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

[I remember Atlantic 252]

still looks decent on GFS, thicknesses okay, wind direction looks okay, but could do with this runner further South, as it's hill north event only, on this track

[Timbo]

please take note

possible tidal surge on Thursday / Friday, the low pressure in the North sea will push the surge South coinciding with very high tides.

If this happens i feel Norfolk, Suffolk could be hit quiet bad.

 

[gottolovethisweather]

5 minutes ago, Timbo said:

please take note

possible tidal surge on Thursday / Friday, the low pressure in the North sea will push the surge South coinciding with very high tides.

If this happens i feel Norfolk, Suffolk could be hit quiet bad.

 

 

 

As with the snow predictions and even the depth of cold predicted by some in here, the models will be off at t+10,000 minutes which are the timescales people are discussing. I say relax, embrace the opportunities that look like being thrown upon us, could yet be a fascinating end to the next working week, with gales, rain, sleet, snow and hail showers and of course drier interludes ALL in the mix. What's the most solid model run of the lot telling us right now, the ECM 12z.?

Edited January 7, 2017 by gottolovethisweather

[knocker]

31 minutes ago, Steve Murr said:

Gone are the years where a polar low was a nowcast-

The GFS develops it @ 102 south of svalbard ( the kink north of 985 ) - you will note thats not a depression...

the 500MB temps are perfect @sub -40c

 

At the timeline I highlighted @ 156 the PPN field is a perfect comma shape

Note the same shape

best

s

I'm sorry but the kink at T102 does not become the low at T156. It gets quite quickly absorbed in the circulation of the main trough and a new low develops within the main circulation at T150. A brief look at the sequence whether the new is polar or not is academic at this range I would have thought.

Edited January 7, 2017 by knocker

[The Enforcer]

20 minutes ago, knocker said:

Two points. Where exactly has the Tm come from because from  where I'm sitting it looks very much like Pm. Of course eventually it undermine the cold spell (or at least could do,( rather depends on the track) but in the mean time you can get some significant snowfalls as the warmer air overrides the colder air in the lower and boundary layers.It's all academic anyway.

Assuming we are talking about the same Low, it develops on Friday in the mid Atlantic in initially +5c 850 air and moves around the top of the Atlantic High to cross the UK on Saturday. This type of feature seems to rear its ugly head amid much debate every winter when cold spells eventually materialise. I am always told not to worry about the mild sector, but the outcome is always rain. I accept that at this range, the Low may not materialise on this occasion.

Edited January 7, 2017 by The Enforcer

[booferking]

Ecm looking pretty cold 120hr.

Edited January 7, 2017 by booferking

[chris55]

Whatever happens regarding snowfall or the progression from here, Thursday will feel bitter with that windchill and -5 850s sweeping right down to the south coast, Brrrr

[SMU]

25 minutes ago, knocker said:

I'm sorry but the kink at T102 does not become the low at T156. It gets quite quickly absorbed in the circulation of the main trough and a new low develops within the main circulation at T150. A brief look at the sequence whether the new is polar or not is academic at this range I would have thought.

Your wrong knocker follow it down from 102

Edited January 7, 2017 by Steve Murr

[Singularity]

The cold air seems to be arriving ever sooner as the runs roll out, which lowers the odds of more than brief snow from the leading cold front but, I dare to wonder, what exactly made the 2004 'thundersnow' event what it was? Could the flow be clean - hence cold - enough on Thursday?

Oops, I've gone and put a lovely cat among the pigeons!

[radiohead]

Cold air coming in from the west on the ECM at T120. Uppers down as low as -9 in places.

[SMU]

People of NI !

The 12z ECM 120 has the coldest 850s over NI in a deep cold convective flow - circa -9c

anywhere above 100/150M & NW facing will get a pummeling -

AWSOME ECM COMING TONIGHT-

 

Edited January 7, 2017 by Steve Murr

[chris55]

At 144 ECM is looking excellent! Can we get the ridge to fill the gap? Plus troughs in the flow cant be discounted.

Edited January 7, 2017 by chris55

[northwestsnow]

3 minutes ago, radiohead said:

Cold air coming in from the west on the ECM at T120. Uppers down as low as -9 in places.

Wowzers thats a very cold thur and fri so those lucky enough to get lying snow thurs should keep it until saturday.

Nice thought for long suffering coldies..

[nick sussex]

Some quite large differences appearing upstream at T144hrs between the big 3. Both the UKMO and GFS have trailing shortwave energy along the eastern USA . The ECM doesn't have this.

[knocker]

8 minutes ago, Steve Murr said:

Your wrong knocker follow it down from 102

You cannot possible follow small perturbations forming and dissolving on that chart.and having looked at every 6 hour chart in the relevant time frame I am not wrong. I am quite prepared to hold my hand up when I am but not this time.

Edited January 7, 2017 by knocker

[Tristrame]

1 minute ago, booferking said:

Sounds good steve

 

1 minute ago, booferking said:

Sounds good steve

Most of that -9 is actually in co Leitrim and Donegal Republic of Ireland,only about a quarter of it is in NI

But that said if verified a lot of NI,Donegal,Sligo,Cavan Monaghan,Louth and Mayo would see snow in precipitation ,it's an upgrade 

 

[snowice]

2 minutes ago, nick sussex said:

Some quite large differences appearing upstream at T144hrs between the big 3. Both the UKMO and GFS have trailing shortwave energy along the eastern USA . The ECM doesn't have this.

Keep us up to date with NOAA please

[snowice]

Just now, Tristrame said:

 

Most of that -9 is actually in co Leitrim and Donegal Republic of Ireland,only about a quarter of it is in NI

But that said if verified a lot of NI,Donegal,Sligo,Cavan Monaghan,Louth and Mayo would see snow in precipitation ,it's an upgrade 

 

ECM is a cracker for Ireland

[Dancerwithwings]

The UKMO follows the GFS 174h - 180h with that low on the N'westly flow.

UKMO at 180h

Edited January 7, 2017 by Dancerwithwings

[chris55]

That Low to the west of Greenland looks most unhappy, can we get an easterly...... we'll see. It almost looks trapped between the Greenland shelf and the high to the west, at face value you'd think it would bring the high over the top? But I know its not that simple.

Edited January 7, 2017 by chris55

[radiohead]

ECM T168. Rain in the south. Snow in the north. But colder air moving down behind it. Could be a significant snow event for Northern parts.

[Tristrame]

Just now, snowice said:

ECM is a cracker for Ireland

It's not bad,I forgot to include Meath in the snow county list

coasts would see sleet but much of the counties mentioned are well inland,and far enough north to receive showers from the Northwest or North,they hit as far South as Dublin usually and much of the west too

[SMU]

19 minutes ago, knocker said:

You cannot possible follow small perturbations forming and dissolving on that chart.and having looked at every 6 hour chart in the relevant time frame I am not wrong. I am quite prepared to hold my hand up when I am but not this time.

Really- !

im not arguing - anyone that can see a screen can follow that wave in the 6 hour timeslots on the slowest setting I could do.

your just being obtuse.

Anyway- 

The ECM @ 168 has a significant snow event for the North & parts of scotland with the low sliding across entrenched cold air

probably the best chart of the winter if your in that locale.

 

192 ooohh yes - come to papa

Edited January 7, 2017 by Steve Murr

[nick sussex]

8 minutes ago, snowice said:

Keep us up to date with NOAA please

They expected trailing shortwave energy to slow down the clearance of a cold front eastwards which looks more like the UKMO/GFS. The ECM is much cleaner in its evolution. We might though be cheering on the ECM if it can squeeze some ridging ne at T192hrs.

Sell the GFS/UKMO buy ECM shares! lol

Edited January 7, 2017 by nick sussex

[radiohead]

12Z ECM taking another attempt at a ringing in FI? -10 uppers in Scotland.