Model Output Discussions 06z 04/11/16

[mpkio2]

The new ECM makes its grand opening in style!

ECM 12z t144:

ECM 12z t240:

Takes a completely different route than GEM/GFS and UKMO, but still has height rises to NW.

FL, obviously, so not to be taken to seriously. It's just interesting, once more, that its picking up some signal for more height rises.

All in all, very good bag of 12z's today. Hopefully the trends will continue in this never-ending rollercoaster!

~mpkio2~

[damianslaw]

Taking note of the met office long range forecast its perhaps not a surprise to see the models showing a slow evolution to something much colder eventually.. as some have said patience is the word. A look at the models and they are all in agreement that we have and will continue to have a highly amplified flow, complete opposite to normal conditions at this time of year - indeed we are now entering the 3 week period of the year, when westerlies traditionally are most dominant, not this year by the looks of things.

I said yesterday focus on the ensembles and trends generally in terms of northern hemispheric base state - all signify developments highly conducive to an anomalous pattern as we move through December, and one ripe for possible significant cold, if things fall into place.

I suspect if the ECM went out to 268 hrs it would be showing sub 528 dam air invading across the country on a potent northerly flow.

[nick sussex]

It will be interesting to see whether the GFS continues with its upstream view of holding that Newfoundland low back and not phasing it with the one near Greenland. Its evolution is reliant on the non phasing and the nose of high pressure holding that back. The other outputs phase those lows so its very much the GFS on its own here.

So far at T90hrs similar over the eastern USA but the low near Greenland is sharper and further west, could lead to the high getting a bit further n/nw to the north of the UK.

Edited November 22, 2016 by nick sussex

[feb1991blizzard]

Better GFS than 12z, more amplified, better ridging, further West at just 84, only problem is it is likely it wil be 'too amplified' and end up west based.

[Snowy L]

Everything seems a 100 miles further west than on the 12z so far.

[fergieweather]

51 minutes ago, damianslaw said:

I suspect if the ECM went out to 268 hrs it would be showing sub 528 dam air invading across the country on a potent northerly flow.

There's marked ensemble spread in 500hPa GPH plumes post-29th Nov, with no *firm* evidence - yet - for pronounced cold weather in the 12z extended clusters (= just as many less cold members). 

Edited November 22, 2016 by fergieweather

[Ice Day]

Some proper cold within touching distance at 138hrs.  Few more westward corrections and it really could be game on here.

[Ali1977]

On 22/11/2016 at 22:14, fergieweather said:

There's marked ensemble spread in 500hPa GPH plumes post-29th Nov, with no *firm* evidence - yet - for pronounced cold weather in the 12z extended clusters (= just as many less cold members). 

Hopefully over the next few days the balance tips in favour of cold - although noted that towards the middle of the month now looks better than early ref cold. 

[marksiwnc]

5 minutes ago, fergieweather said:

There's marked ensemble spread in 500hPa GPH plumes post-29th Nov, with no *firm* evidence - yet - for pronounced cold weather in the 12z extended clusters (= just as many less cold members). 

Hi Ian is Nxt weeks breakdown from the west /NW a guarantee according to your models or are they like all other models getting conflicting info and anything is virtually up in the air? 

[nick sussex]

The GFS still holding on to the non-phase within T168hrs but I'd still put this as the outlier solution. The last disagreement we had was between the ECM versus the GFS/UKMO upstream within the T144hrs mark and the ECM won that hands down. It threw a shortwave east the GFS in particular wanted to build that stronger ridge to the north. The UKMO backed down more quickly so I'm a bit dubious of the GFS.

Anyway putting that aside theres good agreement on a spell of welcome drier and calmer conditions for the UK, in terms of frost and fog that seems likely especially once the winds switch round to a more ese which might bring in some more widespread clearer conditions from the continent.

[Allseasons-Si]

The Newfoundland shortwave is none existent on this run,cleaner evolution coming up me thinks

then adds the extra bag of energy come 192 hrs,could still drop a few surprises in the later frames.

this could be a belter come 240 hrs.

i have to take a break from this model malarkey ,catch you in the morning

Edited November 22, 2016 by Allseasons-si

[Frosty.]

 

Plenty of cold, crisp frosty fine weather on the Gfs 18z, a nice wintry feel and signs of an Arctic spell further ahead..This looks a much better run (for coldies) than recent 18z's

Edited November 22, 2016 by Frosty.

[blizzard81]

Everyone glued to the 18z. Why? Because it's not going down the bartlett route like it's two previous runs.

[Cheshire Freeze]

N'ly ready to blow?

[feb1991blizzard]

Just now, CreweCold said:

N'ly ready to blow?

Could be a full on blizzard in the next few frames.

[SMU]

Evening All -

Some surprising discussion today around the period of end of November -

Ive seen posts quoting why still 'no deep cold' , GP posting about the period 12-16 day period & cross polar ridging- perhaps that torpedo might finally land -& the met office perhaps moving away from the end of November blocking forecast + Cohens update -

To be frank here the forecast period for UK specific is impossible post day 6,although with a footnote that there has been a move today in the 168-192 to increase the canadian heights which are migrating steadily eastwards with time, this perhaps has tipped the balance slightly again towards UK cold however it really depends as much on the ridge as it does on the eastward progression - We could still end up on the warm eastern side of the trough in a slightly west based NAO -

In terms of context 'Globally' this Oct/November so far has been unprecedented, we have record warmth in the arctic, record low ice expansion, record high SAI, record -AO oct, Record late ice loss & finally a record low ( forecast for ~27th) 60N zonal mean -

 

The net result from this has been that all the 'deep cold' has been locked into Siberia / Russia - & with the time of year making it difficult to tap a long fetch easterly then deep cold was never likely -

However as has been mentioned the cold now is beginning to back west being supported by the core of the vortex being displaced-

The last 96 hours has seen the models moving from forecasting a deeply negative AO to a weak negative AO - this has reflected in the models from the Met & the strat - by seeing an uptick in westerly flow -

But I still believe the dates 29/30th hold the key whether we can attenuate enough for cold - if we do the AO means will drop as will the zonal mean forecasts-

So deep cold - not yet- but decent cold available from 30th still much in the frame -

S

 

[nick sussex]

The differences at T240hrs between the GFS 18hrs and GFS 12hrs are huge and run to run continuity has imploded. For this reason attempting a forecast for next week looks like a complete lottery. There are some cold and possibly wintry chances on offer but you really wouldn't want to put too much money on this given the UK's propensity to clutch defeat from the jaws of victory.

[Banbury]

Much better as cold air floods in from The North

On the colder side of the ENS I would imagine

[Frosty.]

What a cracker the 18z is turning into

Edited November 22, 2016 by Frosty.

[Ali1977]

For fun but great GFS, could that WAA head NE and create a scandy high.  Nope!! 

Edited November 22, 2016 by Ali1977

[Allseasons-Si]

3 minutes ago, CreweCold said:

N'ly ready to blow?

Knockers blowtorch isn't working

i will have a blue torch instead

 

[nick sussex]

Amidst all the chaos that ridge in the east Pacific survives the confusion and the upstream pattern is expected to re-amplify but apart from that the models look a mess.

[feb1991blizzard]

A belting for large swathes of the country between 240 and 288.

[Banbury]

Some of you best get a snow plough  J F F

[Frosty.]

Well what a run for coldies, makes up for the last 2 Gfs 18z low res mild mush fests!

Severe frosts, ice days and snow

Edited November 22, 2016 by Frosty.