Winter Model Discussion 18Z 8/1/13. The hunt for cold (is closer).

[Met4Cast]

Hi when is the next operational you would use to add the the 4 with the cold synoptics?

The 00z, it starts coming out around 3:30am

[bryan629]

Re: Ensembles

The Jet split is a crucial development and if that doesn't happen then the block can't develop and things flatten out, the ensembles are run at a lower resolution so they're probably not able to plot exactly how thats going to take place, hence we're seeing milder runs.

The Operational has had the split perfect for us in the last 4 runs and has consistently brought about very cold synoptics. The ECM ensembles are great for us with few milder runs along with the UKMO model, for the moment, I'd be inclined to side with the GFS op, ECM + Ensembles and the UKMO.

We'll see what happens tomorrow, but tonight, I wouldn't worry TOO much about the GFS ensembles.

Danny you were spot on earlier today about the ensembles, i think they are just playing catch up , you re-assured a lot of doubers just after the gfs12z , and again your are reassuring that its basically nothing worth noting... it has been an extrodinary day model watching and think the build up has over the past few weeks been enthralling.... from what i have read on here the SSW hasnt even kicked in yet , jees god help us when it does .

[blackprince]

The 00z, it starts coming out around 3:30am

Thanks I am nights so I can watch out for them,hopefully someone on here will post them when they come out.

[Great Plum]

I am greatly bewildered by some picking apart various GFS ensembles this evening... As far as I can see, these are the only thing that is not pointing towards a possibly very protracted cold and snowy spell...

ECM, its ensembles, the ECM 32 dayer, MOGREPS (according to social media), UKMO, GFS, the Chinese, Indian and Australian models are all pointing to this.

To then show the control run from the gfs in 8 days time as showing south westerlies just strikes me as daft...

This cold spell is not nailed on, and whilst I understand people's concerns, in my 9 years of being on Netweather, these are possibly the best charts I have seen (at least since 2010!) and the snow could be here within 72 hours!

[LomondSnowstorm]

I don't think the GEFS not being completely onboard is all that concerning in itself, but it does give us a very good reason to remain cautious for the next 24-48 hours at least, and I think it's important that we are wary of the potential pitfalls we still have to overcome.

Having said that, I agree with the post above that we have very good agreement tonight, almost a clean sweep in terms of teleconnections, background signals, Cohen research papers, long range models, ensembles and operational models.

Edited January 8, 2013 by LomondSnowstorm

[Great Plum]

Short ensembles out:

http://www.meteociel.fr/cartes_obs/gens_display.php?x=317&y=150&run=18&runpara=0&type=0&ext=1

Broad agreement until 14th... Fine by me!

[john mac]

Finally caught up!!!! I think the ensembles can be very fickle sometimes, if the models are still showing similar charts by close of play tomorrow then I think we can get excited!!!

[lukusdukus]

they maybe good but with model confidence at an all time low - is some caution not understandable....

[UV-RAY]

I am greatly bewildered by some picking apart various GFS ensembles this evening... As far as I can see, these are the only thing that is not pointing towards a possibly very protracted cold and snowy spell...

ECM, its ensembles, the ECM 32 dayer, MOGREPS (according to social media), UKMO, GFS, the Chinese, Indian and Australian models are all pointing to this.

To then show the control run from the gfs in 8 days time as showing south westerlies just strikes me as daft...

This cold spell is not nailed on, and whilst I understand people's concerns, in my 9 years of being on Netweather, these are possibly the best charts I have seen (at least since 2010!) and the snow could be here within 72 hours!

Agree GP, but Blighty being Blighty we have to remain wary. Roll on th 00z, I think I'll set my alarm for this run, enthralling stuff regardless of the outcome.

[AWD]

18z Ensembles;

[Rocheydub]

GPlum... Yes, great charts, and yes, I agree! Best charts since 2010... The caveat remains, that there is still a doubt it will fulfill! I'm not normally a half full dude, but something about this, just don't sit right! I love cold and snow.. My favorite type, and yes the ops are saying what I'm saying is wrong, and I hope I am!!! But I do not buy this. Not yet! I need another 12/24 hours to be convinced!

[blackprince]

I am greatly bewildered by some picking apart various GFS ensembles this evening... As far as I can see, these are the only thing that is not pointing towards a possibly very protracted cold and snowy spell...

ECM, its ensembles, the ECM 32 dayer, MOGREPS (according to social media), UKMO, GFS, the Chinese, Indian and Australian models are all pointing to this.

To then show the control run from the gfs in 8 days time as showing south westerlies just strikes me as daft...

This cold spell is not nailed on, and whilst I understand people's concerns, in my 9 years of being on Netweather, these are possibly the best charts I have seen (at least since 2010!) and the snow could be here within 72 hours!

Well said GP I have been a watcher for a few years and have never seen so many sources backing each other up,I can understand the pessimistic posts by those who endured the last swift change but as previous knowlegible posters have said this is a totally different synoptic set up relying on different factors some of which seem to be almost in place.

[fergieweather]

Hi all. Much though I'd love to precis the detailed weekend-Monday analysis just in from Exeter, I can't: it's complex, would take ages and much is commercially sensitive anyway.

However: change of type confidence is, of course, now high but with Shannon entropy still at near record levels, elements of confidence are low. Track of low into weekend has good support however; indeed some adjustments made by Exeter to their GM to align somewhat more alongside EC and GFS. So, in that respect, we are happier with growing continuity on the broad weekend story.However, note WBFL remains widely at 600m+ Sat daytime: heavy rain for most in S, SW etc albeit northern extent uncertain. Either way, signal is strongest as a rain issue Sat (heaviest since Xmas period). But on Sunday, sub-200m WBFL is across whole country; wintry flavour on rear edge of occlusion as it retreats S and profiles suggesting light snow showers in eastern areas (especially) thereafter, even from limited cloud depth. But at this juncture, the key message is how the GFS widespread S snow signal on Saturday is NOT supported in UKMO analysis, versus the very wet potential: so as others have said on forum, don't ever take raw GFS ppn type fields literally at this range!!

By late Sun into Mon, next uncertainty develops into W/NW and confidence extremely low by that juncture.

[bradymk]

Wow, for anyone new, it really doesn't get any better than this for the UK. What we are seeing is great synoptics for cold and snow in latest charts. Was so shocked when the ECM and its ensembles flipped to the GFS outcome earlier, not many times you see that either. I would not worry too much about the GFS ensembles at the moment as other have said, this may be a resolution issue and if the op consistency continues, these will fall into line. I urge no one to get too too excited yet (although it is hard not to) and don't worry if the 00z's aren't quite as good as tonight because they really can't get much better atm. If we still have agreement like this at this time tomorrow evening then I will start to get excited for a potentially long cold and snowy period for most.

Edited January 8, 2013 by bradythemole

[Panayiotis]

I dont see whats wrong with these ensembles, they're amazing for my area, with after the initial cold snap, the temp mean rises then drops to an average of -3C uppers which by my standards are good, however the weekend cold snap is still being changed so looking too far out, is not really recommended.

Edited January 8, 2013 by Panayiotis

[Stormyking]

First time I have posted in a very long time, but I just had to come back!

I dont want to get to carried away yet, because I know anything could happen, but these are basically some of the best model runs, if not the best I have ever seen, just fingers crossed it pulls off!

[rory o gorman]

Ok time to post here, lurking long enough .

There is solid agreement that the first low will undercut from all main models and ens. so high chance of snow for many in the medium term.

As for the gfs Ensembles, a large scatter is to be expected after the 16th as the recent SSW is just registering in the output in the last 2 days.

Given how forecasts and solutions regrading slight changes in data/input come about, this is totally normal with such a abnormal synoptic solutions being revealed in the higher res op currently.

The ukmos and ecmwf are on board with cut off heights to the north.This has a great good chance of verifying into something sustained hold tight guys .

[Great Plum]

Agree GP, but Blighty being Blighty we have to remain wary. Roll on th 00z, I think I'll set my alarm for this run, enthralling stuff regardless of the outcome.

Oh yes, I'm still wary but it is starting to look good...

Interesting that the control was pretty much a mild outlier in the mid term...

It must be Shannon and her entropy...

[chris55]

Weekend looks cold and potentially snowy, tonight is the first time we have cross model agreement up to that point.

Thereafter, and highlighted by the GFS ensembles things are by no means nailed on and although we have cross model support for a continuation of the cold tonight (generally speaking) with the uncertainty offered by the models in recent days this period is still open to change, one evening of brilliant runs across the board doesn't guarantee anything at day 6 onwards. The milder GEFS mirrors what ECM was showing on it's last two runs.

We will need to wait for a few more runs yet to firm up on next week, but in the meant time the weekend looks potentially great.

[Southern Storm]

Hi all. Much though I'd love to precis the detailed weekend-Monday analysis just in from Exeter, I can't: it's complex, would take ages and much is commercially sensitive anyway.

However: change of type confidence is, of course, now high but with Shannon entropy still at near record levels, elements of confidence are low. Track of low into weekend has good support however; indeed some adjustments made by Exeter to their GM to align somewhat more alongside EC and GFS. So, in that respect, we are happier with growing continuity on the broad weekend story.However, note WBFL remains widely at 600m+ Sat daytime: heavy rain for most in S, SW etc albeit northern extent uncertain. Either way, signal is strongest as a rain issue Sat (heaviest since Xmas period). But on Sunday, sub-200m WBFL is across whole country; wintry flavour on rear edge of occlusion as it retreats S and profiles suggesting light snow showers in eastern areas (especially) thereafter, even from limited cloud depth. But at this juncture, the key message is how the GFS widespread S snow signal on Saturday is NOT supported in UKMO analysis, versus the very wet potential: so as others have said on forum, don't ever take raw GFS ppn type fields literally at this range!!

By late Sun into Mon, next uncertainty develops into W/NW and confidence extremely low by that juncture.

fantastic update Mr F, but the only thing I don't fully agree with is in regard to wide spread snow

The gfs if right, has led the way with this setup so we shouldn't discount it all together.

PS where is west is best these days? I hope he finds the time to come on here sometime as he was

Quite knowledgeable if I'm not mistaken.

Edited January 9, 2013 by thunderman24

[SP1986]

its worth nothing that this type of thing happened in the 2010 spell and to an extent the 2008/9 spell, the ensembles often reverted up and down, and struggled to get it pinned down until they all converged (eventually). Not saying that's what will happen this time, but it's happened before so it can conceivably happen again

[weather eater]

One thing for certain in my 9 years of model watching I’ve never seen a cold spell projected out to 384hrs on the GFS and now we have had 4 or 5 in a row, sometime soon we are surely going to see a poor run, to not do so would be unfeasible.

[PolarWarsaw]

Doesn't sound a particularly good update from the MO regarding the white stuff for Saturday, have to say this period despite looking 'potentially exciting' I'm still going to need until at least Thursdays 12z to take any real confidence in the weekends outputs.

If the UKMO is to be believed, I'd imagine the 2 big GFS runs tommorrow will lose snow chances for Saturday.

[bradymk]

Hi all. Much though I'd love to precis the detailed weekend-Monday analysis just in from Exeter, I can't: it's complex, would take ages and much is commercially sensitive anyway.

However: change of type confidence is, of course, now high but with Shannon entropy still at near record levels, elements of confidence are low. Track of low into weekend has good support however; indeed some adjustments made by Exeter to their GM to align somewhat more alongside EC and GFS. So, in that respect, we are happier with growing continuity on the broad weekend story.However, note WBFL remains widely at 600m+ Sat daytime: heavy rain for most in S, SW etc albeit northern extent uncertain. Either way, signal is strongest as a rain issue Sat (heaviest since Xmas period). But on Sunday, sub-200m WBFL is across whole country; wintry flavour on rear edge of occlusion as it retreats S and profiles suggesting light snow showers in eastern areas (especially) thereafter, even from limited cloud depth. But at this juncture, the key message is how the GFS widespread S snow signal on Saturday is NOT supported in UKMO analysis, versus the very wet potential: so as others have said on forum, don't ever take raw GFS ppn type fields literally at this range!!

By late Sun into Mon, next uncertainty develops into W/NW and confidence extremely low by that juncture.

Thanks for the update Ian, much appreciated as always. Just out of interest, any update or information further afield into MR time period? Thanks

[SE Blizzards]

For what it's worth...

I think that GEFS control is having it's 'wobble' just like the ECM had yesterday and earlier today!

Would expect it to change to colder outlook tomorrow.

Have to say that the GFS has been consistent all the way through this, and if this cold weather does arrive then i will most certainly be raising a glass to it!

Great days model watching. Let's all hope for more of the same tomorrow

Edited January 9, 2013 by SE Blizzards