Winter Model Discussion 06Z 10/01/13>

[Jayces]

Hmm if the poster refered to E.Anglia, and streamers are from the Thanes south, looking at the fax chart I'm confused now lol,so basically nothing for mid norfolk then?? lol

Sorry was just giving an example of what one was, they can come from a number of places in the UK but I only know how the Thames one works having been under it.

The gist is the same if you are in a favourable location with a favourable wind off of the North sea and favourable temperatures as it's al about convection I believe.

Someone else can probably list the streamer locations in the UK and where they affect, the Thames one affects the Thames valley to the south of the Thames mainly and spreads SW from there affecting a wider area in a cone shape say from Brighton ish to Isle of Wight....or something like that.

[Panayiotis]

Hmm if the poster refered to E.Anglia, and streamers are from the Thanes south, looking at the fax chart I'm confused now lol,so basically nothing for mid norfolk then?? lol

No as its not a strong easterly, if it was a stronger easterly the wind would pick up moisture (more moisture is picked up when the difference between temperatures at 1500m and the sea is higher than 13C, therefore the air is more unstable causing moisture to evaporate), when this hits the colder atmosphere it condenses and freezes (clouds) these clouds are then blown onto the land causing snow showers. Edited January 10, 2013 by Panayiotis

[JP1972]

A streamer is something members in the SE often refer to when an isolated snow shower moves into the Thames.

I thought it was something the Mods had in their hands and twirled above their heads when a thread wasn't littered with off topic comments

[WillinGlossop]

In 2005/2006 we had snow on streamers for days here..... Most of rest of se england was sleet but we had heavy wet snow..... If it had all laid we would of had feet not inches..... It does come down with the right wind direction here..... Plus evaporative cooling can play its part whih i reckon will be a feature with ths weekend..... If the precipitation can make it this far and is heavy enough.....

[Chris W]

A great run from the GFS to put it mildly, or not mildly I should say! Leaving aside the consensus for a cold and potentially snowy weekend and whatever comes early next week, Thursday looks immense for battleground snow over the west.

I was confused as to why it was showing such a strong Atlantic when the SSW is in force and has the PV in disarray, but it seems to have come to a more likely solution given the prevailing analysis (strat thread, BBC, latterly Met Office) associated with the SSW, high-latitude blocking and its associated drawing of easterly winds that has been growing in volume for days on end.

[Severe Siberian icy blast]

Well just a quick one from me, very happy with the backtracking , just as I thought , also nice to see it picking up on greeny hights been a player again, I think once we get to early next wk we should start to see some amazing fi charts , I mean bigger and stronger blocking features than now , I think they are slowly getting to grips with what's been taking place in the strat.

See you all in the morning.

[london-snow]

Experts correct me if I'm wrong but a streamer is often linked to 'lake effect' snow and are enhanced by geographical features concentrating winds onto a particular area. For example the heavy London snowfall of Feb '09 was caused by a Thames streamer.

Correct mate,

There are a few different types of streamers that can set up but is dependent on uppers and wind direction and subsequent strength. In 2009 a thames streamer produced a foot to my doorstep although was followed by a quick thaw the following days. Somehow feel if a streamer was to set up in the coming days the thaw will be very very slow.

[SandraD77]

Grrr typical lil ole Ireland not invited to the snowfest yet again :-( Models starting to show some (relatively) decent consistancy, so looking like you Brits will be in for a winner if the models verfiy and I'll be delighted for you all if it does! Us Poor Irish who missed out last Feb, may have to hope for a later shot at a deeper cold period towards the end of the month!

[goosey007]

Ahh Predictive text at its best... But me a shovel whilst your there is that a dry patch over Steve m's house I see? Seriously though don't take much notice of these depth / precip charts at this range. Precip distribution with change massively run by run. It's the pattern that's important and thank god GFS came on board in the end!

more like my sausage fingers!! lol yeah i know this is away off its just good to see this in the charts at a relative close range ......besides snow is due monday night and maybe a little saturday night aswell so im confident of seeing the white stuff in the next week or so

[Jason M]

That was a very very cold run in high resolution. With so little wind and very cold temps aloft it would get very cold indeed over time.

In the east its also quite a dry run as far as I can see. Fergie has already been on tonight and said that the METO are not expecting deep driving snow in the next few days. I'm sure most will see snow and some places will get a good covering. We now look like we have got the cold, whether we get a lot of snow is still to be decided.

Let's see how things evolve in the morning as much yet to be decided. I'd personally like to see more of an easterly as this would give snow to the east as well.

Jason

[Kentish Snowman in Yorks]

Well I think we have now reached the stage where we can now relax a little in the knowledge that we know that a cold 'spell' is on the way.

How cold, how long and how snowy that spell will be is obviously open to conjecture, but I am just looking forward to how it all unfolds.

Taking the 18z op at face value (very dangerous I know!), it keeps the 850s at or below -5 IMBY from T36 out to the end of the high res output with countless snow opportunities, and with the majority of tonight's output showing a different variations on a similar theme, I for one will be enjoying this upcoming spell for all its worth.

Hell I may even wax my sledge!

[snowblizzard]

Virtually every morning this week we've turned on our computers and viewed the models with a heavy heart!

Usually resulting in massive disappointments due to back tracks or down grades!

Please tell me that's not going to happen tomorrow?

[TEITS]

Im sure some members will want an overall outlook of what the models are showing for this weekend into next week so here goes. Do not take as gospel though because especially from Monday onwards its still uncertain.

Saturday.

Rain in the S with snow on the N flank especially SE Wales/SW Midlands area. Those areas who are seeing rain could see this turn to snow before it clears S.

http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2013/01/10/basis18/ukuk/prty/13011218_1018.gif

Sunday.

Snow showers in E areas with areas such as Lincs/Humber look most likely to see heavier snowfalls although this could extend into Norfolk. Will add im not ruling out snow in other E areas.

Monday.

Rain moving E turning to snow across central areas of the UK and most probably weakening as it reaches the far E of the UK. The areas that could miss out on snow is possibly Wales, Ireland, SW England, W Scotland.

Into the rest of the week is tricky to predict. I would suggest remaining cold with the colder temps spreading back W. At the moment the SE could be the coldest part of the UK and snowfalls could occur spreading from the W across the UK.

Hope this helps.

[seabreeze86]

Good agreement for the shortwave to sink south east on the GEFS on the 18z.

[rory o gorman]

Grrr typical lil ole Ireland not invited to the snowfest yet again :-( Models starting to show some (relatively) decent consistancy, so looking like you Brits will be in for a winner if the models verfiy and I'll be delighted for you all if it does! Us Poor Irish who missed out last Feb, may have to hope for a later shot at a deeper cold period towards the end of the month!

dont worry about Ireland yet . get a pattern change like this in and im sure we will get hit .

[Slowpoke]

[excited 20 year old] hoping for blocking the scale of '63 [/excited 20 year old]

[Weathizard]

Looks a big improvement on the mean at 120, can't post charts but looks like mean is backing the SW moving S/SE.

Edited January 10, 2013 by Weathizard

[SP1986]

I have to agree about the cold temperatures, if it came off, they would most likely be similar to 2010, but I suspect this time more central west orientated... excellent for cold lovers, but an absolute disaster for agriculture and horticulture.

[SMU]

& so we talked about tipping points-

We discussed this morning the journey the GFS would go on this with the shortwave-

it would take 4 full runs to reach the Euros-

IIRC it was 00z ALL Easterly movement

06z slight energy SE- main energy East- still the same outcome- overrunning pattern

12z more & more energy moving south- tipping point but neutral signal now

18z Overiding signal moving south- well past the tipping point-- big change???

T 120 12z ensemble mean

T 114 18z ensemble mean- KPOW! goodnight GFS

S

Edited January 10, 2013 by Steve Murr

[BlueSkies_do_I_see]

Fantastic switch from the GFS model tonight, that definitely increases the odds of snow warnings being issued by the MET office before the weekend is out if the outputs do not alter. The MET office issued a Red Alert for snow at the beginning of Feb 2009 for the South East. I wonder if another is on the way?

[SandraD77]

dont worry about Ireland yet . get a pattern change like this in and im sure we will get hit .

Agreed, equally I'm along the same thinking as Peter O'Donnell, that the real cold will be end of Jan/Feb and I think we'll be in for something "properly" wintery then! Here's hoping anyways! All in all happier with the recent model upgrades!

[rory o gorman]

ens look mixed on the 18z . but some crackers, perturbation 6 is an ice age lol

Edited January 10, 2013 by rory o gorman

[mountain shadow]

Grrr typical lil ole Ireland not invited to the snowfest yet again :-( Models starting to show some (relatively) decent consistancy, so looking like you Brits will be in for a winner if the models verfiy and I'll be delighted for you all if it does! Us Poor Irish who missed out last Feb, may have to hope for a later shot at a deeper cold period towards the end of the month!

Your looking at the wrong models then Sandra.

Both tonights GFS and the ECM would bring plenty of snow it Ireland

[ChartViewer]

Hi,

Wonder who...last night when seeing the GFS carrying on with its shortwave mystery tour west to east felt the Euros would back down today...I must admit i thought wed be seeing a different outcome tonight so im well pleased at the output so far....any thoughts from others!....Including Steve!

Edited January 10, 2013 by ChartViewer

[EML Network]

Totally bonkers Ensembles, a large number are going for another Easterly Wednesday / Thursday ...in fact I'd go as far to say that the Operational will not by any stretch of the imagination be among the coldest members ...I am speechless !!

This being said, the GFS has modeled this whole episode poorly when compared to the ECM for example, and so any output it's showing currently really does need to be looked at with some scepticism.

What ever way you look at this, the cold looks set to last until at least Wednesday , so I make that 5 days minimum of cold and snow potential...and if the Ensembles are onto something , then we could be on the verge of something truly remarkable