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

[gaia rules]

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.

I agree that this is a really good update. Like Thunderman I would be very nervous working at the Met Office regarding the possible snow this Saturday! If the rain is very heavy and there is a significant cold undercut surely that boundary between rain and snow is still totally uncertain and could be anywhere!

Edited January 9, 2013 by gaia rules

[weather eater]

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

I suspect you are right it would be no surprise, Personally I never look at them or worry about them, much better to use the days operational’s as a guide. People forget they are a guide for the operational not alternatives, if they were what would be the point of an operational run.

[bradymk]

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.

. Needs to be noted that GFS precip charts are only a rough guide because of the low resolution, UKMO have access to high resolution precipitation models which are far more accurate. Always take GFS hatched snow charts as rough guides only. For the public, NAE and NMM are the best for time period up to 48 hours and late Thursday and Friday will be the first signs on these. Edited January 9, 2013 by bradythemole

[Bobby]

Remember, Ian F said that uncertainty is at all time record levels so should we be surprised at the 18z ensembles? It would be rather strange to have total agreement with record uncertainty wouldn't it? Nothing should be taken for granted at the moment me thinks.

If the big models and ECM ensembles are on board by tomorrow 12z then we can start feeling more confident.

[SP1986]

I suspect you are right it would be no surprise, Personally I never look at them or worry about them, much better to use the days operational’s as a guide. People forget they are a guide for the operational not alternatives, if they were what would be the point of an operational run.

Given models are experimental it makes sense for there to be a range of outputs, and they are useful to a certain extent. They do have their limitations, but we shouldn't discount the control run. The other thing I remember about the 2010 runs is that the ensembles basically led the way when they got their act together, despite the operational and control often wildly diverging.

If we run on that basis, it is feesible, the ensembles could well be the key to this.. but there is clearly too much disagreement within the reliable timeframe at the moment to be sure of anything.

As it stands at the moment, it's probably best as you suggest, sticking with the operational, until things become clearer.

Edited January 9, 2013 by SP1986

[The Eagle]

If we are to have any real confidence regarding Sunday onward this sort of ensemble has to end realistically.

It

[The Eagle]

The met office over here have just updated their forecast on the back of the 12z output - stunning reversal from earlier actually. This for Ireland obviously so extrapolate from that.

The weekend looks like it will be chilly, the lowest values, probably in the low single figures, will be in the East with Easterly or Northeasterly breezes. There will be a good deal of dry weather with some wintry sunshine but some showers also, these turning increasingly to sleet and snow especially on Sunday. Nights will be frosty with fog and ice.

At the moment Sunday night and the early days of next week brings the threat of more significant snow to places and it will feel very cold with the winds strengthening.

http://www.met.ie/forecasts/

Edited January 9, 2013 by The Eagle

[CanadaAl]

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.

But the thing is, the likelyhood of the GFS converging towards the UKMO outlook would be very slim i would of thought. Usually it's the other way around. It just reminds me of last month when ECMWF and GFS went with turning milder but the UKMO held on. And of course, UKMO ended up going the way of GFS and ECMWF. Obviously in this case milder air is easier to predict but even so, with the cross-model agreement. I do think UKMO might side more towards GFS' and ECMWF way of thinking, after all, UKMO does base itself around ECMWF. An interesting time ahead!

[snowmadchrisuk]

Even the GFS has it as rain Saturday for the S/SW , Northward extent will decide if anybody gets any Snow , South Mids Northwards would be my guess if it makes that far ... Also timing will make a big difference , It may be possible that the Colder air can under cut the Milder air wrapped round the Low.

[bobbydog]

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.

i wouldnt worry too much about detail, at this range i would go with the professionals. as has been said, the GFS snow charts are only a rough guide and i wouldnt be surprised if we only see mostly rain on saturday. however, that could easily change for the better and confidence seems good from then on for snow. that said, the GFS did bring the snow forward a day so who knows what will happen! forecasting snow is very difficult and can often be underestimated. i remember 2010 when the forecast for me said about 3cm.we ended up under a thames streamer and a foot of snow!

lamp-posts at the ready!

[124alex]

Even the GFS has it as rain Saturday for the S/SW , Northward extent will decide if anybody gets any Snow , South Mids Northwards would be my guess if it makes that far ... Also timing will make a big difference , It may be possible that the Colder air can under cut the Milder air wrapped round the Low.

fingers crossed for our region still a few days to go yet.

[bradymk]

Hope Ian F doesn't mind me copying this from the SW thread, some info on weekend and I wonder what he means in his last sentence?

Don't despair! Saturday only the transitional day! And anyway: much can and will change on ppn detail. Wintry flavour will v much depend on strength of undercut phased with frontal advance and then retreat Sunday. And looking further into MR... well, it has potential to be truly dire across the UK.

[snowmadchrisuk]

fingers crossed for our region still a few days to go yet.

fingers crossed x x although I will be keeping an eye on the 850's rather than the PPN , one thing about living in Somerset , is that you never miss out on anything that comes off the Atlantic ... Never stops raining in Weston.

[rory o gorman]

The met office over here have just updated their forecast on the back of the 12z output - stunning reversal from earlier actually. This for Ireland obviously so extrapolate from that.

http://www.met.ie/forecasts/

not surprising at all as the Irish met go strictly by the book off the ecm OP.

[pyrotech]

Yes surprises can happen, especially if we get a layer of dry air that would allow some evaporative cooling, i would expect Meto to have taken this into account thou.

Saturday looks interesting to me as the band moves thru, looks like a possible North of the M4 hill snow event, ( not good for me they built the dam M4 a few miles to far North) Seems Meto do not agree. Upper air is borderline and if Low is slightly further North then unlikely. But i suggest what Meto see now is most likely event with slight upgrade or downgrade as we move forwards.

However if the GFS and ECM have that right, which Meto think they do in general, then there is huge hope that FI is also correct somewhat.

It stands to reason that if that low was completely out of place, that all the run after would be wrong, but it seems that far the consistancy is now getting agreed, just the fine details are being debated by various models.

[fergieweather]

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

Yes. They run with cold story into foreseeable: low prob significant cold & low prob significant snow, but major uncertainty. Key initial problem post-Sun arises from significant difference in MOGREPS handling of low that EC/GFS prog to affect W areas with snow. MOGREPS runs it more easterly and N of UK, thereby maintaining higher pressure and drier weather. EC solution favoured for now but with caveats. Thereafter, largely dry, cold week follows with UKMO noting problematic milder members in ensembles that can't be wholly discounted. Highest probs of rain / milder injections into W / SW, thus with attendant if perhaps transient snow threat, but UKMO acknowledge more widespread threat of severe conditions should some ENS solutions become reality. EDIT risk of heaviest snow is considered largely for eastern areas throughout 6-15d period but also periodically further W.

Edited January 9, 2013 by fergieweather

[Southern Storm]

Moving away from gfs mania for a second, did anyone watch stargazing live tonight?

The reason I ask this is because they performed a demonstration with a charged rod and some water

And I was amazed to find how much effect charged particles have on diverting the flow of water

This got me thinking, the atmosphere is composed mostly of water vapour, so would it be possible to Modle earth bound coronal mass ejections and the possible diversion of large scale weather systems?

Sorry if this is not the place to post this, so please move if needed.

Edited January 9, 2013 by thunderman24

[Buzzit]

Yes. They run with cold story into foreseeable: low prob significant cold & low prob significant snow, but major uncertainty. Key initial problem post-Sun arises from significant difference in MOGREPS handling of low that EC/GFS prog to affect W areas with snow. MOGREPS runs it more easterly and N of UK, thereby maintaining high pressure and dry weather. EC solution favoured for now but with caveats. Thereafter, largely dry, cold week follows with UKMO noting problematic milder members in ensembles that can't be wholly discounted. Highest probs of rain / milder injections into W / SW, thus with attendant if perhaps transient snow threat, but UKMO acknowledge more widespread threat of severe conditions should some ENS solutions become reality. EDIT risk of heaviest snow is considered largely for eastern areas throughout 6-15d period but also periodically further W.

Ian : I have to say once again (I'm sure on behalf of many of us) that your posts on Netweather have not just been appreciated, but that having you post here has made the overall Netweather experience just that bit better - so thank you once again.

[John Cox]

The irish met office have changed their forecast from am 8th Jan:

"there is a possibility of cloudy, milder weather again moving in from the Atlantic during Sunday and Sunday night bringing temperatures back up to between 8 and 12 degrees for next week with some wet and windy spells likely. "

to:

"At the moment Sunday night and the early days of next week brings the threat of more significant snow to places and it will feel very cold with the winds strengthening"

This is very encouraging

Just noticed your similar post "The Eagle" . Yes they have changed it in line with the ECM coming on board.

Edited January 9, 2013 by John Cox

[Bobby]

Ian : I have to say once again (I'm sure on behalf of many of us) that your posts on Netweather have not just been appreciated, but that having you post here has made the overall Netweather experience just that bit better - so thank you once again.

Yes it's very welcome to have the input of a pro as well information about non-public models, Ian doesn't have to come here after all and tell us this stuff does he, but glad he does for sure.

[Bonjangle]

Another PETE TONG -- always happens .

Misfit's all the time , and after great charts like that ..... aving a Giraffe .

Its gonna get cold as we all know and as for that white stuff coming , yep i got it here as i been scratching my hairy head all day and my shoulders are covered in Dandruff , only white im gonna see .

waiting for 0z , thats like 2 hours away .

Kool ill wait up and see .....yeh ...

[Rob K]

Yes. They run with cold story into foreseeable: low prob significant cold & low prob significant snow, but major uncertainty. Key initial problem post-Sun arises from significant difference in MOGREPS handling of low that EC/GFS prog to affect W areas with snow. MOGREPS runs it more easterly and N of UK, thereby maintaining higher pressure and drier weather. EC solution favoured for now but with caveats. Thereafter, largely dry, cold week follows with UKMO noting problematic milder members in ensembles that can't be wholly discounted. Highest probs of rain / milder injections into W / SW, thus with attendant if perhaps transient snow threat, but UKMO acknowledge more widespread threat of severe conditions should some ENS solutions become reality. EDIT risk of heaviest snow is considered largely for eastern areas throughout 6-15d period but also periodically further W.

Very interesting stuff Ian, thanks,. I've just watched your forecast from earlier on here http://news.bbc.co.uk/weather/hi/news/newsid_7760000/7760862.stm - very good clear explanation of what's happening (or might be happening!)

Wish we had more of that rather than the dizzy blondes (of both sexes) moaning about it being bitterly cold if it drops below 8C...

[Timmytour]

I like Chinese

I like Chinese

It churns it out by slow degrees

But it's very friendly and it gives us a freeze

Another vote of thanks to Chart Viewer

[SnowObsessor90]

So here we are yet again at the point of crossroads, fingers crossed that this'll be third time lucky and not yet another implosion.

[Cheshire Freeze]

So here we are yet again at the point of crossroads, fingers crossed that this'll be third time lucky and not yet another implosion.

I'm waiting up for the 0z GFS and UKMO......sad I know but hope it's worth it!