Model output discussion - The run up to Christmas

[Stu_London]

compared to recent output - the long term prospects for cold on the 06z is pants.

luckily only one run and in FI - hopefully not the start of a trend. 

My concern with these forecasting models is whilst they often overstate the cold, when it comes to the mild, they are usually eerily accurate.

[I remember Atlantic 252]

FI around 3-4 Jan, 00Z and 06Z, flirting with battleground snaw? 00Z was good, 06Z less so, may end up with similar to this? snowy Saturday, I remember it

[kold weather]

1 minute ago, sheikhy said:

Doesnt matter which way you look at it!!west based east based north based its cold regardless!!!!looks whats coming in from the north east!!06z threatened a west based nao but never went full whack so now the low is disrupting!

Yes the upper high though weakening does actually drift back SE towards a more favourable position by 324hrs which does leave the doors open again.

However the west based -ve NAO is a real risk, looking through the archive charts from the past I've seen some utterly stunning upper blocking and strong southerly jet get ruined because the upper high set-up too far NW and we end up with a very wet LP train with SW airflow.

[offerman]

1 minute ago, Stu_London said:

compared to recent output - the long term prospects for cold on the 06z is pants.

luckily only one run and in FI - hopefully not the start of a trend. 

My concern with these forecasting models is whilst they often overstate the cold, when it comes to the mild, they are usually eerily accurate.

 Completely agree with you there Stu, I noticed this over the years too. I wonder why it often overstates the cold? 

[sheikhy]

1 minute ago, kold weather said:

Yes the upper high though weakening does actually drift back SE towards a more favourable position by 324hrs which does leave the doors open again.

However the west based -ve NAO is a real risk, looking through the archive charts from the past I've seen some utterly stunning upper blocking and strong southerly jet get ruined because the upper high set-up too far NW and we end up with a very wet LP train with SW airflow.

The control run at 180 hours❄

[bluearmy]

This run is a great illustration of the high risk/high reward that a slight west based NAO can also deliver ....adjust everything a few hundred miles and you have winter nirvana ..... the cold fights back aswell on this run which is even better for the worries ...

[mountain shadow]

8 minutes ago, Sceptical said:

Theres yellow warnings, for snow and ice, that cover the northern half of Scotland today and tomorrow.

So, the Met Office back me up then?

I think we have to be realistic here.

Yes, some will get lucky with snow in the next ten days, but it's VERY hit and miss and it goes without saying that the further North with altitude you are, the better.

[North East Blizzard]

 

Control looks better to my untrained eye

[offerman]

21 minutes ago, Djdazzle said:

Can someone please explain what is meant by a west based nao?

My understanding is that means north Atlantic oscillation.

normally things move west to east from the Atlantic but this could be reversed into a west based meaning moving east to west so a neg Atlantic isolation . 
 

i'm no expert and will probably be corrected.

 

[Allseasons-Si]

The gfs get's it's easterly wheels back on but too far out to be concerned about 300+charts

[TSNWK]

What time and where can I view the spaghetti plots please.. be good to see where this run sits against the pack from around 250.. I’m hoping for a green line bump...around 300

taken this 06z operational at face value we all go cold from Monday snow chances for all. This lasts until the weekend whereby the southern half of uk is affected by milder air as a consequence of the west based nao.. northern half of uk stays cold.

After a couple of days crac in south it looks like we look north east for the next slice of cold..which would be harsher I suggest

not bad

[Drifter]

12 minutes ago, Stu_London said:

compared to recent output - the long term prospects for cold on the 06z is pants.

luckily only one run and in FI - hopefully not the start of a trend. 

My concern with these forecasting models is whilst they often overstate the cold, when it comes to the mild, they are usually eerily accurate.

Yep, frozen pants. 

[Stu_London]

1 minute ago, Drifter said:

Yep, frozen pants. 

Rain for me, down here in Royal Tunbridge Wells

[LRD]

FI on the 6z GFS makes me all nostalgic for some of those 80s winters where we'd get cold rain, turning to snow, turning back to rain before, finally, turning to snow. 

High risk/high reward as bluearmy stated earlier

Next week - some places will get snow. Still to be revealed exactly how many places and exactly where of course. But the chances are there. Around New Year we could see a battle of cold vs mild over the UK before, maybe just maybe, deeper cold eventually wins by early/mid-January. SSW will likely play a hand too (not necessarily for the good of course but we'll see). All speculation of course but, even if this amounts to very little, this is by far the best model watching we've had for almost 8 years. EIGHT years. And still some are trying to pick various holes in it. I'm really not sure what people are hoping for (I suspect it's something completely unrealistic for our part of the world). What we are seeing is a throwback to some of those late 70's/early-mid 80's winters. With a bit of 1990-91 and 1995-96 thrown in. Just hope they verify

[kold weather]

15 minutes ago, mountain shadow said:

So, the Met Office back me up then?

I think we have to be realistic here.

Yes, some will get lucky with snow in the next ten days, but it's VERY hit and miss and it goes without saying that the further North with altitude you are, the better.

I think I'm being very realistic personally, and I see nothing yet to swing me from my position that there will be a fairly decent area of snow between the 28-29th. It may well be marignal in some places and by more wintry in nature and obviously how well it sticks might well be a different question, but snow itself, I'm fairly confident it will be around. Especially on the cold flank of any secondary low.

I think your being pessimistic and simply looking at 850hpa to heavily. As I said before a similar but milder set-up gave Kent and EA snow a few weeks back.

also, far too early for any met office warnings, alot is going to depend on exactly where any secondary depressions set-up, which probably won't be known with any real confidence till the 26th I'd guess.

Edited December 23, 2020 by kold weather

[Methuselah]

Back in the days of yore (when sea-ice was way more extensive and SE Europe was nowhere near as warm as it is today) I'd have taken one look at a chart like these and thought a reload from the north almost certain. These day's however, it's anyone's guess?

    

[johnholmes]

3 minutes ago, General Cluster said:

Back in the days of yore (when sea-ice was way more extensive and SE Europe was nowhere near as warm as it is today) I'd have taken one look at a chart like these and thought a reload from the north almost certain. These day's however, it's anyone's guess?

    

What on earth is the point being concerned about a chart SIXTEEN days ahead?(no apology about the capitals)

Get real

when I get time I will post a set of my usual charts with comments

Edited December 23, 2020 by johnholmes

[LRD]

I mean look at this and remember where we were this time last year

It's one frame from FI and not worth over-analysing but if that trough to our SW titls a little more neagtively and elongates and heads to nothern Italy, cold would probably lock in for a fortnight

And compare to early Jan 2020

...and think how much better it looks (at this stage) for Jan 2021

In troubled times this is a welcome distraction

[phil nw.]

Yes later 06z gfs would make for some interesting battleground weather.Snow/rain/snow as mild and cold fight it out before cold wins from the north east in this case.

We really have got a different pattern setting up in the next few weeks it seems.Zonal winds trending down so a continued weakened vortex with wedges of heights pushing into the Greenland area and forcing lows se this way with low thicknesses.

A bit of a throwback to Winters past.

[Day 10]

Couple of little features Christmas Eve clipping the east coast, maybe a few wintry showers giving a festive feel to some?

[MR EXTREMES]

1970mb greenland heights surely thats record breaking?

2010 neg nao and central pressure was around 1050-1060mb......

[Battleground Snow]

Don't respond to the obvious   post guys

What a mean for 240!

 

Edited December 23, 2020 by Battleground Snow

[Methuselah]

17 minutes ago, johnholmes said:

What on earth is the point being concerned about a chart SIXTEEN days ahead?(no apology about the capitals)

Get real

I'm not being 'concerned' at all, John (merely mentioning two things that are factual -- unless you know otherwise?)... So 'getting real' has nowt to do with it!

At the end of the day, I couldn't give stuff as to what computer models show at Day SIXTEEN!

Edit: Or, to put it another way: were it a Day 6 chart, I'll still be thinking along the same lines...

Edited December 23, 2020 by General Cluster

[Allseasons-Si]

There is always one...

anyway,the gefs mean out to day ten is still rock solid,infact,it's even better than the 00z

check this out...

 

[Matt H]

06z ensembles looking cold into the first week of January, certainly nothing notably milder is looking likely anytime soon. Averaging well below average from the 28th onwards with a few members turning very cold in the new year.

Day 10 mean is also fantastic!