Model Output Discussion - cold spell to end Autumn

[nick sussex]

Still not convinced by the ECM.

This mornings run has less energy spilling east over Greenland than last night upto T168hrs and has the low track further south but then still conspires to push a lot of energy east after that.

You can indeed trace some of these differences back to the Pacific. The UKMO has the most amplified PNA ridge at T144hrs and although we don't have a full view of the UKMO that looks the best of the outputs at T168hrs as that amplification will hold the most energy back downstream.

The GFS although not quite as good as last night in terms of a snow event looks a reasonable middle ground solution between the ECM and UKMO.

If MOGREPS supports the UKMO over the east Pacific then I'd expect their Meto update to still look interesting.

 

 

[Dennis]

lets have some winter fun times - winterstart is different from last years ; also we can see the Polarvortex is not at the place for strong westerlies

[carinthian]

5 minutes ago, That ECM said:

It's difficult to ascertain where it would go from there as we don't get to see the nh profile but following gfs and continuation of the northerly theme is a distinct possibility wouldn't you say?

 

35 minutes ago, Steve Murr said:

UKMO day 7

pretty chipper Northerly!

Based on this chart , looks like the UKMO alignment is more like the GFS at the same time with undercut profile rather than toppler ECM. Will now be interested in watching UKMO fax charts and forecaster adjustments over this week end with the handling of the developing low and high pressure alignments . This will now give us some indication where we are heading. However, just watched a rather uninspiring BBC weather presentation that reports a mild start to the week across the British Isles, then a risk of heavy rain and strong winds for some and possible cold return from the north. Well that's another story. Great model watching continues for the start of winter. Looks rather benign over here compared to what you lot can expect later next week.

C

[pureasthedriven]

Still a ticking with my favourite model ???

Must say, that MetO overnighter looks out of kilter with their own model and even to an extent the somewhat underwhelming ECM 00z. 

[Dennis]

lets bring those E-ly 

[MKN]

Looking across this mornings output low lying areas are looking at a washout rather than a whiteout in terms of the low crossing the country followed by snow showers for ths usual suspects from a northerly. Past experiences also favour this outcome as to get the heavy snowfall people are looking for the timings the position of the low and the shape of the low all have to be perfect.

[pureasthedriven]

5 minutes ago, carinthian said:

 

Based on this chart , looks like the UKMO alignment is more like the GFS at the same time with undercut profile rather than toppler ECM. Will now be interested in watching UKMO fax charts and forecaster adjustments over this week end with the handling of the developing low and high pressure alignments . This will now give us some indication where we are heading. However, just watched a rather uninspiring BBC weather presentation that reports a mild start to the week across the British Isles, then a risk of heavy rain and strong winds for some and possible cold return from the north. Well that's another story. Great model watching continues for the start of winter. Looks rather benign over here compared to what you lot can expect later next week.

C

As for the Beeb, they never stick their neck out when there is even the remotest uncertainty. You can understand why but I find their post 48 hour forecasts are best left alone. But that’s for another thread. 

[SMU]

38 minutes ago, That ECM said:

It's difficult to ascertain where it would go from there as we don't get to see the nh profile but following gfs and continuation of the northerly theme is a distinct possibility wouldn't you say?

Yep agree with Carinth - although UKMO 144 I believe has the low to far North

I think based on History somewhere across the Midlands then out towards Benelux-

The ECM mean clustering has many more colder solutions that the op & control at day 10/11 for debilt..

[Daniel*]

26 minutes ago, MKN said:

Looking across this mornings output low lying areas are looking at a washout rather than a whiteout in terms of the low crossing the country followed by snow showers for ths usual suspects from a northerly. Past experiences also favour this outcome as to get the heavy snowfall people are looking for the timings the position of the low and the shape of the low all have to be perfect. 

That’s really not the case...no one should be expecting powder snow.

wet snow is typically the most disruptive kind it coats everything & it has the potential to fall across swathes of the country, probably following after a bit of a washout. With a low making inroads with a cold air mass also on the move S, there are a range of possibilities depending on your location.

Edited December 2, 2017 by Daniel*

[kold weather]

The ECM master run does have a backedge snow event, high ground for the west, low ground to the SE with 1-2cms accumulations.

ECM ensembles have a real mix with that event, some ensembles have a big snow event for the country, though I'd say most are close to the master run in terms of amounts, though locations vary.

Beyond that, ECM ensembles are still more cold than not but huge range of options!

 

 

[Weather-history]

1 hour ago, northwestsnow said:

TBF the EC mean at day 10 looks OK, scandy low sinking south into Europe,only issue is the azores high- hopefully the cold trough will drop anchor across southern France..

meanwhile events in the strat could begetting intersting-zonal winds forecast  to start dropping off again!!

late November-early December 2008esque

[bluearmy]

I see a lot of excitement on here without too much evidence. Anyway, I hope to see some upgrading of the output once it reaches T120/96 to justify it. 

The extnded eps drifting away a bit from the depth of the sceuro anomoly by the end of week two - looks like cool zonality although it seems the Canadian lobe spouting out every few days is responsible and it may well be quite different in a few days as the modelling gets a better handle on how upstream will develop. The meto currently seem to be ok on this with their outlook. 

[Frosty.]

I think excitement is justified with some of the output showing a very cold arctic flow towards the end of next week but there is of course caution as this is the uk and anything to do with cold isn't straightforward but I'm very happy with the potential again this morning.

[Chesil View]

Its certainly a delicate balancing act as to who gets wet and who gets white later next week but at six days out no doubt alit more adjustments to come.

[Methuselah]

29 minutes ago, kold weather said:

The ECM master run does have a backedge snow event, high ground for the west, low ground to the SE with 1-2cms accumulations.

ECM ensembles have a real mix with that event, some ensembles have a big snow event for the country, though I'd say most are close to the master run in terms of amounts, though locations vary.

Beyond that, ECM ensembles are still more cold than not but huge range of options!

 

 

Hi kold...haven't heard anything from you in, like, years! I'm guessing that the outlook holds promise?

[MattStoke]

6z has better height rises towards Greenland but also has the low deeper and further north. The cold uppers slower to push across the UK as a result.

[That ECM]

A small improvement again. 

[Ice Day]

Wow!  Day 6 on the 6z is looking superb......

 

A secondary push of heights up to Greenland. Excellent stuff.

Edited December 2, 2017 by Ice Day

[Spah1]

18z? 

[nick sussex]

Good stuff from the GFS 06hrs run so far, more amplified PNA ridge at T144hrs like the UKMO.

This will help stop too much energy from spilling east.

Really becoming a tremendous run now trough disruption to the west of Greenland.

Edited December 2, 2017 by nick sussex

[Ice Day]

That low is just sitting there in the North Sea.  Scottish mountains will be significant taller by the end of this!

Edited December 2, 2017 by Ice Day

[SMU]

Extreme amplification in the atlantic sees the energy aimed at spain at 168!

Edited December 2, 2017 by Steve Murr

[Ice Day]

5 minutes ago, Spah1 said:

18z? 

Ooops.  Corrected now.  I really shouldn't try posting whilst making a cup of tea!

[Dennis]

ARCTIC air

[Frosty.]

10 minutes ago, Ice Day said:

Wow!  Day 6 on the 6z is looking superb......

 

A secondary push of heights up to Greenland. Excellent stuff.

The 6z is giving coldies more reasons to be excited