The hunt for cold - Model discussion (late November)

[jules216]

If we isolate MJO and pretend we trust the GEFS progression of it. Then a period of +NAO would fit OK with last week before and around Christmas.

We then hopefully see a coherent passage through phases 6 and 7 between Christmas and New Year which then correlate with -NAO.

How nice if the advection of blocking happens in the same time as SSW.

[Skullzrulerz]

Hmmmmm is it because we are binning the GFS is because it's not what we want

 

[Spah1]

21 minutes ago, Iceaxecrampon said:

Its going to be a long winter for us lowland Fylde Coasters!

.....altitude is calling

Iain

Yep Chorley (Lancashire) no good in Eastetlies. 

Still hoping for battleground scenarios where the Atlantic pushes in but doesn't Win! 

[booferking]

You can see with the 06z mean that heights are not as good and i slight push West with the Atlantic low hopefully this changes 12z to better heights pushing East for a longer lasting cold spell..

[winterof79]

Post deleted

Edited December 5, 2018 by winterof79
Not adding anything

[Mokidugway]

Signs of NAO going positive

[That ECM]

7 minutes ago, Skullzrulerz said:

Hmmmmm is it because we are binning the GFS is because it's not what we want

 

Some are binning the gfs run because of the detailed reasons they have given.  No different to being sceptical of very cold run that turns out to be an outlier. 

Edited December 5, 2018 by That ECM

[matt111]

10 minutes ago, Skullzrulerz said:

Hmmmmm is it because we are binning the GFS is because it's not what we want

 

There’s a few detailed posts about it showing why it’s implausible. 

Edit: As @That ECM said before me above. 

Edited December 5, 2018 by matt111

[frosty ground]

Looking at the ensembles there are more than enough runs that back the Op for the Op to be taken seriously. 

[weirpig]

  

Left Parra   difference with the low   also parra brings snow as early as wednesday   loads to be resolved

Edited December 5, 2018 by weirpig

[frosty ground]

You can see the scatter has increased in the short term

[frosty ground]

Even the GFSP over runs the block to the east

[weirpig]

1 minute ago, frosty ground said:

Even the GFSP over runs the block to the east

It does  also with that vicious low   still way to far out  for any scenario to be favourite  

[Had Worse]

36 minutes ago, Iceaxecrampon said:

Its going to be a long winter for us lowland Fylde Coasters!

.....altitude is calling

Iain

You have altitude... its called Blackpool tower. Seriously though being close to the Irish sea is going to need some really cold air to see settling white stuff. I think more possible looking at the setup this year... we'll see.

[Met4Cast]

Okay because some are still struggling.. the reason i'm binning the 6z GFS is as follows.

120hrs the low is a weak area of low pressure leaving the Eastern Seaboard

 

144 it's deepened fairly rapidly, (gfs left) note UKMO (middle) and GFS(P) (right) are both much shallower than the GFS at the same timeframe

GFS 180, the low has deepened extremely 

The run then goes on to sit the low there and spawn secondary lows from it into the UK, blasting the block away as if it didn't exist. This is a very known GFS bias, one that does appear to show up on the 6z more than other runs for some reason. Lets take a look at the ensemble mean

Yep, shallower and more inline with the ECM/UKMO/GFS(P).

Control run?

Also shallower. GFS op has no support for the rapidly deepening low nor does it have any support for blasting the block away the way it does so. So. A few of us aren't "binning it because it doesn't show what we want", we're binning it because it's unrealistic, it's a known and understood bias within the model and it doesn't have support from any other models.

Hope that explains things a little better.

[Met4Cast]

To add - 

GFS Para gets low pressure into the UK but it's much further South than the previous run, we want the trend Southwards to continue (ignore the overblown low yet again, likely to be shallower in reality) 

Note: The block hasn't been blasted away, it's still sat there.

Atlantic influence towards day 10 is supported within the EPS so it's a growing consensus at the moment, don't forget though that models struggle to disrupt energy SE underneath Scandi highs, ensembles struggle even more. The trend short-medium has been to correct the high West and as seen in the GFSP, correct energy South.

[Matthew.]

6 minutes ago, frosty ground said:

Even the GFSP over runs the block to the east

Yes a key period. The ECM showed Wednesday later on looks the peak day for the easterly when some may see a wintry mix but no sign of lying snow for those without elevation

[The Eagle]

6z GFS not a rouge according to the FV3 run. Just a bit too much energy through the Atlantic.

 

NAVGEM same.

Not the best 6z suite overall.

 

[winterof79]

These two stills show energy going south/ south east. Scandi heights are going to be there for some time

 

[frosty ground]

7 minutes ago, Daniel Smith said:

Okay because some are still struggling.. the reason i'm binning the 6z GFS is as follows.

120hrs the low is a weak area of low pressure leaving the Eastern Seaboard

 Removed long post 

Surely that Low is exploded becasue of the temperature gradient

 

A normal reaction 

[Met4Cast]

The clusters are as clear as mud.. 4 clusters at just T144 though all broadly showing the same pattern

5 by 240 showing the support for the Atlantic as seen on the EPS means in cluster 1

Though all still showing a rather extensive blocking signal but no huge % number on any of them.. So overall, huge amounts of uncertainty, no point worrying about a single 6z run then.

Edited December 5, 2018 by Daniel Smith

[Methuselah]

27 minutes ago, That ECM said:

Some are binning the gfs run because of the detailed reasons they have given.  No different to being sceptical of very cold run that turns out to be an outlier. 

IMO, once the scatter drowns out any genuine signals, all the ensemble members are implausible - not just the ones that don't show us what we want to see..?

But I like uncertainty; it's what makes weather-watching so enthralling...

Edited December 5, 2018 by Ed Stone

[frosty ground]

Looking at the Ensembles from 192 onwards, only 3 hold the block in place to affect the UK and not for a long time, all the ther push the block east and the atlantic rolls through. 

The op has support bin it but don't be surprised if the 12z suites continue this trend and do not be surprised if they don't

[SLEETY]

26 minutes ago, Mokidugway said:

Signs of NAO going positive

Ties in with what their seasonal forecaster said on the METO youtube channel,i’m afraid .Due to positive warm waters anamoly off the East coast of USA.Expect more sustained blocking later in winter seems to be the way this winter is heading.

 

 

 

[That ECM]

Just now, Ed Stone said:

IMO, once the scatter exceeds any genuine signals, all the ensemble members are implausible - not just the ones that don't show us what we want to see..?

Hi Ed, not sure that they are  all implausible, the right one is probably in there. It’s impossible to know which one is the right one