Model Output Discussion 1st January 2014-06z onwards.

[Cheshire Freeze]

Looking at the GEFS ensemble mean, there looks to be 2 major players at 180 hrs. There's the strong Greenland/Canadian sector vortex and the old rogue....an Arctic high over on the Siberian side. All I'll say is that with that situation the foundations are well and truly laid. A lowering of heights over Europe & slight relaxation of the jet would all but light the fuse.

 

[Cecil Hogmanay Melchett]

http://www.meteociel.fr/ukmo/runs/2014010212/UN144-21.GIF?02-17

 

 

pretty good UKMO tonight !!

 

GFS party pooper as usual

 

s

Can i ask what you see in UKMO steve?

[bluearmy]

 

Can i ask what you see in UKMO steve?

 you really cant see HD? i made a post this morning re the extended ens and their take on the next fortnight. that the ops had not made the running as yet this season and why now ? well there is a possibility that now could be their time. we have an upcoming scenario where lots of differing parts of the hemispherical patterns are interacting at the same time. with the behaviour of the polar high also crucial to the evolution, its feasible that the higher resolution of the ops is required to pin down the pattern at day 5/6. if the ens are in the wrong place at this timescale, then what they dish out thereafter will also be out of kilter to what may verify. its a small straw to clutch but it does happen from time to time and we are due a bit of luck from a cold perspective.

[R.P. McMurphy]

That was the point of the post, pointing out the wild swings from run to run.

Thanks Nick, just to clarify that was the point of my post, and the 6 hours is usually the next update wait time... 00Z 0330-0445 | 06Z 0930-1045 | 12Z 1530-1645 | 18Z 2130-2245 (GMT)^^ every 6 hours ^^Hence the amount of fluctuation on the charts from one update to another. Would love the 12Z to be right, but just appears quite wild to me.

[johnholmes]

Any idea what the latest verif stats at T+144hrs are Steve, or anyone? From memory wasn't UKMO one of the worst at that range recently?

 

another red herring shed-much of the time, it is second to ECMWF with GFS often, not always, but often 3rd as the current stats show

[Cecil Hogmanay Melchett]

   you really cant see HD? i made a post this morning re the extended ens and their take on the next fortnight. that the ops had not made the running as yet this season and why now ? well there is a possibility that now could be their time. we have an upcoming scenario where lots of differing parts of the hemispherical patterns are interacting at the same time. with the behaviour of the polar high also crucial to the evolution, its feasible that the higher resolution of the ops is required to pin down the pattern at day 5/6. if the ens are in the wrong place at this timescale, then what they dish out thereafter will also be out of kilter to what may verify. its a small straw to clutch but it does happen from time to time and we are due a bit of luck from a cold perspective.

Looking at the ukmo no i can't Nick.

I see a -AO signature developing but i also see a strong Euro high and an intense PV moving into Greenland with bitterly cold air spilling out of North America to feed the Atlantic jet.

To my eyes the Euro high is dictating the pattern in conjunction with the low heights to the North west....

GFS FI at least replaces the high pressure anomalies across mainland Europe.

[johnholmes]

I'm not buying this run after seeing it all, it's all very too strange and over-done. Would be great if it came off, and would tie into MetOffice long ranger, but the differences of 6 hours is ridiculous.

 

 

 

 

Something not right unless the GFS has picked up on something...

 

the pitfalls of following every run and every single chart. 

 

Beyond about 144h it really is pointless comparing one run  to the next. How does this run compare to the 12z from yesterday, not in exact detail but the overall pattern? Once down to 144h then by all means watch each run. At long time scales look for the major upper air patterns, forget the surface.

FI should be renamed FS=Fairy Stories by GFS!

Edited January 2, 2014 by johnholmes

[R.P. McMurphy]

the pitfalls of following every run and every single chart. 

 

Indeed John,

 

But one can only create a better trend by following every run and every chart, right?

Edited January 2, 2014 by Glenn W

[Stuie]

What`s the chances of both the LP`s forming a Scandi high? If we could only start to get the winds going in the right direction pulling that cold air into europe then some potential for blocking to finally halt the Atlantic train? A battleground much more favourably closer to our shores?

[Cheshire Freeze]

I've been through every ensemble member in the GEFS and the overwhelming signal in FI is to set up a much more wintry pattern for the UK in the day 12-16 timeframe.....bang on when the Metoffice see the change occurring.

 

In graphical terms...

 

Not overwhelming on 850s but they don't tell the whole story

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=224.94000244140625&y=52.279998779296875

[johnholmes]

Indeed John,

 

But one can only create a better trend by following every run and every chart, right?

 

nope not at long range-all you will get is ups and downs as the models chop and change.

I did show one way of doing checks on the probability of any single run having the correct idea. (pdf a couple of days ago, no idea where it is in this thread but it easily found on the In depth thread). It won't find favour with some on here but compare the latest 6-10 or 8-14 NOAA 500mb anomaly with the run from GFS/ECMWF at those time scales but UPPER AIR NOT surface pattern. If it is not unlike the anomaly chart then it is much more likely to verify than if it is wildly different.

[nick sussex]

I see the GFS flattens the pattern out again after more amplitude on the 06hrs run, the UKMO is close to being very good, the GEM is still more amplified than the GFS and we await the ECM solution.

 

The high to the ne is now looking like the possible trigger if it can ridge sufficiently sw and question marks over phasing of the energy over Greenland and the troughing over the UK still exist so overall then a lot of uncertainty.

 

Reading NOAA comments before the flatter GFS came out it seems as if the operationals are on the western side of the ensembles which means one of these is going to be wrong, at shorter range you would normally factor in more of the higher resolution outputs which brings to question that most of the GEFS solutions could be wrong.

 

Extended forecast discussion before the GFS 12hrs run came out liked the ECM 00hrs and the GFS 06hrs run in terms of the upstream low, will the latest GFS change NOAA thinking?

 

The updated State forecasts will be out soon so hopefully they'll shed some more light on that.

 

Diagnostic discussion update, GFS and NAM 12hrs ditched upstream for the start of the evolution of the upstream low, prefer ECM/GFS 06hrs/UKMO/GEM 00hrs outputs.

 

After all this lets hope the ECM 12hrs sticks to its 00hrs re the low!

Edited January 2, 2014 by nick sussex

[bluearmy]

 

Looking at the ukmo no i can't Nick.I see a -AO signature developing but i also see a strong Euro high and an intense PV moving into Greenland with bitterly cold air spilling out of North America to feed the Atlantic jet.To my eyes the Euro high is dictating the pattern in conjunction with the low heights to the North west....GFS FI at least replaces the high pressure anomalies across mainland Europe.

 anytime i see highish heights to our north, i like the run. the ukmo ends in a similar place to this mornings ecm 00z run which was close to being an excellent run. as steve said, the current modelling is putting the polar high on an axis which will encourage the ridge to force down in our direction. that gives a good opportunity of either a greeny or scandi ridge, or supressed zonality with the jet way south and us north of the PFJ in slack low thickness air. all supposition that the ops are on the right track days 5/6/7 and the ens are not.

[Cecil Hogmanay Melchett]

   anytime i see highish heights to our north, i like the run. the ukmo ends in a similar place to this mornings ecm 00z run which was close to being an excellent run. as steve said, the current modelling is putting the polar high on an axis which will encourage the ridge to force down in our direction. that gives a good opportunity of either a greeny or scandi ridge, or supressed zonality with the jet way south and us north of the PFJ in slack low thickness air. all supposition that the ops are on the right track days 5/6/7 and the ens are not.

Fingers crossed-i remain dubious  but my God i hope you are correct in your assessment.

[stratty]

A much better GFS already for cold fans... Arctic High force down Northerly winds...

 

 

......where? sorry 

[lassie23]

It would seem that from the comments on here this evening, the message is that the powerful jet stream is forecast to weaken come the middle of January, allowing for high pressure to set up somewhere. Mid Atlantic........ who knows! Preferably somewhere where we can actually get some cold and snow, it is winter after all, the U.S can't hog all the white stuff this winter......not fair

[bluearmy]

 

I've been through every ensemble member in the GEFS and the overwhelming signal in FI is to set up a much more wintry pattern for the UK in the day 12-16 timeframe.....bang on when the Metoffice see the change occurring. In graphical terms... Not overwhelming on 850s but they don't tell the whole story http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=224.94000244140625&y=52.279998779296875

 about half the members are interesting crewe but overwhelming ? not yet - is there a clustered pattern showing ? not that i can see although the propensity to show arctic ridges is a good sign moving forward.

[SMU]

Evening -

 

So good model continuity of the low moving up into Canada.....

 

Where to look next>????

 

As the low moving into Canada you will see the jet flow move NE across the Greenland Plateaux - whilst that's happening the jet will be streaking East under the low-

The angle & tilt will effect whether we can get the cold air over the UK...

 

Here it is on the UKMO

 

 

* The green slant shows the jet taking the ridging NE over Eastern Greenland ( & subsequent wedge of high pressure over Svalbard)

* The Red track (1) shows where the jet is going to take energy next & what will happen is you will see a shallow low possibly 2 develop under the trough base-

The track number 1 where the energy is split shows a GEM type evolution where the low doesn't really get east past the meridian

 

GEM 192

http://modeles.meteociel.fr/modeles/gem/runs/2014010212/gemnh-0-192.png?12

Note the 2 small lows following my red track-

Eventually the jet splits again to this

http://modeles.meteociel.fr/modeles/gem/runs/2014010212/gemnh-0-240.png?12

 

The purple track (2) shows the GFS all eastward solution-

 

GFS 12z

http://modeles.meteociel.fr/modeles/gfs/runs/2014010212/gfsnh-0-192.png?12

Note the 2 lows pushing East

 

GFS 12 = http://www.youtube.com/watch?v=2_FmADVggCk

 

 

So watch the ECM & the models over the next 72 hours as the detail is much more difficult as the pattern & borders of very cold V very mild will hover around the UK- could be west of us - could be East

 

S

Edited January 2, 2014 by Steve Murr

[Gaz1985]

Europe turning colder is sometimes a good sign for coldies in this country.

 

 

 

 

 

Edited January 2, 2014 by Gaz1985

[Cecil Hogmanay Melchett]

   about half the members are interesting crewe but overwhelming ? not yet - is there a clustered pattern showing ? not that i can see although the propensity to show arctic ridges is a good sign moving forward.

TBF Nick CC has forecast a January to rival Dec 2010 in terms of severity

The sheds safe btw !!

On a serious note i agree with the bit regarding the Artic high pressure cells but without a radical shift in the NAO its not going to be much use to the UK,the ways things stand  countries as far east as Poland and Ukraine will just about see the benefit.

[nick sussex]

Whilst everyone is having their nerves shredded waiting for the ECM to come out, the fax chart for T60hrs is not without interest for some possible snow on the northern flank of the occlusion, some 528 dam is associated with the precip moving in so a chance, probably marginal but I think perhaps a surprise, unlikely to hang around for too long with the next low waiting to move in. Still time for this feature to change track or disappear so not a definite just a possibility:

 

 

PS interesting ECM 144hrs!

Edited January 2, 2014 by nick sussex

[cooling climate]

I've been through every ensemble member in the GEFS and the overwhelming signal in FI is to set up a much more wintry pattern for the UK in the day 12-16 timeframe.....bang on when the Metoffice see the change occurring.

 

 

It is also very much in line with what myself and several other posters especially those following

the stratosphere forecasts could see happening during the last two weeks of January and

hopefully onwards through February.

[Cecil Hogmanay Melchett]

Europe turning colder is sometimes a good sign for coldies in this country.

 

 

 

 

 

Agreed Gaz,the trouble is the starting point is ridiculously mild its not that difficult to get a downward trend.I assume the drop in 850's is a response to the ridging from the Arctic as mentioned by Bluearmy.

ECM looks similar to UKMO at 144 so it will be interesting where we go from there...

[bluearmy]

the ecm 12z is similar to the 06z gfs to our west. will the ecm extend the trough straight across as the gfs run did or go in the gem direction ?

[bluearmy]

 

It is also very much in line with what myself and several other posters especially those followingthe stratosphere forecasts could see happening during the last two weeks of January andhopefully onwards through February.

 but not in the 11/15 day timeframe which is when events in thes strat are likely to be happening (if they verify). we then have to wait at least a few days for downwelling, even with a quick response.