Model Output Discussion - 23rd Jan - 12z onwards

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS.

THE CURRENT GENERAL SITUATION A cold and windy NW flow will continue across the UK over the next 24-48hrs veering slowly more Northerly tomorrow with showery troughs of Low pressure moving SE across the UK at times.

MODELS-2 WEEK HEADLINE Remaining cold with some snow showers especially near northern coasts. Becoming dry and possibly less cold later.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Forecast shows the deep trough in the flow across Europe currently remaining for another week or so before signs of the trough lifting out to a UK based Jet flow West to East flow is shown later in the period.

GFS OPERATIONAL The GFS operational today shows cold weather likely to continue across the UK for the reliable future. With winds mostly from the North coastal areas will experience wintry showers and as various disturbances  run SE close to or over the UK more organized bands of precipitation could give more widespread and significant snowfall especially in the West and SW early next week. Later in the period High pressure ridges across the UK slowly cutting off the cold feed with frost and sunny days replacing any snow showers. By the far end of the run milder SW winds look like pushing the ridge slowly away to the South.

THE GFS CONTROL  The GFS control run differs in as much as it develops a UK based High pressure area across Britain by the second week lasting some considerable time with dry and sunny days but very cold and frosty nights for all.

THE GFS CLUSTERS The GFS Clusters show a 70% chance of the UK under the influence of High pressure lying close by either over or to the South of the UK. The majority holds the High closest to Southern Britain with a greater chance of milder Atlantic SW'lies affecting the North by Day 15.

UKMO UKMO this morning looks cold throughout with small disturbances running South to the West of the UK early next week with the risk of more prolonged rain or snowfall for a time while the snow shower theme continues elsewhere. By the end of the run High pressure inching in just to the West of the UK looks like sustaining cold weather with some severe night time frosts where snow is lying but eliminating the risk of further snow showers.

THE FAX CHARTS The Fax Charts illustrate the complexity of the situation in the Northerly winds with further disturbances in the flow running South and SE over or close to the UK enhancing the risk of more widespread rain or snow at times in the otherwise cold and showery feed.

GEM GEM today shows another week of this cold and wintry pattern of weather with further wintry showers in places especially near exposed West, north and East coasts and also with the risk of more widespread wintry precipitation at times as disturbances run South in the flow. Then a ridge topples SE across the UK late next week with milder SW winds then extending to all areas by the end of the period.

NAVGEM NAVGEM today keeps the cold going over the UK through next week veering winds towards the NE as a ridge of High pressure lies NE to SW across Scotland by next weekend maintaining cold and frosty weather in the North and keeping a breeze from the NE over the South with wintry showers near Eastern coasts.

ECM ECM this morning also shows another week of cold weather across the UK before a moderation in conditions under Atlantic WNW'lies develop by the end of the weekend. Last to see this change will be the SE where cold weather and a NE flow for a time may maintain a risk of wintry showers before the High pressure takes over and backs winds off to the WNW.

ECM 10 DAY MEAN The 10 Day Mean this morning maintains a trough across Europe with an Atlantic anticyclone to the SW North of the Azores. This pattern is no doubt made up of varying scenarios mostly revolving around the likelihood of winds maintained from a North or NW source over the UK for some considerable time yet.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend is firming up somewhat in a moderation in the cold conditions across the UK later next week as High pressure moves over bringing a different type of weather with sunny days and frosty night more likely than sleet and snow. The trend for the High to slip away South much later has gained some momentum this morning from ensemble output.

MY THOUGHTS The UK lies under two regimes at the moment. Some especially in the North and Central regions lie under a blanket of snow while many others have none and in these areas the cold spell will be most likely viewed currently as a non event. However, irrespective of snowfall or not the cold NW wind is and will continue to be felt by all with significant windchill for all and it's this that remains the most impactive feature of this spell. Of course those enthusiasts on here will be looking for snow and the risk continues for there to be further snowfall at times, probably in similar areas to those that have experienced it already. However, early next week offers a chance for the SW and West to see a risk of snowfall although this morning's output seem to hold things a little too far West for that to be guaranteed. Then as we move deeper into next week there is strong support for the Northerly flow to loosen it's grip in the wake of an Atlantic High pressure which although maintaining the cold would eliminate snow showers and give rise to sharp night frosts especially over snowfields of the North. Then further out still there is gathering momentum that this High will then slip South and bring in less cold Atlantic air around a relocated High to the SW of the UK in Week 2. It is still far too early to call that evolution as likely to be correct and it maybe that further prolonging of the cold spell crops up in the coming days. The one disappointment for cold lovers though is the lack of desire to rise pressure significantly to the North and NE later in the period which unless happens will be more likely to end up guaranteeing the end of the cold spell from next weekend as the Atlantic Westerlies regain a foothold.

Issued at 08:00 Friday January 30th 2015

Edited January 30, 2015 by Gibby

[Jason M]

The trend of the last 36 hours seems to be a gradual toning down of the low heights to our NW. Okay, the opp don't show screaming sub zero easterly winds, but we are now in the game. The GFS opp was one of the worst options at 192. Most GEFS had an easterly drag across the South. Gem ens also show this.

I'll take this mornings 00hrs suite over yesterday's.

The cold is probably a given for 8 days, it's now whether we can get a decent snow event. That one will be a harder question to answer.

[fromey]

This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

[Catacol]

Met office hinting at breakdown next weekend.

http://images.meteociel.fr/im/7859/ECH1-240_bki1.GIF

Output suggesting this possibility, yet when someone suggests it they often get shouted down...

If this were the other way round, not many would have a problem with people hunting for cold....

A little respect to others opinions and each other would be a good discussion I feel.

 

That's a 10 day ECM chart, not the MetO. If it comes to pass that way then you are right. However GFS for the same slot has a much more marked low pressure signal to the south

So all in all I'd say outlook uncertain. Hints of a breakdown are neither consistent nor clear.The only thing that IS clear is that energy is riding over the top of the atlantic and that makes this "longest lived toppler ever" [Chio] scenario a fascinating one. I dont recall ever seeing a situation quite like this - and with other signals (MJO and strat) suggesting that the medium may favour more blocking then I'm genuinely clueless as to what the patterns will look like by Feb 9.

[weather eater]

At the moment I would say we do have good consensus from the models and that being.

1. Colder conditions will persist for another 7 days, give or take

2. The high will topple and end up over or just to our west

3. getting  blocking in the right place for the type of easterly we want to see seems highly unlikely no matter how often the ensembles might point that way, This is not to say that during the week ahead there will not be an easterly component to our weather but nothing that involves HLB where we want it

However we should also keep it in mind that a week is an awful long time in synoptic evolution and things can swing very rapidly.

[Severe Siberian icy blast]

This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Well that sounds grim to be honest . Mid February and the jet running North of uk with high pressure to South , that's put an end to my fanthom easterly then . If that's really the case and winter whistles away again then considering all the potential since autumn this will be another rubbish winter with no high lat blocking for a second year on the trot

[Continental Climate]

This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Well not what many people would want to hear I'm afraid but sadly for many a very plausible outlook. Seeing that it is coming from a senior professional then i place a lot of credence in it!! 

[mountsbaysnow]

Well all in all as long as I get to see at least one snow day before then I would be a satisfied customer

Edited January 30, 2015 by mountsbaysnow

[Winter Cold]

Well that sounds grim to be honest . Mid February and the jet running North of uk with high pressure to South , that's put an end to my fanthom easterly then . If that's really the case and winter whistles away again then considering all the potential since autumn this will be another rubbish winter with no high lat blocking for a second year on the trot

 

Im shocked too at that signal. we dont know how strong it is though, as 'signs' doesnt sound very convincing. Hope it fades.

 

When we have fantastic posts on here from Tamara for example, giving a very convincing argument for a 'good' February through providing a very detailed report on background signals then this signal seems to go against everything. It sounded like everything was in our favour reading her brilliant posts.

 

Cold looks locked in until Friday anyway, plenty of -8 850s around from Sunday onwards and models do show features and kinks in the isobars so is not all doom and gloom

[mushymanrob]

easterly? what easterly?... placing too much hope on one unsupported run is a mugs game imho...
so yes, its cold, yes theres some snow around, but its going to be far from a decent dumping or big freeze for most of us. and after tuesday whilst it remains cold with hard overnight frosts (and fog i suspect where the breeze dies down) its a pretty normal cold spell.

for those of us (me! lol) who dont like february cold, the outlook this morning is good with strengthening agreement that the cold will fizzle out slowly over days 7 - 10 .

 

yep its currently fi.... and could of course change though i suspect its the timing thatll change more then the outcome. no easterly here.
 

Edited January 30, 2015 by Paul
Un-needed comments removed

[seaside 60]

This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Playing devils advocate, you could also go the way of my highlighted text.

[Woollymummy]

This would be really warm and springlike weather, am I right? compared to this coming week.....I am joking really, but am not sure if this is what is meant by the breakdown, surely it is just another version of cold and wintery? and is this too far in the future for it to be likely?

Edited January 30, 2015 by Woollymummy

[shotski]

Hang on a minute !! Wasn't GS5 and Mogreps showing a strong signal for a blocked pattern 10 days ago ? Very strong signal I seem to remember for mid feb. Goes to show that it's not always right.

[Stuie]

A breakdown in 7/8 days time is a bit of brave man FI scenario to call isn`t it?

 

Looking at the mean 0z ECM 850`s for Norwich they actually want to trend even lower until the 6th. That will do as a benchmark for now. 

 

[frosty ground]

easterly? what easterly?... placing too much hope on one unsupported run is a mugs game imho...

so yes, its cold, yes theres some snow around, but its going to be far from a decent dumping or big freeze for most of us. and after tuesday whilst it remains cold with hard overnight frosts (and fog i suspect where the breeze dies down) its a pretty normal cold spell.

for those of us (me! lol) who dont like february cold, the outlook this morning is good with strengthening agreement that the cold will fizzle out slowly over days 7 - 10 .

Rtavn2402.gif Recm2402.gif

 

814day.03.gif

yep its currently fi.... and could of course change though i suspect its the timing thatll change more then the outcome. no easterly here.

 

Have to agree I see no Easterly, I see maybe more Disruption to the Atlantic for a short while longer but I think the writting is on the walls that in 7-10 days time the Atlantic will roll in with High Pressure to the south as per the charts you have posted..... not the end of winter by any means but it will give those who want a bit of warmth something to cheer.

As for who called this spell correct..... Firstly lets wait until after its over Its easy to claim someone is right before the event, especially when the same cliam is made every day...... Like Shooting Fish in a barrel unfortunately no one has made a hit yet.

Edited January 30, 2015 by Paul
Edited quote

[Captain Shortwave]

A breakdown in 7/8 days time is a bit of brave man FI scenario to call isn`t it?

 

Looking at the mean 0z ECM 850`s for Norwich they actually want to trend even lower until the 6th. That will do as a benchmark for now. 

 

Indeed, still time for things to change in the week 2 range.

Speaking of complications from the east. The 06z GFS does offer a relatively brief east to north easterly during the later half of next week

The -8C isotherm gets across the whole of England and Wales with snow showers for eastern coasts. Even if the Azores high simply rebuilds into the UK after this, there is potential to eek something decent from this. It wouldn't take much to get some very cold air over the UK from the East and with low pressure over Europe, there is always the chance of something moving up from the continent.

So in all turning a little less cold and more westerly from next weekend looks most likely at the moment, but I still feel that even by Friday some places may still see some of the white stuff falling from the sky.

Edited January 30, 2015 by Captain shortwave

[frosty ground]

Hang on a minute !! Wasn't GS5 and Mogreps showing a strong signal for a blocked pattern 10 days ago ? Very strong signal I seem to remember for mid feb. Goes to show that it's not always right.

Yes but the blocking position was not mentioned, because it was unknown. 

[Continental Climate]

Could be a bit of a repeat pattern being attempted here i think http://www.wetterzentrale.de/pics/Rtavn1681.gif!!! It wont make it though as heights too low to our north!!

 

At 192 there is nowhere for the high to go im afraid it certainly cant go north http://www.wetterzentrale.de/pics/Rtavn1921.gif

 

We just cannot get rid of the limpet polar vortex to our north!! Despite all the good background signals it has been stuck there all season 

Edited January 30, 2015 by Continental Climate

[shotski]

Yes but the blocking position was not mentioned, because it was unknown.

Yes but I wouldn't call the Azures high ridging in a blocked pattern. Ian also mentioned strong zonality.

[frosty ground]

Could be a bit of a repeat pattern being attempted here i think http://www.wetterzentrale.de/pics/Rtavn1681.gif!!! It wont make it though as heights too low to our north!!

This is more likely than any sustained easterly..... Like the last two spells we will have a mild spell first before a Reload. 

[Alexis]

The high is moving much more favourably on the GFS 6z. Pressure over Iceland is 35mb higher than the 00z!

[warrenb]

There seems to be a pattern here. The 0z runs seem to try to flatten, whereas all other runs for the day seem to re-amplify the pattern.

[seaside 60]

Indeed, still time for things to change in the week 2 range.

Speaking of complications from the east. The 06z GFS does offer a relatively brief east to north easterly during the later half of next week

The -8C isotherm gets across the whole of England and Wales with snow showers for eastern coasts. Even if the Azores high simply rebuilds into the UK after this, there is potential to eek something decent from this. It wouldn't take much to get some very cold air over the UK from the East and with low pressure over Europe, there is always the chance of something moving up from the continent.

So in all turning a little less cold and more westerly from next weekend looks most likely at the moment, but I still feel that even by Friday some places may still see some of the white stuff falling from the sky.

On that chart it seems that the whole Atlantic is high pressure with 2 big cells.

Also you could say the Azores high is replaced with a low pressure of 1010.

[Alexis]

Doesn't get there in the end, but little consistency from run to run.

 

Unsurprising since we have cold round 2 to get through from Saturday.

[TSNWK]

There seems to be a pattern here. The 0z runs seem to try to flatten, whereas all other runs for the day seem to re-amplify the pattern.

I agree.. Why is this.. But even so if we compare today's 00z with yesterday's for the end of the week the cold spell has been extended.

Edited January 30, 2015 by TSNWK