Model output discussion pm 13/01/2016

[karlos1983]

21 minutes ago, nick sussex said:

Good grief whats going on!

Theres a marked difference between the GEFS 00hrs at T114hrs and the new GEFS 06hrs at T108hrs. A lot more keep high pressure to the north.

This is the GEFS 00hrs ensemble mean at T114hrs on the left and the GEFS 06hrs to T108hrs on the right:

If you look at each ensemble member then the difference is more marked in terms of the big jump in members keeping the high to the north.

The models seem to be making a lot of drama over the early timeframe, we should bear in mind this volatility could still go the wrong way in terms of the outlook because it doesn't give you much confidence when theres these big switches in ensembles within the normally more reliable timeframe.

 

I count 7 that give us some form of trough disruption and there are a couple that give a Scandi high, albeit that it doesn't hang around long. lots to play for still, finely balanced.

[nick sussex]

4 minutes ago, karlos1983 said:

I count 7 that give us some form of trough disruption and there are a couple that give a Scandi high, albeit that it doesn't hang around long. lots to play for still, finely balanced.

Our favourite go to model the NAVGEM! has also corrected the pattern further west with better heights to the north at T96hrs compared to its 00hrs to T102hrs.

[weather eater]

1 hour ago, Bristle boy said:

Mixed signals and considerable 'scatter' from midweek next week, according to Ian F latest.

I wouldnt get too hung up on period post next Monday. Models in state of confusion it seems.

A welcome piece of news though I'm not sure we need Ian to tell us that, as it seems apparent in the models. Not to mention we should all be doing that anyway.

[Pennine Ten Foot Drifts]

I've got to admit I'm struggling to understand where people are seeing positives at the moment ? I know there's a lot of 'uncertainty', but twas ever thus in mid to FI model range, and all I'm seeing in any of the models beyond T144 is a generally consistent agreement, and a firming up of a trend which started some days ago i.e. increasingly higher pressure to our south and east, lower pressure across the whole GIN corridor, meaning air sourced predominantly from our west/south west, and an increasingly organised PV over N. Canada - none of which adds up to any real cold for the UK. For example, GFS and ECM at T144:

Then further out:

If anything the ECM is nearer a Bartlett than anything else in FI !!!:

Now I know these are charts from one run, but they pretty much encapsulate the way the models have been developing for a number of days now i.e. a steady backing away from any real pressure rises to our north or east, which is generally speaking a pre-requisite for proper UK cold. Of course the UKMO has been a little different to GFS and ECM recently, but it just seems to be playing catch-up for some reason at the moment, in that it's been following the other two more or less, but always a few days later.

So all in all, I must say I really don't see much hope of any cold deep enough to lead to widespread UK snowfall this side of February at the earliest, unfortunately.

Edited January 14, 2016 by Pennine Ten Foot Drifts
Spelling !!!

[Man With Beard]

ECM ens London latest - main cluster cold until 20th/21st (as has been consistently shown for days), but in general, a warm-up of sorts from 21st/22nd/23rd onwards. I can't really see how anyone can forecast the cold continuing into next weekend based on this (though that's not to say it won't happen!)

[chrisbell-nottheweatherman]

4 minutes ago, Man With Beard said:

ECM ens London latest - main cluster cold until 20th/21st (as has been consistently shown for days), but in general, a warm-up of sorts from 21st/22nd/23rd onwards. I can't really see how anyone can forecast the cold continuing into next weekend based on this (though that's not to say it won't happen!)

Note, though, that, not only does the operational run go colder again late in the month, but so does the main ensemble cluster.  By the end of the run, there aren't that many members anywhere near 10C, and quite a few heading back down to nearer 0C.

Edited January 14, 2016 by chrisbell-nottheweatherman
Correcting typo.

[nick sussex]

Pennine the issue isn't so much perhaps the medium term, so yes theres a stronger signal to push lower heights east and reform the PV to the north.

Its what happens before that's more difficult to forecast. And of course for the UK you often find it at the boundary between cold and milder.

So detail wise its the issue of trough disruption/ shortwave energy and where that goes regarding snow prospects for the UK.

You can see why its turning into a forecasting problem for the UKMO because the models simply don't give any confidence.

And of course with these set ups early changes start to manifest in bigger ways as you go forward, so to be honest I'm not sure we've seen the last of the changes.

I think currently the big forecasting headache is whether its a snow to rain outcome or shortwave running more se so for some areas snow then the cold hanging on a bit longer.

Theres of course the possibility that the first shortwave might be edged further south missing most of the UK.

Very hard to say at this point what will happen.

 

Edited January 14, 2016 by nick sussex

[weather eater]

UKMO output this morning should come as no surprise. As over proggessive re the Atlantic the GFS is, the UKMO is with HLB. I have no idea how good its verification stats are but I have never trusted it 120hr plus  output. Overall my opinion on the models is still, that we will see the UKMO backtrack further. The ECM seem utterly unsure and the GFS still looks to me like it has been nearer the mark all along. Changes in its output have for me just been standard inter run variation and evolution not small steps to the solution the UKMO has been showing over the last couple of days. I hate to bang on with this word but evolution is constant with modelling synoptic patterns and even tiny changes have big impacts for the UK. Consequently It is perfectly possible that we may get a little bit more mileage out of this spell yet. currently sleeting in my little corner of the fens and getting rather windy.

[Pennine Ten Foot Drifts]

13 minutes ago, nick sussex said:

Pennine the issue isn't so much perhaps the medium term, so yes theres a stronger signal to push lower heights east and reform the PV to the north.

Its what happens before that's more difficult to forecast. And of course for the UK you often find it at the boundary between cold and milder.

So detail wise its the issue of trough disruption/ shortwave energy and where that goes regarding snow prospects for the UK.

You can see why its turning into a forecasting problem for the UKMO because the models simply don't give any confidence.

And of course with these set ups early changes start to manifest in bigger ways as you go forward, so to be honest I'm not sure we've seen the last of the changes.

 

Yes I understand that Nick, and there is slight potential for some front edge snow Sunday night into Monday morning:

but beyond that the overall pattern has been fairly consistent over the past few days. Now of course that whole pattern might be based on incorrect modelling in the shorter term, but right now as it stands the possibility of developments from where we are now leading to anything significantly cold in the next few weeks seems to be the outside bet.

[jvenge]

2 minutes ago, weather eater said:

UKMO output this morning should come as no surprise. As over proggessive re the Atlantic the GFS is, the UKMO is with HLB. I have no idea how good its verification stats are but I have never trusted it 120hr plus  output. Overall my opinion on the models is still, that we will see the UKMO backtrack further. The ECM seem utterly unsure and the GFS still looks to me like it has been nearer the mark all along. Changes in its output have for me just been standard inter run variation and evolution not small steps to the solution the UKMO has been showing over the last couple of days. I hate to bang on with this word but evolution is constant with modelling synoptic patterns and even tiny changes have big impacts for the UK. Consequently It is perfectly possible that we may get a little bit more mileage out of this spell yet. currently sleeting in my little corner of the fens and getting rather windy.

Some chap here posts verification starts fairly often and it is usually ranked ECM, UKMO and GFS if memory serves.

[Gibby]

4 minutes ago, jvenge said:

Some chap here posts verification starts fairly often and it is usually ranked ECM, UKMO and GFS if memory serves.

Yes it's me. Here's todays story.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO  and GFS at 99.4 pts respectively.  At 3 days ECM is leading with 97.6 pts to UKMO's 96.8 pts while GFS lags behind at 96.4 pts. At 5 days ECM leads with 90.1 pts to UKMO at 88.2 pts then GFS at 87.1 pts. Then at 8 Days ECM still leads at 66.2 pts over GFS's 63.2 pts. Finally at Day 10 ECM is ahead of GFS at 49.0 pts to 45.9 pts respectively. 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

[weather eater]

1 minute ago, jvenge said:

Some chap here posts verification starts fairly often and it is usually ranked ECM, UKMO and GFS if memory serves.

Problem is verification stats tend to iron out the creases and that may mean that particular models may have particular issues in some regards. 2 its ranking also does not mean it is always better than the next on the list, just usually. Why it comes to HL blocking patterns that are directly influencing our weather, I tend to work to the theory that if the GFS is not buying into it, then it will not happen. I cannot recall when this was not sound advice.

[nick sussex]

26 minutes ago, weather eater said:

Problem is verification stats tend to iron out the creases and that may mean that particular models may have particular issues in some regards. 2 its ranking also does not mean it is always better than the next on the list, just usually. Why it comes to HL blocking patterns that are directly influencing our weather, I tend to work to the theory that if the GFS is not buying into it, then it will not happen. I cannot recall when this was not sound advice.

I think someone linked to verification stats for regions of the NH a while back and that might be a better guide but unfortunately I can't remember now who it was! lol

If we could just get Europe then that would be a big help, I'll have a dig around, I might have saved that but not sure!

No luck so far but for all you model anoraks out there this is fun tool, which gives you a quick way to compare the 850's, pressure, precip forecasts from either the 00hrs or 12hrs outputs of the main models.

You can also just look at each model separately:

http://meteocentre.com/models/get_mgram.php?stn=London&mod=compar&run=00&var=std&lang=en&map=UK

Unfortunately the UKMO only shows 850's upto T72hrs, its a shame that the info past that point is held back.

I'd keep an eye on what the models do with pressure in Iceland, they have Reykjavik in that list and the higher the pressure stays there the better the outlooks likely to be in terms of cold for the UK.

 

Edited January 14, 2016 by nick sussex

[PolarWarsaw]

Looking at the charts this morning. 

I'm happy to take the GFS. It gives most people a good couple of hours of snow before the milder air wins out. Most people want snow not just cold weather, so I'm fairly sure that would go down well for most people. 

The UKMO/ECM look like a slow painful strangling of the cold and no snowy breakdown. No thanks for me. 

It now looks virtually nailed on that we see cold and frost until Monday or so, perhaps midweek if the UKMO/ECM are correct. Then it's a breakdown of sorts, a 'reset' and we aim for GP's torpedo for the months end. Plenty to be happy about IMO. 

[Yarmy]

11 minutes ago, nick sussex said:

I think someone linked to verification stats for regions of the NH a while back and that might be a better guide but unfortunately I can't remember now who it was! lol

If we could just get Europe then that would be a big help, I'll have a dig around, I might have saved that but not sure!

Nick, this is the link that IDO provided to me a little while back:

http://www.wpc.ncep.noaa.gov/mdlbias/

 

[nick sussex]

3 minutes ago, Yarmy said:

Nick, this is the link that IDO provided to me a little while back:

http://www.wpc.ncep.noaa.gov/mdlbias/

 

Thanks for that Yarmy. I'm still thinking that theres another one that popped up in here. If only I could remember the member who posted it!

[Geordiesnow]

I think people would accept a breakdown more if the current set up delivers more in the way of snow than it actually will but to be honest, the cold snap kind of went wrong from the moment the trough we had earlier in the week just would not move eastwards quick enough. 

I do hope we can get some severe frosts though before things do break down which I think will now, there is too much agreement in this now and I expect the PV to strengthen and the possibility of the bartlett high is increasing. I think the question will be, just how quick will the cold break down. 

[bryan629]

A lot of knee jerking going on this morning... so i thought i would paste 2 top posts in  what GP and Tamara said in their excellent posts yesterday in the old thread >>>>>>>>

 

CPC analogues rolled forward days 10-12 confirm the idea that we are heading towards an Atlantic ridge / Scandinavian trough solution in the last week Jan into early part of Feb... which might be useful as the models seem to be losing all coherence as we approach the business end of the winter.

 

Then followed by Tamaras post.... >>>>

We arrive today where the process is *almost* complete in the operational modelling of that trust in the trend being the friend being rewarded.  That said, people will understandably focus on snow potential, or lack of, until a breakdown (whenever that comes), but it can't be emphasised enough that based on troposphere>stratosphere destabilisation action on the vortex, the flip from record breaking anomalous warmth in December to what we now see today of undercutting lows slicing under embedded cold, is no mean feat under very strong w/QBO vortex conditions. It emphasises how even a turbo charged Nino regime under these conditions can demonstrate two very different patterns across the Atlantic. We saw the first pattern far too graphically over the last six weeks.

 

So with these in mind, and the huge amount of uncertainties the models have delivered this morning.. wouldn`t it be bettet just to call it intra run wobbling for now and keep the faith 

Edited January 14, 2016 by bryan629

[Nouska]

3 hours ago, Iceberg said:

The tropical storm is still a factor, not least because they expect the tropical charecteristics to remain for longer i.e more and longer embedded TM air. Also due to the energy (this is certain to become a sub-tropical hurricane imho and probably is already as NHC are kind of saying).

But for me the most important fact is the 70% chance of a further systems behind it (maybe 24 hrs behind). this prolongs the moisture, heat and waa, currently no models are forcasting a secondary follow on sub tropical storm, but NHC have just updated to give one a 70% chance.

Its all more uncertains into the mix. I am saying they increase or decrease the chances of cold weather, but they will certainly effect model progression.

Yes, this is important as whatever the NHC track shows, it is a blend of the models based on their expert opinion. Little differences in individual models have a big impact when such a surge of warm tropical air is introduced into the winter atmosphere.

Just like the difficulties last summer, when the reverse was true - models introducing large shots of Greenland cold into the warm summer atmosphere.

Will take a few runs yet to settle down.

Alex becomes the first hurricane of 2016.

AL, 01, 2016011412, , BEST, 0, 308N, 287W, 75, 981, HU, 34, NEQ, 120, 130, 100, 30, 1012, 300, 15, 0, 0, L, 0, , 0, 0, ALEX, D,

Last time a January hurricane was seen was 1938.

Such a rare sight - pic for posterity.

Edited January 14, 2016 by Nouska
wrong year

[Mucka]

Most interesting chart of the morning for me actually comes from the GFS 06z

This is the first time any  model has shown reamplification after an initial breakdown though it should be noted the UKMO only goes out 144 and has been far less inclined to breakdown the Atlantic ridge - perhaps a hint this morning it is slowly moving away from Atlantic blocking persisting but it just one run and this evenings output will tell us more. 

Looking to see if any of this evenings output repeats GFS 06z want to rebuild heights further East and if UKMO is getting on board with a quicker breakdown will be of most interest to me this evening but also looking at potential for a decent snow event as a prelude to any breakdown - my diary is still marked from a couple of days ago, "18th potential widespread snow England"

I think it is clear though that no model has fully resolved the energy distribution as the Azores low phases with the Atlantic trough and comes up against the Atlantic ridge - something I stated would likely have an impact upon this cold spell a few days ago and so it is proving.

I am going to stick my neck out a bit here and paint a different picture of what may actually occur and rather stupidly I am going to go into detail so feel free to dismiss this entirely as it is not modeled at all and so has to be considered low probability. (Some might call it hope-casting but I genuinely feel it is a possibility) 

Given that we can take nothing for granted my feeling is we will see a messy unconvincing attempt to breakdown the Atlantic ridge so quite possibly neither UKMO nor ECM nor GFS are right 120/144 and we may yet see something far more interesting or at l;east different.  Most of interest to those wanting snow and cold would be an elongated trough disrupting from the Atlantic into Northwest Europe around the 19th with potential for a cut off high appearing shortly thereafter somewhere perhaps just East of Iceland - don't take timing and locations too literally, I'm outlining a potential synoptic that could yet develop but it does require a leap of faith. Should that happen we would likely see low pressure further disrupting possibly across the South of the UK around the 21st with obvious potential for heavy snow (or rain depending on mixing and track). 

As I say that is likely an over detailed analysis of  charts that don't even exist so feel free to dismiss it as the machinations of an over imaginative weather geek.

[Kentish Snowman in Yorks]

3 minutes ago, Mucka said:

Most interesting chart of the morning for me actually comes from the GFS 06z

This is the first time any  model has shown reamplification after an initial breakdown though it should be noted the UKMO only goes out 144 and has been far less inclined to breakdown the Atlantic ridge - perhaps a hint this morning it is slowly moving away from Atlantic blocking persisting but it just one run and this evenings output will tell us more. 

Looking to see if any of this evenings output repeats GFS 06z want to rebuild heights further East and if UKMO is getting on board with a quicker breakdown will be of most interest to me this evening but also looking at potential for a decent snow event as a prelude to any breakdown - my diary is still marked from a couple of days ago, "18th potential widespread snow England"

I think it is clear though that no model has fully resolved the energy distribution as the Azores low phases with the Atlantic trough and comes up against the Atlantic ridge - something I stated would likely have an impact upon this cold spell a few days ago and so it is proving.

I am going to stick my neck out a bit here and paint a different picture of what may actually occur and rather stupidly I am going to go into detail so feel free to dismiss this entirely as it is not modeled at all and so has to be considered low probability. (Some might call it hope-casting but I genuinely feel it is a possibility) 

Given that we can take nothing for granted my feeling is we will see a messy unconvincing attempt to breakdown the Atlantic ridge so quite possibly neither UKMO nor ECM nor GFS are right 120/144 and we may yet see something far more interesting or at l;east different.  Most of interest to those wanting snow and cold would be an elongated trough disrupting from the Atlantic into Northwest Europe around the 19th with potential for a cut off high appearing shortly thereafter somewhere perhaps just East of Iceland - don't take timing and locations too literally, I'm outlining a potential synoptic that could yet develop but it does require a leap of faith. Should that happen we would likely see low pressure further disrupting possibly across the South of the UK around the 21st with obvious potential for heavy snow (or rain depending on mixing and track). 

As I say that is likely an over detailed analysis of  charts that don't even exist so feel free to dismiss it as the machinations of an over imaginative weather geek.

Sounds plausible to me Mucka.

All the while that cold pool is sitting just to the East of us, no solutions should be ruled in or out as anything looks possible next week given the model uncertainty.

[Frosty.]

Latest news from the woodshed is for the cold weather to persist for much if not all of next week with widespread frosts which could be severe, the east and southeast looks coldest throughout, even to the end of January. The west looks like becoming unsettled next week with a wintry mix of rain, sleet and snow and the highest risk of snow is when the Atlantic system edges further east into the deeper cold air...so, no return of mild mush next week, temps creeping back towards average by the end of next week across the northwest of the UK is the current thinking but overall it looks like staying wintry!

[TSNWK]

1 minute ago, Frosty. said:

Latest news from the woodshed is for the cold weather to persist for much if not all of next week with widespread frosts which could be severe, the east and southeast looks coldest throughout, even to the end of January. The west looks like becoming unsettled next week with a wintry mix of rain, sleet and snow and the highest risk of snow is when the Atlantic system edges further east into the deeper cold air...so, no return of mild mush next week, temps creeping back towards average by the end of next week across the northwest of the UK is the current thinking but overall it looks like staying wintry!

agreed! - I certainly felt that the hidden models are suggesting a continetal drift over the south-easten part of the uk for the foreseeable...

 

[TSNWK]

Just now, mickpips said:

That's basically just a rewording of the Met Office outlook 

exactly! me thinks the hidden models are suggesting no atlantic..

[Polar Maritime]

But what are the models showing.. Some charts to back up posts would be helpfull to members, Thanks.