Model output discussion - proper cold spell inbound?

[karlos1983]

You look at the precipitation chart on the ICON and the difference is big, look at the angle of the front from the 12z to the 18z

very typical of systems struggling against a block(use the term loosely for now)

 

[SMU]

Nice they have also labelled the probability out of 100 as well

[shaky]

1 minute ago, karlos1983 said:

You look at the precipitation chart on the ICON and the difference is big, look at the angle of the front from the 12z to the 18z

very typical of systems struggling against a block(use the term loosely for now)

 

What an upgrade!!didnt expect it to be this obvious!

[BlakeyWeather]

A wild Saturday night in watching the GFS 18z roll out. Good luck gang

[MattStoke]

Tuesday's front dies completely across Wales and Northern England on the ICON. It's previous run had it pushing all the way across England.

[Met4Cast]

Just now, MattStoke said:

Tuesday's front dies completely across Wales and Northern England on the ICON. It's previous run had it pushing all the way across England.

Pretty much in line with what the APERGE has been showing for a good few runs now

[sausage]

1 minute ago, MattStoke said:

Tuesday's front dies completely across Wales and Northern England on the ICON. It's previous run had it pushing all the way across England.

gfs thinks different!

[snowice]

7 minutes ago, BlakeyWeather said:

A wild Saturday night in watching the GFS 18z roll out. Good luck gang

Looks like a stella run

[Met4Cast]

1 minute ago, sausage said:

gfs thinks different!

GFS will be wrong. The ICON is the first model to correct back from it's over-progressive pushing the front across the entire country, GFS will probably be next. Historically in these setups fronts just don't survive long coming in against a cold block. 

I think the APERGE is along the right lines, Scotland, Northern Ireland, Northern England then it dies fast

[sausage]

3 minutes ago, KentishDan said:

GFS will be wrong. The ICON is the first model to correct back from it's over-progressive pushing the front across the entire country, GFS will probably be next. Historically in these setups fronts just don't survive long coming in against a cold block. 

I think the APERGE is along the right lines, Scotland, Northern Ireland, Northern England then it dies fast

it normally gets to about north wales yorkshire thoigh as the pennines dry it out before fading right?!

[Met4Cast]

Yup. 18z GFS less progressive on Tuesdays front too, killing it off faster than previous runs

[JBMWeatherForever]

The models seem to by backtracking again as I thought they would. I just didn't think it would start quite so soon!  This has to mean that the end result will be much better for those who like the cold ! What a great weeks weather we have to look forward too !! 

[cheese]

9 minutes ago, KentishDan said:

GFS will be wrong. The ICON is the first model to correct back from it's over-progressive pushing the front across the entire country, GFS will probably be next. Historically in these setups fronts just don't survive long coming in against a cold block. 

I think the APERGE is along the right lines, Scotland, Northern Ireland, Northern England then it dies fast

I can't be the only one who thinks the accuracy and reliability of the high-res models leaves a lot to be desired. 

[ukpaul]

GFS pretty good so far, some form of snow for nearly all areas as the front pushes through before dying off. No sign of any warm sector but it may be too late to rescue Thursday into Friday, that warm sector looks just too big at the moment and the block too weak.

[SMU]

GFS 18z 120

struggling to get the Atlantic down south before being swerved away...

mild air squeezed out - Snow for midlands

Edited February 3, 2018 by Steve Murr

[andymusic]

1 minute ago, ukpaul said:

GFS pretty good so far, some form of snow for nearly all areas as the front pushes through before dying off. No sign of any warm sector but it may be too late to rescue Thursday into Friday, that warm sector looks just too big at the moment and the block too weak.

plenty of time for it to be SQUEEZED a bit tighter lol

Edited February 3, 2018 by andymusic

[Shunter]

The 30hpa zonal wind speed is currently increasing ( currently just below 40m/S   ) which may explain the earlier runs today showing a more progressive jet stream and associated eastward energy burst. However looking at the 12z GFS ensemble mean (below) this increase appears to peak Tomorrow / Monday and then falls away dramatically until the “potential” reversal ( SSW)  around mid month. 

It may be that the latest model runs are now factoring in the slowdown in zonal wind speeds as we move through the coming week. Is so then I would expect to see more of an Eastward correction with the Siberian HP nudging closer.

[andymusic]

looking like snow for Thursday/Friday on this run - north west - and east cold wedges meet again

Edited February 3, 2018 by andymusic

[karlos1983]

18z v 12z

18z less progressive with the front and uppers more favourable = more snow chances. That’s a good 100 miles further west.

Edited February 3, 2018 by karlos1983

[MattStoke]

ICON precipitation charts for Thursday.

  

That's as far as the model goes. Rain for Northern Ireland and Western Scotland. Snow elsewhere, turning to rain in western fringes.

Edited February 3, 2018 by MattStoke

[SMU]

Can we squeeze at Easterly at 168 ( reversal from Westerly idea )

[karlos1983]

1 minute ago, Steve Murr said:

Can we squeeze at Easterly at 168 ( reversal from Westerly idea )

ECM hinted at this earlier at 144-168 timeframe. 

Edited February 3, 2018 by karlos1983

[shaky]

1 minute ago, Steve Murr said:

Can we squeeze at Easterly at 168 ( reversal from Westerly idea )

All of a sudden the gfs is showing it all snow across england like it was a few days ago!brilliant upgrades this evening!!model watching at its best!!

[ukpaul]

Take it back, the slight delay and just enough of a squeeze allows the front to hit at more favourable times and without compromising dewpoints, although it's pretty knife edge for a while.

Edited February 3, 2018 by ukpaul

[Duane S.]

There has been a subtle but definite trend for the Azores High to link again with the ever increasing ridging SW of the NE block next weekend. Underplayed, just like before next weeks was. 18z continues the trend.

The 12z P7 shows it well wth the more pronounced trough disruption having occurred...

This is what we want to see. An Easterly will follow on.