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Winter Model Discussion 18Z 19/1/13 onwards.


phil nw.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

For the north east maybe, that chart does not show any more snow over the bulk of the country as what is does at +0z

Actually, many areas that were 5-10cms at T0 are up to 20-30 cm by T48, quite significant IMO

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Posted
  • Location: Poole, BH14
  • Location: Poole, BH14

Every run by gfs has been delaying the return to mild with now even more snow risk. The models are very much all over the place and i wouldnt give much support to what it is saying beyond 5 days

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Posted
  • Location: Wakefield, West Yorkshire
  • Location: Wakefield, West Yorkshire

This morning we have a pretty good agreement that things are going to get milder by next weekend. The overnight MetOffice update says this too.

However for coldies thee is no need to be disheartened. There is an interesting week coming up and all the signs point to this milder/less cold incursion being temporary.

We have of course seen GP's thoughts re Feb, and the long term MetOffice update indicates the same.

So for me, well I'm already looking forward to model watching for Round 2 into Feb.

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Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire

pretty poor 0z runs so far today,the profile to the North west has been absolutely awful since about November and SSW or not it continues to look awful.

Maybe my fixation with Greenland height rises is related to my location,its the best for the north west as we saw in 2009 and 2010,the trouble is i dont think ive seen a Greeny high since then.(oh hang on yes i have,i see great big whopping ones every june and july).

What a sodden climate we have here,not.

Understand your frustration because what has been notable this winter isn't just the lack of the elusive Greenland HP but how infrequently this has been suggested in the model output even in FI. As a consequence the NAO has often been neutral or positive. This is why from a synoptic point of view I feel sorry for GP because his winter forecast has been wrong.

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Posted
  • Location: Wythall, Worcestershire, 150m asl
  • Weather Preferences: Continental climate, snow winter, sunny summers
  • Location: Wythall, Worcestershire, 150m asl

This morning we have a pretty good agreement that things are going to get milder by next weekend. The overnight MetOffice update says this too.

However for coldies thee is no need to be disheartened. There is an interesting week coming up and all the signs point to this milder/less cold incursion being temporary.

We have of course seen GP's thoughts re Feb, and the long term MetOffice update indicates the same.

So for me, well I'm already looking forward to model watching for Round 2 into Feb.

Hope you're right Paul re feb, but for me unless we get sustained blocking towards Greenland any cold spells will be short at best and as we don't seem to know why the nao refuses to go negative, I'm not sure we can put high confidence in any cold forecasts.

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

pretty poor 0z runs so far today,the profile to the North west has been absolutely awful since about November and SSW or not it continues to look awful.

Maybe my fixation with Greenland height rises is related to my location,its the best for the north west as we saw in 2009 and 2010,the trouble is i dont think ive seen a Greeny high since then.(oh hang on yes i have,i see great big whopping ones every june and july).

What a sodden climate we have here,not.

of course most of us have no idea what your location is

please drop your location into your avatar?

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Posted
  • Location: Kilmersdon Radstock Somerset
  • Weather Preferences: None Really but a snow lover deep down
  • Location: Kilmersdon Radstock Somerset

Good morning folks. The third day of lying snow here with no thaw at all as yet. Will it stay intact for much longer. Here is the regular look at the 00z outputs from GFS, UKMO, GEM and ECM for today Sunday January 20th 2013 to find out.

All models show another 4-5 days of unsettled and cold conditions with rain, sleet and snow at times as the cold pool of air continues to circulate the UK with Low pressure areas and stalling fronts slipping SE over the South of the UK and down into Europe. Widespread night frosts will persist until the end of the week.

GFS then brings a change to milder weather by the weekend, first in the South and West and slowly on to more Northern and Eastern areas as the weak and blocking High out to the NE collapses SE. A thaw would set in and snow would turn to readily in most places as winds turn SW and become strong to gale force later next weekend as a powerful depressions sweeps across close to Northern Scotland. A rather cold and squally showery West airflow follows with wintry showers and sunny intervals with some further snowfall possible on Northern and Western hills. This weather type persists for several days as the parent Low slips SE, filling as it does maintaining a chilly and showery theme. Then further Low pressure moves in from the West with rain followed by showers once more wintry on Northern hills to close out the run.

The GFS Ensembles show another rather cold week to come with snow at times before the general consensus between the members this morning is for the Atlantic to win back supremacy with Low pressure spreading rain at times across the UK in more traditional January fayre with normal uppers. There is though quite a lot of spread later in the run with a few members wanting to keep rather cold conditions going. The operational was on the milder side of the pack at times but not by much overall.

The Jet Stream forecast supports the evolution above with the flow crossing the Atlantic and Europe well South of the UK currently rising to our latitude by the end of the week with a more sine wave like motion by then indicating more mobility West to East of the pattern.

UKMO shows the Arctic ridge finally giving way on Friday and collapses the cold block SE at the start of next weekend allowing milder SW winds to take hold with a thaw and rain at times likely over next weekend although the Jet Stream remains well South in the Atlantic.

GEM is more dogmatic than the other models this morning maintaining the cold and unsettled weather right out to the end of the run, maintaining the cold block to the NE longer and eventually allowing a pressure rise over Greenland late in the run although milder air will infiltrate Southern areas later the pattern would probably evolve in allowing cold weather back to all with time probably in terms of a Northerly.

ECM finally shows a slow ingress of milder air across the UK next weekend but progress is shown to be slow as the Low pressure disruption continues but over the British Isles rather than to the SW which allows at least Southern and Western areas to become milder and wetter while Northern and Eastern areas hold on to the colder and potentially wintry conditions longer.

In Summary this morning all models support a sneaking in of the Atlantic next weekend after another cold week this week with further frost, ice and snow at times. Sneaking though is a good word as it's progress is slow and messy with a certain amount of disruption still taking place to depressions as they reach the UK as per GEM and ECM to a degree. This means in real terms that rain and milder air will bring about a thaw though conditions in the North and East will be slower to give way to this weather type. How long such a milder interlude will be with ECM dropping last nights quick return to cold. However, there is a long way to go between now and the weekend in UK Winter cold blocking patterns so don't be surprised if there aren't more swings back towards cold shown again through the week as models struggle on how to deal with the detail within the synoptics.

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Posted
  • Location: Catchgate, Durham,705ft asl
  • Location: Catchgate, Durham,705ft asl

Before making a judgement on next weekend,bare in mind what the ECM and GFS were

predicting for today this time last weekend...

ecm.. gfs..

today's chart..

Edited by Cloud 10
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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL

Without this normal 'winter fare' cold spell (temp dropped below zero for the first time last night by the way), we would still be desperately waiting for building of Greenland heights to be seen in the models.

So far there has been no building of high pressure towards Greenland. Time is fast running out. Hopefully next winter will be forecast as mild because everytime its forecast as cold with the long range models showing it, it just dosent materialise.

It was -13C at RAF Marham this week.

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

Before making a judgement on next weekend,bare in mind what the ECM and GFS were

predicting for today this time last weekend...

ecm.. gfs..

Yes C 10, models are still struggling past +92hr as per the last week or so. A very wintry 7 days to come, with temps barely getting above freezing in most parts of the UK, severe frost's at night and more battleground snowfalls to come as weather systems rattle in off the Atlantic into the cold air.

Edited by Polar Maritime
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Posted
  • Location: st albans
  • Location: st albans

Before making a judgement on next weekend,bare in mind what the ECM and GFS were

predicting for today this time last weekend...

ecm.. gfs..

today's chart..

had a look at that yesterday. ecm was having its 3 run wobble and gfs was ............. well gfs ! ukmo stood out like a beacon from T144 and never varied form the undercutting. maybe gem can be our ukmo this week !!

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

had a look at that yesterday. ecm was having its 3 run wobble and gfs was ............. well gfs ! ukmo stood out like a beacon from T144 and never varied form the undercutting. maybe gem can be our ukmo this week !!

Looking at the GEM I wouldn't grumble ! Fantastic end to the run..

gem-0-228.png?00

Edited by Polar Maritime
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Posted
  • Location: st albans
  • Location: st albans

Without this normal 'winter fare' cold spell (temp dropped below zero for the first time last night by the way), we would still be desperately waiting for building of Greenland heights to be seen in the models.

So far there has been no building of high pressure towards Greenland. Time is fast running out. Hopefully next winter will be forecast as mild because everytime its forecast as cold with the long range models showing it, it just dosent materialise.

have you moved to the uk from canada ? this winter, based on the past few decades is pretty reasonable re cold and snow thus far. not near the top but a long way from the bottom. we still have 5 to 6 weeks before march so methinks your post is a tad early.

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Posted
  • Location: Reigate, Surrey
  • Location: Reigate, Surrey

Yes that 120hrs is a very cold chart with that continental flow. The UKMO haven't just modified their raw output they've ditched it completely.

But we're not out of the woods yet as for some reason that raw output came out with a very progressive run and we need that to backtrack tomorrow morning.

Overall still alot of uncertainty as to when the cold spell will come to an end.

Assuming there's snow cover on the ground Nick, we might be looking at an extreme overnight frost if the t120 chart is anywhere close to the mark.

GEM is interesting this morning and shows where we might head if more energy goes south around t96 than the other models currently show. Normally you'd ignore one model showing that - but the tendency over the last week or so has been for the models to switch once we get to around t72 and disrupt the incoming lows.

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Posted
  • Location: South Essex
  • Location: South Essex

Usually I look out to FI at say 192 hours for rough trends, but as per the last couple of weeks there are none today.

Looking through all the runs and ensembles this morning at 120 and 144 hours there are still wild differences. At day five most charts I've looked at keep us very cold but by day six its a more mixed picture. Where milder air comes into the mix the transitions being proposed seem much to quick to me.

Just from experience and gut feeling I'm going for GEM this morning as being the nearest in the medium term. I think the mid Atlantic lows are being overdone and the current situation is just screaming for stronger height rises over scandi.

Breakdown still five days away at earliest which is where its been for the last week or so.

Jason

Edited by Jason M
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Posted
  • Location: hertfordshire
  • Location: hertfordshire

Hope you're right Paul re feb, but for me unless we get sustained blocking towards Greenland any cold spells will be short at best and as we don't seem to know why the nao refuses to go negative, I'm not sure we can put high confidence in any cold forecasts.

This cold spell has been here for seven days now with much of England struggling to get above freezing since last

Sunday and we still have at least another four to five days of daytime temps struggling to reach freezing and

further snow threats accompanied by severe overnight frosts. A very significant cold spell in my book and just as

potent as the January cold spell of 2010 for this location if not longer.

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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

Just a word of caution to those hanging on to promise of a cold February delivered by SSW. The early part of February 2009 bought a cold snowy spell and at that time there was a similar promise that the second half of February would deliver an even colder spell. it never materialised and instead the month ended up quite springlike.

If this does breakdown friday as the models suggest, it's be disappointing but it'll be another pleasing winter overall, whatever further cold spells might come our way. But i do agree that the five day breakdown seems to be a recurring theme of late. The GFS bought it in first. Now others are following as they so often do. So perhaps instead of just the GFS being wrong, they all are now!

I'd wait for the CMA to deliver its verdict! :)

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Top posts by cloud 10 and Polar Maritime, the breakdown is still in FI and however the breakdown is currently modelled will not be how it happens if it happens, it's a very complex picture, the gfs in particular has been forced to delay it and it could easily just keep being pushed back and back. The current very cold, icy and snowy spell will continue within the reliable timeframe, FI is T+96, maybe even slightly less but we have a deep cold pool over the uk and it will take some shifting, in the process it could be very snowy.cold.gifcold.gif

In the meantime, heavy snow in the southeast today pushing north and mon/tues could be very snowy across northeastern britain with easterly gales whipping the snow into deep drifts, snow showers also becoming widespread across the northeast and these will merge with the persistent snow spreading north. also some snow for other areas in the coming days.

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Posted
  • Location: Bracknell, Berkshire
  • Location: Bracknell, Berkshire

Before making a judgement on next weekend,bare in mind what the ECM and GFS were

predicting for today this time last weekend...

ecm.. gfs..

today's chart..

Couldn't have seen a more brilliant post this morning.

Its really surprising to see the models be that off at a timescale of a week. I often wonder of they feed in norms in to the background modelling. Probably one for the technical discussion, but do they use past trends to support model progress and does this induce model bias towards a long term mean when synoptics are say..a standard deviation away from what would be average at t0. We constantly see the GFS over egging lows and gradually trying to return us to mild before backtracking and I wonder if this influences models on a macroscale basis.

Incidentally, monday/tuesday looks like a forecasing nightmare

13012118_2000.gif

Sorts of a southerly flow due to the low west of ireland and a NE or so flow from the shortwave/low to the SE. Wouldnt want to be the one calling that one, especially given the marginality.

Edit: The last sentence going on the GFS of course

Edited by john w
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Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire

06Z GFS swinging towards the Euros.

The GFS really has been too eager in sending energy E as our ridge of HP puts up more of a fight than the GFS expected.

http://www.wetterzentrale.de/pics/Rtavn961.png

A very poor period for the GFS this has been.

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Posted
  • Location: Wythall, Worcestershire, 150m asl
  • Weather Preferences: Continental climate, snow winter, sunny summers
  • Location: Wythall, Worcestershire, 150m asl

This cold spell has been here for seven days now with much of England struggling to get above freezing since last

Sunday and we still have at least another four to five days of daytime temps struggling to reach freezing and

further snow threats accompanied by severe overnight frosts. A very significant cold spell in my book and just as

potent as the January cold spell of 2010 for this location if not longer.

Indeed cooling it has been impressive and personally I've done very well, 15cms on the ground and snowing again right now, however for me we've been a bit lucky given the lack of high level blocking, that its lasted as long as it has. Not sure we can hope to get as lucky again without more sustained blocking around Greenland in place. For me I'd just love to know the root cause of this lack of blocking, given all the favourable background signals- ssw, mjo etc.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Still looks a bit nippy on fridaylaugh.pngcold.gif

post-4783-0-77905700-1358676596_thumb.pn

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

The models just can't seem to make up their mind as to how much energy heads se from Greenland, and whether this clears se into France.

Its evident though that to extend the cold we must have the shortwave clearing cleanly into France.

Far too much chopping and changing between runs to have much confidence in any of the outputs, the ECM ensembles at 144hrs looks solidly behind a change to milder conditions but whilst you keep getting these early changes I wouldn't rule out the cold hanging on for a while longer.

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Posted
  • Location: South Essex
  • Location: South Essex

The models just can't seem to make up their mind as to how much energy heads se from Greenland, and whether this clears se into France.

Its evident though that to extend the cold we must have the shortwave clearing cleanly into France.

Far too much chopping and changing between runs to have much confidence in any of the outputs, the ECM ensembles at 144hrs looks solidly behind a change to milder conditions but whilst you keep getting these early changes I wouldn't rule out the cold hanging on for a while longer.

The models keep overplaying the Atlantic. They handle things up to about 100 hours out then bang, the Atlantic explodes into life for no apparent reason. I still think the Atlantic low is being modelled too far west and heights over scandi are being underplayed.

Jason

Edited by Jason M
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