Model output discussion - here comes the beast!

[carinthian]

2 hours ago, carinthian said:

Hi Singularity, booked a chat with the team in an hour. Will get back with an up date with their thoughts and latest model predictions. Should be interesting from what I have seen of this mornings bigger model outputs to say the least ! C

Morning all, here is a up date from a foreign field as so to speak. Current picture below on our mountain, temp -8c. We have been given an upgrade in the cold for Tuesday with a forecast temp MAX of -20c on the top runs of the mountain, that's about at 850mb level, so shows how cold the air mass will be at that time. Forecast regarding UK , they put a lot of faith in the 300mb NH wind flow pattern from what I gather and its current orientation is ripe for a severe protracted cold block over much of Northern Europe including all of the British Isles. Regarding their own model its more inclined to ECM current output, maybe a bit more severe. They still expect snow is more likely from the east affecting the British Isles next week, especially mid week as their own chart still shows a significant disruption in the flow or possible low formation coming out from Poland direction. They appear less keen on the attack from the SW/S to make much head way into Blighty, maybe making limited progress at best and more likely to be repelled back to the other side of the channel ( but that is still a long way off ) so for the time being look EAST is their advice for snow . In the longer term they still expect the deep core of cold  to be over Scandinavia/ Arctic Russia with pulses of cold air continuing to advect towards the British Isles , especially another cold pool showing at  around10 days time again. OK , hope that helps a bit. This will be my last post for a week as I am off to Rauris for a ski-ing holiday and meeting up with a few old cricketing rascals out from Blighty.. Best of luck with the snow and will be looking forward to pictures on this site next week of ice flows down the Thames and deep snow drifts on the Berkshire Downs!

C

[Weathizard]

With regards to systems approaching us from the south, am I correct in saying as long as the flow is continental then snow is still possible even with -5 uppers or even a little higher in march? I've heard stories about snow falling with 0 850's due to dew points off the continent.

 

[Mr Frost]

I am near speechless - these three charts from the GFS 06z low res are just mind blowing. 

Honestly what else can we all say!? This is the pinnacle of Winter weather watching. All those years people have spent on here logging on everyday to check the latest charts at all hours of the day, refreshing the Metoffice APP to see if our location has updated to show a single snowflake every Winters day and just hoping/willing that charts at 384 hours away make it down to the reliable. It has all been leading to this! 

When it does arrive get out and enjoy every second of it - if you can. You just never know how long it could be before it happens again! This is what being a lover of snow/extreme weather is all about! 

Cheers everyone! 

 

 

Edited February 23, 2018 by Mr Frost

[JamesL]

1 minute ago, Weathizard said:

With regards to systems approaching us from the south, am I correct in saying as long as the flow is continental then snow is still possible even with -5 uppers or even a little higher in march? I've heard stories about snow falling with 0 850's due to dew points off the continent.

 

Correct ?

[Man With Beard]

ECM clusters. We're pretty well set to T144, so beyond that

T156:

Bit of a split between runs getting a weak trough to move down from the north. All runs bitterly cold except I imagine cluster 4 (7 out of 51 runs) which I imagine may inject quite a bit of PM rather than PC air into the pattern by T168 (but still supportive of snow I'd guess)

T192 and T240:

  

So now it's getting messy. Cluster 1 keeps the UK on the colder side. Cluster 2 possibly does too (like on the op run) but gets close to allowing slightly less cold air in from the south. I still don't see how we can avoid a decent snow event for many between D7-D10, despite the current snow charts.

Just too messy to make a call further out than that, but cold rather mild favoured I think especially further north.

 

 

 

[East_England_Stormchaser91]

38 minutes ago, frosty ground said:

Please note this is not a guarantee 

 

By Thursday expected snowfall totals..... (look away greater Manchester) 

 

Is that a 40 I see there right on top of Newcastle :O! 

[shuggee]

A sledge load of off topic posts moved here:

https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

[Banbury]

Have to say I’d rather the LP be further North

[DOdo]

Sorry Posted into wrong forum

Edited February 23, 2018 by DOdo
Posted into wrong Forum

[bluearmy]

21 minutes ago, Man With Beard said:

ECM clusters. We're pretty well set to T144, so beyond that

T156:

Bit of a split between runs getting a weak trough to move down from the north. All runs bitterly cold except I imagine cluster 4 (7 out of 51 runs) which I imagine may inject quite a bit of PM rather than PC air into the pattern by T168 (but still supportive of snow I'd guess)

T192 and T240:

  

So now it's getting messy. Cluster 1 keeps the UK on the colder side. Cluster 2 possibly does too (like on the op run) but gets close to allowing slightly less cold air in from the south. I still don't see how we can avoid a decent snow event for many between D7-D10, despite the current snow charts.

Just too messy to make a call further out than that, but cold rather mild favoured I think especially further north.

I think the eps clusters show that any prediction on how this will play out beyond day 4 is basically a punt ! Too many variables in the mix with the downwelling wave subsiding together with the reverse zonality easing off bit by bit and the jet trying to get back north. The push from the north/northeast should be the stronger force here but how it all interacts is going to prove a problem for the models and more importantly us, especially when small differences in system placements and tracks will make massive differences in surface conditions.

i guess we will be paying more attention to the short range models now so perhaps won’t be so exercised by the mid term continuity !

Edited February 23, 2018 by bluearmy

[Bobby93]

2 minutes ago, Banbury said:

Have to say I’d rather the LP be further North

Further south the better imo, keeps us all in the colder air for longer with no chance of mild muck sneaking in.

[dixonoid]

That awkward moment you accidently read the model discussion archive, with massive down grades :-@ Back to the present, lol , looking cold for the foreseeable and with the extra stratosphere warning, maybe with us for a while :-)

[Norrance]

46 minutes ago, Interitus said:

This article from the Meteorological Society Weather journal is worth reading at this point - An historical and climatological note on snowfalls associated with cold pools in southern Britain - http://onlinelibrary.wiley.com/doi/10.1002/wea.666/pdf

Jan 1987 rates as the record deep cold pool at around 495/496 dam 1000-500mb thickness.

The authors say -

In fact that whole edition of the journal from Jan 2011 is freely available and is a special issue focused on severe winter weather and worth a look for those inclined -

http://onlinelibrary.wiley.com/doi/10.1002/wea.v66.1/issuetoc

That second link is in my favourites and makes for very interesting reading. If the models are correct as now looks likely late Winter 2018 may soon get a mention?

[ukpaul]

16 minutes ago, Banbury said:

Have to say I’d rather the LP be further North

It wouldn’t stay north anyway. The likelihood, with it so far south, is that it will miss the UK completely (maybe not the Channel Islands) given the usual direction of travel as we count down to zero hour. The battle at this stage is over whether a northerly incursion gets there first and you can see suggestions in this morning’s output that it will. This might suppress anything next weekend but it gets rid of any potential days with milder uppers and brings new opportunities of fronts working their way down the country.

EDIT: Going through GEFS members, everything is on the table equally: missing completely to the south, clipping the south, moving up through the country or so far north it brings a warm sector to southern counties. 

Edited February 23, 2018 by ukpaul

[Banbury]

2 minutes ago, Bobby93 said:

Further south the better imo, keeps us all in the colder air for longer with no chance of mild muck sneaking in.

Sorry , I should have been clearer , further North...stalling before moving off

[Chris.R]

GFS 06Z deserves an OMFG again this morning. We saw these ridiculously low thicknesses and 850s when they were in FI but never thought they would still be here now; then they got watered down a bit; now they’re back. Amazing. 

[joggs]

Just want to thank the mods for been a touch lenient through this crazy period.

Please don't delete this?

[A.J]

47 minutes ago, Nick F said:

Thanks for the links, will thoroughly enjoy reading those articles.

06z GFS goes for another attempt from the Atlantic to introduce milder air from the SW on Sunday 4th March, but wouldn't be surprised if this fails too like the Friday low coming into France and probably staying south of the UK. Have to pinch myself that these unusual synoptics showing are actually likely 

a bit of an IMBYism, but there are many of us in the West Country who would prefer the modelled low for next friday track further north as well as the projected sunday week low....Whilst it will be bitterly cold for our part of the UK, our best chance down here for meaningful snow is a battleground/channel low scenario  (that's not to say some of us won't see snow showers from time to time)

[ItIsGee]

looks like the channel low will be too far south for snowmaggedon? 

 

[sparky1972]

morning all, hopefully another day of fab output to come, just 1 quick question, if there was to be a turn around in the depth of cold/snow etc to something alot less cold and less servere, what could the models of over/under estimated?

[philglossop]

1 minute ago, Crashlanding said:

looks like the channel low will be too far south for snowmaggedon? 

 

Depends on the location of the fronts I guess. The warm sector is certainly in France but it’s the location of the occlusion I’d be interested in

[FetchCB]

2 minutes ago, Crashlanding said:

looks like the channel low will be too far south for snowmaggedon? 

 

But would  spark heavy snow showers with such cold uppers?

[smhouston]

I'm not one to usually post on here and I'm definitely one not to ramp. Even the last failed cold spell I warned people not to dismiss the GFS, so I'd like to consider myself pretty grounded when it comes to these situations!

However, wow. I've been a member for a while on here and watch every winter for a special events to be modeled and then disappear eventually, but this one is something else. An absolutely classic winter spell is on the cards as much as I personally don't want it to be atm. How deep the cold gets, and the amount of shower activity to be generated off the North Sea, is something else.

The models will be right this time, except for that low to the south I reckon. All down the east side of the country is 100% going to get an absolute pasting, and no doubt other areas will too. Do not underestimate how heavy and consistent the showers can be generated off the North Sea, and that will not be known until T0.

Literally the best charts I've seen so close to the time from all my years on here, which is quite a long time now (14 years).

For a different thread, but extremely surprised how this has not been publically escalated by the METO. Absolutely dangerous conditions coming up...it's not the snow that kills. Extremely worrying just how cold it'll get and there are a lot of vulnerable people out there.

[Frosty.]

Good news is most of the GEFS 6z keep the cold and indeed reinforce it from the North at the time the 6z op became milder..so a prolonged very cold spell is more likely than not! ..and what a week we have in store

[Banbury]

Control has it right for me