Model Output Discussion 01/09/17

[comet]

12 minutes ago, bluearmy said:

Too much misery on here - I just checked my calendar ..........

too much stock being placed in long range output, extended ens data and volatile op runs - plus assumptions from strat data.

Couldn't agree more.

[booferking]

It couldn't could it

Edited November 17, 2017 by booferking

[frosty ground]

6 hours ago, frosty ground said:

The GFS 06Z Ensembles show a lot more scatter for next week and good agreement for it to be cool in the final third.
06z0z

Looking at the 12z the shift away from south westerlys is gathering pace ...

 

[Ali1977]

ECM at +96 is so close to being good, especially using the NH view !!

Edited November 17, 2017 by Ali1977

[booferking]

That is extremely close to being very good..

[chrisbell-nottheweatherman]

6 minutes ago, frosty ground said:

Looking at the 12z the shift away from south westerlys is gathering pace ...

 

This is much more apparent than on the 06z, IMO.

[SMU]

Scotland clinging onto the cold air & Easterly flow with a band of rain spreading North turning to snow along the borders !

[nick sussex]

More drama!

The ECM now has a possible snow event on the northern flank of the low at T120hrs! The UKMO has just rain and a rapidly deepening low!

The differences because of phase point and timing of those deeper blues to the ne with the low to the sw, you'll note the slightly different angle of the isobars bringing that down between the outputs this is now making a huge difference. Dear me its painful to watch!

[Summer Sun]

Even at t120 ECM and UKMO have differences in the 850's over the UK

[SMU]

Just to add to the drama ECM sliding the low out into the North sea leaving parts of scotland with a pasting-

good signals for the hills & ski resorts !

[swfc]

1 hour ago, swfc said:

Bank that 240hr chart!!.things heading south from t-90 hrs on 12z.

And on ecm !!

[The PIT]

Models 2 and 3 Versus Model no.1 which shows us why this evening forecast was rather cautious.

[nick sussex]

The stakes just got higher for members in the far north. Which means if you like snow your nerves will be shredded!

Its a long time since I've seen now what seem tiny differences on a global scale making such a big impact with such a small margin between the UKMO washout and some early snow fun for some lucky members on the ECM.

Crucially on the ECM you'll see the low flatter and shallower at T120hrs with more energy managing get east before those deep blues to the ne make contact.

As soon as First Contact is made! Yes I slipped in my film analogy at last! then you'll get a deepening low trying to travel more ne which means its key to get the pattern as far east and south before that happens.

Unfortunately its a stretch to get some UK wide snow from this set up, we'd need massive changes which at this timeframe would be difficult to imagine but there is a chance some members from the far north could see some snow.

However we have disagreements between the outputs which dents confidence in the ECM solution so we're going to have to wait till tomorrow morning to see whether its solution is a real possibility.

Edited November 17, 2017 by nick sussex

[stodge]

Evening all

More fascinating twists and turns tonight. The 12Z GFS OP is very stormy and unsettled and much less mild than a couple of earlier outings. The Control also sends the jet well to the south keeping the British Isles stormy, unsettled and prone to incursions of PM air.

The key seems to be the exact location of the core of LP - the OP and a number of the members take the LP over or just to the east while others hold the LP centre further west bringing in a flow of very mild southwesterlies, 

The ECM and GEM look very close tonight - both keep the jet a tad further north with stronger heights to our south and active LP crossing the north of the British Isles.

Overall, it looks like a stormy final third to November with much more rain and wind than we've seen of late - severe gales or even storm force winds likely for coastal areas and to altitude.  

[Summer Sun]

Some significant temperature differences next week from GFS northern Scotland gets into winter whilst the rest of the UK sees spring like temps

[LRD]

As with GFS, the ECM seems to be pushing things a bit further south (ECM 12z doesn't do this as much as GFS 12z does though). Not winter yet by any means but it's still looking blocky on the ECM 216 with a negatively-tilted low south of Greenland that has our name on it.

http://www.wetterzentrale.de/de/topkarten.php?map=1&model=ecm&var=1&run=12&time=216&lid=OP&h=0&mv=0&tr=24#mapref

This is something I will be watching out for. Will the models continue to trend things further south over the weekend's runs?

Edited November 17, 2017 by LRD

[LRD]

3 minutes ago, Summer Sun said:

Some significant temperature differences next week from GFS northern Scotland gets into winter whilst the rest of the UK sees spring like temps

IF the GFS is right those warm temperatures would not last for very long and wouldn't return very quickly either

[nick sussex]

Good and bad from the ECM tonight for coldies.

Better early not as good post T168hrs than the 00hrs run. Theres no separation upstream which means we can't get high pressure to the south to edge nw and allow a dip se near the UK in the jet.

At this point though I think we should be looking in the nearer timeframe as that's where theres some interest. Overall it does look unsettled with lots of wind and rain, a chance of snow for the north.

The boundary between cold and milder is never far away from the UK so southwards corrections in the output could make a big difference.

[chris55]

With the broad scale pattern determined to a point for the medium range, i.e. Negative AO with a west based NAO I have a feeling our patch could well get in on the action at some stage going forward. 

Grower not a shower comes to mind with the NWP at this point. 

We shall see, but tonight's ECM does sink the cold further south so you never know. 

Certainly an early start to the silly season  

[booferking]

CFS is similar to ECM tonight still a day in this yet to resolve the outcome,  could still go further south yet.

[I remember Atlantic 252]

20 minutes ago, Summer Sun said:

Some significant temperature differences next week from GFS northern Scotland gets into winter whilst the rest of the UK sees spring like temps

I would prefer setup north as here on SS post, looks reasonable for the south, dry/warm, if whole setup moves south, could be looking at a very wet setup for the South, hope to see northward trend on ECM if we want a pleasant south

[Day 10]

Dear me ECM, just when you think the first chase is curtains it dangles the carrot. 18z it is then! 122 days til Spring and Winter hasn't even begun yet!

[East_England_Stormchaser91]

Will be very interesting to see how the models deal with this current projected northern blocking set to happen over the coming days. The line is fishing wire thin as to whether we see mild SWerlies or that low managing to slide away and bring the cold down over the country.. 

[ItNeverSnowsInWindsor]

Not liking the positively tilted jet helped by the dreaded Bartlett! ?

[knocker]

Looks like being very unsettled next week so a brief look at tonight's ecm.

After a quiet Sunday Monday 00 sees a low spawned from the main tough in the western Atlantic south of Ireland with the associated front aligned roughly NW/SE west of Scotland. It duly tracks across Scotland in the next 24 hours and it maywell dump some snow on the high ground although it may be tad too far north.

Simultaneously another disturbance has broken away from the main trough which is now further south and has tracked north east with the front across N.Ireland. Wales and SE England by 12 Tuesday accompanied by rain. And this is where it gets complicated, Over the next 12 hours the front moves slowly north (And it could well produce snow on the high ground along it's leading edge) whilst at the same time another trough has slipped south from NE Greenland to be between Iceland Scotland bringing with it much colder air. The sharp delineation between this and the warmer air runs almost due west from the borders by Weds 00.

From this point the depression and the front track north east, again snow on the higher ground, into the North Sea by 12 Thursday as the colder air to the west continues to sink south and although the UK is in the strong circulation of the  aforementioned low the whole of the eastern Atlantic and to the south west id under a complex upper trough.

Edited November 17, 2017 by knocker