Model output discussion - cold spell approaching?

[Mike Poole]

1 minute ago, Frosty Winter said:

Please just be right.

 

Where did that come from?  LOL!  So much going on at the moment that you cant keep your eye on all timescales and models at once!

[Kasim Awan]

Just now, feb1991blizzard said:

It looks like they are going to phase at 150 but not sure it matters by then, the WAA is already in full swing.

Unfortunately on this run the phasing has prevented a clean retrogression north. WAA & amplification is achieved, which I think it will even if the phasing occurs, just let optimal with the stronger Iberian high. 

[nick sussex]

Phasing calamity on the GFS 18 hrs run .

This adds a huge hurdle into getting the cold se .

[DEYS(Kent)]

This has been apparent for days..

[Allseasons-Si]

Not to be taken as gospel...,but that is an improvement on the 12z.

 

[Weathizard]

Of course they phase Bugger off GFS, I’ll take the ECM over it at day 7 all day

 

[feb1991blizzard]

Just now, Kasim Awan said:

Unfortunately on this run the phasing has prevented a clean retrogression north. WAA & amplification is achieved, which I think it will even if the phasing occurs, just let optimal with the stronger Iberian high. 

Yes, scrap what ive just said, completely knackered by 168, its going to be worse than most of its previous output thats for sure.

[sheikhy]

Ishhhh dont look at the gfs at 168 hours!!!!!gfs p follow the op?!!!

[Kasim Awan]

ECM is favoured when dealing with phasing energy of lows. So it is possible that the GFS switches towards the ECM / GEM solution tomorrow, which of course prevents phasing and allows a much stronger retrogression & cold blast. Again, not saying this is a guarantee. I'll make the comment of saying "I hope" it does because I love a good cold, snowy spell as much as the next person on here.

Edited January 11, 2021 by Kasim Awan

[warrenb]

It is simple. If they phase then the strength is going into the northern arm of the jet and the high will topple. No phasing and the low follows the southern arm as a runner under the high

[Griff]

1 minute ago, sheikhy said:

Ishhhh dont look at the gfs at 168 hours!!!!!gfs p follow the op?!!!

GFSP might do better 

[chionomaniac]

12 minutes ago, WINTRY WALES said:

Hi chino 

Great update....if all comes together are you anticipating a countrywide severe spell here...or just the northern half that the met are hinting towards??

That to me is the more precise trop Synoptics following the disruption that is more difficult to be sure of.  Hence one can say that blocking around Greenland is likely, but the southward extent of cold air on its eastward flank is impossible to predict. As in the last spell, I look at the 500hPa pattern first, then look at the surface level Synoptics closer to the time. For those who have had days of cold rain, from the last synoptic pattern have been really really unluckly. Same as being 1 number out with all your lottery numbers, or the scratch card after yours hits the jackpot. It happens. No point in looking back, or assuming that will happen again.

[Weathizard]

Blimey, GFS is stone cold sober, pubs must be locked down wherever it lives

[nick sussex]

This evolution unfortunately is possible if you get this early phasing .

All the se momentum to the cold stops.  These phasing issues will remain unless you get the ECM type evolution which is much cleaner with a large gap between the low heading se and the low near the Azores .

[Mike Poole]

GFS // at T156

This looks like a very good run coming up.  

Edit T174, nope it has phased the lows, may come good again in FI though...

Edited January 11, 2021 by Mike Poole

[bobbydog]

Just now, nick sussex said:

This evolution unfortunately is possible if you get this early phasing .

All the se momentum to the cold stops.  These phasing issues will remain unless you get the ECM type evolution which is much cleaner with a large gap between the low heading se and the low near the Azores .

 

[Allseasons-Si]

We await!!!,...it actually gets the cold in quicker but the angle of attack is a bit suspect.

 

[chionomaniac]

18ZGFS is just another variation on the same pattern.  No more no less. When the pattern completely changes then be concerned.

[MOF]

12 minutes ago, Allseasons-si said:

Not to be taken as gospel...,but that is an improvement on the 12z.

 

Needs to come West....please....

[CSC]

18 minutes ago, Kasim Awan said:

Lol, we're in a colder than average month mate. We're not used to it but given these temps running 2-3C below normal these surprises could happen. 

I know mate! I just mean I’ve been weather watching for a few years now and have not seen something like this. So many changes at so many times!

[Weathizard]

Can’t see anything from the Para, heights over Europe and too our south, very poor over GFS and para it must be said.

[sheikhy]

Arpege 18z snow still on!!same as the 12z down to the tee

[Allseasons-Si]

1 minute ago, chionomaniac said:

18ZGFS is just another variation on the same pattern.  No more no less. When the pattern completely changes then be concerned.

Yes Ed,...totally agree with this

this one could be interesting with that ESB runner heading east under the block.

[Kasim Awan]

3 minutes ago, chionomaniac said:

18ZGFS is just another variation on the same pattern.  No more no less. When the pattern completely changes then be concerned.

That variation leading to quite starkly different surface conditions though. Ultimately need the GFS to come on board with the optimal shortwave activity early tomorrow otherwise, unfortunately, a switch to the GFS phasing solution is looking increasingly likely.

[Griff]

1 minute ago, Weathizard said:

Can’t see anything from the Para, heights over Europe and too our south, very poor over GFS and para it must be said.

Maybe... Wait for it...