Model Output Discussion - The Start Of Winter

[Cheshire Freeze]

Something doesn't add up with those twitter quotes. Looking at the synoptic mean I'd say there would be a good 15-20 runs in there with ridging around Greenland.

[Cloud 10]

Much good discussion on ensemble mean's and anomaly charts today,so here are a couple from the ECM 12z at 240 hrs.

 

 

 

btw,Matt Hugo is on the wind up!!!

 

 

 

[nick sussex]

The ECM longer range ensembles are not bad, as for Matt H tweet either his account was hacked by Scrooge because I don't see how those ensembles for De Bilt could correlate with 51 members all with the same pattern to the nw,the wind directions clearly show that some pull a nw into De Bilt and then theres a large spread including north to easterly, you simply couldn't go from low pressure to the nw of the UK to east/northerly in one day for De Bilt.

 

Maybe Matt was at the Christmas Party and had too much mulled wine! lol

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

[Evening thunder]

  MattHugo81

Incredibly all 51 EC ENS members between 24th - 26th Dec develop low pressure to the NW with a mild SW'ly and not a hint of cold weather!

16/12/2014 20:30

 

ECM is notorious for op led ensemble bias. It tends to do this when there is uncertainty in the system. I would wait for at least two more runs before I took it at face value (two as it usually backs down in instalments).

 

 

That's odd as the mean is an improvement from recent ones I've seen with certainly some colder options likely in there for what it's worth

 

In comparison to recent times when the means have looked quite mild and I've thought there's perhaps been too much hope on a few ensembles/FI GFS op runs

 

Edit: see I was beaten to it several times lol

Edited December 16, 2014 by Evening thunder

[Man With Beard]

MattHugo via twitter also posted the following.

https://twitter.com/MattHugo81/status/544957954462863360

850s for Central England there are difficult to square with his earlier comment, seems to be a cluster from -4 to -7 by the 26th.

Yes the ECM ens is definitely not mild between 24th and 26th and is a White Christmas risk for half the country.

In fact, judging by the T240 chart (which was posted above), there seems a distinct possibility that even colder weather is waiting to follow behind a cold front which is staggering south-eastwards (obviously there will be individual runs that differ greatly).

All charts singing off the same hymn sheet for me tonight, what a difference from this time last week. But it will be a good few days before we see which individual solution wins out.

Once again, plaudits to the GFS for seeing the signal out at T384.

https://twitter.com/MattHugo81/status/544957954462863360

Edited December 16, 2014 by rjbw

[texel]

He may of been hacked as his twitter ban is in full progress for some reason.

[nick sussex]

Much good discussion on ensemble mean's and anomaly charts today,so here are a couple from the ECM 12z at 240 hrs.

 

EDH101-240.GIFEDH100-240.GIF

 

 

btw,Matt Hugo is on the wind up!!!

 

EDH0-216.gif

I've issued a banning order. Under the Cruelty to Cold Lovers section of NW rules! lol I thought I smelt a rat , Matt you naughty boy!!!!

[Mucka]

It just not seem plausible that every ensemble member would go for the same mild synoptic for around 10 days with so much uncertainty and it makes even less sense when looking at the mean anomaly chart for that time-frame.

Anyway, here is a snapshot of ECM forecast mean pressure anomaly day 10.

 

Edited December 16, 2014 by Mucka

[chris55]

First post in a while, at face value the ops this evening look better with regards to a potential colder spell than I've seen so far this winter. Will be interesting to see how things unfold around Xmas and beyond

[LomondSnowstorm]

Something doesn't add up with those twitter quotes. Looking at the synoptic mean I'd say there would be a good 15-20 runs in there with ridging around Greenland.

 

The mean anomaly chart looks even better for Boxing Day, with even a split flow in the mid Atlantic, which there wasn't on the GEFS mean:

 

Given that a few must just blow the ridge away completely it's a fairly decent set of ensembles.

[Nick L]

The ECM longer range ensembles are not bad, as for Matt H tweet either his account was hacked by Scrooge because I don't see how those ensembles for De Bilt could correlate with 51 members all with the same pattern to the nw,the wind directions clearly show that some pull a nw into De Bilt and then theres a large spread including north to easterly, you simply couldn't go from low pressure to the nw of the UK to east/northerly in one day for De Bilt.

 

Maybe Matt was at the Christmas Party and had too much mulled wine! lol

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

No idea what that tweet was about. I'm looking at the EC clusters and it's predominantly north-westerly for Xmas Day. All clusters going for cold or average, nothing mild.

[Cloud 10]

He may of been hacked as his twitter baning is in full progress for some reason.

 

Desperate measures by Ian Brown perhaps?

[summer blizzard]

Snow event for boxing day from the parallel. 

 

[texel]

Who knows lol!

Who knows lol!

[Thunder Snow]

Could be some pretty

 

13:00 on Christmas day sees some small amounts of snow for higher parts of Scotland and ROI

 

 

19:00 now this is where it gets interesting keep an eye on north Wales the highest depth is 5cm (just over an inch)

 

 

Now by 01:00 just look how much its increased its gone from 5cm (1inch) to 18cm (7inches) in just 6 hours! snow area starting to widen as well

 

 

Onto 7am boxing day and the totals keep on mounting now upto 25cm ( 9 inches) for north Wales and upto 5 inches for other parts of England

 

 

The final chart I have is at 13:00 and the totals keep on rising 28cm (11 inches) for parts of North Wales and upto 19cm (9 inches) for parts of Northern England

 

 

A clear difference in temperatures for the UK as well below zero in Scotland and double figures for parts of the south and south west

 

 

Same on boxing day at 13:00 the north is around or below freezing whilst parts of the south and south west are in double figure

 

 

Come on just Alittle further North, are these snow depths for higher ground or lower levels to

[texel]

Looks good but wont happen that way.

[IDO]

No idea what that tweet was about. I'm looking at the EC clusters and it's predominantly north-westerly for Xmas Day. All clusters going for cold or average, nothing mild.

 

  MattHugo81

For those discounting earlier tweet regarding all 51 EC ENS members find attached graphic for the 25th... http://t.co/rCG4umaTj8

16/12/2014 21:18

[Vorticity0123]

For anyone interested, an in-depth post about some indices (GWO, being the global wind oscillation, and the MJO), and their relation with the weather at our latitude and longitude, can be found in the In Depth model discussion part:

 

https://forum.netweather.tv/topic/76236-in-depth-model-discussion-and-summaries/page-11

[Love Snow]

@MattHugo81: Even I'm shocked at such a divergence to be honest. There is just no blocking over E Canada/Greenland on the EC ENS at all.

[texel]

must be shocking then if he's shocked!

[damianslaw]

No idea what that tweet was about. I'm looking at the EC clusters and it's predominantly north-westerly for Xmas Day. All clusters going for cold or average, nothing mild.

 

Perhaps a simple typo error instead of 'S' he should have said 'N' i.e. NW. Yes the clusters don't show mild for the Christmas period - indeed a classic ridge to the west, trough to the east with the UK sat on the cold side of the trough.

[bluearmy]

having digested the 12z ens ad nauseum, am i any the wiser?  well it seems that we remain uncertain re the xmas/boxing day period. that should become rather clearer over the next few runs. looks like a cool norwester with a decent chance of wintriness the further north you are.  beyond that, the weekend looks like the best chance for snowfall as we see the scandi trough extend southwest across us with amplification mid atlantic. any number of solutions for the detail but i expect to see a decent cluster of cold london member later. post day 10 and things become tricky.  ecm extended shows the atlantic high sinking southeast and mobility returning. im sure there are quite a few clusters in there, some of which maintain the cold. naefs looks unsure as to where it wants to go.  extended ecm does send the main pv back from the siberian side to the canadian which is always a sure sign of atlantic mobility. however, to mw, there appears plenty of space for a ridge to our nw to deflect that mobolity south as i mentioned earlier.

 

finally, for those of a cold disposition, i attach two charts from NOAA cpc re the day 8 and day 11 gefs ens mean anomolys and analog years.  i expect a few of you might want to check what followed those dates...

 

                         

 

tbh, they sort of surprised me a bit. they look a bit progressive with the dates they are centred on. anyway, they do look quite a fit for some of the LRF's.

[chionomaniac]

  MattHugo81

For those discounting earlier tweet regarding all 51 EC ENS members find attached graphic for the 25th... http://t.co/rCG4umaTj8

16/12/2014 21:18

It would appear that that cluster representative is not as good as it could be, and the SW shown there does not take account of the cold air already in position. #ECMclusterfail

[Frosty.]

As ensemble means go, and considering it's covering the christmas period, I think this from the Ecm 12z ensemble mean will please many coldies since it indicates cold and showery weather with snow in places and widespread frosts...considering how abysmal the last 2 or 3 festive seasons have been from a cold perspective, this one could be shaping up to bring the uk a cold plunge with snow in the forecast later next week, earlier further north..I can wait a bit longer for siberian cold, the arctic will do for now

[nick sussex]

  MattHugo81

For those discounting earlier tweet regarding all 51 EC ENS members find attached graphic for the 25th... http://t.co/rCG4umaTj8

16/12/2014 21:18

Yes but that just shows one member number 42 and its simply impossible for all 51 members to show the same pattern to the nw and then suddenly develop into whats shown on De Bilt from the 27th.

 

Wind directions give the game away, we need to move on from Tweetgate, someones either hacked his account or he's been abducted by a mild loving alien.