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Model Output Discussion - The final stretch to Christmas


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Mean while in the real world away from the MOD... A tragic accident has cost 6 lives in Glasgow. yes this is off topic but a timely reminder of just how unimportant the weather really is in our lives.

There is an enormous lack of respect for other people in this thread at the moment. I suggest that if one doesn't have something to add to the model discussion with a salient chart or pertinent inf

Model uncertainty throwing both operational and ensemble data into discontinuity has proved as rife as was expected a week ago - when AAM flipped to negative tendency along with GWO phasing that was i

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Karlos - you have attached the spread on uppers rather than heights. More difficult to deduce too much on uppers spreads

The height spread on ecm shows a fair cluster going for a deepish depression headed w to e well to our North

 

Dam it, cheers BA, I've removed my post. Will try again tomorrow perhaps...

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Hi TBF

 

Your observations are all valid in my humble opinion.

re track of low and amount of mixing etc, well that is the million dollar question but the general idea that snow to the North and west of the low as it sinks is correct as the warm sector is pushed South ahead and colder uppers filter back in behind on an Easterly flow.

 

You are right about the track the UKMO currently shows, give or take, and yes a storm surge would definitely be a concern.

I think we can expect to hear more about that from Ian Ferguson if things continue along these lines a bit nearer the time.

 

Certainly a very interesting period of weather coming up one way or another.

 

Hi Mucka, RJBW, John Holmes

 

Thank you for replying to my post. I would have thought the path of this low would now be within the realistic timeframe for having a good handle on its likely track? When do you think the depth and track will be considered to be nailed on so that appropriate warnings [if needed] can be given? I understand that the models have been really flip flopping around lately and it was really good to see the BBC showing that there are two possible outcomes for the weekend, but given that one of them, should it pan out would likely see a strong storm surge push down the North sea in conjunction with some very big tides, might it not be an idea for some kind of warning [even if nothing comes of it] to be made? or at what point would they start to issue warnings? This would give people in those flood risk zones who might be travelling away for xmas the option to prepare for the worst. I know I would rather take some kind of preventative / damage limitation measures before going away and it being a false alarm, than to not have that option and come home to my house and belongings damaged and ruined by floods I knew nothing about until it was too late? I have been urging people to pay close attention to the weekends weather r.e the potential risk to flooding, and the majority of responses are quite lackadaisical. Fingers crossed in relation to a surge, the low will weaken or track differently.

 

storm2014_zps30e9752e.jpg

 

The reason for my concern is that during and leading up to last Decembers surge people were taking the eventual warnings with a pinch of salt probably due to having several flood warnings every year and nothing ever coming of them for god knows how many years. During the mornings high tide I was at the coast taking photographs as it was close to breaching and got talking to two wet behind the ears lads from the environment agency who were saying they were going to downgrade the flood alerts for the night time high tide!! I asked them if they were they joking as the gale force onshore wind was going to be holding that tide in preventing it from fully going out and with the winds not set to drop and the evening high tide no smaller it was going to breach 100% and they completely dismissed what I and some of the flood wardens were saying!! I knew it was going to flood and that sandbags would be needed and that most other people wouldn't realise until it was too late ,which is why myself and a load of friends went and bagged up sandbags for the elderly. People / families were walking up to river wall to look at the "higher than normal tide" hand in hand laughing and joking, then seeing it, realising, and literally started running back to put sandbags into their car. 

 

p.s I am trying to find and view the charts from last years surge to draw comparisons, how / where do I do this? thanks 

Edited by TheBigFreeze
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Not sure how we have suddenly got onto the topic of where it's going to snow ??

 

We don't even know the track, orientation, strength of the low yet ?

 

Some people really need to learn from the past and not build themselves us to be let down. 

 

If the low comes off as modeled by the UKMO your looking at Euro home grown cold rather than a long draw from a proper cold source and in my limited experience, that's not really good enough to produce snow at low levels, maybe a little sleet on the hills, but likely rain for most, exception perhaps the usual favored spots in NE England such as Sheffield, Newcastle ,Lincoln down to Cromer.

 

But you'd usually need to have the cold air already in place, to get the dew points low and wet bulb levels down sufficiently for any snow to settle and I can't see that happening. 

 

Still it's nice to see the ECM and UKMO in relative agreement finally and like others have said MUCH better than this time last year, it pattern does look to flatten out a little into FI, the GFS is very bullish abut this in recent runs, if were to move away from that to something more blocked we'd probably start seeing it showing up in today's runs. 

 

In my opinion of course and I'm new to this, so please don't beat me up :-)

 

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Well another day, another dollar (at least for those of us sad enough to be working while everyone else watches telly and feasts on spiced biscuits)

It's a case of take your pick from the models, with the analysis of various members nuanced by their own preference (do they go for an ECM style freeze up or highlight GFS reverting to zonal at T240hrs?)

I would go seasonal with a chance at snow for NE/SE on Sunday but need more info on the low.

More runs needed! :)

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Hi Mucka, RJBW, John Holmes

 

Thank you for replying to my post. I would have thought the path of this low would now be within the realistic timeframe for having a good handle on its likely track? When do you think the depth and track will be considered to be nailed on so that appropriate warnings [if needed] can be given? I understand that the models have been really flip flopping around lately and it was really good to see the BBC showing that there are two possible outcomes for the weekend, but given that one of them, should it pan out would likely see a strong storm surge push down the North sea in conjunction with some very big tides, might it not be an idea for some kind of warning [even if nothing comes of it] to be made? or at what point would they start to issue warnings? This would give people in those flood risk zones who might be travelling away for xmas the option to prepare for the worst. I know I would rather take some kind of preventative / damage limitation measures before going away and it being a false alarm, than to not have that option and come home to my house and belongings damaged and ruined by floods I knew nothing about until it was too late? I have been urging people to pay close attention to the weekends weather r.e the potential risk to flooding, and the majority of responses are quite lackadaisical. Fingers crossed in relation to a surge, the low will weaken or track differently.

 

storm2014_zps30e9752e.jpg

 

The reason for my concern is that during and leading up to last Decembers surge people were taking the eventual warnings with a pinch of salt probably due to having several flood warnings every year and nothing ever coming of them for god knows how many years. During the mornings high tide I was at the coast taking photographs as it was close to breaching and got talking to two wet behind the ears lads from the environment agency who were saying they were going to downgrade the flood alerts for the night time high tide!! I asked them if they were they joking as the gale force onshore wind was going to be holding that tide in preventing it from fully going out and with the winds not set to drop and the evening high tide no smaller it was going to breach 100% and they completely dismissed what I and some of the flood wardens were saying!! I knew it was going to flood and that sandbags would be needed and that most other people wouldn't realise until it was too late ,which is why myself and a load of friends went and bagged up sandbags for the elderly. People / families were walking up to river wall to look at the "higher than normal tide" hand in hand laughing and joking, then seeing it, realising, and literally started running back to put sandbags into their car. 

 

p.s I am trying to find and view the charts from last years surge to draw comparisons, how / where do I do this? thanks 

The weather will do what it will do but dartboard lows have been downgraded, as per usual. So I wouldn't be forecasting acopalypse personally.

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Looking at the models, to me anyway, it seems after the low/potential storm, there is a brief high pressure then back to south westerly's.

It seems to me that a lot of people on here take the uncertainty of the models to mean that the atlantic weather probably wont happen, and use conjecture to fantasize what happens next.

Maybe im wrong, but surely considering this country gets south westerlies the vast majority of the year, this means beyond the low then high pressure this coming weekend, chances are we will back to 'zonal' given that models also show this??

 

Well, uncertainty in the models should actually decrease the chances of a zonal setup. With it being the most common situation, theoretically it should be the easiest to spot. When you have only one model forecasting a certain setup, against all the others, I'd say the chances of that setup coming to fruition are lower. Lower still when you have GFS 'zonal' versus an ECMWF/UKMO agreement on something different. Also bear in mind that the GFS is only low res up to a certain point and it's known for 'defaulting' to the usual once it hits that timescale. 

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I wouldn't rule out there being some kind of easterly setting up near the new year, cfs seems pretty keen to bring in a very cold easterly from the 27th. Deffinatly one to watch.

 

CFS is about as reliable as a flea! GFS I usually look to

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I wouldn't rule out there being some kind of easterly setting up near the new year, cfs seems pretty keen to bring in a very cold easterly from the 27th. Deffinatly one to watch.

 

Not sure where you see this ?

 

06_102_mslp500.png?cb=912

 

06_102_windvector.png?cb=912

 

All the way to 1st. Jan...

 

06_264_mslp500.png?cb=912

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CFS is about as reliable as a flea! GFS I usually look to

I agree but its true to say that the CFS model has suggested an easterly for January for sometime now. It would be great to have a cold January which have been very rare since the 90's

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CFS is about as reliable as a flea! GFS I usually look to

Not bad to pick up trends, let's be honest none of the models are hardly performing well at the moment.

Not sure where you see this ?

 

06_102_mslp500.png?cb=912

 

06_102_windvector.png?cb=912

 

All the way to 1st. Jan...

 

06_264_mslp500.png?cb=912

Big clue when I said cfs not gfs

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Interesting GFS (P), takes the initial low a little further east to the Euros, but the same sort of idea

gfs-0-120.png?6

By day 7 we have this

gfs-0-168.png?6

Starting to get interesting with a cold flow trying to develop from the east/south east.

 

GFS op takes the low into Scandinavia and pushes the westerly flow through the UK with ease.

Edited by Captain shortwave
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If this LP over the weekend gets downgraded anymore it will be nothing but back edge cold to a brief toppler. The op has the LP to our north and diving down the North Sea with maybe some coastal wintry showers:

 

post-14819-0-77081000-1419330263_thumb.p  P: post-14819-0-03299200-1419330319_thumb.p

 

The P is slightly further west and may give some back edge snow to hills but very touch and go. The op at D7 similar to this morning:

 

post-14819-0-79817700-1419330393_thumb.p  P: post-14819-0-95777300-1419330417_thumb.p

 

The new ECM, that is the GFS P manages to be more amplified towards the NE. Thats a bit closer to the reliable than its normal over amping and was a theme this morning so possible interest.

Edited by i'm dreaming of...
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http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

ECMWF 8-10 day 500mb anomaly chart is today indicating an omega block over the UK with low heights over the Med. There is a weaker block also with a  vaguely omega shape in the eastern Pacific. The blocks are less well marked on GFS but nonetheless are indicative, if they verify, of a slowing down of the northern hemisphere circulation perhaps allowing a colder period to evolve over northern Europe.

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If this LP over the weekend gets downgraded anymore it will be nothing but back edge cold to a brief toppler. The op has the LP to our north and diving down the North Sea with maybe some coastal wintry showers:

 

attachicon.gifgfs-0-114.png  P: attachicon.gifgfs-0-114 (1).png

 

The P is slightly further west and may give some back edge snow to hills but very touch and go. The op at D7 similar to this morning:

 

attachicon.gifgfs-0-174.png  P: attachicon.gifgfs-0-174 (1).png

 

The new ECM, that is the P manages to be more amplified towards the NE. Thats a bit closer to the reliable than its normal over amping and was a theme this morning so possible interest.

So now we have the ECM(p) as well?! Shurly shome mistake?  :girl_devil:

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Interesting GFS (P), takes the initial low a little further east to the Euros, but the same sort of idea

gfs-0-120.png?6

By day 7 we have this

gfs-0-168.png?6

Starting to get interesting with a cold flow trying to develop from the east/south east.

 

GFS op takes the low into Scandinavia and pushes the westerly flow through the UK with ease.

 

Yeah the GFS(P) continuing it's trend from the 0Z of moving the low more to the SE (yesterday's 18Z had it going E/NE, today's 0Z seemed to split some E/NE and some SE). The normal GFS is still having none of this new trend from it's younger sibling and is stubbornly continuing to send everything towards Norway.

Edited by Ravelin
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Could the GFS and its naughty sister GFSp be any different? Yet again, GFSp wants to carve out a cold solution,  building a Scandi high by New Year's Eve, whereas the original model goes for a near Bartlett at the same juncture. 

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