Model Output Discussion - 18z - 6th December onward

[January Snowstorm]

Block is in a slightly better position to withstand an Atlantic attack, surely you would think the energy would go under. I'm sure it will !

Is the block not too far North though ??

A bit like last week

[bradymk]

Might not look it at face value but im liking the Gfs FI here, a few tweaks and some good charts. Without worrying about longer term, we still have potentially a week of very cold weather first, but some christmas cold would be a bonus Matthew

[Rob K]

Is the block not too far North though ??

A bit like last week

North is good. It means pressure is lower over the UK and stops the block sinking. If the energy went over the top then it would be game over for cold fairly quickly.

[Alex95]

One word of advice though - the +120 frame onwards often change by a couple of hundred miles, and with high pressure being modelled further north now it wouldn't take much for a Feb 2001 style bust around the +144 time frame. Significant snow from the North East down to Norwich is pretty likely now on Monday night and Tuesday though from the NNE wind. That would actually be better than an E'ly for lying snow in these areas as very cold uppers are less important as the warming effect of the North Sea would be reduced.

If anyone is nervous about next week ,just remember that this could actually just be the first bite at the cherry. Looking at the strat thread there is the possibility of a cold January too.

Edited December 6, 2012 by Alza

[Snowman.]

If that low went through the channel we could be put straight into a freezer!

[GoonerGregg77]

While cold, very cold air slides it's way across Eastern England early next week, yes we may end up with a narrow northerly with a slight NNE slant, but this is still a great scenario for us. The cold air will be frigid, and with a relatively warm north sea, we will end up with showers of snow, and longer spells at that in a gentle breeze that will feel perishing for our little Island.

Lots want the easterly of all easterlies, but if we can just have patience, I am very confident personally a easterly will evolve and we get what we want. ANYTHING from the east will do! The air mass there is going to be so, so cold, it will do!

I personally believe NE Scotland, NE England E Anglia will do very well out of this, also Kent and eastern parts of Suffolk, Essex etc. I know getting specific is dangerous and can cause disruption litterally to this forum, it's my belief, and can be taken with a very tiny pinch of salt.

We need to get real anyway, were heading for a very cold spell, and the threat of snow! Which is just brilliant this early.

[Ian Brown]

Is the block not too far North though ??

A bit like last week

We could do with it being further South to advect more PPN further West, as things stands at the moment, it's a tortuous process to get the colder uppers to clear Ireland, and by the time that has happened, the Atlantic is threatening.

[Paul T]

Higher risk run (potentially more marginal temps) but fantastic run that could bring serious potential for undercutting.

Shortwaves and lows up the channel have massive potential to bring snow to much of England and Wales with 850s remaining low.

As I say again; get the 850's low and in place, and then bring on Atlantic attacks. A potent mix for Christmas fun.

Happy man.

[PubliusEnigma]

Could be a snow fest for Ireland by T180 !!

[Geordiesnow]

50/50 because of one GFS 18z OP run? I beg to differ. 50/50 would be successive OP runs and a swing in the ensembles. Please think before you post misleading and factually inaccurate comments.

In any case, this 18z run is still good.

It could very well be an accurate comment in future runs though? We should not lose the cold but as JS says, we may lose the easterly element and at this stage, you can't say for certain we will have an easterly flow by Wednesday for example.

We do have to be wary about those shortwaves near Greenland, theres quite a few of them around there, even the ECM shows them but phases them out nicely, GFS 18Z(and to some extent the 12Z) has one coming into play. We only need to go back to the October cold shot how a late developing shortwave entered Greenland which killed heights very quickly and therefore shortening any Northerly shot at the time(although it did deliver snowfall for some admittedly). Of course the end of November potential was getting ruined by shortwaves so I won't be popping any corks out just yet.

Tomorrow morning runs will hopefully tell me whether the GFS 18Z run is perhaps onto something regarding the shortwaves, on a IMBY POV, it may make a difference between a cold sunny day and a day of sunshine and showers.

[Ian Brown]

T192 and snow moving NE, milder air behind.

[bobbydog]

Might not look it at face value but im liking the Gfs FI here, a few tweaks and some good charts. Without worrying about longer term, we still have potentially a week of very cold weather first, but some christmas cold would be a bonus Matthew

i have to agree- look at this-

take away any model bias, add some reality, that could be showing a raging easterly with a channel low!

[Harve]

This is the sort of thing people having been talking about. Easterly;snowy breakdown; reload/retrogression to Greenland:

This is only a snowy breakdown from Inverness northwards. In southern England uppers are 2c in that frame.

[German Sheperd]

i have to agree- look at this-

take away any model bias, add some reality, that could be showing a raging easterly with a channel low!

I like the cut of your Gib Sir!

I was thinking the exact same scenario, I when looked at that chart. Not that I have Scooby Doo, compared with some on here though.

GS.

Edited December 6, 2012 by German Sheperd

[ITSY]

This is only a snowy breakdown from Inverness northwards. In southern England uppers are 2c in that frame.

The snowy breakdown was before then, this is the realignment of the block. ANYWAY, I'm off to bed. Things seem to be shaping up similar to what Ian hinted at on his local BBC forecast. Basically, showery (potentially heavy) snow for some in Eastern regions followed by an attempt to bring in milder air that COULD lead to a snowfest for some. Could be a very interesting period coming up. Night all.

[Snowman.]

While cold, very cold air slides it's way across Eastern England early next week, yes we may end up with a narrow northerly with a slight NNE slant, but this is still a great scenario for us. The cold air will be frigid, and with a relatively warm north sea, we will end up with showers of snow, and longer spells at that in a gentle breeze that will feel perishing for our little Island.

Lots want the easterly of all easterlies, but if we can just have patience, I am very confident personally a easterly will evolve and we get what we want. ANYTHING from the east will do! The air mass there is going to be so, so cold, it will do!

I personally believe NE Scotland, NE England E Anglia will do very well out of this, also Kent and eastern parts of Suffolk, Essex etc. I know getting specific is dangerous and can cause disruption litterally to this forum, it's my belief, and can be taken with a very tiny pinch of salt.

We need to get real anyway, were heading for a very cold spell, and the threat of snow! Which is just brilliant this early.

I feel comforted with this as a NE usually effects the eastern coast and leaves me alone but this usually evolves into a easterly anyway but It might take sometime for that but I reckon come new year we will have a look a simple fresh easterly!

[Weathizard]

FI won't happen don't really understand why people waste their time discussing it because these things will never happen and the GFS to me, although not bad, just keeps overblowing the Atlantic as usual. There will be upgrades within 96-120 timeframe, I'm sure of it.

[Rob K]

Some very enticing solutions showing up in the long range recently. Factor in the GFS tendency to overblow Atlantic depressions and you could see an old fashioned blizzard from the sw quite easily. That would always introduce milder air in places of course but they are the source of the true classic dumps of snow.

Edited December 6, 2012 by Rob K

[Catacol]

This is the sort of thing people having been talking about. Easterly;snowy breakdown; reload/retrogression to Greenland:

Yep - and while these FI charts are pretty much a waste of time in terms of detail the depth of cold forecast to be sitting over Scandinavia by the start of the week here (17th) is frightening. Check the 850s and uppers of -16 creep towards us. It's always a big if... but with even John Holmes touting an extended spell of cold and a dominant pattern of high pressure to the NW or NE it is certainly not beyond the bounds of possibility that some very cold air indeed could make an appearance.

Notice I said "if" and "not beyond the bounds of possibility..." - for about the 4th time tonight I'll wave the "follow the general pattern flag" and say that all is well if you want cold, but details will be impossible to get right at any kind of range in this scenario. Blocking scenarios often throw the models into a hissy fit.

[BARRY]

A channel low is the best way for the SW to get any significant snow fall

[TEITS]

Latest +96 fax chart and that will do nicely for me.

Cold front clearing S with the chance of snow showers developing later on during Monday night in E areas.

[PubliusEnigma]

T192 and snow moving NE, milder air behind.

Still cold in scotland though could see a seriously large fall of snow. Remember that the air over the UK will be frigid so some of the showers behind the

cold front could be of sleet or snow !

[chris55]

Could be a snow fest for Ireland by T180 !!

With embedded cold air and some very cold dewpoints coupled with a SE drawing Low, snow is a major possibility if the Atlantic does attempt a push in later next week.

By far my favourite type of set up...high risk but high reward.

[bobbydog]

I like the cut of your Gib Sir!

I was thinking the exact same scenario, I when looked at that chart. Not that I have Scooby Doo, compared with some on here though.

GS.

a couple of frames on and even nearer the mark!-

thats a flap of a butterfly's wings away from a winter wonderland....

[Ian Brown]

The problem we have is once you have seen the weakening of heights at Northern latitudes - the yellows become the greens - then you are open to Atlantic attack, and that will usually end in what the 18z goes onto show at about T204, the archives shows lots of cold spells ending this way. Of course it may not happen like that, but I think the idea of this particular HP ending up over Greenland is now a fading possibility.