Model Output Discussion - 05/01/2016 18z onwards

[Cheshire Freeze]

2 minutes ago, Swave Snow said:

Need to see more of the run 

It's pretty much an '09/10 copy so far up to day 8....watch the push from the NE day 9 behind that shortwave. Identical to Dec/Jan spell 2009 on this run. IDENTICAL.

Edited January 7, 2016 by CreweCold

[snowangel32]

Huge differences from pub run and 0z

0z welcome back Greenland high

 

pub run for comparison

 

 

[rory o gorman]

Far better WAA to Greenland on this run. Trough appears to centred further west though resulting in slower timing of deep cold. I wouldn't overly read into this though, focus on upstream.  

[Swave Snow]

5 minutes ago, CreweCold said:

It's pretty much an '09/10 copy so far up to day 8....watch the push from the NE day 9 behind that shortwave. Identical to Dec/Jan spell 2009 on this run. IDENTICAL.

Yup you are spot on there

[Cheshire Freeze]

Renewed WAA to strengthen block, meanwhile deep cold encroaches

 

[snowangel32]

3 minutes ago, rory o gorman said:

Far better WAA to Greenland on this run. Trough appears to centred further west though resulting in slower timing of deep cold. I wouldn't overly read into this though, focus on upstream.  

Yh could be an interesting Fi PV being attacked from all sides. Details still up for grabs. But it's safe to say we can lock in the cold for next week at least. After that anything is possible but we are in the game big time.

[Cheshire Freeze]

2 minutes ago, snowangel32 said:

Yh could be an interesting Fi PV being attacked from all sides. Details still up for grabs. But it's safe to say we can lock in the cold for next week at least. After that anything is possible but we are in the game big time.

There is no PV....Siberian side attack on vortex continues along with Atlantic and Pacific. Thank you very much, I'll take that....

 

[SMU]

morning All

stella overnight GFS & UKMO - both have the reamplification at 144 over the states delivering the super high over GH

a slight chink with the evolution - day 6 sees the cold held over the north as winds hold westerly but this will sink south post that as the force of the jet will drive it that way-

S

[tight isobar]

The 00z suite sticking its fingers up at both the 18z ....and the Atlantic. ..

A world better...

Some good wedge cold spilling in

[rory o gorman]

4 minutes ago, snowangel32 said:

Yh could be an interesting Fi PV being attacked from all sides. Details still up for grabs. But it's safe to say we can lock in the cold for next week at least. After that anything is possible but we are in the game big time.

Yes , I would ignore the downstream modelling at this point as  synoptically it's quite unlikely  to be so slow given the amplification  . This as a  pattern is a very encouraging run for sustained cold. 

[Cheshire Freeze]

5 minutes ago, Steve Murr said:

morning All

stella overnight GFS & UKMO - both have the reamplification at 144 over the states delivering the super high over GH

a slight chink with the evolution - day 6 sees the cold held over the north as winds hold westerly but this will sink south post that as the force of the jet will drive it that way-

S

Watch the precip potential day 10 from SW

[snowangel32]

Nice run if I was nit picking I would like the trough further south and bit more west so we can tap into the real cold pool but otherwise a nice run by far better than that pub run. It's clear the gfs is really struggling though has it always struggled with blocking type scenarios or is it a recent thing.

[Cheshire Freeze]

Circa foot of snow Midlands & S parts of N England

 

[snowangel32]

1 minute ago, CreweCold said:

Circa foot of snow Midlands & S parts of N England

 

Time to get the shovel if that ever comes off. 

[rory o gorman]

Gfs finishes with a nor'easter , London becomes New York ... Again all arbitrary after 180 hours on specifics .Upstream is at 09/10 levels.  

[Cheshire Freeze]

2 minutes ago, snowangel32 said:

Time to get the shovel if that ever comes off. 

Some areas would need a JCB!

[tight isobar]

Good run..

00z packed with potential and prolonged spell of cold.

After the 18z suite wobble.

[Mucka]

Love the passion and the post Lorenzo, perhaps a asterisk here and there in place of letters to suit sensibilities though? 

Basic takeway from this morning  is that things still going according to plan but we are edging a little too far West for comfort in some output as the colder air gets held to our West and thus more modified with a greater Westerly component until the trough finally moves far enough East to turn winds more Northerly.

The UKMO is further West too this morning but the alignment of the rough is such that we get a better flow initially so still colder quicker on UKMO.

120h comparison UKMO, GFS

This has more to do with the orientation of the trough though rather than actual pattern being too far West so not a threat to overall cold pattern setting up, just details. If the air is cold enough it may actually enhance ppn anyway and initially the North and West will be best placed for snow.

GFS 144

Reasons to be cheerful.

By 168 GFS is reloading the Atlantic ridge and by 192 we have a fantastic Green;and block with the trough finally dragging in much colder air though that is not to say it isn't chilly before that.

Into deep FI and the ridge still holding with the low that has been held to the SW for so long finally breaking through and creating the Mother of all snow storms.

Obviously not to be taken seriously at that range but it does reinforce the idea that the low to our SW will likely come into play at some point post day 8.

All in all stunning output again this morning which flies in the face of the MetO's latest update for a brief cold spell but then winds returning to West with unsettled weather and average temps returning as soon as end of next week.

Edit

 

GEM cold out to day 10 where a low breaks through but that would give only less cold weather temporarily as a reload is on the way.

Not to be taken at face value but worthwhile noting that the current signal is to reload and maintain any Atlantic block.

Edited January 7, 2016 by Mucka

[West is Best]

Bloody hell that's a phenomenal 0z GFS run. Lots of us talk about the importance of a proper Greenland High, something which really goes back to Steve Murr's work on here almost ten years ago. Well, if you're looking for a true GH this is staggering: 1056mb showing up?! Blimey o' Reilly. That would be a blocking high of some proportions. And of course with it we pull in some dramatic lower uppers. I say 'we' but it would hit much of Europe.

Many a slip and all that, but it's looking good so far.

 

[joggs]

All eyes on ECM old faithful ;

[Mucka]

Re MetO forecast.

"Towards the end of next week unsettled and sometimes windy weather with mainly westerly winds may become re-established, although there is some uncertainty. "

That would be a breakdown by the 15th so a 2 or 3 day cold snap. The only possible way that can happen with a Westerly regime returning is either for the ridge to fail (and that looks nailed on) or for the trough to be too far West and so low pressure form on its most Western flank cutting off the cold air which may also erode the ridge on its Eastern flank allowing the Atlantic back in. (plausible but with little model support thus far).

If we can get this trough to behave itself in this evenings output as well then we should of cleared those potential hurdles and then it will be all about detail of how cold and where and when the snow falls. We can only assume they are being overly cautious although we also have to keep in mind they are the pros and have a lot more information than we have to go off.

GFS short ensembles Central England. Decent mean 850's of -5 from around the 13th but temperatures holding up at the surface until mid month,

 

Long ensembles, Just the odd dissenting run but solidly behind a long cold spell.

Love the GFS Op snow spike around the 18th!

Edited January 7, 2016 by Mucka

[rory o gorman]

14/21 ENS members go for a greenland / mid atlantic block , the slight concern exists with  a trend to a more westerly based height increase which hampers deep cold arriving . 

[SMU]

As we wait the ECM a scan of the ensembles reveals

* GFS control - probably the most sustainable cold spell in the UK since 1986 - with the UK in the grip of winter from day 5 out to day 16 with a snowstorm in the south & the North already under snowcover frozen solid -

Also ZERO sign of pattern relaxation with the cut off greenland high still very strong ....

* GFS mean all the way out to day 16 paints a negative AO ( wheres IDO !) & the mean is down to -2 to -4 over the UK still - however if the pattern actually verifies like that then then uppers would be colder....

its all about that reridging up over canada & up in the atlantic at day 6 & 7 - nothing else really matters other than that because if it does the cold has only 1 place to go - NW Europe...

S

[Ali1977]

ECM looking good at 120, let's hope it replicates last nights run with a connection to the Arctic high.

144 still good but the WAA is narrower, not sure where 168 will go. As some have mentioned, UK still in the cold air, but it is slightly west of us...

Edited January 7, 2016 by Ali1977

[Captain Shortwave]

Both the UKMO and ECM begin to bring the low near the Azores into play at day 6.

                         UKMO                                                                    ECM

        

 

I must admit this is the first point so far where I am starting to feel a little nervous about this as this potentially allows a push of warm air up from the south west. Luckily this type of interaction is something not resolved until the nearer timeframes.

ECM at day 7

A deep low approaching from the south west, certainly brings moisture into the mix at least for the southern half of the UK.

Edited January 7, 2016 by Captain Shortwave
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