Model output discussion - Winter has arrived

[sheikhy]

Changes on the 12z!!!ukmo slides again!and gfs backing west each run!!!

[SMU]

GFS still broken from 144 *however* hoping noone will notice, without telling anoyone look at the correction west in 24 hours

Lets review how much more it jumps tomorrow

Also look at the polar heights increasing

12z today first

Edited December 6, 2020 by Steve Murr

[nick sussex]

Quite a good UKMO output .

The day 7 would see the top low moving nw and the bottom one moving more se.  Pressure should build sw towards Iceland as the top low clears nw .

The GFS is less progressive than recent runs in its earlier part of the run but still looks very poor in comparison .

[IDO]

Good consistency from the GFS op, right or wrong, it is not playing switcher-roo:

06z>> 12z>> 

Six similar runs and counting! Those dartboard lows may not be a sign of algorithmic tomfoolery but simply four lows merging and being squeezed by opposing forces? 

Assuming GFS is right with the above, it's ens were very unsure of what happens as the Atlantic ridge topples post-d8...

 

[SMU]

4 minutes ago, nick sussex said:

Quite a good UKMO output .

The day 7 would see the top low moving nw and the bottom one moving more se.  Pressure should build sw towards Iceland as the top low clears nw .

The GFS is less progressive than recent runs in its earlier part of the run but still looks very poor in comparison .

Yes. Indeed.

 

2 minutes ago, IDO said:

Good consistency from the GFS op, right or wrong, it is not playing switcher-roo:

06z>> 12z>> 

Six similar runs and counting! Those dartboard lows may not be a sign of algorithmic tomfoolery but simply four lows merging and being squeezed by opposing forces? 

Assuming GFS is right with the above, it's ens were very unsure of what happens as the Atlantic ridge topples post-d8...

 

Chance of verification. 5%
 

UKMO / GEM / ICON / ECM all split the low.

So not sure why any logical person would choose to forecast based on the GFS when since 2001 its always made the same errors when energy is split...

[Scott Ingham]

28 minutes ago, Eskimo said:

Your absolutely correct, that's why I've frequented this place for the better part of 10 years - the difference of opinion is what drives interesting conversation. However, an alternative view, especially as we are predicting the future with no certainty isn't pessimistic, just different, and both views should be respected. 

The view is respected. But my view that it's pessimistic must also be understood and respected. That's my opinion. I believe its a glass half empty approach to them charts

[Allseasons-Si]

3 minutes ago, Steve Murr said:

Yes. Indeed.

 

Chance of verification. 5%
 

UKMO / GEM / ICON / ECM all split the low.

So not sure why any logical person would choose to forecast based on the GFS when since 2001 its always made the same errors when energy is split...

Lest not forget the mighty NAVGEM 06z

@ 144 and 180.

great ICON though Steve

 

[IDO]

5 minutes ago, Steve Murr said:

Yes. Indeed.

 

Chance of verification. 5%
 

UKMO / GEM / ICON / ECM all split the low.

So not sure why any logical person would choose to forecast based on the GFS when since 2001 its always made the same errors when energy is split...

GEM def slowly moving towards the GFS by d7, so maybe the small differences pre-d6 will make little difference in the medium term?

GEM>>  gfs>> 

Certainly a synaptic match though dynamics different as they have arrived there by different routes?

[mountain shadow]

The 12z UKMO t+144 northern hemisphere view is not your usual December view.

I just hope we actually get something worthwhile out of it.

[SMU]

Yes ^^
Maybe we shouldnt dispute the possibility of some phasing of low pressure making a deeper low however what the GFS will always do is place it as far NE as possible.

Assuming the 96 > 120 Evolution is correct GFS has already failed at the first attempt ( as did 1 UKMO the other day & I think 1 ECM ) however these quickly resolved the right 'type' of evolution.

@IDO In terms of corrections it seems only to be you & WIB not noticing the GFS make its usual corrections > even though they are clearly highlighted. 

Its no point in going on about the GEM at day 7-8 if the GFS is wrong at day 5-6...

Some posters here follow 0 logic. Still after all these years choosing to follow the GFS at the worst possible moment.

Of the overall scenario blend tonight you might use 10-20% GFS info if you are lucky.

Edited December 6, 2020 by Steve Murr

[dragan]

3 minutes ago, Steve Murr said:

Yes ^^
Maybe we shouldnt dispute the possibility of some phasing of low pressure making a deeper low however what the GFS will always do is place it as far NE as possible.

Assuming the 96 > 120 Evolution is correct GFS has already failed at the first attempt ( as did 1 UKMO the other day & I think 1 ECM ) however these quickly resolved the right 'type' of evolution.

@IDO In terms of corrections it seems only to be you & WIB not noticing the GFS make its usual corrections > even though they are clearly highlighted. 

Its no point in going on about the GEM at day 7-8 if the GFS is wrong at day 5-6...

Some posters here follow 0 logic. Still after all these years choosing to follow the GFS at the worst possible moment.

Of the overall scenario blend tonight you might use 10-20% GFS info if you are lucky.

great post. seems like there is no where we can head but milder south westerlies for the foreseeable, HOPEFULLY things change for the  colder sometime after day 8-10

[phil nw.]

The Atlantic lows again struggling to get past S.Greenland,coming up against the block to the east.

GFS again slight correction west with the ridging across the north.Steve M making the point with his charts .

Those of us who have observed over the years almost expect this with GFS especially in this situation where the energy gets split against the block.GFS seems to just favour a little more in the northern arm.

Again though i am aware in this pattern where we have a weak Atlantic v Russian block that ebbs and flows reliability probably 4 days before divergences in fine detail make a big difference down the line.

Still a very unusual NH profile though with the vortex looking distinctly under par for December.

 

[SMU]

6 minutes ago, dragan said:

great post. seems like there is no where we can head but milder south westerlies for the foreseeable, HOPEFULLY things change for the  colder sometime after day 8-10

On the contrary. It depends how far back west the phasing is. As the ICON highlights total days with SWs > 1 at a push.

[tight isobar]

@reminder.. good polar profiles- but we ourselves need a dip and mid point profile/@ defined heights at lower based arctic momentum.. otherwise it’s hit then MISS for our part as any spillage dribbles west-east.. an easy explanation of how all the numbers have to align in our lottery (in it to win it)-  process... the points are there.. but need scrutiny.... on we go..!!!

[feb1991blizzard]

10 minutes ago, Steve Murr said:

Yes ^^

You are always 100% right about the GFS, 0 chance of it verifying against all other suites when just sending a train of energy on a SW to NE axis, however, this still doesn't get me a right tonking of snow, any sliders are likely to be rain / slush like this last one, until either some really low dep points and 0c surface temps undercutting properly a band of PPN at a favourable angle, or some proper uppers, the latter impossible at anytime before New year i would wager.

[Scott Ingham]

19 minutes ago, Steve Murr said:

Yes ^^
Maybe we shouldnt dispute the possibility of some phasing of low pressure making a deeper low however what the GFS will always do is place it as far NE as possible.

Assuming the 96 > 120 Evolution is correct GFS has already failed at the first attempt ( as did 1 UKMO the other day & I think 1 ECM ) however these quickly resolved the right 'type' of evolution.

@IDO In terms of corrections it seems only to be you & WIB not noticing the GFS make its usual corrections > even though they are clearly highlighted. 

Its no point in going on about the GEM at day 7-8 if the GFS is wrong at day 5-6...

Some posters here follow 0 logic. Still after all these years choosing to follow the GFS at the worst possible moment.

Of the overall scenario blend tonight you might use 10-20% GFS info if you are lucky.

Very well put. I thought I was being polite calling it pessimistic! Its verging on trolling so rightly should be pulled up as these posters have been on here long enough to know the GFS always finds it impossible to resolve split flow from the jet

[northwestsnow]

Owwwwww Scott you are going to ruffle some feathers in here !!

Anyway, GFS is just plain awful.

Next !! 

UKMO not sure ...

[Scott Ingham]

1 minute ago, northwestsnow said:

Owwwwww Scott you are going to ruffle some feathers in here !!

Anyway, GFS is just plain awful.

Next !! 

UKMO not sure ...

I am overly opionated and straight to the point! 

Let's see where ECM stands. There will be a warm up i feel but not from low pressure barreling through. More likely WAA pushing through the heart of the country in week 2

[I remember Atlantic 252]

7 minutes ago, northwestsnow said:

Owwwwww Scott you are going to ruffle some feathers in here !!

Anyway, GFS is just plain awful.

Next !! 

UKMO not sure ...

Still I'm absolutely convinced it will settle down with high pressure from the 20th, 'guessed' this in my Dec CET thingy, now how cold or mild who knows,

[IDO]

The gefs at d8 are a poor bunch, certainly no undercuts of any worth and pretty much moved towards the op over the last few runs. The mean sums it up:

d8 mean>> gefs>>

Hopefully, as others say, this is another gfs fail, and that its steadfast trend is totally wrong?

[swfc]

20 minutes ago, IDO said:

The gefs at d8 are a poor bunch, certainly no undercuts of any worth and pretty much moved towards the op over the last few runs. The mean sums it up:

d8 mean>> gefs>>

Hopefully, as others say, this is another gfs fail, and that its steadfast trend is totally wrong?

Strangely its shown over the years some epic cold spells that were drooled over early doors and fi? Guess the proof will be in the pudding over the coming days  BTW Jamie vardy your a true legend

Edited December 6, 2020 by swfc

[I remember Atlantic 252]

1 minute ago, General Cluster said:

Time for a spot-the-beast competition... Is that a polar bear?

   

General Custer and his usual 384 chart! fairly accurate I'd say, we know HP will be in charge, until 02 Jan, question is where

[SMU]

I will do the usual MEAN tracker for the GFS from 168 -96 to see how it performs. I startes on the 06z 168 > then have the 162 12z.

Forecast. Expect the deep low pressure to track South West.

[nick sussex]

Something. to bear in mind with the GEFS .

Those can at times have a progressive bias and it’s not just an operational run scenario .

Thats been highlighted by forecasters in the USA . Whether it’s right now time will tell but blocking scenarios aren’t really its forte .

Edited December 6, 2020 by nick sussex

[booferking]

Liking EC already early doors much more like ukmo with first low even better actually .

Edited December 6, 2020 by booferking