Model output discussion - into Christmas

[Yarmy]

UKMO T168 looks a lot more like the ECM than the GFS 0z or 6z with the ridge building to the west of the UK:

 

 

 

[shaky]

1 minute ago, Yarmy said:

UKMO T168 looks a lot more like the ECM than the GFS 0z or 6z with the ridge building to the west of the UK:

 

 

 

That looks fantastic from a coldies perspective!!surprised steve aint commented on it!!if that high arcs around the uk favourably then an easterly 24 to 48 hours later is not impossible!

[Methuselah]

Only one question remains unanswered: which colour mankini should one choose?

   

[Frosty.]

Not posted since Sunday but this is what I'm hoping for..this is winter isn't it?...I want snow dammit!!!!!!!!❄

[Jordan S]

Wet this afternoon for England and Wales though totals will vary between a few mm's and upto 10-20mm windy too.. 

This rain pushes into northern Ireland and Scotland during this evening and the first part of the night giving some very wet conditions for a time too. 

Its the second batch of rain pushing out of france into southern counties later this evening and overnight that will give the most rainfall of this wet spell for most. 

Some heavy and persistent rainfall for large parts of the England and Wales tonight there's uncertainty with placement of the highest totals but central southern England are most likely to experience the most as much as 15-25mm will likely accumulate widely but a few places seeing potentially around 40mm with flooding problems in places, an area of low pressure will likely form on this front bringing strong winds for southeast England and east anglia with 30-40mph gusts likely later tonight. 

Looking at Christmas day after a lot of uncertainty regarding Christmas models now seem to be firming up more on the big day. Most likely scenario drier and brighter with just a few showers chilly too. 

GFS.. 

Gem.. 

Ecmwf.. 

A little different though with a disturbance shown to drift southeast over the country bringing light rain and a little hill snow to England Wales and northern Ireland but that's uncertain. But high pressure quickly builds right behind it. 

Ukmo.. 

Edited December 19, 2019 by jordan smith

[phil nw.]

Odds on then for a Christmas high near or over the UK.Ok not the most exciting pattern for snow lovers but at least a chance for water levels to drop and maybe some seasonal frosts.

It will be interesting to see where this leads us after and whether the high can at least hold and maybe build from here.

The 00z GFS run was certainly a pressure outlier with wanting rid of it and with the fall off in 2m temperatures this could well signify a cold block ongoing into NY.

Signs in the gefs of the high drifting a little further east later so perhaps a coldish south easterly from a cooling continent as the Atlantic is held at bay. 

 

[weirpig]

Control  having non of the op sillyness

[Weathizard]

Anyone for a New Years BBQ?

[northwestsnow]

41 minutes ago, bluearmy said:

Plenty to keep us interested this morning

we also have some eps clusters which separate a cut off upper ridge away from the Azores base - good direction of travel 

All eyes on the Atlantic sector post Christmas ..

[West is Best]

At some point one of these GFS operational runs is possibly going to take a very different tack. The spread is considerable, with some significantly colder members. The transition point appears to coincide with the synoptic setup around 27/12:

[weirpig]

Direction of travel  going by the GFS 6z  is height rises over or near us  then migrating  around the Scandi  area    The mean suggests  that  the high at this juncture does not allign  for any cold to head our way     though of cause very much subject to change.

[Ali1977]

By day 10 we seem to have a split in the ENS, with versions of these 2 type set ups!! I know which one I hope comes to fruition!! 

 

extreme end of both sets below.

Edited December 19, 2019 by Ali1977

[Anthony Burden]

Will it be short sleeve shirts or overcoats and gloves over the festive season,still no agreement with 

GFS or ECM .I think I know the favourite but favourites do not always win,let’s hope they do this time.

[frosty ground]

52 minutes ago, bluearmy said:

I haven’t read it but with an e qbo arriving, surely we have a better chance of a qtr ??

I honestly don't know but its a month away from happening if indeed it does happen.

[Mucka]

ECM ensembles moving toward cold post Xmas

 

 

Still plenty of scatter though and a long way to go...

Edited December 19, 2019 by Mucka

[Anthony Burden]

Take a look at 2 meter temperature for London and the difference between ECMW and NCP big difference.

[Jeremy Shockey]

I think that most us us would take this for Christmas Day ( above as highlighted by UKMO , ECMW , GEM )  Pretty consistent really at t+144

 

[Man With Beard]

As @bluearmy notes above, some potential cold clusters this morning for the New Year

  

though rather messy, it must be said.

Takeaways are:

- New Year likely to see a respite from wind/rain

- Possibilities of High Pressure either migrating to the north east (cluster 2), or as depicted in the chart for New Year's Day, possibility of regression to the high to the west (cluster 1/3/5) (*NB the contours do not show this on cluster 3, but the colour anomalies, which I believe represent all members within the cluster, suggest this is possible)

A long way from telling if this means cold for the UK, but looking like the PV won't have it all its own way once we get past Christmas.

 

EDIT: just scrolled through the 51 members for New Year's Day - consensus by this time is continuation of a UK high (especially for England/Wales, maybe 40-50% of runs), with the next largest cluster regression the high to the west (20-30%), and then smaller groupings either building a strong high to the east / north east, or continuing with a strong Atlantic influence (perhaps 10%-20% each). So much like the clusters except less emphasis on NE block

Edited December 19, 2019 by Man With Beard

[Methuselah]

On its own, I wouldn't take the GFS Operational run too seriously; it is, though, one of six members clustered at around 10C T850s, around December 31...

    

    

That said, the 2m temperatures, between December 30 and January 1, are clearly outliers.

 

 

[Catacol]

Getting close to the reliable for Xmas Day now....and from these clusters we would be very unfortunate not to see a more blocked day with the distinct chance of frost

and with luck people will take this as a win. Given the signals that were there in the long term for a blocked end of the month this is a good result, with more intrigue to come. 
 

Wind forward to the outer edge of semi reliable forecasting and multiple scenarios remain possible with clusters for the 27th demonstrating the potential for a move towards a cut off high, or alternatively a flattening of the pattern slowly but surely

 

...and yet by New Years Day still a struggle going on between the forcings that are amplifying the pattern and the westerly default climatological tendency in December for a flatter Atlantic, This is all fascinating stuff.

Can we take anything from this? Perhaps. Tendency still for blocking in 2019 to be more prevalent than in some years gone by. Tendency for the jet to set France in the crosshairs.... and generally a less obvious Azores High than we have seen at times in the past. Are we seeing there the impacts of a more active equatorial convection pattern than the models have gripped this year?

Dont let the next 3 days of near constant rain fool you - lots happening and plenty possible...

 

[weirpig]

First up  Icon    Blocked and chilly 

Then ends like this   Frosty and cold 

Edited December 19, 2019 by weirpig

[bluearmy]

1 minute ago, weirpig said:

First up  Icon    Blocked and chilly 

but messy on a uk level come boxing day in a way which is v unlikely to verify

[frosty ground]

Looks like a reasonable evolution to me.

Is it that messy? 

[weirpig]

 

12 minutes ago, bluearmy said:

but messy on a uk level come boxing day in a way which is v unlikely to verify

what?  a chart 7 days away  and it wont verify like that.   

[Catacol]

As a follow up I just went through my various bookmarks and looked at all available data. Got to say I can rarely remember a time of such variability in the longer term. Last year, a winter season that will go down as the moment we got confirmation up close and ugly that all forecasts of whatever type and quality can go bad, we had some relatively clear signals as to progress through January - admittedly towards an end product that failed to produce good surface conditions for the UK - and in other previous years we had some quite good guidance. I remember well the joy of Dec 2010 being tempered by the pretty likely downhill nature of a strong La Niña winter once the peak cold had passed, and so it proved to be. 2012/13 had clear pointers despite the abject misery of that failed easterly though ultimately we got the March 13 cold spell. Most recently there were indicators in Jan 2018 that suggested a late season cold spell was on the cards, and once Feb turned the corner the path ahead grew in clarity.

Right now the medium to long term future looks about as clear as mud. On the positive side for cold are the observational realities in my post above, plus low solar, reasonable SSTs, some quite good looking pre cursor patterns to what might be an SSW and an Atlantic pattern that is consistently stalling around the UK. Lots of rain....but given climatological expectations of vortex weakening a good signal long term. On the other hand we have a generally stagnant GLAAM pattern which makes high lat blocking more difficult, seasonal forecasting consistently holding to a +NAO outlook, a vortex which has recovered pretty well from early season attacks, and an IO standing wave pattern that might continue to subdue MJO activity and impact. It’s a real head scratcher.

And medium range modelling reflects this. Up and down like a yo-yo, clusters chopping and changing, trends hard to spot - or appearing and then fading as per GEFS Euro temps around New Year. I guess the point to this post of thoughtful musing is that I challenge anyone to be able to make an accurate forecast of the next 3-4 weeks. Wide open. The best that can be said - and it holds true for most winter seasons, is that the propensity for blocking will increase the further down the timeline we go purely because the vortex begins to weaken post New Year. We can only wait for some clarity to emerge and meanwhile remain optimistic that such uncertainty can work in favour of cold as much as against it.

Final thought? This JMA week 2 anomaly forecast is seriously good if vortex misery is your thing. Strong precursor pattern to a potential SSW.