Model output discussion 24/01/21

[Mike Poole]

ICON T120 v 0z T132

A rare post in here. A big downgrade!  

But still it is only the ICON!

[Tim Bland]

Icon looks similar to the ECM with a chance of snow in the south on Sat...

[nick sussex]

6 minutes ago, Mike Poole said:

ICON T120 v 0z T132

A rare post in here. A big downgrade!  

But still it is only the ICON!

Ironically that nearly cuts off the mini wedge , it’s a shame it stops at day 5 . Would have been interested to see how it would have resolved any trough disruption given the energy should move se towards the low over France .

[bluearmy]

5 minutes ago, Mike Poole said:

ICON T120 v 0z T132

A rare post in here. A big downgrade!  

But still it is only the ICON!

I could make the argument that the new day 5 icon has much shallower lows to our west which are more likely to trundle south east than head northeast like the deeper 12z feature 

[Mike Poole]

1 minute ago, bluearmy said:

I could make the argument that the new day 5 icon has much shallower lows to our west which are more likely to trundle south east than head northeast like the deeper 12z feature 

You could.  In fact that is one of the interesting features of model watching this year, isn’t it, without a Greenland centered vortex powering things, what is coming off the Atlantic is, it seems to me, a bit more like summer, a bit random.  If that makes sense.  We won’t know re the ICON, but eyes down for the pub run...

[Eskimo]

Fronts struggling against the colder air - being pushed south west on each run. 


 

[Griff]

Any point looking further ahead when gfs vs parallel look so different? 84 hours 

(obviously yes ) 

[Mike Poole]

Just now, Griff said:

Any point looking further ahead when gfs vs parallel look so different? 84 hours 

(obviously yes ) 

Well, yes for fun @Griff but probably not for meaningful analysis!  Won’t stop us I’m sure.....

[nick sussex]

After going on a mystery tour for the first part of its GFS 18 hrs run with a series of shortwave dramas it somehow finds its way back to the similar path of the earlier 12hrs run. 

[feb1991blizzard]

4 minutes ago, nick sussex said:

After going on a mystery tour for the first part of its GFS 18 hrs run with a series of shortwave dramas it somehow finds its way back to the similar path of the earlier 12hrs run. 

It was some ending to that run for SE England in terms of longjevity of severe -ve daytime max temps and a penetrating wind chill factor.

[Snowman.]

Para vs GFS T102

 

 vs 

[Allseasons-Si]

Clearly fl is as early as 78 hours

the difference from there escalates until we know how far this trough pushes NE from the SW on Thursday.

[Mike Poole]

GFS 18z // T120 -will it or won’t it go under?

[Day 10]

1 minute ago, Allseasons-si said:

Clearly fl is as early as 78 hours

the difference from there escalates until we know how far this trough pushes NE from the SW on Thursday.

Even the progressive GFS is starting to slow it down.

[Snowman.]

  

Well

[Griff]

GFS might be attempting a repeat 

[weirpig]

Arperge 18z   shows quite a bit of snow for the peaks  north on Wednesday  Thursday  

Downside is the  front really struggles  and brings  copious amounts of rain elsewhere  particularly   down the spine of the country  

 

[Mike Poole]

GFS // 18z at T144, is this really going to go under such a small wedge of heights:

If it is, it kind of sets the benchmark for what systems might get deflected SE on the jet...no matter the rest of the run, I think it shows we are very much in the game re sliders until something more meaty comes along, which it well might.

[Griff]

Different day 10 but still worth a watch... 

[chris55]

1 hour ago, Mike Poole said:

ICON T120 v 0z T132

A rare post in here. A big downgrade!  

But still it is only the ICON!

Upgrades/downgrades its all relative.

I actually prefer the 18z ICON to the 12z. Getting that low further north into the southern half of the UK gives a better chance of northern edge snowfall as the colder air digs in from the east.

 

GFS can't even be arsed with it lol...

 

Another period with inter-run inter-model discrepancy regarding the modelling of these Atlantic lows and how they interact with the colder air to the north/north east.

 

Edited January 25, 2021 by chris55

[nick sussex]

1 minute ago, Mike Poole said:

GFS // 18z at T144, is this really going to go under such a small wedge of heights:

If it is, it kind of sets the benchmark for what systems might get deflected SE on the jet...no matter the rest of the run, I think it shows we are very much in the game re sliders until something more meaty comes along, which it well might.

Shows the importance of that spoiler shortwave west of Norway in some of the other outputs . That stops a wedge there which the para has. 

 

 

[Allseasons-Si]

This is a marked difference in the gfs/p at 144 hrs as the 12z had a shortwave in the Norwegian sea where as the 18z doesn't hve it and had a cleaner flow from the NE.

18z 138 v's 12z 144

these small differences make a huge difference as to get colder air to the UK,one to watch in future runs.

[Snowman.]

We do have the wedge. Not enough for southern UK but cold north of it. Can easily see a route to better cold there.

[nick sussex]

2 minutes ago, Allseasons-si said:

This is a marked difference in the gfs/p at 144 hrs as the 12z had a shortwave in the Norwegian sea where as the 18z doesn't hve it and had a cleaner flow from the NE.

18z 138 v's 12z 144

these small differences make a huge difference as to get colder air to the UK,one to watch in future runs.

Someone needs to nuke that shortwave !  If only so the thread doesn’t have to put up with my obsession over it . I’ve been droning on about it all evening!  

[Griff]

Just for fun para will no doubt amplify but look at cold nearby... And heights jammed in to the north.