Model Output Discussion - 18z 31/10/15 onwards

[Duane S.]

 

 

 

Now have a look at T240 ECM

 

 

 

 

 

BFTP

Indeed, which was of course followed by...

[Cheshire Freeze]

extended ecm maintains an upper ridge of sorts around greenland and a scandi trough. the atlantic running into the base of this troughing in our locale. expect a cooler set of london ens later.  interesting.

 

Sounds a snowy set up that- 1978ish?

[chionomaniac]

Beware the ECM... This is no strat split that we saw in 2009 or 2010. The GH op is trop led but is not supported by the lower strat EPS at 50hPa (so far). So any block is unlikely to be sustained for a long time. I think I am waiting a day or two on this to ensure that the ECm isn't over amplifying things...

 

....on the other hand, the forecast Siberian high anomaly is likely to lead to a possible MT based wave break that is likely to affect the upper strat and hopefully start to lead to a weakening from above following the exceptionally strong upper strat start. 

[Duane S.]

Beware the ECM... This is no strat split that we saw in 2009 or 2010. The GH op is trop led but is not supported by the lower strat EPS at 50hPa (so far). So any block is unlikely to be sustained for a long time. I think I am waiting a day or two on this to ensure that the ECm isn't over amplifying things...

 

....on the other hand, the forecast Siberian high anomaly is likely to lead to a possible MT based wave break that is likely to affect the upper strat and hopefully start to lead to a weakening from above following the exceptionally strong upper strat start.

Yep, my feeling too that it is (currently) difficult to see any sort of proper sustained cold spell emanating out of this for this reasons you state above. But with such a powerful strat vortex I would gladly take what the ECM is offering as an early winter bonus, even if it was short lived.

[Daniel*]

I have been going for a partially cold November for ages not one to brag I do not usually stick my neck out but I have felt something different was afoot this time with purple mass away from its usual home. It seems to be leading oddly to how I envisaged the month to go, I've remained quite sturdy on that and I await in interest whether this nagging feeling is printed into substance. It is annoying that the GFS isn't keen but I expect it to play catch up we need cross model agreement.

ECM +240

Simply bliss - 2010 undertones.

I advice a lot of caution here.

Edited November 13, 2015 by Daniel*

[Ali1977]

If GFS doesn't follow ECM perspective with what's happening in Paris needs to be shown. Awful...

Off topic sorry, back to GFS

Edited November 13, 2015 by Ali1977

[bluearmy]

Beware the ECM... This is no strat split that we saw in 2009 or 2010. The GH op is trop led but is not supported by the lower strat EPS at 50hPa (so far). So any block is unlikely to be sustained for a long time. I think I am waiting a day or two on this to ensure that the ECm isn't over amplifying things...

 

....on the other hand, the forecast Siberian high anomaly is likely to lead to a possible MT based wave break that is likely to affect the upper strat and hopefully start to lead to a weakening from above following the exceptionally strong upper strat start.

don't see any harm in posting some ECM strat charts courtesy of weatherbell as they will be freely available on the berlin site in the morning

At 10hpa, 30hpa and 50 hpa day 9

. .

Ed, that looks like a ridge of sorts to our west at 50hpa and the Scandi trough is certainly well supported high in the strat.

[SMU]

Indeed good ^^^^

Plus GFS through 96 much slower & advection is more pronounced & vertical -

S

[bobbydog]

Beware the ECM... This is no strat split that we saw in 2009 or 2010. The GH op is trop led but is not supported by the lower strat EPS at 50hPa (so far). So any block is unlikely to be sustained for a long time. I think I am waiting a day or two on this to ensure that the ECm isn't over amplifying things...

....on the other hand, the forecast Siberian high anomaly is likely to lead to a possible MT based wave break that is likely to affect the upper strat and hopefully start to lead to a weakening from above following the exceptionally strong upper strat start.

shush ed, next you'll be saying santa doesn't exist!

you never know, this could be a new variation on the strat/trop relationship.

Edited November 13, 2015 by bobbydog

[chionomaniac]

don't see any harm in posting some ECM strat charts courtesy of weatherbell as they will be freely available on the berlin site in the morning

At 10hpa, 30hpa and 50 hpa day 9

image.jpg. image.jpg. image.jpg

Ed, that looks like a ridge of sorts to our west at 50hpa and the Scandi trough is certainly well supported high in the strat.

Yep, just looked at them so agree to an extent - but the ensembles are understandibly more muted - so some strat support for the op, though the angle is not as favourable as though the original 'strike' had come through Greenland rather than Canada, so the wariness remains. 

Edited November 13, 2015 by chionomaniac

[Cheshire Freeze]

Indeed good ^^^^

Plus GFS through 96 much slower & advection is more pronounced & vertical -

S

 

Yes slightly better upstream but I'm doubtful whether it makes it on this run. Touch and go.

[bluearmy]

Yep, just looked at them so agree to an extent - but the ensembles are understandibly more muted - so some strat support for the op, though the angle is not as favourable as though the original 'strike' had come through Greenland rather than Canada, so the wariness remains.

I don't know about that ed - a decent angle to complete the ridge across to Siberia and cut off a chunk of vortex beneath ......... zzzzzzzzzzzz

I think I was dreaming !

[chionomaniac]

I don't know about that ed - a decent angle to complete the ridge across to Siberia and cut off a chunk of vortex beneath ......... zzzzzzzzzzzz

I think I was dreaming !

These type of lower strat splits are the most difficult to predict, but also can be the most rewarding. In 2009 and 2010 I remember significant strat lower wave splits on both the GFS and ECM prior to the cold spell - though GFS 18Z trending in the right direction...

[chionomaniac]

shush ed, next you'll be saying santa doesn't exist!

you never know, this could be a new variation on the strat/trop relationship.

It's not new, but it is the nirvana wave break and can occur prior to the upper strat vortex intensification reaching the trop. Tony and I have been waiting to see of this would occur, as there was a small chance this November and because of this chance had not released an early winter forecast preliminary. I had pretty much ruled it out last weekend though......still........

[Cheshire Freeze]

It's not new, but it is the nirvana wave break and can occur prior to the upper strat vortex intensification reaching the trop. Tony and I have been waiting to see of this would occur, as there was a small chance this November and because of this chance had not released an early winter forecast preliminary. I had pretty much ruled it out last weekend though......still........

 

So what sort of implications does this have going forward then? I'm guessing there would be ramifications for December?

[chionomaniac]

So what sort of implications does this have going forward then? I'm guessing there would be ramifications for December?

Well that would depend on any disruption on the upper strat from the Siberian high - and there are signs that that could occur as well.

[East_England_Stormchaser91]

Much better amplification on the pub run

And wow, before the cold, possible North Sea storm surge. <970mb slap bang in the middle of the North Sea heading down SE..

[bobbydog]

It's not new, but it is the nirvana wave break and can occur prior to the upper strat vortex intensification reaching the trop. Tony and I have been waiting to see of this would occur, as there was a small chance this November and because of this chance had not released an early winter forecast preliminary. I had pretty much ruled it out last weekend though......still........

i have been wondering in recent days, how we could have a strat seemingly wound up so tightly, yet the troposphere is so disjointed from that. with a 'dartboard' strat, how can the trop not be showing the classic 'standard' winter pattern? conversely, how can the strat be so strong with a 'battered' troposphere? going back to your analogy of 'two dancers', the forcings of el nino and the atlantic cold pool will inevitably have to filter up to and unbalance the stratosphere. (tripping up the other dancing partner). how this evolves is yet to be seen but maybe we are seeing the beginnings now. all that bottled up cold will have to go somewhere.

[Frosty.]

The Gfs 18z shows a wintry spell by the end of next week with frosts, ice, sleet and snow, much better than the gfs 12z with more cold weather to follow

Edited November 13, 2015 by Frosty.

[radiohead]

18Z GFS going for a Scandi high?

[ItNeverSnowsInWindsor]

Pleased with the output today with the various models offering different tones to the cool / cold outlook.At least the door is shut to the tM airmass taking dominance.

 

The jma seem keen on producing a Greenland High of magnitude as early as 96hrs which has some backing from ECM later at168T.... :cold:

Edited November 13, 2015 by prolongedSnowLover

[chionomaniac]

70hPa  18Z GFS strat chart - no split - just the distorted vortex - so caution should remain

 

 

Awaiting 1hPA temp chart at end of run

[East_England_Stormchaser91]

Well I never. The 18z has only gone for a classic 'Steve Murr sausage!'

What a monster it is too! Stretching from Siberia all the way out into the Atlantic with us on the southern periphery!! Exciting model watching at it's best right now.

[chionomaniac]

70hPa  18Z GFS strat chart - no split - just the distorted vortex - so caution should remain

 

NH_HGT_70mb_216.gif

 

Awaiting 1hPA temp chart at end of run

And here is the 1hPA temp chart

 

[Cheshire Freeze]

70hPa  18Z GFS strat chart - no split - just the distorted vortex - so caution should remain

 

NH_HGT_70mb_216.gif

 

Awaiting 1hPA temp chart at end of run

 

I'm not impressed by the GFS output at all. Yes there were some improvements on the 18z but ultimately it's not enough. Still the 0z is to come before the ECM updates but I'm firmly in your cautious camp for the time being.