Model Output Discussion 12z 30/11/2012

[phil nw.]

The operational ECM/GFS mean hts 168-240 show the disagreement with the building UK High from the end of next week

On the GFS run there is little sign of low pressure to our south supporting the high and this would likely sink it in time with more energy further north.

The ECM gives a more secure height build with those euro low hts from the cut off trough and would trap the cold air over the UK-a more Wintry feel with frosts and perhaps freezing fog patches.

Unless the height anomaly forecasts have suddenly changed since the 00z runs then you would favour the ECM to be nearer the solution

ie,Low hts sinking south east into Europe and the higher pressure in the north west Atlantic ridging towards Scandinavia.

Edited November 30, 2012 by phil n.warks.

[stainesbloke]

High pressure sitting over the UK would be a bit of a novelty in itself! Last time that happened was March, wasn't it? As long as its a sunny high it will stay cold and feel like Winter, can't complain.

[swilliam]

The CFS is giving the vortex to us for Christmas

[Grimsby Snow Lover]

The CFS is giving the vortex to us for Christmas

Just out of interest apart from wind what would a chart like that deliver for the UK?

[stainesbloke]

Just out of interest apart from wind what would a chart like that deliver for the UK?

Blizzards!!

[Matty M]

I think one almost gets a better overview of the models if you aren't too involved which i havent been for past few days.

I sense a trend for High Pressure developing in and around the UK, could be cold, could be mild.

With generally the jet moving to our north from Day 7 and little likelihood of a severe cold & snowy outbreak in the next 14 days.

Infact the outlook appears to be deteriorating around the Pole for our location anyway. Yes disruption near the Aleutians.

[Ice BIast]

Quite cold ECM ensembles tonight:

BTW, does anyone have a link to the site that shows all the ECM ENS members up to T168?

Edited November 30, 2012 by lce Blast

[SMU]

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

OOFT.....

HUGE swing to cold from nearly all the ECM ensembles tonight with the OP a slight mild outlier.-

S

[NL]

The 500Mb cpc 8-14 day still shows an E/NE flow straight off the continent.

[Jason M]

Just out of interest apart from wind what would a chart like that deliver for the UK?

Rain mostly. The blues and purples don't reflect the temperature on this chart. I'd imagine 850s would be circa -2 to -4 but with a maritime influence it's wet rather than white unless you live on high ground.

Jason

[January Snowstorm]

I think one almost gets a better overview of the models if you aren't too involved which i havent been for past few days.

I sense a trend for High Pressure developing in and around the UK, could be cold, could be mild.

With generally the jet moving to our north from Day 7 and little likelihood of a severe cold & snowy outbreak in the next 14 days.

Infact the outlook appears to be deteriorating around the Pole for our location anyway. Yes disruption near the Aleutians.

I think you must have had a bad day Matty because the general view is that things have turned much more in our favour over the last 2days.

My own opinion is that we will be staring down the barrell of a sever cold spell by Sunday night

[Matty M]

http://www.knmi.nl/e...M_06260_NWT.png

OOFT.....

HUGE swing to cold from nearly all the ECM ensembles tonight with the OP a slight mild outlier.-

S

This is to do with a high pressure near the region. It does not necessarily indicative favourable conditions for the majority of the UK.

[nick sussex]

Quite cold ECM ensembles tonight:

BTW, does anyone have a link to the site that shows all the ECM ENS members up to T168?

Here you go:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

Some cracking members there but still quite a variation of solutions.

[tcc]

Yes Steve that is interesting, we need to see if this is consistent over the next few days before we can a degree of confidence. Having UKMO on board also would be good!

[Matty M]

I think you must have had a bad day Matty because the general view is that things have turned much more in our favour over the last 2days.

My own opinion is that we will be staring down the barrell of a sever cold spell by Sunday night

Hi JS, My read from the output is that the only place that is likely to get severe cold/snow for a period is the Kent coast. So the positivity on here may be to a degree slightly warranted. But i wouldnt be too optimistic if i was north of the M4 corridor. Definitely not in Ireland. Hope i am wrong.

[SMU]

This is to do with a high pressure near the region. It does not necessarily indicative favourable conditions for the majority of the UK.

HUM- Matty unlikely you get those temps at that steep gradient of decline just from an inversion-

Would need cold to mix down to start with!

S

[Grimsby Snow Lover]

HUM- Matty unlikely you get those temps at that steep gradient of decline just from an inversion-

Would need cold to mix down to start with!

S

Going by those ensembles should we expect the GFS/UKMO to come on board in the next few days regarding a pressure build over Scandinavia as per ECM or is this another false dawn?

[Jason M]

The postage stamps are very good from ECM based on the above. Lots of NE options. That said, don't discount the dreaded uk high scenario. Nothing good ever comes from these and a few have shown in the longer term output in recent days. ECM tonight though is very positive.

Jason

[Mark Neal.]

Amazing how different people interpret models. Over on TWO on twitter they are suggesting a Bartlett setting up for 6 weeks for mid December onwards.. Anyway nice to see the ensembles showing colder, a trend hopefully will be continued!

[SMU]

Going by those ensembles should we expect the GFS/UKMO to come on board in the next few days regarding a pressure build over Scandinavia as per ECM or is this another false dawn?

The Link with the scandi high is tentative from an atlantic ridge & a ridge east of Scandi- the link looks tenuous, so subsequent cold air is undecidied yet-

More runs needed- probs another 48 hours-

S

[Matty M]

HUM- Matty unlikely you get those temps at that steep gradient of decline just from an inversion-

Would need cold to mix down to start with!

S

The ECM EPS is not bad at 168hrs

My interpretation is for a high to set up over UK into Atlantic and give easterlies into central Europe and perhaps Kent, mid France.

[Jason M]

Amazing how different people interpret models. Over on TWO on twitter they are suggesting a Bartlett setting up for 6 weeks for mid December onwards.. Anyway nice to see the ensembles showing colder, a trend hopefully will be continued!

It's not without some credibility IMO. Not sure about a full fledged Bartlett, but a slow sinker uk high can easily swallow up a few weeks and leave a zonal pattern in its wake in our part of the world. The GFS ensembles show some support for this, although ECM snapshots posted by others show an E or NE flow. My head says ECM but my gut screams UK High from mid Dec onwards. As Steve Murr has said 48 hours should see the fog clear somewhat.

[Matty M]

My philosophy and i have seen it played out so many times. You need a nice Greenland High with real 500mb heights over Greenland for a prolonged cold spell for my location anyway.

Obviously there are exceptions but in the majority of cases it is necessary. With the PV in Hudson and so close to Greenland and progged to be over some parts of it. I just cannot see anything prolonged.

[Methuselah]

My philosophy is: don't think too far ahead...What would we have made of this:

http://www.wetterzentrale.de/archive/ra/1962/Rrea00119621203.gif

[Glacier Point]

Ahhhhhh December '09......now that was a cold December with 'proper' blocking, along with the first half of the Jan that followed. Magical time that We are, sadly, a fair way from that in the next 10 days or so.

Weighing up what I've seen today, nothing has really persuaded me that we won't see a mid lat high set up in 7-10 days time,dictating the UK's weather.

I disagree.

December 09 surface values 1-15

December 09 surface values 1-30

Projected GEFS 850s (which might undercook surface values given synoptic) for days 6-10 and 11-15 December 2012

Controversially, the first half of this month will rival or beat December 2010 if continued:

-3.5C the goal to aim at.

Edited November 30, 2012 by Glacier Point