Model Output Discussion - Staying cold into the new year

[Speedbird]

4 minutes ago, bluearmy said:

this is our issue for next weeks easterly ... that milder air thrown up into the Baltic 
 

there's a 1,200 mile journey before that even reaches our shores - plenty of opportunity for it to change between now and then

[I remember Atlantic 252]

2 minutes ago, Speedbird said:

there's a 1,200 mile journey before that even reaches our shores - plenty of opportunity for it to change between now and then

hope so, but this is not going way of UKMO for Wednesday

[Hotspur62]

5 minutes ago, bluearmy said:

this is our issue for next weeks easterly ... that milder air thrown up into the Baltic 
 

Yes I have been looking at the temperatures in Estonia Latvia and Lithuania and they don’t really start dropping till next Wednesday looking at 3 or 4 different weather apps.Very frustrating as at this time of year that area averages -1 to -3 temperatures but for next 5/6 days the temps are zero to plus 3!!Makes a huge difference!!even if they were to drop 1 degree say by Sunday it could have big implications for us.

[Battleground Snow]

Pretty similar run from the GFS so far, would like developing high in Greenland to shift a little east for a better outcome in FI than the 00z run

 

[carinthian]

22 hours ago, carinthian said:

I have a bit of an update from the Central European team of forecasting experts. Their charts currently show a strong alignment to the UKMO at 144t.  Looking a head for period 144t -240 they expect a two pronged attack to affect the British Isles during the first third of January. Firstly ,pressure falls in Biscay expected to transfer towards Low Countries with increasing tightening of the isobar flow ( easterly component ) especially for Southern England. Secondly, later in the period pressure falls from the North with a NEly becoming more widespread. The snow computer outer parameter results flags up a increasing snow risk for SE England during this period, marginal at first but becoming more definite later in the period ( possible due to a much colder source of Scandinavian getting established ). Hope this helps.

C

A further up-date follow on from the above post. The chart below from UKMO at 144t is on the cusp of something special in the time span 168t-240t. The current view over here is for the low shown near Iceland to sink and form a general low pressure circulation over Europe with its core just to the SE of the UK. This will allow a much cold upper air mass feed  get established sourced from Scandinavia and hence the snow risk increases.

C

[ALL ABOARD]

After 144 on the GFS watch how quickly that small band of minus 8 uppers begins to expand. 

Continental cooling in full effect. 

Longer it continues the more cold pools will develop even without a direct feed, also the models will not pick up on this until closer to the timescale. 

[MKN]

GFS 06z showing a little bit of a promise with the direct easterly flow which is sourced from relatively milder air changing to drag in some colder air out of France for a time increasing the risk of snow

[ALL ABOARD]

By 174 

 

The artic floodgates are open... 

But the continent is cooling itself. 

-12s evident. 

 

[sheikhy]

Just now, MKN said:

GFS 06z showing a little bit of a promise with the direct easterly flow which is sourced from relatively milder air changing to drag in some colder air out of France for a time increasing the risk of snow

Yup main thing is its better than ecm for that 72 to 144 hour timeframe!!

[Griff]

GFSP 144

 

[I remember Atlantic 252]

2 minutes ago, MKN said:

GFS 06z showing a little bit of a promise with the direct easterly flow which is sourced from relatively milder air changing to drag in some colder air out of France for a time increasing the risk of snow

Aye, temps perhaps a notch down, still rain and sleet but perhaps more sleet than rain, unlike 00Z

[Griff]

Definitely would prefer a colder correction to the east in FI... 

[The Enforcer]

3 hours ago, Ali1977 said:

What on earth are you doing to us ECM, day 10 is an absolute beauty!!

If this happens I think we should be thinking about the word HISTORIC!! However it is day 10, so let’s keep that in mind.

 

Closer to the here and now , this could produce some snow off the North Sea - -6/-8 uppers , or are the other perimeters not conducive??

Dew point and DAM look ok.

 

 

2 hours ago, Tim Bland said:

A better ECM for snow prospects this morning. Still some rain from the east Mon / Tues, but by Weds it’s turning to snow over the hills and by Friday there’s snow coming from the north.   Still hopeful for another upgrade to lower those temps enough to make early next week a snow fest for the east...

Hold on a minute, if the air has got sufficiently cold/dry by the beginning of next week to introduce colder 850 temperatures than previously forecast and negative dew points, why is the precipitation throughout next week still mostly rain?

Edited December 31, 2020 by The Enforcer

[sheikhy]

I think we gona see upgrades on the 12z in terms of 850s!!!!love how this gfs develops its own cold pool across us from 132 hours!!!!

[Battleground Snow]

4 minutes ago, carinthian said:

A further up-date follow on from the above post. The chart below from UKMO at 144t is on the cusp of something special in the time span 168t-240t. The current view over here is for the low shown near Iceland to sink and form a general low pressure circulation over Europe with its core just to the SE of the UK. This will allow a much cold upper air mass feed  get established sourced from Scandinavia and hence the snow risk increases.

C

The GFS is now showing the low drop directly through the UK, a minor south east adjustment would be perfect!

Thanks for these updates over the years

 

[Blessed Weather]

A few posts moved over to the Regionals. Please use those threads for discussing chances of snow or current conditions imby. Many thanks.

[ancientsolar]

1 minute ago, Battleground Snow said:

The GFS is now showing the low drop directly through the UK, a minor south east adjustment would be perfect!

Thanks for these updates over the years

 

The way it is, wouldn't it allow to pick up more moisture from the atlantic. A South East tweak may allow colder air but perhaps lessen potential snow fall ? 
 

[Methuselah]

One of my least favoured synoptics (at any time of year!): air from a 'warm' source being progressively cooled from below:

    

From 'Goldilocks' to 'Moldilocks' in one fell swoop!

[bluearmy]

2 minutes ago, The Enforcer said:

 

Hold on a minute, if the air has got sufficiently cold/dry by the beginning of next week to introduce negative dew points, why is the precipitation still mostly rain?

The rain arrives with the positive Dp’s. Any convective showers early next week ahead of the rain could well be of a wintry nature and even potentially snowy. But at the moment, the arrival of the proper precip is in conjunction with some less cold air both aloft and at the surface. As others have said, this could change but not what the models currently show ... we can’t see what Ukmo is hiding beyond heights and uppers ! 

[Griff]

3 minutes ago, sheikhy said:

I think we gona see upgrades on the 12z in terms of 850s!!!!love how this gfs develops its own cold pool across us from 132 hours!!!!

Similarly GFSP looking east, but will the very cold from the north end up too far west again? 

Atlantic looks shut off on both models. 

 

[Battleground Snow]

1 minute ago, ancientsolar said:

The way it is, wouldn't it allow to pick up more moisture from the atlantic. A South East tweak may allow colder air but perhaps lessen potential snow fall ? 
 

Yes it is a tight balancing act as usual, but the wind would turn more east or north east after the low passed and improve our chances later on

[Vikos]

1 minute ago, Griff said:

Similarly GFSP looking east, but will the very cold from the north end up too far west again? 

Atlantic looks shut off on both models. 

 

Classic artic outbreak if it strikes a bit more to the east. But that are just silly details

[IDO]

The gfs op 06z closer to the mean with regard to where the ridge and trough sits and avoids the ridge breaking as the 0z did:

06z> 0z mean>

So the op moving towards the ecm, which looks better up to d10?

[Harsh Climate]

Well I think the GFs 6z is a big upgrade regarding the easterly for North east England and Yorkshire. 36-48 hour window monday ~ tuesday upers of -7 with occasional -8. Would just tip the balance in our favour with some decent accumulations! Yes milder uppers on te way wednesday but would only be short lived.

[Froze were the Days]

3 hours ago, mountain shadow said:

Cold and getting colder, much colder.

If I had a pound for every time I've read that!...fact is cold getting slightly less cold with a possibility of it getting colder again is closer to the mark, looking at Day 9/10...although both 0Z GFS/ECM are not far apart on their runs I wonder how long it will stay like that?