard time to adjusting to it.

Most runs are cold out to 240hrs, then considerable differences occur because of the difference in the jets strength and position. More then a few have big snow events as well...mind you most have downgraded the easterly..

However as I said many days ago, it doesn't really matter because regardless of the set-up we will have the cold pool over us till at least 192hrs even according to the very most progressive runs...very long time away but I like to push myself as far as I can go, as GP has proved its possible to get a grip on the much longer pattern...

[danm]

Any chance it can be upgraded again and this was just a blip in the water , so to speak?

Hope so. The outlook this week is still fantastic compared to what we are used to. But when a carrot is dangled in front of you (GFS 12z, ECM, UKMO) you undoubtedly get excited, then when it downgrades you naturally get disappointed. The ECM had a fairly big downgrade on one of its runs prior to the December cold spell, then came back on board on the next run. So who knows what the GFS will do on subsequent runs? It may not go back to what it showed on the 12z, but it may move the low a bit further north again to something in the middle.

Next weekend is a meteorological lifetime away, and still plenty to look forward to this week. Snow events will pop up for most of us.

[Bobby]

FWIW the GFS control run shows the other option, with the Atlantic attempting to come back in, probably a big snow event but the less cold air wins out in the end, still not what I'd call mild mind you BUT a far cry from the 18z synoptics.

GlacierPoint says that we can expect battlegrounds heading into Mid Jan and he's been bang on so far I think. So this scenario is very plausible, the ECM also hints at it.

Some good discussion on this in the In Depth thread. Don't think this cold will give up the fight easy though and may well win, at least for a time. This set up won't go on forever of course.

[Snow Queen one]

Knew that snow dumping was too good to be true for my area. Didn't want it anyway. I have seen this before though the GFS picks up on something then drops it only to come back to it at the last minute so maybe there is still hope after all. This cold spell has been picked up well by the models.

[swilliam]

FWIW the GFS control run shows the other option, with the Atlantic attempting to come back in, probably a big snow event but the less cold air wins out in the end, still not what I'd call mild mind you BUT a far cry from the 18z synoptics.

I have had a quick look at all members 192-384 to look for some trends.

A lot of the members have lows trying to undercut the high with varying degrees of success. in some cases it results in some very impressive synoptics (with extensive Northern blocking) but not that cold uppers. If a cold pool remains over SE Europe then that can get advected over us and in a couple of cases a cold easterly is reestablished. Sometimes the high retreats to SE Europe. There are a few members that just sinks the high with inevitable results. What is not shown in any members is retrogression of the high towards Greenland and then a reload from the North - so we can possibly rule this out even in fi. So for any reload we will probably need to look to the SE and then the East. Best members if you want to look at some nice charts are 1,3,7,8,16, and especially 15 (other than the ones that are not in FI of course - can't even say eye candy now!)

[kold weather]

The ensembles certainly suggest a battleground is quite possible, I suspect its quite probable evoluton to evolve but we shall see. What we need to see is the parent low head NW, if we see that at any point then a new low should cut-off thanks to the southerly flow and bingo you have a snow threat.

Control run bit of a pig past 240hrs (compared to other runs anyway!), shows my real fear of what could evolve from the pattern the 18z suggests....still below average upto 300hrs but not exactly the stunner the 18z op is...

[Duane S.]

Hope so. The outlook this week is still fantastic compared to what we are used to. But when a carrot is dangled in front of you (GFS 12z, ECM, UKMO) you undoubtedly get excited, then when it downgrades you naturally get disappointed. The ECM had a fairly big downgrade on one of its runs prior to the December cold spell, then came back on board on the next run. So who knows what the GFS will do on subsequent runs? It may not go back to what it showed on the 12z, but it may move the low a bit further north again to something in the middle.

Next weekend is a meteorological lifetime away, and still plenty to look forward to this week. Snow events will pop up for most of us.

The trouble is that infamous December ECM downgrade was a bit different because it was so sooooo out of kilter that there was something quite evidently wrong with it. And the way it suddenly sprung back added more weight to that. This time around the ECM looks plausable I'm afraid. It takes away the threat of what the Countrytracks forecast was hinting at for Friday for most but there still remains an incredible time of cold and snow ahead of us.

And you are right when you say things could change. That they will but I think the ECM has it right on this occasion.

[danm]

The trouble is that infamous December ECM downgrade was a bit different because it was so sooooo out of kilter that there was something quite evidently wrong with it. And the way it suddenly sprung back added more weight to that. This time around the ECM looks plausable I'm afraid. It takes away the threat of what the Countrytracks forecast was hinting at for Friday for most but there still remains an incredible time of cold and snow ahead of us.

And you are right when you say things could change. That they will but I think the ECM has it right on this occasion.

Youre right about the ECM backtrack on that occasion. I was actually talking about the current downgrade by the GFS, the last ECM run at 12z was actually still ok for the SE, just less good for those further north and west hoping for heavy snow.

[Optimus Prime]

More local 850s from Monday - Sunday;

Puts this cold spell into perspective. Nothing like it since 1991

[danm]

More local 850s from Monday - Sunday;

Puts this cold spell into perspective. Nothing like it since 1991

Looks fantastic. Is this from the 18z?

[Optimus Prime]

Looks fantastic. Is this from the 18z?

Yup

[casparjack]

Yup

I agree, everything I have looked at tonight (in the reliable timeframe) looks superb...

Seems that many people wouldn't be happy unless glaciers were being predicted to start running along the M4 towards London!!

Let's just enjoy it, as many have said, it will be a very long time before we see these synoptics again - in the +24 to +96 range.

[patrickshere]

I agree, everything I have looked at tonight (in the reliable timeframe) looks superb...

Seems that many people wouldn't be happy unless glaciers were being predicted to start running along the M4 towards London!!

Let's just enjoy it, as many have said, it will be a very long time before we see these synoptics again - in the +24 to +96 range.

I'm afraid that the glaciers will most probably be moving in the other direction anyway. Glaciers from the west would be quite a treat. Haha..

[pyrotech]

Looking at the fax charts i can still see the possible snow storm for the South and east. Its touch and go but it certainly not out of the question and i can see GFS playing with this again in near future runs, as i feel its actually under progressed it.

The percipitation i was expecting to influence further westwards towards swindon ( still no good for me) and yet its gone the other way but i am not sure thats the end of the story yet. The models are struggling with what the low pressure will do over southern Europe. Its effects will be quite widespread and effect alot of key issues. Its very unsettled over Spanish Islands towards Italy. High pressure dominant over Both Ne and E Europe. Then a high trying to build from UK towards Greenland. The unsettled Southern European weather will in my humble opinion effect the Uk as we move towards the 96hr - 168hr mark. The models have moved away from the effects that the southern low could potentially have but i would be surprisd if by 18z Tuesday we do not see the models at least play with it again. Its a very fluid situation and i think we will see alot of adjustments in the forthcoming runs and this fantastic cold spell will continue to make headlines.

Or am i just hope casting and seeing ghost potential in the charts which is very easy to do in a setup like this with such deep cold embedded over the UK and snow potential.

[danm]

No one seems to be here, but ill just state that the 00z is a bigger downgrade than the 18z for friday/saturday. Seems like a trend to push the high further south and east is developing. There is still a potential for some snow in the SE at the weekend, however if the trend continues even here will likely be dry. But tuesday to thursday seems fairly good for snow showers, and still bitterly cold by the looks of it. We'll see how the other models and the GFS fares in the coming days.

i dont't know how u can saythat upper air temperture are cold throughout the run until the 20th you cnt expect much more its in f1 but its still cold and time to chance for snow. cold outlook pretty dry after friday!!!

Well I meant a downgrade as far as the snow potential for the weekend as the low is even further south and quite a bit further east than on the 18z. But like I said in my previous post, it's still bitterly cold and there's good potential for snow from tues to thursday. In fact from tomorrow for northern areas. And still time for next weekends outlook to change again.

[Uncle_Barty]

guys it's FI ("eff-eye") and nothing to do with Messrs. Button, Hamilton and co!

The fact it's still a few days away shouldnt raise too many alarms at this stage, though of course it's possible that GFS has picked up on something.

Will wait to see what the like of GP/Chiono have to say as to how it fits with the latest teleconnections....

[SMU]

people are making the mistake of looking days away when the snow is upgrading over the next 48-72

S

[snow drift]

After viewing the latest output, I would say that this coming week will be similar to last week. The differences being the front moving down on tues give some snow but not much to most. The east side of the country looks to have the better prospects but for the majority a very cold and mainly dry week.

As like last week everyone looking 5/6 days ahead and looking for potential heavy snow but as we all know it is difficult to predict at that range. I would just ask people to remember not to get to down if this potential does not materialise as this thread will become a nightmare of people bickering and throwing toys out of prams.

[Michael Fishermans Friend]

ECM 0z looks pretty good to me - and continues the cold spell into next week with HP in some form either tou our NW, N or North East, looking pretty good going by that model!

[MKN]

people are making the mistake of looking days away when the snow is upgrading over the next 48-72

S

Not for here its not, yesterdays 12z was fantastic now were back to a bit of light snow at best over the next week.

[carinthian]

Good morning,

These are great winter charts, whether it snows or not. Charts well into the future that produce a prolonged cold spell not seen for many decades !!!

Some of the posts make me upset on here , so going to chill and not read anymore.

Enjoy the cold and snow for some over there, a proper winter is to be had for all.

C

[Liam J]

in the short term there is potential for snow anywhere from today, through to thursday.

a cold front is moving south across scotland and looks like it will intensify on its journey southwards overnight to give places a fresh covering.

looking over gfs ppn plenty of showers/bands of snow moving across after that for the majority.

what we must not forget is the severe cold outlook snow or no snow, its going to be colder than may will ever remember and that in itself can cause major problems and add in snow with it looking at some pretty severe winter weather.

wait until wed/thurs for the weekend outlook we all know how long away 5 days is in weather and models!

[johnholmes]

More local 850s from Monday - Sunday;

Puts this cold spell into perspective. Nothing like it since 1991

quite the correct comment-this is going to be the coldest spell some on here will ever have known-for the oldest amongst us then I MIGHT yet rank in the top 10 we have known!