Model output discussion - 5th December 2016 - Into Winter we go

[Iceberg]

Gfs is more progressive with its cold air on Christmas Eve. Colder and more precip = more snow 

[Iceberg]

Upto the reliable timeframe and gfs  has stuck with the 0z run almost perfectly. A 950mb Christmas Day storm brining strong winds to the uk and storm force to most of Scotland. With snow showers packing in behind during the day it self. 

[radiohead]

06Z GFS still showing a stormy Xmas Eve/Day  though the strongest winds confined mainly to Scotland and not as severe as previous runs.

[legritter]

well looks like first low on GFS is some 150 miles further north , but at 4 days plus still time for change ,Secnd low not updated yet but think this one will be the more active one .I was a bit disappointed with this mornings ecm but at this range it could be all change this evening ,perhaps Met off update soon can shed some light on medium range outlook ,medium as in 7/10 days ,will be interesting If they still mention high to our west , crikey what a roller coaster ,hope we can get a few cold shots soon ,cheers ,

[Sir Saats a lot]

Does anybody know if this Christmas period model output matches that of 1995. We have been having similar weather behaviour up here in Shetland. The Christmas period of 1995 brought some serious snow for us, 30 feet deep in places.

[northwestsnow]

4 minutes ago, Sir Saats a lot said:

Does anybody know if this Christmas period model output matches that of 1995. We have been having similar weather behaviour up here in Shetland. The Christmas period of 1995 brought some serious snow for us, 30 feet deep in places.

Nothing like what we have now unfortunately. 

Edited December 19, 2016 by northwestsnow

[northwestsnow]

Gfs6z, after a very disturbed christmas period turns on the blowtorch by the 30th with temps of 12 and 13 degrees widely.

Makes it to 14 by NYE but then a ridge builds in the Atlantic to shut the zonal train off!

Edited December 19, 2016 by northwestsnow

[NorthernRab]

11 minutes ago, Sir Saats a lot said:

Does anybody know if this Christmas period model output matches that of 1995. We have been having similar weather behaviour up here in Shetland. The Christmas period of 1995 brought some serious snow for us, 30 feet deep in places.

Hi Sir Saats and welcome to the forum! This thread is normally for discussing the model output (you can view the charts produced by these models through the links at the top of the website) - your question would normally go in another thread. There's a regional Scottish discussion thread you'll probably find helpful for such questions which you can find here: 

 

Re your question. The current pattern (picture below, right) is completely different on a hemispheric level to 1995 (pictured below, left). Notice the high pressure over Greenland which allows deep cold to push south over Scotland. I'd love to see a repeat of that (lows of around -22'C to -24'C in these parts) 

 

Edited December 19, 2016 by NorthernRab

[Dennis]

some of hope for cold 

[northwestsnow]

Yes 6z much better in FI as the high ridges to scandy, i fear its a mirage but coldies really do deserve a change of fortune!

[Summer Sun]

Strongest winds seem to be for northern England 1st then across Scotland

[Paul_1978]

3 minutes ago, northwestsnow said:

Gfs6z, after a very disturbed christmas period turns on the blowtorch by the 30th with temps of 12 and 13 degrees widely.

Makes it to 14 by NYE but then a ridge builds in the Atlantic to shut the zonal train off!

That's way out at T+264, and the fact it is completely different to the 00z run, I wouldn't worry too much

[Seasonality]

5 minutes ago, Dennis said:

some of hope for cold 

Yes, Atlantic ridging, something the Met Office are hinting at. 06z finishes with this mouth watering result. Yes, I know it is at the very edge of FI, but lovely to look at and dream all the same.

 

Edited December 19, 2016 by Seasonality

[northwestsnow]

1 minute ago, Paul_1978 said:

That's way out at T+264, and the fact it is completely different to the 00z run, I wouldn't worry too much

Well i like what happens thereafter Paul!! 

[Nick F]

Well, well at last Low-res/FI GFS op update showing more interest for coldies as major amplification upstream takes place, leading to ridge north over UK and Norwegian Sea, then into a Scandi High - which is less reliant on a troughing undercut across SW Europe from the Atlantic but more reliant on cold pool dropping down across Russia into Europe. However, with no height rises over the pole not sure how this cold so easily gets pushed down from the arctic into Europe.

I was thinking yesterday that it's been a long time since GFS or ECM gave coldies some eye-candy ... so long overdue. But being the depths of FI and no strong teleconnections signals other than GFS creeping into low amplitude 7/8 MJO phase, not sure this will appear again next few runs.

Otherwise in the reliable, 06z GFS op another conveyor belt of deep lows in high res - bombarding the UK with little respite between. One on Friday, which could be the second-named storm of the season (Barbara), then perhaps Conor on Xmas day. More lining up next week to make a move across the N Atlantic, though hopefully as suggested on a more northerly track.

Although Xmas Day low still looks worse for winds on GFS ops, Friday night's storm still needs to monitoring, as the models may not have the correct handle on depth and pressure gradients yet at this range, Friday's low could turn out deeper than Xmas day's low, certainly 00z EC was hinting at this. Strong 200mph+ jet and a lot unusually warm air being drawn into these lows emerging off eastern seaboard sourced from SE USA and Bahamas are a recipe for rapid intensification if phasing is favourable.

Given the v. strong W/NW flow in wake of Xmas day's low, should be less modification at the surface of air sourced from a frigid southern Greenland and Labrador than a lighter flow, so we may see snow get to lower levels in the NW in the evening when the cold air kicks in. Certainly blizzard conditions for the Highlands I imagine.

 

[carinthian]

8 minutes ago, Nick F said:

Well, well at last Low-res/FI GFS op update showing more interest for coldies as major amplification upstream takes place, leading to ridge north over UK and Norwegian Sea, then into a Scandi High - which is less reliant on a troughing undercut across SW Europe from the Atlantic but more reliant on cold pool dropping down across Russia into Europe. However, with no height rises over the pole not sure how this cold so easily gets pushed down from the arctic into Europe.

I was thinking yesterday that it's been a long time since GFS or ECM gave coldies some eye-candy ... so long overdue. But being the depths of FI and no strong teleconnections signals other than GFS creeping into low amplitude 7/8 MJO phase, not sure this will appear again next few runs.

Otherwise in the reliable, 06z GFS op another conveyor belt of deep lows in high res - bombarding the UK with little respite between. One on Friday, which could be the second-named storm of the season (Barbara), then perhaps Conor on Xmas day. More lining up next week to make a move across the N Atlantic, though hopefully as suggested on a more northerly track.

Although Xmas Day low still looks worse for winds on GFS ops, Friday night's storm still needs to monitoring, as the models may not have the correct handle on depth and pressure gradients yet at this range, Friday's low could turn out deeper than Xmas day's low, certainly 00z EC was hinting at this. Strong 200mph+ jet and a lot unusually warm air being drawn into these lows emerging off eastern seaboard sourced from SE USA and Bahamas are a recipe for rapid intensification if phasing is favourable.

Given the v. strong W/NW flow in wake of Xmas day's low, should be less modification at the surface of air sourced from a frigid southern Greenland and Labrador than a lighter flow, so we may see snow get to lower levels in the NW in the evening when the cold air kicks in. Certainly blizzard conditions for the Highlands I imagine.

 

Ay Nick, its a long time we have seen a chart like that. Probably would end up with a potent Easterly. However, as you say its a long way off and you real cold starved fans in Blighty will be very wary to get excited at this time, especially having been lead down the garden path so many times this past few winters. Shorter term, the Festive Period forecasting must be causing a bit of headache in getting it spot on, even in this daily time span.

 C

[snowangel32]

1 hour ago, Iceberg said:

Gfs is more progressive with its cold air on Christmas Eve. Colder and more precip = more snow 

My favourite kind of update, the gfs is bullish and having none of what the ecm is showing. Be great to get some insight from Fergie because this must be a nightmare to forecast even with it being only 6 days away.  

[knocker]

A Sidney chart. Not a lot of cold air around to be tapped into

[karyo]

2 minutes ago, knocker said:

A Sidney chart. Not a lot of cold air around to be tapped into

Even Greece has started to warm up after a very cold few weeks! Turkey though remains a winter wonderland.

[karlos1983]

13 minutes ago, knocker said:

A Sidney chart. Not a lot of cold air around to be tapped into

That's an anomaly chart showing 2-4 C above average. Still probably cold for west Russia and Eastern Europe.

luckily January looks colder, don't lose your winter coat just yet Sidney, you might freeze your knockers off! 

 

Edited December 19, 2016 by karlos1983

[snowray]

10 minutes ago, knocker said:

A Sidney chart. Not a lot of cold air around to be tapped into

mmm no not for us, but thats because its down there where it usually goes these days, you know, Turkey, Syria, Lebanon. Strange to see Greece missing out on the cold too though...

[Iceberg]

Gfs 06z ens show that the op run was pretty standard to be fair.  Some bring stronger winds some weaker but the pattern shown of strong to extreme winds, mild air and snow in pm air all over Christmas is represented in around 70-80% of members. 

[Methuselah]

Reasons for cautious optimism, on today's 06Z, I'd suggest? Possibilities seem to exist for either an easterly outbreak, a northerly outbreak or even, dare I say it - both... The only downside is that it's all so far out in La La Land, it'll have (as it stands) less than a 50% chance of verifying? Let's just hope it does!

[jvenge]

4 minutes ago, karlos1983 said:

That's an anomaly chart showing 2-4 C above average. Still probably cold for west Russia and Eastern Europe.

Depends on that mysterious definition of cold (different for everyone). It will still be jumper and coat wearing temperatures, shall we say.

1 minute ago, Ed Stone said:

Reasons for cautious optimism, on today's 06Z, I'd suggest? Possibilities seem to exist for either an easterly outbreak, a northerly outbreak or even, dare I say it - both... The only downside is that it's all so far out in La La Land, it'll have (as it stands) less than a 50% chance of verifying? Let's just hope it does!

Less, but then again, you would need to be quite brave to believe anything you see more than 144-168 hours out. That's an upgrade from last week though, when anything past 126 hours looked fantasy.

[Dennis]

A strong LOW