Model Output Discussion 01/09/17

[SMU]

So, back in the room-

Note for All- GFS bias to over estimate the heights in euro low heights-

see this chart

 

take the bias out its identical to the ECM

 

GFS bias-

overestimate euro heights by 8-12 Dam

over estimate upper air cold pool by +4c

watch both those values drop over the next 72-96 hours....

S

[tight isobar]

2 minutes ago, Steve Murr said:

So, back in the room-

Note for All- GFS bias to over estimate the heights in euro low heights-

see this chart

 

take the bias out its identical to the ECM

 

GFS bias-

overestimate euro heights by 8-12 Dam

over estimate upper air cold pool by +4c

watch both those values drop over the next 72-96 hours....

S

And they will...

All laid on for the drop!!!

But its twitchy!!

[blizzard81]

Some incredibly negative posts in the last half hour. Honestly, what do people want? We don't live in Canada. It is November, northeries will very rarely be as cold at this time of year as the one's we are about to experience. If you don't believe me, look at the archives. Look at the same synoptics in Nov 62 for example. I am not having a go here. I am merely trying to make some members on here see what is right  before their eyes. A significant cold spell for late November. 

[karlos1983]

Like bloody MI5 In here tonight. 

Anyone good with code because my brains hurting 

Edited November 25, 2017 by karlos1983

[Nick F]

26 minutes ago, northwestsnow said:

 

PS look how cold  Southern Norway is!! Im sure i heard some folk say there is no cold air to tap into..

That part of Norway is high elevation / mountains just inland, hence low temperatures shown which aren’t reflective of sea-level.

T850s don’t always truly reflect the surface temperatures by rule of thumb of course, though the air on arrival in UK after crossing over the North Sea at the time of your chart will be modified somewhat compared to when it left Scandinavia. 

Edited November 25, 2017 by Nick F

[That ECM]

Look at the lack of jet stream and lack of cold us/Canada side. Has to be encouraging.

[damianslaw]

Models this evening a variation on the same theme, i.e. a blocked atlantic, a weak ineffectual PV, significant amplified flow, energy in the southern arm of the jet, arctic height rises, a rapidly cooling continent = all factors pointing to a potentially protracted cold spell, the caution though is the time of year, this is the least likely part of the year to see a weak atlantic, it is therefore always a taller order to see lengthy cold blocked periods now, than in the second half of the winter - with this in mind, the northern hemisphere is certainly far from its normal base state in late November - very notable.

I commented previously how the last time we had blocked conditions at this time of year fending off the atlantic was 2012, prior to that 2010, then 2008, all were followed by some notable cold wintry conditions, 2010 admittedly ended up very different to 2008/2009 and 2012/2013.

ECM in particular has for days now, been firm on an extended lengthy cold period, GFS has stuttered but the balance has been on cold. 

And a word on uppers, we had snow early this morning, we had snow early Friday morning, in uppers only around -2 - -3 degrees and thicknesses not much below 528 dam, and no trough or frontal features.. 

[Tracy Flick]

The JMA is chilly from Tuesday all the way to +264h.  Unfortunately it's mostly dry too.  216h and 264h:

[karlos1983]

9 minutes ago, That ECM said:

Look at the lack of jet stream and lack of cold us/Canada side. Has to be encouraging.

My worry is the jet pacific side, take last week, for example in comparison to the one you’ve posted. 

a jet that is “meandering” (sorry if wrong term but it’s late) creates that same pattern down stream. From what I understand, a strong jet pacific side, isn’t something that will help us down stream. I may well be wrong, just sure I’ve read that somewhere.

im not being negative either, I’m perfectly happy with next week, but as always, want more. That’s called human nature. 

Edited November 25, 2017 by karlos1983

[Kieran]

Atlantic still blocked up to day 10.

Quite rare to see Synoptics like this for early December...

[Derecho]

OK quick comment on the 18z, not too bad, again cold in the middle of next week but some milder air threatens to filter through as the high sinks, will still be on the chilly side though.

That high to the NW at T240 is mighty impressive but we must not get height rises over Italy otherwise It'll be no use, it could encourage cold air to fall to our west unless the high gets shunted away. Nevertheless that's way into FI.

Upto T240 I give the 18z 6.5 out of 10 snowflakes

Edited November 25, 2017 by Quicksilver1989

[feb1991blizzard]

All aboard the west based -NAO train, I was hoping (and indeed thought it was going to) to demonstrate with the 18z why the retrogression train is a better bet than the Easterly with some frigid uppers, it still might 300+

[Ian Francis]

Isn't Newfoundland an unusual neck of the woods for a high, such as modelled in the later stages of the GFS 18z? 

[SMU]

Remember 9th Dec is peak opportunity for blocking ?

[Kieran]

Here's a question to some of you with more knowledge than I: 

If the 18z run was to verify with mostly a slack cool north westerly flow - what sort of CET would December be up to around the 10th? Seems like this is the favoured pattern now amongst the models.

[Frosty.]

Too much emphasis on when the cold might end rather than enjoying  it while it's here! 

The Gfs 18z shows a cold wintry spell after Monday with sleet and snow, frosts and ice  and it's not even winter yet.. enjoy what we get is my message

[blizzard81]

8 minutes ago, feb1991blizzard said:

All aboard the west based -NAO train, I was hoping (and indeed thought it was going to) to demonstrate with the 18z why the retrogression train is a better bet than the Easterly with some frigid uppers, it still might 300+

Cast your mind back to last week when so many outputs were gunning for a west based nao for the current cold spell. I will say no more

[tight isobar]

Taking one run..12z..

Gfs.

And looking at jet-profile.

Its not a great deal for block/establish..

Nor profile of cooling impending.

'However'.

Current output in compare..

Has the ridge/and complient 'advection' suitable.

So take the overall prognosis as an evaluate...

Not a run-on-run..

Dividing' complex issues' and data via raw output....is going crazy for cold.

And increasing to the format!

And i have purposely.. taken the given worst prognosis' via jet/hemis' profile.

Edited November 25, 2017 by tight isobar

[feb1991blizzard]

2 minutes ago, blizzard81 said:

Cast your mind back to last week when so many outputs were gunning for a west based nao for the current cold spell. I will say no more

but the initial cold plunge was west based, point taken though these are more likely to correct East than West nearer to the event.

[lawrenk]

2 minutes ago, tight isobar said:

Taking one run..12z..

Gfs.

And looking at jet-profile.

Its not a great deal for block/establish..

Nor profile of cooling impending.

'However'.

Current output in compare..

Has the ridge/and complient 'advection' suitable.

So take the overall prognosis as an evaluate...

Not a run-on-run..

Dividing' complex issues' and data via raw output....iys going crazy for cold.

And increasing to the format!

I can see where you’re coming from. 

[bluearmy]

8 minutes ago, blizzard81 said:

Cast your mind back to last week when so many outputs were gunning for a west based nao for the current cold spell. I will say no more

It has been a west based neg nao - we just had a week of dropping NAO down to -3 and it corresponded to almost record mild temps in e England! 

[Nick F]

Wouldn’t be too despondent over the 12z and 18z GFS op desire to introduce less cold air from the NW and W. The 12z EPS Clusters don’t inspire all out confidence for the idea of the high res runs this evening to lose the ridge influence to the north and bring in troughing from the NW and back the flow to a NWly later next week and weekend. 5 clusters, which indicate we could go down this path or we could see Atlantic ridging build strongly enough NE to block troughing extending down from the NW. No clear signal yet, albeit we are entering a blocky pattern and the models are always keen, often too keen, to break blocks down.

 

[tight isobar]

Jet-profile in /compare.

12z..

18z.

The jet is a a confusion of synopyic!

Ridging/counter ridging' side by side with counter' confuse..

Shortwave-v- un-decipher migrate!..

And a northern hemisphere state' not only of flux..but dire confuse..as much as the ground beyond the troposphere!.

If weather done soap-op..

The whole country would be glued....

But its just us sad bast###s!

Edited November 25, 2017 by tight isobar

[Northern Sky]

1 hour ago, karlos1983 said:

Ok then but you’ve totally lost me 

(genuinely concerned your account has been hacked)

I like tight isobar's posts. I'm starting to think his computer has learned to talk for itself.

[snowbunting]

Its the heights over Greenland that are truelly astonishing. Promising lots of Nly outbreaks. One of these is going to create fun and games.