Model output discussion - Post SSW - Will it turn cold?

[Snowjokes92]

Well i think this period of model watching can easily granted historic due to the synoptics on the table and the record ssw and major model inconsistency recently. It does beg the question still to me. A number of gefs ensembles for example take 850s to -10 and around 6 or 7 go down to -15 around the same time. It makes me think that the very cold outcome is just as plausible. Are these more rogue runs sniffing something, that the other models havent worked onto yet? It is a modelling period which cannot be compared to previous events in the past. The models have never had to model an ssw on this scale. This makes me feel like we stand a good chance of further upgrades in the model output as we dont know how they are gonna handle this compared to other events. Maybe the upgrades will be brought foward or maybe it wont. Time will tell though and whatever the outcome, this period will be talked about for many years on here am sure.

 

Edited February 17, 2018 by Snowjokes92
Gfs links

[WalsallWeather123]

NAVGEM on board with the easterly too. Deep cold air headed our way

[Mucka]

1 hour ago, Catacol said:

So - Saturday evening thought. Over the last week or so the models have generally been playing catch up in getting a handle on the tropospheric response to a major arctic warming and significant reversal. We are still seeing winds in reverse. Human interpretation has significantly led the way.

Are the models likely still to be playing catch up? Is it probable that all algorithms continue to overplay the normal westerly pattern, and undercook the speed of cold air advection westwards?

Id say yes - possible. Some of the more extreme runs on show may actually be more probable than we would normally expect to be the case, and rather than expecting a watering down of the process I wouldn’t be surprised to see a watering up - if you see what I mean.

Current mean forecast for the reversal sees it in operation until 1st March

 

Next warning phase directed at the Canadian vortex visible above and about to start. There will obviously be varying effects at different heights over this period, but I wouldn’t expect to see any resumption in dominant westerly forecasting for around a fortnight. We might actually see rather more in the way of upgrades rather than downgrades this time around.

Can’t quite believe my thinking is taking me down this path. 

Always nice to hear an educated and understated ramp. 

[LRD]

6 minutes ago, Snowjokes92 said:

Well i think this period of model watching can easily granted historic due to the synoptics on the table and the record ssw and major model inconsistency recently. It does beg the question still to me. A number of gefs ensembles for example take 850s to -10 and around 6 or 7 go down to -15 around the same time. It makes me think that the very cold outcome is just as plausible. Are these more rogue runs sniffing something, that the other models havent worked onto yet? It is a modelling period which cannot be compared to previous events in the past. The models have never had to model an ssw on this scale. This makes me feel like we stand a good chance of further upgrades in the model output as we dont know how they are gonna handle this compared to other events. Maybe the upgrades will be brought foward or maybe it wont. Time will tell though and whatever the outcome, this period will be talked about for many years on here am sure.

 

Those ensembles aren't actually as good as I thought they might be. For coldies this really will be feast or famine. No middle ground or consolation prize. Will be fascinating looking back at this and see what went right and/or wrong

[LRD]

5 minutes ago, WalsallWeather123 said:

NAVGEM on board with the easterly too. Deep cold air headed our way

Excellent. I'm well chuffed that NAVGEM is on board

 

[The Eagle]

 

JMA 192, decent but 500 hpa height stubbornly high over us even at that stage. Cold air on the way though/

Edited February 17, 2018 by The Eagle

[Snowjokes92]

11 minutes ago, LRD said:

Those ensembles aren't actually as good as I thought they might be. For coldies this really will be feast or famine. No middle ground or consolation prize. Will be fascinating looking back at this and see what went right and/or wrong

I agree it will be memorable for either right or wrong reasons, but will learn so much from it.

 

 

 

 

 

 

 

Edited February 17, 2018 by Snowjokes92

[pureasthedriven]

13 minutes ago, BLAST FROM THE PAST said:

It will miss Redhill....? ?

BFTP

Document1.docx

Doubt it - but definitely Horley! ?

[ANYWEATHER]

Evening All! Well an Easterly looks pretty certain now from mid week onwards,but will the Easterly deliver? The deep cold gets to us at day ten but gfs goes to show how horribly wrong things can go .......any interest is still at day ten ...watch this space

[LRD]

1 minute ago, Snowjokes92 said:

I agree it will be memorable for either right or wrong reasons, but will learn so much from it.

 

Think these are 12z ecm means and wow they are pretty desent, notice the greens widening and moving north west at each frame!

Bloody hell, at this range they are stunning means. But aren't they from last night?

 

[Catacol]

36 minutes ago, Southender said:

Anyone concerned the coldest uppers could drift south of us as has happened so many times in the past? Or am I worrying too much? ?

If the block were to remain slap bang over the UK - then yes. But the wealth of data from all parts is strongly suggesting that this wont happen. Doesnt make it impossible - but right now just cant see all that cold ending up in the Med. As things stand, it is heading across western Europe.

[Snowy L]

5 minutes ago, LRD said:

Excellent. I'm well chuffed that NAVGEM is on board

 

Just wait until the BOM gets on board.

[Frosty.]

It's all coming together nicely according to the Ecm 12z..hope I'm not tempting fate by saying that but in the short term, a warm front pushing across the uk from the west should be the last warm front introducing milder air for a very long time!!..as it is, Monday looks the mildest day but it doesn't last, it gets squeezed by colder air spreading from the west and east by tuesday and after Monday it looks like becoming largely settled with sunny spells and overnight frosts away from the far NW...then hopefully the major cold will start flooding west next weekend with the first snow flurries affecting eastern counties.

[Snowy L]

1 minute ago, LRD said:

Bloody hell, at this range they are stunning means. But aren't they from last night?

 

Yeah they are from Friday. Mean out to 96h so far

 

[Snowjokes92]

1 minute ago, LRD said:

Bloody hell, at this range they are stunning means. But aren't they from last night?

 

Could be. My bad saw 12z on them and got excites. Oops lol. Might be actually ok when they do come out

[bradymk]

Lovely mean at 240!

[Snowy L]

ECM mean has the lows in the Atlantic pushed a bit further west than the OP at 120h

Mean                                                    OP

Edited February 17, 2018 by Snowy L

[Banbury]

Stating the obvious I know

For those who keep saying it’s always at D10 well the Easterlies have to be forecast at some point .

The Met mentioned Easterlies on Feb2nd and forecast them to arrive between 16th Feb and 2nd March , well they are slowly getting here . Let’s see how far out they are in 168hours . 

Good charts again today , we are slowly counting down . Let’s hope there is something special at the end of this rainbow 

Edited February 17, 2018 by Banbury

[Catacol]

25 minutes ago, Tamara said:

But this SSW is a significant specimen indeed, and no further deep analysis is needed. On that basis I will be taking this particular day 10 deeper cold rathe more seriously as a contender

The fact that Phase 2 marks the time when the strongest sibling vortex lobe starts to finally cave in after its winter rule, increases the chances of deeper cold air advection at that time-period not just because the block to the NE can start to orientate in ideal position as polar jet energy is finally being squeezed out, but because the chances of retrogression are also much higher so that at some stage re-loading deep cold has a heightened chance of finding out even this little Island.

 

Yes - spot on and agreed. Signal for retrogression is strong, assuming warming of the Canadian shard progresses as expected. It's been a long winter of near misses for the south - but whichever angle we look at the current data it is hard to find an outcome that doesnt result in a cold easterly. Snowy? Maybe.... :-)

How about this for a 10 day ensemble mean...!

 

[Snowjokes92]

I posted wrong ecm means a few moments ago, but the updated ones are fantastic!

[Summer Sun]

ECM mean has trended down a bit from the 00z more noticeable past the 25th

 

[Man With Beard]

2 minutes ago, bradythemole said:

Lovely mean at 240!

Quite a scatter though!! 

  

Very rare to see -13C 850s within the ensemble range (Worth noting that the shaded bit doesn't include complete outliers, so there could be runs that are colder still)

[radiohead]

Day 10 ECM ENS mean has -7 uppers in the east. Very impressive.

Now we just need to get this to 96 and not 240...

[SLEETY]

3 minutes ago, Summer Sun said:

ECM mean has trended down a bit from the 00z more noticeable past the 25th

 

Big swing to cold there,where do you find those charts I can never find them (

[Leon1]

why is it always day 10?!