The hunt for cold - Model discussion (late November)

[shaky]

33 minutes ago, Steve Murr said:

Yes

The GFS moves the pattern or rather the 'continental air mass' further west - however the front still squeezes out the cold air -

However we have on the GFS gone from a straight SSW flow to a direct southerly- still 90 hours to go & every chance of a bit of undercutting- bearing in mind the 00z 72 had -2c uppers in London, now down to -6 on the same timestamp...

If its of any consolation arpege is further west at just 48 hours again!!so slight upgrade for the weekend on the gfs 06z and now arpege looks like goin some way!

Actually a noticeable push west and upgrade at 72 hours!!

Edited December 11, 2018 by shaky

[Yarmy]

5 minutes ago, Daniel Smith said:

GLOSEA update continues the blocked theme Jan-March

That looks fantastic. What could possibly go wrong? 

 

[swfc]

5 minutes ago, Yarmy said:

That looks fantastic. What could possibly go wrong? 

 

A dog breaking wind in Alaska and crippling the flow!!!!!

[aitchbomb]

14 minutes ago, ALL ABOARD said:

Glosea update. 

Surely there’s lots of room on that chart for some good easterlies.

[Met4Cast]

1 minute ago, aitchbomb said:

Surely there’s lots of room on that chart for some good easterlies.

Because it's a 3 month ensemble blend chart it doesn't really tell the whole picture - You could have an entire month of intense blocking and then be stuck in no-mans land for 2 months and still get a chart like the one above.

Though it's certainly encouraging! GLOSEA is tied heavily into Stratospheric forecasts too I believe, it's the model MO focus heavily on when doing contingency based forecasts, so encouraging nonetheless!

[weirpig]

1 minute ago, Daniel Smith said:

Because it's a 3 month ensemble blend chart it doesn't really tell the whole picture - You could have an entire month of intense blocking and then be stuck in no-mans land for 2 months and still get a chart like the one above.

Though it's certainly encouraging! GLOSEA is tied heavily into Stratospheric forecasts too I believe, it's the model MO focus heavily on when doing contingency based forecasts, so encouraging nonetheless!

Lets hope it verifies better than the one a couple of years back  with its promise of a cold winter with winds from the North East  

[Met4Cast]

Just now, weirpig said:

Lets hope it verifies better than the one a couple of years back  with its promise of a cold winter with winds from the North East  

ECM seasonal forecast is along similar lines to GLOSEA

So certainly support there - Does tie in with what the experts (GP etc) on here are suggesting too!

 

[frosty ground]

Almost some consistency from the GFs with a ridge being thrown up at this range, looking north the christmas period could be colder than the 0z run.

[terrier]

14 minutes ago, Yarmy said:

That looks fantastic. What could possibly go wrong? 

 

Well we live in the U.K. right next to the Atlantic Ocean. So if it can go wrong 9 times out of 10 it will do. It’s the law of sod in this country

[Methuselah]

Is that a nascent Griceland HP I see? Or a precursor to yet another near miss:

[SMU]

Yes & the 06Z FV3 making changes - again highlighting that a lot can change in 90 hours

06z on the left

What I am highlighting is if we have more jet energy breaking away SE it wont necessarily adjust the PPN belt but will influence the curvature of the isolines from SW to S then maybe to SE holding the cold air in place - Remember the GFS has been lifting out -3 ish air from the SE, now the -8c line is there its getting a lot harder !

[BlueHedgehog074]

4 minutes ago, Daniel Smith said:

Because it's a 3 month ensemble blend chart it doesn't really tell the whole picture - You could have an entire month of intense blocking and then be stuck in no-mans land for 2 months and still get a chart like the one above.

Though it's certainly encouraging! GLOSEA is tied heavily into Stratospheric forecasts too I believe, it's the model MO focus heavily on when doing contingency based forecasts, so encouraging nonetheless!

Both those GLOSEA and ECMWF seasonable forecast charts definitely a lot more preferable than having high (positive) anomalies to our South and Low (negative) anomalies to our North. 

Could imagine some of the disappointment in here that may likely happen if that was the case. Maybe the prams getting thrown about as well as the toys. 

Some nice looking charts anyway.  

[ICE COLD]

4 minutes ago, frosty ground said:

Almost some consistency from the GFs with a ridge being thrown up at this range, looking north the christmas period could be colder than the 0z run.

Yep it’s getting there again . A nice cold Christmas Day .

[SMU]

24 minutes ago, shaky said:

If its of any consolation arpege is further west at just 48 hours again!!so slight upgrade for the weekend on the gfs 06z and now arpege looks like goin some way!

Actually a noticeable push west and upgrade at 72 hours!!

Yes saw that - Easterly is flatter which is good...

 

[Iceaxecrampon]

Windermere hunt. 

Temps on the downward 

[Purga]

GFS 06z still carrying the Xmas baton

There'll be more of these scenarios to follow with a NH profile like this on offer

[Singularity]

Not of the question that the secondary low causing problems this weekend on the morning runs could be adjusted south sufficiently that it can't make the trip NE and has to cut east through S UK instead. Not something I'd bet on though; we're getting a bit close to the time now.

Longer-term, I so wish the modelling had a better handle on the recycling of the Nino tropical cycle as at the moment they just have a fairly weak effort during the next 7 days before giving up and conjuring up a La Nina cycle against all sensibility, which renders the modelling beyond day 8 even less meaningful than usual. There will generally be too much westerly motion in the Atlantic sector, and those runs that do achieve HLB are likely doing so via routes that won't be seen in reality.

 

All we can really say with much certainty is that the festive week will see the tropospheric support for N. Atlantic momentum become minimal, leaving us looking at the stratospheric vortex displacement and hoping that it can't connect to the troposphere sufficiently to drive overpowering Atlantic cyclogenesis regardless. This being why we could do with another bout of wave-2 activity to totally take the organised (even if less than usual) form of the polar vortex form out of the equation. I'm starting to wonder if we can really achieve that this side of New Year - but on the other hand, the models never cease to amaze me with their capacity to be late catching on.

[Methuselah]

So plenty of cold air around, at the 06Z's finishing line...And, there, stuck firmly in the middle is us!

  00Z ensemble for scatter analysis: 

[snowangel32]

44 minutes ago, Daniel Smith said:

GLOSEA update continues the blocked theme Jan-March

That looks blocked and surely even the UK cant mess that up.

[Met4Cast]

6z remarkably similar to the EC46 actually. Heights raise in the Atlantic behind an area of low pressure pulling colder air in over the UK

But the energy coming out of Canada is too strong and pushes the heigh Eastwards bringing a return to milder weather

EC46 shows transient highs exactly like this, maybe we'll get lucky and the cold portion of the high will coincide with Christmas day.

[snowking]

50 minutes ago, Daniel Smith said:

GLOSEA update continues the blocked theme Jan-March

If I'm going to be purposely picky and a little bit obnoxious towards the models.....the only thing I would comment on is that the low MSLP anomaly is a little further North than one would like in an absolutely perfect world. Some would argue that this throws plenty of opportunity for precipitation into the mix....others would argue that it has just the faintest of tinges of the risk of a more west-based -NAO pattern to it....

But I caveat all of the above with the fact that this is a three month average anomaly, and with that sort of pattern, should it prove to be correct, there will be more than enough opportunity for the UK to join in the fun - and this is actually more in line with my thoughts for the coming months than the ECM seasonal projection in terms of where the core of the higher anomalies may sit

[Jonathan Rhodri Roberts]

We're doing a charity walk up Pen y Fan Brecon this weekend and snow is in the forecast as well as rain along with thundery showers but also some sunshine, for us it'll definitely be the coldest weather we've seen since March  

Edited December 11, 2018 by Jonathan Rhodri Roberts

[carinthian]

4 hours ago, carinthian said:

Morning all. Thought you might like these pictures taken in the village last night. 50cm snowfall ! Interesting charts from the models this morning with a bit of a colder upgrade. Looking at the UKMO fax chart , a cold block still in place for Friday with little progress of the front out of Ireland. Think Saturday could be an interest day as the fronts start to push into the cold air ( transient snow for quite a few ) if the current model outputs hold but I think beyond 96 t I-144t is open to uncertainty. Should get an update later from over here as regards to the colder spell to evolve in the 10-15 days ( as indicated in the above post ). 

C 

Suns come out. Sparkling day now, deep snow cover and current temp of -5c. Just a few skiers today enjoying the fantastic weather and scenery in the mountains. A bit of an update from over here. Still not 100% sure how things are going to evolve this coming weekend regarding to the British Isles. Model still keeps showing a slight westward correction on each 24 hourly run output. Longer term charts at day 10 still shows a low over the British Isles starting to slowly sink into Europe and height rises to follow towards the NW. By day 15 some very cold air develops ,especially over Northeast Europe. UK looks cold during this period with snow risk more likely over the continent but still too far out to forecast ,but the trend is there. Hope this helps.

c

Edited December 11, 2018 by carinthian

[snowangel32]

So the picture starts to become a little more clearer. The Snowline for the weekend looks to to be  Scotland, East coast and london area. Obviously high ground still might see a few flakes in the west before the mild air returns.  lead up to Xmas shows a potential ridge building but the placement of that is still unknown with so much going on expect Snowy Nirvana charts but dont get sucked in just yet theres alot to be resolved. Also those in the east throw some snowballs to the west so we can see some snow. Thankyou.

Edited December 11, 2018 by snowangel32

[shaky]

30 minutes ago, Steve Murr said:

Yes & the 06Z FV3 making changes - again highlighting that a lot can change in 90 hours

06z on the left

What I am highlighting is if we have more jet energy breaking away SE it wont necessarily adjust the PPN belt but will influence the curvature of the isolines from SW to S then maybe to SE holding the cold air in place - Remember the GFS has been lifting out -3 ish air from the SE, now the -8c line is there its getting a lot harder !

Yup and to add the euro4 model is further west at 48 hours with much colder uppers than gfs at the same time weird that!!gfs has -4 but euro4 has close to -8!!