Model Output Discussion - The Start Of Winter

[mushymanrob]

And Ian kindly emphasised that the block scenario was starting to show up right at the end of the time period, not next couple of weeks.

Wait and see if models start to pick up signals over next few days runs i guess.

Oh don't get me wrong, i wasnt dismissing the potential beyond what the models are showing, but it was the current models i was referring to.

[mushymanrob]

Correct rob - you cant. Neither can we. MOgreps and ecm stamps are for the lucky few!

Oh, and blocking South of our latitude wouldn't preclude a westerly

Id have thought blocking to our southern latitude would most likely lead to milder conditions as a westerly over the uk would probably have southerly sourced air. The gfs in fi has dropped a few solutions like that recently.

[johnholmes]

And what do the anomaly charts show, are they changing or remaining with what the majority have been showing for a week or so?

here are the last outputs.

ECMWF-GFS, and they have had differences with one another over the last few days but the general theme has been what they suggest this morning. The upper trough is the dominant player, okay it is a mean, and there will be some mainly slight variations day to day possible. However the overall idea of a 500mb flow from west to WNW as a mean has not changed for some time.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

and the NOAA outputs, not totally in agreement on details but again the idea of a 500mb flow from the Atlantic, sometimes about west sometimes further north of west has been the pattern for a good many days.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

On none of the 3 above has there been any marked change in pattern/wavelength well west of the UK, western Atlantic across N America into the Pacific. Thus the pattern, with minor variations I mentioned for days taken out of the mean, is and has been set for some time. Until a marked change occurs in the major wavelength of the upper air pattern, not yet showing on any of the above 3, then the probability of something major say a deep cold air penetration of several days or more is unlikely. We have to take what Ian has posted from the senior man at Exeter, see below

Let me cite the Deputy Chief directly (from briefing issued this morning, based on 00z suites), to clarify exact phraseology:

"....postage stamps from both EC and MOGREPS-15 are now showing some waning in the strength of W’ly progression, with a minority of members (~40%) hinting at blocking across the Continent".

as our only scientific outlook beyond the 15 day time frame. Just what the above means in terms of where the blocking will develop, 55N, 50N, or further north or south, and how far east, is open to conjecture, so anyone making a suggestion might be correct from what UK Met are seeing.

Patience is the name of the game, it is after all only 8 December, some of you have already seen white falling from the skies, probably more will do so in the next week but a countrywide snow event is highly unlikely on low ground I would suggest as a sensible idea to accept.

Edited December 8, 2014 by johnholmes

[MR EXTREMES]

Let me cite the Deputy Chief directly (from briefing issued this morning, based on 00z suites), to clarify exact phraseology:

"....postage stamps from both EC and MOGREPS-15 are now showing some waning in the strength of W’ly progression, with a minority of members (~40%) hinting at blocking across the Continent".

yes the models are showing a clear indication of perhaps a block in the worst place possible if cold is whats wanted euro heights not scandi heights.

like this 

[Paul]

The GFS para is starting to roll again now after it's few days off. 

 

http://www.netweather.tv/index.cgi?action=gfs-update-2014;sess=

[frosty ground]

Id have thought blocking to our southern latitude would most likely lead to milder conditions as a westerly over the uk would probably have southerly sourced air. The gfs in fi has dropped a few solutions like that recently.

Hence why Blocking to our south wouldn't preclude a westerly........

[MR EXTREMES]

i could not make it up nice heights building of the eastern seaboard of the united states plus ridge trying to exert its influence into scandi area well were see its only one run but all happening pretty quick but im still skeptical of anything good for coldies.

 

but now ive just seen the 96 hr omg its looking better but will it carry on

[MR EXTREMES]

states enjoying heatwave whilst were on the chilly side for now

[No Balls Like Snow Balls]

i could not make it up nice heights building of the eastern seaboard of the united states plus ridge trying to exert its influence into scandi area well were see its only one run but all happening pretty quick but im still skeptical of anything good for coldies.

 

but now ive just seen the 96 hr omg its looking better but will it carry on

The P GFS run is even better IMO. Only 84 hours out, so would like to think things are not going to change much LOL.

[MR EXTREMES]

surely wave activity can resume into the strat and the activity coming from the scandi side sure this will aid strat warming.

[No Balls Like Snow Balls]

Some snow for the Midlands North on Friday, Snow even into parts of the SW & SE possible later Friday.

Edited December 8, 2014 by No Balls Like Snow Balls

[easton888]

I'm trying to remember, did we see ANY snow charts for the SE last winter?

[MR EXTREMES]

certainly not mild cold holding on nicely although the heights out to our west pushed back south a bit but still a far better run although a sign that a surface low is starting to take affect over in the states although not a massive feature.

still cold country wide at t144 coldest air in the southeast.

hope this can lead to something exciting 

[Frosty.]

Quite an impressive winter storm for northern UK this week and as winds eventually veer Northerly the snow line will drop with snow to sea level across at least the northern half of Scotland by Friday, really building up and drifting on high ground. Looking ahead, we could do it all again next week with lots of thundery wintry showers with snow on hills, especially further north and night frosts with icy patches but with slightly milder wet and windy spells inbetween..much as this week...boring it aint :-)

[Matty M]

GFS doesn't make much of the potential storm but obviously UKM does, cannot see the 72/84hr frame, but would be interesting!

 

[MR EXTREMES]

 

if the low to our north could just drop a little southeast into europe then we could safely say its full steam ahead would love to see heights drop into europe to the south and southeast of us.

[Mucka]

GFS (p) and UKMO in broad agreement 120 with GFS op still phasing energy earlier leading to a flatter pattern and stronger Azores ridge later. Think of it as battle of the bulge 

 

 

If UKMO is right and to a lesser degree GFS (p) we get another shot transient cold in 7 days time or so but if GFS is right then we just get wet and windy.

Edited December 8, 2014 by Mucka

[legritter]

Dont gang get too hung up over the possibility of high pressure setting up over central or southern europe ,this If it starts to show up more over the coming days on our available models will only be an attemp by the computers to try and locate the most likely area it will have its centre ,and at this range expect large swings ,it could of course go our way and finish up in a favourable position further north .[ fingers and toes crossed ].we are having just what we wanted some good looking charts ,snow for some ,and i,m expecting some surprises to turn up every time our friend the Fax charts are updated .Some interesting weather more akin to WINTER ,beats mild mush anyday ,tonights ECM eagerly awaited catch you up later ,  

[MR EXTREMES]

 pressure building into the heights to our sw or west the angle looks pretty good come on se movement of low pressure then the flood gates open from the arctic as it stands still chilly right out into fi

cold reload from the nw in the later stages of the gfs run the gfs para not far of the same best run in a few days 

not bad for now will it be there tomorrow or wed 

Edited December 8, 2014 by emotional rollercoaster

[nick sussex]

I think the UKMO might have to write a book on false dawns or output that lasts maximum of 12hrs before imploding! Putting aside my obvious irritation with the model, it shows heights lifting out of Greenland as early as T144hrs which is in stark contrast to the GFS and the return of the prodigal son GFS P.

 

It also develops a low near Genoa so overall if you had a choice of outputs and by some miracle the UKMO was on the right trend at T144hrs you'd go for it as the GFS's are pretty underwhelming at T144hrs both over Greenland and further upstream in the USA.

 

From a cold perspective at T144hrs then so far UKMO best, GFS P less good, GFS dismal.

[MR EXTREMES]

could the little kinks in the low pressure to our nw be a forming depression ready to dive southeast on this chart and lower heights to our direct south although in the very depths of fi.

im pleased with the gfs runs tonight watch the ecm throw a major spanner in the works dont even want to see the gem im hiding behind the sofa when watching future runs.

[Mucka]

Sorry ER but here is GEM 

 

Not to worry it is better upstream than last nights horror show at least

 

 

Though it is unlikely to get coldies pulses racing.

Edited December 8, 2014 by Mucka

[Paul]

Latest from Jo - obviously a lot of looking further ahead for cold potential in here, which is fair enough as a lot of people are interested in it - but some really severe weather possible in the shorter term

 

https://vimeo.com/113920563

[Summer Sun]

GFS P is back and we can now see the snow depth in closer detail

 

By 19:00 on Saturday some high parts of western Scotland have around 1ft of snow with 6 to 9 inches widely the further east you go in Scotland the less snow. Higher parts of England and Wales have around 1 to 3 inches

 

 

24 hours on and the snow depth is fairly steady though western Scotland does start and see some melt with the highest totals down 5cm from 33cm to 28cm

 

 

Now as we move on another 24 hours to December 15th the snow is continuing to melt away with the highest amounts down to 23cm (9inches). Not much left for England and Wales either

 

 

As we move on another 24 hours to December 16th another 3cm is lost from the highest totals which is now down to 20cm (7.7 inches). Amongst the losses it should also be said that the totals over the Cairngorms remain fairly steady from Saturday

 

 

Now we move on to the 17th and another 2cm is lost from the highest totals which now has it down to 18cm (7.3 inches)

 

 

The final chart takes us to 13:00 on the 18th and as we can see some snow is starting to fall again for parts of England, Wales, southern Scotland, Northern Ireland and the Republic. The highest totals in western Scotland see a slight increase to 19cm which is around 7.5 inches I think

 

 

So a fairly wintry spell coming up some rain tomorrow for western Scotland will see a slight melt but colder air rapidly moves back in from Wednesday turning any precipitation back to snow for Scotland and the northern Hills some of this may also fall as snow to lower levels at times during the next 10 days.

 

Although we see a slight melt in western Scotland totals remain high with the snow never falling below 6 inches for the highest parts and right at the end we see a slight gain as the air begins to turn colder again running the normal GFS P on further plenty more snow is on offer which is more than we had last December

 

PS

 

I can't post any charts between today and 01:00 on the 13th as they are not working so please don't think I've just ignored those days

 

For those in higher parts of Scotland enjoy the snow over the coming days if its your thing and hopefully lower parts of the UK and Ireland will join in as the days progress

 

Edited December 8, 2014 by Summer Sun

[Mucka]

Just for fun 

 

Anyone order a channel low and Southern blizzard?