Model Output Discussion 4th Dec.2013-12z onwards.

[phil nw.]

Yes i could see where Steve and Nick were coming from wrt possible Scandinavian ridging.That split in the pv was a window for further development north of Finland but the vortex is too strong to the west and overcomes the ridge quite quickly.

 

One of the first signs of a developing Scandinavia block will be to our west out in the Atlantic.If we see the trough out there disrupting energy south instead of east then that's an indication of the jet stalling and splitting.

 

We can see something like this at T240 on the ECM

http://www.meteociel.fr/modeles/ecmwf/runs/2013121012/ECH1-240.GIF?10-0

 

the problem there though is the trough is already well into the UK in this instance but we can see the resistance of the the modeled block to the east stalling the Atlantic.

Edited December 10, 2013 by phil nw.

[gottolovethisweather]

I think we ought to play another game in here, see how long a forum user can post without mentioning the word MILD or COLD in their posts. I've already ruled myself out and besides, I'm usually only here lurking in the background but of late, I have attempted to add my tuppence to the ongoing debates. So here goes my analysis of pretty much all of today's afternoon NWP output and I will most likely use those aforementioned words again.

 

Whilst it may have been reasonably mild today,   in fact well above especially for parts of Scotland and perhaps Ireland (5c to 8c Temp range considered average for those regions at this time of year), this general theme is largely being removed from all outputs.

 

By the 12th into the 13th December, as anticipated by me a week ago, a change to a stronger Jet dominated active weather regime will have begun to impact  the far North and Northwest of Britain and perhaps with it a lot more rain.   Temperatures still up above average but several degrees down on todays with in this region. Further South and away from the above region, things could get milder still, dependant on sunshine levels and maybe a 11c or 12c isn't out of the realms of possibility. Where isolated fog and low cloud continues to plague prone areas, it will feel far from mild, potentially cold  and maybe average at best. (7c to 9c more usual down South).

 

Come the 14th December (t+96 currently) and thereafter into the unreliable (which is can best be judged by studying where scatter begins on your favoured ensembles runs) all current NWP outputs favour more average Temperatures. These conditions along with bands of rainfall are increasingly showing up of late with a higher percentage favouring colder PM interludes than those from warmer TM airmasses. All precipitation events suggest rain but giving timing nuances snow may become increasingly apparent as time goes by, those favoured by elevation more pleased with this and we'd best forget those of us in low lying areas away from most of England. By the 17th December (t+168 currently), a transient ridge of HP is attempting to return to our shores once again on some outputs, at least out to our SW approaches, but there is not a strong signal for this to happen just now so I personally won' be buying this yet.

 

That for me is broadly speaking the next seven days covered and hopefully by the early part of next week will see if those PM incursions can continue to get a look in.

Edited December 10, 2013 by gottolovethisweather

[nick sussex]

I think we can see the general evolution is well agreed on in terms of events over the UK however IMO there is a possible tipping point in the pattern which means we need to pay attention to the earlier timeframe.

 

The key really is how much of a dig south we can see in this troughing, this effects how much energy spills towards the Svalbard region, because of the overall trend we need the pattern corrected west, in terms of the amplitude of that troughing this is effected by the eastern seaboard of the USA, the ECM T240hrs is really a very common easterly pre-cursor if the pattern is further west because the shortwave runs into the base of the trough, this causes the lower heights to pull away north/nw, energy splits under the block if the high to the east is sufficiently north.

 

Our Xmas miracle needs more amplification and essentially a westwards correction, impossible some might say, we'll see we're not talking of some massive change but a couple more degress of amplification at the key timeframes. The realist in me says the troughing will get too far east and won't dig sufficiently south, Santa says maybe we might get lucky.

 

Which brings me to tonights festive tune from Mr Michael, lets dream and hope for the Net Weather Xmas miracle!

 

http://www.youtube.com/watch?v=l-xzyD00_fI

 

Simply one of the greatest Xmas tunes IMO!

Edited December 10, 2013 by nick sussex

[Hotspur62]

ECM shows a glimmer  of hope for coldies but think we have to be realistic and say it is very unlikely that cold will develop this side of Christmas .tbh been quite nice that we have dried up over last 2 and half weeks down here in SE after relentless rains since end of September.Still think Jan and Feb will bring joy to vast majority on this forum and look forward when snows come that this place will go into usual meltdown!!

[SMU]

The CFS isn't to bad tonight- very UKMO at 144

 

NOTE the 258 chart- just how little atlantic ridging we need for a full blown scandi high just 2 days later

 

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=174&mode=0&carte=1&run=10

S

[Gibby]

Good evening folks. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday December 10th 2013.

 

All models show a Southerly flow over the UK which is very slack across the South with clearer skies allowing a colder night tonight across the South and SE with mist and fog forming in places later tonight and becoming dense in places and slow to clear tomorrow. However, in the days that follow the weatherbecomes more breezy as troughs push in from the West by Friday with some rain at times. Then over the weekend a NW/SE split looks likely with mild weather for all. The North and West will be at risk of some rain at times in a brisk and locally strong SW wind. In The SE though rather cloudy weather will deliver just small amounts of drizzly rain at times if any.

 

GFS then shows a sustained period of SW winds and changeable weather with rain at times with some slightly colder and brighter conditions before SW winds return mild and wet weather in association with the next depression.

 

UKMO shows a trough crossing East on Monday with rain spreading East across the UK through the day followed by drier and brighter or clearer conditions in the West later.

 

GEM also shows a brisk SW winds with a mix of cloudy and damp conditions with rain at times, heaviest in the NW with drier and slightly brighter conditions where the SE sees the most prolonged drier periods with mild conditions prevailing for all.

 

NAVGEM keeps the SE largely dry and bright while places to the NW sees much stronger winds and rain at times in overall mild conditions.

 

ECM shows more unsettled conditions for all of the UK next week with most places seeing some rain at times with strong winds for some. The North would see the most rain though many Southern areas will not see a great deal with some drier spells at times. Temperatures are shown to remain close to average at worst over the period.

 

The GFS Ensembles show little or no sign of anything remarkably cold in the upcoming period covered by the runs which in the case of GFS takes us over Christmas. Instead uppers look like returning towards average values as the more mobile and unsettled weather takes hold.

 

The Jet Stream currently to the NW of Britain continues it's trend to shuffle SE to lies SW to NE across the UK as next week progresses.

 

In Summary there is little change in the overall patterns tonight. As a result there is little to say that hasn't been said already which in a nutshell means the trend towards unsettled and reasonably mild weather continues with little sign of any wintry weather this side of Christmas.

[Barry12]

ECM shows a glimmer  of hope for coldies but think we have to be realistic and say it is very unlikely that cold will develop this side of Christmas .tbh been quite nice that we have dried up over last 2 and half weeks down here in SE after relentless rains since end of September.Still think Jan and Feb will bring joy to vast majority on this forum and look forward when snows come that this place will go into usual meltdown!!

 

Why? a lot change in the UK in 15 days, models could be looking completely different in 10 days.

[cooling climate]

The key is the heights to the northeast without these nothing will change.

the global CDAS 50-hpa temp anomaly chart qives good reason to be a

little on the optimistic side.

[Barry12]

The key is the heights to the northeast without these nothing will change.

the global CDAS 50-hpa temp anomaly chart qives good reason to be a

little on the optimistic side.

temp50anim today.gif

 

I thought you'd written the next 2 months off?

 

'At this point I would say that if the strat charts are looking the same in

another 3 weeks then you virtually right off January as well.'

Edited December 10, 2013 by Barry95

[Ali1977]

Any updates from Ian For today ref long term models that only the Meto get to see ?

[nick sussex]

Any updates from Ian For today ref long term models that only the Meto get to see ?

Yes bitterly cold with snow over the Xmas period but apparently the UKMO staff have shares in SledgesRUs and want to pick a good time to release this news! In reality no we haven't heard anything yet from Ian! We'll see over the next few days whether we can squeeze a bit more interest in terms of the Xmas period.

 

The outlook if you go by my horror rating has improved slightly, I'm hoping the ECM ensembles might show a bit more interest than this mornings.

Edited December 10, 2013 by nick sussex

[Hotspur62]

Why? a lot change in the UK in 15 days, models could be looking completely different in 10 days.

Agree,they could change but all I am saying is that the probability is there wont be significant change by looking at models and other tools(i.e.strenghth of PV).I hope we have a reverse of this time last year when Beast from the East didn't happen. Maybe this year the latest CFS will be right just in time for Chrimbo.!!As Hot Chocolate sung"I believe in Miracles"!! 

[MattH]

Any updates from Ian For today ref long term models that only the Meto get to see ?

Won't speak for Ian but from what I've seen and analysed there's some real wishful thinking going on in here. Outcome seems to be a W or SW'ly type for the foreseeable. Scandinavian highs and the likes are certainly an unlikely solution at the moment. M.

[legritter]

Still plenty to cheer about tonight ,and looking at the last  frames of ECM a couple of adjustments could go in our favour .but its oh oh oh so painfull ,we know there are possibilitys still up for grabs in the outlook but we need to see it in front of us ,perhaps it will show itself over the coming days .THe last couple of runs of GFS have not been so good as last nights Tease at the end ,so will it throw us some more cheer later .Things starting to change a bit in the Arctic regions and close enough for  us to be able to benefit  some ..so at this early stage of this winter Plenty going on, certainly boring for some But a balancing act for mother nature ,there could be surprises Galore ,so dont give up on the Hunt For Cold .PS i saw a big flock of Gulls today ,flying in an anticlockwise direction ,any suggestions .please keep it clean .

[Ali1977]

Cheers Matt/Nick, As mentioned above I guess people want to see the reverse of the beast of the east that never happened...

I wonder if there were signs that it might disappear off the radar like it did !!!

[nick sussex]

Won't speak for Ian but from what I've seen and analysed there's some real wishful thinking going on in here. Outcome seems to be a W or SW'ly type for the foreseeable. Scandinavian highs and the likes are certainly an unlikely solution at the moment.M.

I don't think its wishful thinking, show anyone at the UKMO the ECM 240hrs output and ask them how that could develop if the pattern was a bit more amplified and further west.

 

Given what the outputs were showing a few days back its slightly less Prozac inducing, I agree if you go with the form horse then Santa doesn't exist but we could spend hours discussing variations on mild mush, which will just send everyone to sleep in here. When you say unlikely solution is that unlikely in the Grand National 150/1 shot winning many years ago or just unlikely as in ET is about to land in the Buckingham Palace gardens! ? lol

[tight isobar]

Yes N S the regards of upstream required (are) of major factor.with pv strength atm. As regarding Scandinavia settlement (HP), is as far from being otherwise I have seen!. Ie could be something of instantaneous output flip!! I'm fully eyed atm. There's to my eye something ready for breakidge!!!!

[Captain Shortwave]

I don't think its wishful thinking, show anyone at the UKMO the ECM 240hrs output and ask them how that could develop if the pattern was a bit more amplified and further west.

 

Given what the outputs were showing a few days back its slightly less Prozac inducing, I agree if you go with the form horse then Santa doesn't exist but we could spend hours discussing variations on mild mush, which will just send everyone to sleep in here. When you say unlikely solution is that unlikely in the Grand National 150/1 shot winning many years ago or just unlikely as in ET is about to land in the Buckingham Palace gardens! ? lol

Given how the ECM has performed though, I wouldn't be surprised to see a potential Scandi high get reduced to a Euro high and south/south westerly winds in future outputs. My expectations are very low at this juncture.

Edited December 10, 2013 by Captain shortwave

[gottolovethisweather]

Further to my posting from earlier re: the ensembles, check the undeniable (for me at least) trend afforded by these GEFS 12z suites.

 

 

 

Some progressively colder t850s right there showing up for Aberdeenshire, whereas a week ago the Berkshire t850s showed the following. Note: the extreme drop off in scatter on the chart below concerning the ever-consistent date of Friday the 13th December  which illustrated things were to start livening up out in the Atlantic at t+168 hours.

 

 

They now indicate the following which is definitely showing a trend towards nearer average Temperatures by way of t850s and hopefully more Air Frosts in quieter periods (only one IMBY this meteorological Winter on the 2nd December thus far).

 

 

What is perhaps more striking however, is where FI seemingly begins, for instance you could potentially say it begins as early as the 13th or 14th December  , With this uncertainty in mind you can see why the more professional forecasters among us aren't quite buying into my perceived colder trend just yet! I certainly respect their viewpoints as I will bow to their superior knowledge and for me that is the only way I continue to learn, i.e by listening to them.

Edited December 10, 2013 by gottolovethisweather

[Andy Bown]

Any updates from Ian For today ref long term models that only the Meto get to see ?

Ian practically wrote off chances of a white Christmas for the BBC West region on this evening's forecast, while stating that a change to unsettled conditions with wind and rain were very likely from the end of this week through until Christmas.

[Ali1977]

Ian can only go off the charts I guess, as anyone can and should. It's still only early in terms of getting a very cold spell anyway, there is plenty of time after Xmas to have proper cold.

[bluearmy]

I don't think its wishful thinking, show anyone at the UKMO the ECM 240hrs output and ask them how that could develop if the pattern was a bit more amplified and further west. 

Dont suppose they would bother with a day 10 chart without ens support. There really isnt any reason to take interest in the current fi ecm solutions EXCEPT that for the next 10 days and possibly beyond, the scandi ridge remains strong in the fi ens. each gefs suite has a group of quite amplified solutions which is quite surprising given the situation at day 7. The favourite is not a scandi block with undercutting (as opposed to a ridge/sceuro block) but you just wouldnt be surprised to see that WAA fire up if the jet eases off for a short period.

[UV-RAY]

Won't speak for Ian but from what I've seen and analysed there's some real wishful thinking going on in here. Outcome seems to be a W or SW'ly type for the foreseeable. Scandinavian highs and the likes are certainly an unlikely solution at the moment.M.

With all due respect Matt, it wasn't all that long ago when you was talking about height rises to our NE. So the info you have at your disposal can and does change quite quickly.

[SMU]

A bit controversial post to Gotta.

 

The pro's are no better at creating a mid to long term forecast than the part timers on here - All people are doing is reading what the consensus model shows. They are not forecasts, they are data interpretation & statistical probabilities based on information.

I appreciate this is VERY broadbrush, but for all intensive purposes its not that hard- Theres plenty on here that could ( &do) do that day in day out- Gibby does for instance.

 

Pro forecasters will earn there money & short range forecasts up to 96 hours- where the ability to draw / create fax charts which show frontal zones etc etc becomes superior to the weekend hobbyist- of course its probably a lot easier these days to present a forecast V Pre computer era- however its still a high level science..

 

If you look at the information that's available AFTER the medium term you have

ECM, UKMO4?, Decider models & a few other bits & bobs -

 

Lets say for arguments sake we are 12 days away from a Scandi high & a strong easterly- I would 100% GUARENTEE that even at day 12 the consensus would be against that outcome as the model bias will always overrun the westerly pattern & flatten the blocking pattern-

 

How many times have we seen an Easterly 'appear' from a Scandi high where the high suddenly appears to 'raise' up as T-0 approaches- its because the models are seeing a slower jet & greater amplification.

The GFS & ECM ensemble mean will never pick up a 'ridge' as fast as the operational as the resolution isn't a great.

 

Where the forecasters will be wrong then is clearly when the models are wrong & or the ensemble suites are wrong, so in the MEANs forecasting the height anomaly at day 8-10 is fairly straight forwards-

However whats hard is to forecast when the means are wrong- be it to fast/ to slow etc-

 

I try to do this & yes I don't always call it right-  Look at the call for this week- Scandi heights YES- Scandi High- NO- so longwave pattern correct, shortwave pattern NO.

 

Also, this isn't a dig @ Matt but whatever method you use - you live by the sword & die by the sword- the ECM DET 32 I would bet my house on the next update will show a lot of scandi heights, but not many will go onto a full blown Easterly.

However its to early to dismiss it & way to early to say its wishful thinking-  that's the SAFE bet.

 

What I like at least with Ian is his wording & breakdown does well to cover the plausible outcomes- but of course going with the favoured ensemble option....

 

Well luckily enough we are not bound by any contracts to anyone- just putting our own spin on it. -  IF we can get to a position where we can forecast an outcome which verifies better than the smoothed ensembles this will be better than just brush stroking the canvas with the 500 anomalies. Doing this will take time but Id rather do that than just read the model script as many do on here- pro & hobbyist alike.........

 

S

 

A PS- whenever there are Scandi heights the UK is nearly always on the cusp- right at the end of line as it were- That means small adjustments poleward of the high will often have huge effects on the temps observed over the UK- SW wind 15c SE Wind 3c -

The ECM tonight @ 192 wouldn't take much to show a very cold surface feed......... 

Edited December 10, 2013 by Steve Murr

[ANYWEATHER]

I don't see a lot of change from last nights models, with a strong influence from the Atlantic and with some brief ridges especially for southern Britain. Both ecm and gfs ,even at the unreliable timeframe[T+168 and T+240] show the usual default pattern for the uk at this time of year. No Northern blocking predicted in the near future. So with low pressure over Greenland and high pressure over the Azores, you will get this scenario. Not to say that we wont get some colder incursions from the NorthWest at times given the synoptics and some places will briefly see some snow, especially over high ground, and as for Christmas still a long way off, but the trend from the models wont be a White Christmas, but a Stormy and wet one!!