Model output discussion - Jan 3rd onwards

[daz_4]

After December with the pattern too west we are on our way to have January with everything too east. Looks like 6z could deliver something by 384h though 

[Tim Bland]

A rare chart. Not sure what to make of it

[Griff]

1 hour ago, Griff said:

Out of character for me to look at model impact at short range but a quick rather confusing comparison of precipitation for tomorrow IMBY (because I know everyone loves that here).... 

GFS 2°c with snow

ICON 0°c with sleet 

Not sure that even a pinch of salt or grit will be required. Possibly a misinterpretation from my Windy android app (gives a side by side comparison of GFS, ECM, ICON, METEOBLUE and AROME - the others aren't particularly interested in anything falling from the sky). 

Regardless of lack of snow, the last couple of weeks since Christmas day have been cold, rather colder than average, but slightly frustrating with regards to lingering frost etc. 

Sums up my cold chasing this winter 

[Climate Man]

Just now, Tim Bland said:

A rare chart. Not sure what to make of it

Look like full reversal but we need it to extend further South.

[Griff]

2 minutes ago, Tim Bland said:

A rare chart. Not sure what to make of it

Might that bad the dreaded west based -nao? 

[chris55]

1 minute ago, daz_4 said:

After December with the pattern too west we are on our way to have January with everything too east. Looks like 6z could deliver something by 384h though 

That is a majorly negative AO!

Highlighting how even with such a flow where the cold spills out is not guaranteed to affect a specific location!  

 

[Kentspur]

28 minutes ago, chris55 said:

GFS 6z still going with some ppn/snow tomorrow... The North, Midlands and East Wales look prone. 

 

 

 

And yet more rain in the GFS forecast for Kent oh the joy

[Tim Bland]

4 minutes ago, Climate Man said:

Look like full reversal but we need it to extend further South.

Gets there a day later. Could do with a few hundred miles further south though...

[Griff]

GFSP at 240 just about doing enough to stop me from asking to borrow Mr Murr's towel (to 'throw in')  

[IDO]

10 minutes ago, Griff said:

I'm growing old waiting for gfs 'potential' 

Yes, it seems like an equilibrium stasis, a pseudo blocking pattern, so this may be the precursor initial coupling? How long this settles for, assuming it is the solution, is the question?

I am determined not to draw any strong conclusions for a few days but it does seem that the core cold will dive into Asia with the sister vortex in Canada and we are relying on streams of cold ejecting from either for scraps? I have seen no op runs to date that suggests (atm) the UK will be favoured by the initial coupling. Hopefully it will simply flip for us in later runs?

[Griff]

Just now, Tim Bland said:

Gets there a day later. Could do with a few hundred miles further south though...

Good news is there's plenty of time for evolution!  

[Tim Bland]

Just now, Griff said:

Good news is there's plenty of time for evolution!  

Haha yes. Perhaps the snow desert of the south can cash in at the end of the month with battle ground events? Fits with meto thinking ...

[Griff]

Just now, Tim Bland said:

Haha yes. Perhaps the snow desert of the south can cash in at the end of the month with battle ground events? Fits with meto thinking ...

Just waiting for someone to complain that it doesn't show snow for Cornwall

[SqueakheartLW]

Maybe not so good on the models now as it had been but this regime chart still shows promise

Even if -NAO isn't the dominant option except for just 1 day it is overall still a good signal for colder than average right until the end of January. If you add up the -NAO, Block and ATR options they form an overall majority of the percentage on each day for really most of the chart from start to finish. These 3 options are the most likely to produce colder than average anyway

-NAO is no doubt probably the best signal to get NW Europe cold as long as it isn't too west based

Atlantic Ridge can be good if it is in the right place and combines with a nice Scandi trough to deliver us cold NW or N winds

Block is a bit more mixed but as long as it isn't to our E, SE or S we should come out colder than average, Scandi block is best

No regime could end up anything but knowing UK probably milder than average

+NAO worst option of course

Even if the regime chart shows +NAO dominating during early to mid February not worth reading too much into that since it is such long range anyway and the shorter range is overall average at worst and colder than average likely

[bluearmy]

Gfs op around 19/21st shows the current ens trend for this timescale 

I wouldn’t get hung up on the detail at that timescale 

[sebastiaan1973]

18 minutes ago, SqueakheartLW said:

Maybe not so good on the models now as it had been but this regime chart still shows promise

Even if -NAO isn't the dominant option except for just 1 day it is overall still a good signal for colder than average right until the end of January. If you add up the -NAO, Block and ATR options they form an overall majority of the percentage on each day for really most of the chart from start to finish. These 3 options are the most likely to produce colder than average anyway

-NAO is no doubt probably the best signal to get NW Europe cold as long as it isn't too west based

Atlantic Ridge can be good if it is in the right place and combines with a nice Scandi trough to deliver us cold NW or N winds

Block is a bit more mixed but as long as it isn't to our E, SE or S we should come out colder than average, Scandi block is best

No regime could end up anything but knowing UK probably milder than average

+NAO worst option of course

Even if the regime chart shows +NAO dominating during early to mid February not worth reading too much into that since it is such long range anyway and the shorter range is overall average at worst and colder than average likely

Have you seen the temperatures?

Edited January 7, 2021 by sebastiaan1973

[DanDorsetUK]

3 minutes ago, Griff said:

Just waiting for someone to complain that it doesn't show snow for Cornwall

You know it will drop South Its an improving picture. Going to get very interesting after the 2nd and 3rd warming. I still think things will look much better come then. This weekend I think we will begin to see the bigger picture. 

[bluearmy]

2 minutes ago, sebastiaan1973 said:

Have you see the temperatures?

It’s from the 46 ...... beyond jan is outside it’s paygrade! (Especially on temps)

[Tim Bland]

2 minutes ago, Rapodo said:

You know it will drop South Its an improving picture. Going to get very interesting after the 2nd and 3rd warming. I still think things will look much better come then. This weekend I think we will begin to see the bigger picture. 

Yes but as Blue says no point in getting hung up on the detail. I expect most snow lovers would bank this scenario. The boundary between rain and snow will likely shift north and south over time but most areas would see some snowfall at some point, it’s far from boring and the next best thing to a BFTE if you ask me!

[mountain shadow]

The 6z GFS for the 21st January matches up very well with the Met Office forecast of significant snowfall where the the bitter cold from the SSW meets the moist Atlantic air..

[Cold Winter Night]

My take from the runs this morning:

Still a growing Arctic High.
Still multiple spv lobes.
Still a tendency to increasing heights in Atlantic and GIN area.
Still lowering heights to our East.

The exact placement and strength of these features can make up to a 15-20C difference in our surface temperatures in a fortnight, with similar large consequences for precipitation type and amount.

No reason for being downbeat, no reason for being overly excited.
A great opportunity for everyone to practice their fence-sitting skills!

[mb018538]

People still getting hung up on 850 temps? Well - they’ve been around -7c/-8c here for days one end and we’ve not seen one flake of snow. Clearly, it’s a whole multitude of factors that need to be considered with the UK and borderline situations. If you just go off 850s, you’ll likely be stung unless they are at -10 or below.

[I remember Atlantic 252]

3 minutes ago, mb018538 said:

People still getting hung up on 850 temps? Well - they’ve been around -7c/-8c here for days one end and we’ve not seen one flake of snow. Clearly, it’s a whole multitude of factors that need to be considered with the UK and borderline situations. If you just go off 850s, you’ll likely be stung unless they are at -10 or below.

needs to be -10 here for convective snow! always said it, maybe different though for other areas

[Snowman.]

West based -NAO creeping into the GEFS...

[Bristawl Si]

46 minutes ago, mountain shadow said:

The 6z GFS for the 21st January matches up very well with the Met Office forecast of significant snowfall where the the bitter cold from the SSW meets the moist Atlantic air..

Looks dreadful. Thankfully, that chart is 2 weeks away, so wont happen, as shown.