Model output discussion pm 13/01/2016

[Geordiesnow]

At least there is some more signs again that the real mild air incursion is being slowed down which suggests the GFS runs yesterday was being over progressive. Still favour a much milder 2nd half of the week at this stage it has to be said but any changes in the short term which favours cold can of course delay any significantly mild air or even make it not occur at all. 

Always differences in the detail but the main pattern I see is for the outlook to turn less colder with the chance of some frontal snow(differences in the detail could make a huge differences on this) then the air slowly turns significantly milder for midweek onwards although admittedly the UKMO is once again not fully following that script.

[booferking]

ARPEGE run is great for us who love to prolong this cold spell..

[Cheshire Freeze]

1 minute ago, bluearmy said:

In Scotland -,yes

elsewhere chilly rain 

 

 

An interesting chart nonetheless though, wouldn't you agree Nick.....especially when you consider NWP has a torrid time modelling discreet, weak heights. 

[Nouska]

The models at 120 - serious resolution issues there.

GFS   UKMO     ARP 

[Ali1977]

How does the arpege do against ECM/UKMO and GFS?

[Gael_Force]

9 minutes ago, Ali1977 said:

How does the arpege do against ECM/UKMO and GFS?

On a par with ECM and UKMO supposedly but I'm not sure past performance is any guarantee in current situation. There's going to be some interesting verification graphs when this is done and dusted.

Edited January 15, 2016 by Gael_Force

[Glacier Point]

GFS starting to pick up the amplification coming out of the Western Pacific 23/24th January - where will the anomalous ridge manifest itself over NW Europe ? 12z going for Scandinavia. Not sure I'd agree with it there, and much will depend on modelling of the decline of the vortex over Greenland.

[Radiating Dendrite]

Do you think we will see a clean breakdown and return to mobility or a messy interim period before more amplification GP?

[karlos1983]

take a look at the GEFS purbs at around +72 as linked below. Majority show a much better undercut than the OP, very few are the same or worse.

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=72&code=16&mode=0&carte=1

[ALL ABOARD]

I count 16 gefs members at t66 that go with the low sliding !!!

[bluearmy]

9 minutes ago, CreweCold said:

An interesting chart nonetheless though, wouldn't you agree Nick.....especially when you consider NWP has a torrid time modelling discreet, weak heights. 

In respect of momentum not going ne, yes. however, day 6 charts not worth any detailed analysis at the moment CC.

[offerman]

 The front makes on Monday in from the west it will be rain because we are not behind the 850-5 line.  We are in the zero 850 green area which means rain . 

[Eskimo]

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

[Blake]

Clearly no point posting this really with the next 3 or 4 days unclear but this would be nice... -6 to -10s pushing back over the UK right at the end of the 12z with possible Thames streamer? Eastern areas and home counties would be most favoured.

 

[Yarmy]

Spread at T84 shows where all the uncertainty is (as if we didn't know):

 

 

 

 

 

 

[Glacier Point]

5 minutes ago, Radiating Dendrite said:

Do you think we will see a clean breakdown and return to mobility or a messy interim period before more amplification GP?

Messy - if nothing else on the basis of the messy and slightly incoherent composites for phase 6-7 of the GWO for January and how we relate those to the back end of January into February where these become more coherent.

[northwestsnow]

Just now, PerfectStorm said:

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

Lets hope its right, ukmo nowhere near as nice though i wouldnt have thought.

[Laurence Hill]

5 minutes ago, PerfectStorm said:

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

That's Tuesday isn't it?

[offerman]

6 minutes ago, PerfectStorm said:

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

 But the 850-5 line is over the continent so how can we get snow if we are in the green area ?

[bluearmy]

Just now, offerman said:

 But the 850-5 line is over the continent so how can we get snow if we are in the green area ?

far more to snow than uppers, especially with a continental flow

[Cheshire Freeze]

3 minutes ago, offerman said:

 But the 850-5 line is over the continent so how can we get snow if we are in the green area ?

Because you don't need uppers of -5 with an occluding front and a slight continental undercut. Anything under 0 at the 850 level should suffice- more especially if there's surface cold.

Some of the UK's best snow events have come with uppers above -5

Edited January 15, 2016 by CreweCold

[Blake]

1 minute ago, Sharpedge said:

That's Tuesday isn't it?

It's the total accumulations from start of snow on Monday until date and time on chart, covering about 24 hours.

[Chris1986]

What's that coming over the hill... Is it an easterly  pure FI but still

[Timmytour]

8 minutes ago, PerfectStorm said:

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

That's very much in line with what the GFS had for the same time......

Back on 7th Jan when it was about T300

 

[offerman]

7 minutes ago, PerfectStorm said:

The ARPEGE going for eye-watering amounts of snow (5-15cm) widely across the Wales, Midlands down to the southeast corner for Monday.

 But the 850-5 line is over the continent so how can we get snow if we are in the green area ?

 

 Hello  Blue , yes but if surface temperatures with the flow coming in from the south which is relatively mild  compared to  an easterly  component then I just don't see how we can get snow ?