Model output discussion - cold spell approaching?

[Frank Trough]

1 minute ago, Tim Bland said:

Para is a snow fest for everyone...especially the south! 

except Bournemouth of course

[Tim Bland]

1 minute ago, Certain kind of fool said:

except Bournemouth of course

I wouldn’t take these charts literately at this stage but there is a risk of occasional snow right down to the south coast..

[sheikhy]

Control good at 168 hours!!mean looks good!!

[georgiedre]

2 minutes ago, Certain kind of fool said:

except Bournemouth of course

What's more shocking is it never gives snowfall for Ireland much.. don't know why 

[ALL ABOARD]

1 minute ago, sheikhy said:

Control good at 168 hours!!mean looks good!!

Mean looks awesome. 

You can see the increased heights towards Greenland and also the separation of the low with it being below the high. 

 

[Notty]

If it was 15th Jan, the period after 19th would be an absolute nightmare for forecasters going on the model shenanigins at the moment

[carinthian]

4 hours ago, carinthian said:

Morning all, lets hope that secondary wave moves through and on time unhindered to release that mass of cold Arctic Air. What can go wrong ? Would like to see the UKMO run at 144t having the potential trigger low a bit further east. However, even before we get there , oh what a messy picture over the coming days into the weekend. Stalling troughs could produce a lot of rain and even snowfall. I think its down  to a matter of now forecasting with short term models and an expert eye coming to the fore as so to speak.

 C

Ok, I have just been picking the thoughts of the team over here. Is this cold Arctic flow coming? I ask  Yes 60/40 probable. Complications in getting there ? Plenty  is the answer. The problems regarding swings in the models and timing to access real cold is partly due to uncertainty in the near time. Their own thoughts now indicate that troughing over The British Isles may start to become more acute over the coming days caused by stalling of weather systems/ fronts against the cold block just to the east. Possible heading for some kind of undercut development.  Changes by the hour rather than the days , so best  not look too far ahead at this particular time. Hope this helps a little.

 C

Edited January 12, 2021 by carinthian

[DanDorsetUK]

5 minutes ago, Certain kind of fool said:

except Bournemouth of course

I'm also in Poole wouldn't worry to much at this stage. From that position would only be a matter of time anyway. I'm also expecting a bigger push south of the main lobe than currently indicated anyway with enhanced warming and downwelling coming up.

[That ECM]

Strong signal here imo. I’ll let others worry about detail.

[Battleground Snow]

3 minutes ago, ALL ABOARD said:

Mean looks awesome. 

You can see the increased heights towards Greenland and also the separation of the low with it being below the high. 

 

That's a very good improvement compared to earlier, it should show up in the graph form as less scatter now.... Confidence is rising we will get the initial Greenland ridge, but maybe just wait until the 12z until we can be sure

[Malcolm Edwards]

9 minutes ago, Certain kind of fool said:

except Bournemouth of course

And Costa Del Marazion 

 

[Methuselah]

Well, it might well look like a developing 'West-based NAO', but does that always matter: the HP is plenty strong enough to push the jet stream away to the south, and with that deep cold block over Europe, a series of 'channel-runners' would be a good bet? All out in La La Land anyway!

    

Does anyone know what the NAO was, in 1947? Because whatever it was, it was kind enough to allow a succession of snow-making Atlantic depressions to cross the very south of the UK --  for an entire month!

[Weathizard]

Mean is an improvement on the 0z, it could be a case of patience being a virtue, at present it seems like true cold isn’t really coming towards a reliable timeframe but we’d be exceptionally unfortunate not to get cold soon after this

[Kentish Snowman in Yorks]

13 minutes ago, Atmogenic said:

Waiting till the 18th for people to start posting charts another week away like it has been since the start of december 

The real cold has been forecast for around 20 January give or take a day for days and days.

If we get to the 18th and the cold is still over a week away your comment is justified.

I actually think this forecast cold spell has been ticking down quite nicely. 

Only around a week away now so we should start firming up on the details over the next 2 or 3 days ?

[Matt H]

57 minutes ago, warrenb said:

Heights over Europe again, if that is there, the low (trough) that is over us cannot move through, either pushing the high to the west further west, or becoming stationary. As we were a few weeks back with the trough stuck over us.

 

45 minutes ago, warrenb said:

Not really positive, the initial amplification is too far west, meaning with the reversal going on at the moment it can only go further west, with the trough over us or just to the east, this aids the push.

Can you come back before the 12z runs roll out to use some more of this reverse psychology on the models?

[legritter]

2 minutes ago, General Cluster said:

Well, it might well look like a developing 'West-based NAO', but does that always matter: the HP is plenty strong enough to push the jet stream away to the south, and with that deep cold block over Europe, a series of 'channel-runners' would be a good bet? All out in La La Land anyway!

    

Does anyone know what the NAO was, in 1947? Because whatever it was, it was kind enough to allow a succession of snow-making Atlantic depressions to cross the very south of the UK --  for an entire month!

Not sure about the NAO ,but plenty of v low 850s ,and trough s  a plenty ,my late uncle retired met office, told me that features popped up at very short notice ,6cm snow per hour for 4hrs quite often, and crystal clear sky at 10pm only to get up at 7am to 15cm snow ,that was the bristol area ,biggest fall of snow 3/4 march roughly ,we can only hope but we do have a ticket cheers gang .

[Tim Bland]

GFS on the warm side for 19-20th looks like para could be more in the money with a quicker route to cold (less shortwave dramas) 

[daz_4]

6 minutes ago, Tim Bland said:

GFS on the warm side for 19-20th looks like para could be more in the money with a quicker route to cold (less shortwave dramas) 

Well Para 6z actually takes much longer to pull cold air south and then blows it away in like 24 hours.

[nick sussex]

Encouraging run from the GFS 06 hrs run at least with less phasing issues but you’d still like a se wards correction .

Theres no chance of this pattern ending up too far east but there is of this turning into a west based negative NAO .

In locked in cold pattens any west based negative NAO is normally short lived , although the cross polar flow looks great from a NH perspective it doesn’t help if that’s too far west .

Anyway that’s well into FI , the main thing is to overcome those earlier phasing hurdles .

[sebastiaan1973]

17 minutes ago, Weathizard said:

Mean is an improvement on the 0z, it could be a case of patience being a virtue, at present it seems like true cold isn’t really coming towards a reliable timeframe but we’d be exceptionally unfortunate not to get cold soon after this

I'm not sure about that the cold air moves from the Arctic to Iceland, a westerly movement, it should (my point of view) southwards. The area of high pressure is to much to the west.

[syed2878]

4 hours ago, Mucka said:

It may not be the insanely cold but it looks like snowy day 10 chart.

If the low phased a few hours later then we would have the vary cold uppers pushing S over the UK instead of SW into the Atlantic.

We should really be celebrating the synoptic and getting past the danger phase as the details are going to change run to run.

just get me to 120/144 with no phasing to our W and I will take my cold, very cold, extremely cold or brutally cold medicine from there. 

 I think currently the BBC going along with the ECMF Outlook in their long range monthly outlook they are saying that the main cold will be in the east and may miss us how ever they do say that with caution I do like the look of today’s ECMF though. Just out of interest what is the ECMWF 46 showing today? Do any of you have this month glosea update?

[Cymro]

I have been a member of these forums since 2006 and not once can I recall such a prolonged and fascinating period of model watching. Truly fantastic! 

Every year there are new buzzwords, concerns and themes that absorb strongly into the discussion. This year I think all fingers can firmly be pointed at the words ‘West based Negative NAO’  Never has a phrase been so prominent! 

I think the concerns of a west based negative NAO will be reassured over the coming days! 

Bon voyage! 

 

[Cloud 10]

Cold air well established on GEFS day 10 () mean.

 

[That ECM]

T240 mean.

[Matt H]

GEFS 06z ensembles look very good beyond the 21st with a clear trend for colder weather now. Average goes down to around -5C but many runs also go colder than this.

Edited January 12, 2021 by Frosty Winter