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

[TSNWK]

ECM looks different to me at 144 and 168. Is that 970 low at 144 a sign of some trough disruption and 168 looks pretty cold to me on the ECM.

Edited December 21, 2013 by TSNWK

[Mucka]

ECM looks different to me at 144 and 168. Is that 970 low at 144 a sign of some trough disruption and 168 looks pretty cold to me on the ECM.

 

It would be very chilly were it to verify and snow could fall just about anywhere but it will probably be pretty much on its own on the London ensembles temp wise for 168h.

Should provide plenty of discussion this morning though.

[TSNWK]

It would be very chilly were it to verify and snow could fall just about anywhere but it will probably be pretty much on its own on the London ensembles temp wise for 168h.Should provide plenty of discussion this morning though.

Thanks. Yep if the ECM verified we could have a Wednesday to Saturday cold spell / snap creeping up on us, certainly the north of England and Scotland might expect something a little seasonal from the sky, in my part of the world I expect a colder version of rain, but it does keep the interest going.I quiet liked this mornings ECM, after the cheeky cold snap mentioned above we have a couple of less cold days, however the end of the run still offers interest in my eyes as the next blob of the vortex thrown at us does appear to be disrupting and heading south east.. Well thats may take, as you say it should at the very least invite some debate this morning.Cheers Edited December 21, 2013 by TSNWK

[Cecil Hogmanay Melchett]

I'm not sure about that assessment TBH

The output doesn't go out to the second week of Jan and there are plenty of signs of attempted Northern blocking in the output IMO.though whether it comes to fruition and is favourable for bringing cold to the UK is another matter.

Still, there is nothing to say there is only one way to interpret the output.and GEM is very poor this morning.. 

 

GFS 00z ensembles central England

http://www.meteociel.fr/cartes_obs/gens_display.php?x=256&y=98&run=0&runpara=0&type=3&ext=1.

Yes my bad mucka,but gfs 0z run would certainly offer nothign in the way of blocking if it went to the 2nd week.

ECM looks better with the azores high further south than the others in the reliable.

Hopefully a chance of some wintery weather over chrsitmas.

[IDO]

The GFS op and ens mean are more of the same:

 

 

A split vortex with the Canadian vortex still giving a westerly flow. The push north of the pattern remains in the current mean but its an arduous process. There is no sign of prolonged cold and snow to the north or high ground is a possibility but the op has only small windows of opportunity for this. 2m temps are slightly below average at the end of FI but nothing to raise expectancies.

 

The ECM is an outlier compared to the GEFS for next week. Both have a low at T96 spinning off the Canadian vortex:

 

ECM:     GFS: 

 

The ECM splits the energy and some goes S/SE. The UK therefore misses out on that LP system and gives the trough time to dig south for a few days:

 

 

GFS op pushes and develops that low towards the UK, flattens the pattern and speeds up the eastward push of the trough: 

 

We will see if ECM has this SW development correct. A couple of GEFS do also show this but low confidence in this at the moment.

Edited December 21, 2013 by i'm dreaming of...

[bluearmy]

ecm, having set the tone for the development of the depression next week - now all the models are in agreement on a very developed deepening system, it jumps ship this morning with a weaker system that therefore doesn't phase with the parent trough and drifts across the UK, keeping the country under the trough ( with likely snowfall n UK). This should be an outlier solution but given that its fairly early in the run, we should hang around for the 12z op before completely dismissing it.

overall, not much has changed - plus pretty good x model agreement now on a developing arctic high between Siberia and the pole. That may well be useful going forward for coldies.

[Lincs Observation]

Morning all

 

This appears to be the MetO possible solution in the near timeframe.

 

[Gibby]

Good morning folks. Today is the shortest day and from today o the hours of daylight become slowly longer. So with that thought in mind here is my look at the NWP output based on the midnight outputs for today Saturday December 21st 2013.

 

All models continue to show very volatile conditions across the UK up to and over the Christmas period. A showers WSW flow shown today will be exacipated by an active squally trough sweeping East tonight following the final clearance of rain from the SE earlier in the day. Once passed temperatures will fall markedly as a colder westerly flow is shown to take hold with scattered showers and sunny spells tomorrow with most of the showers near Western coasts with some Eastern parts becoming dry. On Monday another powerful storm system close to the NW is shown to spread severe gales and loads of rain across the UK from the SW and it will become mild again especially in the South. By Christmas Eve this weather is shown to be replaced by colder and more showery conditions in the North and West filtering down into the SE later. Christmas Day then looks to be a colder, less windy and potentially showery day with some sheltered areas away from prevailing West winds perhaps seeing a dry day while areas in the West see showers, wintry on hills. Boxing Day looks like starting dry and cold for many away from Western areas with a frost and light winds for a time. Later in the day things go quickly downhill as the next Atlantic storm system approaches the UK from the West.

 

GFS then shows the run up to the New Year as remaining very unsettled and potentially stormy as further Low pressure brings rain and showers in off the Atlantic repeated over the New Year before things finally look like becoming less stormy and quieter especially across the South as the Jet stream moves North and takes the worst of the depression further North to affect the north far worse than the South by the end of the run.

 

UKMO closes it's run on the 27th with a new deep Low pressure out to the NW having spread mild and strong SW winds back across the UK with gales and heavy rain likely for all at times with severe gales in places.

 

GEM today also shows a continuing very unsettled period lasting up to and including the New Year as successive depressions deliver wind and rain followed by showers for all. It too though shows pressure rising over Europe which may steer some of the heavy rain away from the South and more towards the NW as we enter 2014.

 

NAVGEM closes it's run with a powerful storm system centred between Scotland and Iceland next weekend with strong to gale WSW winds and rain followed by squally showers affecting all parts next weekend with wintry showers again over the hills.

 

ECM shows the post Christmas storm much further South this morning and less deep crossing the Centre of the UK. Nevertheless it would provide Southern regions with a potent gale and spell of heavy rain while the North sees colder and more showery weather before all areas remain changeable thereafter with the New Year period looking every bit as unsettled as a new deepening Low rattles into the UK from the Atlantic on New Years Eve.

 

The GFS Ensembles remain an unsettled bunch maintaining total Atlantic domination throughout on sometimes strong Westerly winds. As a result little if any sign of significantly cold or indeed mild weather shown with plenty of rainfall over the period from most members.

 

The Jet Stream shows the flow across the Atlantic and on collision force with the Uk throughout the next week. It troughs South of the UK over Christmas briefly before the next storm system pulls it North again post Christmas. In the neverland it does show signs still of wanting to ridge North around an Atlantic High but it looks like it could be flattened quite quickly again as pressure is put on it by further cyclonicity exiting the States.

 

In Summary there is absolutely no sign of any change in the weather pattern over the next 10 days with further gales and heavy rain at times for all. Hopefully any damaging weather looks restricted to Monday and Christmas Eve now with a quieter but still unsettled period over Christmas itself especially across the South. there is the chance of a white christmas for a few as cold uppers could bring some of the colder air to the surface in heavy showers, most likely in the West and North. As we exit Christmas and into the New Year there is little difference with yet another storm system up to the North dictating the wet pattern for the period. The only nugget of hope for drier weather could come from a rise of pressure to the SW, South or SE as we move into the New Year shunting the deepest part of depressions further NW and restricting the severity of wind and rain to these areas. However, I appreciate this is not what cold weather fans want to here as if it verified it would keep cold weather well away from the UK well out into January at least.

[Frosty.]

There appears to be a gap in the most severe weather (wind wise) between the 24th-26th dec away from the northern third of the uk with rather colder air becoming established across the uk bringing a more wintry flavour to our weather with icy patches overnight and wintry showers of hail, sleet and snow, even some longer spells of wintry ppn...so, some of us could wake up to a white christmas but even for those who don't, it won't be mild, thankfully we are not in the midst of a mild zonal spell, mild weather is at a premium. The Gfs 00z looks generally very disturbed with regular bouts of heavy rain and severe gales interspersed with colder, showery spells and it's our good fortune that one of those colder, showery spells coincides with christmas this year, so it will feel seasonal at least. Looking beyond christmas, very turbulent again with more powerful atlantic systems but with cold incursions from the northwest possibly becoming more frequent. In the shorter term, christmas eve night could be snowy in places.

Edited December 21, 2013 by Frosty.

[shaky]

Well the drama is not over yet!!the ecm has come out with a lovely run this morning but where the heck has that deep low gone 120 hours?.if the ecm has this right then expect a big snowfall somewhere along the cold/warm boundary.and even before that with low thicknesses we could see snowfall anywhere. Hopefully ecm has got this right.

[Nick F]

A pool of cold polar maritime air surging east then northeast across the UK beneath the deep low NW of Britain on Tuesday, its origin over the Northern Territories of Canada. This cold rPm flow follows an active cold front surging east Monday Pm, which itself will bring a spell of widespread gales or severe gales.

 

Forecast dew points falling below 0c increasingly widely on Xmas Eve, and forecast 850-1000mb thicknesses falling sufficiently for wintry showers arriving across the west in the strong southwest flow to fall as snow across northern and western areas - though settling maybe reserved for higher gound initially. Severe Gales (70-80mph possible) across the north close to the deep low to the NW would likely bring blizzard conditions in any snow showers.

 

Xmas Day itself looking to be a cold day, with temps in low to mid single figures in the rPm southwesterly flow, cold enough still for some wintriness in the showers likely across the west - though the cold air arriving Xmas Eve looks to be mixed out by then, but for most areas away from the far west it's looking dry, sunny, cold but rather windy at first, though the southwesterly wind easing through the day.

 

Further ahead, not a great deal of change showing until the end of the year at least, with a very mobile and disturbed Atlantic - bringing a risk of deepening secondary lows across the UK bringing more wind and rain, with alternating mild and cold maritime airmasses - which will allow some marginal snow to fall in places - more especially in the north. As Ba said, prominent arctic high showing later in the GFS and ECM runs, which may expand towards Barents and Greenland to help perhaps break-up the vortex as we head into the New Year - but a long shot for now.

[stratty]

There appears to be a gap in the most severe weather (wind wise) between the 24th-26th dec away from the northern third of the uk with rather colder air becoming established across the uk bringing a more wintry flavour to our weather with icy patches overnight and wintry showers of hail, sleet and snow, even some longer spells of wintry ppn...so, some of us could wake up to a white christmas but even for those who don't, it won't be mild, thankfully we are not in the midst of a mild zonal spell, mild weather is at a premium. The Gfs 00z looks generally very disturbed with regular bouts of heavy rain and severe gales interspersed with colder, showery spells and it's our good fortune that one of those colder, showery spells coincides with christmas this year, so it will feel seasonal at least. Looking beyond christmas, very turbulent again with more powerful atlantic systems but with cold incursions from the northwest possibly becoming more frequent. In the shorter term, christmas eve night could be snowy in places.

...................do you pen for the Daily Express at this time of year Frosty?

 

They should sign you up! 

[Frosty.]

...................do you pen for the Daily Express at this time of year Frosty?

 

They should sign you up! 

no, it's what the gfs 00z op run shows, the run I was describing.

[Summer Sun]

UKMO has Tuesday's low at 940mb

 

 

Respite for most Wednesday and Thursday

 

 

Next low incoming for the Friday

 

 

Tuesday's low on ECM looks to be around 930mb

 

 

t144 between UKMO and ECM is miles apart

 

[Timmytour]

Going by the 0z GFS the friday after Christmas, a working day for many of us, could provide some quite tricky commuting conditions with that rapidly deepening depression on Boxing Days develops and reaches the British Isles

[snowice]

UKMO has Tuesday's low at 940mb

 

 

Respite for most Wednesday and Thursday

 

 

Next low incoming for the Friday

 

 

Tuesday's low on ECM looks to be around 930mb

 

 

t144 between UKMO and ECM is miles apart

 

 There is alot of cold air being sucked down from the artic on  the 24th ,i feel there is a chance of a white christmass for many in the north and west the placement of the low is not a done deal yet!tonights model runs should hopefully pin it down|

[carinthian]

Some encouraging signs now showing as we approach The New Year period with the upper trough making some in roads into the European High pressure . The rise of pressure over the Eastern Arctic moving towards the PV and hopefully making some changes  and easing the express zonal flow towards the UK. Some ridging in the Atlantic would seem likely with NW/SE axis of the upper flow.

So for longer term cold lovers some reward on the cards but as always we will need to see this development with-in 7 day time scale holding firm.

 C

[Summer Sun]

UKMO euro 4's take on the snow tomorrow

 

 

[bluearmy]

Some encouraging signs now showing as we approach The New Year period with the upper trough making some in roads into the European High pressure . The rise of pressure over the Eastern Arctic moving towards the PV and hopefully making some changes  and easing the express zonal flow towards the UK. Some ridging in the Atlantic would seem likely with NW/SE axis of the upper flow.So for longer term cold lovers some reward on the cards but as always we will need to see this development with-in 7 day time scale holding firm. C

Except the extended ECM ens continue to show weakly positive high euro anomolys and naefs similar. infant the 00z has built a reasonable one over the Low Countries/w Germany. I'd like to be positive about the first half of jan from a cold perspective but nothing to support that currently. Only caveat is that we see a fair amount of high latt high anomolys and our build of heights near us could easily be sucked up to our ne or retrogress west if the pattern dictates.

[shaky]

Would you believe it!!!!the gfs 06z has joined the ecm at 120 hours and there is no deep low pressure in the atlantic!!cant believe no one has commented yet!!this place is dead out.

Edit:it does go on to develop the deep low but is not as deep as the 00z around the 120 hour timeframe so in that regard very similar to ecm.see what happens this evening.

Edited December 21, 2013 by shaky

[dec10snow]

Does anyone have a link for the euro4 model?? Thanks!

[bluearmy]

Would you believe it!!!!the gfs 06z has joined the ecm at 120 hours and there is no deep low pressure in the atlantic!!cant believe no one has commented yet!!this place is dead out.Edit:it does go on to develop the deep low but is not as deep as the 00z around the 120 hour timeframe so in that regard very similar to ecm.see what happens this evening.

Looking around the 00z's, there is a fair spread of solutions on this little fella. some models develop it late, some early and ECM hardly at all. Might have to wait till tomorrow to get the fial consensus.

[IDO]

Except the extended ECM ens continue to show weakly positive high euro anomolys and naefs similar. infant the 00z has built a reasonable one over the Low Countries/w Germany. I'd like to be positive about the first half of jan from a cold perspective but nothing to support that currently. Only caveat is that we see a fair amount of high latt high anomolys and our build of heights near us could easily be sucked up to our ne or retrogress west if the pattern dictates.

 

Yes, not much positive in the LR models. The JMA for week 3-4: 

 

Looks like height anomalies in Russia, N.Pacific and the AH. The main part of the vortex still in situ over Canada with a flat westerly flow and the jet pretty much targeting the UK, with us at the end of the zonal train. Chances of a repeating troughing to our S/SE if the phasing of the stream of lows coming from our west allows, but temporary cool/cold rather than any prolonged spell of cold.

 

Not sure heights over the pole will help much even in the long term with the vortex where it is charted. Certainly a kick from the strat is needed to mix up the long wave pattern, otherwise January could be disappointing for a cold pattern, other than just short lived PM shots for the north.

Edited December 21, 2013 by i'm dreaming of...

[TonyH]

...................do you pen for the Daily Express at this time of year Frosty?

 

They should sign you up! 

It does tend to hype up potential wintriness, not seeing anything other than transient hill sleet and snow Christmas Eve, perhaps the odd localised stuff lower down, but certainly not settling below 200m, and it would require a long drive or strenuous hike up a big hill to experience lying snow. Uppers -2c or -3c over the Midlands would require a very special set of ingredients to produce snow here on the 24th/ 25th for example.

Edited December 21, 2013 by TonyH

[Nick L]

Does anyone have a link for the euro4 model?? Thanks!

 

Here you go:

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=euro4&MODELLTYP=1&VAR=prec&HH=3&BASE=-&WMO=&ZOOM=0