Model output discussion - 7th January onwards

[summer blizzard]

4 minutes ago, Lloyds32 said:

So the more experienced members seem to think that Greenland High blocking features can be forgotten, and just the odd Atlantic ridging may bring NW blasts of cold air. This has been seen quite clearly in GFS FI. February now we should be looking too for a different pattern? The hunt certainly goes on...

Not per say. Although we can retain cold without much blocking like Dec 08/Jan09, I would be more focussed on amplifying the Atlantic ridge enough to allow the low near us to sink and build pressure over us, potentially leading to undercutting and worrying about retrogression later.

As GP says though, the CET should be falling from the 16th with the first snow shot around the 20th/21st for the bulk of England.

[Methuselah]

I may well be seeing things, but has the FV3 come online today?

[Glacier Point]

Agree with this Nick, although it's noticeable how much sub-tropical flow we get into the SW Atlantic through days 5-12 which is in line with tropical forcing signals. That, allied to the Euro trough gives a strong below average signal for us care of repeated ridge building in the Atlantic. If we get the cold entrenched, these become self reinforcing for cold.

The impacts of the SSW this time are a lot more nuanced and subtle, but they're clearly having a big impact in the pattern.

Edited January 10, 2019 by Glacier Point

[snowice]

46 minutes ago, Ed Stone said:

My my, what an optimistic start to the day, for a change! Hopefully, within the next couple of days or so, wintry charts will start to appear more generally before Day 10?

I can't wait!

PS: Being both autistic and a SAD-sufferer, early optimism kinda makes my day!

I have never seen so many FI charts been posted  in all the years.unless I see in within 7 days timeline I can't get excited.

Edited January 10, 2019 by snowice

[Summer Sun]

3 minutes ago, Ed Stone said:

I may well be seeing things, but has the FV3 come online today?

It was working yesterday just later than normal

[feb1991blizzard]

9 minutes ago, Glacier Point said:

Blocking features are not necessarily Greenland Highs.Within the context of a deep cold trough across NW Eurpe, you don't need strong blocking features. These are however still potentially on the table for the week 3 period, and would represent the icing on the cake.

We go below average on the 16th, and remain there after.

Absolutely, although i still think stable Northern blocks (not necessarily huge in size though) are a more sure fire way to avoid snow being washed away by mild sectors / being on the wrong side of sliders though and more likely to deliver a long cold spell, i still would rather take my chance with a screaming North Easterly even though in the Western side of the pennines - i am still a -15c upper man although, yes i would swap that if you could guarantee me a fall of 10 inches to 1ft from a slider as long as there is a couple of nights of clear skies afterwards.

[BLAST FROM THE PAST]

46 minutes ago, Selliso said:

Omega?

I think we’ll have a lot of disrupted/ slider troughs in amongst entrenched very cold air..  It’s a slow burner alright but the backing away west of the HP to our SW bit by bit is a continued theme and gathering momentum (displaced PVbut not major HLB this month).  It’s still really in FI but it is moving closer now, UKMO being point of order and we are under way nicely by t144.  So I would like by Sat the UKMO t144 to be showing t96.  If we get consolidation over next few days on that model along with ECM then it’s game on.  Remember we are talking about the phasing in of the cold weather set up with troughing moving/sliding NW/SE with deeper cold to usher in along the line.  FWIW I think the GFSp showing displaced PV lobe in our vicinity and then deflecting Scandi HP wedge is not out of kilter.

 

BFTP

Edited January 10, 2019 by BLAST FROM THE PAST

[shaky]

Slightly flatter across the atlantic on gfs 06z at 144 hours!!

[ICE COLD]

Well I would take the toppling high around the 20th if it leads to an Easterly by the 25th .Obviously it would have to be a proper Beast from the East .

[Jonathan Rhodri Roberts]

10 hours ago, Purga said:

Nice snow event for the south and south west!

Ooh we'd be right on the edge of that area of snow here on the coast of southern Wales shame it's in FI though

[Paul]

If you just have a tweet to post and zero model discussion or your own opinion around it, then please just use the model tweets thread. Second-hand, partial info with no context just serves to muddy the waters when posted in here. 

[bluearmy]

the issue here is the euro low anomoly 

this is the gefs 11-16 mean (geps and eps v similar)

clearly this is a signal that grows as time passes but given how difficult it has been over the years to get a Euro low anomoly to sustain, I think the five day mean is a more reliable tool than posting a chart for end week 2. 

If this chart lands then a toppling or dumbelling  mid Atlantic ridge is sufficient to keep the uk wintry 

however, the word of caution remains related to the euro low anomoly .... how many of these have we actually sustained beyond a couple days during winter over the past decade ??

[mountain shadow]

1 minute ago, bluearmy said:

the issue here is the euro low anomoly 

 

If this chart lands then a toppling or dumbelling  mid Atlantic ridge is sufficient to keep the uk wintry 

 

How does the toppling/dumbelling keep the uk wintry though? Would we not get milder Atlantic being brought into the mix? You would have a kind of snow/rain/snow/rain scenario?

[Glacier Point]

Your challenge Nick answered by another question. How many in that period have had Modki / weak / moderate end Ninos / low solar / coming after strong sustained weakening of the SPV ?

[Ali1977]

This is a big difference between latest GFS and ECM at T168 - I know which one I’d prefer. Let’s see if the GFS really is poor and the ECM should be trusted ahead of it!! Still 8 days away so FI in the current climate maybe. 

I’d love to know which GLOSEA is closest too - UKMO , ECM or GFS at 144!!! 

Edited January 10, 2019 by Ali1977

[northwestsnow]

26 minutes ago, Glacier Point said:

Agree with this Nick, although it's noticeable how much sub-tropical flow we get into the SW Atlantic through days 5-12 which is in line with tropical forcing signals. That, allied to the Euro trough gives a strong below average signal for us care of repeated ridge building in the Atlantic. If we get the cold entrenched, these become self reinforcing for cold.

The impacts of the SSW this time are a lot more nuanced and subtle, but they're clearly having a big impact in the pattern.

Canadian vortex can actually be a positive for us as it can assist preventing a west based -NAO longer term...

[northwestsnow]

6Z looks primed for a decent FI (IMHO)..

[Froze were the Days]

Both GFS 0z models and ecm look rather underwhelming again (yes going to use that word) - ecm has potential post day 10 (not as if we haven't been here before this winter) but that all depends if the energy close to Greenland ceases, but if you like the odd Pm flow the outputs might float your boat!

Edited January 10, 2019 by Froze were the Days

[Weathizard]

I must say I think that piece of vortex (lobe of death) over Greenland is a real issue, there’s too much energy running around the lobe that thwarts any attempt at a ridge, the worrying thing is FI doesn’t always show up these features as it they are hard to pick up, so my worry is the wintry stuff we are after gets keeps getting scuppered as it gets towards high res.

Its a slow burner at the moment, almost like a waiting game really... hopefully the SSW is the ace up our sleeve.

[NO LONGER POSTING]

GFS Atlantic bias coming in? 

[frosty ground]

A Complex picture from the GFS, upper pattern not to disimular from the 0z but the surface pressure is very different

[shaky]

Hmm interesting!!the wedge gets in at 198 hours on gfs!!cold northeast wind setting in aswell!!

[frosty ground]

You can see why an area of high pressure has opened up with an easterly for the UK (transient or otherwise)

 

 

 

[mountain shadow]

Shocking difference between ECM and GFS at a relatively short timeframe....

[karlos1983]

Just now, mountain shadow said:

Shocking difference between ECM and GFS at a relatively short timeframe....

I can't see time stamps? when is that for?