Model Output Discussion - 5th December - 11th December

[Slippery When White]

I've got some free time today so I'll do a pdf on where the low is going to form, indeed already started, and why, its probable track etc, sometime this afternoon or early evening.

I know for many on here you already appreciate what is happening and why but it may help new folk to get a better understanding of why our weather is described in climatology books as 'Disturbed Temperate' !

Excellent - I for one would definitely appreciate it. :-)

[snow1975]

I'm amazed everytime I veiw that sat site. Indeed, that upper jet cloud Is really motoring. Am I right in saying that feature that dropped down from the north toward N Scotland was a polar low?

I and I'm sure many others appreciate your PDF work... Can't wait to veiw it!

It could be a Polar Low....the strong PV, intense cold up north with a strong north-south temperature gradient leading to a strong baroclinic zone. It formed north of ther Polar front.....the 500hPa temperatures need to be below -42C....anyone confirm this?

[Costa Del Fal]

Models seem to be picking up a very favourable wind direction for the Cheshire Gap on Friday and Saturday which could deliver the first proper snow/snow showers of the winter to the Midlands, West especially. No guarantees with the Cheshire Gap though but with NNW'ly winds looking possible this is usually the best set up for the streamer. All depends on where the Low goes and how long it stays nearby but a good 24-36 hour window of showers from the Cheshire Gap look likely at this stage imo.

[weathe20]

Models seem to be picking up a very favourable wind direction for the Cheshire Gap on Friday and Saturday which could deliver the first proper snow/snow showers of the winter to the Midlands, West especially. No guarantees with the Cheshire Gap though but with NNW'ly winds looking possible this is usually the best set up for the streamer. All depends on where the Low goes and how long it stays nearby but a good 24-36 hour window of showers from the Cheshire Gap look likely at this stage imo.

Think you will be lucky with temps of 5, you would need plenty of elevation.

[johnholmes]

I'm amazed everytime I veiw that sat site. Indeed, that upper jet cloud Is really motoring. Am I right in saying that feature that dropped down from the north toward N Scotland was a polar low?

I and I'm sure many others appreciate your PDF work... Can't wait to veiw it!

I was a bit unsure about it being a polar low but it does look as if it was/is, and was correctly predicted as such by Dave Wheeler up on Fair Isle yesterday.

[syed2878]

Hi guys dnt post here much as i cant c the charths properly. I must say i do agree with the models even phillip edon forecasted this storm for the north later on this week and most of the time his forecasts r rite.

[Slowpoke]

Irish sea temps are well above average, so annoying!

[johnholmes]

the promised pdf about the expected storm

syed I hope it helps you and if you click on any chart it should enlarge for you?

Just tried it, you have to copy and paste into Paint it then enlarges

storm for thur etc-tue 6 dec 11.pdf

Edited December 6, 2011 by johnholmes

[Rocheydub]

Thanks JH, great analysis.

[shedhead]

The risk of a storm surge just increased quite significantly on the 12GFS.... IF that verifies, the north and east is going to take an

absolute battering from every weather type imaginable across Thurs and early Fri.

[doublebarrel]

Thanks John,As usual very informative excellent, thanks again

The risk of a storm surge just increased quite significantly on the 12GFS.... IF that verifies, the north and east is going to take an

absolute battering from every weather type imaginable across Thurs and early Fri.

Silly question i know but i`m near skegness thurs fri, whats it looking like for there thanks

[Liam J]

GFS 12z has shifted the storm slightly further southwards with more of N England in line for damaging winds on this run, Scotland still has the worse outcome with gusts to 100mph quite easily.

This could be a major event in many ways.

[Geordiesnow]

UKMO 12Z is slightly different regarding positioning of that potential major low pressure system with it taking a bit longer to head Eastwards which means the cold for Friday is downgraded quite a bit because the "mild" air within and around the low, I'm sure between 72-96 hours the cold air will flood down.

That low is a major concern especially for NE Scotland and NE England and if the air is cold enough then I would not like to imagine what conditions will be like on higher parts of Scotland but at least some exciting coming up.

[kold weather]

Very stormy looking week according to the 12z GFS, not so bad further south but the north is whacked by several powerful depressions. Also cold shots come in behind these lows so chance of wintry showers once again on high ground behind these low pressure cells.

Still not great really for coldies but at the very least its not a total SW-fest like it could have been.

[Bogman]

Well, it has started to rain down here, so that's slightly more interesting than it has been recently.

[IDO]

I would settle for the latest GFS run. Back to average zonal tonight I expect!

Edited December 6, 2011 by i'm dreaming of...

[Thundery wintry showers]

The GFS 12Z run could give serious structural damage for eastern parts of Scotland and possibly into NE England- the isobars are similarly tightly packed to the 3rd January 1976 storm, and a storm surge down the North Sea would be a real possibility. The UKMO has the isobars slightly further apart, implying a significant gale but probably not excessively damaging away from exposed areas. It's possible that GFS may be overblowing the low slightly here, but we have strong agreement on some pretty damaging winds, the only question being how damaging.

We do indeed see the return of cold zonality on the GFS run, albeit after T+144 so it is prone to changes- temperatures look similar to what we've been having so far this week, so some lying snow would be likely for Scotland and the high ground of northern England and the Midlands.

[shedhead]

UKMO 12Z is slightly different regarding positioning of that potential major low pressure system with it taking a bit longer to head Eastwards which means the cold for Friday is downgraded quite a bit because the "mild" air within and around the low, I'm sure between 72-96 hours the cold air will flood down. That low is a major concern especially for NE Scotland and NE England and if the air is cold enough then I would not like to imagine what conditions will be like on higher parts of Scotland but at least some exciting coming up.

I think any differences are minor GS. Both have the main low tracking east across the northern North Sea later Thursday into Friday, central pressure sub 960mb. GFS is slightly farther south, but it's marginal. The 12-18hrs it takes to cross the N Sea is going to build some very large waves, which will get forced south as the winds eventually swing around towards the north. IF these charts verify, this has got significant event written all over it imo.

Edited December 6, 2011 by shedhead

[A Winter's Tale]

chance of wintry showers once again on high ground behind these low pressure cells.

Still not great really for coldies but at the very least its not a total SW-fest like it could have been.

Not great for coldies? -10C uppers for much of Scotland sounds pretty cold for me and I would imagine if that's the case then precipiation will be wintry to all levels in the north.

[Thundery wintry showers]

I think, as per one of my posts yesterday, it really depends on where you live. For the most populated area of the UK (southern England) the progged setup is poor for snow lovers, as even the most potent bouts of cold zonality in the past have struggled to deliver any advance on wet snowfalls at low levels and accumulations mainly on hills. But for Scotland and Northern Ireland the outlook is pretty good for snow lovers (bar those concerned about major damage from Friday's windstorms).

[NorthernRab]

Not great for coldies? -10C uppers for much of Scotland sounds pretty cold for me and I would imagine if that's the case then precipiation will be wintry to all levels in the north.

Don't be stupid AWT, no one lives in Scotland.

In all seriousness, 90 or so mph winds mixed with heavy snow could be absolutely disastrous for the Highlands - add that to the possible storm surge on North Sea coasts - quite the weather we'll be having!

Edited December 6, 2011 by NorthernRab

[weathe20]

This is just another PM incursion this time with some strong winds. Again just normal UK winter fare, nothing to write home about. Think we know the winds will probably downgrade as the GFS loves a good storm only to kill it 24hrs in advance.

[Gavin Hannah]

I wuld say very significant hill snow on the mountains. Good cover 4 majority of scotland. Nt 2 much at sea level if any. Looking 4wd 2 this storm. Nt looking 4wd 2 replacing slates. This shuld boost the resorts nicely, esp east coast ones. Glencoe and Nevis r looking gd as it is.

[Aaron]

This is just another PM incursion this time with some strong winds. Again just normal UK winter fare, nothing to write home about. Think we know the winds will probably downgrade as the GFS loves a good storm only to kill it 24hrs in advance.

Nothing to write home about eh? Temperatures IMBY from GFS from tomorrow onwards:

4c,8c,2c,0c,2c,1c,3c,2c

Seems pretty chilly to me and the cold theme continues into FI.

[weathe20]

Nothing to write home about eh? Temperatures IMBY from GFS from tomorrow onwards:

4c,8c,2c,0c,2c,1c,3c,2c

Seems pretty chilly to me and the cold theme continues into FI.

Its winter..in the North and Scotland in winter this happens, cold some days with wintry ppn. That is normal UK conditions (ok there may be some strong wind too). This is the theme of the models, zonal with PM incursions in the north. As I said nothing to write home about, normal UK winter fare. Colder in the north milder in the south. We seem a little locked in this zonal theme, things would need a big turn around to get a county wide event with prelonged cold and snow....thats what you write home about...the unusual weather. Not the usual...as i descrided.

Edited December 6, 2011 by weathe20