Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Stuie]

If only. FI is for life not just for Christmas.

[Frosty.]

Hmmm i dont think you should say that with confidence, as 12 out of the 20 ensembles show -0C upper temperature over the UK, which isnt mild nor cold, none of them either are going for very mild neither. Not to put you down as things can change just telling you what the models are telling me atm. http://www.meteociel...&mode=0&ech=180 Perturbation 14 floats my boat! http://176.31.229.22...ns-14-0-192.png

Hmmm, well peter gibbs, mr mild himself just said it, unsettled and milder with a bit of snow for the scottish mountains only up to and throughout christmas, there you have it from the horses mouth! As for the models, nothing at all has changed my opionion that christmas will be at least mildish and probably very mild, the gfs 00z is a cold outlier, a mild christmas on the way.

[Iceaxecrampon]

^{Hmmm, well peter gibbs, mr mild himself just said it, unsettled and milder with a bit of snow for the scottish mountains only up to and throughout christmas, there you have it from the horses mouth! As for the models, nothing at all has changed my opionion that christmas will be at least mildish and probably very mild, the} gfs ^{00z is a cold outlier, a mild christmas on the way.}

^{Reverse psychology Frosty.........?}

^Ian

[Frosty.]

^{Reverse psychology Frosty.........?}

^Ian

[Polar Maritime]

Hmmm, well peter gibbs, mr mild himself just said it, unsettled and milder with a bit of snow for the scottish mountains only up to and throughout christmas, there you have it from the horses mouth! As for the models, nothing at all has changed my opionion that christmas will be at least mildish and probably very mild, the gfs 00z is a cold outlier, a mild christmas on the way.

Your stance seems to be working Karl..

Models are looking better this morning for cold around the Christmas period

[trickydicky]

Hmmm, well peter gibbs, mr mild himself just said it, unsettled and milder with a bit of snow for the scottish mountains only up to and throughout christmas, there you have it from the horses mouth! As for the models, nothing at all has changed my opionion that christmas will be at least mildish and probably very mild, the gfs 00z is a cold outlier, a mild christmas on the way.

Blatant, brazen reverse psychology. Christmas is one day out of the year, I'd happily take a mild Christmas for a cold spell starting boxing day. The models are toying with colder options and Christmas day is still comfortably in FI.

[Bristawl Si]

Taken from Matt Hugo on the strat forum:

"NB: EC 32 day update shows higher pressure once again become more influential across Greenland and surrounding areas with time as low pressure dominates to the W or SW, so an increasing signal for a -AO and a -NAO pattern. The ECMWF 32 day forecast for the MJO takes it out of phase 1 and firmly into phase 2 and 3 as well FYI."

So this model flips once again - how many times is that in the last 6 weeks or so?

[Frosty.]

Blatant, brazen reverse psychology. Christmas is one day out of the year, I'd happily take a mild Christmas for a cold spell starting boxing day. The models are toying with colder options and Christmas day is still comfortably in FI.

Are you suggesting peter gibbs, the respected mild loving weatherman could be wrong?

I agree that beyond the big day it could turn much colder according to the signals from ukmo 00z, as others have said.

[Duane S.]

Pretty good charts again this morning, GFS pick of the bunch (uh oh). It sends a fair chunk of energy S and ends up giving many some festive snow. Therafter it gets across to the North sea and from here we could get a decent Northerly evolve. The general theme of energy being transported across Atlantic continues in different guises. I wouldn't be surprised to see mid-Atlantic ridging showing up in deep FI over the coming days. To be honest I wouldn't be suprised to see anything on the charts in the next couple of weeks as the models start to get to grips (or not) with the Strat warming episode.

I think what we are seeing though is the Russian block slowly but surely losing its grip over the next couple of weeks. A good thing I recokon as with the current profile it doesn't really have a role to play (yet) and there is a real danger of us being sat in no mans land if it loiters.

[Ian Brown]

Little support for the GFS op:

http://cdn.nwstatic....erdeenshire.png

That is for those cold uppers in the north around Christmas Day. If it is an outlier up there then down south is likely to be similarly unlikely. Hopefully a trend though.

The mean from the GEFS:

http://modeles.meteo...-21-1-192.png?0

The ECM says cyclonic westerlies:

http://www.meteociel...1-168.GIF?18-12

Ditto UKMO:

http://www.meteociel...44-21.GIF?18-06

Another false dawn by the GFS? Still seven days to go, so who knows. Positive signs elsewhere:

Taken from Matt Hugo on the strat forum:

"NB: EC 32 day update shows higher pressure once again become more influential across Greenland and surrounding areas with time as low pressure dominates to the W or SW, so an increasing signal for a -AO and a -NAO pattern. The ECMWF 32 day forecast for the MJO takes it out of phase 1 and firmly into phase 2 and 3 as well FYI."

I think the GFS has 'thrown one in' this morning, it often over develops a system and then that throws the whole run off at a tangent. I still would not be rock solid confident that nowhere in the UK will get a white Xmas though, as the models are so volatile.

As for this ECM 32 dayer, let's consign it to the bin, it appears to be no better than any or other long range tool and has only served to get people's hopes up or then depress them in equal measure over recent weeks.

[Tim Bland]

GFS op is supported by the control run. IMO this is very important and shows the GFS could be onto something !

[cold snap]

http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=144&nh=1&archive=0

Mmmmmm interesting I think the ukmo at 144 isn't bad not for the easterly but look maybe a chance of pressure into Greenland

Edited December 18, 2012 by cold snap

[ANYWEATHER]

Are you suggesting peter gibbs, the respected mild loving weatherman could be wrong?

I agree that beyond the big day it could turn much colder according to the signals from ukmo 00z, as others have said.

As far as Im concerned there is no done deal for Christmas day itself. Yes, it looks more likely to mild rather than cold, as this is a normal default pattern for the Uk as a rule at this time of year, but no one can call what the weather will be doing in a weeks time ,especially given the high frequency of inaccurate model output as of recent weeks even in a so called reliable timeframe.

[cold snap]

Depends what you what if you want a another go at that easterly it's gfs

If you want pressures rises around Greenland after Christmas Ecm Ukmo look pretty decent to me

All in all not a bad output this morning

Edited December 18, 2012 by cold snap

[TEITS]

Another day and if anything even more confusion. Lets just look at +144 for example.

UKMO

The first SW is further N than previous runs thus reducing the chance of the cold E,ly in Scotland and then the LP is centred over Ireland bringing a mild SSW,ly flow.

http://www.wetterzentrale.de/pics/Rukm1441.gif

ECM

The first SW is further S than the UKMO which would bring a colder E,ly flow into Scotland. However at +144 it differs to the UKMO taking the LP further S to be centred S of Iceland.

http://www.wetterzentrale.de/pics/Recm1441.gif

GFS

Again track of the first SW is further S than the UKMO bringing a colder E,ly flow to Scotland. However the most important difference is the LP tracks E to become centred over NE England.

http://www.wetterzentrale.de/pics/Rtavn1441.png

GEM.

Very different again with the SW much further N and then LP is centred further SW

So in summary the models still can't disagreement with the track of the first SW at +60 - +72. We then see even more difference with regards to the positioning of the LP which has massive ramifications for the UK. The 0Z GFS is supported by the GEFS control by the way.

[Tim Bland]

GFS is the best possible outcome this morning. BOM looks ok for Xmas with a northerly http://www.meteociel.fr/modeles/bome_cartes.php?ech=192&code=0&carte=0&mode=0&archive=0

[TEITS]

NAE at +48.

http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2012/12/18/basis00/ukuk/pslv/12122000_1800.gif

So on the next run will this continue to push E/SE/NE??

The other thing I forgot to mention is the other SW developing underneath the main LP. The UKMO doesn't really develop this feature compared to the 12Z but this is another factor. The track of these SW systems could have an impact on what happens at +144 and beyond.

[swfc]

NAE at +48.

http://expert-images...122000_1800.gif

So on the next run will this continue to push E/SE/NE??

The other thing I forgot to mention is the other SW developing underneath the main LP. The UKMO doesn't really develop this feature compared to the 12Z but this is another factor. The track of these SW systems could have an impact on what happens at +144 and beyond.

teits what are the redlines indicating on that nae chart and where do you find these charts.thanks in advance

[Gibby]

Good morning. Here is my take on the 00zs from GFS, UKMO, GEM and ECM for today Tuesday December 15th 2012.

All models shows a very unsettled and turbulent spell of weather between now and Christmas with a block of cold High pressure maintained over Europe and the UK being the battleground between the mild Atlantic, pumping disturbance after disturbance into the UK from tomorrow on. Details are vague but the message for the remainder of the week and weekend after today is that there will be plenty of rain moving into the South and West of the UK with flooding issues a real possibility for some here. Further North and East the rain will be slower to arrive and lighter with colder air brought in from Europe in the SE flow, especially to the far North and East where the rain could occasionally fall as snow. Temperatures will range from above normal in the SW and below for much of the time in the far NE.

GFS then shows a deep Low over NE England over Christmas Eve with rain and gales for many Southern areas while Scotland on the cold side of the Low may see some snow in a strong East wind. Christmas Day shows the cold air over Scotland sweep South as the Low stays out in the North Sea with wintry showers driven SE on the strong NNW wind. Boxing Day shows rather chilly and wet conditions as further disturbances run into the UK from the North Atlantic with the chance of further wintriness on Northern hills and mountains. FI this morning shows a trend to drier conditions for a while in the South as High pressure ridges in before a return to windy and stormy conditions arrive as we move into the first few days of the New Year.

The GFS Ensembles show a sine wave pattern within the individual members indicating very changeable and often wet conditions as a succession of Low pressures bring various air masses across the UK from time to time. A lot of spread is shown between the members again from mid run with the Christmas period showing normal 850's. Using the ensembles as a guide the events of Christmas explained above are shown as a cold outlier within the group so chances of a white Christmas are slim with rain the more likely outcome.

The Jet Stream shows a continuation of a strong flow across the Atlantic undulating North and South between 45 and 55 deg North over the Atlantic the UK and Europe.

UKMO for midnight on Christmas Eve shows Low pressure close to SW Ireland with a strong South or SSW flow over the UK with troughs moving NE over the UK delivering spells of rain and showers in relatively mild conditions, especially in the SW.

GEM for Christmas Eve shows a similar synopses at Christmas Eve as UKMO moving the Low NE through Christmas Eve and Christmas Day to the NE pulling rain and strong winds to all areas followed by a NW wind and showers for Boxing Day in fresher conditions. Then towards the New Year things are shown to become milder as winds back West and a North/South split develops with the wettest weather reverting to the NW in fresh SW or west winds.

ECM for Christmas Eve shows deep Low pressure out in the Atlantic with a strong South to SW breeze bringing rain and showers NE over Britain. Christmas Day and Boxing Day sees the Low drift over Northern areas with further very unsettled and wet weather for many in strong to gale SW or West winds by then. By the end of the run the Low has made its way out to the North Sea bringing rather colder and showery conditions steadily across the UK with some wintry showers then on high ground in the North.

In Summary there is a lot of very unsettled weather to come as we move up to and over the Christmas period. There is a strong possibility of more flooding over South-western Britain as a succession of fronts bring freqent spells of heavy rainfall here with some strong winds at times. Further North and East will see rain at times too but with winds in the SE here there is colder air not far away over Europe and at times this may spread across from Europe to NE areas with rain turning to snow at times in the far NE. A white Christmas is unlikely for many as things stand currently away from the aforementioned high Northern elevations with widespread frost and fog unlikely too as winds will be too strong and cloud amounts too large for much of the time. As we look towards the New Year there are a variety of options shown this morning between the operationals but none of them show anything dramatically wintry as things stand so travelling over the Christmas period will probably not be disrupted by meteorological factors away from the very wet and potentially flooded parts of the SW.

[TEITS]

teits what are the redlines indicating on that nae chart and where do you find these charts.thanks in advance

Here we go.

http://www.weatheron...&ZOOM=0&PERIOD=

The red lines are SLP that is 1015mb and above. So basically red is suggestive of high pressure, blue low pressure.

Brave of you to do a summary Gibby. I would of just said the models are useless and don't have a clue. Would of saved alot of typing.

Edited December 18, 2012 by THE EYE IN THE SKY

[BLAST FROM THE PAST]

Well the drama continues. GFS develops into a run and an outcome that oldmetman has alluded to. The LPs not progressing NE and getting flattened elongated as they do. That would bring snow for many on Christmas week....interesting. Battleground around Britain, with Atlantic thumping away, block to NE just absorbing the blows and not budging. This may hint at what may happen as we head through winter suggestive that the Atlantic, PV will not dominate.

The ECM and UKMO to an extent, head towards a scenario I've touted where by the troughing transfers towards Scandi bringing a disturbed, stormy Xmas leading to a NW'ly into northerly afterwards. All in all though the pattern is looking good, with the AZH/Iberian HP becoming less and less of a player. More interesting model watching to come for sure.

BFTP

Edited December 18, 2012 by BLAST FROM THE PAST

[swfc]

Here we go.

http://www.weatheron...&ZOOM=0&PERIOD=

The red lines are SLP that is 1015mb and above. So basically red is suggestive of high pressure, blue low pressure.

Brave of you to do a summary Gibby. I would of just said the models are useless and don't have a clue. Would of saved alot of typing.

cheers

[johnholmes]

A look at what ‘Might’ happen over the Christmas week from the anomaly charts etc

I showed the 30mb temperature trend and suggested that there was evidence that the type of spike shown on the link below, it started 1 December, had in the past led to cold spells in the UK, 2008/9 and 2009/10 were examples.

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

Judging from the anomaly charts, both NOAA and ECMWF-GFS there is nothing to support this idea. There was one brief blip, chiefly on the GFS output that did suggest there might be something developing around the Christmas period but it lasted just one day and then disappeared. This could mean that there would be a cold blip sometime over the Christmas period but it would be a 24-36 hour shot only IF that.

6-10 day NOAA link

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

and the 8-14 day outlook

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

As you can see none of them suggest anything but a fairly strong westerly flow across the Atlantic into the country, probably mostly below average temperatures, quite likely windy at times as lows track close by. Snow unlikely except on the higher parts in Scotland-the ski areas may do quite well. Just that small chance of a 24-36 hour blip sometime over the festive period but impossible to give any dates. If this did occur then a chance of some sleet or snow further south to lower levels but not lasting even if it did occur.

Enjoy the walk in a green countryside on Christmas morning for most of us!

Just how prevalent the high will be E/NE of the UK is perhaps the largest unknown-as they say keeeeeeeeeeeep watching the models!

[MKN]

For anyone wanting to see the fun and games that could be on offer for Scotland and northern England just check the 00 gfs precip type charts from 108 all the way to 192. hopefully the 06 continues along the same lines.

[Frosty.]

Enjoy the walk in a green countryside on Christmas morning for most of us!

Exactly what peter gibbs thinks, but what do you mean by most of us? does that mean you think it will be cold somewhere in the uk on christmas day?