Model Output Discussion 29th December - Into mid-Winter.

[Ali1977]

Colder than the 12z by Thurs and more snow showers over the UK looking at the latest charts - I think there may be a few surprises about as early as Thurs night going on this run, -7/8 uppers in Jan and anywhere can get snow, at any altitude.

Fri 0100 , aware these aren't accurate but definitely shows there is a chance of UK wide snowfall even if it is a light flurry in the wind.

Edited January 7, 2017 by Ali1977

[Jammydodger]

6 minutes ago, CreweCold said:

The Metoffice have been reactive rather than proactive IMO this winter- something I mentioned a couple of weeks back. I think this is due, and has been due, to the lack of steering via drivers such as the MJO. They're relying more on model output...which has been all over the show.

Yes reading the MO 16-30 day forecasts they have only ditched the idea of the easterly today(albeit a low, very low chance), even when there was no sign of said easterly on the models that we could see...Who knows?The easterly has just reappeared on the ECM yesterday and today into the far reaches but maybe we are just playing catch up to the pros..

 

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

FI  looking  interesting   to say  the  least!!!

[Spah1]

Why? 

[kumquat]

Typical shortwave drama southern tip of Greenland, as per usual.

Interesting to see how the 18z pans out.

 

[Ali1977]

3 minutes ago, kumquat said:

Typical shortwave drama southern tip of Greenland, as per usual.

Interesting to see how the 18z pans out.

 

Lows sliding down the west of the UK on Sat, now these could be very interesting if the cold uppers hang on, battleground snow with some big dumps possible I'd say.

Looks like a poor FI though, not following the ECM and the Atlantic stepping up a gear at 180

Edited January 7, 2017 by Ali1977

[Eskimo]

Snow for midlands next saturday 

[fromey]

Could theses short waves slipping down the west side of the uk be what John Hammond is on about for the south over the week end

[radiohead]

18Z GFS is an absolute mess...

[Weathizard]

Honestly I have no idea what the GFS is up too on this run, the 180 chart is simply bizzare there's so much going on it's difficult to even know where to begin!

 

[kumquat]

Yep -6 to -8 850s clearing the south coast at T+126

Can't sniff at that.

[nick sussex]

Amidst all the shortwave drama take away the bizarre goings on over the UK and this is a move towards the ECM upstream.

[PersianPaladin]

Any output after T120 should be considered for the bin.

[Ice Day]

4 minutes ago, radiohead said:

18Z GFS is an absolute mess...

Just about to post the same thing.  It looked ok up to about 144 then started wandering off aimlessly.  The differences run to run are ridiculous really.

[nick sussex]

You have to laugh amidst the utter chaos of the GFS 18hrs run its still desperately trying to develop a small ridge to the e/ne at T216hrs.

[pip22]

Still looking good to me.

Maxes are only 1 or 2C above freezing especially at Northern UK. 

Sub-zero as max in Scotland!!

Edited January 7, 2017 by pip22

[SMU]

Already even @5 days away we are homing in on the peak period of snow activity over the UK ( showers & trough features ) being overnight Thurs into Friday Morning-

The uppers are peaking at -9c but widespread there will be a channel of -8s & the Theta charts look to be around  10c ( the magical number )

This combined with dewpoints at peak ( 126 ) widespread -4c means that I suspect the 850-1000mb thicknesses will be well below 1290 DAM

The feature to watch of polar original is the ripple over iceland at 114 hitting NI 120 & mainland UK 126 

may well signifiy a dusting all the way down towards london with the max values hitting NI & the NW-

best

s

 

 

Edited January 7, 2017 by Steve Murr

[kumquat]

Absolutely ferocious in Newfoundland @ 192

[Jonan92]

Ensemble moyenne at 240h on the 23th of january 2012

OP

What happened in the end

 

[Ice Day]

At 234 it's pushing heights up towards Scandi.  Who knows where FI is going on this run, I think the pub run has found the 1982 bottle of whisky at the back of the larder!

 

[chris55]

GFS again develops that little Low from the energy between the Atlantic highs. And it's tracking slightly further west than the 12z. There is potential that such a feature could deliver some very good snowfall to some areas in the sweet spot! 

However as John Hammond said in that tweet above details are IMPOSSIBLE to decipher at this stage.

 

[Dancerwithwings]

Seen what i want to see regarding the GFS 18Z...forget all the drama into FI.....Thursday and Friday showing Snow for large parts of the UK...HAPPY DAYS..Nite

[johnholmes]

15 minutes ago, Weathizard said:

Honestly I have no idea what the GFS is up too on this run, the 180 chart is simply bizzare there's so much going on it's difficult to even know where to begin!

 

Well what is the main feature overall from its output.

Try splitting it into

1)Is it a cold run say out to 144h, or a mild one, or a mix, best not to go beyond other than a very broad brush idea perhaps

2) Is it mainyl anticyclone or trough dominated?

Once you have those two ideas fixed in your mind, what do you think you would expect from it out to 144h, generally for the UK and then for your area. Don't expect detail on ppn until it is down to no more than 24h often less?

[nick sussex]

You can look at the GFS 18hrs as having everything possible going wrong and yet somehow it still wants to develop a ridge to the e/ne. The key thing to look out for is the drop down point of the elongated PV, the earlier GFS 12hrs run had this much further east. As long as the PV remains elongated running north/south then you have to have a reaction downstream as that heads south. Any ridge to the east of the PV will get thrown ne'wards.

 

[kumquat]

8 minutes ago, Ice Day said:

At 234 it's pushing heights up towards Scandi.  Who knows where FI is going on this run, I think the pub run has found the 1982 bottle of whisky at the back of the larder!

 

The Hooker is in place but there are no props.