Model output discussion - mid January

[Seasonality]

12 minutes ago, karlos1983 said:

UKMO at 144 Very nice 

Definitely, was thinking the same myself. I'd certainly be backing the UKMO over the GFS at that range, well.... with as much certainty as one could expect from a t+144 chart! GFS  slinking towards UKMO solution with its tail between its legs.

Edited January 30, 2018 by Seasonality

[carinthian]

16 minutes ago, shaky said:

Lovely ukmo at 120 hours!!east north east winds into england!!continues the theme from the 00z!!could be a snow fall across england this weekend!!chances are increasimg!also arpege joins the ukmo party aswell at 84 hours!!

Yep , before we get the NEly into England we have an interesting chart from UKMO for tomorrow. Cold uppers into Northern England, possibly -8c at 850mb for awhile. The fax chart shows a succession of cold fronts/ troughs passing through in the flow. Good chance of seeing some snow tomorrow in this area , even to lower levels.

 C

[Seasonality]

Not bad at 168!

[weirpig]

11 minutes ago, carinthian said:

Yep , before we get the NEly into England we have an interesting chart from UKMO for tomorrow. Cold uppers into Northern England, possibly -8c at 850mb for awhile. The fax chart shows a succession of cold fronts/ troughs passing through in the flow. Good chance of seeing some snow tomorrow in this area , even to lower levels.

 C

Oh  no not the North West!  with the amount of luck they have had this winter i expect then to experience a haboob  rather than snow.

Thats a Haboob  not her.

 

Edited January 30, 2018 by weirpig

[inghams85]

2 minutes ago, Seasonality said:

Not bad at 168!

Absolute battleground this period with disrupting shortwaves from the devilish PV. Cold air in front and behind and 3 days of a building cold pool!

[nick sussex]

This seems to have been a very long few days in terms of the models with so much chopping and changing.

I’d still advise a lot of caution because of the very complex set up. There’s not a large margin of error in terms of the evolution between T96 and T120hrs.

Putting that aside the models do seem to be converging on a more battle ground set up over the UK.

 

[frosty ground]

3 minutes ago, Seasonality said:

Not bad at 168!

Just about to comment on that

[Nick F]

Fascinating model watching at the moment, seeing how the NWP handle the trough disruption this weekend and early next week over Europe, as troughing pushing out from the Canadian vortex tries to push SE into Europe but disrupts. 

Seems the GFS has underestimated this trough disruption and subsequent pressure rises over UK and to the NE and was being too progressive in returning us to a W or NW flow, but is backing away somewhat, even though the NW flow the 12z GFS op does introduce eventually is unusually deeply cold too, with -10C T850 cold pool moving in from the NW. 

UKMO first to pick up on the more blocked signal building this weekend and early next week and is still sailing with it on the 12z ...

Edited January 30, 2018 by Nick F

[Seasonality]

UKMO t+144 850s if you please.

[frosty ground]

2 minutes ago, Seasonality said:

UKMO t+144 850s if you please.

Mild sector already squeezed out....

[weirpig]

1 minute ago, Seasonality said:

UKMO t+144 850s if you please.

Very  Nice  looks like -8  across a swathe of the country  as some have said be nice to see the 168h chart  to see if there is any disruption.  Could be snowy for some.

[nick sussex]

It’s a very unusual set up with cold air to the nw and east.

Could we see snow on the likely frontal boundary through the UK and not just on the eastern flank of that.

This would be extremely rare to have a nw meeting continental air and producing more widespread snow.

Anyway that’s some way out.

[frosty ground]

Hmmmmm Ill take one of those please.

[Seasonality]

Helluva Nw'ly blast at 240.

[carinthian]

14 minutes ago, Nick F said:

Fascinating model watching at the moment, seeing how the NWP handle the trough disruption this weekend and early next week over Europe, as troughing pushing out from the Canadian vortex tries to push SE into Europe but disrupts. 

Seems the GFS has underestimated this trough disruption and subsequent pressure rises over UK and to the NE and was being too progressive in returning us to a W or NW flow, but is backing away somewhat, even though the NW flow the 12z GFS op does introduce eventually is unusually deeply cold too, with -10C T850 cold pool moving in from the NW. 

UKMO first to pick up on the more blocked signal building this weekend and early next week and is still sailing with it on the 12z ...

Yes, Nick I am liking the UKMO runs. Sticking with more of a block and getting closer to the more reliable time span. A very rare chart this one at 144t from UKMO , Pm -8c uppers approaching the NW and Pc -8c (850mb level) into the North Sea. Have seen this before but very rare occurrence . A real squeeze on any mild sector with undercuts of cold air from two different sources and can produce some real significant snow. Think I recall late 60s , this happened a few times. As you say, fascinating model watching at the moment, certainly better than this time last winter ( think )!

C

[Seasonality]

1 minute ago, carinthian said:

Yes, Nick I am liking the UKMO runs. Sticking with more of a block and getting closer to the more reliable time span. A very rare chart this one at 144t from UKMO , Pm -8c uppers approaching the NW and Pc -8c (850mb level) into the North Sea. Have seen this before but very rare occurrence . A real squeeze on any mild sector with undercuts of cold air from two different sources and can produce some real significant snow. Think I recall late 60s , this happened a few times. As you say, fascinating model watching at the moment, certainly better than this time last winter ( think )!

C

Very nice looking chart, like two armies charging towards each other and the point where they clash and do battle is smack bang over the UK.

[andymusic]

gfs 12z looks mighty cold for a good part of it's run

[SMU]

So, the devil is in the detail & once again the GFS in any trough disruption scenario is working back to the UKMO - The UkMeT run being resolute now for 2 days - 

The GFS has been slowly backtracking over the last 36 hours - eradicating the impact of the PV run by run but for many that didn’t matter as the cold was a long way east-

Now the alignment has sharpened up so much the GFS is chasing down the UKMO ( but not quite yet )

As a few have eluded to the UKMOs sharpness sees -8c continental air moving West while a ‘chunk’ of vortex is moving SE - all on a collision course with the UK- the mild wedge being squeezed out meaning somewhere could get some good snow- not exclusive to the North-

Still early days but things looking pretty cold throughout the weekend! 

Think of the UKMO as wedges- we have a wedge of weak heights to the NE, A wedge of cold on the southern flank & also a wedge of deep polar cold sinking SE- these are rare rare ingredients over the UK - make the most of them ignore they all align!!!

[shaky]

Jma continues on its merry with the ukmo route at 84 hours!!band of precipitation coming into the uk saturday with cold air in front and behind the front!!

[feb1991blizzard]

11 minutes ago, Steve Murr said:

 

The GFS has been slowly backtracking over the last 36 hours - eradicating the impact of the PV run by run but for many that didn’t matter as the cold was a long way east-

Now the alignment has sharpened up so much the GFS is chasing down the UKMO ( but not quite yet )

 

The weekend I was thinking, if ever we needed a 'Murr Gfs westward correction' it was then, its just unfortunate that it went too far before it started, the problem is its going to take us from Atlantic into no mans land, why cant one of these take us from no mans land into stonking convective Easterly territory.

[carinthian]

20 minutes ago, Seasonality said:

Very nice looking chart, like two armies charging towards each other and the point where they clash and do battle is smack bang over the UK.

Game of Thrones !

C

[SMU]

7 minutes ago, shaky said:

Jma continues on its merry with the ukmo route at 84 hours!!band of precipitation coming into the uk saturday with cold air in front and behind the front!!

Yep well spotted

JMA is sharper than the UKMO @84 @ gives snow risk in the UK-

low looks to close off Northern France which is a long way better than the GFS

Edited January 30, 2018 by Steve Murr

[SMU]

6 minutes ago, feb1991blizzard said:

The weekend I was thinking, if ever we needed a 'Murr Gfs westward correction' it was then, its just unfortunate that it went too far before it started, the problem is its going to take us from Atlantic into no mans land, why cant one of these take us from no mans land into stonking convective Easterly territory.

We may not be to far from the second favoured choice...

[inghams85]

6 minutes ago, feb1991blizzard said:

The weekend I was thinking, if ever we needed a 'Murr Gfs westward correction' it was then, its just unfortunate that it went too far before it started, the problem is its going to take us from Atlantic into no mans land, why cant one of these take us from no mans land into stonking convective Easterly territory.

Energy could well disrupt South East from that UKMO 144 chart with small further corrections mate it's 192-216 that holds possibilities from there mate

[feb1991blizzard]

Cant be sure from temp plots alone but I would imagine a lot of GEFS members would put us a few days away from SSW territory - and in a favourable position.