Model Output Discussion 19th January 2014-18z onwards.

[Weather of Mass Disruption]

Best hoped for a Western - NW UK bias in the short term from the alleged poor 06Z GFS - I am refusing to look long term as the disappointment continues......

 

uksnowrisk.png

 

Meanwhile Helvellyn at (less than 3k ft)

 

 

14012110tom_heights.jpg

 

 

Nice but at altitude  - and a hard slog to be in it.

 

Ian

 Now that it is a lovely sight! Climbed it back in March and the mighty striding edge

[Catacol]

A bit concerned today as we enter the crucial phase of the winter this year. Previously my optimism was centred around an increasingly disrupted vortex - this optimism continues. But... we have a signal now for the main core of the vortex to transfer back towards the Canadian side come the end of the month. This is not good... and while there are still 2-3 weeks of good winter potential to come after 1st Feb it will not help build the pressure over Greenland that MJO phase 6 into 7 would suggest.

 

Here is the 50hPA chart at 144: note the split energy favouring greatest energy more on the siberian side:

 

 

But then the 240h chart with a clear move back towards Canada:

 

 

Vorticity plots at the same period also show a signal for continued cyclogenesis over the NW atlantic

 

 

... and while we have a clear signal for the arctic high on this chart we also still have zonal wind speeds at 60 degrees north that are not suggesting a blocked pattern

 

 

This is all reflected in recent ECM op runs like the 0z where the global pattern really isnt very good for us at all with the signal for any blocking over Greenland or Scandy very muted:

 

 

Hoping that this is wrong. Interesting that Fergie is referring to a tipping point: I assume ECM output today represents the wrong side of that tipping point for us. Are our chances of cold patterns in "real" winter on the slide? Perhaps one sign of hope: JMA MJO plots send us into phase 8 by the end of the month:

 

 

with a corresponding composite thus for January:

 

 

and this for February:

 

Edited January 22, 2014 by Catacol_Highlander

[fergieweather]

 

This is all reflected in recent ECM op runs like the 0z where the global pattern really isnt very good for us at all with the signal for any blocking over Greenland or Scandy very muted:

 

 

Hoping that this is wrong. Interesting that Fergie is referring to a tipping point: I assume ECM output today represents the wrong side of that tipping point for us. Are our chances of cold patterns in "real" winter on the slide?

The last EC monthly (Mon) painted a strong signal for low height anomalies stretching right across from Iceland to the east of Scandinavia by mid-Feb, after cold UK anomalies rest of January get replaced by a more average signal into mid-Feb (and positive temp anomalies returning across eastern/NE Europe). Individual postage stamps offer a raft of possible types within this regime by 1-2 week February, including cyclonic N/NE/E'rlies, but with mean flow broadly westerly to NW. There's no discernable signal for blocking to the NE after January (heights there fade east) but the cyclonic wintry options mean nothing can be ruled-out regarding potential for noticeably colder spells. Whilst varied folk snipe rather vacuously at the EC32 (presumably without actually examining the whole suite in detail, including the clusters/stamps/plumes), it has to be noted how it's broad performance thus-far since early-mid December has actually been very solid, not least in sticking doggedly to the mobility that has indeed dominated since before Christmas. Shannon entropy is markedly high (i.e. in other NWP suites used by UKMO) during this weekend and into start of next week. Thereafter, the agreement actually improves and entropy falls (i.e. for a return to a westerly-dominated cyclonic pattern; this thus driving moderately high confidence in the switch back to a familiar pattern (as expressed in UKMO public web forecasts). However, the key issue is what happens Sun-Tues with the exit of the low to the SE, as this very much drives the fortunes (colder or otherwise) for the nearer-term and for now, despite the 00z output of other op centres, UKMO are sticking with the potential of a marked easterly phase being very much a possible outcome yet to be discounted. All to play for. Edited January 22, 2014 by fergieweather

[MPG]

 The last EC monthly (Mon) painted a strong signal for low height anomalies stretching right across from Iceland to the east of Scandinavia by mid-Feb, after cold UK anomalies rest of January get replaced by a more average signal into mid-Feb (and positive temp anomalies returning across eastern/NE Europe). Individual postage stamps offer a raft of possible types within this regime by 1-2 week February, including cyclonic N/NE/E'rlies, but with mean flow broadly westerly to NW. There's no discernable signal for blocking to the NE after January (heights there fade east) but the cyclonic wintry options mean nothing can be ruled-out regarding potential for noticeably colder spells. Whilst varied folk snipe rather vacuously at the EC32 (presumably without actually examining the whole suite in detail, including the clusters/stamps/plumes), it has to be noted how it's broad performance thus-far since early-mid December has actually been very solid, not least in sticking doggedly to the mobility that has indeed dominated since before Christmas. Shannon entropy is markedly high (i.e. in other NWP suites used by UKMO) during this weekend and into start of next week. Thereafter, the agreement actually improves and entropy falls (i.e. for a return to a westerly-dominated cyclonic pattern; this thus driving moderately high confidence in the switch back to a familiar pattern (as expressed in UKMO public web forecasts). However, the key issue is what happens Sun-Tues with the exit of the low to the SE, as this very much drives the fortunes (colder or otherwise) for the nearer-term and for now, despite the 00z output of other op centres, UKMO are sticking with the potential of a marked easterly phase being very much a possible outcome yet to be discounted. All to play for.

So a medium term cold shot could be possible, but the longer output trend is back to sqaure one regarding any blocking to the north? Lets hope this LP dives SE! ouch.

[MR EXTREMES]

An anodine update from METO today with a hint of a colder easterly for the NE and a period of colder weather generally before things settle down.

Not much mention of anything particularly wintry later on apart from some frost & fog. No real snow prospects for the bulk of lowland UK - Could be worse.

 

ENS reflect this view quite well

so who right summer sun or yourself because your saying settled towards the end and ss is saying wet and windy ?

 

as for the met going with colder easterly in the north later next week that must mean that low pressure has found a path south southeast intresting so this would suggest they favour there own model in the mid term so in honesty anything can happen.

[seabreeze86]

GFS different upstream on the 12z, Deepens the small low coming down the spine of the states lest hope it pulls more energy south, therefore slowing the main chunk of energy down and allowing the Azores high to split the energy coming across the Atlantic

 

Lets wait and see

 

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014012212/gfsnh-0-96.png?12

[Purga]

 

The last EC monthly (Mon) painted a strong signal for low height anomalies stretching right across from Iceland to the east of Scandinavia by mid-Feb, after cold UK anomalies rest of January get replaced by a more average signal into mid-Feb (and positive temp anomalies returning across eastern/NE Europe). Individual postage stamps offer a raft of possible types within this regime by 1-2 week February, including cyclonic N/NE/E'rlies, but with mean flow broadly westerly to NW. There's no discernable signal for blocking to the NE after January (heights there fade east) but the cyclonic wintry options mean nothing can be ruled-out regarding potential for noticeably colder spells. Whilst varied folk snipe rather vacuously at the EC32 (presumably without actually examining the whole suite in detail, including the clusters/stamps/plumes), it has to be noted how it's broad performance thus-far since early-mid December has actually been very solid, not least in sticking doggedly to the mobility that has indeed dominated since before Christmas. Shannon entropy is markedly high (i.e. in other NWP suites used by UKMO) during this weekend and into start of next week. Thereafter, the agreement actually improves and entropy falls (i.e. for a return to a westerly-dominated cyclonic pattern; this thus driving moderately high confidence in the switch back to a familiar pattern (as expressed in UKMO public web forecasts). However, the key issue is what happens Sun-Tues with the exit of the low to the SE, as this very much drives the fortunes (colder or otherwise) for the nearer-term and for now, despite the 00z output of other op centres, UKMO are sticking with the potential of a marked easterly phase being very much a possible outcome yet to be discounted. All to play for.

Many thanks as ever Ian.

 

I guess this is as per the hints in the 6-15 day update today where they state:-

 

"There may be a colder interlude around midweek, with easterly winds and wintry showers in the northeast of the UK."

 

The first time this has been mentioned recently - maybe there is a finite risk of this pattern shifting further SW?

 

One can hope...

[Summer Sun]

UKMO at t96 shows another nasty low west of Ireland

 

 

Heavy rain and Gales could be widespread again on Sunday and given the saturated ground flooding will be a concern 

 

GFS has the low even deeper

 

Edited January 22, 2014 by Summer Sun

[MR EXTREMES]

just goes to show even with a split vortex like this we still cant get nothing decent cold wise.

but im not convinced its a done deal for zonal onslaught.

Edited January 22, 2014 by emotional rollercoaster

[Summer Sun]

UKMO at t120

 

 

Coldest air staying east for now

[fergieweather]

GFS flapping around like a fish in terms of the evolution circa T+144... great run-to-run variability. Really does emphasise the difficulties in handling all that development in both this and other NWP suites....

[SMU]

Shocking consistency from the GFS-

 

open the current availabile chart ( about 138) & compare it with the 06z & you will see a totally different shortwave pattern & indeed the longwave is markedly diffrerent as well.

 

Of course when this all shakes out of the GFS runs will probably be near the mark- which will no doubt prompt calls that the GFS is king, when in reality its a shambles.

If its consistency your after pick the UKMO to 120.

 

S

 

PS Ian beat me to it.

Edited January 22, 2014 by Steve Murr

[Gaz1985]

Quite a big temperature difference on Friday, very mild across Ireland and the far west with 12c approaching SW Ireland, but much cooler further east and north you are.

 

[Panayiotis]

At 156hrs the GFS is much much better than the 06z: Low going SE, small patch of heights can hopefully stall that low leaving the US, so we can get some WAA into Greenland/Iceland:

Edited January 22, 2014 by Panayiotis

[Mucka]

So a medium term cold shot could be possible, but the longer output trend is back to sqaure one regarding any blocking to the north? Lets hope this LP dives SE! ouch.

 

That is pretty much what we would expect though looking at current output.

Remember the majority of EC32 members will not be going for a marked Easterly phase which the MetO have not yet ruled out (which itself would give us a few days of wintriness) so if the block to our N/NE proves strong enough to bring this phase in then they can already be pretty much discounted for longer term prospects and thus uncertainty an dthe chances of more prolonged blocking would increase.

What they do tell us is that we will struggle to get the block in place for any pronounced Easterly and if so then a return to a mobile westerly type will likely evolve from there - pretty much in line with expectation really.  

 

So far this evening the output is continuing to struggle to shift our trough S/SE into Europe effectively enough with diminishing high pressure to the North nad not enough amplification to the West.

 

 

UKMO  better than GFS out to 120 but no improvement on this mornings run.

 

Edited January 22, 2014 by Mucka

[The Eagle]

12z GFS is an improvement for coldies.

 

All be it incremental this is closer to what we want to see - North to South on the Jet

 

[SMU]

http://www.meteociel.fr/ukmo/runs/2014012212/UN144-21.GIF?22-17

 

RAW UKMO says ..... SNOW Showers For Many Especially the NE with -10c air arriving.

 

Post this atlantic energy will want to push close, setting up a classic battle ground scenario from the NW the angle pf the block looks suitable for sustainability with the classic V shape aiming at the atlantic ( & if you look close the energy looks to be west of the UK)

 

but thats far to far away.

 

S

Edited January 22, 2014 by Steve Murr

[Panayiotis]

UKMO at 144hrs and we get the easterly! Its hard to say where it will go from here however....

[tight isobar]

UKMO remains pretty consistent this evening GFS slowly gets its act somewhat together after 144, but again struggles to find its way back from the off licence with bleary drunken vision!

[Mucka]

UKMO at 144hrs and we get the easterly! Its hard to say where it will go from here however....

 

Yes very good consistency with this mornings run as has been said. If we could just back things West some and get more amplification upstream we could have last nights GFS  snow fest within our grasp with lows disrupting to our West SE. (Assuming the UKMO is on the right track of course)

Let's hope ECM and JMA go similar routes or can even improve upon it.

[Bobby]

Even if the low pressures dives down to the SE I can't see anything stopping the Atlantic powering over us again. Not enough amplification or proper blocking. Each run is just a variation on the same big picture theme.

 

UKMO 144

 

 

Only one way that stuff to the west is going, our way.

 

As on GFS

Edited January 22, 2014 by Bobby

[Cecil Hogmanay Melchett]

UKMO keeps the faith.

And GFS 12Z has trended in the right direction.

OK maybe not a big freeze but certainly the chance for some snow for parts of the UK.

Im that desperate i'll take a day of snow showers..

Even if the low pressures dives down to the SE I can't see anything stopping the Atlantic powering over us again. Not enough amplification or proper blocking. Each run is just a variation on the same big picture theme.

 

UKMO 144

 

 

Only one way that stuff to the west is going, our way.

 

As on GFS

Lets ignore the fact that UKMO would bring snow showers for parts of the UK then Bobby?

PS GFS is actually a pretty wintry run

Edited January 22, 2014 by Cecil Hogmanay Melchett

[seabreeze86]

Great chart from the UKMO, snow showers for the east, where is goes from there i have no clue but after 53 days of winter without even a frost here i will take this.

 

http://www.meteociel.fr/ukmo/runs/2014012212/UW144-21.GIF?22-17

 

GFS all over the place at the minute. Lets hope the ECM is in a good mood today and follows the UKMO. Also if this turns out to be the correct pattern the JMA deserves so credit as its been banging on this drum for a couple of days now.

[Cheshire Freeze]

Yin and yang.....1048mb high to the NE and a 972mb low to the NW. The Azores high is doing us no favours at all...throwing ridges NE when really Atlantic energy should be sliding SE into the continent....

 

[Yarmy]

GFS flapping around like a fish in terms of the evolution circa T+144... great run-to-run variability. Really does emphasise the difficulties in handling all that development in both this and other NWP suites....

 

Much like the rest of us as these depressions keep torpedo-ing in. Anyway the UKMO T144 merits a minor BOOM IMBY.