Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[IDO]

The GFS op was a whopper of an outlier, following on from the outlier on the 06z. You can see from the Dutch temp ensemble's graph this highlighted even more significantly:

 

 

The control though not as pronounced is also likely an outlier. With the hi-res runs so far from the members it remains the case that synoptics after around T120 should be treated with caution.

 

ECM at T72 still picking up that satellite low, this time further north compared to the 0z at the same time:

 

 

[shaky]

Cant post charts for some reason but i gota say the ecm 96 hour is the chart of the day if it's all snowfall your after!! Elongated low and much slacker!!

[I remember Atlantic 252]

Cant post charts for some reason but i gota say the ecm 96 hour is the chart of the day if it's all snowfall your after!! Elongated low and much slacker!!

 

It seems to track too far east, need to be on the eastern side of the low, surely cannot be all snow, just a wintry mix at low levels in the W and N/NW Midlands, most the snow seems to be in the north sea, need the low to track much further west, to keep the mild sector away

[snowking]

Fairly big correction SW by the ECMWF vs 24 hours ago:

 

[BlueHedgehog074]

Interestingly, this was what the 12Z GFS was modelling for Thursday 22nd January last Wednesday. When comparing that chart to tonight's 12Z GFS chart for the 22nd and you'll notice how similar both are:

(12 GFS for Thursday 22nd from Wednesday 14th January)

(Tonight's 12Z GFS for Thursday 22nd)

While models do vary from run to run, and while Thursday is still a number of days away, it's quite nice to see the consistency the GFS has shown for that day. Admittedly not looked at every GFS run in the last few days, so possible that it's chopped and changed the outlook for Thursday a few times (although I suppose the idea of Low Pressure dropping to our South or South-East next week with possible snow still seems to be the case). There are also some little differences between both the charts above - for example; the 2nd chart shows lower 500mb heights over Greenland. Plus, the High-Pressure system over Scandinavia looks slightly bigger and a bit more organised. The general pattern, though, appears to be the same with both showing a little Low over Southern/South-Eastern UK, a blocking High to our North and a slightly amplified Azores High to our West.

It's clear that all models should be considered (as well as the ensembles/anomaly charts) to see how next week continue's to shape up, but this example could perhaps add an extra layer of confidence regarding the outlook for the middle of next week.

Edited January 17, 2015 by DiagonalRedLine

[Snowy L]

http://www.wetterzentrale.de/pics/Recm1201.gif

 

That is so close to an undercut, still think the Azores will ruin any potential undercut though, it's just too eager to push towards the UK on every model.

[nick sussex]

An interesting ECM T96hrs with that shallow elongated low but still too early to call this in terms of the snow/rain boundary.

 

At T120hrs really very interesting now, the Azores high unable to ridge ne, surely the energy must head se from that low to the west after this.

 

PS A big thank you to Sylvain from Meteociel for those new GEFS tables, a really great new addition.

[BurwellWeatherWatch]

 

Back to models though - and I think UKMO is too quick to dispense the cold air which can be notoriously hard to displace. Ensembles seem to be coming round to the idea of an extension of the cold, so writing things off from Thurs/Fri is premature. Perhaps 30-40% chance of an E'ly by next weekend.

 

That said some marginality which was what we have midweek is probably more exciting than a 'straightforward' bone chilling E'ly which could turn rather dry. Marginality by its very nature has the potential to go 'wrong' but also the potential to deliver in a much more stunning way - e.g. for a small swathe of the country on Boxing Day.

 

Weds looks good for somewhere but impossible to know where until nearer the time!

 

Good luck to everyone this week.

Edited January 17, 2015 by Paul

[Dan the Man]

If only this would come to pass, can you imagine...the entire country enjoying snow

 

This place would be either bedlam, or quiet as we'd all be out dancing around like crazed kids waving hands in the air and zig zagging down the roads yelling and laughing. 

 

knowing my luck that would be the exact moment the local mental assylum van drove past and I'd be picked up and carted off to a crazy home before I'd even made my first snow woman :-)

 

 

A bit pointless posting this isn't it? Showing heavy snow all the way down to Gibraltar, Costa del Sol, Northern Morocco and Algeria.

Pigs will fly first.

[Man With Beard]

My reading of the ECM so far is:

Tuesday: Snow north of a line from N Wales to somewhere in E Anglia

Wednesday: Precipitation (where there is any) falling as snow everywhere except extreme SW.

Thursday: Possible snow in SE.

Hold on, that sounds a bit like the forecasts people were making a couple of days ago - have the models simply gone full circle?!?

[shaky]

My snow line for Tuesday is anywhere from east wales east and northwards!! Southern extent the m4!!! South wales and southwest england miss out!! Remember its a slack flow with uppers of -4 or lower and surface cold in place!!

[Long haul to mild]

The ECM is with the UKMO in elongating the trough from the North West, whereas the GFS still splits the low off and drops it as a single entity through the UK, bringing in the Easterly flow afterwards.

 

I wonder which one is right? Personally, I'd expect the UKMO/ECM to be correct here as the timeframes seem too short for them both to be wrong. We shall see though!

[IDO]

At D7 the three main ops:  

 

So if the ops are a guide we will be out of the flow of the trough by D7.

Edited January 17, 2015 by i'm dreaming of...

[nick sussex]

If the low to the west could be a bit more negatively tilted at T120hrs we might see better trough disruption, I expected the T144hrs to look better especially with the Italian low in a good position and the Azores high not ridging into the gap.

[Mucka]

My reading of the ECM so far is:

Tuesday: Snow north of a line from N Wales to somewhere in E Anglia

Wednesday: Precipitation (where there is any) falling as snow everywhere except extreme SW.

Thursday: Possible snow in SE.

Hold on, that sounds a bit like the forecasts people were making a couple of days ago - have the models simply gone full circle?!?

 

I think people are oversimplifying things with a North/South split TBH. It will also be West/East and diagonal lines won't cut it. Much more nuanced and localised than that by the look of things. 

[snowray]

ECM T96 looks very snowy, I would think in terms of a wide band of heavy snow down the center of the Uk moving South. By T120 still some snow in the extreme SE, very cold at the surface with freezing rain on the Western boundary. 

Chart of the day and within 5 days...for snow lovers.

[gottolovethisweather]

Forget far reaches of FI, these are two charts I personally saviour for parts of the UK waiting for a long overdue snowfall and these both fall within the reliable on the 20th and 21st January respectively.

 

I know, judging one operational run is isolation is fraught with danger and that there are many parameters to consider when looking for those magic white crystals, however, these two charts look tasty to say the least. I ain't looking for a breakdown or considering deep FI when we have this showing up on our doorsteps in the meanwhile. Good luck for the longer-range weather hunt in the meanwhile.

 

t+72hrs

 

 

t+96hrs

 

Edited January 17, 2015 by gottolovethisweather

[TSNWK]

At D7 the three main ops:  gfs-0-168 (10).pnggem-0-168 (1).pngECM1-168 (5).gif

 

So if the ops are a guide we will be out of the flow of the trough by D7.

Not much difference between any of those and I'm sure UKMO would be similar if the 144 was anything to go by. So let's enjoy this week folks, with some luck the milder weather from D7 will short lived and we could be looking at round two on the models.

[Summer Sun]

At D7 the three main ops:  gfs-0-168 (10).pnggem-0-168 (1).pngECM1-168 (5).gif

 

So if the ops are a guide we will be out of the flow of the trough by D7.

 

If the Atlantic does manage to break through during next weekend we could have a snowy breakdown proceeding any less cold temperatures something to bear in mind for next weekend

Edited January 17, 2015 by Summer Sun

[snowray]

My snow line for Tuesday is anywhere from east wales east and northwards!! Southern extent the m4!!! South wales and southwest england miss out!! Remember its a slack flow with uppers of -4 or lower and surface cold in place!!

Uppers of -7, -8, -9c around, low dew points and the stagnant air within the low make me think snow right down South of London, particularly Weds night. Maybe not on the coast but looking pretty damn cold.

[Captain Shortwave]

At day 4, the ECM pretty much sits between the GFS and UKMO, whilst the ECM has the elongated trough, you can see the low is further south and already see the pinch point developing where the low will cut off. Any precipitation looks like being a wintry mix for south western areas, eastern areas look good for snow if the precipitation holds. A lot of uncertainty and still the chance of an easterly to end the week.

Edited January 17, 2015 by Captain shortwave

[MR EXTREMES]

Forget far reaches of FI, these are two charts I personally saviour for parts of the UK waiting for a long overdue snowfall and these both fall within the reliable on the 20th and 21st January respectively.

I know, judging one operational run is isolation is fraught with danger and that there are many parameters to consider when looking for those magic white crystals, however, these two charts look tasty to say the least. I ain't looking for a breakdown or considering deep FI when we have this showing up on our doorsteps in the meanwhile. Good luck for the longer-range weather hunt in the meanwhile.

t+72hrs

ECM 12z 170115 H500 UK t+72 hours 1300CET 200115.GIF

t+96hrs

ECM 12z 170115 H500 UK t+96 hours 1300CET 210115.GIF

Yes please what a stunning chart even for the southern crew in fact any precipitation in most of the uk would be of snow.

And yes even on the south coast seen snow fall with uppers of -4

Edited January 17, 2015 by emotional rollercoaster

[gottolovethisweather]

My reading of the ECM so far is:

Tuesday: Snow north of a line from N Wales to somewhere in E Anglia

Wednesday: Precipitation (where there is any) falling as snow everywhere except extreme SW.

Thursday: Possible snow in SE.

Hold on, that sounds a bit like the forecasts people were making a couple of days ago - have the models simply gone full circle?!?

 

Yes it does and you'll also note that I tend to only follow the 12z outputs in an attempt to garner a clear trend as to where we might be heading out in la la land and to that end, the latest runs do not surprise me. Also, folk can choose to study runs consecutively should they wish and if that is their prerogative, fine, just don't expect consistency between runs. It is often best to do as JH and a certain few others have suggested in the past, compare 12zs with 12zs or 0zs against 0zs etc. Above all else have fun and smile while you post. 

Edited January 17, 2015 by gottolovethisweather

[I remember Atlantic 252]

FAX chart has Tuesdays front over Wales midday, so not sure on that chart if ppn will reach as far East as the midlands, but it would be cold, and no danger of rain/sleet, east wales eastwards

Edited January 17, 2015 by Ilovethesnow

[Ali1977]

Some tweets from Matt Hugo ref major warming signs from the GFS, and having just looked at FI on the GEFS you can see the PV is all over the place.....has Feb got something interesting to give us I wonder....

This week still looking good for snow for some, especially those on higher ground but potential just about anywhere!!!