Model Output Discussion - Stormy Period Inbound...

[phil nw.]

Quite a change away from zonal pattern of a few days ago in the models and it  looks like the cold will  dig in further come the week end.

A colder blip was showing in the ens for around mid-month for some time but who would have expected the outlook we have now?

The current cold polar maritime westerlies look like being being replaced by even colder Arctic sourced air in a few days.

A couple of the latest UK fax's to see t72 and t120 showing the change from the westerlies to a weekend northerly.

 

 

looking at similar charts from the 12z P and ECM that northerly comes straight from the high Arctic with uppers around -8c coming south from day 5.

 

It is already pretty cold and more areas further south, in addition to Scotland and N Ireland who already have seen snow this week, are now seeing some snowfall.In fact it's snowing here as i type.

This will be cut short later tomorrow as that deep low comes in.

 

It now only looks like a short break before the cold returns by the end of the week.The upper trough cutting se into nw Europe means it looks primed for some snow around the UK next week.

 

The trend to weaken the Atlantic jet has certainly  gathered pace over the last 24hrs and we are now looking at a decent cold spell as those +ve height anomalies start to gain a foothold to our north and north east over the next few days.

 

[Geordiesnow]

What happens after the weekend remains a big question mark but it looks likely it will remain on the cold side up to the weekend, nothing desprately cold(the -10hpa is not forecast) but cold enough for snow too fall at times. 

 

The detail is important, it looks a bit messy but we see the UKMO/GFS going for a more stright Northerly/NNE'ly whereas the ECM is more NNW'ly but there is solid agreement on this. 

 

It would be good too see the -10hpa finally enter the UK at some point, that is for me proper cold air especially if its from a Northerly source. 

[Nick F]

A look at the EPS vs EC deter for London suggests even the south entering a somewhat more sustained colder period from Sun 18th to around Thurs 22nd than we have now, by day and especially at night. There appears to be quite a few EPs a lot colder than the deterministic run, though the deter close to the average.

http://www.weathercast.co.uk/services/ensemble-forecast.html

Perhaps a nationwide cold spell from Friday through much of next week, nothing severe and perhaps marginal for snow given lack of direct Arctic deep cold feed, but none of the yo-yo cold to mild to cold that we are currently seeing as these Atlantic systems roll past. The upper flow is buckling and slowing down a gear with lows filling from the weekend, with the cold setting in.

Edited January 13, 2015 by Nick F

[SMU]

Of note is the GFS control - apart from slight timing issues its identical to the UKMO raw at 150- so its a good replicator of what UKMO would look like at 192

 

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=6&code=0&mode=0&carte=0

 

heres a clue- country wide snow event 168-192

 

S

[yamkin]

Please disregard the GFS 12Z & 18Z parallel runs tonight. Issue should be resolved by the Wednesday 14th Jan 12Z parallel run

[Mucka]

GFS 18z control a lot better than the Op at least.

 

 

Short ensembles 2m temp Central England.

 

 

Ninja'd by Steve

Edited January 13, 2015 by Mucka

[Mair Snaw]

As it always is in the UK lets get the cold here first then worry about the details for snow etc once the cold is here.. not only that I see a few post looking for the end to the cold spell that is not even started yet.... its always the same... but lets have level heads here lets get the cold in before we start looking for the mild to return..

[SE Blizzards]

Well, the Control doesn't support the Op at Day 8

 

Op

 

 

Control

 

 

 

Plenty of decent enough looking ENS too at Day 8

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=192&size=

 

Edit: beaten to it again by King Steve, and also Mucka this time. Must get my fingers to work a bit quicker! 

Edited January 13, 2015 by SE Blizzards

[Great Plum]

Please disregard the GFS 12Z & 18Z parallel runs tonight. Issue should be resolved by the Wednesday 14th Jan 12Z parallel run

Yamkin, where did you get this info from?

I presume Croydon is well gritted tonight

[yamkin]

Yamkin, where did you get this info from?

I presume Croydon is well gritted tonight

 

Info generated shows GFS parallel run is having issues on output which will be rectified by tomorrow's 12Z run.

Yep, gritters are out to treat A & B routes due to falling temps and snow 

[Mair Snaw]

Please disregard the GFS 12Z & 18Z parallel runs tonight. Issue should be resolved by the Wednesday 14th Jan 12Z parallel run

any reason why???? can you tell us all how you know this and where you get your info from to tell us all to just simply disregard 2 runs because you say so???

[Mucka]

See if I can beat Steve this time, parallel looking good so far.

 

[shaky]

Brilliant parallel so far and same as the 12z!! Heights stronger across greenland aswell!!

[shaky]

Absolute snowfest on the parallel run!! Similar to ecm and the control run of the gefs!!

[SE Blizzards]

See if I can beat Steve this time, parallel looking good so far.

 

 

 

 

Snow event maybe for Southern Counties as well on the GFS(p) at Day 7 ?

 

Edited January 13, 2015 by SE Blizzards

[SMU]

So stella dendrite ensembles tonight- if we get that slider at the right angle & a tadge of heights in situ over NW scandi- then a BIG easterly is on

 

all 192 charts

 

Control

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-0-1-192.png

PTB 2

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-2-1-192.png

PTB 4

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-4-1-192.png

PTB 5

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-5-1-192.png

PTB 6

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-6-1-192.png

PTB 8

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-8-1-192.png

PTB 11

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-11-1-192.png            ****** BEST*****

PTB 13

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-13-1-192.png

PTB 17

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-17-1-192.png

PTB 18

http://modeles.meteociel.fr/modeles/gens/runs/2015011318/gens-18-1-192.png

PTB 19

http://modeles.meteociel.fr/modeles/gens/run/gens-19-1-192.png

 

So that's 50% @ Cluster 1 at 192.-

 

S

[Mark Bayley]

So stella dendrite ensembles tonight- if we get that slider at the right angle & a tadge of heights in situ over NW scandi- then a BIG easterly is on

 

 

 

Wait till you see the parallel Steve!

[yamkin]

any reason why???? can you tell us all how you know this and where you get your info from to tell us all to just simply disregard 2 runs because you say so???

 

Why, I do not know. Just sharing info which was fed to me. Take care and have a good winter

Edited January 13, 2015 by yamkin

[Barry12]

There can't be cold...theirs no SSW and the MJO isn't favorable

 

if this cold spell does verify, it proves that cold can never be ruled out even if the NH profile/signals aren't great.

 

albeit there was some warming in the strat

Edited January 13, 2015 by Barry95

[PHLIPPY67]

Hoping you guys are right with those charts...

[chicken soup]

Of note is the GFS control - apart from slight timing issues its identical to the UKMO raw at 150- so its a good replicator of what UKMO would look like at 192

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=6&code=0&mode=0&carte=0

heres a clue- country wide snow event 168-192

S

...thats not a countrywide snow event looks like rain over the nw....and clear over cumbria and scotland.....if you look at the accompanying precipitation chart for that time period. Edited January 13, 2015 by chicken soup

[pages]

Well that the 18z parallel certainly cold and snowy throughout and ends with the best chart for long term cold seen this winter. 

 

 

[SE Blizzards]

GFS (p) starting to finally trickle out.

 

Boom or bust?

 

I'm going to be positive and say Boom!

 

This is a note to all negative people...

 

 

See, being positive does pay off 

[joggs]

Ithought the parallel was a write off tonight?

As in faulty.

Edited January 13, 2015 by joggs

[shaky]

Well the parallel has given us a pub run special! ! Long may the improvements continue tomorrow!! Hard to imagine that parts of the uk could be covered in quite a lot of snow by the start of next week!!