Model output discussion - the beast arrives

[Weathizard]

Bit of an odd 120 UKM chart after the day 4 chart, we have some disruption eastwards though.

[Mark Neal.]

2 minutes ago, Singularity said:

GFS still took the deep low further N and then had it move W toward the Azores low despite that one being further W... so pretty unconvincing there, but look how it has the disruption sending a shallow low east to pass S of the UK.

This brings the cold back down into the frontal system just as it moves NE - resulting in what at first glance appears to be an all-snow event even in the far S. Need to see higher-res to confirm though.

There you go Singularity. 

[CK1981]

8 minutes ago, Steve Murr said:

UKMO 96-

It looks like a total turn around back to cold as most expected

Looking for snow moving west out of low countries 96>120

@CK1981

 

Great to see ?

[bradymk]

Well the GEM would be one big event thurs/Friday.

look how tight isobars are in southern UK at +72/78

blizzards. 

Good trend so far this afternoon.

[Mark Neal.]

System from SW does move NE on Friday afternoon/evening. Snow totals go up quite quickly especially into Midlands/Central Southern England and parts of SW.  Freezing rain potential showing in M4 southwards though again. GFS 12Z. 

  

Edited February 26, 2018 by Mark N

[Summer Sun]

t120 shows the differences between ICON 12z and GFS 12z

[Derecho]

GFS looking like the odd one out so far but its over changes of the tiniest margins. The GFS has the low slightly further west then the others when approaching Spain/Portugal. When the low starts turning to the north, placement further east allows the low to disrupt. ICON and GFS show this well. Meanwhile on the GFS it is pulled westwards and interacts with another low to the SW of it.

This one won't be resolved till T48 I think

[Mike Poole]

GFS not quite with the new trend, here still showing the freezing rain risk for the south at T102

Further west than other 12s so far at T114

Edited February 26, 2018 by Mike Poole

[AWD]

Was hoping for a slightly better upper air profile when viewing the pressure chart at T96 on the UKMO;

Although, for balance, it is a very brief visit of the 0c Isotherm into England admittedly.

[Summer Sun]

UKMO t120 looks to be around halfway between GFS and ICON with the colder air

 

 

 

[claret047]

2 minutes ago, pages said:

yep still not convinced  frontal snow will actually reach UK.

Hello Pages,

If the frontal snow does not actually reach the mainland, will the attendant lowering of pressure and increased wind speed result in more shower activity from the east?

2 minutes ago, Mark N said:

There you go Singularity. 

Hello Mark,

Well done on Saturday's win. We were shockingly bad according to our messageboard and our manager was certainly not best pleased! 

Back on topic does the chart you displayed show the furthest extent the precipitation will travel?

Kind Regards

Dave

[Singularity]

2 minutes ago, Mark N said:

System from SW does move NE on Friday afternoon/evening. Snow totals go up quite quickly especially into Midlands/Central Southern England and parts of SW.  Freezing rain potential showing in M4 southwards though again. GFS 12Z. 

  

Yeah... it actually kind of 'undoes' the trough disruption. Seems legit .

Also seeing some hints from the 12z runs so far that the Azores low may not merge with the one by the UK. UKMO a notable exception though, while by contrast, ICON really goes for it.

 

 

Still a lot to be resolved. 

If trends were to continue, the weekend would actually end up being the focus for snow events in most areas. That'd be a turnout for the books!

[Youcan'tbecirrus]

19 minutes ago, warrenb said:

The shift ties in quite nicely with the new weather warning for the SE for Friday of possible deep snow

But at odds with the Met Office forecast I just watched which seemed to be indicate milder air pushing in. Have to admit to being confused at the moment.   

[pages]

2 minutes ago, claret047 said:

Hello Pages,

If the frontal snow does not actually reach the mainland, will the attendant lowering of pressure and increased wind speed result in more shower activity from the east?

Hello Mark,

Well done on Saturday's win. We were shockingly bad according to our messageboard and our manager was certainly not best pleased! 

Back on topic does the chart you displayed show the furthest extent the precipitation will travel?

Kind Regards

Dave

hi Claret easy way to think of it is move everything on that chart further south obviously bit more complex but will give general idea.

[Chortle2001]

5 minutes ago, Youcan'tbecirrus said:

But at odds with the Met Office forecast I just watched which seemed to be indicate milder air pushing in. Have to admit to being confused at the moment.   

Forecast is always lagged to previous models which were showing milder air. 

[Catacol]

Ooohhh - I'm really liking ICON this afternoon. The perfect end scenario after wobbles of the last few days. Disrupt, pivot and slide....

[pages]

2 minutes ago, Chortle2001 said:

https://www.metoffice.gov.uk/public/weather/warnings#?date=2018-03-02

 

Warnings shifted to include much more of south and east. This was only updated short time ago, maybe Met see same trend as this afternoons runs?

I imagine  MOGREPS is run at 12z aswell and with their computing power probably completes output earlier. they would of analysed and discussed that and used for warning.  personally I think its going to end up much further south and it will be next low behind that will give somewhere a blizzard. 

Also what people may of been missing  focusing on low at end of week is now the high is retrogressing slower the pressure gradient is being increased between t42-t54 and we are pulling in the minus 16 uppers which weren't showing yesterday. upgrades in short term in terms of snow totals for East coast.

[Sawel]

2 minutes ago, Catacol said:

Ooohhh - I'm really liking ICON this afternoon. The perfect end scenario after wobbles of the last few days. Disrupt, pivot and slide....

The UKMO, GEM and ICON all keen to keep much of the country cold into next week. I wonder if the ECM will joint the party later. 

[Fiona Robertson]

11 minutes ago, Chortle2001 said:

https://www.metoffice.gov.uk/public/weather/warnings#?date=2018-03-02

 

Warnings shifted to include much more of south and east. This was only updated short time ago, maybe Met see same trend as this afternoons runs?

Also amber warning of disruptive snow now extended further west through the central belt of Scotland to include Glasgow. Previously Livingston was just inside the amber warning area. Looks like Tues/Wed will be nasty through the M8 corridor.

[Frosty.]

The Gfs 12z looks quite springlike in the south on sunday

[johnwirral]

12 minutes ago, Chortle2001 said:

https://www.metoffice.gov.uk/public/weather/warnings#?date=2018-03-02

 

Warnings shifted to include much more of south and east. This was only updated short time ago, maybe Met see same trend as this afternoons runs?

Looks similar to the GFS, rather than the ICON, snow on Thursday for SW heading north and east for Friday

[Trom]

2 minutes ago, pages said:

I imagine  MOGREPS is run at 12z aswell and with their computing power probably completes output earlier. they would of analysed and discussed that and used for warning.  personally I think its going to end up much further south and it will be next low behind that will give somewhere a blizzard. 

Also what people may of been missing  focusing on low at end of week is now the high is retrogressing slower the pressure gradient is being increased between t42-t54 and we are pulling in the minus 16 uppers which weren't showing yesterday. upgrades in short term in terms of snow totals for East coast.

The slower retrogression of the high pressure is having the impact of keeping that low further South.  

[Snowmaggedon]

2 minutes ago, johnwirral said:

Looks similar to the GFS, rather than the ICON, snow on Thursday for SW heading north and east for Friday

How far north and east does it get?

[Derecho]

For what its worth the GEM still phases Friday's low with the second Azores low to the SW, I can imagine the UKMO does the same looking at the T120h chart with less cold uppers, everything is just shunted further east compared to the GFS. ICON however just weakens the low and milder air makes no inroads on Friday. Would be perfect for us snow starved southerners.

 

I thought the UKMO at T96 would have colder uppers for the south however.

I think the further east the incoming low is on Friday the more likely it is to disrupt with the UKMO and GEM getting close to the ideal scenario. Someone just needs to tell the GFS...

Edited February 26, 2018 by Quicksilver1989

[Mike Poole]

4 minutes ago, Frosty. said:

The Gfs 12z looks quite springlike in the south on sunday

It does, but I think it lost the plot some time before these charts!