Winter Model Discussion - The Hunt For Cold -12z 14/12/12

[Gavin Hannah]

Next week shows major uncertainty, the cold block is close and is ready to pounce although the latest ecm run would be coldest in the far north, the changes begin as early as monday and tuesday with cyclonic conditions and temps a bit lower than the weekend, nearer 6-8c on mon/tues following the 8-10c on sat/sun. We really need to see the troughing modelled to slip further southeast to enable to cold block more chance to dig further south and west so it wouldn't just be scotland that turns colder, but it keeps things interesting for coldies.

Agreed. The LP flattens out then reforms. I'm hoping the ECM is overdoing the reformation and the LP will slide right under.

[cold snap]

your can talk about differences all day long with the ecm v gfs but to be honest they both may give us a different mild outcome,so that holds very little interest.

This is starting to frustate me ,if the lows cant undercut ,then i hope the russia high just goes bang and we can move on from this saga.

Even if we were to get a undercut how long would it be before another low came in and traffic was diverted east again.

There is pretty good agreement tonight that the mild air will win.

This of course is not to say we maybe get to some prolonged easterly set up but it all comes back to same issue.

Greenland blocking or the lack off.

Edited December 14, 2012 by cold snap

[Frosty.]

It's just a relief that the euros are not anything like the gfs, it seems to me the gfs 12z run is a rank mild outlier and that more realistically there will be trough disruption across the uk with a colder cyclonic trend after the weekend with an increasing risk of wintry ppn as next week progresses but this is still evolving, I find it encouraging but more improvements are needed to bring a widespread return of cold air, still, we have a chance at least.

Edited December 14, 2012 by Frosty039

[Ian Brown]

Not a very good end result from the ECM but if you look at the T120-168 range there are plenty of chances for the outcome to be rather different to what it ends up showing at days 8-10.

Cold coming back from the East remains the outsider, but it's not over yet.

[cold snap]

Not a very good end result from the ECM but if you look at the T120-168 range there are plenty of chances for the outcome to be rather different to what it ends up showing at days 8-10.

Cold coming back from the East remains the outsider, but it's not over yet.

i would not agree more as my above suggest the mild air is winning the battle

Not a very good end result from the ECM but if you look at the T120-168 range there are plenty of chances for the outcome to be rather different to what it ends up showing at days 8-10.

Cold coming back from the East remains the outsider, but it's not over yet.

i would not agree more as my above suggest the mild air is winning the battle

[Gavin Hannah]

Not a very good end result from the ECM but if you look at the T120-168 range there are plenty of chances for the outcome to be rather different to what it ends up showing at days 8-10.

Cold coming back from the East remains the outsider, but it's not over yet.

No fat ladies warbling just yet!

[Froze were the Days]

Still feel we're not getting anywhere with this set up - nothing has really changed for me, the Siberian High is still there and somewhat of a 'weaker' Atlantic appears but today the models have backed of this idea of possible undercutting, please in another weeks time can we see a different pattern change even if this means that High clearing off.

[ANYWEATHER]

The cold block remains in place over to the NorthEast of the Uk. The gfs "tries" to blow that block away and the the ecm Quivvers with the idea of the cold affecting the Uk. I remain confident that this week we will see a turn around in the models and show a colder outlook for xmas ,almost so, that I feel I may have a White Christmas Bet.....!

[Frosty.]

Agreed. The LP flattens out then reforms. I'm hoping the ECM is overdoing the reformation and the LP will slide right under.

Yes there is still a lot to be resolved with the complex trough over the uk next week and how much influence the cold blocking will have, on balance, I favour a return to wintry weather for northern parts at least with increasingly cold SEly winds.

[johnholmes]

Cmon all you big guns, gp,jh,chio,bftp,teits etc. Its friday eve im opening a nice bot o red and praying for some undercutting showing soon. Taking everything into account how do you guys feel(with all your experience) these next 2 wks or so will evolve to what the models are showing? Think of yourselfs in the smoky met room in the 70s/80s about to go live with nothing but intuition and skill. Bit of fun to liven the mood!

an uncertain outlook-how is that for you?

I'll do my supposed Friday run around on the 500's etc tomorrow as not available this evening.

[Gibby]

Good evening. Here is the report on the 12zs from GFS, UKMO and EM for tonight Friday December 14th 2012. There will be no report from me tomorrow morning but I should be OK for the 12zs later in the day albeit rather late.

All models show low pressure covering much of the Atlantic Ocean and the British Isles with a front moving steadily North over Northern Britain tonight. A showery West to South-West airflow covers Southern and Western areas with this weather type extending to many other areas overnight. The weekend and start of next week shows the Low pressure filling slowly as the complex system moves over the UK before losing its identity by Tuesday.

GFS then shows a weak ridge of High pressure crosses East on Tuesday ahead of the next Low pressure zone setting up in the Atlantic. Rain moves NE over Wednesday followed by breezy NW winds and showery conditions for a time. With pressure rising to the South winds back SW by the weekend carrying very mild air NE over all areas with rain and drizzle in the North and West. Through FI tonight the trend is for the mild weather to persist in the run up to Christmas with Christmas itself shown to be very windy and wet at times with temperatures dropping back to normal or somewhat below in the period between Christmas and New Year for a time in the North.

The GFS Ensembles show very uninspiring conditions for those looking for cold and snow tonight. After a mild snap for a time next week temperatures fall back to near the normal for all areas. The colder blip from the operational after Christmas is without support with very few colder options at all through the run. There is plenty of precipitation shown for all areas through the run and virtually all will no doubt be rainfall.

The Jet Stream shows the flow blowing strongly Eastwards over the Atlantic to France over the coming 4-5 days. Later in oscillates North over the UK late next week.

UKMO for midday on Thursday shows Low pressure West of Ireland with a broad trough East over Northern Britain. Southern areas once more come under the influence of a breezy SW flow with heavy showers in generally mild conditions.

ECM shows a similar pattern to UKMO at 144hrs though with a separate Low pressure centre over the UK as opposed to the trough UKMO shows. The end result would not be too dissimilar though on the ground with outbreaks of rain and showers all over the UK in cyclonic winds. Later in the run little change is shown with Low pressure re-establishing close to the UK with further heavy rain and showers for all.

In Summary tonight it looks like a very unsettled spell of weather for all of the UK for the coming two weeks. There will be spells of rain or showers for all, always heaviest in the South and West while things remain relatively mild. GFS shows a very mild slot for a time prior to Christmas while conversely ECM shows somewhat cooler conditions, but not cold especially in the North at the same time point with rain for all. There is little desire for any model to want to bring us back under cold conditions either from the East or North through this outlook period.

[Frosty.]

There is little desire for any model to want to bring us back under cold conditions either from the East or North through this outlook period.

With respect, I don't agree with your summary, there is way too much uncertainty regarding next week to be so bullish about the outlook, noticed even john holmes thinks it's uncertain.

[legritter]

JUST lost a whole post oh well ,ECM at 168 hrs is my straw to clutch ,but it could go anyway ,perhaps we are heading to a very cold zonal , GFS all over the shop at present , but a very cold zonal can deliver iv seen some classic synoptic situations described in some of my journalls .perhaps tomorrows uk met 144 hrs will give us a clue . and in cyclonic situations this time of year if we can get some good 850 temperatures we could have some happy posters .looking for some frost just before big day to give me sprouts a good taste .anyhow lets see what the gfs shows soon and tonights fax At 120 hrs cheers

[Liam J]

With respect, I don't agree with your summary, there is way too much uncertainty regarding next week to be so bullish about the outlook, noticed even john holmes thinks it's uncertain.

Yes but Martin summarises the current model data from the 12z suite, so his summary his perfectly valid given this evenings outputs - they do look poor for cold weather, removing all the ifs buts and maybes. When they do show a possible cold outlook then this get included into his UNBIASED summaries.

[Frosty.]

Yes but Martin summarises the current model data from the 12z suite, so his summary his perfectly valid given this evenings outputs - they do look poor for cold weather, removing all the ifs buts and maybes. When they do show a possible cold outlook then this get included into his UNBIASED summaries.

Just to be clear, I normally agree with gibby's posts but tonight I don't because we have had some positive runs for cold to return, last nights ecm, this mornings ecm and to a lesser extent tonights ecm, also the ukmo and occasionally from the gfs, I think most on here will agree that the outcome next week is a long way from being resolved one way or the other, cold cannot be ruled out which gibby seems to have done rather dismissively.

[WhiteFox]

Still feel we're not getting anywhere with this set up - nothing has really changed for me, the Siberian High is still there and somewhat of a 'weaker' Atlantic appears but today the models have backed of this idea of possible undercutting, please in another weeks time can we see a different pattern change even if this means that High clearing off.

The 12z GFS shows just such a possible pattern change: the azores high ridging into Europe and a strong PV to the NW. As Ian Brown often points out, thats a pattern that can take a while to shift and delivers cold for nobody so be careful what you wish for!

As it is, we've seen the GFS crank up the PV to such levels a few times over the past few weeks and it hasn't happened on any occasion (yet!) So I'm not too worried.

[snowking]

Well some slightly more encouraging signs from the MJO, with both the ECM and GFS suites moving things towards phase 3 - which at least raises heights out in the atlantic (Should be read - potential for reduction of atlantic energy), and also suggests the height anomaly over Siberia would ridge westwards

How much of a driver is the MJO at present? Well the currently progged transition into phase 2 corresponds well to the impending pattern:

SK

Edited December 14, 2012 by snowking

[suxer]

Would'nt gibby's excellant anylasis be better suited to a specific thread (members forecast thread) instead of being lost in the fast paced model discussion thread ?

[phil nw.]

Just to be clear, I normally agree with gibby's posts but tonight I don't because we have had some positive runs for cold to return, last nights ecm, this mornings ecm and to a lesser extent tonights ecm, also the ukmo and occasionally from the gfs, I think most on here will agree that the outcome next week is a long way from being resolved one way or the other, cold cannot be ruled out which gibby seems to have done rather dismissively.

In fairness Frosty Gibby is calling what the 12z Models show not what could happen- just as Liam J was suggesting.

I like your optimism though and let`s hope we see some colder runs soon.

[Duane S.]

With respect, I don't agree with your summary, there is way too much uncertainty regarding next week to be so bullish about the outlook, noticed even john holmes thinks it's uncertain.

Completely agree. How anyone can go for "2 weeks of very unsettled weather" is beyond me. Could be for sure but no done deal yet.

GFS seems completely out of kilter later on, setting up a very zonal end of the year look. I don't buy that at all.

ECM retains the hope, a watered down version of last night's but along the same lines at least which is a nice straw to clutch at right now! UKMO raw not too far away as well. Neither really manage enough tough disruption to set off the favourable downstream domino effect we crave here (well, most of us anyway)

As I said yesterday, don't look out for massive northern blocking in the next 10 days, it isn't going to happen but I do see a potential appearance of a breakaway cell around about 65 deg N, could be enough to help persuade the jet to head a bit further south and we're off.....

If you're feeling glum after today's offerings I would prescribe a good movie. Not one on the TV but a classic Wetterzentrale blockbuster like Dec 62 - March 63. A timeless classic guaranteed to make you smile! Also makes you realise how innocuous conditions often were before the onset of a prolonged cold period.

[cerneman]

Would'nt gibby's excellant anylasis be better suited to a specific thread (members forecast thread) instead of being lost in the fast paced model discussion thread ?

Find Gibbys posts very good to give daily overview.which sometimes can be lost in here, Long may Gibby reign [no pune intended]

[phil nw.]

Would'nt gibby's excellant anylasis be better suited to a specific thread (members forecast thread) instead of being lost in the fast paced model discussion thread ?

They are usually copied in the Summaries thread here suxer.

i will paste his latest one in there.

[Paul T]

So a slight difference between the GFS & ECM!

http://www.wetterzen...cs/Recm1681.gif

http://www.wetterzen...s/Rtavn1681.png

My monies on the GFS; At times of disagreement of this nature It is usually the case that the model showing the most mild/zonal weather is consequently agreed with by the other.

[Frosty.]

My monies on the GFS; At times of disagreement of this nature It is usually the case that the model showing the most mild/zonal weather is consequently agreed with by the other.

LOL the gfs is all over the place showing wildly different outcomes every run, for consistancy, the ecm is more solid and that's not because it shows a possible colder trend, gfs is very unreliable.

[bluearmy]

ecm ens spreads show an appetite to bring an easterly into the northern half of the uk with a small shortwave headed across southern england days 9 and 10. that would be interesting for the midlands. definitely a trend for the energy to be displaced further south. looks like a few clusters by day 10.