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

[Stuie]

Things must be edging west somewhat because images like this were nowhere to be seen over the weekend. Maybe a little battle could end up over us even if it is just the eastern areas. As I said this is new charts/hope.

[Panayiotis]

For the 26th of December most perturbations show the UK in subzero uppers, i would suggest from this that the UK may experience a cold spell, Fi however but the signal is strong.. http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=0&ech=240

[The PIT]

Excellent run for Scotland and Northern England and just slipping within the reliable time frame. Annoyingly just too far north for me. Grrr. Too early for xmas predictions. At the moment mild air pushing north which then gets mixed out. I think all eyes this weekend really before thinking about xmas. If the mild air continues getting pushed further south it could well end up a cold xmas.

[chris55]

The resilience of the Scandi high/cold air up against the Atlantic has been underestimated by the models in the mid term (180ish) and as we have come closer to the time the "lump" of cold just to the east has deflected the Atlantic Lows, causing disruption and undercuts.

So when looking ahead into the 180 time frame again it would be reasonable to assume that once again the models will deal with the interaction between the two air-masses with difficulty. So as many have said the models look to be quite unreliable in the mid term at the moment and that is something we should keep in mind when looking at the Ops and the ensembles at the moment.

[Frosty.]

I think NE Scotland could get a good few inches of snow from thurs night/friday and through most of the weekend, maybe a snowchasing tour to wick should be organised? orkney and shetland have an even higher risk. Lets see if the ecm 12z builds on that or destroys it.

[The Eagle]

ECM looks poor at 96hrs away from far northeast of scotland.

[Paul T]

The GFS rolling out shows a low over France at 96hrs what is going on?!

[itsnowjoke]

Wow what a turn around i have not.. did not dare look on here for the last few days well not propaly as i did not like what i was reading. But maybe things are looking up ...maybe.

The GFS rolling out shows a low over France at 96hrs what is going on?!

what would that mean for us??

[Panayiotis]

The GFS rolling out shows a low over France at 96hrs what is going on?!

Do you mean ecm?

[Summer Sun]

GFS 12z ensembles

A few of those members are trending to -10 now

[chris55]

ECM at 120, will we get some energy once again heading south east, squishing the Iberian ridge??

[Frosty.]

ECM looks poor at 96hrs away from far northeast of scotland.

http://www.meteociel...CM1-96.GIF?17-0

Yes it looks like a downgrade compared to the ukmo, turning wet, windy and milder from midweek onwards for all areas.

And that's what bbc news 24 just said, milder and wet from midweek, no mention of any cold anywhere!

Edited December 17, 2012 by Frosty039

[Summer Sun]

Tonight's ECM shows the north has the best chance of seeing something colder this side of Christmas

By t120 the huge high to our east pushes further west which in turn could set up a colder northwesterly wind but it will be short lived

By t144 the mild air wins out

Edited December 17, 2012 by Gavin.

[IDO]

Don't see anything cold on the GFS ensembles in the south for Christmas:

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=12&ville=Londres&runpara=0

Though a cool down from the milder previous few days (22nd to 24th). Around 0c uppers on the 25th (very little scatter). The mean bounces along the 0c through to the end of FI; very zonal from there. The mean surface temps suggest about average values for south of Birmingham:

http://wxmaps.org/pix/temp4.html

I am assuming that posters who are looking for that easterly believe that if we get it, it will be sustained? I have seen GFS play around in the last 12-16 runs with numerous solutions and none have the block to our east winning. All I see is it delayed, slowing down the inevitable westerly approach. I suppose if the delay is long enough there could be a sea change that pushes the block back west? That is, amplification upstream, Arctic High, sinking south of the jet, etc? We have had these to varying degrees in many of the runs but there is still little change in the synoptic output!

I suppose this is a very unusual scenario and we should take heed of the experience of members like the OldMetMan and others who have experience and know that things are maybe not all what they seem.

[nick sussex]

Given the margins here it could either be a damp squib or snowy surprise.

The models at this range even if say they were right in terms of pattern wont be accurately modelling the boundary between rain/snow.

So a hundred miles either way is going to prove pivotal to the weather on the ground.

[Snowmad79]

Tonight's ECM shows the north has the best chance of seeing something colder this side of Christmas

By t120 the huge high to our east pushes further west which in turn could set up a colder northwesterly wind but it will be short lived

By t144 the mild air wins out

The only way you would get a cold NWerly at 120 with High backing west is if winds somehow reversed around that HP lol

[chris55]

Don't see anything cold on the GFS ensembles in the south for Christmas:

http://modeles.meteo...ndres&runpara=0

I am assuming that posters who are looking for that easterly believe that if we get it, it will be sustained? I have seen GFS play around in the last 12-16 runs with numerous solutions and none have the block to our east winning. All I see is it delayed, slowing down the inevitable westerly approach. I suppose if the delay is long enough there could be a sea change that pushes the block back west? That is, amplification upstream, Arctic High, sinking south of the jet, etc? We have had these to varying degrees in many of the runs but there is still little change in the synoptic output!

I suppose this is a very unusual scenario and we should take heed of the experience of members like the OldMetMan and others who have experience and know that things are maybe not all what they seem.

Thats a good post, and realistic. Taking the NWP at face value there is little of interest regarding colder weather for the xmas period. But with the changes in the 96-144 period and the ECM ensembles there is still enough up in the air to allow a little speculation on the upcoming pattern.

Edited December 17, 2012 by chris55

[swfc]

Struggling to see why the ecm has gone so scatty since this mornings run ie the low at 144 -168 hrs.Also ukmo and ecm look miles apart!!!

[Matty M]

We are still hung on this one!

Changes as early as T72hrs are possible as the timing of the wave developments are uncertain.

An interesting few days ahead with cold air perilously close to the northeast

[nick sussex]

Yes it looks like a downgrade compared to the ukmo, turning wet, windy and milder from midweek onwards for all areas.

And that's what bbc news 24 just said, milder and wet from midweek, no mention of any cold anywhere!

Thats strange considering the operational outputs, both the UKMO and even the ECM would provide some snow chances for Scotland and ne England.

Either they've already ditched their operational outputs because of the ensembles or they meant to say milder and wet from midweek till Friday!

It wasn't Darren Bett by any chance? !!!

[Matty M]

192hrs ECM is Blooming amazing, where did that little surprise come from

What's that up north bursting through the PV!

Edited December 17, 2012 by Matty M

[Frosty.]

Given the margins here it could either be a damp squib or snowy surprise.

Damp squib since news 24 said turning milder, wet and windy from midweek onwards, no mention of any cold even in the far northeast, so it's not looking good for snow anywhere now, have to say though that the 850's look rather cold on ecm 12z compared to what the weather man just said, so the models must be wrong?

[chris55]

Anyone any clearer on the eventual outcome????

[Frosty.]

It wasn't Darren Bett by any chance? !!!

Nope it wasn't the mild ramper darren bett or the other one, peter gibbs, can't remember his name but there was no mention of cold or snow for any part of the uk, just turning wet, windy and milder for all areas, very bullish he was too.

[IDO]

Where is the Arctic High going?