Model output discussion - 1st December onwards

[Summer Sun]

Continued hints from the ECM ens that things will settle down for a time next week as the jet stream moves north, northern parts more at risk of some rain right the end of the run with the south and SE remaining dry but a welcome spell of drier weather for all of us

Edited December 9, 2015 by Summer Sun

[knocker]

21 minutes ago, Cleeve Hill said:

With ECM at 144 (where it is pretty accurate) next tues / wed shows something a bit different. No conveyor belt lows but a depression sat pretty central over England and a small high to its west. 

So I reckon temps below ave and something a lot more seasonal. 

Actually the ecm has the temps about 2C above average for England at T144. Pretty much above average for the whole run, quite significantly at the beginning. Scotland nearer average.

[Mucka]

1 hour ago, Redwood said:

Its depressing reading guys and gals.  Im having a break for a bit.  Maybe come back in a week or so and see if anything seasonal will pop out of the proverbial bag for Christmas, but I doubt it.  Thanks to all your efforts, especially Nick Sussex, John, Chinio, BFTP and Tamara (where is Tamara?).  I've learnt loads over the years following this forum, just never had the confidence to post.

 

You really should post your thoughts, many of us here have learned as we have gone along and are still learning.

One of the best things about his forum is that it is not exclusionary and there is a wide range of knowledge covering a lot of subjects related to the weather.

[ANYWEATHER]

21 minutes ago, Cleeve Hill said:

With ECM at 144 (where it is pretty accurate) next tues / wed shows something a bit different. No conveyor belt lows but a depression sat pretty central over England and a small high to its west. 

So I reckon temps below ave and something a lot more seasonal. 

Hi, ecm and gfs show low pressure in control over the Uk at this time period, perhaps nothing too mild with this set up. but certainly nothing too cold. Cheerless  weather under these conditions , and some folk will receive relentless rain

[Costa Del Fal]

3 hours ago, Cheese Rice said:

I think what some people seem to be missing that it may not be the rainfall totals but the snowfall amounts that would make the headlines.

 

The fronts as they push north are rapidly turning to snow...

 

http://modeles.meteociel.fr/modeles/wrfnmm/runs/2015120912/nmmuk-42-72-0.png?09-18 

 

 

Th NMM only goes out to 72 hr but when you run the sequence the freezing levels are quickly dropping as the band pushes north 

 

http://modeles.meteociel.fr/modeles/wrfnmm/runs/2015120912/nmmuk-37-72-0.png?09-18 

 

The 850's are around -2 and the lows buffet against the cold air 

 

 

Potential for some significant snowfall indeed, especially as the GFS suggests the fronts will struggle to make it past N.England 

 

 

A little bit ignorant don't we think? The rainfall will likely be causing further major flooding. That will rightfully make headlines more than snow IMO. Sorry to rant.

needless to say the models painting a worrying amount especially for north wales. The boundary of warm And cold surreally over the uk arm. Still time for shifts north or south though.

[cyclonic happiness]

Annoyingly, the Midlands doesn't even get enough rain to get excited about. I don't think I've ever been so bored with the model output as the past 2 years.

 

 

[Costa Del Fal]

8 minutes ago, cyclonic happiness said:

Annoyingly, the Midlands doesn't even get enough rain to get excited about. I don't think I've ever been so bored with the model output as the past 2 years.

 

 

No amount of rain is ever worth getting excited about for the potential flood damage it can do.

[Gavin Hannah]

Western America is getting a good soak just now from what I can see on the beeb weather, while the east coast is unseasonably warm.

 

And so begins the pub run.....

Edited December 9, 2015 by Gavin Hannah

[winterof79]

47 minutes ago, Costa Del Fal said:

No amount of rain is ever worth getting excited about for the potential flood damage it can do.

The Cumbrian fells which played a major part in the run-off of rainfall will have snow on for 2-3 days which can only ease the situation lower down

Scafell Pike Snow Forecast

Days 0-3 Scafell Pike Weather Summary:

Mild with heavy rain (total 37.0mm), heaviest during Wed night. Becoming colder with a moderate fall of snow heaviest on Wed night. Freeze-thaw conditions (max 6°C on Wed night, min -1°C on Thu night). Winds decreasing (stormy winds from the SW on Wed night, light winds from the SSE by Sat morning).

Days 4-6 Scafell Pike Weather Summary:

A heavy fall of snow, heaviest during Sat afternoon. Becoming milder with moderate rain (total 12.0mm) on Mon night. Freeze-thaw conditions (max 4°C on Tue morning, min -1°C on Sat afternoon). Winds increasing (calm on Sat afternoon, gales from the E by Mon night).

WedThursday 10Friday 11Saturday 12Sunday 13Monday 14Tue

http://i0.fast-sfc.com/images2/t_scotland-snow-sum12.cc23.jpg

Edited December 9, 2015 by winterof79

[Gavin Hannah]

While still a bit iffy looking, the cold air digs deeper into the Atlantic on the 18Z at about t.105 Low to the west is position further north. While not looking like producing anything like a miracle, the overall weather should be more seasonal at times. Big problem is going to be the rain fall.

[SMU]

Could be a pub run special tonight - maybe the GFS has been at the mulled wine...

note the more vertical allignment of the low in the atlantic - on the 12z it was strongly positive tilted...

 

Edited December 9, 2015 by THE CHOSEN ONE

[shaky]

Well well gfs looks very interesting at just 132 hours tonight!!arctic high digging into the uk from the north!!all in a very close time frame!!

[Gavin Hannah]

Here's yet another problem at t.135.... Captain Shortwave strikes again

Only positive I can see is that the HP to our north is more favorably aligned at t.147

Edited December 9, 2015 by Gavin Hannah

[knocker]

I believe the GEFS anomaly has already been posted so a quick look at the ecm. Classic NH set up at T240 with the trough mid Atlantic and HP to the east. some unsettled weather but mainly in the north where the temps around average but more settled in the south in the SW flow with temps quite away above average towards the end of the ten day period. A similar set up in the ext period except by T360 the HP N. America has tracked east to NE Canada and similarly the Atlantic has edged nearer the UK.  Temps still a little above average.

Chart weatherbell

Edited December 9, 2015 by knocker

[feb1991blizzard]

A better effort but I think we are just going to be thwarted by the low being ejected from the main area of troughing just to the west, its moving North East, we need it to dig South East.

[Gavin Hannah]

1 minute ago, feb1991blizzard said:

A better effort but I think we are just going to be thwarted by the low being ejected from the main area of troughing just to the west, its moving North East, we need it to dig South East.

 

I agree but the more favorable HP alignment to our north may drag it NW.

[feb1991blizzard]

Just now, Gavin Hannah said:

 

I agree but the more favorable HP alignment to our north may drag it NW.

It may just fill but then you still have the problem of the Euro heights - as I say though a much better run than earlier runs today.

[radiohead]

There are so many changes at the moment regard to that low between T72-T96 that it's almost irrelevant what happens at T150 etc.

Any Shannon Entropy updates from @fergieweather ?

[Allseasons-Si]

 

Well the pub run looks different @ 132 hrs with more of a negative tilted trough in the atlantic,and also  a NE wind showing up there in Scotland,and look north

the 18z gfsthe 12z gfs

also in the shorter term,it's not looking good for them up in the NW

 

 

[Gavin Hannah]

1 minute ago, feb1991blizzard said:

It may just fill but then you still have the problem of the Euro heights - as I say though a much better run than earlier runs today.

Plus the LP in the Atlantic can eject SW after SW if it chooses.... 

The more runs we get without the LP phasing in the Atlantic, the better but it's still by no means easy street to sustained cold.

[knocker]

The worry still remains how much rain these two systems deposit and where. The rainfall charts are useless at this range (or any range come to that) particularly as it's rather a complex set up so it's a matter of a watching brief at this stage.

 

Edited December 9, 2015 by knocker

[Captain Shortwave]

1 minute ago, feb1991blizzard said:

It may just fill but then you still have the problem of the Euro heights - as I say though a much better run than earlier runs today.

Oddly because of how the low is handled on the GFS, whilst it looks better the run is much milder, especially in the north and fronts succeed in clearing the north of the UK as opposed to the previous runs where the front stalls over northern England. This shown by the rainfall totals.

Wales has seen a significant reduction compared to previous runs (except the north west of the country). Northern England and Southern Scotland brought into the firing line.

The actual operational looks similar to the 12z GEM run with the strip of warm air separating the areas of low heights in the Atlantic and the main polar low heights.

Euro high still well in play, hence the mild surface conditions near enough throughout the run. Double figures in the south every day on this run (even Friday and Saturday).

[feb1991blizzard]

1 minute ago, Captain Shortwave said:

Oddly because of how the low is handled on the GFS, whilst it looks better the run is much milder,

Yes I wasn't really thinking of brief snow over the hills on Saturday, I was thinking more building the blocks for FI, anything in the very near future would be a massive bonus now.

[The Enforcer]

12 minutes ago, feb1991blizzard said:

A better effort but I think we are just going to be thwarted by the low being ejected from the main area of troughing just to the west, its moving North East, we need it to dig South East.

The jetstream forecast for that period seems to show a strong push to the south of the UK, so I don't see why a SE direction of travel for the low wouldn't be possible. It's such a small feature that I imagine it's position and intensity will vary dramatically from run to run. In the end, it may not even materialise.

[Gavin Hannah]

Low pressure setup here looking like taking most of the weather through the channel as apposed to through the UK, Subtle difference but could be something to watch as colder air to north starts to dig south further on.

 

Edited December 9, 2015 by Gavin Hannah