Model output discussion - deep cold inbound?

[JoeShmoe]

3 minutes ago, bluearmy said:

The 00z run pushes an occlusion ne at day 7/8 which weakens as it gets to Scotland but doesn’t turn to rain on its journey   .....not a huge dump but a snow front nevertheless 

Yes shows on ECM quite nicely and think UKMO would evolve to that as well, still -10 uppers over the NE of the U.K. at that point so frontal snowfall for north Wales , north west and northern England . Milder in the south by that time as the low pulls up warmer air from the south 

[Griff]

A very quick scan through the models (before reading back from here) this morning, gfs op not as convincing as the others up until Thursday (regarding the south at least), all others as they were and potentially extending through Thursday? 

Fair assessment or did I miss something? 

Ta

[sheikhy]

Wow what a poor gfs ensembles from friday!!actually quite shocking big downgrade from the 18z!!you would think there is no attempt to repel the atlantic at all from all the other models as well when looking at that set!!

[bluearmy]

2 minutes ago, JoeShmoe said:

Yes shows on ECM quite nicely and think UKMO would evolve to that as well, still -10 uppers over the NE of the U.K. at that point so frontal snowfall for north Wales , north west and northern England . Milder in the south by that time as the low pulls up warmer air from the south 

That run doesn’t get the pos Dp’s in until around day 8/9 and even then ‘north of the M4’ stays sub zero until after day 9

have to give the modelling of the Atlantic a wide berth at that timescale anyway and take note of the surface scandi high 

[Guest]

4 minutes ago, sheikhy said:

Wow what a poor gfs ensembles from friday!!actually quite shocking big downgrade from the 18z!!you would think there is no attempt to repel the atlantic at all from all the other models as well when looking at that set!!

It may end up being that way - it is a legit possibility of course. I wouldn't bet against it being far too progressive though.

Edited February 5, 2021 by Paul

[SP1986]

 

Some current model facts to start the morning

The models have generally, up to this point modelled some kind of breakdown.

The cold spell however, has not started yet.

There is a fair amount of snow modelled in at this stage which should please the masses.

There is no widespread evidence for an undercut yet.. but that doesn't mean it won't feature in future runs.

This is modelled as probably the coldest spell for about 3 years and possibly the snowiest spell for 8 years.

 

[radiohead]

Thankfully this is 240 hours away and likely to change! 

 

 

It does look increasingly likely that less cold air will begin to move in after 144 hours, but that doesn't mean there won't be further changes on the models before we get there. 

 

[Chesil View]

ECM starting to smell the coffee about how hard the block Will be to shift.

[offerman]

Morning
 

could it be possible that the Scandinavian High tilts after a week bringing more direct longer fetch Easterly north-easterly winds prolonging the cold spell and pushing back the Atlantic low pressure making it either slide or just stall ? 

[geordiekev]

6 minutes ago, JoeShmoe said:

Yes shows on ECM quite nicely and think UKMO would evolve to that as well, still -10 uppers over the NE of the U.K. at that point so frontal snowfall for north Wales , north west and northern England . Milder in the south by that time as the low pulls up warmer air from the south 

Yep ECM has the snowline pretty much just above sea level for NE right through till Sat 13th, so any precip from the (breakdown) low has potential to be alwight in my book

[TSNWK]

7 minutes ago, JoeShmoe said:

Yes shows on ECM quite nicely and think UKMO would evolve to that as well, still -10 uppers over the NE of the U.K. at that point so frontal snowfall for north Wales , north west and northern England . Milder in the south by that time as the low pulls up warmer air from the south 

I recall January 2013 where snowed with uppers around -2 in the south because the flow at surface was from the south east near continent..  I think there will snow further south at end of week if ECM verifies

[matty40s]

2 minutes ago, radiohead said:

Thankfully this is 240 hours away and likely to change! 

 

 

It does look increasingly likely that less cold air will begin to move in after 144 hours, but that doesn't mean there won't be further changes on the models before we get there. 

 

That means you will need sunblock out on the snow fields. 

[Paul]

Morning, a bit of tetchiness in here first thing isn't there. Please think calm thoughts before hitting submit!

Also, this isn't the thread for discussing met office outlooks. 

Edited February 5, 2021 by Paul

[carinthian]

Anyway back to the shorter more reliable time span, the chart below shows an interesting feature. That front across Southern Northern England could produce a prolonged snow event along the boundary zone as the very cold Arctic Continental flow undercuts. The fax charts seem to hold it in that location for at least 12 hours before sending southwards on Sunday.  See what the outer parameter results from the snow computer shows later this morning. Yesterday , it did flag up that zone. Could be an interesting day for snow predictions for this weekends event to unfold. Think quite an intense cold spell to evolve for you guys. How long ? Should get an update later from the team.

Good morning from a mild Alps.

C

[Daniel*]

Tmax Sunday - Thursday on ECM 00z the SE experiencing a continental chill, 5 consecutive ice days in places that’s extremely rare maybe not seen since 1991. 

 

[Tim Bland]

UKV now goes for 36hrs of continuous snow fall for parts of the south east from sat nigh to mon night ! Lots of showers elsewhere .

[Typhoon John]

33 minutes ago, Daniel* said:

Interesting those scandi heights are new, savage cold on Thursday on ECM 12z with slacker airflow would challenge February 2012 over snow fields 

If the block is a little stronger to the east we could see that low stall further west and send WAA up the West of Ireland which would help to reinforce the block. That would subsequently drag in the colder air over Scandinavian. That would be my preferred outcome. If it does try to come through you would expect it to disrupt more than is being shown.

[Kentspur]

2 minutes ago, Tim Bland said:

UKV now goes for 36hrs of continuous snow fall for parts of the south east from sat nigh to mon night ! Lots of showers elsewhere .

Absolutely stunning run and with ECM upgrading too surely were reaching a consensus on the jackpot zones Sunday-Monday BBC forecast looked awesome also mentioned it continuing into Monday which matches these charts pretty well!

Edited February 5, 2021 by Kentspur

[Tim Bland]

46 minutes ago, Daniel* said:

Only one thing from stopping us going into freezer again, and that’s those heights in Southern Europe some haven’t left it at this point. 

That and the ball of -40 air over Canada / NE USA dropping  into the Atlantic and sending the jet stream into overdrive. Take one or both of those out the equation and it would have been a very long cold spell ! 

 

 

Edited February 5, 2021 by Tim Bland

[MattStoke]

UKV has 500mm (50+cm) of snow for some spots in East Anglia and the South East. May be overdone (Although I find this model is one of few that normally under does accumulation). Quite feasible though that some spots could see a foot or more, but more widely probably 15-20cm across some eastern areas. Certainly, I would expect a good few cm for more eastern and central areas (and a few spots in the west) than this model shows.

Edited February 5, 2021 by MattStoke

[TSNWK]

16 minutes ago, radiohead said:

Thankfully this is 240 hours away and likely to change! 

 

 

It does look increasingly likely that less cold air will begin to move in after 144 hours, but that doesn't mean there won't be further changes on the models before we get there. 

 

Oh no not another day 9 / 10 chase  

[bluearmy]

16 minutes ago, Broadmayne blizzard said:

ECM starting to smell the coffee about how hard the block Will be to shift.

The last three ops have been v unconvincing regarding pushing the Atlantic though - funnily enough, this run is the most enthusiastic by day 10 

15 minutes ago, offerman said:

Morning
 

could it be possible that the Scandinavian High tilts after a week bringing more direct longer fetch Easterly north-easterly winds prolonging the cold spell and pushing back the Atlantic low pressure making it either slide or just stall ? 

It is

3 minutes ago, beefy201 said:

Yes the SE is going to get buried .... cold and windy most other places with occasional wintry flurries 

Somewhere may well be but the ‘whole se’ ???

[Chesil View]

Looking at the ECM progression I still think there's time and room for some westward correction and  more of a  sliding scenario on the low at 144.  This set up is very reminiscent of seventies and eighties forecasts that would push lows and fronts in only to slide them at T24

[Chesil View]

6 minutes ago, bluearmy said:

The last three ops have been v unconvincing regarding pushing the Atlantic though - funnily enough, this run is the most enthusiastic by day 10 

It is

Somewhere may well be but the ‘whole se’ ???

And if this one has been the most enthusiastic would imagine there must be a good few ensembles that slide it.

 

Hence the Meto not talking about a 'possible' milder interlude until after the 18th Feb.

Edited February 5, 2021 by Broadmayne blizzard

[Tim Bland]

Here’s the Euro 4 take on sat night / sun morn. This is just 12 hrs into that low parked in the south east.. it could sit there for another 12-24hrs after so these totals could be at least doubled !