Model output discussion - 5th December 2016 - Into Winter we go

[feb1991blizzard]

That is run of the century, comparable to Jan 1987 in my opinion, its not just the 850's, notice the insanely low 500mb heights and curvature in the surface isobars, not to mention that blizzard small low, PPN type charts are useless usually but on this occasion, they probably fairly accurately measure the impact on this occasion, make no mistake, the words 'Contingency'  'and planners' should not be understated if that run came off, an absolute stunner!!

[stewfox]

11 minutes ago, Steve Murr said:

Ha -17c in London. That would be a shock to everyone..

whats caused this upgrade i know still FI , the low in Spain better amplification ??

Edited December 29, 2016 by stewfox

[Southender]

Lol. This GFS run will now go down as "That GFS" lovely to look at but of course it's only downgrades from there unfortunately. A watered down version would suffice.

Edited December 29, 2016 by Southender

[Ben Lewis]

6 minutes ago, Steve Murr said:

Ha -17c in London. That would be a shock to everyone..

What a shame that is over 2 weeks away.

Would love to experience that here in the SE compared to the mild dross over the past few winters.

Steve, I always remember you saying on years past to completely ignore the GFS 06z, infact 'bin it' were your words. Does this still apply or has the run improved over the past couple of years?

 

[Snowmaggedon]

Is it safe to dust off those sledges yet?

The cold seems to be firming up in the last 24 hours or so going by the comments from folk on here and Twitter. Bring it on!!!

[SMU]

11 minutes ago, stewfox said:

whats caused this upgrade i know still FI , the low in Spain ??

Well theres 2 levels really -

1 is the longwave pattern building at 144 creating the big high pressure moving NE at 192

then the shortwave pattern between 216 & 384 is PERFECT in terms of allignment for the UK - with another blizzard arriving at 396 from the SW

chances

1) 50%

2) 5%

S

[Man With Beard]

15 minutes ago, karyo said:

Exactly! This is similar to That ECM from 2012!

It's better than that, honestly. It's on a 1947 scale.

[radiohead]

-21 in Scotland...

[Methuselah]

Even though the bulk of any deep cold is way out there in La La Land, the onset of the cold itself (6/1/17) is quite close to the edge of 'the reliable'?

[gottolovethisweather]

19 minutes ago, chionomaniac said:

If I could programme a snow and cold lovers run into the GFS then the FI of the 06Z would be pretty much it for a perfect scenario. Pity it's FI really.

Welcome back and yes indeedy Chiono. It's only FI for another 4-5 days, and if such charts remain in the outputs by then, even I might start RAMPING.  Cold (Maxes 4-6c below average) now, a briefly milder blip (Maxes near average) by the weekend. Beyond this into the first week of January, a most intriguing synoptic pattern with cold/mild air battle going on during the best part of the week. By next weekend (D9/D10), we all could be plunged into the freezer with deep cold around, with a high probability of snow around and potentially damaging frosts.

[Long haul to mild]

Unbelievable run from the GFS. Wonderful to look at; the excitement only tempered by the fact that all the action is in FI and the chances of it coming off like that are very small.

However, the fact that an operational run is showing those kind of conditions at all should be cause for some cautious optimism about cold and snow prospects for January,

[chris55]

The key to getting the high to build north initially is the "gap" between the Azores low and lows to our north, if the Azores low stays far enough west of our high  that allows the other high to join it ahead of the Azores low and that creates the block.

UKMO has the Azores low pushing through and that not what we want to see.

GFS vs UKMO at 144

[Ali1977]

Great support from the control and the ENS to 174

[SMU]

Big big swing to ECM profile in the GFS 06z mean- there will be I think at least 6-7 sub -10c runs

00z 180 first v 06z 174

 

[pip22]

Matthew Hugo ‏@MattHugo81

Actually scrap that last tweet, how's this one instead?...Surely a 06Z GFS outlier on the way here. #deepcold

[Allseasons-Si]

Morning everyone

no KABOOM from you Steve murr!

510 dam or less covering most of the uk by 276hrs,that astonishing

 

[northwestsnow]

1 minute ago, Steve Murr said:

Big big swing to ECM profile in the GFS 06z mean- there will be I think at least 6-7 sub -10c runs

00z 180 first v 06z 174

 

Yes steve, would want to be seeing meto upgrades over the next 48h..

[Summer Sun]

Cracking mean at t180 certainly growing support for a colder outlook into Jan

 

Edited December 29, 2016 by Summer Sun

[PersianPaladin]

06z....

[markw2680]

Even a watered down version of that and we'd all be happy I'm sure

[northwestsnow]

[bluearmy]

1 minute ago, markw2680 said:

Even a watered down version of that and we'd all be happy I'm sure

A watered down version would have to be 10 degrees warmer ...........

[Catacol]

3 hours ago, knocker said:

That's one theory. Another would be that the ridge is quite strong from the south west up to Iceland which stops any great eastern movement of the southern arm of the jet and most of the energy is thus directed around the north of the ridge thus nudging it east and curtailing it's development north

I would suggest that this interpretation rather goes without saying. Those with an eye on GLAAM and the MJO profile have said time and again that transition to a Nina atmospheric signal makes pulsing ridges with the jet riding over the top the form horse and all the recent composites put up for discussion can be achieved with this scenario and without any deep cold draw from the east. However Steve's take on it is both possible and also more to the liking of those on this forum looking for wintry outlooks. The uk default westerly pattern with a jet less inclined to dive south is an option on the table is an omnipresent reality.

Are there any signs that we can lower heights to our south sufficiently to draw the cold air westwards and encourage the jet to hammer south? Not screamingly... but they are there. A growing wave 1 Asian spike is going to impact on the vortex I think, and the amplification of the MJO is beginning to build as we look to move out of the COD. The Atlantic has been very subdued all season now, and as we move towards the traditional reduction in Atlantic energy the chances of splitting the jet coming off the Eastern seaboard increase.

It is a close call - not so much in the short term where an undercut looks unlikely first time around... but the Nina imprint will encourage renewed Atlantic ridging especially with the forecast strength of the North Pacific ridge for an extended period. Net result? Default jet over the top always a player... but as each successive ridge pulses north the chances of splitting the energy increase.

After a disappointing December and the sobering reality of the loss of MJO support for high lat blocking the signs are definitely looking up. I am becoming increasingly interested in the latter 2/3 of the month. More detailed analysis with accompanying charts I'll do later today.

[Pembroke Dangler]

Could be having markets on the Thames like the old days if those temps projected by the 6z come off brutal cold and proper ice days with a good few feet of snow in higher places and a foot or 2 in lower areas and not a sw wind in sight. 

[karlos1983]

Dutch ensembles look cold in the extended range 

womt be long until we can see London