Model Output Discussion 13/11/13 >

[UV-RAY]

Well I might pick up a snow shower or two tuesday afternoon here before the wind swings westerly prior to the incoming low from the north. Probably the only real chance at low levels unless the cold behind Wednesdays low upgrades over the coming runs.

One thing I do wonder about is whether the models will upgrade that low, the GFS has upped the ante over the runs today, lets see whether it continues.

Wednesday looks like a pretty awful day

Heavy rain and strong to potentially gale force North/North westerly winds.

Indeed it does look awful, not what we envisaged a few days ago. At least the pattern looks set for plenty of sunshine and frosty weather from the latter part of the week onwards.

[Ǝssex Ǝasterly]

Some are saying snow to lower levels only up in the northern half of the country, I can see they have -8 uppers, where I have -6, Metcheck shows snow for my area overnight, is it more or less a case of waiting for the precipitation and seeing what falls out of the sky?

 

Max temps here for Tues / Weds are 3.5c, also I can't see where much of this precipitation is coming from, the GFS has a few gaps in it? 

 

Waiting for the 12z run to finish updating right now!

Edited November 17, 2013 by Essex Easterly.

[Geordiesnow]

Well I might pick up a snow shower or two tuesday afternoon here before the wind swings westerly prior to the incoming low from the north. Probably the only real chance at low levels unless the cold behind Wednesdays low upgrades over the coming runs.

One thing I do wonder about is whether the models will upgrade that low, the GFS has upped the ante over the runs today, lets see whether it continues.

Wednesday looks like a pretty awful day

Heavy rain and strong to potentially gale force North/North westerly winds.

 

Could be touching severe gale on some Northern and Western coasts so instead of all this talk of snow and what not, it seems the major weather story next week could be the chilly but quite windy weather. 

 

The detail is still not quite clear though, what the strong winds may do is to help to bring another push of cold air down from the North but the main window of wintry weather seems to be Monday night into Tuesday with snow showers getting down to lower levels during Monday Night in Northern parts of Scotland, maybe even for a time into Eastern Scotland, would not be surprised if there is reports of snowfall in Aberdeenshire but I think any snowfall may struggle to accumulate at lower levels. 

[Matty M]

Yep main trend in the shortish term is the upgrading of intensity of the low around 72hrs, this itself will aid increased cold air advection to our north.

Edited November 17, 2013 by Matty M

[AWD]

Just a few coastal flurries on the NAE 12z 48hr chart;

Should have looked at Monday night too! Oops! Northern Ireland could be a sweet spot Monday night;

Along with northern Scotland as you'd expect;

Nothing too substantial though anywhere! England & Wales mostly dry?

Edited November 17, 2013 by AWD

[Summer Sun]

GFS 12z continuing to ease the 850's by Thursday

 

 

So precipitation may start wintry but it would turn to rain before clearing away

 

 

Pressure starting to rise in the north

 

Edited November 17, 2013 by Summer Sun

[Snowman.]

Some are saying snow to lower levels only up in the northern half of the country, I can see they have -8 uppers, where I have -6, Metcheck shows snow for my area overnight, is it more or less a case of waiting for the precipitation and seeing what falls out of the sky?

 

Max temps here for Tues / Weds are 3.5c, also I can't see where much of this precipitation is coming from, the GFS has a few gaps in it? 

 

Waiting for the 18z run to finish updating right now!

Metcheck uses raw GFS output.

 

Stick with Met Office.

[Geordiesnow]

Indeed it does look awful, not what we envisaged a few days ago. At least the pattern looks set for plenty of sunshine and frosty weather from the latter part of the week onwards.

 

That is certainly the case, what looked like a cold but bright period does now to be changing to a more dull, cold horrible and for some quite wet outlook. The true Northerly airflow occurs on Monday night into Tuesday and I suspect once the air gets mixed out, it will turn duller and wetter especially in eastern areas. 

[Mucka]

Thanks Steve, if my posts always illicit such a detailed and eloquent response I will be asking you more questions in the future. 

 

I don't think you took my post the wrong way but just to clarify I wasn't suggesting you were hopecasting, I was  more interested in your reasoning for going with the more amplified charts as being closer to what will transpire. I am a long time reader and poster on a few forums so I am aware of your history and your contempt for GFS because of its more zonal bias. I wouldn't go as far as you in dismissing it but no doubt you are correct in what you are saying in my mind.

I still find the GFS useful with its 6hr frame advances and it is good at spotting trends in FI IMO if you know what to look for. I posted on Nov 3rd it was hinting at more blocking as we headed into the second half of November. It may not of happened but the signal was there within its ensembles.

 

What I really found interesting in your reply was that you felt the Euros still had a slight bias for sending too much energy over a block. (is that fair?)

look at the second point though- if everything is now reversed then the Euros are not amplified enough & will always play catch up to the 'new Post Mod ern winter'...

 

Can that be shown statistically or is that just a gut feeling you have influenced by the atmospheric changes in recent years that you pointed out?

I'm not saying you are wrong but my view is that when dealing with split energy it is a toss up as to whether they send too much NE or SE although I guess it is reasonable to assume there is a slight bias that tips them one way or the other if they are not proven correct.

 

It is a very interesting subject and a worthwhile project to find faults(bias) within the models but expect it would take many years of data. Obviously the programmers of the various models already have such data and improve upon them using this data from time to time (that and the obvious addition of new data gathering and measurement techniques along with any new knowledge of how our atmosphere works) 

I can't see them releasing it here though. 

 

It looks on knife edge to me and even taking account of all you have said I am not seeing a strong signal for HLB at the moment but nor am I seeing the Atlantic making any inroads and a "collapse of the pattern" as has been suggested. Yes I have got splinters in my A***!

Anyway, I hope you are proven right again and we get some HLB in place for December and I will be among the first to give you credit (I know you are not here for popularity or point scoring either)

 

Thanks again for taking the time and energy to explain your thoughts, it is very much appreciated.

Edited November 17, 2013 by Mucka

[Snowman.]

The more energy going into Europe the better.

 

 

 

Stops the High from sinking South and keeps it north allowing pressure systems to slip under it much more easily.

[Methuselah]

Well, if people didn't base their expectations on the most outlandishly extreme model-runs, all this disappointment wouldn't occur? 

[Summer Sun]

Not far off the 06z so far pressure slowly rising by Friday inline with the thoughts of the met office quietening things down though remaining chilly

 

Edited November 17, 2013 by Summer Sun

[shaky]

Much better 12z early on.heights rising to our north and more energy into europe.cant wait to see the ukmo

[Snowman.]

FI is around 96 mark.

 

Here is the differences with the GFS and ECM.

 

 

 

ECM

 

Pretty big considering the range.

[That ECM]

FI is around 96 mark.

 

Here is the differences with the GFS and ECM.

 

 

 

ECM

 

Pretty big considering the range.

Can't post charts but view NH charts.

[Snowy L]

Still pretty similar to the 06z, more elongated low though which is good to see.

[Captain Shortwave]

Not there yet but it is a movement towards the ECM on the 12z GFS

Low over Northern Scandi should drop south east a little quicker and further west with better WAA to the north.

Edited November 17, 2013 by Captain shortwave

[Jonan92]

It seems that in this run the energy is going over the top, while in the previous run the low was pushing to the east. We may see a retrogression of the high once the low reaches the top

[The Northern Ramper]

That low is slightly stronger and a little further west on the 12Z GFS.

 

And doesn't the 12z GFS have an Eastward bias?

[The Northern Ramper]

FI is around 96 mark.

 

Here is the differences with the GFS and ECM.

 

 

 

ECM

 

Pretty big considering the range.

The GFS has 12 hours more info though, probably best to compare it to the 12z ECM before stating where FI starts.

[Snowman.]

Aye Aye.

 

Heights making it into southern greenland all you need is the low to drop down.

[Panayiotis]

Looking better at 174hrs! Little surface high pressure on southern tip of Greenland should keep that low to the SW of it, more or less stationary allowing WAA northwards!

Edited November 17, 2013 by Panayiotis

[Snowman.]

The GFS has 12 hours more info though, probably best to compare it to the 12z ECM before stating where FI starts.

Here is the 0z.

 

 

 

Then the 12z

 

Edited November 17, 2013 by SN0WM4N

[nick sussex]

Just to add something to Steve M's post regarding the UKMO. Whilst this model only goes out to public view upto 144hrs and in house 168hrs so it doesn't have the chance to pick up something new post that time for us to see. So it might not be a future trend setter or indicate a pattern change but certainly its like the deciding judge in the court of Appeal! If you're dealing with European blocking patterns, such as Scandi highs its a no go without this model on board, it's harpooned many an easterly in my time by resolutely refusing to budge.

 

The UKMO upto T72hrs and you can already see a difference with its transport of lower heights over Greenland compared to the GFS just run the 60 to 72hrs on both and see how the GFS takes this east and the UKMO ne.

 

We can see how this initial change magnifies further at 96 and 120hrs.

Edited November 17, 2013 by nick sussex

[Snowman.]

GFS being consistent.