Winter Model Discussion - 12/01/13 06z Onwards

[EML Network]

What frustrates me, is that we're always looking 4-5 days ahead.

As soon as any possible snow events get to within 2-3 days away, they start to water down and only a very few get lucky, or it turns out to be a complete non event.

Looking through the various GFS runs, Precipitation charts, uppers etc...there's hardly any agreement what so ever even as early as + 96.

I think the next 24 hours models are all worth taking with the smallest pinch of salt, everything is changing hour by hour, I have no faith in any of them at this present time.

[Methuselah]

If its likely to come off there will be advanced warnings by the end of Tuesday.

I remember the 1982 blizzard in South Wales, we were warned a week in advance of that one. That's when forecasts seemed more accurate!

Looking at the various charts, it does seem to be an option so the forecasters will be watching closely.

'Seemed' being the operative word.

[Neilsouth]

What frustrates me, is that we're always looking 4-5 days ahead.

Pretty much and it's why I've been pushing on this forum for a separate thread 0 - 48hrs / FI 48HRS+

[ChartViewer]

Yes, it looks like we have lost quite a bit of the convective opportunity for midweek, which has mostly been overlooked in all the (understandable) excitement about the UKMO T120 chart!

Will be interesting to see how the fax charts look when they are issued later.

Convective opportunity.......anything past T6 and anyone is guessing for snow/rain.....lots of snow opportunities maybe? this week to come imho and regional threads will be buzzing.....who knows...but nice and cold anyhow

Edited January 13, 2013 by ChartViewer

[AWD]

Massive scatter on the short ens;

Operational a colder option in the short term, but there is no clear trend at all for next weekend.

[NorthNorfolkWeather]

So, for those that have been saying that there are huge differences between the GFS and UKMO at T144, here are the 500MB charts for GFS, UKMO and ECMWF

First ECM 144

Then GFS 144

Then UKMO 144

They all feature a mega low in the Atlantic, both the ECM and the GFS seem to want to send all the energy over the top of the block and indeed both are 800 to 1000 mile (up to 1600 Km West of where the UKMO has the low in their chart, so something has dramatically affected the UKMO Model to throw that low so far East and undercutting

If we come back to T72, to see if we can start to pick up the evolution of the differences, it looks as though both the ECM and GFS have slightly stronger blocks in 3 days time, but the differences other than that, to my untrained eye, are negligible

ECM T72

GFS T72

UKMO T72

Edited January 13, 2013 by NorthNorfolkWeather

[Buzz]

Still think that UKMO chart is so good for Friday that it won't verify! There seems to be a lot of factors midweek that could change the end of the week's forecast. The low to the SW seems to blow up out of nowhere! Can we realistically expect that level of energy running under the block? Fascinating stuff.

Not really. First remember that the UKMO output from T+72 is in 24 hour increments, not 6 hours like the GFS output.

UKMO 96 hours:

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=96&carte=1021

notice the south easterly 'bulge' to the south west of the UK

UKMO 120 hours:

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=120&carte=1021

which then becomes this.

[goosey007]

If its likely to come off there will be advanced warnings by the end of Tuesday.

I remember the 1982 blizzard in South Wales, we were warned a week in advance of that one. That's when forecasts seemed more accurate!

Looking at the various charts, it does seem to be an option so the forecasters will be watching closely.

Thanks LORD STRATUS' I think theres alot of head scatching going on at the Met office, I for one refuse to get excited about UKMO T+120 far far too many dissapointments. We shall see

[IDO]

Another GFS run, another to forget:

Clear mild outlier after D7. Too progressive with the Atlantic still.

Highlighted by 500pHa ens:

[MR EXTREMES]

So, for those that have been saying that there are huge differences between the GFS and UKMO at T144, here are the 500MB charts for GFS, UKMO and ECMWF

First ECM 144

Then GFS 144

Then UKMO 144

They all feature a mega low in the Atlantic, both the ECM and the GFS seem to want to send all the energy over the top of the block and indeed both are 800 to 1000 mile (up to 1600 Km West of where the UKMO has the low in their chart, so something has dramatically affected the UKMO Model to throw that low so far East and undercutting

If we come back to T72, to see if we can start to pick up the evolution of the differences, it looks as though both the ECM and GFS have slightly stronger blocks in 3 days time, but the differences other than that, to my untrained eye, are negligible

ECM T72

GFS T72

UKMO T72

spot the odd one out id say ecm looks the odd one with a secondry low pressure to the north.

but both ukmo and gfs have it there at t72

Edited January 13, 2013 by model rollercoaster

[Methuselah]

I don't really understand this...surely a lot of the weather conditions we receive rely, primarily, on the upstream conditions along the east coast of the USA? I don't think you can "localise" weather as such, given that it's all interconnected.

I'm not suggesting that I understand it either, wg...But, for what it's worth, if I were the one responsible for the algorithms, I would expect to be (in some subtle way at least and either consciously or unconsciously) basing the algorithms in respect to what I knew best; things about which I know least would, necessarily, receive less attention...

That's really all I'm saying: that all of us are biased towards our own locales??? My statement was not intended to be in any way derogatory...

Edited January 13, 2013 by Rybris Ponce

[bluearmy]

NNW, ecm sends energy under the block - just not as much as it send over it. Gfs also send energy under but again, not as much as ukmo/gem. Lets see if ecm is as bullish about its atlantic jet profile on the 12z. There isnt as much difference between the models as you might think. Its a fine tipping point with the jet energy and the block does very well considering the energy off the atlantic with those northerly arms.

[NorthNorfolkWeather]

spot the odd one out id say ecm looks the odd one with a secondry low pressure to the north.

but both ukmo and gfs have it there at t72

Good spot that, and a really point point. Also interesting point made by Buss, about that Bulge to the South East in the UKMO model at T96

[Timmytour]

Eyes down for the ECM then...drink of choice to hand. (Tea for me!)

Hoping for a sterling run that shows us being pounded with snow....which turns out to be on the money!

[NorthNorfolkWeather]

NNW, ecm sends energy under the block - just not as much as it send over it. Gfs also send energy under but again, not as much as ukmo/gem. Lets see if ecm is as bullish about its atlantic jet profile on the 12z. There isnt as much difference between the models as you might think. Its a fine tipping point with the jet energy and the block does very well considering the energy off the atlantic with those northerly arms.

I'd beg to differ, by the time you are at T240 (I know well into FI so not really worth considering) ECM has us in South westerlies

Edited January 13, 2013 by NorthNorfolkWeather

[ChartViewer]

NNW, ecm sends energy under the block - just not as much as it send over it. Gfs also send energy under but again, not as much as ukmo/gem. Lets see if ecm is as bullish about its atlantic jet profile on the 12z. There isnt as much difference between the models as you might think. Its a fine tipping point with the jet energy and the block does very well considering the energy off the atlantic with those northerly arms.

Agreed ba....really is a fine tipping point.....less energy near iceland and we prolong the block...more energy going west to east and its flatter.....split vortex so more of a bridge to jump ...chios thoughts , im in the more prolonged cold spell camp.......less energy more resistance of the block...at least until 21st....interesting ECM Tonight.......

[Jason M]

Hmm, GFS ensembles at 180 are really rather good. Trend towards scandi heights hanging on. No point looking into low res as I can guess where things will go from that point given the PV set up :-)

Jason

[TEITS]

The last time I saw verification stats in dec 2012 the ukmo was nowhere near the top end, it actually came third! So many are blinded on this forum by false optimism, all they see is the latest charts, then when then they all agree suddenly each one is as good as each other while forgetting the previous updates! The ukmo is an utter travesty of a model in winter days and is always playing catch up

Firstly what on earth has Dec got to do with it, whatever happened in Dec has no bearing whatsoever in the current period. If we look at the LP that is diving S tomorrow it was only a few days ago the GFS realised this whereas the UKMO was rock solid in predicting this.

[Continental Climate]

what really kicked me in the cahoonas was the big downgrade in the midweek easterly on the UKMO im still recovering from it really hope the ECM peps it back up again

[East Herts Snow]

I come to the conclusion that we are both blessed and cursed with having access to so many weather charts and all of their various permutations.

I recall the days when you would have to wait for the next day's chart in the daily newspaper which would give you a basic forecast up to 48 hours. Then along came Teletext and BBC's Ceefax which had regular daily updates presented via very basic weather images (but at the time state of the art technology). It even provided a 7 day long range forecast for all UK cities and World capitals.

This was an enormous leap forward in having a weather predictor at your finger tips and I would be glued to Ceefax during times of cold weather, even up to the late 1990's!

I think all of various weather services provide an excellent service overall and verify the majority of the time up to around 72 hours, which I feel is truly amazing. The weather is chaotic and always subject to change due to a new variable being introduced somewhere in the world at anytime (be it a volcanic eruption, or solar flare etc).

I feel a lot of the thrill in seeking cold and snowy weather is looking at all of the various charts and making your own forecast up and then looking smug when it does, but the majority of the time I fail :-)

I feel we are shaping up for a memorable cold spell, but if it doesn't happen just enjoy the charts that are being thrown up as this is a rare event for many parts of the British Isles.

Edited January 13, 2013 by East Herts Snow

[Stuie]

I think maybe tomorrow regarding snow, Anglia "could" be upgraded with the pool of colder air that the ECM shows.

[TEITS]

what really kicked me in the cahoonas was the big downgrade in the midweek easterly on the UKMO im still recovering from it really hope the ECM peps it back up again

I know what you mean but it could change and its only because of the LP near Iceland.

Could be wrong but I feel the ECM at +72 will have a better, more convective E,ly.

[manutdmatt1986]

I think maybe tomorrow regarding snow, Anglia "could" be upgraded with the pool of colder air that the ECM shows.

If I'm reading it right, the warm sector is only over on the South West on this run (unless it moves further East later on).

Edited January 13, 2013 by manutdmatt1986

[Stuie]

If I'm reading it right, the warm sector is only over on the South West on this run (unless it moves East further later on).

There is no warm sector, even the west is around -4. Anglia looks to me to have -12 uppers! All to play for tomorrow.

ED: Probably -10

Edited January 13, 2013 by StuieW

[ChartViewer]

ECM T72

Edited January 13, 2013 by ChartViewer