Model Output Discussions 12z 01/09/2016

[Ravelin]

3 minutes ago, feb1991blizzard said:

I would take the 12z and thought so from quite early on in this 18z, 12z is miles better.

 

The upper ridge wasn't sharp enough on this run.

I'd agree. We do end up with this...

Which looks good on the face of it, but the uppers aren't anything special...

[feb1991blizzard]

Just now, Kieran said:

I agree but both runs give us a good shot of cold with similar uppers. The 18z prolongs the cold for abit longer though. However both runs give us a second shot of cold so both runs are great IMO.

Yes one thing I have noticed (only really applies to GFS because others (ops) don't go far out enough) is that no matter how much it looks like a run is going to fail in low res and default to zonal, something seems to override it and another bout of blocking takes place, this model watching really does have a touch of the 09/10 and Dec 10's about it, cannot recall another time when every GFS op seems to have a default of blocked in low res as opposed to its usual zonal.

[feb1991blizzard]

If the ECM ens have removed the trough to our east, the GEFS seem to be intensifying it, some belters up to 240.

[bluearmy]

1 hour ago, feb1991blizzard said:

If the ECM ens have removed the trough to our east, the GEFS seem to be intensifying it, some belters up to 240.

Not sure where that's come from - extended eps retain upper ridge/trough/ridge/trough from the eastern Alaska around to Eastern Europe. What does relax is the low sceuro anomoly in conjunction with the upper trough which seems consistent with the recent ec 46 which showed a pulling back of this amololy around mid month for just over a week before it returned for the last week Nov. 

It is true that the mean upper ridge trough Atlantic/e Europe is not as marked as Alaska/eastern USA (which is also consistent with previous output) and I continue to wonder what happens with the consequential jet streak appearing in two weeks time off the eastern seaboard as crucial to the last half of the month downstream. 

 

[bluearmy]

Incidentally, not sure what the verification stats are like but the FIM model seems to be doing a reasonable job in the 6/10 day area when anecdotally compared to ecm/gfs 

the 12z run is a broad reflection of the ecm parallel in its latter stages (which isn't far from the ecm op) 

[feb1991blizzard]

6 hours ago, knocker said:

Well at least the EPS is getting rid of that pesky trough to the east thus a much more sensible flow from a westerly quadrant with perhaps a move towards more average temps.

This post suggests the removal of the trough by ECM ens BA.

[knocker]

35 minutes ago, feb1991blizzard said:

This post suggests the removal of the trough by ECM ens BA.

Just to clarify that. It wasn't in the 6-10 day period but towards the end of the 10-15.

[feb1991blizzard]

1 minute ago, knocker said:

Just to clarify that. It wasn't in the 6-10 day period but towards the end of the 10-15.

OK, I cant comment synoptically myself as only have access in graph form but the London ext ones do slightly warm up right at the end

[bluearmy]

I was speaking about the 10/15 day eps

Low sceuro anomaly departs but upper eastern Euro trough (shallow) remains 

Suspect that means for us the mid Atlantic high will push in across us though a lack of anomoly usually means pattern up for grabs 

Edited October 30, 2016 by bluearmy

[feb1991blizzard]

3 minutes ago, bluearmy said:

I was speaking about the 10/15 day eps

Low sceuro anomaly departs but upper eastern Euro trough (shallow) remains 

Suspect that means for us the mid Atlantic high will push in across us though a lack of anomoly usually means pattern up for grabs 

Yes that's what's happened on some op runs late on lately.

[knocker]

9 minutes ago, bluearmy said:

I was speaking about the 10/15 day eps

Low sceuro anomaly departs but upper eastern Euro trough (shallow) remains 

 

I don't have a problem with that as it was the former to which I referred as this is the pesky one. I know the bigger picture before we start on another trail. and just to add nowhere in my earlier somewhat cryptic post did I mention mild. The indication is for them to rise to just about average as you are no doubt aware. It's quite a strong indication of positive Atlantic heights given the range.

One lesson to take from this whole sorry saga Knocker. Refrain from cryptic one  liners.

Edited October 30, 2016 by knocker

[Frosty.]

I'm very happy with the Gfs 00z as it shows our weather mostly coming from the nw / n / ne during the next few weeks with reloading cold shots of varying potency but we would all have widespread frosts at times and some of us, especially in the north and on hills would get some lovely snow!

[knocker]

Today

Not dissimilar t yesterday with the UK still under the influence of the dirty high so cloudy with sunny intervals although northern Scotland may see some showers.

And so on the GFS this morning.

The first upper low tracking in from the west tracks SE  into the Baltic States by early Wednesday which initiates the pattern change over the UK by introducing a cool northerly flow.

This is quickly followed by HP tending to nudge in for a couple of days and  backing the flow westerly and perhaps lifting the temps to around average. But this also is very short lived as the next low arrives north west of Scotland by 00z Saturday and phases in with the trough to the east. To complete the picture we have ridging into Geenland and the cut off upper low NW of Africa.

So we are now poised for the transformation. Amplification takes place and the trough intensifies and is centred over Denmark by 0600z Monday so the UK back into a very cold, unstable, northerly with temps significantly under average. The transition to this position portends a quite grotty weekend for most although not particularly cold at this stage.

From this position the trough slips south and slowly reorientates keeping the cold airflow over the UK for a while but towards the end of the week the wind has backed and temps risen once again. But now the next deepening upper low has arrived NW of Scotland, originating from the eastern seaboard but this will keep for another day.

 

Edited October 30, 2016 by knocker

[bluearmy]

Within that broad evolution knocker, there remains a significant chance of a slider system against colder air in situ (albeit with an apparent westerly flow ahead of the fronts which would veer se) 

at this time of year, that would probably only bring proper snowfall to hills and mainly in the west as the North Sea would likely raise low level air dp's too high away from the really high ground. 

[northwestsnow]

3 minutes ago, bluearmy said:

Within that broad evolution knocker, there remains a significant chance of a slider system against colder air in situ (albeit with an apparent westerly flow ahead of the fronts which would veer se) 

at this time of year, that would probably only bring proper snowfall to hills and mainly in the west as the North Sea would likely raise low level air dp's too high away from the really high ground. 

Was just going to post something similar - if the GFS0Z is anywhere near the mark i feel elevated placed in NW Britian could see their first snowfall before we hit mid November, a rough stab at 300m+, i know its early days but the days themselves get shorter pretty sharpish between now and mid December,either way its a very different situation form last year,i think the Atlantic was just getting into gear round about this time..

[knocker]

14 minutes ago, bluearmy said:

Within that broad evolution knocker, there remains a significant chance of a slider system against colder air in situ (albeit with an apparent westerly flow ahead of the fronts which would veer se) 

at this time of year, that would probably only bring proper snowfall to hills and mainly in the west as the North Sea would likely raise low level air dp's too high away from the really high ground. 

But the output isn't indicating this although your post is not quite clear on the timing  so some clarification on this and the meteorological specifics would be appreciated. Personally I think the significant event of the run is the track and intensification of the upper low over the weekend but that's just my opinion of course.

Edited October 30, 2016 by knocker

[northwestsnow]

Some very dense cold spilling into Scandy from the Arctic on ecm 168-

http://old.wetterzentrale.de/pics/Recm1682.html

-5 upprs into Northern Scotland, showers turning snowy at altitude?

Edited October 30, 2016 by northwestsnow

[Matthew.]

Yes agree with above, ECM 0z has COLD cold air lurking to the north next Sunday. A very different 1st week of November compared to the anomaly.

[northwestsnow]

ECM looks pretty cold at 192 as we drage the cold scandanavian air across the North- sub zero nights and single figure max across northern england and Scotland by this stage.

On the downside the jet looks to be riding over the high although the pressure low across Southern Europe we may see a UK high?

Turns milder at the end but i'm not entirely sure that would be long lasting - signs of a rinse and repeat?

Edited October 30, 2016 by northwestsnow

[knocker]

Just in case it gets forgotten the ecm does have the upper low slipping SE over the UK on Friday  Which portends some pretty grotty weather Friday and Saturday as the surface low and fronts traverse the country. Oh and there is some quite cold air in the south west quadrant of the depression.

 

Edited October 30, 2016 by knocker

[northwestsnow]

Yes was going to comment on the Bonfire weekend, looks pretty poor now acc to the ECM, cold yes, cold rain  though, i was hoping for a cold dry weekend, which is what it will likely become soonafter ...

[Frosty.]

The Ecm 00z after a mild start turns cooler from the NW and then increasingly cold from the north next weekend  and into early week 2 as we draw arctic air south. As well as rain and showers, there would also be wintry ppn, even some snow on northern hills along with occasionally frosty nights with icy patches and even T+240 suggests our next cold shot would soon follow with the jet aligned nw / se..I'm happy with the trend again from the gfs and ecm and this could evolve even more favourably on subsequent runs!

Considering the meteorological winter is still 4 weeks away I would treat any cold weather in the meantime as a juicy bonus!

Edited October 30, 2016 by Frosty.

[Nick F]

The scenario of the low pressure system dropping SE across Nern Britain then on across N Germany & Denmark in tandem with height rises north to Iceland & Greenland next weekend seems to be common ground for a while now in the models. However, questions marks toward the end of the medium on range over how long the greeny ridge and resultant cold N to NEly flow developing end of next w/e will maintain.

A look at the northern hemisphere view from the operationals this morning has GFS maintaining the ridge to the  N and NW into the extended range but ECM breaks down the ridge as it has a lobe of the polar vortex over northern Canada drift E across Greenland toward the  end of the medium range, which causes low(s) to develop off Sern tip of Greenland then slide SE toward northern Scotland.

More runs needed, wouldn't place my money on the 00z ECM operational just yet.

Edited October 30, 2016 by Nick F

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

all i  say  if f1  right  this  place  could  go in to melt down by nov 15

[knocker]

9 minutes ago, Nick F said:

The scenario of the low pressure system dropping SE across Nern Britain then on across N Germany & Denmark in tandem with height rises north to Iceland & Greenland next weekend seems to be common ground for a while now in the models. However, questions marks toward the end of the medium on range over how long the greeny ridge and resultant cold N to NEly flow developing end of next w/e will maintain.

A look at the northern hemisphere view from the operationals this morning has GFS maintaining the ridge to the  N and NW into the extended range but ECM breaks down the ridge as it has a lobe of the polar vortex over northern Canada drift E across Greenland toward the  end of the medium range, which causes low(s) to develop off Sern tip of Greenland then slide SE toward northern Scotland.

More runs needed, wouldn't place my money on the 00z ECM operational just yet.

Yes I would agree with that obviously but have taken 5/2 with Ladbrokes.