Model Output Discussion 17th Dec.2013-12z onwards.

[Cheshire Freeze]

 (with perhaps the exception of Crewe 'coldest winter since the Younger Dryas' Cold ) aware that this is likely to be a slow burner, if it is indeed a burner at all.

 

Is that display name possible or is it too long? Hmmm......lol

[Polar Maritime]

GFS continues the trend this morning with the Jet sinking South and High Pressure pushing North. The PV is looking much more seasonal.

 

 

GFS and ECMWF aren't a country mile apart by the 5th, So more stormy weather to come next week before a change to much colder weather if this trend continues.

 

Edited December 28, 2013 by Polar Maritime

[IDO]

Well the UK OP from last night was clearly under doing the Canadian vortex disruption SE to the UK. This morning the T120 has the vortex under more pressure from the GH and heights to the US west and we see more energy going to the UK lobe. 

 

UK T120 0z:   Last night (T144):  

 

So seemingly no early gateway to blocking.

 

Conversely the GEFS and op tend to have less energy (compared to last night) and some members (small) get some heights to the NE:

 

P13 for eg:  

 

But this slacker flow overall fails, and a consequence is the slower release of energy from the Canadian vortex means further ridging is delayed, and we are still looking at the end of FI for a change. GEM is synonymous of this and at T240 it is rather flatter than recent runs:

 

 Still potential but it looks like the longer road to cold.

 

At T240, on the GEFS, there is the s.Euro upper trough still predominant, eg P8:

 

But the AH has more success, mainly cutting off those low heights and keeping the surface flow going over the top with variations of the zonal theme:

 

eg P5:

 

So it remains as we were, a pattern change in the offing, that has potential, but no clear signal whether the UK will benefit from any cold seeping south.

Edited December 28, 2013 by i'm dreaming of...

[TSNWK]

Morning folks. UKMO still trying to build heights around Svalbard around 120 and 144 with the trough from the west being held up.

ECM also has some heights around Svalbard around 120 and 144 with some disruption over the uk at the same, before sending energy southeast towards italy. 216 actually looked a nice chart to me but 240 was a little disappointing as I thought more energy would have headed to the south east out to our west, instead it went east.

GFS still does not appear to be buying into raising heights to our north east adound at 120 - 168. It does look like the jet is continuing to drift southwards though and low res' the GFS is not without interest again, think that is 3 runs on the trot GFS low res has been interesting.

One thing all models do have in common is that the polar vortex is under presure and splitting up, that must be a good thing and with all those lobes of the vortex bouncing around we can expect various solutions to be offered on the models for a while yet. Not a bad start to the day in my view

Cheers

Edited December 28, 2013 by TSNWK

[Gibby]

Good morning everyone. Here is my interpretation of how I see events unfolding as we enter the first weeks of 2014 seen through the eyes of the midnight outputs of the NWP for Saturday December 29th 2013.

 

All models show a steadily weakening SW to West airflow with showers as pressure rises over the next 24 hours. A ridge of High pressure crosses East early tomorrow with an active frontal system moving quickly in from the Atlantic later tomorrow with increasing SW winds and heavy rain sweeping East across all areas late tomorrow and overnight. Over Monday showery weather returns behind a cold front before more rain on Tuesday and later on New Years Day maintain the very wet conditions with renewed floods likely as we move into the New Year in association with deep Low pressure areas close to or over the UK in temperatures close to average.

 

GFS takes us through the start of 2014 with a seemingly incessant barrage of Low pressure after Low pressure streaming in on a strong Jet flow and delivering spell after spell of heavy rain and strong winds with only brief drier weather in between, these most likely later when transient ridges of High pressure cross over briefly ahead of the next system.

 

UKMO today show Low pressure covering all of the Atlantic Ocean North of the Azores with strong SW to West winds and series of troughs crossing quickly East or NE in the flow. Areas of rain and showers will be heavy at times with strong winds too making for an unpleasant and wet start to 2014.

 

GEM also shows a sustained and prolonged wet period with Low pressure permanently present over or just to the North of Britain with fronts bringing spells of rain and showers repeatedly East in the strong flow throughout the runs later stages.

 

NAVGEM also shows no remorse with with spells of heavy rain too occurring in very strong WSW winds and temperatures close to average.

 

ECM today also paints a worrying picture for those looking for relief from recent floods as it indicates a very unsettled phase with frequent bouts of gales and heavy rains as trough after trough crosses East over the UK in strong to gale Westerly winds and temperatures largely near to normal.

 

The GFS Ensembles indicate the Atlantic remains in top gear as it continues to pummel the UK with Low pressure after Low pressure with rain and strong winds at times from all members with temperatures close to the long term mean.

 

The Jet Stream continues to blow very strongly out of the States and across the Atlantic towards Southern Britain for the next week or so. If anything it then slips very slightly South across France as the UK remains under a broad and deep Atlantic trough.

 

In Summary today if anything the resolve towards wet and windy conditions persisting has strengthened overnight. All models indicate some very worrying synoptics for those that are looking for relief from recent floods as next week looks thoroughly wet and stormy at times with strong winds reaching severe gale force in places. In Week 2 small changes to the far NE in the Arctic only serve to pull depressions even further down over the UK from GFS and landing us under a deep trough with further wet and sometimes stormy conditions through Week 2 as well. All other models just continue the incessant feed of wind and rain East across Britain too 10 days from now. We really do need a break from this pattern soon as flooding issues are going to become unprecedented if some of this morning's output verify..lets hope for some moderation in the theme soon.

[Frosty.]

According to the Gfs 00z op run we are heading towards a wintry spell between early / mid January with the jet digging further and further south, heights eventually rising to the north /north east, the jet alignment tilting northwest / southeast, increasing amplification & trough disruption  / undercut potential and gradually more and more arctic air injected into the flow...from a coldies perspective it's looking peachy further ahead...BRING IT ON

Edited December 28, 2013 by Frosty.

[bluearmy]

Praise The Lord - an ECM op fi in line with its ens mean !!

the 'flip flopping' of fi's is frustrating but the modelling keep trending back to the same place which is troughing to our nw slowly sinking across us as the AH pulls back west. To where becomes crucial. Recent trends have been to hold the Azores ridge for longer to our sw and with blocking to our ne, not yet established, the flow can happily swing ne. We had been looking at a ridge off the eastern seaboard to draw up the Azores ridge around the 4th/5th. This looks to occur now around the 7th. The reason for this delay must lie in the upstream pattern which has proved more resilient re the placement of the Canadian vortex. Although not certain by any means, it does now look like this will relocate further west for a time over hudsons, digging a trough into the american interior and forcing a ridge to its east/southeast and hopefully, the retrogression of the Azores ridge. the big questions then follow. Tbh, little point in picking an option. It all depends on how everything interreacts before the vortex reasserts itself in eastern Canada and throws another pulse of northern arm at us. it could be like nicks drawings from yesterday, it could involve the retrogressed Azores ridge being thrown north and cutting off the troughing our side, all down to timing and you can think about all the possibilities to follow. tbh, most of them are visible in the gefs members and have been for the past few days. Clearly, the pros expect the next pulse of jet to flatten the ridge, rather than undercut any heights into the Greenland/Iceland area. that would seem the most likey option, but with the AO having gone negative, there will be a decent chance this may not occur. and how far into Europe will our troughing have got with the residues of the Azores ridge holding to our south? Clearly, the middle part of jan is going to be dependant on the above (and possibly the latter part also). It's quite obvious why the pros are reluctant to go any further than stating it will get cooler.

[Frosty.]

 I love this chart.  ...this could be the trend, based on the last few met office updates looking further ahead..me thinks winter is coming 

Edited December 28, 2013 by Frosty.

[Polar Maritime]

Me to Karl   December seems to have dragged on forever this year with storm after storm, nice to see a change on offering by the experts and now showing in the models for the New Year.  We need to remember we are only 3.5 weeks into winter !

Edited December 28, 2013 by Polar Maritime

[PolarWarsaw]

People only need to take a look back as far as 9 months to realise, we are 3 weeks into winter with as much as 3 months of it left.

[lorenzo]

With GEFS plotting this as an AO, wonder if we are going to see some ensemble members to rival that outrageous control run at the end of November...

 

[legritter]

Still signs in the Models of colder air gradually feeding in over the UK in later charts .And with high pressure setting up over N/WEST russia a real worry as fronts and troughs stall or slow down possibly over us .But at this stage flooding becomes a real worry ,what happens out past 9/10 days in my opinion is not yet modeled so from a coldies wish list lets hope a block to our north /east sets up .All in all i feel some possible chances out there .

[weather eater]

Leaving aside the fluctuations of FI output which in two hours time is just going to offer another option for those who like to mull over synoptic evolutions in the search for a sustained cold spell, what we have in the immediate is a Smörgåsbord of low pressure systems barrelling across the Atlantic bringing lots more rain, rain that frankly we don’t need.

[nick sussex]

So today we see the big 3 models humbled in terms of their operationals, the Euros overplayed their Scandi ridge and the GFS was trying to drain away the entire PV vortex in Canada, however you expect better from the Euros so they get an F today!

I think we have to accept that the PV is simply going to be too strong in the next week as it moves se and sends another wave of zonal bombs eastwards.

Thereafter at least we're now seeing a consensus going forward, I've been very harsh on the ECM in recent weeks in terms of its post 144hrs output but its 240hrs chart is a decent representation of the NOAA anomaly maps:

The problem this week has been the movement of the PV se into the ne USA which scuppered any chance of the high to the ne edging sw.

NOAA suggest a retrogression signal in their 8 to 14 day outlook and this time the PV is not expected to relocate at the worst possible moment, even if some of its energy is released eastwards its not the nuclear option that its decided on for the next week.

[IDO]

The ECM mean highlights the hi-res problem. On the face of it the T120 mean has surface heights in the right region:

 

 

But you have the GH reacting with a splitting Canadian PV and that can only mean a positive NAO. So by T168:

 

 

The Atlantic is still forcing the pattern, pushing those heights to our NE,  Eastwards.

 

Other models back this, GEM mean eg, T120:   T168: 

 

At least till D10 before a lull in the positive NAO.

Edited December 28, 2013 by i'm dreaming of...

[SLEETY]

People only need to take a look back as far as 9 months to realise, we are 3 weeks into winter with as much as 3 months of it left.

yes indeed.look at march ,drifting snow even here on the South coast.

 

A lot of these forecasters that are  already writing off the whole of jan based on what a cpu is telling them, are going to

be eating a lot of crow if you ask me by then.

[kev238]

It is pretty clear that the overriding signal at the moment is for more of the same, albeit slightly less extreme.

I would be very surprised if anywhere in lowland England saw significant lying snow before the middle of January based on current output, the next ten days seems quite nailed on unsettled and wet and average; following that it would take time to get Synoptics that would be conducive.

This winter seems very different to the past few in terms of a roaring and powerful jet; it may well be a winter remembered for

Floods and winds

[Purga]

Despite the continuing strong signal for the exceptional zonal stormfest to continue, GFS shows a fantasy snowy end

 

Very unsettled and average temps from the ENS

[Severe Siberian icy blast]

Despite the continuing strong signal for the exceptional zonal stormfest to continue, GFS shows a fantasy snowy end

 

Very unsettled and average temps from the ENS

Each to there own purga.

But there's also a clear trend for lower precipitation toward the end of the run thank goodness , whether you see it or not , there is a change on the horizon , the jet sinking south , low pressure into Southern Europe is always a good sign , usually promotes high pressure to the north . A good 7-10 days of wet weather followed by a much colder second half of jan , into feb , and march of course . Which is normally when our cold weather comes anyway, this will be winter of two very different half's I feel

[No Balls Like Snow Balls]

The models show more of the same theme. Lots more rain and wind to come next week. No sign of cold and snow away from Northern hills. The ECM GFS 500 mean still shows the unsettled weather contiuning. Can't remember now when that chart actually last showed a change lol.

[carinthian]

Hi,

 Here is the latest thoughts from over here. The thermal gradient seems to have now peaked over the Christmas Period, rainfall continues as a problem for the UK for the next 7 days rather than wind. The first weekend in the New Year will see a significant pool of cold air leave Canada pushing Eastwards into the North Atlantic with the potential for intense development of a Mid -Atlantic low pressure system. We think this particular system will be the catalyst for the change we have been expecting in Europe as the colder air north of the polar front makes more influence in the change of weather pattern. Increasing interest that this storm will slow and move southwest of the British Isles. 

 C

Edited December 28, 2013 by carinthian

[BLAST FROM THE PAST]

This period in New Year is going to be a nightmare to forecast and also will usher in a very 'impactual' weather period.  Talk of no cold or snow for north and hills only.......this will be an interesting run for Wales and SW 

 

 

BFTP

[Tim Bland]

It really has been a slow start to winter in the northern hemisphere. Snow is sparse in the Scottish highlands compared to the recent few winters. Norway, Southern Sweden and Denmark is pretty snowless. Moscow is 6c with little snow left!

Models are still pointing towards a spell of cool zonal weather. Could improve things for the ski resorts but for 90% of the population there is still no widespread cold and snow on offer

[Summer Sun]

A couple of tweets from Ian Fergusson on how the met office see the potential cold spell

 

Looking like a cooling trend into Jan but only "rather cold category" suggest UKMO, so fairly standard fare as it stands re temperatures...

 

Continental Europe milder than average; plus warmer sea temps than normal to NW: these factors should help tone any cold weather from N or E

 

https://twitter.com/fergieweather

Edited December 28, 2013 by Summer Sun

[Frosty.]

Increasingly cold and remaining very unsettled appears to be the trend locking in with the jet being forced further south and eventually height rises to the n / ne with a much more southerly tracking jet and slider lows potential in the mid-longer range, in the meantime, very disturbed with further stormy weather separated by brief quieter interludes with a risk of frosts, and with continued cold incursions with wintry showers at times.

Edited December 28, 2013 by Frosty.