Model output discussion - 1st December onwards

[BLAST FROM THE PAST]

For me the contrast across the country is the talking point, overnight we could see up to 20c difference between parts of Scotland and Cornwall.  Even by day we'll see 10c+ difference.  So charts being posted targeting super mild aren't telling the current story for all UK, lots more going on; yep I'm stuck in the grip mild mush but I'm really fascinated by the contrasts . 

This is feature worth keeping an eye on, look at that little bump near Wales....more heavy rain heading to the wrong place?

 

 

BFTP  

Edited December 12, 2015 by BLAST FROM THE PAST

[gottolovethisweather]

42 minutes ago, IDO said:

No shock the GFS op is an outlier, it is the only member in the GEFS offering snow for London:   

 

Big back track as expected from the UKMO on last night's 12z: 

The ECM op is a beauty of a run for anomalous warm uppers:

Shock, no D10 teaser from the ECM this morning, normal resumption tonight I am sure: 

ECM D10     CFS w3 & W4: 

The CFS w3 and W4 look like they will have a more UK zonal flow by early January so maybe less warm and maybe wetter in the south but no sign of any pattern change (a bit early). The main cluster from the GEFS for Christmas day is 50% for a westerly zonal flow with mild conditions for the south (much like how week 2 is looking):

       2m temps GEFS: 

The 2m temps for London remaining milder than average through to D16 with little sign of anything remotely cool let alone cold. 

The MJO remains in the mild phases (4-5) for a while so nothing there to suggest changes:  

See what January brings?

Nope, that's called wishing your life away, things might not look good for cold weather enthusiasts right now, granted. However, a pre-Christmas week switch around in fortunes is more likely than not, given past climatic trends around that date (more specifically Christmas period itself) and D6 or thereabouts is where FI currently resides anyhow.

Edited December 12, 2015 by gottolovethisweather

[Mair Snaw]

32 minutes ago, IDO said:

No shock the GFS op is an outlier, it is the only member in the GEFS offering snow for London:   

 

Big back track as expected from the UKMO on last night's 12z: 

The ECM op is a beauty of a run for anomalous warm uppers:

Shock, no D10 teaser from the ECM this morning, normal resumption tonight I am sure: 

ECM D10     CFS w3 & W4: 

The CFS w3 and W4 look like they will have a more UK zonal flow by early January so maybe less warm and maybe wetter in the south but no sign of any pattern change (a bit early). The main cluster from the GEFS for Christmas day is 50% for a westerly zonal flow with mild conditions for the south (much like how week 2 is looking):

       2m temps GEFS: 

The 2m temps for London remaining milder than average through to D16 with little sign of anything remotely cool let alone cold. 

The MJO remains in the mild phases (4-5) for a while so nothing there to suggest changes:  

See what January brings?

To me that 10 day ECM isnt that bad a chart....Euro Slug under pressure.. majority of Vortex over Siberia ( yes still a piece left Greenland area) and some good looking WAA heading poleward from the Alaskan side... thats what i can see anyway... i might be wrong tho... as still learning

[gottolovethisweather]

33 minutes ago, Paul said:

That's a single grid point in Cumbria though, with low minima as shown there, I'd assume it's a grid point on higher ground, so it's not necessarily overdoing the mins so to speak. It's just a forecast for a colder spot within Cumbria, and that's why the difference between it and the ensembles is exacerbated, as the same grid point on the ensembles is within a bigger grid (ie lower resolution), and will therefore have a lower average height. 

I think I sense a need for a tutorial coming on, as I admit I'm a little bit lost when it comes to such discussions as these.

[knocker]

The ecm run is also notable for some wet and windy weather and it's above average temps and a possibility of of severe gales in Scotland on the 18th, if it verifies of course but in this set up it will be surprising if we don't experience a couple of nasty storms.

 

Edited December 12, 2015 by knocker

[Captain Shortwave]

27 minutes ago, bigsnow said:

To me that 10 day ECM isnt that bad a chart....Euro Slug under pressure.. majority of Vortex over Siberia ( yes still a piece left Greenland area) and some good looking WAA heading poleward from the Alaskan side... thats what i can see anyway... i might be wrong tho... as still learning

To be honest the best analogue regarding that ECM day 10 chart is to refer to most of winter 2013/14 with the Ridge in the Pacific pushing deep low heights towards the north and north west of the UK producing a much stronger jet stream across the Atlantic. It does look like an increasingly zonal picture after a fairly dry week in the south baring this weekends rain.

ECM ens show this nicely

The Euro heights are still there but the increasing strength of the jet stream squashes this southwards introducing unsettled weather for near enough everyone. Temperatures dropping away a little bit in relation to what we could see at the end of this week, though a strong westerly pattern usually supports near to slightly above normal conditions.

GEFs suite similar though slower in the change to a more westerly pattern.

Edited December 12, 2015 by Captain Shortwave

[IDO]

29 minutes ago, gottolovethisweather said:

Nope, that's called wishing your life away, things might not look good for cold weather enthusiasts right now, granted. However, a pre-Christmas week switch around in fortunes is more likely than not, given past climatic trends around that date (more specifically Christmas period itself) and D6 or thereabouts is where FI currently resides anyhow.

All well and good saying weather can change! but it won't change just because it can, there has to be a reason. Maybe some meat on the bone as to why you think there will be a sudden change in the NH synoptics? We have one of the coldest strat PV for a while and it is still cooling. This will promote a positive AO and that means no sustained cold likely in our region. 

  GFS Mean verification: 

Not discounting a bit of a PM flow in the mobile zonal setup but I am sure the majority are looking for a sustained blocked pattern that will provide a longer lasting cold spell? At the moment none of the drivers of the weather have any lead to a colder setup.

As for D6 being FI, that is clearly wrong, yes for surface conditions, but not for long wave patterns. The GFS Mean is performing very well at D10, much better than it usually does, currently 0.638 (last week over 0.7 on average), and that suggests that FI is probably nearer D15 than D6. 

Edited December 12, 2015 by IDO

[kev238]

This December clearly has had overwhelming signals for a mild zonal flow which is coming to fruition

sometimes it is best to concede that cold weather is unlikely in the next 3 weeks and this is one such occasion 

[Nick F]

3 hours ago, Snowmut said:

Not pretending to know what i'm talking about, but is that a PV split I see,

 

 Ithink thats good news!!

It's not a polar vortex split, just a lobe of cold uppers spreading down from the Arctic. Think we'll have to wait until the New Year for a split or displacement (see the discussion in the strat thread).

I can't see any big changes to the current pattern of mean trough to the west and NW for much of this month with the strongly +AO/NAO and the trop vortex dominating Greenland. The strong El Niño climo for December and westerly QBO doesn't encourage change, nor does the forecast more amplified MJO through phases 4 and 5 help us ou of this rut either, below are Dec MJO plots with 4 and 5 with ENSO 3.4 greater than 0.5

There are, however further wave-1 and 2 fluxes forecast, which will help disturb the PV over time, but don't expect to see the effects of this until Jan or Feb. Any trop pattern change can still occur before this though but not looking likely for a few weeks IMO.

i suppose one positive that the models are hinting at is the trend for N Atlantic/NW Europe trough img to dig deeper with time with the jet dropping further south to allow bouts of cold PM incursions.

Edited December 12, 2015 by Nick F

[Airedalejoe]

42 minutes ago, BLAST FROM THE PAST said:

For me the contrast across the country is the talking point, overnight we could see up to 20c difference between parts of Scotland and Cornwall.  Even by day we'll see 10c+ difference.  So charts being posted targeting super mild aren't telling the current story for all UK, lots more going on; yep I'm stuck in the grip mild mush but I'm really fascinated by the contrasts . 

This is feature worth keeping an eye on, look at that little bump near Wales....more heavy rain heading to the wrong place?

 

 

BFTP  

Spot on there. Yes temps have been above average most of the time so far this winter up here but nothing exceptional, seen many many spells of much milder weather over the years! I love the cold and snow but on the other side of the coin I wouldn't mind the higher temps those further south experience, would make my cycling less of a chore! 

Car needed a good ice scraping yesterday and today is also cold, hopefully not long before we see some of the white stuff! As others have said, GFS hinting at a colder set up for Christmas.

Following screenshot from the weather app on my phone tells the story of most of this whole years temps. Huge difference north to south in England alone.

[knocker]

Looking closely at this morning's ops outputs and the anomalies one can arrive at but one conclusion. The next 14 days portend to be very wet and windy interspersed with some respite. Temps generally above, or around,  average but will dip in the incursions of the Pm wintry stuff but frankly that's academic. The two main concerns as far as i can see are how much rainfall will be dumped, and where, as obviously some areas of Britain have had quite enough already and whether we cop a major wind storm which is a distinct possibility.

I see you have been following Sam Lillo IDO

Edited December 12, 2015 by knocker

[Nouska]

With all the discussion about mid-range mean charts, as an experiment in verification, I'm following the ECM means for Christmas day - still maintaining a signal for 'cold zonality'  (hate the expression but everyone knows what it means).

Charts for mid-day on the 25th.

850 temp     Z500 

I would argue, that at this early stage, quite good agreement from the two main models.

GFS showed the stormy Christmas/Boxing day of 2013 way out at far reaches and consistently brought to time.

[gottolovethisweather]

50 minutes ago, IDO said:

All well and good saying weather can change! but it won't change just because it can, there has to be a reason. Maybe some meat on the bone as to why you think there will be a sudden change in the NH synoptics? We have one of the coldest strat PV for a while and it is still cooling. This will promote a positive AO and that means no sustained cold likely in our region. 

  GFS Mean verification: 

Not discounting a bit of a PM flow in the mobile zonal setup but I am sure the majority are looking for a sustained blocked pattern that will provide a longer lasting cold spell? At the moment none of the drivers of the weather have any lead to a colder setup.

As for D6 being FI, that is clearly wrong, yes for surface conditions, but not for long wave patterns. The GFS Mean is performing very well at D10, much better than it usually does, currently 0.638 (last week over 0.7 on average), and that suggests that FI is probably nearer D15 than D6. 

No need for meat on the bones from me, I'd stated my beliefs in several posts previously. No issues with your posts either of course, as I believe in, the more information/forecasts posted up in here the better. Its just a "come in January" type comment hardly sums up the overall NH/global picture and it was mainly taht which I and several others took exception to. Keep up with your analysis and yes, providing charts against your posts is definitely the way forward for one and all where at all possible. This post from me yesterday might interest you IDO, more especially the first paragraph is precisely how I currently things out into the far reaches of FI.

 

 

As for noting where FI might begin, I always use the ensembles as a guide to this and from memory, the divergence in individual member runs increases greatly from around the 17th/18th December as things currently stand. The bigger  H500/troposphere/stratosphere picture is of course the key driver as to what we might get down the line, I agree.

Edited December 12, 2015 by gottolovethisweather

[IDO]

5 minutes ago, knocker said:

Looking closely at this morning's ops outputs and the anomalies one can arrive at but one conclusion. The next 14 days portend to be very wet and windy interspersed with some respite. Temps generally above, or around,  average but will dip in the incursions of the Pm wintry stuff but frankly that's academic. The two main concerns as far as i can see are how much rainfall will be dumped, and where, as obviously some areas of Britain have had quite enough already and whether we cop a major wind storm which is a distinct possibility.

I see you have been following Sam Lillo IDO

Yes I do, he is a PhD student but a rising star in the "weather" field I suspect. Amazing what these experts know and no end to the learning curve for weather! 

GFS 06z follows the 0z to D9 in overall pattern.

[knocker]

2 minutes ago, IDO said:

Yes I do, he is a PhD student but a rising star in the "weather" field I suspect. Amazing what these experts know and no end to the learning curve for weather! 

GFS 06z follows the 0z to D9 in overall pattern.

All right for you but I struggle to make sense of some of his graphics.

[Summer Sun]

Thursday is still looking like a very mild day for most parts of the UK

At 3am temps are widely in double figures with the exception of northern Scotland

By 15:00 temps are widely in the mid teens for England and Wales some northern parts of Scotland hold onto single figure highs

Edited December 12, 2015 by Summer Sun

[johnholmes]

I wonder if anyone is interested in the here and now?

An interesting few hours as the low over Eire tracks towards the N Sea. Just what will be the exact track-where will get the worst of the rain-which high ground will get snow-will it lie? All these and folk seem obsessed with day x-y-z. Nothing wrong with that but some lucky ones will see snow today over northern England. I think the track of the low, judging from the latest data I can get hold of, suggests it wil exit somewhere between Bridlington and Newcastle into the N Sea. Another 2-3 hours and that widish idea should be able to refine somewhat.

As to the longer term, no matter which model you use, the end result will be the same, no major upper air pattern change for at least two weeks. So much of the same with perhaps a tendency to edge the overall temperature down a bit. As to a white Xmas well timing will be crucial for any short burst of Pm air to that. Not impossible for some, but, on current evidence, more likely the further north one lives and the higher up as well.

anomaly charts below

httphttp://www.cpc.noaa.gov/products/predictions/610day/500mb.php://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

for immediate watching a link to the weather chart for today

http://meteocentre.com/analyse/map.php?hour=0&lang=en&map=UK

on my pc this morning it is a bit slow to load.

 

[Frosty.]

The Gfs 6z op run shows more interest for those of us who prefer seasonal weather in winter rather than constant mild mush, the jetstream digs further south and yes, there is some wintry weather across the uk during the christmas period...hope it's right!!

[ForeverPomeroysnow]

28 minutes ago, johnholmes said:

I wonder if anyone is interested in the here and now?

An interesting few hours as the low over Eire tracks towards the N Sea. Just what will be the exact track-where will get the worst of the rain-which high ground will get snow-will it lie? All these and folk seem obsessed with day x-y-z. Nothing wrong with that but some lucky ones will see snow today over northern England. I think the track of the low, judging from the latest data I can get hold of, suggests it wil exit somewhere between Bridlington and Newcastle into the N Sea. Another 2-3 hours and that widish idea should be able to refine somewhat.

As to the longer term, no matter which model you use, the end result will be the same, no major upper air pattern change for at least two weeks. So much of the same with perhaps a tendency to edge the overall temperature down a bit. As to a white Xmas well timing will be crucial for any short burst of Pm air to that. Not impossible for some, but, on current evidence, more likely the further north one lives and the higher up as well.

anomaly charts below

httphttp://www.cpc.noaa.gov/products/predictions/610day/500mb.php://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

for immediate watching a link to the weather chart for today

http://meteocentre.com/analyse/map.php?hour=0&lang=en&map=UK

on my pc this morning it is a bit slow to load.

 

Indeed John some interesting weather about today and some very snowy scenes in a lot of areas over in Ireland, pictures have been posted in the regional thread for those interested 

[johnholmes]

some nice shots of the white stuff thanks for the link.

[Airedalejoe]

59 minutes ago, johnholmes said:

I wonder if anyone is interested in the here and now?

An interesting few hours as the low over Eire tracks towards the N Sea. Just what will be the exact track-where will get the worst of the rain-which high ground will get snow-will it lie? All these and folk seem obsessed with day x-y-z. Nothing wrong with that but some lucky ones will see snow today over northern England. I think the track of the low, judging from the latest data I can get hold of, suggests it wil exit somewhere between Bridlington and Newcastle into the N Sea. Another 2-3 hours and that widish idea should be able to refine somewhat.

As to the longer term, no matter which model you use, the end result will be the same, no major upper air pattern change for at least two weeks. So much of the same with perhaps a tendency to edge the overall temperature down a bit. As to a white Xmas well timing will be crucial for any short burst of Pm air to that. Not impossible for some, but, on current evidence, more likely the further north one lives and the higher up as well.

anomaly charts below

httphttp://www.cpc.noaa.gov/products/predictions/610day/500mb.php://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

for immediate watching a link to the weather chart for today

http://meteocentre.com/analyse/map.php?hour=0&lang=en&map=UK

on my pc this morning it is a bit slow to load.

 

Haha, just what I was thinking. Rain is changing over to snow here at 60m asl, must be turning white on the hills by now. 

[johnholmes]

On 3 December 2015 at 9:48 AM, BLAST FROM THE PAST said:

Hi John,  The theme is Ridge to W ridging north, trough to E/SE bringing northerly quadrant flow veering to NE to E at times with set up 'developing' around 10-14 which I suggested will take us up to Xmas as a general theme .  No individual run is right/wrong it's all about the overall theme.  I must be looking at different GFS because it has been suggesting such a development for a week now in FI?  Anyway I still am optimistic for such a development, I wouldn't have forecast it if I wasn't optimistic.  But let's be clear its not a 2010 scenario I am optimistic for.  A colder theme with chances of quite wintry conditions at times. 

Of course I would like to see your method bring a supporting quote from you....I await with  huge optimism and if not.....then back to the drawing board 

 

BFTP

Just wondering Fred where your cold spell for the South has got to. Even the North has so far had just shortish cold spells?

As you can see fro a post a little before this I still see no more than short bursts of Pm air?

your thoughts?

[phil nw.]

One thing that's interesting about this zonal pattern is the jet wavering across the UK.Not good of course from the problem of too much rain as we have seen, but the proximity of the colder air sees the situation we have currently with this north-south split.

I think we are all aware now that although there's no indication of any cold blocking in the next couple of weeks it still leaves the chances of polar maritime incursions from the north west.This would be possible following  even modest amplification upstream  of the flow as this will help return the jet south at intervals.

With this in mind let's keep an eye of Christmas week.A look at the gefs spreads indicate the greatest area of uncertainty is the track of the Atlantic lows-see Christmas day, just for fun at this stage.

if the jet just moves a little further south then more of the UK will see that Polar air.

A look at the latest 2m temp graph

continue to see temperatures dropping back for the Christmas period,further north of course could well be colder.

Certainly expecting mild all the way to Christmas and beyond is not a done deal yet as even in this westerly pattern a little realignment of the jet can make a difference as we have seen up north today.

I think there is enough uncertainty on detail in week 2 of the model runs to at least keep an open mind on the Christmas weather.

 

Edited December 12, 2015 by phil nw.

[Frosty.]

Agreed Phil, i'm thinking the jet will be dropping further south just in time for the christmas period with a Pm airmass dominating for a change!! 

[phil nw.]

1 minute ago, Frosty. said:

Agreed Phil, i'm thinking the jet will be dropping further south just in time for the christmas period with a Pm airmass dominating for a change!! 

Yes Frosty i think so far this season the mean jet track is further south than in many of the mild Winter periods and it does seem prone to some meandering.

Of course next week we see the milder ridging but as that passes before Christmas it does leave enough wriggle room for something colder as those ens are indicating.